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Sample records for experimental acrylic polymer

  1. Impact and fracture resistance of an experimental acrylic polymer with elastomer in different proportions

    Directory of Open Access Journals (Sweden)

    Fernanda de Carvalho Panzeri Pires-de-Souza

    2009-01-01

    Full Text Available The purpose of this study was to evaluate the impact and fracture resistance of acrylic resins: a heat-polymerized resin, a high-impact resin and an experimental polymethyl methacrylate with elastomer in different proportions (10, 20, 40 and 60%. 120 specimens were fabricated and submitted to conventional heat-polymerization. For impact test, a Charpy-type impact tester was used. Fracture resistance was assessed with a 3-point bending test by using a mechanical testing machine. Ten specimens were used for each test. Fracture (MPa and impact resistance values (J.m-1 were submitted to ANOVA - Bonferroni's test - 5% significance level. Materials with higher amount of elastomer had statistically significant differences regarding to impact resistance (p < 0.05. Fracture resistance was superior (p < 0.01 for high-resistance acrylic resin. The increase in elastomer concentration added to polymethyl methacrylate raised the impact resistance and decreased the fracture resistance. Processing the material by injection decreased its resistance to impact and fracture.

  2. Surface Structure of Acrylate Polymer Adhesives.

    Science.gov (United States)

    Roy, Sandra; Freiberg, Stephan; Leblanc, Claude; Hore, Dennis K

    2017-02-28

    Total internal reflection infrared (IR) absorption and visible-IR sum-frequency spectroscopies were used to study the role of acrylic acid in the evolution of surface structure in a poly(butyl acrylate)-based pressure-sensitive adhesive during the drying process. By monitoring these spectral responses and calculating the heterospectral correlation coefficients, we established that acrylic acid alters the nature of the molecular interactions at the surface. In the absence of acrylic acid, butyl acrylate orientation is driven by the packing of the polymer as the water evaporates. When acrylic acid is present, a rapid ordering of the copolymer takes place as a result of favorable hydrogen-bonding interactions with the surface.

  3. Electrochemical characterization of aminated acrylic conducting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Norma Mohammad [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Lestari Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor Darul Ehsan (Malaysia); Heng, Lee Yook [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Lestari Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor Darul Ehsan (Malaysia); Southeast Asia Disaster Prevention Research Initiative, Lestari Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor Darul Ehsan (Malaysia); Ling, Tan Ling [Southeast Asia Disaster Prevention Research Initiative, Lestari Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor Darul Ehsan (Malaysia)

    2015-09-25

    New attempt has been made to synthesize aminated acrylic conducting polymer (AACP) using precursor of phenylvinylsulfoxide (PVS). The process was conducted via the integration of microemulsion and photopolymerization techniques. It has been utilized for covalent immobilization of amino groups by the adding of N-achryiloxisuccinimide (NAS). Thermal eliminating of benzene sulfenic acids from PVS has been done at 250 °C to form electroactive polyacetylene (PA) segment. Characterization of AACP has been conducted using fourier transform infrared (FTIR), scanning electron microscopy (SEM) and linear sweep cyclic voltammetry (CV). A range of 0.3-1.25μm particle size obtained from SEM characterization. A quasi-reversible system performed as shown in electrochemical study.

  4. Use of Acrylic Acid Sodium Acrylate Polymer to Maintain Cocoa Seed Viability

    Directory of Open Access Journals (Sweden)

    Pudji Rahardjo

    2010-08-01

    Full Text Available The main problem of cocoa seed storage is moisture content of the seeds because cocoa seeds will germinate if cocoa seeds moisture content is high. The objective of this research is to maintain the cocoa seeds viability in storage using acrylic acid sodium acrylate polymer (AASAP. The function of AASAP is to absorb humidity in storage due to their ability to retain water and to prevent water loss. The experiment was conducted in a laboratory of Indonesian Coffee and Cocoa Research Institute and in Kaliwining Experimental Garden. This experiment was arranged by factorial randomized complete design, in wich AASAP dosages 0%; 0.1% (0.1 g/100 seeds; 0.2% (0.2 g/100 seeds, 0.3% (0.3 g/100 seeds, 0,4% (0,4g/100 seeds, combined with seeds storage period 1, 2, 3 and 4 weeks. The experiment used 3 replications and each repli cation used 100 seeds. Parameter of observation consisted of percentage of seeds germinated in storage, percentage of seeds infected by fungi in storage, seeds moisture content, percentage of seeds germination after storage, and early growth of cocoa seedlings. The results of the experiment showed that AASAP application with some dosages cocoa seeds storage cause to germinate in storage during 2 weeks. AASAP application with some dosages in cocoa seeds storage for 2 weeks would not result in infection by fungi and did not significantly affect seed germination after storage for 1, 2 and 4 weeks, and percentage of germination of cocoa seed after storage for 3 weeks decreased with increase dosage of AASAP. Higher dosage of AASAP would reduce early growth of cocoa seedling. Key words : Theobroma cacao, seed, acrylic acid sodium acrylate, seed storage, viabilty.

  5. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane...

  6. 76 FR 77709 - Butyl acrylate-methacrylic acid-styrene polymer; Tolerance Exemption

    Science.gov (United States)

    2011-12-14

    ... AGENCY 40 CFR Part 180 Butyl acrylate-methacrylic acid-styrene polymer; Tolerance Exemption AGENCY...-propenoate and ethenylbenzene (CAS Reg. No. 25036-16-2); also known as butyl acrylate-methacrylic acid...-risk polymers are described in 40 CFR 723.250(d). Butyl acrylate-methacrylic acid-styrene polymer...

  7. 40 CFR 180.1162 - Acrylate polymers and copolymers; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Acrylate polymers and copolymers... RESIDUES IN FOOD Exemptions From Tolerances § 180.1162 Acrylate polymers and copolymers; exemption from the requirement of a tolerance. (a) Acrylate polymers and copolymers are exempt from the requirement of a...

  8. 40 CFR 721.324 - Alkoxylated acrylate polymer (generic).

    Science.gov (United States)

    2010-07-01

    ...). 721.324 Section 721.324 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... subject to reporting. (1) The chemical substance identified generically as alkoxylated acrylate polymer... A of this part apply to this section except as modified by this paragraph. (1) Recordkeeping...

  9. N-Butyl acrylate polymer composition for solar cell encapsulation and method

    Science.gov (United States)

    Gupta, Amitava (Inventor); Ingham, John D. (Inventor); Yavrouian, Andre H. (Inventor)

    1983-01-01

    A polymer syrup for encapsulating solar cell assemblies. The syrup includes uncrosslinked poly(n-butyl)acrylate dissolved in n-butyl acrylate monomer. Preparation of the poly(n-butyl)acrylate and preparation of the polymer syrup is disclosed. Methods for applying the polymer syrup to solar cell assemblies as an encapsulating pottant are described. Also included is a method for solar cell construction utilizing the polymer syrup as a dual purpose adhesive and encapsulating material.

  10. Acoustic Performance of Resilient Materials Using Acrylic Polymer Emulsion Resin

    Directory of Open Access Journals (Sweden)

    Haseog Kim

    2016-07-01

    Full Text Available There have been frequent cases of civil complaints and disputes in relation to floor impact noises over the years. To solve these issues, a substantial amount of sound resilient material is installed between the concrete slab and the foamed concrete during construction. A new place-type resilient material is made from cement, silica powder, sodium sulfate, expanded-polystyrene, anhydrite, fly ash, and acrylic polymer emulsion resin. Its physical characteristics such as density, compressive strength, dynamic stiffness, and remanent strain are analyzed to assess the acoustic performance of the material. The experimental results showed the density and the dynamic stiffness of the proposed resilient material is increased with proportional to the use of cement and silica powder due to the high contents of the raw materials. The remanent strain, related to the serviceability of a structure, is found to be inversely proportional to the density and strength. The amount of reduction in the heavyweight impact noise is significant in a material with high density, high strength, and low remanent strain. Finally, specimen no. R4, having the reduction level of 3 dB for impact ball and 1 dB for bang machine in the single number quantity level, respectively, is the best product to obtain overall acoustic performance.

  11. Strategic design and fabrication of acrylic shape memory polymers

    Science.gov (United States)

    Park, Ju Hyuk; Kim, Hansu; Ryoun Youn, Jae; Song, Young Seok

    2017-08-01

    Modulation of thermomechanics nature is a critical issue for an optimized use of shape memory polymers (SMPs). In this study, a strategic approach was proposed to control the transition temperature of SMPs. Free radical vinyl polymerization was employed for tailoring and preparing acrylic SMPs. Transition temperatures of the shape memory tri-copolymers were tuned by changing the composition of monomers. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses were carried out to evaluate the chemical structures and compositions of the synthesized SMPs. The thermomechanical properties and shape memory performance of the SMPs were also examined by performing dynamic mechanical thermal analysis. Numerical simulation based on a finite element method provided consistent results with experimental cyclic shape memory tests of the specimens. Transient shape recovery tests were conducted and optical transparence of the samples was identified. We envision that the materials proposed in this study can help develop a new type of shape-memory devices in biomedical and aerospace engineering applications.

  12. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Science.gov (United States)

    2010-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl acrylate...

  13. Acrylic interpenetrating polymer network dielectric elastomers for energy harvesting

    Science.gov (United States)

    Brochu, Paul; Niu, Xiaofan; Pei, Qibing

    2011-04-01

    Dielectric elastomer energy harvesters are an emerging technology that promise high power density, low cost, scalability, and the capability of fitting niche markets that have yet to be exploited. To date, materials issues that limit their overall performance have hampered the full potential of these devices. In order to supplant existing technologies, even in niche markets, dielectric elastomer generators must increase their reliability and energy density. Previous work has indicated that stiffer elastomers should be capable of higher energy densities; the increased stiffness of the elastomer films should results in lower Maxwell pressure induced strains, and thus allow the elastomer to relax further, resulting in a larger swing in capacitance and larger energy gains. In this paper we examine the use of VHB-based acrylic interpenetrating polymer network dielectric elastomers with a trimethylolpropane trimethacrylate additive network for energy harvesting purposes. We test films with varying additive content and compare their performance with highly prestrained VHB acrylic elastomers. We show that by increasing additive content, Maxwell induced strains can be suppressed and larger energy gains can be achieved at higher bias fields. Moreover, the introduction of the additive network stabilizes the highly prestrained acrylic elastomers mechanically, thereby increasing their mechanical robustness. However, the interpenetrating polymer network films suffer from an increase in viscoelastic behavior that hinders their overall performance.

  14. Biodegradation and sorption properties of polydisperse acrylate polymers.

    Science.gov (United States)

    Rittmann, B E; Sutfin, J A; Henry, B

    Polyacrylate (PA), which is widely used in disposable diapers, is synthesized by polymerization and cross-linking of acrylate. During the synthesis, 3-6% of the polyacrylate polymers is not incorporated into the absorbent material, but remains soluble. If the soluble PA is mobilized from a landfill, it could enter the groundwater. Therefore, the biodegradation and adsorption properties of soluble polymers contained in PA are determined in this study. The soluble PA is highly polydisperse, and the fraction tested has a weight-average molecular-weight of 16,700 and a range extending from 10(3) to 10(5). Sand-column tracer tests show that about 1% of the polyacrylate is unadsorbed, but the remainder has a retardation factor that averages at least 58. Biodegradation kinetics are determined in completely mixed biofilm reactors having a methanogenic consortium grown on glucose. The polyacrylate fraction, as well as glucose and acrylate, are removed and mineralized to CO2. The Monod parameters for the polyacrylate are: maximum specific rate of substrate utilization = 0.0016 gC/g biomass-day, and half-maximum-rate concentration = 0.79 gC/m3. Although these kinetics are much slower than for glucose and acrylate, significant degradation and mineralization are observed.

  15. Plant oil-based shape memory polymer using acrylic monolith

    Directory of Open Access Journals (Sweden)

    T. Tsujimoto

    2015-09-01

    Full Text Available This article deals with the synthesis of a plant oil-based material using acrylic monolith. An acrylic monolith bearing oxirane groups was prepared via simple technique that involved the dissolution of poly(glycidyl methacrylate-comethyl methacrylate (PGMA in ethanolic – aqueous solution by heating and subsequent cooling. The PGMA monolith had topologically porous structure, which was attributed to the phase separation of the polymer solution. The PGMA monolith was impregnated by epoxidized soybean oil (ESO containing thermally-latent catalyst, and the subsequent curing produced a crosslinked material with relatively good transparency. The Young’s modulus and the tensile strength of polyESO/PGMA increased compared with the ESO homopolymer. The strain at break of polyESO/PGMA was larger than that of the ESO homopolymer and crosslinked PGMA. Furthermore, polyESO/PGMA exhibited good shape memory-recovery behavior.

  16. Novel polymer coatings based on plasma polymerized 2-methoxyethyl acrylate

    DEFF Research Database (Denmark)

    Wu, Zhenning; Jiang, Juan; Benter, Maike

    2008-01-01

    plasma system[4]. The system named SoftPlasma™ is equipped with unique three-phase pulsed AC voltage. Low energy plasma polymerization has almost no thermal load for sensitive polymer materials[5]. Plasma polymerized coatings are highly cross-linked, pin-hole free and provide hydrophilic or hydrophobic...... synthesized by Atom Transfer Radical Polymerization (ATRP)[3]. This enabled a surface segregation of the more hydrophilic block to the polymer/air interface and enrichment of the surface with PMEA. Here we present another way to modify a surface with this material - plasma polymerization in a low energy...... properties[4-6]. We have exploited these possibilities and prepared plasma polymerized 2-methoxyethyl acrylate (PPMEA) coatings on various polymer substrates. The PPMEA coatings were optimized using various plasma polymerization conditions and characterized by X-ray photoelectron spectroscopy...

  17. Characteristics and mechanisms of acrylate polymer damage to maize seedlings.

    Science.gov (United States)

    Chen, Xian; Mao, Xiaoyun; Lu, Qin; Liao, Zongwen; He, Zhenli

    2016-07-01

    Superabsorbent acrylate polymers (SAPs) have been widely used to maintain soil moisture in agricultural management, but they may cause damage to plants, and the mechanisms are not well understood. In this study, seed germination, soil pot culture, hydroponic experiments, and SAPs degradation were conducted to investigate damage characteristics and mechanisms associated with SAPs application. The Results showed that SAPs inhibited maize growth and altered root morphology (irregular and loose arrangement of cells and breakage of cortex parenchyma), and the inhibitory effects were enhanced at higher SAPs rates. After 1h SAP hydrogels treatment, root malondialdehyde (MDA) content was significantly increased, while superoxide dismutase (SOD) and catalase (CAT) content were significantly decreased. Hydroponics experiment indicated that root and shoot growth was inhibited at 2.5mgL(-1) acrylic acid (AA), and the inhibition was enhanced with increasing AA rates. This effect was exacerbated by the presence of Na(+) at a high concentration in the hydrogels. Release and degradation of AA were enhanced at higher soil moisture levels. A complete degradation of AA occurred between 15 and 20 days after incubation (DAI), but it took longer for Na(+) concentration to decrease to a safe level. These results indicate that high concentration of both AA and Na(+) present in the SAPs inhibits plant growth. The finding of this study may provide a guideline for appropriate application of SAPs in agriculture. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Mechanical modeling of interpenetrating polymer network reinforced acrylic elastomer

    Science.gov (United States)

    Schmidt, Arne; Bergamini, Andrea; Kovacs, Gabor; Mazza, Edoardo

    2010-04-01

    Interpenetrating polymer network reinforced acrylic elastomers (IPN) offer outstanding performance in free-standing contractile dielectric elastomer actuators. This work presents the verification of a recently proposed material model for a VHB 4910 based IPN [1]. The 3D large strain material model was determined from extensive data of multiaxial mechanical experiments and allows to account for the variations in material composition of IPN-membranes. We employed inflation tests to membranes of different material composition to study the materials response in a stress state different from the one that was used to extract the material parameters. By applying the material model to finite element models we successfully validated the material model in a range of material compositions typically used for dielectric elastomer actuator applications. In combination with a characterization of electro-mechanical coupling, this 3D large strain model can be used to model IPN-based dielectric elastomer actuators.

  19. Carbon fiber reinforced thermoplastic composites from acrylic polymer matrices: Interfacial adhesion and physical properties

    Directory of Open Access Journals (Sweden)

    H. Kishi

    2017-04-01

    Full Text Available Acrylic polymers have high potential as matrix polymers for carbon fiber reinforced thermoplastic polymers (CFRTP due to their superior mechanical properties and the fact that they can be fabricated at relatively low temperatures. We focused on improving the interfacial adhesion between carbon fibers (CFs and acrylic polymers using several functional monomers for co-polymerization with methyl methacrylate (MMA. The copolymerized acrylic matrices showed good adhesion to the CF surfaces. In particular, an acrylic copolymer with acrylamide (AAm showed high interfacial adhesive strength with CFs compared to pure PMMA, and a hydroxyethyl acrylamide (HEAA copolymer containing both amide and hydroxyl groups showed high flexural strength of the CFRTP. A 3 mol% HEAA-copolymerized CFRTP achieved a flexural strength almost twice that of pure PMMA matrix CFRTP, and equivalent to that of an epoxy matrix CFRP.

  20. Self-Compacting Concrete Incorporating Micro-SiO2 and Acrylic Polymer

    Directory of Open Access Journals (Sweden)

    Ali Heidari

    2014-01-01

    Full Text Available This study examined the effects of using acrylic polymer and micro-SiO2 in self-compacting concrete (SCC. Using these materials in SCC improves the characteristics of the concrete. Self-compacting samples with 1-2% of a polymer and 10% micro-SiO2 were made. In all cases, compressive strength, water absorption, and self-compacting tests were done. The results show that adding acrylic polymer and micro-SiO2 does not have a significant negative effect on the mechanical properties of self-compacting concrete. In addition using these materials leads to improving them.

  1. Polymer coating comprising 2-methoxyethyl acrylate units synthesized by surface-initiated atom transfer radical polymerization

    DEFF Research Database (Denmark)

    2011-01-01

    Source: US2012184029A The present invention relates to preparation of a polymer coating comprising or consisting of polymer chains comprising or consisting of units of 2-methoxyethyl acrylate synthesized by Surface-Initiated Atom Transfer Radical Polymerization (SI ATRP) such as ARGET SI ATRP...

  2. PHOTORESPONSIVE BEHAVIOR OF AZOBENZENE-BASED (METH)ACRYLIC (CO)POLYMERS IN THIN-FILMS

    NARCIS (Netherlands)

    HAITJEMA, HJ; VONMORGEN, GL; TAN, YY; CHALLA, G

    1994-01-01

    The reversible photoisomerization and the thermal isomerization of azobenzene-based (Az.b.) groups covalently bound to (meth)acrylic (co)polymers were investigated in thin films. For the amorphous polymers it was found that a broad range of the thermal cis --> trans isomerization rates could be

  3. Gel polymer electrolytes based on nanofibrous polyacrylonitrile–acrylate for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dul-Sun [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Woo, Jang Chang [Department of Textile Engineering, Inha University, 100 Inharo, Nam-gu Incheon 402-751 (Korea, Republic of); Youk, Ji Ho, E-mail: youk@inha.ac.kr [Department of Textile Engineering, Inha University, 100 Inharo, Nam-gu Incheon 402-751 (Korea, Republic of); Manuel, James [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of)

    2014-10-15

    Graphical abstract: - Highlights: • Nanofibrous polyacrylonitrile–acrylate membranes were prepared by electrospinning. • Trimethylolpropane triacrylate was used as a crosslinking agent of fibers. • The GPE based on PAN–acrylate (1/0.5) showed good electrochemical properties. - Abstract: Nanofibrous membranes for gel polymer electrolytes (GPEs) were prepared by electrospinning a mixture of polyacrylonitrile (PAN) and trimethylolpropane triacrylate (TMPTA) at weight ratios of 1/0.5 and 1/1. TMPTA is used to achieve crosslinking of fibers thereby improving mechanical strength. The average fiber diameters increased with increasing TMPTA concentration and the mechanical strength was also improved due to the enhanced crosslinking of fibers. GPEs based on electrospun membranes were prepared by soaking them in a liquid electrolyte of 1 M LiPF{sub 6} in ethylene carbonate (EC)/dimethyl carbonate (DMC) (1:1, v/v). The electrolyte uptake and ionic conductivity of GPEs based on PAN and PAN–acrylate (weight ratio; 1/1 and 1/0.5) were investigated. Ionic conductivity of GPEs based on PAN–acrylate was the highest for PAN/acrylate (1/0.5) due to the proper swelling of fibers and good affinity with liquid electrolyte. Both GPEs based on PAN and PAN–acrylate membranes show good oxidation stability, >5.0 V vs. Li/Li{sup +}. Cells with GPEs based on PAN–acrylate (1/0.5) showed remarkable cycle performance with high initial discharge capacity and low capacity fading.

  4. 40 CFR 721.463 - Acrylate of polymer based on isophorone diisocyanate (generic).

    Science.gov (United States)

    2010-07-01

    ... AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant... substance identified generically as acrylate of polymer based on isophorone diisocyanate (PMN P-00-0626) is... part apply to this section except as modified by this paragraph. (1) Recordkeeping. Recordkeeping...

  5. Bioinspired bioadhesive polymers: dopa-modified poly(acrylic acid) derivatives.

    Science.gov (United States)

    Laulicht, Bryan; Mancini, Alexis; Geman, Nathanael; Cho, Daniel; Estrellas, Kenneth; Furtado, Stacia; Hopson, Russell; Tripathi, Anubhav; Mathiowitz, Edith

    2012-11-01

    The one-step synthesis and characterization of novel bioinspired bioadhesive polymers that contain Dopa, implicated in the extremely adhesive byssal fibers of certain gastropods, is reported. The novel polymers consist of combinations of either of two polyanhydride backbones and one of three amino acids, phenylalanine, tyrosine, or Dopa, grafted as side chains. Dopa-grafted hydrophobic backbone polymers exhibit as much as 2.5 × the fracture strength and 2.8 × the tensile work of bioadhesion of a commercially available poly(acrylic acid) derivative as tested on live, excised, rat intestinal tissue. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Thiourea-tagged poly(octadecyl acrylate) gels as fluoride and acetate responsive polymer gels through selective complexation.

    Science.gov (United States)

    Krishnamurthi, Janakiraman; Ono, Toshikazu; Amemori, Shogo; Komatsu, Hiromu; Shinkai, Seiji; Sada, Kazuki

    2011-02-07

    Fluoride and acetate-responsive polymer gels were prepared by incorporation of p-nitrophenylthiourea into poly(octadecyl acrylate) gels, and the colours and volumes were changed selectively in the presence of these ions by complexation in THF.

  7. Tailored (meth)acrylate shape-memory polymer networks for ophthalmic applications.

    Science.gov (United States)

    Song, Li; Hu, Wang; Wang, Guojie; Niu, Guoguang; Zhang, Hongbin; Cao, Hui; Wang, Kaijie; Yang, Huai; Zhu, Siquan

    2010-10-08

    The unique features of shape-memory polymers enables their use in minimally invasive surgical procedures with a compact starting material switching over to a voluminous structure in vivo. In this work, a series of transparent, thermoset (meth)acrylate shape-memory polymer networks with tailored thermomechanics have been synthesized and evaluated. Fundamental trends were established for the effect of the crosslinker content and crosslinker molecular weight on glass transition temperature, rubbery modulus and shape-recovery behavior, and the results are intended to help with future shape-memory device design. The prepared (meth)acrylate networks with high transparency and favorable biocompatibility are presented as a promising shape-memory ophthalmic biomaterial.

  8. Development of Composite Adsorbent Coating Based Acrylic Polymer/Bentonite for Methylene Blue Removal

    OpenAIRE

    Azha, Syahida Farhan; Abd Hamid, Shazlina; Ismail, Suzylawati

    2017-01-01

    The development of composite adsorbent coating based acrylic polymer solution (APS) mixed with bentonite (ben) was investigated. The composite adsorbent coating was prepared and coated to a high surface area substrate, cotton cellulosic fiber (CCF). The APS/ben-CCF was used for a single cationic methylene blue (MB) dye adsorption system. Characterization of composition and structure of materials and coating was carried out by X-ray fluorescence (XRF), scanning electron microscopy (SEM), and U...

  9. Preparation and magnetic properties of polymer magnetic composites based on acrylate resin filled with nickel plating graphite nanosheets

    Science.gov (United States)

    Zhang, Yi; Qi, Shuhua; Zhang, Fan; Yang, Yongqing; Duan, Guochen

    2011-11-01

    Nickel plating graphite nanosheets (Ni/GNs) were prepared by electroless plating method using graphite nanosheets (GNs). Then a novel polymer magnetic composites based on acrylate pressure-sensitive adhesive (acrylate PSA) filled with Ni/GNs were fabricated by solution blend method. The Ni/GNs and acrylate PSA/Ni/GNs composites were characterized by scanning electron microscope (SEM)/energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and transmission electron microscope (TEM). All results showed that relatively uniform and compact Ni layer is successfully coated onto GNs under the given conditions, furthermore, Ni/GNs are homogeneously dispersed in acrylate PSA. The VSM results showed that the saturation magnetization of acrylate PSA/Ni/GNs composites increases with an increasing content of Ni/GNs while the coercivity decreases with an increasing content of Ni/GNs. When the content of GNs is 20 wt%, acrylate PSA/Ni/GNs composites exhibites good mechanical properties.

  10. Degradability of an Acrylate-Linked, Fluorotelomer Polymer in Soil

    Science.gov (United States)

    Fluorotelomer polymers are used in a broad array of products in modern societies worldwide and, if they degrade at significant rates, potentially are a significant source of perfluorooctanoic acid (PFOA) and related compounds to the environment. To evaluate this possibility, we i...

  11. Synthesis of Hydroxy-Terminated Dinitropropyl Acrylate Polymers.

    Science.gov (United States)

    1981-01-01

    Phthaloyl peroxide ( BPO -CO2 H) A benzoyl peroxide was selected over other acyl peroxides because it does not contain active hydrogen atoms. Active...and Characterization of Azo-OH 8 b. Attempted Synthesis of BPO -OH 11 i. Synthesis of Phthaloyl Peroxide ( BPO -CO2H) 11 ii. Attempted Synthesis of BPO ...hydrogen atoms may cause the formation of undesirable monofunctional polymers through chain transfer reactions. The precursor of BPO -OH, phthaloyl peroxide

  12. Accurate determination of residual acrylic acid in superabsorbent polymer of hygiene products by headspace gas chromatography.

    Science.gov (United States)

    Zhang, Shu-Xin; Chai, Xin-Sheng; Jiang, Ran

    2017-02-17

    This work reports on a method for the determination of residual acrylic acid (AA) in the superabsorbent polymers for hygiene products by headspace analysis. It was based on water extraction for the polymer sample at a room temperature for 50min. Then, the AA in the extractant reacted with bicarbonate solution in a closed headspace sample vial, from which the carbon dioxide generated from the reaction (within 20min at 70°C) was detected by gas chromatography (GC). It was found that there is adsorption partition equilibrium of AA between solid-liquid phases. Therefore, an equation for calculating the total AA content in the original polymers sample was derived based on the above phase equilibrium. The results show that the HS-GC method has good precision (RSD<2.51%) and good accuracy (recoveries from 93 to 105%); the limit of quantification (LOQ) was 373mg/kg. The present method is rapid, accurate, and suitable for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Properties of the acrylic acid polymers obtained by atmospheric pressure plasma polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Topala, Ionut [Plasma Physics Laboratory, Faculty of Physics, Al. I. Cuza University, 11 Carol I Boulevard, 700506 Iasi (Romania)], E-mail: itopala@plasma.uaic.ro; Dumitrascu, Nicoleta; Popa, Gheorghe [Plasma Physics Laboratory, Faculty of Physics, Al. I. Cuza University, 11 Carol I Boulevard, 700506 Iasi (Romania)

    2009-01-15

    Plasma polymers of acrylic acid were obtained using an atmospheric pressure discharge system. The plasma polymerization reactor uses a dielectric barrier discharge, with the polyethylene terephthalate dielectric acting as substrate for deposition. The plasma was characterized by specific electrical measurements, monitoring the applied voltage and the discharge current. Based on the spatially resolved optical emission spectroscopy, we analyzed the distribution of the excited species in the discharge gap, specific plasma temperatures (vibrational and gas temperatures) being calculated with the Boltzmann plot method. The properties of the plasma polymer films were investigated by contact angle measurements, infrared and UV-Vis spectroscopy, scanning electron microscopy. The films produced by plasma polymerization at atmospheric pressure showed a hydrophilic character, in correlation with the strong absorbance of OH groups in the FTIR spectrum. Moreover, the surface of the plasma polymers at micrometric scale is smooth and free of defects without particular features.

  14. Ageing phenomenon in acrylic polymer dental materials detected by means of positron annihilation lifetime spectroscopy.

    Science.gov (United States)

    Filipecki, Jacek; Chamerski, Kordian; Boyko, Olha; Kotynia, Katarzyna

    2014-01-01

    Polymer materials based on acrylic monomers are commonly used in dentistry. It is important to research the structure of dental filling materials towards the material ageing. The study has been conducted in order to determine the presence of free volume gaps in the structure of polymer materials. Brand new, acrylic polymer based samples of dental Dipol materials were used as a research material. The study was conducted by means of the positron annihilation lifetime spectroscopy (PALS). As a result of the conducted measurements, curves describing numbers of counts of the acts of annihilation in the time function were obtained. The conducted studies revealed the existence of four components τ1, τ2, τ3 and τ4. The τ3 and τ4 components are attributed to the pick-off annihilation of o-Ps orthopositronium trapping by free volume gaps and provide information about geometrical parameters of the volumes. LT 9 computer program was used to calculate components. Free volume holes were determined from empirical relationship between the radius of free volume and the long lifetime components. Conducted studies indicate the presence of free volume holes in the research materials. It has been noted that a new long lifetime component is assigned to a new kind of free volumes that exist in the structure of material related to the material ageing.

  15. Surface properties and color stability of an acrylic resin combined with an antimicrobial polymer

    Directory of Open Access Journals (Sweden)

    Ana Carolina Pero

    Full Text Available INTRODUCTION: The occurrence of stomatitis is common since the surface characteristics of the dentures may act as reservoirs for microorganisms and have the potential to support biofilm formation. PURPOSE: To assess the surface properties (wettability/roughness and color stability of an acrylic resin combined with the antimicrobial polymer poly (2-tert-butylaminoethyl methacrylate (PTBAEMA. MATERIAL AND METHOD: Thirty disc-shaped specimens of an acrylic resin (Lucitone 550 were divided into three groups: 0% (control; 5% and 10% PTBAEMA. Surface roughness values (Ra were measured using a profilometer and wettability was determined through contact angle measurements using a goniometer and deionized water as a test liquid. Color data were measured with a spectrophotometer. Kruskal-Wallis and Dunn's test were used to compare roughness values. Wettability data were analyzed using ANOVA and Tukey's test. Color data were compared using the Student's t-test and ∆E values were classified according to the National Bureau of Standards (NBS. All statistical analyses were performed considering α=.05. RESULT: Significant differences (p<.05 were detected among the groups for roughness, wettability and color stability. According to the NBS, the color changes obtained in the 5% and 10% PTBAEMA groups were "appreciable" and "much appreciable", respectively. CONCLUSION: It could be concluded that PTBAEMA incorporation in an acrylic resin increased the roughness and wettability of surfaces and produced color changes with clinical relevance.

  16. Adhesive retention of experimental fiber-reinforced composite, orthodontic acrylic resin, and aliphatic urethane acrylate to silicone elastomer for maxillofacial prostheses.

    Science.gov (United States)

    Kosor, Begüm Yerci; Artunç, Celal; Şahan, Heval

    2015-07-01

    A key factor of an implant-retained facial prosthesis is the success of the bonding between the substructure and the silicone elastomer. Little has been reported on the bonding of fiber reinforced composite (FRC) to silicone elastomers. Experimental FRC could be a solution for facial prostheses supported by light-activated aliphatic urethane acrylate, orthodontic acrylic resin, or commercially available FRCs. The purpose of this study was to evaluate the bonding of the experimental FRC, orthodontic acrylic resin, and light-activated aliphatic urethane acrylate to a commercially available high-temperature vulcanizing silicone elastomer. Shear and 180-degree peel bond strengths of 3 different substructures (experimental FRC, orthodontic acrylic resin, light-activated aliphatic urethane acrylate) (n=15) to a high-temperature vulcanizing maxillofacial silicone elastomer (M511) with a primer (G611) were assessed after 200 hours of accelerated artificial light-aging. The specimens were tested in a universal testing machine at a cross-head speed of 10 mm/min. Data were collected and statistically analyzed by 1-way ANOVA, followed by the Bonferroni correction and the Dunnett post hoc test (α=.05). Modes of failure were visually determined and categorized as adhesive, cohesive, or mixed and were statistically analyzed with the chi-squared goodness-of-fit test (α=.05). As the mean shear bond strength values were evaluated statistically, no difference was found among the experimental FRC, aliphatic urethane acrylate, and orthodontic acrylic resin subgroups (P>.05). The mean peel bond strengths of experimental fiber reinforced composite and aliphatic urethane acrylate were not found to be statistically different (P>.05). The mean value of the orthodontic acrylic resin subgroup peel bond strength was found to be statistically lower (P.05). Shear forces predominantly exhibited cohesive failure (64.4%), whereas peel forces predominantly exhibited adhesive failure (93.3%). The

  17. Preparation and properties of UV-cured acrylated silane intercalated polymer/LDH nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Yan [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230026 (China); Shi, Wenfang, E-mail: wfshi@ustc.edu [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230026 (China)

    2011-01-15

    A novel UV-cured polymer/layered double hydroxide (LDH) nanocomposite was prepared by modifying the LDH with sodium dodecyl sulfate (SDS) and [3-(methyl-acroloxy)propyl]trimethoxysilane (KH570) followed by UV irradiation after blended into a acrylate system. From the XRD analyses, the SDS-modified LDH-DS presented the basal spacing of 2.67 nm, whereas the further KH570-intercalated LDH-KH showed a slight decrease to 2.41 nm. After UV irradiated the exfoliated microstructure was formed, and observed by TEM and HR-TEM, showing the fine dispersion and random orientation of LDH in the polymer matrix. The storage modulus and glass transition temperature of the nanocomposite containing 5% LDH-KH increased to 47.5 MPa and 67.8 {sup o}C, respectively, from 39.7 MPa and 66 {sup o}C of the pure polymer from DMTA measurements. The tensile strength and Persoz hardness were enhanced to 10.6 MPa and 111 s, respectively, from 7.7 MPa and 85 s of the pure polymer.

  18. ABS polymer electroless plating through a one-step poly(acrylic acid) covalent grafting.

    Science.gov (United States)

    Garcia, Alexandre; Berthelot, Thomas; Viel, Pascal; Mesnage, Alice; Jégou, Pascale; Nekelson, Fabien; Roussel, Sébastien; Palacin, Serge

    2010-04-01

    A new, efficient, palladium- and chromium-free process for the electroless plating of acrylonitrile-butadiene-styrene (ABS) polymers has been developed. The process is based on the ion-exchange properties of poly(acrylic acid) (PAA) chemically grafted onto ABS via a simple and one-step method that prevents using classical surface conditioning. Hence, ABS electroless plating can be obtained in three steps, namely: (i) the grafting of PAA onto ABS, (ii) the copper Cu(0) seeding of the ABS surface, and (iii) the nickel or copper metallization using commercial-like electroless plating bath. IR, XPS, and SEM were used to characterize each step of the process, and the Cu loading was quantified by atomic absorption spectroscopy. This process successfully compares with the commercial one based on chromic acid etching and palladium-based seed layer, because the final metallic layer showed excellent adhesion with the ABS substrate.

  19. Electrical, dielectric and electrochemical characterization of novel poly(acrylic acid)-based polymer electrolytes complexed with lithium tetrafluoroborate

    Science.gov (United States)

    Ngai, Koh Sing; Ramesh, S.; Ramesh, K.; Juan, Joon Ching

    2018-01-01

    A series of novel poly(acrylic acid)-based polymer electrolytes with high conductivities at room temperature has been prepared and studied. Polymer electrolytes composed of poly(acrylic acid) (PAA) and lithium tetrafluoroborate (LiBF4) were prepared by means of solution casting. The effect of the addition of LiBF4 on the properties of the PAA-based electrolyte matrices was analysed and investigated using impedance spectroscopy. The optimized PAA-based solid electrolyte showed an electrochemical stability window of 3.2 V. Thermogravimetric analysis indicated that the incorporation of LiBF4 into PAA matrix enhances the thermal stability. The structural properties of polymer electrolytes were studied by using X-ray diffraction analysis.

  20. Development and characterization of adjustable refractive index scattering epoxy acrylate polymer layers

    Science.gov (United States)

    Eiselt, Thomas; Preinfalk, Jan; Gleißner, Uwe; Lemmer, Uli; Hanemann, Thomas

    2017-03-01

    Several polymer films for improved optical properties in optoelectronic devices are presented. In such optical applications, it is sometimes important to have a film with an adjusted refractive index, scattering properties, and a low surface roughness. These diffusing films can be used to increase the efficiency of optoelectronic components, such as organic light-emitting diodes. Three different epoxy acrylate mixtures containing Syntholux 291 EA, bisphenol A glycerolate dimethacrylate, and Sartomer SR 348 L are characterized and optimized with different additives. The adjustable refractive index of the material is achieved by chemical doping using 9-vinylcarbazole. Titanium nanoparticles in the mixtures generate light scattering and increase the refractive index additionally. A high-power stirrer is used to mix and disperse all chemical substances together to a homogenous mixture. The viscosity behavior of the mixtures is an important property for the selection of the production method and, therefore, the viscosity measurement results are presented. After the mixing, the monomer mixture is applied on glass substrates by screen printing. To initiate polymerization, the produced films are irradiated for 10 min with ultraviolet radiation and heat. Transmission measurements of the polymer matrix and roughness measurements complement the characterization.

  1. Regulation of the Contribution of Integrin to Cell Attachment on Poly(2-Methoxyethyl Acrylate (PMEA Analogous Polymers for Attachment-Based Cell Enrichment.

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    Takashi Hoshiba

    Full Text Available Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate (PMEA substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate (PBA and poly(tetrahydrofurfuryl acrylate (PTHFA, on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy ethyl acrylate-co-butyl acrylate (30:70 mol%, PMe2A and poly(2-(2-methoxyethoxy ethoxy ethyl acrylate-co-butyl acrylate (30:70 mol%, PMe3A, which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment.

  2. Regulation of the Contribution of Integrin to Cell Attachment on Poly(2-Methoxyethyl Acrylate) (PMEA) Analogous Polymers for Attachment-Based Cell Enrichment.

    Science.gov (United States)

    Hoshiba, Takashi; Nemoto, Eri; Sato, Kazuhiro; Orui, Toshihiko; Otaki, Takayuki; Yoshihiro, Ayano; Tanaka, Masaru

    2015-01-01

    Cell enrichment is currently in high demand in medical engineering. We have reported that non-blood cells can attach to a blood-compatible poly(2-methoxyethyl acrylate) (PMEA) substrate through integrin-dependent and integrin-independent mechanisms because the PMEA substrate suppresses protein adsorption. Therefore, we assumed that PMEA analogous polymers can change the contribution of integrin to cell attachment through the regulation of protein adsorption. In the present study, we investigated protein adsorption, cell attachment profiles, and attachment mechanisms on PMEA analogous polymer substrates. Additionally, we demonstrated the possibility of attachment-based cell enrichment on PMEA analogous polymer substrates. HT-1080 and MDA-MB-231 cells started to attach to poly(butyl acrylate) (PBA) and poly(tetrahydrofurfuryl acrylate) (PTHFA), on which proteins could adsorb well, within 1 h. HepG2 cells started to attach after 1 h. HT-1080, MDA-MB-231, and HepG2 cells started to attach within 30 min to PMEA, poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe2A) and poly(2-(2-methoxyethoxy) ethoxy ethyl acrylate-co-butyl acrylate) (30:70 mol%, PMe3A), which suppress protein adsorption. Moreover, the ratio of attached cells from a cell mixture can be changed on PMEA analogous polymers. These findings suggested that PMEA analogous polymers can be used for attachment-based cell enrichment.

  3. Synthesis and Characterization of Shape Memory (Meth)Acrylate Co-Polymers and their Cytocompatibility In Vitro.

    Science.gov (United States)

    Song, Li; Hu, Wang; Wang, Guojie; Zhang, Hongbin; Niu, Guoguang; Cao, Hui; Yang, Huai; Zhu, Siquan

    2011-01-01

    A series of novel transparent shape memory co-polymers, made from (meth)acrylate monomers, intended to be used as intraocular lens, was synthesized. The thermo-mechanical properties, shape memory properties and optical properties of the co-polymers could be adjusted by using monomers with various alkyl chain lengths. The cytocompatibility of the prepared co-polymers to L929 mouse connective tissue fibroblasts was demonstrated in vitro, and the co-polymers exhibited favorable cytocompatibility, supporting cell viability and proliferation. This study showed that the prepared co-polymers, which exhibited good flexibility, adjustable shape memory properties, high transparency and favorable cytocompatibility, could find great promising applications as intraocular lens.

  4. Shape Memory Polymers Containing Higher Acrylate Content Display Increased Endothelial Cell Attachment

    Directory of Open Access Journals (Sweden)

    Tina Govindarajan

    2017-11-01

    Full Text Available Shape Memory Polymers (SMPs are smart materials that can recall their shape upon the application of a stimulus, which makes them appealing materials for a variety of applications, especially in biomedical devices. Most prior SMP research has focused on tuning bulk properties; studying surface effects of SMPs may extend the use of these materials to blood-contacting applications, such as cardiovascular stents, where surfaces that support rapid endothelialization have been correlated to stent success. Here, we evaluate endothelial attachment onto the surfaces of a family of SMPs previously developed in our group that have shown promise for biomedical devices. Nine SMP formulations containing varying amounts of tert-Butyl acrylate (tBA and Poly(ethylene glycol dimethacrylate (PEGDMA were analyzed for endothelial cell attachment. Dynamic mechanical analysis (DMA, contact angle studies, and atomic force microscopy (AFM were used to verify bulk and surface properties of the SMPs. Human umbilical vein endothelial cell (HUVEC attachment and viability was verified using fluorescent methods. Endothelial cells preferentially attached to SMPs with higher tBA content, which have rougher, more hydrophobic surfaces. HUVECs also displayed an increased metabolic activity on these high tBA SMPs over the course of the study. This class of SMPs may be promising candidates for next generation blood-contacting devices.

  5. Development of Composite Adsorbent Coating Based Acrylic Polymer/Bentonite for Methylene Blue Removal

    Directory of Open Access Journals (Sweden)

    Syahida Farhan Azha

    2017-07-01

    Full Text Available The development of composite adsorbent coating based acrylic polymer solution (APS mixed with bentonite (ben was investigated. The composite adsorbent coating was prepared and coated to a high surface area substrate, cotton cellulosic fiber (CCF. The APS/ben-CCF was used for a single cationic methylene blue (MB dye adsorption system. Characterization of composition and structure of materials and coating was carried out by X-ray fluorescence (XRF, scanning electron microscopy (SEM, and UV-spectroscopy (UV-VIS. The adsorption properties of the APS/ben-CCF were investigated as a function of solution pH, initial dye concentration and contact time as well as solution temperature of MB dye. The result revealed that the APS/ben-CCF functioned well in solutions of various pH (acidic to alkaline, achieving 100% removal of MB within 2 hours of adsorption for 50 ppm. Kinetic studies showed that APS/ben-CCF is endothermic in nature since the adsorption capacity increased with increasing solution temperature. These results demonstrate that APS/ben-CCF composite adsorbent coating is an advanced adsorbent with advantages such as easy phase separation and capability to remove cationic dyes in a short time period.

  6. Development and characterization of adjustable refractive index scattering epoxy acrylate polymer layers

    Science.gov (United States)

    Eiselt, Thomas; Preinfalk, Jan; Gleißner, Uwe; Lemmer, Uli; Hanemann, Thomas

    2016-09-01

    This work presents different polymer diffusing films for optical components. In optical applications it is sometimes important to have a film with an adjusted refractive index, scattering properties and a low surface roughness. These diffusing films can be used to increase the efficiency of optical components like organic light emitting diodes (OLEDs). In this study three different epoxy acrylate mixtures containing Syntholux 291 EA, bisphenol a glycerolate dimethacrylate, Sartomer SR 348 L are characterized and optimized with different additives. The adjustable refractive index of the material is achieved with a chemical doping by 9-vinylcarbazole. Titanium nanoparticles in the mixtures generate light scattering and increase the refractive index additionally. To prevent sedimentation and agglomeration of these nanoparticles, a stabilization agent [2-(2-methoxyethoxy)ethoxy]acetic acid is added to the mixture. Other ingredients are a UV-starter and thermal starter for the radical polymerization. A high power stirrer (ultraturrax) is used to mix and disperse all chemical substances together to a homogenous mixture. The viscosity behavior of the mixtures is an important property for the selection of the production method and gets characterized. After the mixing, the monomer mixture is applied on glass substrates by blade coating or screen printing. To initiate the chain growing (polymerization) the produced films are irradiated for 10 minutes long with UV light (UV LED Spot Hönle, 405 nm). After this step a final post bake from the layers in the oven (150°C, 30 min.) is operated. Light transmission measurements (UV-Vis) of the polymer matrix and roughness measurements complement the characterization.

  7. Silicone/Acrylate Copolymers

    Science.gov (United States)

    Dennis, W. E.

    1982-01-01

    Two-step process forms silicone/acrylate copolymers. Resulting acrylate functional fluid is reacted with other ingredients to produce copolymer. Films of polymer were formed by simply pouring or spraying mixture and allowing solvent to evaporate. Films showed good weatherability. Durable, clear polymer films protect photovoltaic cells.

  8. Nano-emulsion based on acrylic acid ester co-polymer derivatives as an efficient pre-tanning agent for buffalo hide

    Directory of Open Access Journals (Sweden)

    Farouk Abd El-Monem

    2017-05-01

    Full Text Available Acrylic copolymer nanoemulsions were prepared based on methyl methacrylate (MMA and butyl acrylate (BA. The prepared acrylic copolymer emulsions were characterized using solid content, rheological properties, molecular weight, MFFT and TEM. The prepared polymers were used as pre-tanning of the depickled hide to enhance the physico-mechanical properties of tanned leather. The key parameters which affect exhaustion and fixation of chrome tan as well as shrinkage temperature of the tanned leather were studied and evaluated using SEM, shrinkage temperature and the mechanical properties of the pre-tanned leather. The results showed that, the prepared polymers A & C are the best polymers in improving the physical properties of the treated leather. Furthermore, the shrinkage temperature and the mechanical properties of the tanned leather were improved. In addition, a significant enhancement in the texture of the leather treated by the polymers was noticed as proved by scanning electron microscopy (SEM.

  9. In Situ Nitroxide-Mediated Polymerized Poly(acrylic acid as a Stabilizer/Compatibilizer Carbon Nanotube/Polymer Composites

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    Vitaliy Datsyuk

    2007-01-01

    the opportunity to reinitiate the polymerization of a second block that can be chosen among a wide range of monomers. This versatility is illustrated with a second block containing methyl acrylate (MA or styrene (S. Scanning and transmission electron microscopies confirm good CNT dispersion in the polymer network, while transmission electron microscopy also spots the anchorage locations of PAA on the CNT surface. Such nanotubes wrapped by diblock copolymers can be dispersed in various polymer matrices to create CNT—polymer composites. Conductivity measurements show that these composites obey a percolation-like power law with a low percolation threshold (less than 0.5 vol% and a high maximum conductivity (up to 1.5 S/cm at room temperature.

  10. Characterizing Effects of Nitric Oxide Sterilization on tert-Butyl Acrylate Shape Memory Polymers

    Science.gov (United States)

    Phillippi, Ben

    As research into the potential uses of shape memory polymers (SMPs) as implantable medical devices continues to grow and expand, so does the need for an accurate and reliable sterilization mechanism. The ability of an SMP to precisely undergo a programmed shape change will define its ability to accomplish a therapeutic task. To ensure proper execution of the in vivo shape change, the sterilization process must not negatively affect the shape memory behavior of the material. To address this need, this thesis investigates the effectiveness of a benchtop nitric oxide (NOx) sterilization process and the extent to which the process affects the shape memory behavior of a well-studied tert-Butyl Acrylate (tBA) SMP. Quantifying the effects on shape memory behavior was performed using a two-tiered analysis. A two-tiered study design was used to determine if the sterilization process induced any premature shape recovery and to identify any effects that NOx has on the overall shape memory behavior of the foams. Determining the effectiveness of the NOx system--specially, whether the treated samples are more sterile/less contaminated than untreated--was also performed with a two-tiered analysis. In this case, the two-tiered analysis was employed to have a secondary check for contamination. To elaborate, all of the samples that were deemed not contaminated from the initial test were put through a second sterility test to check for contamination a second time. The results of these tests indicated the NOx system is an effective sterilization mechanism and the current protocol does not negatively impact the shape memory behavior of the tBA SMP. The samples held their compressed shape throughout the entirety of the sterilization process. Additionally, there were no observable impacts on the shape memory behavior induced by NOx. Lastly, the treated samples demonstrated lower contamination than the untreated. This thesis demonstrates the effectiveness of NOx as a laboratory scale

  11. Kinetics and mechanism of polymer dispersion formation on based of (meth)acrylates. Part 2

    OpenAIRE

    GOLDFEIN M.D.; KOZHEVNIKOV N.V.; KOZHEVNIKOVA N.I.; ZAIKOV G.E.

    2015-01-01

    The aim of the present work was to establish the kinetics and mechanism of joint emulsion polymerization of methyl acrylate with metacrylic acid (MAA) or acrylonitrile, which underlies production of many commercial acrylic polymeric dispersions. The emulsion polymerization of methyl methacrylate (MMA) and copolymers with acrylonitrile (AN) and methacrylic acid (MAA) was studied. Also some aspects of kinetics and mechanism of polymeric latexes formation processes in absence of emulsifier were ...

  12. Preparation and drug-loading properties of Fe{sub 3}O{sub 4}/Poly(styrene-co-acrylic acid) magnetic polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wensheng [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Coordination Chemistry Institute, School of Chemistry and Chemical Engineering and Life Science, Chaohu University, Chaohu 238000 (China); Shen, Yuhua, E-mail: s_yuhua@163.com [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Xie, Anjian [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Zhang, Weiqiang [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Coordination Chemistry Institute, School of Chemistry and Chemical Engineering and Life Science, Chaohu University, Chaohu 238000 (China)

    2013-11-15

    Fe{sub 3}O{sub 4}/poly(styrene-co-acrylic acid) magnetic polymer nanocomposites were synthesized by the dispersion polymerization method using styrene as hard monomer, acrylic acid as functional monomer, Fe{sub 3}O{sub 4} nanoparticles modified with oleic acid as core, and poly(styrene-co-acrylic acid) as shell. Drug-loading properties of magnetic polymer nanocomposites with curcumin as a model drug were also studied. The results indicated that magnetic polymer nanocomposites with monodisperse were obtained, the particle size distribution was 50–120 nm, and the average size was about 100 nm. The contents of poly(styrene-co-acrylic acid) and Fe{sub 3}O{sub 4} nanoparticles in magnetic polymer nanocomposites were 74% and 24.7%, respectively. The drug-loading capacity and entrapment efficiency were 2.5% and 44.4%, respectively. The saturation magnetization of magnetic polymer nanocomposites at 300 K was 20.2 emu/g without coercivity and remanence. The as-prepared magnetic polymer nanocomposites have not only lots of functional carboxyl groups but also stronger magnetic response, which might have potential applications in drug carrier and targeted drug release.

  13. Dewetting acrylic polymer films with water/propylene carbonate/surfactant mixtures - implications for cultural heritage conservation.

    Science.gov (United States)

    Baglioni, M; Montis, C; Brandi, F; Guaragnone, T; Meazzini, I; Baglioni, P; Berti, D

    2017-09-13

    The removal of hydrophobic polymer films from surfaces is one of the top priorities of modern conservation science. Nanostructured fluids containing water, good solvents for polymers, either immiscible or partially miscible with water, and surfactants have been used in the last decade to achieve controlled removal. The dewetting of the polymer film is often an essential step to achieve efficient removal; however, the role of the surfactant throughout the process is yet to be fully understood. We report on the dewetting of a methacrylate/acrylate copolymer film induced by a ternary mixture of water, propylene carbonate (PC) and C 9-11 E 6 , a nonionic alcohol ethoxylate surfactant. The fluid microstructure was characterised through small angle X-ray scattering and the interactions between the film and water, water/PC and water/PC/C 9-11 E 6 , were monitored through confocal laser-scanning microscopy (CLSM) and analised both from a thermodynamic and a kinetic point of view. The presence of a surfactant is a prerequisite to induce dewetting of μm-thick films at room temperature, but it is not a thermodynamic driver. The amphiphile lowers the interfacial energy between the phases and favors the loss of adhesion of the polymer on glass, decreasing, in turn, the activation energy barrier, which can be overcome by the thermal fluctuations of polymer film stability, initiating the dewetting process.

  14. Study of n-Butyl Acrylate Self-Initiation Reaction Experimentally and via Macroscopic Mechanistic Modeling

    Directory of Open Access Journals (Sweden)

    Ahmad Arabi Shamsabadi

    2016-04-01

    Full Text Available This paper presents an experimental study of the self-initiation reaction of n-butyl acrylate (n-BA in free-radical polymerization. For the first time, the frequency factor and activation energy of the monomer self-initiation reaction are estimated from measurements of n-BA conversion in free-radical homo-polymerization initiated only by the monomer. The estimation was carried out using a macroscopic mechanistic mathematical model of the reactor. In addition to already-known reactions that contribute to the polymerization, the model considers a n-BA self-initiation reaction mechanism that is based on our previous electronic-level first-principles theoretical study of the self-initiation reaction. Reaction rate equations are derived using the method of moments. The reaction-rate parameter estimates obtained from conversion measurements agree well with estimates obtained via our purely-theoretical quantum chemical calculations.

  15. Chelating compounds as potential flash rust inhibitors and melamine & aziridine cure of acrylic colloidal unimolecular polymers (CUPs)

    Science.gov (United States)

    Mistry, Jigar Kishorkumar

    Waterborne coatings on ferrous substrates usually show flash rusting which decreases the adhesion of the coating and the corrosion products can form a stain. Chelating compounds were investigated as potential flash rust inhibitors. Compounds being evaluated include amine alcohols, diamines and sulfur containing amines. A new corrosion inhibitor 2,5-bis(thioaceticacid)-1,3,4-thiadiazole (H2ADTZ) was synthesized and its performance characteristics were evaluated. It was noted that the observed structure of 1,3,4-thiadiazolidine-2,5-dithione (also known as 2,5-dimercapto-1,3,4-thiadiazole (DMTD or DMcT)) has been previously reported in three different tautomeric forms including -dithiol and -dithione. The relative stability of each form as well as the synthesis and characterization of the structures of mono- and dialkylated forms of 5-mercapto-1,3,4-thiadiazole-2(3H)-thione (MTT) were examined. The methods of X-ray crystallography, NMR spectroscopy and ab-initio electronic structure calculations were combined to understand the reactivity and structure of each compound. Polymers were synthesized with a 1:7 or 1:8 ratio of acrylic acid to acrylate monomers to produce an acid rich resin. The polymers were reduced and solvent stripped to produce Colloidal Unimolecular Polymers (CUPs). These particles are typically 3-9 nanometers in diameter depending upon the molecular weight. They were then formulated into a clear coating with either a melamine (bake) or an aziridine (ambient cure) and then cured. The melamine system was solvent free, a near zero VOC and the aziridine system was very low to near zero VOC. The coatings were evaluated for their MEK resistance, adhesion, hardness, gloss, flexibility, wet adhesion, abrasion and impact resistance properties.

  16. Two Players Make a Formidable Combination: In Situ Generated Poly(acrylic anhydride-2-methyl-acrylic acid-2-oxirane-ethyl ester-methyl methacrylate) Cross-Linking Gel Polymer Electrolyte toward 5 V High-Voltage Batteries.

    Science.gov (United States)

    Ma, Yue; Ma, Jun; Chai, Jingchao; Liu, Zhihong; Ding, Guoliang; Xu, Gaojie; Liu, Haisheng; Chen, Bingbing; Zhou, Xinhong; Cui, Guanglei; Chen, Liquan

    2017-11-29

    Electrochemical performance of high-voltage lithium batteries with high energy density is limited because of the electrolyte instability and the electrode/electrolyte interfacial reactivity. Hence, a cross-linking polymer network of poly(acrylic anhydride-2-methyl-acrylic acid-2-oxirane-ethyl ester-methyl methacrylate) (PAMM)-based electrolyte was introduced via in situ polymerization inspired by "shuangjian hebi", which is a statement in a traditional Chinese Kungfu story similar to the synergetic effect of 1 + 1 > 2. A poly(acrylic anhydride) and poly(methyl methacrylate)-based system is very promising as electrolyte materials for lithium-ion batteries, in which the anhydride and acrylate groups can provide high voltage resistance and fast ionic conductivity, respectively. As a result, the cross-linking PAMM-based electrolyte possesses a significant comprehensive enhancement, including electrochemical stability window exceeding 5 V vs Li+/Li, an ionic conductivity of 6.79 × 10-4 S cm-1 at room temperature, high mechanical strength (27.5 MPa), good flame resistance, and excellent interface compatibility with Li metal. It is also demonstrated that this gel polymer electrolyte suppresses the negative effect resulting from dissolution of Mn2+ ions at 25 and 55 °C. Thus, the LiNi0.5Mn1.5O4/Li and LiNi0.5Mn1.5O4/Li4Ti5O12 cells using the optimized in situ polymerized cross-linking PAMM-based gel polymer electrolyte deliver stable charging/discharging profiles and excellent rate performance at room temperature and even at 55 °C. These findings suggest that the cross-linking PAMM is an intriguing candidate for 5 V class high-voltage gel polymer electrolyte toward high-energy lithium-on batteries.

  17. Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC).

    Science.gov (United States)

    Ritter, Helmut; Tabatabai, Monir; Herrmann, Markus

    2016-01-01

    We describe the synthesis of bromo-tert-butyloxycarbonyl (Br-t-BOC)-amino-protected monomers 2-((1-bromo-2-methylpropan-2-yl)oxycarbonylamino)ethyl (meth)acrylate 3a,b. For this purpose, 2-isocyanatoethyl (meth)acrylate 1a,b was reacted with 1-bromo-2-methylpropan-2-ol (2a). The free radical polymerization of (Br-t-BOC)-aminoethyl (meth)acrylates 3a,b yielded poly((Br-t-BOC)-aminoethyl (meth)acrylate) 6a,b bearing protected amino side groups. The subsequent solvolysis of the Br-t-BOC function led to the new polymers poly(2-aminoethyl (meth)acrylate) 8a,b with protonated free amino groups. The monomers and the resulting polymers were thoroughly characterized by (1)H NMR, IR, GPC and DSC methods. The kinetics of the deprotection step was followed by (1)H NMR spectroscopy. The solvent polarity and neighboring group effects on the kinetics of deprotection are discussed.

  18. The influence of polymer topology on pharmacokinetics: differences between cyclic and linear PEGylated poly(acrylic acid) comb polymers.

    Science.gov (United States)

    Chen, Bo; Jerger, Katherine; Fréchet, Jean M J; Szoka, Francis C

    2009-12-16

    Water-soluble polymers for the delivery of chemotherapeutic drugs passively target solid tumors as a consequence of reduced renal clearance and the enhanced permeation and retention (EPR) effect. Elimination of the polymers in the kidney occurs due to filtration through biological nanopores with a hydrodynamic diameter comparable to the polymer. Therefore we have investigated chemical features that may broadly be grouped as "molecular architecture" such as: molecular weight, chain flexibility, number of chain ends and branching, to learn how they impact polymer elimination. In this report we describe the synthesis of four pairs of similar molecular weight cyclic and linear polyacrylic acid polymers grafted with polyethylene glycol (23, 32, 65, 114 kDa) with low polydispersities using ATRP and "click" chemistry. The polymers were radiolabeled with (125)I and their pharmacokinetics and tissue distribution after intravenous injection were determined in normal and C26 adenocarcinoma tumored BALB/c mice. Cyclic polymers above the renal threshold of 30 kDa had a significantly longer elimination time (between 10 and 33% longer) than did the comparable linear polymer (for the 66 kDa cyclic polymer, t(1/2,beta)=35+/-2 h) and a greater area under the serum concentration versus time curve. This resulted in a greater tumor accumulation of the cyclic polymer than the linear polymer counterpart. Thus water-soluble cyclic comb polymers join a growing list of polymer topologies that show greatly extended circulation times compared to their linear counterparts and provide alternative polymer architecture for use as drug carriers.

  19. Acrylate-endcapped polymer precursors: effect of chemical composition on the healing efficiency of active concrete cracks

    Science.gov (United States)

    Araújo, Maria; Van Tittelboom, Kim; Dubruel, Peter; Van Vlierberghe, Sandra; De Belie, Nele

    2017-05-01

    The repair of cracks in concrete is an unavoidable practice since these cracks endanger the durability of the structure. Inspired by nature, the self-healing concept has been widely investigated in concrete as a promising solution to solve the limitations of manual repair. This self-healing functionality may be realized by the incorporation of encapsulated healing agents in concrete. Depending on the nature of the cracks, different healing agents can be used. For structures subjected to repeated loads, elastic materials should be considered to cope with the crack opening and closing movement. In this study, various acrylate-endcapped polymer precursors were investigated for their suitability to heal active cracks. The strain capacity of the polymers was assessed by means of visual observation together with water flow tests after widening of the healed cracks in a stepwise manner. A strain of at least 50% could be sustained by epoxy- and siloxane-based healing agents. For polyester- and urethane/poly(propylene glycol)-based precursors, failure occurred at 50% elongation due to detachment of the polymer from the crack walls. However, for urethane/poly(propylene glycol)-based healing agent, debonding was limited to some local spots. The resistance of the polymerized healing agents against degradation in the strong alkaline environment characteristic for concrete has also been evaluated, with the urethane/poly(propylene glycol)-based precursor showing the best performance to withstand degradation.

  20. Preparation of hybrid thiol-acrylate emulsion-templated porous polymers by interfacial copolymerization of high internal phase emulsions.

    Science.gov (United States)

    Langford, Caitlin R; Johnson, David W; Cameron, Neil R

    2015-05-01

    Emulsion-templated highly porous polymers (polyHIPEs), containing distinct regions differing in composition, morphology, and/or properties, are prepared by the simultaneous polymerization of two high internal phase emulsions (HIPEs) contained within the same mould. The HIPEs are placed together in the mould and subjected to thiol-acrylate photopolymerization. The resulting polyHIPE material is found to contain two distinct semicircular regions, reflecting the composition of each HIPE. The original interface between the two emulsions becomes a copolymerized band between 100 and 300 μm wide, which is found to be mechanically robust. The separate polyHIPE layers are distinguished from one another by their differing average void diameter, chemical composition, and extent of contraction upon drying. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Printing continuously graded interpenetrating polymer networks of acrylate/epoxy by manipulating cationic network formation during stereolithography

    Directory of Open Access Journals (Sweden)

    W. Li

    2016-12-01

    Full Text Available Ultra-violet (UV laser assisted stereolithography is used to print graded interpenetrating polymer networks (IPNs by controlling network formation. Unlike the traditional process where structural change in IPNs is achieved by varying the feeding ratio of monomers or polymer precursors, in this demonstration property is changed by controlled termination of network formation. A photo-initiated process is used to construct IPNs by a combination of radical and cationic network formation in an acrylate/epoxy system. The extent of the cationic network formation is used to control the final properties of the system. Rapid-Scan Fourier Transformation Infrared Spectroscopy (RS-FTIR is used to track the curing kinetics of the two networks and identify key parameters to control the final properties. Atomic force microscopy (AFM and differential scanning calorimetry (DSC confirm the formation of homogenous IPNs, whereas nano-indentation indicates that properties vary with the extent of cationic network formation. The curing characteristics are used to design and demonstrate printing of graded IPNs that show two orders of magnitude variation in mechanical properties in the millimeter scale.

  2. Development and characterization of high refractive index and high scattering acrylate polymer layers

    Science.gov (United States)

    Eiselt, Thomas; Gomard, Guillaume; Preinfalk, Jan; Gleißner, Uwe; Lemmer, Uli; Hanemann, Thomas

    2016-11-01

    In this work, we develop a wet-processable scattering layer exhibiting a high refractive index that can be used in organic light-emitting diodes for light outcoupling purposes. The composite layers contain an acrylate casting resin, benzylmethacrylate, and phenanthrene, which is employed to increase the refractive index. The mixtures are first rheologically characterized and then polymerized with heat and UV radiation. For the refractive index measurements, the polymerized samples require a planar surface without air bubbles. To produce flat samples, a special construction consisting of a glass plate, a teflon sheet, a silicone ring (PDMS mold), another teflon sheet, and another glass plate is developed. Glue clamps are used to hold the construction together. The refractive index of the samples can be increased from 1.565 to 1.585 at 20°C at a wavelength of 589 nm following the addition of 20 wt% phenanthrene. A master mixture with a high refractive index is taken for further experiments. Nanoscaled titanium dioxide is added and dispersed into the master mixture and then spin coated on a glass substrate. These layers are optically characterized. Most of the presented layers present the expected haze of over 50%.

  3. Compatibilization efficiency of carboxylated nitrile rubber and epoxy pre-polymer in nitrile/acrylic rubber blends

    Directory of Open Access Journals (Sweden)

    Micheli L. Celestin

    2013-01-01

    Full Text Available An investigation has been made of the effects from a compatibilizer, viz. carboxylated nitrile rubber (XNBR, on several properties of nitrile rubber (NBR and acrylic rubber (ACM blends, including curing characteristics, mechanical, dynamic mechanical and dielectric properties. The presence of XNBR until 10 phr resulted in an improvement of the ultimate tensile properties, especially elongation at break. The mechanical properties associated to the volume fraction of rubber in the network (Vr and torque values suggest the co-vulcanization phenomenon imparted by the compatibilization. The oil resistance of NBR/ACM (50:50 wt. (% blends (compatibilized and non compatibilized was similar to that observed for pure ACM and significantly higher than NBR. The addition of small amounts of epoxy pre-polymer in combination with XNBR resulted in an additional improvement of the tensile properties. The dynamic mechanical and dielectric properties of the blends were also investigated. The loss modulus values of the compatibilized blends were significantly lower indicating an increase of the elastic characteristics. All blends presented two dielectric relaxation peaks confirming the heterogeneity of the compatibilized blends

  4. Shape Memory Polymers Containing Higher Acrylate Content Display Increased Endothelial Cell Attachment

    OpenAIRE

    Tina Govindarajan; Robin Shandas

    2017-01-01

    Shape Memory Polymers (SMPs) are smart materials that can recall their shape upon the application of a stimulus, which makes them appealing materials for a variety of applications, especially in biomedical devices. Most prior SMP research has focused on tuning bulk properties; studying surface effects of SMPs may extend the use of these materials to blood-contacting applications, such as cardiovascular stents, where surfaces that support rapid endothelialization have been correlated to stent ...

  5. IMPROVING OF RECLAIMED ASPHALT PAVEMENTS USING STYRENE-BUTYL ACRYLATE POLYMER

    OpenAIRE

    Abdelzaher E. A. Mostafa; Nasser, A M

    2017-01-01

    According to the most recent surveys, the European area produced 265 mil tons of asphalt for road applications in 2014, while the amount of available Reclaimed Asphalt Pavement (RAP) was more than 50 mil tons. The use of RAP in new blended mixes reduces the need of neat bitumen, making RAP recycling economically attractive. This study investigates the potential use of styrene-bacrylate polymer and extracted Reclaimed Asphalt Pavement (RAP) in Hot Mix Asphalt (HMA) with different percentages b...

  6. IMPROVING OF RECLAIMED ASPHALT PAVEMENTS USING VINYL ACETATE-BUTYL ACRYLATE POLYMER

    OpenAIRE

    Nasser, A M; Abd El-Wahab

    2017-01-01

    According to the most recent surveys, the European area produced 265 mil tons of asphalt for road applications in 2014, while the amount of available Reclaimed Asphalt Pavement (RAP) was more than 50 mil tons. The use of RAP in new blended mixes reduces the need of neat bitumen, making RAP recycling economically attractive. This study investigates the potential use of vinyl acetate-bacrylate polymer and extracted Reclaimed Asphalt Pavement (RAP) in Hot Mix Asphalt (HMA) with different percent...

  7. Gold Electrodes Modified with Molecular Imprinted Acrylate Polymer for Impedimetric Determination of Testosterone

    OpenAIRE

    Amina Betatache; Florence Lagarde; Corinne SANGLAR; Anne BONHOMME; Didier LEONARD; Nicole JAFFREZIC-RENAULT

    2014-01-01

    A moleculary imprinted polymer (MIP) sensor was developed for impedimetric detection of testosterone. 4,4’-azobis(4-cyanovaleric acid) initiator was first grafted onto a gold electrode modified by a self-assembled monolayer of thiolamine (11-amino-1-undecanethiol). Methacrylic acid and ethylene glycol dimethacrylate were prepolymerized by photo-polymerization in presence of testosterone as template and then spincoated and polymerized on the functionalized electrode surface. The different step...

  8. Biointegration of corneal macroporous membranes based on poly(ethyl acrylate) copolymers in an experimental animal model.

    Science.gov (United States)

    Alió del Barrio, Jorge L; Chiesa, Massimo; Gallego Ferrer, Gloria; Garagorri, Nerea; Briz, Nerea; Fernandez-Delgado, Jorge; Sancho-Tello Valls, Maria; Botella, Carmen Carda; García-Tuñón, Ignacio; Bataille, Laurent; Rodriguez, Alejandra; Arnalich-Montiel, Francisco; Gómez Ribelles, Jose L; Antolinos-Turpín, Carmen M; Gómez-Tejedor, Jose A; Alió, Jorge L; De Miguel, Maria P

    2015-03-01

    Currently available keratoprosthesis models (nonbiological corneal substitutes) have a less than 75% graft survival rate at 2 years. We aimed at developing a model for keratoprosthesis based on the use of poly(ethyl acrylate) (PEA)-based copolymers, extracellular matrix-protein coating and colonization with adipose-derived mesenchymal stem cells. Human adipose tissue derived mesenchymal stem cells (h-ADASC) colonization efficiency of seven PEA-based copolymers in combination with four extracellular matrix coatings were evaluated in vitro. Then, macroporous membranes composed of the optimal PEA subtypes and coating proteins were implanted inside rabbit cornea. After a 3-month follow-up, the animals were euthanized, and the clinical and histological biointegration of the implanted material were assessed. h-ADASC adhered and survived when cultured in all PEA-based macroporous membranes. The addition of high hydrophilicity to PEA membranes decreased h-ADASC colonization in vitro. PEA-based copolymer containing 10% hydroxyethyl acrylate (PEA-HEA10) or 10% acrylic acid (PEA-AAc10) monomeric units showed the best cellular colonization rates. Collagen plus keratan sulfate-coated polymers demonstrated enhanced cellular colonization respect to fibronectin, collagen, or uncoated PEAs. In vivo implantation of membranes resulted in an extrusion rate of 72% for PEA, 50% for PEA-AAc10, but remarkably of 0% for PEA-HEA10. h-ADASC survival was demonstrated in all the membranes after 3 months follow-up. A slight reduction in the extrusion rate of h-ADASC colonized materials was observed. No significant differences between the groups with and without h-ADASC were detected respect to transparency or neovascularization. We propose PEA with low hydroxylation as a scaffold for the anchoring ring of future keratoprosthesis. © 2014 Wiley Periodicals, Inc.

  9. Urea free synthesis of chitin-based acrylate superabsorbent polymers under homogeneous conditions: Effects of the degree of deacetylation and the molecular weight.

    Science.gov (United States)

    Liu, T G; Wang, Y T; Li, B; Deng, H B; Huang, Z L; Qian, L W; Wang, X

    2017-10-15

    In order to understand the chemical structure of chitin-based acrylate superabsorbent polymers (SAP), chitin was dissolved in NaOH aqueous solution via freezing-thawing cyclic treatment without urea, subsequently, a transparent hydrogel was prepared by copolymerizing the alkali-chitin solution and acrylic acid directly. The effects of the degree of deacetylation (DDA) and the molecular weight (Mw) of chitin on the properties of SAP were investigated in detail. With increasing the DDA and Mw, the yield improved while the water absorbency decreased, yet the effect of DDA is insignificant if the Mw is smaller enough. The structures were characterized by FT-IR, XRD, TG, DSC, XPS, solid-state (13)C NMR and elemental analyses. The results indicated that the poly(acrylic acid) chains were successfully grafted onto the chitin backbones, and the reaction sites were the NH2 on the chitosan units. The possible mechanism was further discussed, which was similar to that suggested for chitosan-g-poly(acrylic acid) SAP. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Gold Electrodes Modified with Molecular Imprinted Acrylate Polymer for Impedimetric Determination of Testosterone

    Directory of Open Access Journals (Sweden)

    Amina Betatache

    2014-05-01

    Full Text Available A moleculary imprinted polymer (MIP sensor was developed for impedimetric detection of testosterone. 4,4’-azobis(4-cyanovaleric acid initiator was first grafted onto a gold electrode modified by a self-assembled monolayer of thiolamine (11-amino-1-undecanethiol. Methacrylic acid and ethylene glycol dimethacrylate were prepolymerized by photo-polymerization in presence of testosterone as template and then spincoated and polymerized on the functionalized electrode surface. The different steps of MIP sensor fabrication were controlled using electrochemical impedance spectroscopy (EIS, Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrometry. After template removal, the biosensor response, expressed as the variation of charge transfer resistance at the electrode/electrolyte interface measured by EIS, increased linearly with testosterone concentration up to 50 µg.L-1. The sensitivity was 0.28 per log C for testosterone, while it was only 0.0085 and 0.020 for methyltestosterone and 17b-estradiol, respectively. A very good limit of detection (103 ng.L-1 was achieved for testosterone. The sensitivity of the non imprinted polymer sensor, prepared the same way but in absence of template, was 18 times lower than that obtained with the MIP.

  11. Folic acid conjugated cross-linked acrylic polymer (FA-CLAP) hydrogel for site specific delivery of hydrophobic drugs to cancer cells.

    Science.gov (United States)

    Pillai, Jisha Jayadevan; Thulasidasan, Arun Kumar Theralikattu; Anto, Ruby John; Chithralekha, Devika Nandan; Narayanan, Ashwanikumar; Kumar, Gopalakrishnapillai Sankaramangalam Vinod

    2014-07-15

    The hydrogel based system is found to be rarely reported for the delivery of hydrophobic drug due to the incompatibility of hydrophilicity of the polymer network and the hydrophobicity of drug. This problem can be solved by preparing semi-interpenetrating network of cross-linked polymer for tuning the hydrophilicity so as to entrap the hydrophobic drugs. The current study is to develop a folic acid conjugated cross-linked pH sensitive, biocompatible polymeric hydrogel to achieve a site specific drug delivery. For that, we have synthesized a folic acid conjugated PEG cross-linked acrylic polymer (FA-CLAP) hydrogel and investigated its loading and release of curcumin. The formed polymer hydrogel was then conjugated with folic acid for the site specific delivery of curcumin to cancer cells and then further characterized and conducted the cell uptake and cytotoxicity studies on human cervical cancer cell lines (HeLa). In this study, we synthesized folic acid conjugated cross-linked acrylic hydrogel for the delivery of hydrophobic drugs to the cancer site. Poly (ethyleneglycol) (PEG) diacrylate cross-linked acrylic polymer (PAA) was prepared via inverse emulsion polymerization technique and later conjugated it with folic acid (FA-CLAP). Hydrophobic drug curcumin is entrapped into it and investigated the entrapment efficiency. Characterization of synthesized hydogel was done by using Fourier Transform-Infrared spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC). Polymerization and folate conjugation was confirmed by FT-IR spectroscopy. The release kinetics of drug from the entrapped form was studied which showed initial burst release followed by sustained release due to swelling and increased cross-linking. In vitro cytotoxicity and cell uptake studies were conducted in human cervical cancer (HeLa) cell lines. Results showed that curcumin entrapped folate conjugated cross-linked acrylic polymer (FA-CLAP) hydrogel showed

  12. Extended release promethazine HCl using acrylic polymers by freeze-drying and spray-drying techniques: formulation considerations

    Directory of Open Access Journals (Sweden)

    Ruchi Tiwari

    2009-12-01

    Full Text Available The present study investigated a novel extended release system of promethazine hydrochloride (PHC with acrylic polymers Eudragit RL100 and Eudragit S100 in different weight ratios (1:1 and 1: 5, and in combination (0.5+1.5, using freeze-drying and spray-drying techniques. Solid dispersions were characterized by Fourier-transformed infrared spectroscopy (FT-IR, differential scanning calorimetry (DSC, Powder X-ray diffractometry (PXRD, Nuclear magnetic resonance (NMR, Scanning electron microscopy (SEM, as well as solubility and in vitro dissolution studies in 0.1 N HCl (pH 1.2, double-distilled water and phosphate buffer (pH 7.4. Adsorption tests from drug solution to solid polymers were also performed. A selected solid dispersion system was developed into capsule dosage form and evaluated for in vitro dissolution studies. The progressive disappearance of drug peaks in thermotropic profiles of spray-dried dispersions were related to increasing amount of polymers, while SEM studies suggested homogenous dispersion of drug in polymer. Eudragit RL100 had a greater adsorptive capacity than Eudragit S100, and thus its combination in (0.5+1.5 for S100 and RL 100 exhibited a higher dissolution rate with 97.14% drug release for twelve hours. Among different formulations, capsules prepared by combination of acrylic polymers using spray-drying (1:0.5 + 1.5 displayed extended release of drug for twelve hours with 96.87% release followed by zero order kinetics (r²= 0.9986.O presente trabalho compreendeu estudo de um novo sistema de liberação prolongada de cloridrato de prometazina (PHC com polímeros acrílicos Eudragit RL100 e Eudragit S100 em diferentes proporções em massa (1:1 e 1:5 e em combinação (0,5+1,5, utilizando técnicas de liofilização e de secagem por aspersão As dispersões sólidas foram caracterizadas por espectrofotometria no infravermelho por transformada de Fourier (FT-IR, calorimetria diferencial de varredura (DSC, difratometria

  13. Scanning thermal lithography of tailored tert-butyl ester protected carboxylic acid functionalized (meth)acrylate polymer platforms.

    Science.gov (United States)

    Duvigneau, Joost; Schönherr, Holger; Vancso, G Julius

    2011-10-01

    In this paper, we report on the development of tailored polymer films for high-resolution atomic force microscopy based scanning thermal lithography (SThL). In particular, full control of surface chemical and topographical structuring was sought. Thin cross-linked films comprising poly(tert-butyl methacrylate) (MA(20)) or poly(tert-butyl acrylate) (A(20)) were prepared via UV initiated free radical polymerization. Thermogravimetric analysis (TGA) and FTIR spectroscopy showed that the heat-induced thermal decomposition of MA(20) by oxidative depolymerization is initially the primary reaction followed by tert-butyl ester thermolysis. By contrast, no significant depolymerization was observed for A(20). For A(20) and MA(20) (at higher temperatures and/or longer reaction times) the thermolysis of the tert-butyl ester liberates isobutylene and yields carboxylic acid groups, which react further intramolecularly to cyclic anhydrides. The values of the apparent activation energies (E(a)) for the thermolysis were calculated to be 125 ± 13 kJ mol(-1) and 116 ± 7 kJ mol(-1) for MA(20) and A(20), respectively. Both MA(20) and A(20) films showed improved thermomechanical stability during SThL compared to non cross-linked films. Carboxylic acid functionalized lines written by SThL in A(20) films had a typically ~10 times smaller width compared to those written in MA(20) films regardless of the tip radius of the heated probe and did not show any evidence for thermochemically or thermomechanically induced modification of film topography. These observations and the E(a) of 45 ± 3 kJ mol(-1) for groove formation in MA(20) estimated from the observed volume loss are attributed to oxidative thermal depolymerization during SThL of MA(20) films, which is considered to be the dominant reaction mechanism for MA(20). The smallest line width values obtained for MA(20) and A(20) films with SThL were 83 ± 7 nm and 21 ± 2 nm, whereas the depth of the lines was below 1 nm, respectively.

  14. Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries

    OpenAIRE

    Liangming Wei; Changxin Chen; Zhongyu Hou; Hao Wei

    2016-01-01

    The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dim...

  15. Graft copolymerization of acrylic acid to cassava starch-Evaluation of the influences of process parameters by an experimental design method

    NARCIS (Netherlands)

    Witono, J. R.; Noordergraaf, I. W.; Heeres, H. J.; Janssen, L. P. B. M.

    2012-01-01

    The graft copolymerization of cassava starch with acrylic acid was investigated using a free radical initiator system (Fe2+/H2O2 redox system) in water. A comprehensive understanding of the important variables and their interaction has been obtained by applying an experimental design method. In this

  16. Surface tension of polymer melts - experimental investigations of its effect on polymer-polymer adhesion

    DEFF Research Database (Denmark)

    Jankova Atanasova, Katja; Islam, Mohammad Aminul; Hansen, Hans Nørgaard

    The surface tension of polymer melts is important for the bond strength of two component polymer parts through their roles in the process of wetting, adsorption and adhesion. This investigation deals with the influence of the melt surface tension and substrate surface energy on the polymer......-polymer bond strength during two component polymer processing. Polymer materials PS, POM, ABS, PEl, PEEK and PC are chosen for the investigation. Pendant drop method showed that in case of PS and POM, the melt surface tension was decreased with increasing temperature. The substrate surface energies....... The results and discussion presented in this paper reflect the temperature dependent behaviours of the surface tension and surface energy of polymers and their effects on the polymer-polymer bond strength....

  17. Surface tension of polymer melts - experimental investigations of its effects on polymer-polymer adhesion

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Jankova Atanasova, Katja; Hansen, Hans Nørgaard

    The surface tension of polymer melts is important for the bond strength of two component polymer parts through their roles in the process of wetting, adsorption and adhesion. This investigation deals with the influence of the melt surface tension and substrate surface energy on the polymer......-polymer bond strength during two component polymer processing. Polymer materials PS, POM, ABS, PEI, PEEK and PC are chosen for the investigation. Pendant drop method showed that in case of PS and POM, the melt surface tension was decreased with increasing temperature. The substrate surface energies....... The results and discussion presented in this paper reflect the temperature dependent behaviours of the surface tension and surface energy of polymers and their effects on the polymer-polymer bond strength....

  18. Marginal discrepancy dimensions of single unit metal crowns fabricated by using CAD-CAM-milled acrylate resin polymer blocks or a conventional waxing technique.

    Science.gov (United States)

    Lalande, David; Hodd, Jeffrey A; Brousseau, John S; Ramos, Van; Dunham, Daniel; Rueggeberg, Frederick

    2017-10-14

    Because crowns with open margins are a well-known problem and can lead to complications, it is important to assess the accuracy of margins resulting from the use of a new technique. Currently, data regarding the marginal fit of computer-aided design and computer-aided manufacturing (CAD-CAM) technology to fabricate a complete gold crown (CGC) from a castable acrylate resin polymer block are lacking. The purpose of this in vitro study was to compare marginal discrepancy widths of CGCs fabricated by using either conventional hand waxing or acrylate resin polymer blocks generated by using CAD-CAM technology. A plastic model of a first mandibular molar was prepared by using a 1-mm, rounded chamfer margin on the entire circumference of the tooth. The master die was duplicated 30 times, and 15 wax patterns were fabricated by using a manual waxing technique, and 15 were fabricated by using CAD-CAM technology. All patterns were invested and cast, and resulting CGCs were cemented on their respective die by using resin-modified glass ionomer cement. The specimens were then embedded in acrylic resin and sectioned buccolingually. The buccal and lingual marginal discrepancies of each sectioned portion were measured by using microscopy at ×50 magnification. Data were subjected to repeated measures 2-way ANOVA, by using the Tukey post hoc pairwise comparison test (α=.05). The factor of "technique" had no significant influence on marginal discrepancy measurement (P=.431), but a significant effect of "margin location" (P=.019) was noted. The confounding combination of factors was found to be significantly lower marginal discrepancy dimensions of the lingual margin discrepancy than on the buccal side by using CAD-CAM technology. The marginal discrepancy of CAD-CAM acrylate resin crowns was not significantly different from those made with a conventional manual method; however, lingual margin discrepancies present from CAD-CAM-prepared crowns were significantly less than those

  19. 21 CFR 173.5 - Acrylate-acrylamide resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylate-acrylamide resins. 173.5 Section 173.5... CONSUMPTION Polymer Substances and Polymer Adjuvants for Food Treatment § 173.5 Acrylate-acrylamide resins. Acrylate-acrylamide resins may be safely used in food under the following prescribed conditions: (a) The...

  20. N-Heterocyclic Olefins as Initiators for the Polymerization of (Meth)Acrylic Monomers: A Combined Experimental and Theoretical Approach

    KAUST Repository

    Naumann, Stefan

    2017-08-25

    The zwitterionic organopolymerization of four different acrylic monomers (N,N-dimethylacrylamide, methyl acrylate, methyl methacrylate and tert-butyl methacrylate) based on neutral initiators, so-called N-heterocyclic olefins (NHOs), is presented. Scope and underlying (deactivation-)mechanisms where studied in a combined experimental and computational effort. From a range of differently structured NHOs it emerged that imidazole-, in contrast to imidazoline- and benzimidazole-derivatives, readily polymerize the selected monomers. While the additive-free reactions proceed with a relatively low degree of control to yield largely atactic material, for the acrylamide the addition of LiCl as µ-type ligand has been shown to result in a rapid and quantitative monomer consumption. The thus generated poly(N,N-dimethyl acrylamide) was found to be highly isotactic (>90% isotactic dyads) with high molecular weight (Mn = 250 000 – 650 000 g/mol, ÐM = 1.3- 1.6). Complementing DFT calculations considered the zwitterionic chain growth with respect to competing side reactions, namely spirocycles and enamine formation. It was found that NHOs with unsaturated backbone better support the zwitterionic chain growth, with the spirocycles acting as dormant species that slow down but do not quench the polymerization process. Contrasting this, enamine formation irreversibly terminates the polymerization and is found to be energetically favored. This pathway can be blocked by introduction of substituents on the exocyclic carbon of the NHO, resulting in structures like 2-isopropylidene-1,3,4,5-tetramethylimidazoline (4) which consequently deliver the most controlled polymerizations. Finally, a good correlation of the initiation energy barrier with the buried volume (%VBur) and the Parr electrophilicity index is described, allowing for a quick and reliable screening of potential monomers based on these two readily accessible parameters.

  1. Preparation, thermal properties and thermal reliabilities of microencapsulated n-octadecane with acrylic-based polymer shells for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xiaolin [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China); Song, Guolin; Chu, Xiaodong; Li, Xuezhu [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Tang, Guoyi, E-mail: tanggy@tsinghua.edu.cn [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China)

    2013-01-10

    Highlights: Black-Right-Pointing-Pointer n-Octadecane was encapsulated by p(butyl methacrylate) (PBMA) and p(butyl acrylate). Black-Right-Pointing-Pointer Microcapsules using divinylbenzene as crosslinking agent have better quality. Black-Right-Pointing-Pointer Microcapsule with butyl methacrylate-divinylbenzene has highest latent heat. Black-Right-Pointing-Pointer Microcapsule with butyl methacrylate-divinylbenzene has greatest thermal stability. Black-Right-Pointing-Pointer Phase change temperatures and enthalpies of the microcapsules varied little after thermal cycle. - Abstract: Microencapsulation of n-octadecane with crosslinked p(butyl methacrylate) (PBMA) and p(butyl acrylate) (PBA) as shells for thermal energy storage was carried out by a suspension-like polymerization. Divinylbenzene (DVB) and pentaerythritol triacrylate (PETA) were employed as crosslinking agents. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy (SEM). Thermal properties, thermal reliabilities and thermal stabilities of the as-prepared microPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The microPCMs prepared by using DVB exhibit greater heat capacities and higher thermal stabilities compared with those prepared by using PETA. The thermal resistant temperature of the microPCM with BMA-DVB polymer was up to 248 Degree-Sign C. The phase change temperatures and latent heats of all the as-prepared microcapsules varied little after 1000 thermal cycles.

  2. Graphene oxide/poly(acrylic acid)/gelatin nanocomposite hydrogel: experimental and numerical validation of hyperelastic model.

    Science.gov (United States)

    Faghihi, Shahab; Karimi, Alireza; Jamadi, Mahsa; Imani, Rana; Salarian, Reza

    2014-05-01

    Owing to excellent thermal and mechanical properties, graphene-based nanomaterials have recently attracted intensive attention for a wide range of applications, including biosensors, bioseparation, drug release vehicle, and tissue engineering. In this study, the effects of graphene oxide nanosheet (GONS) content on the linear (tensile strength and strain) and nonlinear (hyperelastic coefficients) mechanical properties of poly(acrylic acid) (PAA)/gelatin (Gel) hydrogels are evaluated. The GONS with different content (0.1, 0.3, and 0.5 wt.%) is added into the prepared PAA/Gel hydrogels and composite hydrogels are subjected to a series of tensile and stress relaxation tests. Hyperelastic strain energy density functions (SEDFs) are calibrated using uniaxial experimental data. The potential ability of different hyperelastic constitutive equations (Neo-Hookean, Yeoh, and Mooney-Rivlin) to define the nonlinear mechanical behavior of hydrogels is verified by finite element (FE) simulations. The results show that the tensile strength (71%) and elongation at break (26%) of composite hydrogels are significantly increased by the addition of GONS (0.3 wt.%). The experimental data is well fitted with those predicted by the FE models. The Yeoh material model accurately defines the nonlinear behavior of hydrogels which can be used for further biomechanical simulations of hydrogels. This finding might have implications not only for the improvement of the mechanical properties of composite hydrogels but also for the fabrication of polymeric substrate materials suitable for tissue engineering applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Prediction of drug solubility in an acrylate adhesive based on the drug-polymer interaction parameter and drug solubility in acetonitrile.

    Science.gov (United States)

    Li, Jianwei; Masso, Jeremy; Guertin, Jon

    2002-10-04

    This paper describes the correlation of drug solubility in isooctyl acrylate/acrylamide/vinyl acetate (IOA/ACM/VOAc, 75:5:20) adhesive with a relative drug-polymer interaction parameter. This parameter, defined previously as the amount of molecules (Ln) sorbed onto the adhesive when swollen by acetonitrile (ACN) [J. Controlled Release 82 (2002) 1], represents the differential interaction of drug with the adhesive relative to ACN. When the drug solubility in the adhesive (Ln) and ACN (Ln) are used to describe drug-polymer and drug-ACN interactions, the following linear relationship is expected: Ln=Ln(0)+pLn+qLn (p and q are coefficients). This model is evaluated by the drug solubility in the adhesive measured by differential scanning calorimetry (DSC), and drug solubility in ACN. It is concluded that there is an excellent linear relationship for the parameters involved. As a result, the model can be used to compute the solubility in the polymer for new drug candidates. Moreover, the amount of sorbed molecules and solubility in ACN can be either easily measured or computed based on their molecular properties.

  4. Improvement of transmission properties of visible pilot beam for polymer-coated silver hollow fibers with acrylic silicone resin as buffer layer for sturdy structure

    Science.gov (United States)

    Iwai, Katsumasa; Takaku, Hiroyuki; Miyagi, Mitsunobu; Shi, Yi-Wei; Zhu, Xiao-Song; Matsuura, Yuji

    2017-02-01

    Flexible hollow fibers with 530-μm-bore size were developed for infrared laser delivery. Sturdy hollow fibers were fabricated by liquid-phase coating techniques. A silica glass capillary is used as the substrate. Acrylic silicone resin is used as a buffer layer and the buffer layer is firstly coated on the inner surface of the capillary to protect the glass tube from chemical damages due to the following silver plating process. A silver layer was inner-plated by using the conventional silver mirror-plating technique. To improve adhesion of catalyst to the buffer layer, a surface conditioner has been introduced in the method of silver mirror-plating technique. We discuss improvement of transmission properties of sturdy polymer-coated silver hollow fibers for the Er:YAG laser and red pilot beam delivery.

  5. Theoretical and Experimental Studies of Polymer Adsorption and Polymer Mediated Interactions

    OpenAIRE

    Xie, Fei

    2016-01-01

    Polyelectrolyte adsorption and polymer mediated interactions in different colloidal polymer systems have been studied in this work. Theoretical methods and experimental techniques are combined, in order to obtain more general reliable results, as well as a deep understanding of the molecular mechanisms that are responsible for the observed behaviors. Two different types of highly charged cationic polyions have been used to explore the adsorption onto oppositely charged surfaces. The adsorptio...

  6. Experimental Study and Numerical Solution of Poly Acrylic Acid Supported Magnetite Nanoparticles Transport in a One-Dimensional Porous Media

    Directory of Open Access Journals (Sweden)

    M. Golzar

    2014-01-01

    Full Text Available Recently, iron nanoparticles have attracted more attention for groundwater remediation due to its potential to reduce subsurface contaminants such as PCBs, chlorinated solvents, and heavy metals. The magnetic properties of iron nanoparticles cause to attach to each other and form bigger colloid particles of iron nanoparticles with more rapid sedimentation rate in aqueous environment. Using the surfactants such as poly acrylic acid (PAA prevents iron nanoparticles from forming large flocs that may cause sedimentation and so increases transport distance of the nanoparticles. In this study, the transport of iron oxide nanoparticles (Fe3O4 stabilized with PAA in a one-dimensional porous media (column was investigated. The slurries with concentrations of 20,100 and 500 (mg/L were injected into the bottom of the column under hydraulic gradients of 0.125, 0.375, and 0.625. The results obtained from experiments were compared with the results obtained from numerical solution of advection-dispersion equation based on the classical colloid filtration theory (CFT. The experimental and simulated breakthrough curves showed that CFT is able to predict the transport and fate of iron oxide nanoparticles stabilized with PAA (up to concentration 500 ppm in a porous media.

  7. Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate)-poly(vinyl alcohol)/poly(acrylic acid) interpenetrating polymer networks for improving optrode-neural tissue interface in optogenetics.

    Science.gov (United States)

    Lu, Yi; Li, Yanling; Pan, Jianqing; Wei, Pengfei; Liu, Nan; Wu, Bifeng; Cheng, Jinbo; Lu, Caiyi; Wang, Liping

    2012-01-01

    The field of optogenetics has been successfully used to understand the mechanisms of neuropsychiatric diseases through the precise spatial and temporal control of specific groups of neurons in a neural circuitry. However, it remains a great challenge to integrate optogenetic modulation with electrophysiological and behavioral read out methods as a means to explore the causal, temporally precise, and behaviorally relevant interactions of neurons in the specific circuits of freely behaving animals. In this study, an eight-channel chronically implantable optrode array was fabricated and modified with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate)-poly(vinyl alcohol)/poly(acrylic acid) interpenetrating polymer networks (PEDOT/PSS-PVA/PAA IPNs) for improving the optrode-neural tissue interface. The conducting polymer-hydrogel IPN films exhibited a significantly higher capacitance and lower electrochemical impedance at 1 kHz as compared to unmodified optrode sites and showed significantly improved mechanical and electrochemical stability as compared to pure conducting polymer films. The cell attachment and neurite outgrowth of rat pheochromocytoma (PC12) cells on the IPN films were clearly observed through calcein-AM staining. Furthermore, the optrode arrays were chronically implanted into the hippocampus of SD rats after the lentiviral expression of synapsin-ChR2-EYFP, and light-evoked, frequency-dependant action potentials were obtained in freely moving animals. The electrical recording results suggested that the modified optrode arrays showed significantly reduced impedance and RMS noise and an improved SNR as compared to unmodified sites, which may have benefited from the improved electrochemical performance and biocompatibility of the deposited IPN films. All these characteristics are greatly desired in optogenetic applications, and the fabrication method of conducting polymer-hydrogel IPNs can be easily integrated with other modification methods to build a

  8. Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries

    Science.gov (United States)

    Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

    2016-01-01

    The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA. PMID:26786315

  9. Mitigation of biofilm formation on corrugated cardboard fresh produce packaging surfaces using a novel thiazolidinedione derivative integrated in acrylic emulsion polymers

    Directory of Open Access Journals (Sweden)

    Michael eBrandwein

    2016-02-01

    Full Text Available Various surfaces associated with the storage and packing of food are known to harbor distinct bacterial pathogens. Conspicuously absent among the plethora of studies implicating food packaging materials and machinery is the study of corrugated cardboard packaging, the worldwide medium for transporting fresh produce. In this study, we observed the microbial communities of three different store-bought fruits and vegetables, along with their analogue cardboard packaging using high throughput sequencing technology. We further developed an anti-biofilm polymer meant to coat corrugated cardboard surfaces and mediate bacterial biofilm growth on said surfaces. Integration of a novel thiazolidinedione derivative into the acrylic emulsion polymers was assessed using Energy Dispersive X-ray Spectrometry analysis and surface topography was visualized and quantified on corrugated cardboard surfaces. Biofilm growth was measured using q-PCR targeting the gene encoding 16s rRNA. Additionally, architectural structure of the biofilm was observed using SEM. The uniform integration of the thiazolidinedione derivative TZD-6 was confirmed, and it was determined via q-PCR to reduce biofilm growth by ~80% on tested surfaces. A novel and effective method for reducing microbial load and preventing contamination on food packaging is thereby proposed.

  10. MM and QM: conformational and vibrational spectra analysis of 2-hydroxyethyl acrylate.

    Science.gov (United States)

    Belaidi, O; Adjim, M; Bouchaour, T; Maschke, U

    2015-02-25

    2-Hydroxyethyl acrylate is generally used with other acrylic and methacrylic products in order to get the desired characteristics of the final product. In this work we are about to make an assignment of experimental infrared bands with the help of a theoretical quantum chemistry calculations. The exact knowledge of some bands which are not characteristics of acrylic materials will enable us to make a quick analysis with available techniques of low costs for mixtures of polymers based on acrylate and methacrylate molecules. In the experimental part, the infrared spectrum of 2-hydroxyethyl acrylate is obtained by using a FTIR Perkin Elmer model 2000. In the computational part and as first step, the theoretical calculations are performed by the semi-empirical AM1 method for excluding similar structures of 2-hydroxyethyl acrylate molecule by a meticulous conformational analysis. As a second step the obtained structures are optimized using DFT. The simulated frequencies are then scaled and a tentative assignment is made based on band intensities and PED percentages. The theoretical calculations predict the existence of thirteen conformations two of them represent the majority of experimental bands in the infrared spectrum. Two neighbor experimental bands located at 1301 and 1207 cm(-1) maybe used as characteristic bands to locate and distinguish the existence of one or both conformations. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Toward pH-responsive coating materials--high-throughput study of (meth)acrylic copolymers.

    Science.gov (United States)

    Krieg, Andreas; Arici, Elif; Windhab, Norbert; Schattka, Jan Hendrik; Schubert, Stephanie; Schubert, Ulrich S

    2014-08-11

    The release behavior of a model compound (β-naphthol orange) encapsulated in (meth)acrylate-based statistical copolymers under different environmental conditions was investigated. From monomers of varying polarity (methyl acrylate, ethyl acrylate, tert-butyl acrylate, 2-ethylhexyl methacrylate, and benzyl methacrylate) in combination with methacrylic acid, five polymer series were synthesized by free radical polymerization. The pH-dependent release kinetics were investigated via UV-vis spectroscopy at pH 1.2 and 6.8, simulating physiological conditions in the stomach and intestines. Furthermore, the influence of different ethanol contents (0 and 40 vol %) in the acidic medium was investigated. The whole approach was designed to meet the requirements of a high-throughput experimentation workflow.

  12. 78 FR 6213 - Styrene-2-Ethylhexyl Acrylate Copolymer; Tolerance Exemption

    Science.gov (United States)

    2013-01-30

    ... AGENCY 40 CFR Part 180 Styrene-2-Ethylhexyl Acrylate Copolymer; Tolerance Exemption AGENCY: Environmental...; also known as styrene-2-ethylhexyl acrylate copolymer when used as an inert ingredient in a pesticide...-risk polymers are described in 40 CFR 723.250(d). Styrene-2-ethylhexyl acrylate copolymer conforms to...

  13. Physically cross-linked polymer binder based on poly(acrylic acid) and ion-conducting poly(ethylene glycol-co-benzimidazole) for silicon anodes

    Science.gov (United States)

    Lim, Sanghyun; Lee, Kukjoo; Shin, Inseop; Tron, Artur; Mun, Junyoung; Yim, Taeeun; Kim, Tae-Hyun

    2017-08-01

    The practical applications of Si electrodes in lithium-ion batteries are limited since they undergo large changes in volume during charge and discharge, and consequently become highly deteriorated. A novel binder system holding silicon particles together and preventing disintegration of the electrode during operation hence needs to be developed to enable reliable cycleability. In the current work, such a new polymer binder system, based on poly(acrylic acid) (PAA) and poly(ethylene glycol-co-benzimidazole) (PEGPBI), is developed for silicon anodes. The physical crosslinking using acid-base interactions between PAA and PBI, together with the ion-conducting PEG group, yields physical properties for the resulting PAA-PEGPBI-based anodes that are better than those of electrodes based on the currently available PAA binder, and yields good cell performances. A Si-based electrode with high loading levels of 1.0-1.3 mg cm-2 (0.7-0.91 Si mg cm-2) is reliably manufactured using specifically PAA-PEGPBI-2, which is made with 2 wt% of PEGPBI relative to PAA, and shows a very high capacity value of 1221 mAh g-1 at a rate of 0.5 C after 50 cycles, and a high capacity value of more than 1600 mAh g-1 at a high rate of 2 C.

  14. Diels-Alder Trapping of Photochemically Generated Dienes with Acrylic Esters: A Novel Approach to Photocured Polymer Film Development

    Science.gov (United States)

    Ilhan, Faysal; Tyson, Daniel S.; Smith, Deedee; Meador, Mary Ann; Meador, Michael A.

    2004-01-01

    Diels-Alder cycloadditions have often been utilized in polymer synthesis as an alternative to condensation reactions. In our earlier efforts, we developed a new method for the preparation of linear aromatic polyimides, which employs o-quionodimethanes (o-QDMs), generated by a well-known photochemical reaction: the photoenolization of o-methylphenyl ketones. Photolysis of o-methylbenzophenone 1 produces hydroxy-o-quino- diemthane 2, which can be trapped with dienophiles, such as dimethyl acetylenedicarboxylate, to efficiently yield the corresponding cycloadduct (Scheme 1). Here we extend this approach to a novel photocuring process for development of polymer films. We synthesized a series of molecules with multi o-mehtylphenyl ketone functionalities. We further investigated these molecules as photoreactive monomers to obtain polyester films through Diels-Alder cycloadditions.

  15. In situ preparation of powder and the sorption behaviors of molecularly imprinted polymers through the complexation between polymer ion of methyl methacrylate/acrylic acid and Ca++ ion.

    Science.gov (United States)

    Chough, Sung Hyo; Park, Kwang Ho; Cho, Seung Jin; Park, Hye Ryoung

    2014-09-02

    Molecularly imprinted polymer (MIP) powders were prepared using a simple complexation strategy between the polymer carboxylate groups and template molecule followed by metal cation cross-linking of residual polymer carboxylates. Polymer powders were formed in situ by templating carboxylic acid containing polymers with 4-ethylaniline (4-EA), followed by addition of an aqueous CaCl2 solution. The solution remained homogeneous. The powders were prepared by precipitation by slowly adding a non-solvent, H2O, to the mixture. The resulting particles were very porous with uptake capacity that approached the theoretical value. We suggest two types of complexes are formed between the template, 4-EA, and polymer. The isolated entry type forms well defined cavities for the template with high specific selectivity, while the adjacent entry type forms wider binding sites without specific sorption for isomeric molecules. To evaluate conditions for forming materials with high affinity and selectivity, three MIPs were prepared containing 0.5, 1.0, and 1.5 equivalents of template to the base polymer. The MIP containing 0.5 eq showed higher specific selectivity to 4-EA, but the MIP containing 1.5 eq had noticeably lower selectivity. The lower selectivity is attributed to poorly formed binding sites with little selective sorption to any isomer when the higher ratio of template was used. However at the lower ratio of template the isolated entry is preferably formed to produce well defined binding cavities with higher selectivity to template. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Poly(meth)acrylate-based coatings.

    Science.gov (United States)

    Nollenberger, Kathrin; Albers, Jessica

    2013-12-05

    Poly(meth)acrylate coatings for pharmaceutical applications were introduced in 1955 with the launch of EUDRAGIT(®) L and EUDRAGIT(®) S, two types of anionic polymers. Since then, by introducing various monomers into their polymer chains and thus altering their properties, diverse forms with specific characteristics have become available. Today, poly(meth)acrylates function in different parts of the gastrointestinal tract and/or release the drug in a time-controlled manner. This article reviews the properties of various poly(meth)acrylates and discusses formulation issues as well as application possibilities. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

    OpenAIRE

    Helmut Ritter; Monir Tabatabai; Markus Herrmann

    2016-01-01

    We describe the synthesis of bromo-tert-butyloxycarbonyl (Br-t-BOC)-amino-protected monomers 2-((1-bromo-2-methylpropan-2-yl)oxycarbonylamino)ethyl (meth)acrylate 3a,b. For this purpose, 2-isocyanatoethyl (meth)acrylate 1a,b was reacted with 1-bromo-2-methylpropan-2-ol (2a). The free radical polymerization of (Br-t-BOC)-aminoethyl (meth)acrylates 3a,b yielded poly((Br-t-BOC)-aminoethyl (meth)acrylate) 6a,b bearing protected amino side groups. The subsequent solvolysis of the Br-t-BOC function...

  18. Nanoclays reinforced glass ionomer cements: dispersion and interaction of polymer grade (PG) montmorillonite with poly(acrylic acid).

    Science.gov (United States)

    Fareed, Muhammad A; Stamboulis, Artemis

    2014-01-01

    Montmorillonite nanoclays (PGV and PGN) were dispersed in poly(acrylic acid) (PAA) for utilization as reinforcing filler in glass ionomer cements (GICs). Chemical and physical interaction of PAA and nanoclay (PGV and PGN) was studied. PAA–PGV and PAA–PGN solutions were prepared in different weight percent loadings of PGV and PGN nanoclay (0.5-8.0 wt%) via exfoliation-adsorption method. Characterization was carried out by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fourier transform infrared (FTIR) spectroscopy. XRD results of PAA–PGN demonstrated that the interlayer space expanded from 12.83 to 16.03 Å indicating intercalation whereas the absence of the peak at d(001) in PAA–PGV indicated exfoliation. XPS scans of PGV and PGN nanoclays depicted the main peak of O 1s photoelectron due to Si–O–M (M = Mg, Al, Fe) whereas, Si–O–Al linkages were identified by Si 2p or Si 2s and Al 2p or Al 2s peaks. The disappearance of the Na peak confirmed that PAA molecules exchanged sodium ions present on surface of silicate layers and significantly reduced the electrostatic van-der-Waals forces between silicate plates resulting in intercalation or exfoliation. FTIR spectra of PAA–nanoclay suspensions demonstrated the presence of a new peak at 1,019 cm(-1) associated with Si–O– stretching vibrations which increased with increasing nanoclays concentration. Information concerning the dispersion of nanoclay in PAA aqueous solutions, chemical reaction and increase interlayer space in montmorillonite nanoclay is particularly useful regarding dispersion and reinforcement of nanoclay in PAA.

  19. Preparation and characterization of silane-modified SiO2particles reinforced resin composites with fluorinated acrylate polymer.

    Science.gov (United States)

    Liu, Xue; Wang, Zengyao; Zhao, Chengji; Bu, Wenhuan; Na, Hui

    2018-01-10

    A series of fluorinated dental resin composites were prepared with two kinds of SiO 2 particles. Bis-GMA (bisphenol A-glycerolate dimethacrylate)/4-TF-PQEA (fluorinated acrylate monomer)/TEGDMA (triethylene glycol dimethacrylate) (40/30/30, wt/wt/wt) was introduced as resin matrix. SiO 2 nanopartices (30nm) and SiO 2 microparticles (0.3µm) were silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) and used as fillers. After mixing the resin matrix with 0%, 10%, 20%, 30% SiO 2 nanopartices and 0%, 10%, 20%, 30%, 40%, 50% SiO 2 microparticles, respectively, the fluorinated resin composites were obtained. Properties including double bond conversion (DC), polymerization shrinkage (PS), water sorption (W p ), water solubility (W y ), mechanical properties and cytotoxicity were investigated in comparison with those of neat resin system. The results showed that, filler particles could improve the overall performance of resin composites, particularly in improving mechanical properties and reducing PS of composites along with the addition of filler loading. Compared to resin composites containing SiO 2 microparticles, SiO 2 nanoparticles resin composites had higher DC, higher mechanical properties, lower PS and lower W p under the same filler content. Especially, 50% SiO 2 microparticles reinforced resins exhibited the best flexural strength (104.04 ± 7.40MPa), flexural modulus (5.62 ± 0.16GPa), vickers microhardness (37.34 ± 1.13 HV), compressive strength (301.54 ± 5.66MPa) and the lowest polymerization (3.42 ± 0.22%). Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Impact of the nature of the compliant electrodes on the dielectric constant of acrylic and silicone electroactive polymers

    Science.gov (United States)

    Vu-Cong, T.; Jean-Mistral, C.; Sylvestre, A.

    2012-10-01

    Dielectric elastomers are emerging electroactive materials used in high performance applications such as robots, artificial muscles and energy harvesting. The development of such applications requires the use of accurate, predictive, reliable models which take into account the dielectric constant (permittivity) of these materials. This dielectric constant is not clearly defined for such applications and depends on many parameters. This leads to values dispersed in the literature for the same electroactive polymer. This paper shows that the nature of the compliant electrodes can influence this dielectric constant significantly. However, the reduction generally observed in this permittivity according to the stretching of elastomer cannot be imputed to the nature of these electrodes, and rather confirms an effect of the volume of the elastomer. This tends to prove that the influence of the compliant electrode is located at the electrode-elastomer interfaces. In addition, the nature of the metallic particles embedded in the electrode grease seems not to influence the value of the dielectric constant. Lastly, we propose analytic laws to describe changes of the dielectric constant as a function of the temperature and the deformation of the material. This makes it possible to define new limits of operation for these polymers for actuators and energy harvesting applications.

  1. Pyrolysis of carbonaceous particles and properties of Carbonaceous-g-Poly (acrylic acid-co-acrylamide superabsorbent polymer for agricultural applications

    Directory of Open Access Journals (Sweden)

    Ghazali S.

    2016-01-01

    Full Text Available Utilisation of fertilizer and water are very important in determining the production of agriculture nowadays. The excessive use of fertilizer in plantation somehow could leads to environmental pollution. The present study reported a synthesis of controlled release water retention (CRWR fertilizer coating with superabsorbent polymer (SAPs. Superabsorbent polymer (SAPs are polymers that have ability to absorb and retain large amounts of water relative to their own mass. The presence of coating layer of SAPs on fertilizer granules was believed could reduce excessive used of fertilizer by controlling their dissolution rates and also reduce the environmental pollution. In this study, the effect on the addition of carbonaceous filler in SAPs on the water absorbency was also be compared with control SAPs (without carbonaceous particles. In this study, the carbonaceous filler were obtained from pyrolysis process of empty fruit bunch (EFB biomass. The synthesized of SAPs and carbonaceous-SAPs were carried out via solution polymerization technique by using monomer of poly(acrylic acid (AA, acrylamide (AM, cross linker, methylene bisacrylamide (MBA and initiator, ammonium peroxodisulfate (APS that partially neutralized with sodium hydroxide (NaOH. The CRWR fertilizer was later be prepared by coated the fertilizer granule with SAPs and carbonaceous-SAPs. The water absorbency, morphology and the bonding formation of both CRWR fertilizer were investigated by using tea-beg method, Scanning Electron Microscopy (SEM and Fourier Transform Infrared Spectrophotometer (FTIR, respectively. Moreover, the water retention studies was conducted in order to investigate the efficiency of CRWR coated with SAP and carbonaceous-SAP in retaining the water content in different soil (organic and top soil. Based on the results, the CRWR fertilizer that was coated with carbonaceous-SAP had higher water absorbency value than the CRWR fertilizer without carbonaceous-SAP. Meanwhile

  2. STAR POLYMER/WATER SOLUTIONS: NEW EXPERIMENTAL FINDINGS

    Directory of Open Access Journals (Sweden)

    C.Branca

    2002-01-01

    Full Text Available The purpose of the present work is to highlight a number of recent experimental results that have contributed significantly to the research area of star polymer. Firstly we will refer to a very impressive SANS work by J.Peyrelasse, C.Perreur, J.-P.Habas and J.Francois which is focused on the study of the structural properties of aqueous solutions of a star copolymer of PEO and PPO by Small Angle Neutron Scattering. Next, we will refer to some experimental advances reported in the work by R.Triolo, V.Arrighi, A.Triolo, P.Migliardo, S.Magazu, J.B.McClain, D.Betts, J.M.DeSimone, H.D.Middendorf, which deals with a study of some dynamical properties of PS-b-PFOA aggregates in supercritical CO2 by Quasi Elastic Neutron Scattering.

  3. A Lithium/Polysulfide Battery with Dual-Working Mode Enabled by Liquid Fuel and Acrylate-Based Gel Polymer Electrolyte.

    Science.gov (United States)

    Liu, Ming; Ren, Yuxun; Zhou, Dong; Jiang, Haoran; Kang, Feiyu; Zhao, Tianshou

    2017-01-25

    The low density associated with low sulfur areal loading in the solid-state sulfur cathode of current Li-S batteries is an issue hindering the development of this type of battery. Polysulfide catholyte as a recyclable liquid fuel was proven to enhance both the energy density and power density of the battery. However, a critical barrier with this lithium (Li)/polysulfide battery is that the shuttle effect, which is the crossover of polysulfides and side deposition on the Li anode, becomes much more severe than that in conventional Li-S batteries with a solid-state sulfur cathode. In this work, we successfully applied an acrylate-based gel polymer electrolyte (GPE) to the Li/polysulfide system. The GPE layer can effectively block the detrimental diffusion of polysulfides and protect the Li metal from the side passivation reaction. Cathode-static batteries utilizing 2 M catholyte (areal sulfur loading of 6.4 mg cm-2) present superior cycling stability (727.4 mAh g-1 after 500 cycles at 0.2 C) and high rate capability (814 mAh g-1 at 2 C) and power density (∼10 mW cm-2), which also possess replaceable and encapsulated merits for mobile devices. In the cathode-flow mode, the Li/polysulfide system with catholyte supplied from an external tank demonstrates further improved power density (∼69 mW cm-2) and stable cycling performance. This novel and simple Li/polysulfide system represents a significant advancement of high energy density sulfur-based batteries for future power sources.

  4. The electrospinning of the copolymer of styrene and butyl acrylate for its application as oil absorbent.

    Science.gov (United States)

    Xu, Naiku; Cao, Jipeng; Lu, Yuyao

    2016-01-01

    Electrospun polystyrene materials have been employed as oil absorbents, but they have visible drawbacks such as poor strength at low temperature and unreliable integrity because of brittleness and insufficient cohesive force among fibers. Butyl acrylate can polymerize into flexible chains, and its polymer can be used as elastomer and adhesive material. Thereby it is possible to obtain the material that has better performance in comparison with electrospun polystyrene material through the electrospinning of the copolymer of styrene and butyl acrylate. In this work, a polymer was synthesized through suspension polymerization by using styrene and butyl acrylate as comonomers. The synthesis of the copolymer of styrene and butyl acrylate was verified through dissolution and hydrolysis experimental data; as well through nuclear magnetic resonance spectrometry. The viscous flow activation energy of the solution consisting of copolymer and N, N-dimethylformamide was determined via viscosity method and then adopted to establish the entanglement characteristics of butyl acrylate's chain segments. Finally, in order to electrospin the copolymer solution into fibrous membrane, the effects of monomer feed ratio and spinning parameters were investigated. The prepared fibrous membrane was found to have a potential use as oil absorbent.

  5. Experimental dosimetry of Ho-166 bioglass seed polymer-protected

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Luciana B.; Campos, Tarcisio P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2011-07-01

    This study aims to develop experimental dosimetry of Ho-166 bio glass seed for brachytherapy studies using GAFCHROMIC EBT2 radio chromium films. The methodology consists of placement of radio chromium films in a compressed breast phantom, along with bio glass polymer-protected seeds of [Si: Ca: Ho] and [Si: Ca: Ho: Zr]. The bio glass seeds were encapsulated with polyvinyl alcohol, before being activated and used in the study. The bio glass seeds were introduced into the breast phantom, along with radio chromium films for a period of 2 hours. After the exposure time, radio chromium films were removed from phantom and digitized for analysis in ImageDIG 2.0 program, which quantifies the intensity of RGB (Red, Green, Blue). The dose calculation was evaluated by Monte Carlo technique. Experimental and theoretical data were used to calibrate the dose distribution. The results were plotted on graphs and dose iso curves were obtained. As conclusion it is possible to perform dosimetry in Ho-166 seed brachytherapy using radio chromium films, limited to a short exposure time and small activity. (author)

  6. Experimental measurement and correlation of phase behavior for the CO{sub 2}+heptafluorobutyl acrylate and CO{sub 2}+heptafluorobutyl methacrylate systems at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Soon-Do; Byun, Hun-Soo [Chonnam National University, Yeosu (Korea, Republic of)

    2014-03-15

    Experimental data of high pressure phase behavior from 313.2 to 393.2 K and pressures up to about 14.3 MPa were reported for binary mixture of 2,2,3,3,4,4,4-heptafluorobutyl acrylate (HFBA) and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFBMA) in supercritical carbon dioxide. The high pressure experiment was performed by static method using variable-volume view cell apparatus. The CO{sub 2}+HFBA and CO{sub 2}+HFBMA systems are correlated with the Peng-Robinson equation of state using a van der Waals one-fluid mixing rule. The CO{sub 2}+HFBA and CO{sub 2}+HFBMA systems exhibit type-I phase behavior with continuous critical mixture curves.

  7. Lower critical solution temperature behavior of alpha-substituted poly(acrylic acids)s, cyclopolymerization of N-vinylformamido-methylacrylates, and use of the World-Wide Web in polymer science education

    Science.gov (United States)

    Michalovic, Mark Stephen

    A series of alpha-substituted poly(acrylic acid)s was synthesized and characterized. Their aqueous solution properties were investigated with respect to lower critical solution temperature (LCST) behavior. Poly(alpha-methoxymethylacrylic acid) was found to have a lower critical solution temperature (LCST) of 46°C, poly(alpha-methoxyethoxymethylacrylic acid) showed an LCST of 26.5°C and poly(alpha-methoxyethoxyethoxymethylacrylic acid) showed an LCST of 66°C. The cloud points of the solutions of these polymers were found to be sensitive to pH, and to concentrations of additives such as urea, salts, and surfactants. Because of low molecular weight due to chain transfer, high molecular weight analogs of the ether-linked polymers were synthesized in which ester linkages joined the oligo-oxyethylene segment to the acrylate moiety. Poly(alpha-methoxyethoxyacetoxymethylacrylic acid) was the only one of this series to give an LCST with a value of 52.5°C. Copolymers of t-butyl alpha-methoxymethylacrylate (tBMMA) with alpha-(1H,1H- perfluorooctyloxymethyl)acrylic acid (PFOMA) were synthesized, deprotected and their lower critical solution temperatures (LCSTs) evaluated. At PFOMA feed ratios of 0.25 mol % or less, no observable change in the LCST was observed, while at PFOMA feed ratios of above 0.25 mol % to 1.125 mol %, a large linear decrease in the LCST was observed with increasing fluorocarbon content. t-Butyl alpha-(N-vinylformamidomethyl)acrylate (tBVFA) and ethyl alpha-(N-vinylformamidomethyl)acrylate (EVFA) were synthesized from t-butyl alpha-bromomethylacrylate and ethyl alpha-chloromethylacrylate, respectively. tBVFA was found to cyclopolymerize at 120°C in DMF, DMSO, and 1,2-dichlorobenzene at solvent:monomer ratios of 10:1 vol:wt. Molecular weights for poly(tBVFA) ranged from 10,000 to 13,000 as estimated by size-exclusion chromatography. At lower solvent monomer ratio (1:1), and at lower temperature (71°C), crosslinking occurred. EVFA was found to

  8. Biodegradable polymers by reactive blending trans-esterification of thermoplastic starch with poly (vinyl acetate) and poly (vinyl acetate-co-butyl acrylate)

    CSIR Research Space (South Africa)

    Vargha, V

    2005-04-01

    Full Text Available Wheat starch was reacted with poly (vinyl acetate) and with poly (vinyl acetate-co-butyl acrylate) in an internal mixer at 150 _C in the absence of catalyst, and in the presence of sodium carbonate, zinc-acetate and titanium (IV) but oxide...

  9. Experimental Assessment of the Use of a Novel Superabsorbent polymer (SAP for the Optimization ofWater Consumption in Agricultural Irrigation Process

    Directory of Open Access Journals (Sweden)

    Giuseppe Cannazza

    2014-07-01

    Full Text Available In this work, an innovative cellulose-based superabsorbent polymer (SAP was experimentally assessed as an environmentally friendly alternative to acrylate-based SAPs, for the optimization of water consumption in agriculture. The cellulose-based SAP was synthesized and tested for its swelling capability in different aqueous media. The effectiveness of the SAP in agricultural applications was then evaluated by analyzing its performance after several absorption/desorption cycles, over a period of approximately 80 days, upon addition to different types of soil, i.e., white and red soil, for the cultivation of two varieties of plants typical of the Mediterranean area (tomatoes and chicory. The results confirmed that SAP-amended soil can store a considerable amount of water and can release it gradually to the plant roots when needed. The adoption of the proposed SAP in cultivations could thus represent a promising solution for the rationalization of water resources, especially in desert areas.

  10. A new experimental procedure for incorporation of model contaminants in polymer hosts

    NARCIS (Netherlands)

    Papaspyrides, C.D.; Voultzatis, Y.; Pavlidou, S.; Tsenoglou, C.; Dole, P.; Feigenbaum, A.; Paseiro, P.; Pastorelli, S.; Cruz Garcia, C. de la; Hankemeier, T.; Aucejo, S.

    2005-01-01

    A new experimental procedure for incorporation of model contaminants in polymers was developed as part of a general scheme for testing the efficiency of functional barriers in food packaging. The aim was to progressively pollute polymers in a controlled fashion up to a high level in the range of

  11. Experimental investigations into the physics of light emitting conjugated polymers

    CERN Document Server

    Whitelegg, S A

    2001-01-01

    chloroprecursor MEH-PPV in-situ of ITO results in a reaction of the polymer with ITO, which significantly shift the emission to high energies. Electroabsorption spectroscopy is used to probe the internal electric fields within operating polymer light emitting devices. When a PPV based LED in an oxygen/water atmosphere, degradation of the device occurs whereby an electric field develops, which opposes the applied electric field. This opposing electric field subsequently decays when the device is turned to its off state. Operating lifetimes and emission efficiencies of polymer light emitting devices are now approaching values suitable for the manufacture and sale of polymer light emitting based products. However, degradation and device performance still continues to be of chief concern and in order for these to be improved the underlying physical processes have to be identified. This thesis aims to identify some of these processes. An investigation in to the optical absorption and emission properties of insolub...

  12. Thermal bulk polymerization of cholesteryl acrylate

    NARCIS (Netherlands)

    de Visser, A.C.; de Groot, K.; Feijen, Jan; Bantjes, A.

    1971-01-01

    The thermal bulk polymerization of cholesteryl acrylate was carried out in the solid phase, the mesomorphic phase, and the liquid phase to study the effect of monomer ordering on polymerization rate and polymer properties. The rate increased with decreasing ordering (or enhanced mobility) of the

  13. Thermal Polymerization of N-Butyl Acrylate

    Science.gov (United States)

    Ingham, J. D.

    1982-01-01

    Simple new polymerization method enables production of n-butyl acrylate polymer of desired high molecular weight, without disadvantages that usually attend more conventional methods. Process, which is hybrid of thermal, solution, and emulsion polymerization methods, involves controlled thermal polymerization of monomer at moderate temperatures without use of catalysts or additives.

  14. Development and Evaluation of Ketoprofen Acrylic Transdermal ...

    African Journals Online (AJOL)

    Purpose: To fabricate ketoprofen transdermal patches (KTPs) using an acrylic pressure-sensitive adhesive (PSA) polymer. Methods: KTPs were prepared using solvent casting method. The influence of the amount of PSA, drug content, and terpenes as penetration enhancers on the characteristics of the patch, namely, ...

  15. Preparation of polymer-modified electrodes: A literature and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Jayanta, Pat Siripastr [Stony Brook Univ., NY (United States); Ishida, Takanobu [Stony Brook Univ., NY (United States)

    1991-05-01

    A literature review is presented on the field of polymer modified electrodes which can be electrochemically generated. It is suggested that a possible application of these polymer modified electrodes is as a regeneratable catalysis packing material for use in couter-current exchange columns. Secondly, there is a presentation of experimental results dealing with possible electrode modification using difluoro- and dimethyl- phenols and fluorinated derivatives of styrene, benzoquinone and hydroquinone. It appears that dimethylphenol shows the most potential of the monomers experimentally tested in providing a stable polymer modified electrode surface.

  16. Preparation of polymer-modified electrodes: A literature and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Jayanta, P.S.; Ishida, Takanobu.

    1991-05-01

    A literature review is presented on the field of polymer modified electrodes which can be electrochemically generated. It is suggested that a possible application of these polymer modified electrodes is as a regeneratable catalysis packing material for use in couter-current exchange columns. Secondly, there is a presentation of experimental results dealing with possible electrode modification using difluoro- and dimethyl- phenols and fluorinated derivatives of styrene, benzoquinone and hydroquinone. It appears that dimethylphenol shows the most potential of the monomers experimentally tested in providing a stable polymer modified electrode surface. 170 refs., 31 figs., 1 tab.

  17. Waterborne hyperbranched alkyd-acrylic resin obtained by miniemulsion polymerization

    Directory of Open Access Journals (Sweden)

    Edwin Murillo

    Full Text Available Abstract Four waterborne hyperbranched alkyd-acrylic resins (HBRAA were synthesized by miniemulsion polymerization from a hyperbranched alkyd resin (HBR, methyl methacrylate (MMA, butyl acrylate (BA and acrylic acid (AA, by using benzoyl peroxide (BPO and ammonium persulfate (AP as initiators. The reaction between HBR and acrylic monomers was evidenced by differential scanning calorimetric (DSC, nuclear magnetic resonance (NMR and gel permeation chromatography (GPC. The conversion percentage, glass transition temperature (Tg, content of acrylic polymer (determined by soxhlet extraction and molecular weight increased with the content of acrylic monomers used in the synthesis. The main structure formed during the synthesis was the HBRAA. The analysis by dynamic light scattering (DLS showed that the particle size distribution of HBRAA2, HBRAA3 and HBRAA4 resins were mainly monomodal. The film properties (gloss, flexibility, adhesion and drying time of the HBRAA were good.

  18. Pyrolysis of carbonaceous particles and properties of Carbonaceous-g-Poly (acrylic acid-co-acrylamide) superabsorbent polymer for agricultural applications

    OpenAIRE

    Ghazali S.; Jamari S.; Noordin N.; Tan K. M.

    2016-01-01

    Utilisation of fertilizer and water are very important in determining the production of agriculture nowadays. The excessive use of fertilizer in plantation somehow could leads to environmental pollution. The present study reported a synthesis of controlled release water retention (CRWR) fertilizer coating with superabsorbent polymer (SAPs). Superabsorbent polymer (SAPs) are polymers that have ability to absorb and retain large amounts of water relative to their own mass. The presence of coati...

  19. The Effect of Water Acrylate Dispersion on the Properties of Polymer-Carbon Nanotube Composites / Wpływ Wodnej Dyspersji Akrylanowej Na Właściwości Kompozytów Polimer-Nanorurki Węglowe

    Directory of Open Access Journals (Sweden)

    Zygoń P.

    2015-12-01

    Full Text Available The paper presents properties of polymer composites reinforced with carbon nanotubes (CNT containing various mixtures of dispersion. Acrylates of different particle size and viscosity were used to produce composites. The mechanical strength of composites was determined by three-point bending tests. The roughness parameter of composites was determined with a profilometer and compared with the roughness parameter determined via atomic force microscopy (AFM. Also X-ray studies (phase composition analysis, crystallite sizes determination were carried out on these composites. Measurements of the surface topography using the Tapping Mode method were performed, acquiring the data on the height and on the phase imaging. The change of intensity, crystallite size and half-value width of main reflections originating from carbon within the composites have been determined using the X-ray analysis. The density of each obtained composite was determined as well as the resistivity at room temperature. The density of composites is quite satisfactory and ranges from 0.27 to 0.35 g/cm3. Different composites vary not only in strength but also in density. Different properties were achieved by the use of various dispersions. Carbon nanotubes constituting the reinforcement for a polymer composite improve the mechanical properties and conductivity composite.

  20. In situ generation of silver nanoparticles in poly(vinyl alcohol)/poly(acrylic acid) polymer membranes in the absence of reducing agent and their effect on pervaporation of a water/acetic acid mixture

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhard, Shvshankar; Kwon, Yong Sung; Moon, MyungJun; Shon, Min Young [Dept. of Industrial Chemistry, Pukyong National University, Busan (Korea, Republic of); Park, You In; Nam, Seung Eun [Center for membranes, Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of)

    2016-12-15

    The in situ generation of silver nanoparticles in a poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) polymer matrix in the absence of any additional reducing agent is reported and tends to the membrane fabrication using solution-casting. Its effect on the separation of a water/acetic acid mixture by pervaporation is described. The results of UV spectroscopy, scanning electron microscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses showed that the silver nanoparticles were successfully prepared and well dispersed in the polymer matrix. The increased hydrophilicity of the PVA/PAA membrane due to the presence of silver nanoparticles was confirmed by Fourier transform infrared spectroscopy, contact angle measurements, and membrane absorption studies. Pervaporation data for composite membranes showed a three-fold increase in the flux value, while the initially decreased separation factor subsequently showed a constant value. Overall, the pervaporation data suggested that the presence of silver nanoparticles benefited the dehydration process.

  1. An Experimental-Theoretical Analysis of Protein Adsorption on Peptidomimetic Polymer Brushes

    OpenAIRE

    Lau, K. H. Aaron; Ren, Chunlai; Park, Sung Hyun; Szleifer, Igal; Messersmith, Phillip B.

    2011-01-01

    Surface-grafted water soluble polymer brushes are being intensely investigated for preventing protein adsorption to improve biomedical device function, prevent marine fouling, and enable applications in biosensing and tissue engineering. In this contribution, we present an experimental-theoretical analysis of a peptidomimetic polymer brush system with regard to the critical brush density required for preventing protein adsorption at varying chain lengths. A mussel adhesive-inspired DOPA-Lys p...

  2. Preparation and application of the sol-gel-derived acrylate/silicone co-polymer coatings for headspace solid-phase microextraction of 2-chloroethyl ethyl sulfide in soil.

    Science.gov (United States)

    Liu, Mingming; Zeng, Zhaorui; Fang, Huaifang

    2005-05-27

    Three types of novel acrylate/silicone co-polymer coatings, including co-poly(methyl acrylate/hydroxy-terminated silicone oil) (MA/OH-TSO), co-poly(methyl methacrylate/OH-TSO) (MMA/OH-TSO) and co-poly(butyl methacrylate/OH-TSO) (BMA/OH-TSO), were prepared for the first time by sol-gel method and cross-linking technology and subsequently applied to headspace solid-phase microextraction (HS-SPME) of 2-chloroethyl ethyl sulfide (CEES), a surrogate of mustard, in soil. The underlying mechanisms of the coating process were discussed and confirmed by IR spectra. The selectivity of the three types of sol-gel-derived acrylate/silicone coated fibers was studied, and the BMA/OH-TSO coated fibers exhibited the highest extraction ability to CEES. The concentration of BMA and OH-TSO in sol solution was optimized, and the BMA/OH-TSO (3:1)-coated fibers possessed the highest extraction efficiency. Compared with commercially available polyacrylate (PA) fiber, the sol-gel-derived BMA/OH-TSO (3:1) fibers showed much higher extraction efficiency to CEES. Therefore, the BMA/OH-TSO (3:1)-coated fibers were chosen for the analysis of CEES in soil matrix. The reproducibility of coating preparation was satisfactory, with the RSD 2.39% within batch and 3.52% between batches, respectively. The coatings proved to be quite stable at high temperature (to 350 degrees C) and in different solvents (organic or inorganic), thus their lifetimes (to 150 times) are longer than conventional fibers. Extraction parameters, such as the volume of water added to the soil, extraction temperature and time, and the ionic strength were optimized. The linearity was from 0.1 to 10 microg/g, the limit of detection (LOD) was 2.7 ng/g, and the RSD was 2.19%. The recovery of CEES was 88.06% in agriculture soil, 92.61% in red clay, and 101.95% in sandy soil, respectively.

  3. Poly(lauryl acrylate) and poly(stearyl acrylate) grafted multiwalled carbon nanotubes for polypropylene composites

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Jankova Atanasova, Katja; Hvilsted, Søren

    2014-01-01

    Two new polymer grafts on an industrial grade multiwalled carbon nanotube (MWCNT) were prepared through a non-oxidative pathway employing controlled free radical polymerization for surface initiated polymer grafting. After photochemical introduction of an ATRP initiator onto the MWCNT, polymeriza......Two new polymer grafts on an industrial grade multiwalled carbon nanotube (MWCNT) were prepared through a non-oxidative pathway employing controlled free radical polymerization for surface initiated polymer grafting. After photochemical introduction of an ATRP initiator onto the MWCNT...... to be substantially improved, where poly(lauryl acrylate) was found to be the superior surface modification, resulting in a conductive composite....

  4. Disinfection of denture base acrylic resin.

    Science.gov (United States)

    Lin, J J; Cameron, S M; Runyan, D A; Craft, D W

    1999-02-01

    During repair or adjustments of acrylic resin removable complete and partial dentures, particles of the acrylic resin from the interior of the prosthesis may expose dental personnel to microbial health hazards if the prosthesis has not been thoroughly disinfected. This study investigates the efficacy of a commercially prepared microbial disinfectant (Alcide) on the external and internal surfaces of acrylic resins. Four groups of acrylic resin were incubated in an experimental model to simulate the oral environment over time. Specimens were treated in 2 groups, disinfected and not disinfected, and then further grouped by breaking and not breaking. Analysis was performed with microbial colony counts, SEM, and statistical analyses. Viable microorganisms still remain on the internal and external surfaces of treated resins. Chlorine dioxide reduces, but does not eliminate, viable microorganisms on these dental prostheses.

  5. Influence of Polymer Molecular Weight on Drug-Polymer Solubility: A Comparison between Experimentally Determined Solubility in PVP and Prediction Derived from Solubility in Monomer.

    Science.gov (United States)

    Knopp, Matthias Manne; Olesen, Niels Erik; Holm, Per; Langguth, Peter; Holm, René; Rades, Thomas

    2015-09-01

    In this study, the influence of polymer molecular weight on drug-polymer solubility was investigated using binary systems containing indomethacin (IMC) and polyvinylpyrrolidone (PVP) of different molecular weights. The experimental solubility in PVP, measured using a differential scanning calorimetry annealing method, was compared with the solubility calculated from the solubility of the drug in the liquid analogue N-vinylpyrrolidone (NVP). The experimental solubility of IMC in the low-molecular-weight PVP K12 was not significantly different from that in the higher molecular weight PVPs (K25, K30, and K90). The calculated solubilities derived from the solubility in NVP (0.31-0.32 g/g) were found to be lower than those experimentally determined in PVP (0.38-0.40 g/g). Nevertheless, the similarity between the values indicates that the analogue solubility can provide valuable indications on the solubility in the polymer. Hence, if a drug is soluble in an analogue of the polymer, it is most likely also soluble in the polymer. In conclusion, the solubility of a given drug-polymer system is determined by the strength of the drug-polymer interactions rather than the molecular weight of the polymer. Therefore, during the first screenings for drug solubility in polymers, only one representative molecular weight per polymer is needed. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  6. Theoretical and Experimental Study of Plasmonic Polymer Solar Cells

    DEFF Research Database (Denmark)

    Mirsafaei, Mina; Adam, Jost; Madsen, Morten

    The organic bulk hetero-junction solar cell has remarkable advantages such as low cost, mechanical flexibility and simple process techniques. Recently, low-band gap photoactive materials have obtained a significant attention due to their potential to absorb a wider range of the solar spectrum...... to attain higher power conversion efficiencies. Many low-band gap photoactive materials, however, still show a relatively low external quantum efficiency of less than 60% [1]. One possible approach to improve the device performance is to increase the light absorption in the active layer. This may, amongst...... other approaches, be achieved by using nano- or micro-structures that trap light at specific wavelengths [2], or by using the localized surface plasmon resonance effect of metal nanoparticles in the devices. In this work, we theoretically studied planar polymer solar cell based on finite-difference time...

  7. Acrylates in contact dermatitis.

    Science.gov (United States)

    Sasseville, Denis

    2012-01-01

    Acrylates are plastic materials that are formed by the polymerization of monomers derived from acrylic or methacrylic acid. They have found numerous applications in paints, varnishes and adhesives, in the printing industry, in the medical and dental professions, and in artificial nails. Beginning in the 1950s, many reports of occupational and nonoccupational allergic contact dermatitis to (meth)acrylate monomers have been published. These molecules are strong irritants, and patch testing can induce active sensitization. When patch tested, acrylate-allergic patients often display multiple positive tests. These reactions may represent cross-reactions, or concomitant reactions due to the presence, in the products responsible for sensitization, of impurities not disclosed in material safety data sheets. (Meth)acrylates are volatile and unstable chemicals, as demonstrated by their rapid disappearance from commercially available patch test allergens when exposed to air for more than a few hours.

  8. Occupational fingertip eczema from acrylates in a manicurist

    Directory of Open Access Journals (Sweden)

    Denitza Zheleva

    2015-04-01

    Full Text Available Occupational hand eczema due to acrylates present in the workplace is a disease frequently reported among dentists, printers, and fiberglass workers. Acrylate monomers are used in the production of a great variety of polymers, including nail cosmetics. Our case report demonstrates a rare clinical presentations of allergic contact dermatitis from acrylic nails. Our patient was working as a manicurist and the diagnostic analyses revealed sensitation to some of the (meth acrylate compounds of her new nail cosmetics. Sculptured artificial acrylic and UV-hardened nails s are widely used in developed countries and they are gaining more and more popularity. We expect an increase in the number of cases of contact allergic dermatitis among manicurists and customers.

  9. Relations structure-propriétés et résistance à l’endommagement de vernis acrylate photo-polymérisables pour substrats thermoplastiques : évaluation de monomères bio-sourcés et de nano-charges

    OpenAIRE

    Prandato, Emeline

    2013-01-01

    The aim of this work was to develop 100% solids photo-polymerizable acrylate coatings, intended to protect thermoplastic pieces made of polycarbonate against mechanical damage, in particular scratches. The relationships between the composition, the structure and the properties of these coatings were examined. For this purpose the morphology, the thermomechanical properties and the scratch resistance of the materials, assessed by micro-scratch tests, were studied. The kinetics of the polymer n...

  10. Experimental Evaluation of a Total Heat Recovery Unit with Polymer Membrane Foils

    DEFF Research Database (Denmark)

    Fang, Lei; Yuan, Shu; Nie, Jinzhe

    2014-01-01

    A laboratory experimental study was conducted to investigate the energy performance of a total heat recovery unit using a polymer membranes heat exchanger. The study was conducted in twin climate chambers. One of the chambers simulated outdoor climate conditions and the other simulated the climat...

  11. Methods for the synthesis of deuterated acrylate salts

    Science.gov (United States)

    Yang, Jun; Bonnesen, Peter V.; Hong, Kunlun

    2014-09-09

    A method for synthesizing a deuterated acrylate of the Formula (1), the method comprising: (i) deuterating a propiolate compound of Formula (2) to a methyne-deuterated propiolate compound of Formula (3) in the presence of a base and D.sub.2O: and (ii) reductively deuterating the methyne-deuterated propiolate compound of Formula (3) in a reaction solvent in the presence of deuterium gas and a palladium-containing catalyst to afford the deuterated acrylate of the Formula (1). The resulting deuterated acrylate compounds, derivatives thereof, and polymers derived therefrom are also described.

  12. Investigation of Acrylic Acid at High Pressure using Neutron Diffraction

    DEFF Research Database (Denmark)

    Johnston, Blair F.; Marshall, William G.; Parsons, Simon

    2014-01-01

    This article details the exploration of perdeuterated acrylic acid at high pressure using neutron diffraction. The structural changes that occur in acrylic acid-d4 are followed via diffraction and rationalised using the Pixel method. Acrylic acid undergoes a reconstructive phase transition to a new...... phase at ~0.8 GPa and remains molecular to 7.2 GPa before polymerising on decompression to ambient pressure. The resulting product is analysed via Raman, FT-IR spectroscopy and Differential Scanning Calorimetry and found to possess a different molecular structure compared with polymers produced via...

  13. An experimental-theoretical analysis of protein adsorption on peptidomimetic polymer brushes.

    Science.gov (United States)

    Lau, K H Aaron; Ren, Chunlai; Park, Sung Hyun; Szleifer, Igal; Messersmith, Phillip B

    2012-01-31

    Surface-grafted water-soluble polymer brushes are being intensely investigated for preventing protein adsorption to improve biomedical device function, prevent marine fouling, and enable applications in biosensing and tissue engineering. In this contribution, we present an experimental-theoretical analysis of a peptidomimetic polymer brush system with regard to the critical brush density required for preventing protein adsorption at varying chain lengths. A mussel adhesive-inspired DOPA-Lys (DOPA = 3,4-dihydroxy-phenylalanine; Lys = lysine) pentapeptide surface grafting motif enabled aqueous deposition of our peptidomimetic polypeptoid brushes over a wide range of chain densities. Critical densities of 0.88 nm(-2) for a relatively short polypeptoid 10-mer to 0.42 nm(-2) for a 50-mer were identified from measurements of protein adsorption. The experiments were also compared with the protein adsorption isotherms predicted by a molecular theory. Excellent agreements in terms of both the polymer brush structure and the critical chain density were obtained. Furthermore, atomic force microscopy (AFM) imaging is shown to be useful in verifying the critical brush density for preventing protein adsorption. The present coanalysis of experimental and theoretical results demonstrates the significance of characterizing the critical brush density in evaluating the performance of an antifouling polymer brush system. The high fidelity of the agreement between the experiments and molecular theory also indicate that the theoretical approach presented can aid in the practical design of antifouling polymer brush systems. © 2011 American Chemical Society

  14. Experimental Investigation of Mechanical Properties of PVC Polymer under Different Heating and Cooling Conditions

    Directory of Open Access Journals (Sweden)

    Sarkawt Rostam

    2016-01-01

    Full Text Available Due to a widely increasing usage of polymers in various industrial applications, there should be a continuous need in doing research investigations for better understanding of their properties. These applications require the usage of the polymer in different working environments subjecting the material to various temperature ranges. In this paper, an experimental investigation of mechanical properties of polyvinyl chloride (PVC polymer under heating and cooling conditions is presented. For this purpose standard samples are prepared and tested in laboratory using universal material testing apparatus. The samples are tested under different conditions including the room temperature environment, cooling in a refrigerator, and heating at different heating temperatures. It is observed that the strength of the tested samples decreases with the increasing of heating temperature and accordingly the material becomes softer. Meanwhile the cooling environments give a clear increasing to the strength of the material.

  15. Development and characterization of a stable adhesive bond between a poly(dimethylsiloxane) catheter material and a bacterial biofilm resistant acrylate polymer coating.

    Science.gov (United States)

    Tyler, Bonnie J; Hook, Andrew; Pelster, Andreas; Williams, Paul; Alexander, Morgan; Arlinghaus, Heinrich F

    2017-05-23

    Catheter associated urinary tract infections are the most common health related infections worldwide, contributing significantly to patient morbidity and mortality and increased health care costs. To reduce the incidence of these infections, new materials that resist bacterial biofilm formation are needed. A composite catheter material, consisting of bulk poly(dimethylsiloxane) (PDMS) coated with a novel bacterial biofilm resistant polyacrylate [ethylene glycol dicyclopentenyl ether acrylate (EGDPEA)-co-di(ethyleneglycol) methyl ether methacrylate (DEGMA)], has been proposed. The coated material shows excellent bacterial resistance when compared to commercial catheter materials, but delamination of the EGDPEA-co-DEGMA coatings under mechanical stress presents a challenge. In this work, the use of oxygen plasma treatment to improve the wettability and reactivity of the PDMS catheter material and improve adhesion with the EGDPEA-co-DEGMA coating has been investigated. Argon cluster three dimensional-imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used to probe the buried adhesive interface between the EGDPEA-co-DEGMA coating and the treated PDMS. ToF-SIMS analysis was performed in both dry and frozen-hydrated states, and the results were compared to mechanical tests. From the ToF-SIMS data, the authors have been able to observe the presence of PDMS, silicates, salt particles, cracks, and water at the adhesive interface. In the dry catheters, low molecular weight PDMS oligomers at the interface were associated with poor adhesion. When hydrated, the hydrophilic silicates attracted water to the interface and led to easy delamination of the coating. The best adhesion results, under hydrated conditions, were obtained using a combination of 5 min O 2 plasma treatment and silane primers. Cryo-ToF-SIMS analysis of the hydrated catheter material showed that the bond between the primed PDMS catheter and the EGDPEA-co-DEGMA coating was stable in the

  16. Self-initiation of UV photopolymerization reactions using tetrahalogenated bisphenol A (meth)acrylates.

    Science.gov (United States)

    Pelras, Théophile; Knolle, Wolfgang; Naumov, Sergej; Heymann, Katja; Daikos, Olesya; Scherzer, Tom

    2017-05-17

    The potential of tetrachlorinated and tetrabrominated bisphenol A diacrylates and dimethacrylates for self-initiation of a radical photopolymerization was investigated. The kinetics of the photopolymerization of an acrylic model varnish containing halogenated monomers was studied by real-time FTIR spectroscopy, whereas the formation of reactive species and secondary products was elucidated by laser flash photolysis and product analysis by GC-MS after steady-state photolysis. The interpretation of the experimental data and the analysis of possible reaction pathways were assisted by quantum chemical calculations. It was shown that all halogenated monomers lead to a significant acceleration of the photopolymerization kinetics at a minimum concentration of 5 wt%. Steady-state and laser flash photolysis measurements as well as quantum chemical calculations showed that brominated and chlorinated samples do not follow the same pathway to generate radical species. Whereas chlorinated (meth)acrylates may cleave only at the C-O bonds of the carboxyl groups resulting in acrolein and oxyl radicals for initiation, brominated monomers may cleave either at the C-O bonds or at the C-Br bonds delivering aryl and bromine radicals. The quantum yields for the photolysis of the halogenated monomers were found to be in the order of 0.1 for acrylates and 0.2 for methacrylates (with an estimated error of 25%), independently of the attached Br and Cl halogens. Finally, the trihalogenated bisphenol A di(meth)acrylate radicals and the acrolein radicals were found to show the highest efficiencies for the reaction with another acrylic double bond leading to the formation of a polymer network.

  17. Determining heat loss from the surface of polymer films via modeling of experimental fluorescence thermometry

    Science.gov (United States)

    Firestone, Gabriel; Bochinski, Jason; Meth, Jeffrey; Clarke, Laura

    Understanding of the heat transfer characteristics of a polymer during processing is critical to predicting and controlling the resulting properties and has been studied extensively in injection molding. As new methodologies for polymer processing are developed, such as photothermal heating, it is important to build an understanding of how heat transfer properties change under these novel conditions. By combining theoretical and experimental approaches, the thermal properties of photothermally heated polymer films were measured. The key idea is that by measuring the steady state temperature profile of a spot heated polymer film via a fluorescence probe (the temperature versus distance from the heated region) and fitting to a theoretical model, heat transfer coefficients can be extracted. We apply this approach to three different polymer systems, crosslinked epoxy, poly(methyl methacrylate) and poly(ethylene oxide) thin films with a range of thicknesses, under different heating laser intensities and with different resultant temperatures. We will discuss the resultant trends and extension of the model beyond a simple spot heating configuration. Support from National Science Foundation CMMI-1069108 and CMMI-1462966.

  18. Theoretical and experimental study of dissolution of inhomogeneities formed during spinodal decomposition in polymer mixtures

    Science.gov (United States)

    Akcasu, A. Ziya; Bahar, I.; Erman, B.; Feng, Y.; Han, C. C.

    1992-10-01

    Dissolution (mixing or melting) of inhomogeneities formed during spinodal decomposition in binary polymer mixtures is studied both experimentally and theoretically. The details of the dissolution experiment with time-resolved light scattering on polystyrene/poly(vinylmethylether) are presented. The theoretical approach differs from that of Langer, Bar-on, and Miller in the way the fluctuations are treated in the nonlinear theory, and in the details of the calculations arising from the chain connectivity (polymer effect). The effect of mode coupling arising from nonlinearity on the relaxation rate is discussed. It is found both experimentally and theoretically that the wave number corresponding to peak intensity decreases in time asymptotically following a t-0.5 power law.

  19. Hydrophilic surface modification of acrylate-based biomaterials.

    Science.gov (United States)

    Arnal-Pastor, M; Comín-Cebrián, S; Martínez-Ramos, C; Monleón Pradas, M; Vallés-Lluch, A

    2016-04-01

    Acrylic polymers have proved to be excellent with regard to cell adhesion, colonization and survival, in vitro and in vivo. Highly ordered and regular pore structures thereof can be produced with the help of polyamide templates, which are removed with nitric acid. This treatment converts a fraction of the ethyl acrylate side groups into acrylic acid, turning poly(ethyl acrylate) scaffolds into a more hydrophilic and pH-sensitive substrate, while its good biological performance remains intact. To quantify the extent of such a modification, and be able to characterize the degree of hydrophilicity of poly(ethyl acrylate), poly(ethyl acrylate) was treated with acid for different times (four, nine and 17 days), and compared with poly(acrylic acid) and a 90/10%wt. EA/AAc copolymer (P(EA-co-AAc)). The biological performance was also assessed for samples immersed in acid up to four days and the copolymer, and it was found that the incorporation of acidic units on the material surface was not prejudicial for cells. This surface modification of 3D porous hydrophobic scaffolds makes easier the wetting with culture medium and aqueous solutions in general, and thus represents an advantage in the manageability of the scaffolds. © The Author(s) 2016.

  20. Dynamical mechanical analysis of photocrosslinked hyperbranched urethane acrylates

    Directory of Open Access Journals (Sweden)

    BRANKO DUNJIC

    2004-06-01

    Full Text Available A series of acrylate functionalized samples based on hyperbranched hydroxy-terminated polyesters with different molecular weights and different degrees of acrylation were synthesized. The obtained urethane acrylates were slightly yellow viscose liquids. Their composition was characterized by FTIR and 1H-NMR spectroscopy and their molecular weights were measured by GPC. All the synthesized samples were diluted with 25 wt.% 1,4-butanediol dimethacrylate (BDDM. The rheological properties of the uncured samples and the dynamic mechanical properties of the UV cured samples were examined. All the samples exhibit Newtonian behavior, which indicates the absence of physical entanglements in these polymers. The viscosity increases with increasing number of acrylic groups per molecule. The glass transition temperature of the UV cured samples increases with increasing the number of acrylic groups per molecule. The value of the storage modulus in the rubber-elastic plateau and the cross-link density increase with increasing number of acrylic groups per molecule. The formed networks are inhomogeneous and the residual unsaturation is the highest in the samples with the largest number of acrylic groups per molecule.

  1. Quantum theory and experimental studies of absorption spectra and photoisomerization of azobenzene polymers

    DEFF Research Database (Denmark)

    Pedersen, Thomas Garm; Ramanujam, P.S.; Johansen, P.M.

    1998-01-01

    The microscopic properties of azobenzene chromophores are important for a correct description of optical storage systems based on photoinduced anisotropy in azobenzene polymers. A quantum model of these properties is presented and verified by comparison to experimental absorption spectra for trans...... and cis isomers of cyano methoxy azobenzene. In addition, the trans --> cis quantum efficiency is measured, and hence the combined experimental and theoretical work allows one to determine the essential molecular properties, including magnitude and anisotropy of the absorption cross section and various...

  2. Industrially relevant epoxy-acrylate hybrid resin photopolymerizations

    Science.gov (United States)

    Ajiboye, Gbenga I.

    Photopolymerization of epoxy-acrylate hybrid resins takes advantages of inherent properties present in the free-radical and cationic reactions to reduce oxygen inhibition problems that plague free-radical reactions. Similarly, the combined reaction mechanisms reduce moisture sensitivity of the cationic reactions. Despite the advantages of epoxy-acrylate hybrid resins, problems persist that need to be addressed. For example, low conversion and polymerization rate of the epoxides are a problem, because the fast acrylate conversion prevents the epoxide from reaching high conversion. Controlling phase separation is challenging, since two moieties with different properties are reacting. The physical properties of the polymer will be impacted by the availability of different moieties. High shrinkage stress results from the acrylate moiety, causing buckling and cracking in film and coating applications. The overall goal of this study is to use the fundamental knowledge of epoxy-acrylate hybrid resins to formulate industrially viable polymers. In order to achieve this goal, the study focuses on the following objectives: (I) determine the apparent activation energy of the hybrid monomer METHB, (II) increase epoxide conversion and polymerization rate of hybrid formulations, and (III) control physical properties in epoxy-acrylate hybrid resins. In order to increase the epoxide conversion and rate of polymerization, the sensitivity of epoxides to alcohol is used to facilitate the activated monomer (AM) mechanism and induce a covalent bond between the epoxide and acrylate polymers through the hydroxyl group. It is hypothesized that if the AM mechanism is facilitated, epoxide conversion will increase. As a result, the resins can be tailored to control phase separation and physical properties, and shrinkage stress can be reduced. In pursuit of these objectives, the hybrid monomer METHB was polymerized at temperatures ranging from 30°C to 70°C to obtain apparent activation

  3. Efficacy of Natural Polymer Derivatives on Soil Physical Properties and Erosion on an Experimental Loess Hillslope.

    Science.gov (United States)

    Liu, Jun'e; Wang, Zhanli; Li, Yuanyuan

    2017-12-22

    Raindrops disperse large soil aggregates into smaller particles, which can clog soil pores, cause soil crusting, reduce rainfall infiltration and increase soil loss. It was found that natural polymer derivatives were effective in improving soil physical properties and decreasing soil erosion on an experimental loess hillslope. This study investigated the effect of new natural polymer derivatives (Jag S and Jag C162) on soil properties, rainfall infiltration and sediment yield at four rates of sprayed polymers (0, 1, 3 and 5 g/m²), three rainfall intensities (1, 1.5 and 2 mm/min) and a slope gradient of 15° with a silt loam soil through simulated rain. The results showed that both Jag S and Jag C162 significantly increased the shear strength and improved the aggregates composition of the soil surface. The water-stable soil aggregates >0.25 mm increased from 9% to 50% with increasing rates of Jag S and Jag C162. Jag S and Jag C162 also effectively increased rainfall infiltration and final infiltration rate, and reduced erosion compared to controls without natural polymer derivatives added. However, higher rates of Jag S produced lower infiltration rates. Although both Jag S and Jag C162 effectively influenced soil physical properties and erosion, the effect of Jag C162 was more significant than that of Jag S.

  4. Analysis of Mechanical and Thermogravimetric Properties of Composite Materials Based on PVA/MWCNT and Styrene-Acrylic Copolymer/MWCNT

    Science.gov (United States)

    Volynets, N. I.; Poddubskaya, O. G.; Demidenko, M. I.; Lyubimov, A. G.; Kuzhir, P. P.; Suslyaev, V. I.; Pletnev, M. A.; Zicans, Janis

    2017-08-01

    Mechanical and thermogravimetric properties of polymer composite materials with various concentrations of multiwalled carbon nanotubes effectively shielding radiation in the radio frequency (20 Hz - 1 MHz) and microwave (26-36 GHz) frequency ranges are studied. As a matrix, widely available polymeric materials, such as polyvinyl acetate and styrene-acrylate, were used in the form of dispersions. From the analysis of the obtained experimental data, it was shown that the introduction of carbon nanotubes into the polymer matrix makes it possible to increase mechanical properties and thermal stability of composite materials.

  5. Experimental and numerical investigations on the use of polymer Hopkinson pressure bars.

    Science.gov (United States)

    Harrigan, John J; Ahonsi, Bright; Palamidi, Elisavet; Reid, Steve R

    2014-08-28

    Split Hopkinson pressure bar (SHPB) testing has traditionally been carried out using metal bars. For testing low stiffness materials such as rubbers or low strength materials such as low density cellular solids considered primarily herein, there are many advantages to replacing the metal bars with polymer bars. An investigation of a number of aspects associated with the accuracy of SHPB testing of these materials is reported. Test data are used to provide qualitative comparisons of accuracy using different bar materials and wave-separation techniques. Sample results from SHPB tests are provided for balsa, Rohacell foam and hydroxyl-terminated polybutadiene. The techniques used are verified by finite-element (FE) analysis. Experimentally, the material properties of the bars are determined from impact tests in the form of a complex elastic modulus without curve fitting to a rheological model. For the simulations, a rheological model is used to define the bar properties by curve fitting to the experimentally derived properties. Wave propagation in a polymer bar owing to axial impact of a steel bearing ball is simulated. The results indicate that the strain histories can be used to determine accurately the viscoelastic properties of polymer bars. An FE model of the full viscoelastic SHPB set-up is then used to simulate tests on hyperelastic materials. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  6. Organic Polymers Modified with Inorganic Polyhedra

    National Research Council Canada - National Science Library

    Haddad, Timothy

    2002-01-01

    ...) macromers into organic polymers. These hybrid inorganic/organic thermoplastics based on styrenes, acrylics, imides, norbornenes or siloxanes, are reinforced by covalently linking monodisperse inorganic POSS clusters to the polymer backbone...

  7. Acrylic mechanical bond tests

    Energy Technology Data Exchange (ETDEWEB)

    Wouters, J.M.; Doe, P.J.

    1991-02-01

    The tensile strength of bonded acrylic is tested as a function of bond joint thickness. 0.125 in. thick bond joints were found to posses the maximum strength while the acceptable range of joints varied from 0.063 in. to almost 0.25 in. Such joints are used in the Sudbury Neutrino Observatory.

  8. Hyperbranched urethane-acrylates

    Directory of Open Access Journals (Sweden)

    Tasić Srba

    2004-01-01

    Full Text Available The synthesis, characterization and UV-curing of hyperbranched urethaneacrylates (HB-UA were investigated in this study. They were evaluated as oli-gomers in model UV curable coatings. HB-UAs were synthesized by reaction of an aliphatic hyperbranched polyester of the second generation (HBRG2 and an isocyanate adduct, obtained by the reaction of isophoronediisocyana-te and different hydroxy alkyl acrylates. Their thermal properties and viscosities depend on the degree of modification of HBRG2 and the type of hydroxy alkyl acrylate used. The introduction of a flexible alkoxylated spacer between the HBP core and acrylate end groups reduces steric hindrance by moving the cross linkable acrylate groups away from the HBP core and increase its reactivity. Due to the presence of abstractable H-atoms in the α-position to the ether links, HB-UAs based on poly(ethylene oxide monoacrylate are very reactive and do not show oxygen inhibition. The obtained coatings combine a high cross linking density with flexible segments between the cross links, which results in a good compromise between hardness and flexibility and have the potential to be used in different UV-curing applications.

  9. Experimental study on mass transfer of contaminants through an enthalpy recovery unit with polymer membrane foils

    DEFF Research Database (Denmark)

    Nie, Jinzhe; Fang, Lei

    2014-01-01

    recovery unit with polymer membrane foils was used as refeering unit in this study. The experiments were conducted with different outdoor thermal climates e.g. warm-humid and cold-dry climates; isothermal and non isothermal as well as equal humidity and non equal humidity with indoor climate. Three......Laboratory experimental studies were conducted to investigate the mass transfer of contaminants through a total heat recovery unit with polymer membranes foils. The studies were conducted in twin climate chambers which simulated outdoor and indoor thermal climates. One manufacturd total heat...... could transfer from exhaust air to supply air through the enthalpy recovery unit. The mass transfer efficiency of contaminants was independent of the hygro-thermal differences between indoor and outdoor climate conditions. The mass transfer ratio of the chemical contaminants in the total heat recovery...

  10. Experimental and theoretical aspects of studying themodynamics and mass transport in polymer-solvent systems

    Science.gov (United States)

    Davis, Peter Kennedy

    Mass transport and thermodynamics in polymer-solvent systems are two key areas of importance to the polymer industry. Numerous processes including polymerization reactors, membrane separations, foam production, devolatilization processes, film and coating drying, supercritical extractions, drug delivery, and even nano-technology require fundamental phase equilibria and diffusion information. Although such information is vital in equipment design and optimization, acquisition and modeling of these data are still in the research and development stages. This thesis is rather diverse as it addresses many realms of this broad research area. From high pressure to low pressure, experimental to theoretical, and infinite dilution to finite concentration, the thesis covers a wide range of topics that are of current importance to the industrial and academic polymer community. Chapter 1 discusses advances in the development of a new volumetric sorption pressure decay technique to make phase equilibrium and diffusion measurements in severe temperature-pressure environments. Chapter 2 provides the derivations and results of a new completely predictive Group Contribution Lattice Fluid Equation of State for multi-component polymer-solvent systems. The remaining four chapters demonstrate advances in the modeling of inverse gas chromatography (IGC) experiments. IGC has been used extensively of the last 50 years to make low pressure sorption and diffusion measurements at infinitely dilute and finite solvent concentrations. Chapter 3 proposes a new IGC experiment capable of obtaining ternary vapor-liquid equilibria in polymer-solvent-solvent systems. Also in that chapter, an extensive derivation is provided for a continuum model capable of describing the results of such an experiment. Chapter 4 presents new data collected on a packed column IGC experiment and a new model that can be used with those experimental data to obtain diffusion and partition coefficients. Chapter 5 addresses a

  11. Nanopigmented Acrylic Resin Cured Indistinctively by Water Bath or Microwave Energy for Dentures

    Directory of Open Access Journals (Sweden)

    L. S. Acosta-Torres

    2014-01-01

    Full Text Available The highlight of this study was the synthesis of nanopigmented poly(methyl methacrylate nanoparticles that were further processed using a water bath and/or microwave energy for dentures. The experimental acrylic resins were physicochemically characterized, and the adherence of Candida albicans and biocompatibility were assessed. A nanopigmented acrylic resin cured by a water bath or by microwave energy was obtained. The acrylic specimens possess similar properties to commercial acrylic resins, but the transverse strength and porosity were slightly improved. The acrylic resins cured with microwave energy exhibited reduced C. albicans adherence. These results demonstrate an improved noncytotoxic material for the manufacturing of denture bases in dentistry.

  12. In-situ photopolymerization of oriented liquid-crystalline acrylates

    NARCIS (Netherlands)

    Broer, Dirk Jan

    1990-01-01

    The scope of this thesis concerns a new method to produce oriented polymers by the in-situ photopolymerization of oriented liquid-crystalline acrylates. The desired macroscopic molecular order is already accomplished in the monomeric state prior to the polymerization. ... Zie: Summary

  13. Experimental investigation of the factors influencing the polymer-polymer bond strength during two component injection moulding

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Hansen, Hans Nørgaard; Tang, Peter Torben

    2007-01-01

    Two component injection moulding is a commercially important manufacturing process and a key technology for Moulded Interconnect Devices (MIDs). Many fascinating applications of two component or multi component polymer parts are restricted due to the weak interfacial adhesion of the polymers....... A thorough understanding of the factors that influence the bond strength of polymers is necessary for multi component polymer processing. This paper investigates the effects of the process and material parameters on the bond strength of two component polymer parts and identifies the factors which can...... effectively control the adhesion between two polymers. The effects of environmental conditions on the bond strength after moulding are also investigated. The material selections and environmental conditions were chosen based on the suitability of MID production, but the results and discussion presented...

  14. Experimental investigation of the factors influencing the polymer-polymer bond strength during two-component injection moulding

    DEFF Research Database (Denmark)

    Islam, Aminul; Hansen, Hans Nørgaard; Bondo, Martin

    2010-01-01

    ). Many fascinating applications of two-component or multi-component polymer parts are restricted due to the weak interfacial adhesion of the polymers. A thorough understanding of the factors that influence the bond strength of polymers is necessary for multi-component polymer processing. This paper...... investigates the effects of the process conditions and geometrical factors on the bond strength of two-component polymer parts and identifies the factors which can effectively control the adhesion between two polymers. The effects of environmental conditions on the bond strength are also investigated....... Investigation shows that melt and mould temperatures are vital process parameters that influence the bond strength. Besides this, surface roughness of the first-shot part and environmental factors like moisture have profound influence on the bonding of the two materials. The selections of materials...

  15. Waterborne hyperbranched alkyd-acrylic resin obtained by mini emulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Murillo, Edwin, E-mail: edwinalbertomurillo@gmail.com [Grupo de Investigacion en Materiales Polimericos (GIMAPOL), Universidad Francisco de Paula Santander, San Jose de Cucuta (Colombia); Lopez, Betty [Grupo de Investigacion en Ciencia de los Materiales, Universidad de Antioquia, Calle, Medellin (Colombia)

    2016-10-15

    Four waterborne hyper branched alkyd-acrylic resins (HBRAA) were synthesized by mini emulsion polymerization from a hyper branched alkyd resin (HBR), methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA), by using benzoyl peroxide (BPO) and ammonium persulfate (AP) as initiators. The reaction between HBR and acrylic monomers was evidenced by differential scanning calorimetric (DSC), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The conversion percentage, glass transition temperature (T{sub g}), content of acrylic polymer (determined by soxhlet extraction) and molecular weight increased with the content of acrylic monomers used in the synthesis. The main structure formed during the synthesis was the HBRAA. The analysis by dynamic light scattering (DLS) showed that the particle size distribution of HBRAA2, HBRAA3 and HBRAA4 resins were mainly mono modal. The film properties (gloss, flexibility, adhesion and drying time) of the HBRAA were good. (author)

  16. Effects of gel composition on the radiation induced density change in PAG polymer gel dosimeters: a model and experimental investigations

    Energy Technology Data Exchange (ETDEWEB)

    Hilts, M [Medical Physics, BC Cancer Agency-Vancouver Centre, Vancouver BC V6R 2B6 (Canada); Jirasek, A [Medical Physics, BC Cancer Agency-Vancouver Centre, Vancouver BC V6R 2B6 (Canada); Duzenli, C [Medical Physics, BC Cancer Agency-Fraser Valley Centre, Surrey BC V3V 1Z2 (Canada)

    2004-06-21

    Due to a density change that occurs in irradiated polyacrylamide gel (PAG), x-ray computed tomography (CT) has emerged as a feasible method of performing polymer gel dosimetry. However, applicability of the technique is currently limited by low sensitivity of the density change to dose. This work investigates the effect of PAG composition on the radiation induced density change and provides direction for future work in improving the sensitivity of CT polymer gel dosimetry. A model is developed that describes the PAG density change ({delta}{rho}{sub gel}) as a function of both polymer yield (%P) and an intrinsic density change, per unit polymer yield, that occurs on conversion of monomer to polymer ({delta}{rho}{sub polymer}). %P is a function of the fraction of monomer consumed and the weight fraction of monomer in the unirradiated gel (%T). Applying the model to experimental CT and Raman spectroscopic data, two important fundamental properties of the response of PAG density to dose ({delta}{rho}{sub gel} dose response) are discovered. The first property is that {delta}{rho}{sub polymer} depends on PAG %C (cross-linking fraction of total monomer) such that low and high %C PAGs exhibit a higher {delta}{rho}{sub polymer} than do more intermediate %C PAGs. This relationship is opposite to the relationship of polymer yield to %C and is explained by the effect of %C on the type of polymer formed. The second property is that the {delta}{rho}{sub gel} dose response is linearly dependent on %T. From the model, the inference is that, at least for %T{<=}12%, monomer consumption and {delta}{rho}{sub polymer} depend solely on %C. In terms of optimizing CT polymer gel dosimetry for high sensitivity, these results indicate that {delta}{rho}{sub polymer} can be expected to vary with each polymer gel system and thus should be considered when choosing a polymer gel for CT gel dosimetry. However, {delta}{rho}{sub polymer} and %P cannot be maximized simultaneously and maximizing %P

  17. Finite element analysis and experimental verification of Polymer reinforced CRC improved for close-in detonation

    DEFF Research Database (Denmark)

    Riisgaard, Benjamin; Georgakis, Christos; Stang, Henrik

    2007-01-01

    Compact Reinforced Composite, CRC, is a high-strength cement-based composite that holds an enormous flexural and energy-absorbing capacity due to the close-spaced high strength steel reinforcement and a high-strength cement-based fiber DSP matrix. The material has been used in various constructions...... without breaching. This paper introduces an efficient method for implementing high fractions of polymer shock reinforcement in a CRC element. Experimental tests and explicit finite element analysis is used to demonstrate the potentials of this material. This paper also provides the reader...

  18. Experimental Studies and Modeling of the Drying Kinetics of Multicomponent Polymer Films.

    Science.gov (United States)

    Velaga, Sitaram P; Nikjoo, Dariush; Vuddanda, Parameswara R

    2018-01-01

    The process of drying thin polymer films is an important operation that influences the film structure and solid state, and the stability of the product. The purpose of this work was to study and model the drying kinetics of multicomponent films based on two polymers: hydroxypropyl methylcellulose (HPMC, amorphous) and polyvinyl alcohol (PVA, semicrystalline). The isothermal drying kinetics of the films at different temperatures (40, 60, and 80°C) were studied using thermo-gravimetric analysis (TGA) and convection oven methods. Solid-state characterization tools used in the study included polarization and hot-stage microscopy, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The drying kinetics of HPMC and PVA films in the TGA apparatus and convection oven were comparable. The three-parameter (W max, τ, n) Hill equation successfully modeled the experimental drying kinetics. The time factor τ in the Hill equation nicely explained two drying phases in the films. Solid-state phase changes occurring in the films during dehydration had a bearing on the drying kinetics and mechanisms. TGA can be used as a simple tool to determine the end points in drying processes using ovens or tunnels. The three-parameter Hill equation explained the drying kinetics and diffusion mechanisms of the solvent through the polymer films for the first time. This study advances our understanding of film drying, in particular for pharmaceutically relevant thin films.

  19. Effects of gel composition on the radiation induced density change in PAG polymer gel dosimeters: a model and experimental investigations.

    Science.gov (United States)

    Hilts, M; Jirasek, A; Duzenli, C

    2004-06-21

    Due to a density change that occurs in irradiated polyacrylamide gel (PAG), x-ray computed tomography (CT) has emerged as a feasible method of performing polymer gel dosimetry. However, applicability of the technique is currently limited by low sensitivity of the density change to dose. This work investigates the effect of PAG composition on the radiation induced density change and provides direction for future work in improving the sensitivity of CT polymer gel dosimetry. A model is developed that describes the PAG density change (delta(rho)gel) as a function of both polymer yield (%P) and an intrinsic density change, per unit polymer yield, that occurs on conversion of monomer to polymer (delta(rho)polymer). %P is a function of the fraction of monomer consumed and the weight fraction of monomer in the unirradiated gel (%T). Applying the model to experimental CT and Raman spectroscopic data, two important fundamental properties of the response of PAG density to dose (delta(rho)gel dose response) are discovered. The first property is that delta(rho)polymer)depends on PAG %C (cross-linking fraction of total monomer) such that low and high %C PAGs exhibit a higher deltarho(polymer)than do more intermediate %C PAGs. This relationship is opposite to the relationship of polymer yield to %C and is explained by the effect of %C on the type of polymer formed. The second property is that the delta(rho)gel dose response is linearly dependent on %T. From the model, the inference is that, at least for %T < or = 2%, monomer consumption and delta(rho)polymer depend solely on %C. In terms of optimizing CT polymer gel dosimetry for high sensitivity, these results indicate that delta(rho)polymer can be expected to vary with each polymer gel system and thus should be considered when choosing a polymer gel for CT gel dosimetry. However, delta(rho)polymerand %P cannot be maximized simultaneously and maximizing %P, by choosing gels with intermediate %C and high %T, is found to have the

  20. Experimental approach to investigate the constrained recovery behavior of coiled monofilament polymer fibers

    Science.gov (United States)

    Mendes, S. S.; Nunes, L. C. S.

    2017-11-01

    The aim of this work is to propose a new approach for investigating the thermo-mechanical behavior of coiled oriented polymer fibers with fixed ends and promote an understanding of the actuation response of coiled polymers in constrained recovery applications. In the proposed experimental methodology, a coiled fiber was pre-stretched by 50% and the distance between its ends remained constant, then it was subjected to a heating-cooling cycle ranging from 30 °C to 120 °C and the induced restoring force was measured. Based on these measurements, axial deformation and shear strain were obtained from full-field displacements extracted by the digital image correlation method from images of the coiled fiber. Three coiled fibers with different initial pitch angles were manufactured, and samples with lengths of 15 mm and 20 mm were tested. Bias angles and coil radius were also estimated using the experimental data associated with the helical spring theory. Results show that significant shape changes can be noticed above the glass transition temperature (47 °C), and these changes induce variation in the resultant forces. The effects of thermal softening and thermal contraction for a modest negative thermal expansion coefficient became evident at temperatures ranging from ∼47 °C to ∼90 °C, while the response of a coiled homochiral polymer fiber was achieved at temperatures close to 90 °C. During the cooling process, saturated states of the axial deformation and shear strain of the coiled fibers were observed at temperatures between 120 °C and 100 °C.

  1. Experimental Characterization of Ionic Polymer Metal Composite as a Novel Fractional Order Element

    Directory of Open Access Journals (Sweden)

    Riccardo Caponetto

    2013-01-01

    Full Text Available Ionic polymer metal composites (IPMCs are electroactive materials made of ionic polymer thin membranes with platinum metallization on their surfaces. They are interesting materials due to not only their electromechanical applications as transducers but also to their electrochemical features and the relationship between the ionic/solvent current and the potential field. Their electrochemical properties thus suggest the possibility for exploiting them as compact fractional-order elements (FOEs with a view of defining fabrication processes and production strategies that assure the desired performances. In this paper, the experimental electrical characterization of a brand new IPMC setup in a fixed sandwich configuration is proposed. Two IPMC devices with different platinum absorption times (5 h and 20 h are characterized through experimental data: first, a preliminary linearity study is performed for a fixed input voltage amplitude in order to determine the frequency region where IPMC can be approximated as linear; then, a frequency analysis is carried out in order to identify a coherent fractional-order dynamics in the bode diagrams. Such analyses take the first steps towards a simplified model of IPMC as a compact electronic FOE for which the fractional exponent value depends on fabrication parameters as the absorption time.

  2. Potassium fulvate-modified graft copolymer of acrylic acid onto cellulose as efficient chelating polymeric sorbent.

    Science.gov (United States)

    Mohamed, Magdy F; Essawy, Hisham A; Ammar, Nabila S; Ibrahim, Hanan S

    2017-01-01

    Acrylic acid (AA) was graft copolymerized from cellulose (Cell) in presence of potassium fulvate (KF) in order to enhance the chemical activity of the resulting chelating polymer and the handling as well. Fourier transform infrared (FTIR) proved that KF was efficiently inserted and became a permanent part of the network structure of the sorbent in parallel during the grafting copolymerization. Scanning electron microscopy (SEM) revealed intact homogeneous structure with uniform surface. This indicates improvement of the handling, however, it was not the case for the graft copolymer of acrylic acid onto cellulose in absence of KF, which is known to be brittle and lacks mechanical integrity. Effective insertion of this co-interpenetrating agent provided more functional groups, such as OH and COOH, which improved the chelating power of the produced sorbent as found for the removal of Cu(2+) ions from its aqueous solutions (the removal efficiency reached ∼98.9%). Different models were used to express the experimental data. The results corroborated conformity of the pseudo-second order kinetic model and Langmuir isotherm model to the sorption process, which translates into dominance of the chemisorption. Regeneration of the chelating polymers under harsh conditions did not affect the efficiency of copper ions uptake up to three successive cycles. A thermodynamic investigation ensured exothermic nature of the adsorption process that became less favourable at higher temperatures. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. 21 CFR 177.1010 - Acrylic and modified acrylic plastics, semirigid and rigid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylic and modified acrylic plastics, semirigid... Acrylic and modified acrylic plastics, semirigid and rigid. Semirigid and rigid acrylic and modified acrylic plastics may be safely used as articles intended for use in contact with food, in accordance with...

  4. Control of colloidal CaCO3 suspension by using biodegradable polymers during fabrication

    Directory of Open Access Journals (Sweden)

    Nemany Abdelhamid Nemany Hanafy

    2015-03-01

    The aim of this work was to investigate the synthesis process of CaCO3 particles in different experimental conditions: calcium carbonate was produced in presence and in absence of water and with addition of appropriate polymers. In particular, chitosan (CHI and poly acrylic acid (PAA were chosen as biodegradable polymers whereas PSS and PAH were chosen as non-biodegradable polymers. Shape and diameter of particles were investigated by using transmission and scanning electron microscopy, elemental composition was inferred by energy dispersive X-ray analyses whereas their charges were explored by using zeta potential.

  5. Computational prediction and experimental selectivity coefficients for hydroxyzine and cetirizine molecularly imprinted polymer based potentiometric sensors

    Energy Technology Data Exchange (ETDEWEB)

    Azimi, Abolfazl; Javanbakht, Mehran, E-mail: mehranjavanbakht@gmail.com

    2014-02-17

    Graphical abstract: -- Highlights: •Possible configurations template/monomer complexes were designed and optimized. •Effect of the electrostatic force on the selectivity of MIPs was investigated. •A correlation between selectivity of sensors and a charge distribution was obtained. -- Abstract: In spite of the increasing usages number of molecularly imprinted polymers (MIPs) in many scientific applications, the theoretical aspects of participating intra molecular forces are not fully understood. This work investigates effects of the electrostatic force, the Mulliken charge and the role of cavity's backbone atoms on the selectivity of MIPs. Moreover, charge distribution, which is a computational parameter, was proposed for the prediction of the selectivity coefficients of MIP-based sensors. In the computational approaches and experimental study, methacrylic acid (MAA) was chosen as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross linker for hydroxyzine and cetirizine imprinted polymers. Ab initio, DFT B3LYP method was carried out on molecular optimization. With regard to results obtained from molecules optimization and hydrogen bonding properties, possible configurations of 1:n (n ≤ 5) template/monomer complexes were designed and optimized. The binding energy for each complex in gas phase was calculated. Depending on the most stable configuration, hydroxyzine and cetirizine imprinted polymer models were designed. The calculations including the porogen were also investigated. The theoretical charge distributions for the template and some potential interfering molecules were calculated. The results showed a correlation between the selectivity coefficients and the theoretical charge distributions. The results surprisingly show that charge distribution based model was able to predict the selectivity coefficients of MIP based potentiometric sensors.

  6. Diels-Alder Trapping of Photochemically Generated o-Quinodimethane Intermediates: An Alternative Route to Photocured Polymer Film Development

    Science.gov (United States)

    Tyson, Daniel S.; Ilhan, Faysal; Meador, Mary Ann B.; Smith, Dee Dee; Scheiman, Daniel A.; Meador, Michael A.

    2004-01-01

    Photolysis of o-methylphenyl ketones generates bis-o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions. This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis-(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate ester monomers for the development of acrylic ester copolymer blends. Irradiation of cyclohexanone solutions of the bis-(o-methylphenyl ketone)s and acrylate esters produce thin polymer films. Solid state 13C NMR data indicated 47- 100% reaction of the bis-(o-methylphenyl ketone)s, depending on experimental conditions, to yield the desired products. DSC and TGA analyses were performed to determine the glass transition temperature, T,, and onset of decomposition, Td, of the resulting polymer films. A statistical Design of Experiments approach was used to obtain a systematic understanding of the effects of experimental variables on the extent of polymerization and the final polymer properties.

  7. Electroactive behavior assessment of poly(acrylic acid)-graphene oxide composite hydrogel in the detection of cadmium

    NARCIS (Netherlands)

    Bejarano-Jimenez, A.; Escobar-Barrios, V.A.; Kleijn, J.M.; Oritz-Ledon, C.A.; Chazaro-Ruiz, L.F.

    2014-01-01

    Super absorbent polymers of acrylic acid-graphene oxide (PAA-GO) were synthesized with different percentage of chemical neutralization (0, 10, and 20%) of the acrylic acid monomer before its polymerization. The influence of their swelling and adsorption/desorption capacity of cadmium ions in aqueous

  8. Ionizing radiation-induced copolymerization of 2-ethylhexyl acrylate and acrylic acid and ionomer formation

    Science.gov (United States)

    Weaver, Alia

    The ionizing radiation-induced polymerization of acrylate esters is a technique employed for the curing of such materials for a variety of adhesive, coating, ink, and lithographic applications. The work presented in this dissertation involves the synthesis of a copolymer composed of 2-ethylhexyl acrylate (2-EHA) and acrylic acid (AA) using pulsed electron beam and gamma irradiation. The structure and synthesis kinetics of this copolymer were investigated by 1H nuclear magnetic resonance (NMR), electron pulse radiolysis with kinetic spectroscopic detection (PR-KSD), and Fourier transform infrared spectroscopy (FTIR). The effects of total dose, dose rate, and acrylic acid content on the polymerization reaction were studied. The conversion of 2-EHA monomer into polymer at a given total dose was found to be enhanced at lower dose rates and higher concentrations of acrylic acid. The pulse radiolysis investigation of the polymerization of 2-EHA and AA was performed through studies of four different types of systems: (i) neat 2-EHA, (ii) 2-EHA/methanol (MeOH) solutions, (iii) mixtures of 2-EHA and AA, and (iv) 2-EHA/AA/MeOH solutions. The build-up of carbon-centered neutral 2-EHA free radicals in neat 2-EHA was found to obey a second order rate law with a rate coefficient of ((7 +/- 3) x 108)epsilon EHA·, whereas in 2-EHA/AA mixtures it was found to obey a pseudo-first order rate law with a rate coefficient of (1.5 +/- 0.3) x 10 10 mol-1 dm3 s-1. This phenomenon is suggested to originate in the increased H+ ion concentration in the presence of acrylic acid, which leads to a faster neutralization step of 2-EHA radical anions as they are transformed into neutral free radicals during the initiation step of the reaction. An investigation of the formation of ion-containing copolymers (known as ionomers) was performed using the radiation-synthesized poly(2-EHA-co-AA) and iron cations. Verification of successful incorporation of iron into the copolymer was identified by an

  9. Experimental data on the properties of natural fiber particle reinforced polymer composite material

    Directory of Open Access Journals (Sweden)

    D. Chandramohan

    2017-08-01

    Full Text Available This paper presents an experimental study on the development of polymer bio-composites. The powdered coconut shell, walnut shells and Rice husk are used as reinforcements with bio epoxy resin to form hybrid composite specimens. The fiber compositions in each specimen are 1:1 while the resin and hardener composition 10:1 respectively. The fabricated composites were tested as per ASTM standards to evaluate mechanical properties such as tensile strength, flexural strength, shear strength and impact strength are evaluated in both with moisture and without moisture. The result of test shows that hybrid composite has far better properties than single fibre glass reinforced composite under mechanical loads. However it is found that the incorporation of walnut shell and coconut shell fibre can improve the properties.

  10. [Acrylic resin removable partial dentures

    NARCIS (Netherlands)

    Baat, C. de; Witter, D.J.; Creugers, N.H.J.

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of

  11. FT-IR, UV-vis, 1H and 13C NMR spectra and the equilibrium structure of organic dye molecule disperse red 1 acrylate: a combined experimental and theoretical analysis.

    Science.gov (United States)

    Cinar, Mehmet; Coruh, Ali; Karabacak, Mehmet

    2011-12-01

    This study reports the characterization of disperse red 1 acrylate compound by spectral techniques and quantum chemical calculations. The spectroscopic properties were analyzed by FT-IR, UV-vis, (1)H NMR and (13)C NMR techniques. FT-IR spectrum in solid state was recorded in the region 4000-400 cm(-1). The UV-vis absorption spectrum of the compound that dissolved in methanol was recorded in the range of 200-800 nm. The (1)H and (13)C NMR spectra were recorded in CDCl(3) solution. The structural and spectroscopic data of the molecule in the ground state were calculated using density functional theory (DFT) employing B3LYP exchange correlation and the 6-311++G(d,p) basis set. The vibrational wavenumbers were calculated and scaled values were compared with experimental FT-IR spectrum. A satisfactory consistency between the experimental and theoretical spectra was obtained and it shows that the hybrid DFT method is very useful in predicting accurate vibrational structure, especially for high-frequency region. The complete assignments were performed on the basis of the experimental results and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Isotropic chemical shifts were calculated using the gauge-invariant atomic orbital (GIAO) method. A study on the electronic properties were performed by timedependent DFT (TD-DFT) and CIS(D) approach. To investigate non linear optical properties, the electric dipole moment μ, polarizability α, anisotropy of polarizability Δα and molecular first hyperpolarizability β were computed. The linear polarizabilities and first hyperpolarizabilities of the studied molecule indicate that the compound can be a good candidate of nonlinear optical materials. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Engineering Nanoscale Polymers in Photovoltaics and Supercapacitors: Experimental and Theoretical Studies

    Science.gov (United States)

    Smolin, Yuriy Y.

    into tortuous electrode pores with aspect ratios of >10,000 while preserving the intrinsic pore structures, to retain the double layer capacitance, is very challenging. Therefore, similarly to the iCVD process, oxidative CVD (oCVD) was chosen to bypass the limited solubility of CPs to deposit thin conformal CP films onto porous electrodes. By controlling the oCVD deposition parameters, PANI films on the order of a few nm were integrated into carbide-derived-carbon (CDC) electrodes, leading to a doubling of the capacitance. This yielded a PANI-only capacitance of 690 F/g, close to the theoretical value of 750 F/g. This work also combined experiments with first-principles modeling to develop a model-guided design and optimization framework, allowing for optimal device design and the intelligent selection of polymer chemistries with minimal experimental investigations. For example, to determine the effects of PE chemistry on DSSC processes, parameter estimation and parametric sensitivity studies were conducted which indicated that a shift in the conduction band of TiO2 and a suppression of the back electron transfer at the dye-TiO2-PE interface was induced by the side group PE chemistry. Furthermore, optimal design specifications for a PE DSSC were calculated using the model, and optimally performing DSSCs were subsequently fabricated and tested, validating the model.

  13. Prediction of drug-polymer miscibility through the use of solubility parameter based Flory-Huggins interaction parameter and the experimental validation: PEG as model polymer.

    Science.gov (United States)

    Thakral, Seema; Thakral, Naveen K

    2013-07-01

    Important consideration for developing physically stable solid dispersion is miscibility of drug in carrier matrix. It is possible to predict thermodynamics of binary system through free energy calculations based on Flory-Huggins interaction parameter (χ(dp)). In present study, PEG 6000 as model polymer and dataset comprising commonly used drugs/excipients was selected. The three-dimensional solubility parameter based on group contribution method was utilized for systemic calculation of χ(dp) of the polymer with each compound in data set. On the basis of the values of χ(dp), it was possible to categorize all the compounds into three distinct categories, Types I and II: compounds predicted to be miscible and immiscible respectively with the polymer in all proportions and Type III: compounds expected to exhibit composition dependent miscibility behavior. The Bagley plot showed that majority of points for Type I fall in a region, which can approximately be delimited by a circle. Experimental verification through thermal analysis revealed that though it was possible to predict correctly miscibility behavior of Type II class compounds, distinction between Types I and III was less evident. Hence, solubility parameter based χ(dp) may be used as an initial tool for fast screening of immiscible combination of polymer and drug. Copyright © 2013 Wiley Periodicals, Inc.

  14. Theoretical and experimental investigation of the shape memory properties of an ionic polymer-metal composite

    Science.gov (United States)

    Shen, Qi; Palmre, Viljar; Kim, Kwang J.; Oh, Il-Kwon

    2017-04-01

    An ionic polymer-metal composite (IPMC) is typically based on a Nafion membrane with electrode plating on both sides and has a promising potential for biomimetic robotics, biomedical devices and human affinity applications. In this paper, the shape memory properties of IPMC were theoretically and experimentally studied. We presented the multiple shape memory properties of a Nafion cylinder. A physics based model of the IPMC was proposed. The free energy density theory was utilized to analyze the shape properties of the IPMC. To verify the model, IPMC samples with Nafion as the base membrane were prepared and experiments were conducted. A simulation of the model was performed and the results were compared with the experimental data. It was successfully demonstrated that the theoretical model can well explain the shape memory properties of the IPMC. The results showed that the reheat glass transition temperature of the IPMC is lower than the programming temperature. It was also found that the back-relaxation of the IPMC decreases as the programming temperature increases. The current study may be useful in order to better understand the shape memory effect of IPMC.

  15. Experimental analysis of reinforced concrete beams strengthened in bending with carbon fiber reinforced polymer

    Directory of Open Access Journals (Sweden)

    M. M. VIEIRA

    Full Text Available The use of carbon fiber reinforced polymer (CFRP has been widely used for the reinforcement of concrete structures due to its practicality and versatility in application, low weight, high tensile strength and corrosion resistance. Some construction companies use CFRP in flexural strengthening of reinforced concrete beams, but without anchor systems. Therefore, the aim of this study is analyze, through an experimental program, the structural behavior of reinforced concrete beams flexural strengthened by CFRP without anchor fibers, varying steel reinforcement and the amount of carbon fibers reinforcement layers. Thus, two groups of reinforced concrete beams were produced with the same geometric feature but with different steel reinforcement. Each group had five beams: one that is not reinforced with CFRP (reference and other reinforced with two, three, four and five layers of carbon fibers. Beams were designed using a computational routine developed in MAPLE software and subsequently tested in 4-point points flexural test up to collapse. Experimental tests have confirmed the effectiveness of the reinforcement, ratifying that beams collapse at higher loads and lower deformation as the amount of fibers in the reinforcing layers increased. However, the increase in the number of layers did not provide a significant increase in the performance of strengthened beams, indicating that it was not possible to take full advantage of strengthening applied due to the occurrence of premature failure mode in the strengthened beams for pullout of the cover that could have been avoided through the use of a suitable anchoring system for CFRP.

  16. Measuring the Biodegradability of Plastic Polymers in Olive-Mill Waste Compost with an Experimental Apparatus

    Directory of Open Access Journals (Sweden)

    Francesco Castellani

    2016-01-01

    Full Text Available The use of biodegradable polymers is spreading in agriculture to replace those materials derived from petroleum, thus reducing the environmental concerns. However, to issue a significant assessment, biodegradation rate must be measured in case-specific standardized conditions. In accordance with ISO 14855-1, we designed and used an experimental apparatus to evaluate the biodegradation rate of three biopolymers based on renewable resources, two poly(ε-caprolactone (PCL composites, and a compatibilized polylactic acid and polybutyrate (PLA/PBAT blend. Biodegradation tests were carried out under composting condition using mature olive-mill waste (OMW compost as inoculum. Carbon dioxide emissions were automatically recorded by infrared gas detectors and also trapped in saturated Ba(OH2 solution and evaluated via a standard titration method to check the results. Some of the samples reached more than 80% biodegradation in less than 20 days. Both the experimental apparatus and the OMW compost showed to be suitable for the cases studied.

  17. [Acrylic resin removable partial dentures].

    Science.gov (United States)

    de Baat, C; Witter, D J; Creugers, N H J

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of removable partial dentures, the acrylic resin removable partial denture has 3 favourable aspects: the economic aspect, its aesthetic quality and the ease with which it can be extended and adjusted. Disadvantages are an increased risk of caries developing, gingivitis, periodontal disease, denture stomatitis, alveolar bone reduction, tooth migration, triggering of the gag reflex and damage to the acrylic resin base. Present-day indications are ofa temporary or palliative nature or are motivated by economic factors. Special varieties of the acrylic resin removable partial denture are the spoon denture, the flexible denture fabricated of non-rigid acrylic resin, and the two-piece sectional denture. Furthermore, acrylic resin removable partial dentures can be supplied with clasps or reinforced by fibers or metal wires.

  18. Numerical Simulation and Experimental Investigation of the Viscoelastic Heating Mechanism in Ultrasonic Plasticizing of Amorphous Polymers for Micro Injection Molding

    Directory of Open Access Journals (Sweden)

    Bingyan Jiang

    2016-05-01

    Full Text Available Ultrasonic plasticizing of polymers for micro-injection molding has been proposed and studied for its unique potential in materials and energy-saving. In our previous work, we have demonstrated the characteristics of the interfacial friction heating mechanism in ultrasonic plasticizing of polymer granulates. In this paper, the other important heating mechanism in ultrasonic plasticizing, i.e., viscoelastic heating for amorphous polymer, was studied by both theoretical modeling and experimentation. The influence mechanism of several parameters, such as the initial temperature of the polymer, the ultrasonic frequency, and the ultrasonic amplitude, was investigated. The results from both numerical simulation and experimentation indicate that the heat generation rate of viscoelastic heating can be significantly influenced by the initial temperature of polymer. The glass transition temperature was found to be a significant shifting point in viscoelastic heating. The heat generation rate is relatively low at the beginning and can have a steep increase after reaching glass transition temperature. In comparison with the ultrasonic frequency, the ultrasonic amplitude has much greater influence on the heat generation rate. In light of the quantitative difference in the viscoelastic heating rate, the limitation of the numerical simulation was discussed in the aspect of the assumptions and the applied mathematical models.

  19. Theoretical and experimental research on the self-assembled system of molecularly imprinted polymers formed by salbutamol and methacrylic acid.

    Science.gov (United States)

    Jun-Bo, Liu; Yang, Shi; Shan-Shan, Tang; Rui-Fa, Jin

    2015-03-01

    The quantum chemical method was applied for screening functional monomers in the rational design of salbutamol-imprinted polymers. Salbutamol was the template molecule, and methacrylic acid was the single functional monomer. The LC-WPBE/6-31G(d,p) method was used to investigate the geometry optimization, active sites, natural bond orbital charges, binding energies of the imprinted molecule, and solvation energy. The mechanism of action between salbutamol and methacrylic acid was also discussed. The theoretical results show that salbutamol interacts with functional monomers by hydrogen bonds, and the salbutamol-imprinted polymers with a ratio of 1:4 (salbutamol/methacrylic acid) in acetonitrile had the highest stability. The salbutamol-imprinted polymers were prepared by precipitation polymerization. The experimental results indicated that the maximum adsorption capacity for salbutamol toward molecularly imprinted polymers was 7.33 mg/g, and the molecularly imprinted polymers had a higher selectivity for salbutamol than for norepinephrine and terbutaline sulfate. Herein, the studies can provide theoretical and experimental references for the salbutamol molecular imprinted system. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Facile Fabrication of Gradient Surface Based on (meth)acrylate Copolymer Films

    Science.gov (United States)

    Zhang, Y.; Yang, H.; Wen, X.-F.; Cheng, J.; Xiong, J.

    2016-08-01

    This paper describes a simple and economic approach for fabrication of surface wettability gradient on poly(butyl acrylate - methyl methacrylate) [P (BA-MMA)] and poly(butyl acrylate - methyl methacrylate - 2-hydroxyethyl methacrylate) [P (BA-MMA-HEMA)] films. The (meth)acrylate copolymer [including P (BA-MMA) and P (BA-MMA-HEMA)] films are hydrolyzed in an aqueous solution of NaOH and the transformation of surface chemical composition is achieved by hydrolysis in NaOH solution. The gradient wetting properties are generated based on different functional groups on the P (BA-MMA) and P (BA-MMA-HEMA) films. The effects of both the surface chemical and surface topography on wetting of the (meth)acrylate copolymer film are discussed. Surface chemical composition along the materials length is determined by XPS, and surface topography properties of the obtained gradient surfaces are analyzed by FESEM and AFM. Water contact angle system (WCAs) results show that the P (BA-MMA-HEMA) films provide a larger slope of the gradient wetting than P (BA-MMA). Moreover, this work demonstrates that the gradient concentration of chemical composition on the poly(meth) acrylate films is owing to the hydrolysis processes of ester group, and the hydrolysis reactions that have negligible influence on the surface morphology of the poly(meth) acrylate films coated on the glass slide. The gradient wettability surfaces may find broad applications in the field of polymer coating due to the compatibility of (meth) acrylate polymer.

  1. Characterization of methacrylated alginate and acrylic monomers as versatile SAPs.

    Science.gov (United States)

    Mignon, Arn; Vermeulen, Jolien; Graulus, Geert-Jan; Martins, José; Dubruel, Peter; De Belie, Nele; Van Vlierberghe, Sandra

    2017-07-15

    Superabsorbent polymers (SAPs) based on polysaccharides, especially alginate, could offer a valuable solution in a plethora of applications going from drug delivery to self-healing concrete. This has already been proven with both calcium alginate and methacrylated alginate combined with acrylic acid. In this manuscript, the effect of varying the degree of methacrylation and use of a combination of acrylic acid and acrylamide is investigated to explore the effects on the relevant SAP characteristics. The materials showed high gel fractions and a strong swelling capacity up to 630gwater/gSAP, especially for superabsorbent polymers with a low degree of substitution. The SAPs also showed only a limited hydrolysis in aqueous and cement filtrate solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Synthesis of Radiation Curable Palm Oil–Based Epoxy Acrylate: NMR and FTIR Spectroscopic Investigations

    Directory of Open Access Journals (Sweden)

    Ashraf M. Salih

    2015-08-01

    Full Text Available Over the past few decades, there has been an increasing demand for bio-based polymers and resins in industrial applications, due to their potential lower cost and environmental impact compared with petroleum-based counterparts. The present research concerns the synthesis of epoxidized palm oil acrylate (EPOLA from an epoxidized palm oil product (EPOP as environmentally friendly material. EPOP was acrylated by acrylic acid via a ring opening reaction. The kinetics of the acrylation reaction were monitored throughout the reaction course and the acid value of the reaction mixture reached 10 mg KOH/g after 16 h, indicating the consumption of the acrylic acid. The obtained epoxy acrylate was investigated intensively by means of FTIR and NMR spectroscopy, and the results revealed that the ring opening reaction was completed successfully with an acrylation yield about 82%. The UV free radical polymerization of EPOLA was carried out using two types of photoinitiators. The radiation curing behavior was determined by following the conversion of the acrylate groups. The cross-linking density and the hardness of the cured EPOLA films were measured to evaluate the effect of the photoinitiator on the solid film characteristics, besides, the thermal and mechanical properties were also evaluated.

  3. Synthesis of Radiation Curable Palm Oil-Based Epoxy Acrylate: NMR and FTIR Spectroscopic Investigations.

    Science.gov (United States)

    Salih, Ashraf M; Ahmad, Mansor Bin; Ibrahim, Nor Azowa; Dahlan, Khairul Zaman Hj Mohd; Tajau, Rida; Mahmood, Mohd Hilmi; Yunus, Wan Md Zin Wan

    2015-08-04

    Over the past few decades, there has been an increasing demand for bio-based polymers and resins in industrial applications, due to their potential lower cost and environmental impact compared with petroleum-based counterparts. The present research concerns the synthesis of epoxidized palm oil acrylate (EPOLA) from an epoxidized palm oil product (EPOP) as environmentally friendly material. EPOP was acrylated by acrylic acid via a ring opening reaction. The kinetics of the acrylation reaction were monitored throughout the reaction course and the acid value of the reaction mixture reached 10 mg KOH/g after 16 h, indicating the consumption of the acrylic acid. The obtained epoxy acrylate was investigated intensively by means of FTIR and NMR spectroscopy, and the results revealed that the ring opening reaction was completed successfully with an acrylation yield about 82%. The UV free radical polymerization of EPOLA was carried out using two types of photoinitiators. The radiation curing behavior was determined by following the conversion of the acrylate groups. The cross-linking density and the hardness of the cured EPOLA films were measured to evaluate the effect of the photoinitiator on the solid film characteristics, besides, the thermal and mechanical properties were also evaluated.

  4. Cross-sensitization patterns in acrylate allergies.

    Science.gov (United States)

    Jordan, W P

    1975-01-01

    Five subjects developed allergic contact dermatitis to one or more acrylate components used in a commercial adhesive tape. Patch testing to acrylic monomers was performed to examine their cross-reaction patterns. Two subjects with broad cross-reactions to acrylates did not react to methyl methacrylate or the alkyl methacrylate that corresponded to the acrylate which induced the sensitization. Methyl methacrylate may not be adequate as a screen for many acrylates used commercially.

  5. Synthesis and characterization of partially fluorinated poly(acryl) ionomers for polymer electrolyte membrane fuel cells and ESR-spectroscopic investigation of the radically induced degradation of model compounds; Synthese und Charakterisierung teilfluorierter Poly(acryl)-Ionomere als Polymerelektrolytmembranen fuer Brennstoffzellen und ESR-spektroskopische Untersuchung der radikalinduzierten Degradation von Modellverbindungen

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberger, Frank

    2008-07-09

    In the first part of this work different strategies for the design of sulfonated partially fluorinated poly(aryl)s are developed and synthetically realized. The applied concept is that partially fluorinated poly(aryl)s are distinguished from the nonfluorinated ones by an enhanced acidity. Moreover they possess higher bond dissociation energies of both the C-F bonds and any adjacent C-H bonds which should be associated with a gain in radical stability and thus in chemical and thermal stability. In order to investigate the influence of the chemical structure of (partially fluorinated) monomeric building blocks, homo-polymers with different structural units (with aromatic C-F bonds, C(CF3)2-bridged and/or CF3-substituted phenylene rings) are synthesized by polycondensation and structurally characterized (elemental analysis, NMR spectroscopy, gel permeation chromatography). Established organic reactions, such as the Balz-Schiemann reaction, Suzuki reaction and Ullmann's biaryl synthesis, are applied for the synthesis of the specific monomers. After sulfonation of the homo-polymers (ionically crosslinked) membranes are prepared and characterized in terms of suitability as polymer electrolyte membrane in fuel cells (ion-exchange capacity, proton conductivity, thermal and chemical stability, water uptake, dimensional change). Both the chemical nature of the monomers and their constitution in the ionomer are important for the properties of the resulting membranes. Therefore microphase-separated multiblock-co-ionomers based on hydrophilic (sulfonated) and hydrophobic (partially fluorinated) telechelic macromonomers are prepared and characterized. Both the influence of the block length and the chemical nature of the used monomers on the membrane properties are comparatively investigated. On the basis of the findings gained in this part of the work, the advantages and disadvantages of partially fluorinated ionomer membranes are analyzed and discussed. The second part of

  6. Two decades of occupational (meth)acrylate patch test results and focus on isobornyl acrylate

    NARCIS (Netherlands)

    Christoffers, Wietske A; Coenraads, Pieter Jan; Schuttelaar, Marie-Louise A

    BACKGROUND: Acrylates constitute an important cause of occupational contact dermatitis. Isobornyl acrylate sensitization has been reported in only 2 cases. We encountered an industrial process operator with occupational contact dermatitis caused by isobornyl acrylate. OBJECTIVES: (i) To investigate

  7. From Interfaces to Bulk: Experimental-Computational Studies Across Time and Length Scales of Multi-Functional Ionic Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Perahia, Dvora [Clemson Univ., SC (United States); Grest, Gary S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-01-25

    Neutron experiments coupled with computational components have resulted in unprecedented understanding of the factors that impact the behavior of ionic structured polymers. Additionally, new computational tools to study macromolecules, were developed. In parallel, this DOE funding have enabled the education of the next generation of material researchers who are able to take the advantage neutron tools offer to the understanding and design of advanced materials. Our research has provided unprecedented insight into one of the major factors that limits the use of ionizable polymers, combining the macroscopic view obtained from the experimental techniques with molecular insight extracted from computational studies leading to transformative knowledge that will impact the design of nano-structured, materials. With the focus on model systems, of broad interest to the scientific community and to industry, the research addressed challenges that cut across a large number of polymers, independent of the specific chemical structure or the transported species.

  8. Fabrication of a stand-alone polymer microlens: design of molding apparatus, simulation and experimental results

    Science.gov (United States)

    Mirkhalaf, M.; Tor, S. B.; Murukeshan, V. M.; Loh, N. H.; Lye, S. W.

    2009-09-01

    Micron size lenses and microlens arrays are new products that are attracting the attention of the scientific community for their possible outstanding applications. Wide applications of microlens arrays, self-standing microlenses for biomedical applications, arrayed device coupling and parallel optical image processing have been reported in the recent past. Though many techniques have been utilized and well established to fabricate microlens arrays, mass production of polymer self-standing micro imaging lenses is still a challenge. This paper in this context discusses the design and development of a precision compression molding apparatus for the fabrication of stand-alone microlenses. Finite element method (FEM) simulation was used to predict the profile of the lens and the residual stresses, which could influence the optical characteristics. The FEM simulation results are in good agreement with the experimental results. Different types of characterization equipment were used to determine both the geometrical and the optical properties of the molded lens. It was observed that the geometrical properties of the molded lens match well with the mold inserts and the optical properties are found to be suitable for the intended applications.

  9. Experimental research and statistic analysis of polymer composite adhesive joints strength

    Science.gov (United States)

    Rudawska, Anna; Miturska, Izabela; Szabelski, Jakub; Skoczylas, Agnieszka; Droździel, Paweł; Bociąga, Elżbieta; Madleňák, Radovan; Kasperek, Dariusz

    2017-05-01

    The aim of this paper is to determine the effect of arrangement of fibreglass fabric plies in a polymer composite on adhesive joint strength. Based on the experimental results, the real effect of plies arrangement and their most favourable configuration with respect to strength is determined. The experiments were performed on 3 types of composites which had different fibre orientations. The composites had three plies of fabric. The plies arrangement in Composite I was unchanged, in Composite II the central ply had the 45° orientation, while in Composite III the outside ply (tangential to the adhesive layer) was oriented at 45°. Composite plates were first cut into smaller specimens and then adhesive-bonded in different combinations with Epidian 61/Z1/100:10 epoxy adhesive. After stabilizing, the single-lap adhesive joints were subjected to shear strength tests. It was noted that plies arrangement in composite materials affects the strength of adhesive joints made of these composites between the values of the strength of the confidence level of 0.95. The statistical analysis of the results also showed that there are no statistical significant differences in average values of surface free energy (0.95 confidence level).

  10. Temperature Mapping of 3D Printed Polymer Plates: Experimental and Numerical Study

    Directory of Open Access Journals (Sweden)

    Charoula Kousiatza

    2017-02-01

    Full Text Available In Fused Deposition Modeling (FDM, which is a common thermoplastic Additive Manufacturing (AM method, the polymer model material that is in the form of a flexible filament is heated above its glass transition temperature (Tg to a semi-molten state in the head’s liquefier. The heated material is extruded in a rastering configuration onto the building platform where it rapidly cools and solidifies with the adjoining material. The heating and rapid cooling cycles of the work materials exhibited during the FDM process provoke non-uniform thermal gradients and cause stress build-up that consequently result in part distortions, dimensional inaccuracy and even possible part fabrication failure. Within the purpose of optimizing the FDM technique by eliminating the presence of such undesirable effects, real-time monitoring is essential for the evaluation and control of the final parts’ quality. The present work investigates the temperature distributions developed during the FDM building process of multilayered thin plates and on this basis a numerical study is also presented. The recordings of temperature changes were achieved by embedding temperature measuring sensors at various locations into the middle-plane of the printed structures. The experimental results, mapping the temperature variations within the samples, were compared to the corresponding ones obtained by finite element modeling, exhibiting good correlation.

  11. Experimental dissection of oxygen transport resistance in the components of a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Oh, Hwanyeong; Lee, Yoo il; Lee, Guesang; Min, Kyoungdoug; Yi, Jung S.

    2017-03-01

    Oxygen transport resistance is a major obstacle for obtaining high performance in a polymer electrolyte membrane fuel cell (PEMFC). To distinguish the major components that inhibit oxygen transport, an experimental method is established to dissect the oxygen transport resistance of the components of the PEMFC, such as the substrate, micro-porous layer (MPL), catalyst layer, and ionomer film. The Knudsen numbers are calculated to determine the types of diffusion mechanisms at each layer by measuring the pore sizes with either mercury porosimetry or BET analysis. At the under-saturated condition where condensation is mostly absent, the molecular diffusion resistance is dissected by changing the type of inert gas, and ionomer film permeation is separated by varying the inlet gas humidity. Moreover, the presence of the MPL and the variability of the substrate thickness allow the oxygen transport resistance at each component of a PEMFC to be dissected. At a low relative humidity of 50% and lower, an ionomer film had the largest resistance, while the contribution of the MPL was largest for the other humidification conditions.

  12. Temperature Mapping of 3D Printed Polymer Plates: Experimental and Numerical Study.

    Science.gov (United States)

    Kousiatza, Charoula; Chatzidai, Nikoleta; Karalekas, Dimitris

    2017-02-24

    In Fused Deposition Modeling (FDM), which is a common thermoplastic Additive Manufacturing (AM) method, the polymer model material that is in the form of a flexible filament is heated above its glass transition temperature (Tg) to a semi-molten state in the head's liquefier. The heated material is extruded in a rastering configuration onto the building platform where it rapidly cools and solidifies with the adjoining material. The heating and rapid cooling cycles of the work materials exhibited during the FDM process provoke non-uniform thermal gradients and cause stress build-up that consequently result in part distortions, dimensional inaccuracy and even possible part fabrication failure. Within the purpose of optimizing the FDM technique by eliminating the presence of such undesirable effects, real-time monitoring is essential for the evaluation and control of the final parts' quality. The present work investigates the temperature distributions developed during the FDM building process of multilayered thin plates and on this basis a numerical study is also presented. The recordings of temperature changes were achieved by embedding temperature measuring sensors at various locations into the middle-plane of the printed structures. The experimental results, mapping the temperature variations within the samples, were compared to the corresponding ones obtained by finite element modeling, exhibiting good correlation.

  13. Temperature Mapping of 3D Printed Polymer Plates: Experimental and Numerical Study

    Science.gov (United States)

    Kousiatza, Charoula; Chatzidai, Nikoleta; Karalekas, Dimitris

    2017-01-01

    In Fused Deposition Modeling (FDM), which is a common thermoplastic Additive Manufacturing (AM) method, the polymer model material that is in the form of a flexible filament is heated above its glass transition temperature (Tg) to a semi-molten state in the head’s liquefier. The heated material is extruded in a rastering configuration onto the building platform where it rapidly cools and solidifies with the adjoining material. The heating and rapid cooling cycles of the work materials exhibited during the FDM process provoke non-uniform thermal gradients and cause stress build-up that consequently result in part distortions, dimensional inaccuracy and even possible part fabrication failure. Within the purpose of optimizing the FDM technique by eliminating the presence of such undesirable effects, real-time monitoring is essential for the evaluation and control of the final parts’ quality. The present work investigates the temperature distributions developed during the FDM building process of multilayered thin plates and on this basis a numerical study is also presented. The recordings of temperature changes were achieved by embedding temperature measuring sensors at various locations into the middle-plane of the printed structures. The experimental results, mapping the temperature variations within the samples, were compared to the corresponding ones obtained by finite element modeling, exhibiting good correlation. PMID:28245557

  14. Two decades of occupational (meth)acrylate patch test results and focus on isobornyl acrylate

    OpenAIRE

    Christoffers, Wietske A; Coenraads, Pieter Jan; Schuttelaar, Marie-Louise A

    2013-01-01

    BACKGROUND: Acrylates constitute an important cause of occupational contact dermatitis. Isobornyl acrylate sensitization has been reported in only 2 cases. We encountered an industrial process operator with occupational contact dermatitis caused by isobornyl acrylate. OBJECTIVES: (i) To investigate whether it is relevant to add isobornyl acrylate to the (meth)acrylate test series. (ii) To report patients with (meth)acrylate contact allergy at an occupational dermatology clinic. PATIENTS/MATER...

  15. Large deformation micromechanics of particle filled acrylics at elevated temperatures

    Science.gov (United States)

    Gunel, Eray Mustafa

    The main aim of this study is to investigate stress whitening and associated micro-deformation mechanism in thermoformed particle filled acrylic sheets. For stress whitening quantification, a new index was developed based on image histograms in logarithmic scale of gray level. Stress whitening levels in thermoformed acrylic composites was observed to increase with increasing deformation limit, decreasing forming rate and increasing forming temperatures below glass transition. Decrease in stress whitening levels above glass transition with increasing forming temperature was attributed to change in micro-deformation behavior. Surface deformation feature investigated with scanning electron microscopy showed that source of stress whitening in thermoformed samples was a combination of particle failure and particle disintegration depending on forming rate and temperature. Stress whitening level was strongly correlated to intensity of micro-deformation features. On the other hand, thermoformed neat acrylics displayed no surface discoloration which was attributed to absence of micro-void formation on the surface of neat acrylics. Experimental damage measures (degradation in initial, secant, unloading modulus and strain energy density) have been inadequate in describing damage evolution in successive thermoforming applications on the same sample at different levels of deformation. An improved version of dual-mechanism viscoplastic material model was proposed to predict thermomechanical behavior of neat acrylics under non-isothermal conditions. Simulation results and experimental results were in good agreement and failure of neat acrylics under non-isothermal conditions ar low forming temperatures were succesfully predicted based on entropic damage model. Particle and interphase failure observed in acrylic composites was studied in a multi-particle unit cell model with different volume fractions. Damage evolution due to particle failure and interphase failure was simulated

  16. Experimental investigation for graphene and carbon fibre in polymer-based matrix for structural applications

    Directory of Open Access Journals (Sweden)

    Shankar A. Hallad

    2017-06-01

    Full Text Available The present paper investigates the behaviour of a polymer matrix beam reinforced with graphene and carbon fibres at nano and micro level reinforcements, respectively, to study mainly the strength aspects for structural applications. However an attempt has also been made to use a combination of both micro and nano level fillers in both individual and combined forms as reinforcements. The addition of graphene and carbon fibres in the control beams was varied from 0.1 to 0.4% percent by weight of polymer matrix. Dispersion of graphene was carried out using ultrasonic energy. Composite beams were tested under flexural in order to evaluate their mechanical property such as load-deflection criteria. These results were then compared with those obtained from plain polymer beams. The present work also investigates the optimum percentage of graphene and carbon fibres as individual and combination fillers that gave the best results in terms of enhanced mechanical properties and economical aspects as well. Scanning electron microscopy and energy dispersion X-ray spectroscopy was conducted to examine the interfacial surface adhesion between the fillers and the polymer matrix. Reinforcement of polymer beams with graphene alone by weight of the polymer matrix showed enhanced results when compared to carbon fibres alone while the use of combined nano and micro reinforcements showed performance lying in between nano and micro fillers in the polymer. Flexural strength is enhanced by 35% compared to plain control beams when graphene was used as reinforcement fillers in the polymer matrix.

  17. Crosslinkers of Different Types in Precipitation Polymerization of Acrylic Acid

    Directory of Open Access Journals (Sweden)

    H. Eshaghi

    2013-01-01

    Full Text Available Crosslinked poly(acrylic acids were prepared using two types of crosslinker by precipitation polymerization method in a binary organic solvent. N,N’-methylenebisacrylamide (MBA and polyethylene glycol dimethacrylate (PEGDMA-330 were used as low-molecular weight and long-chain crosslinkers, respectively. The effect of various types of crosslinkers on polymer characteristics (i.e., gel content, equilibrium swelling, glass transition temperature, and rheological properties was investigated. Maximum amount of viscosity was obtained by using long-chain crosslinker. The Flory-Rehner equation and rubber elasticity theory were used to discuss the network structure of polymer. It was observed that, the glass transition temperature (Tg of the synthesized polymer containing PEGDMA-330 is higher than that of polymer containing MBA. Apparent and rotational viscosity were used to determine the optimal crosslinker type. In addition, the consistencycoefficient (m and flow behavior index (n parameter of Ostwald equation were investigated as well.

  18. Control and experimental characterization of a methanol reformer for a 350 W high temperature polymer electrolyte membrane fuel cell system

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen; Sahlin, Simon Lennart

    2013-01-01

    This work presents a control strategy for controlling the methanol reformer temperature of a 350 W high temperature polymer electrolyte membrane fuel cell system, by using a cascade control structure for reliable system operation. The primary states affecting the methanol catalyst bed temperature...... is the water and methanol mixture fuel flow and the burner fuel/air ratio and combined flow. An experimental setup is presented capable of testing the methanol reformer used in the Serenergy H3 350 Mobile Battery Charger; a high temperature polymer electrolyte membrane (HTPEM) fuel cell system....... The experimental system consists of a fuel evaporator utilizing the high temperature waste gas from the cathode air cooled 45 cell HTPEM fuel cell stack. The fuel cells used are BASF P1000 MEAs which use phosphoric acid doped polybenzimidazole membranes. The resulting reformate gas output of the reformer system...

  19. Pharmacokinetics of an oral extended-release formulation of doxycycline hyclate containing acrylic acid and polymethacrylate in dogs.

    Science.gov (United States)

    Ruiz, Sara Melisa Arciniegas; Olvera, Lilia Gutiérrez; Chacón, Sara del Carmen Caballero; Estrada, Dinorah Vargas

    2015-04-01

    To determine the pharmacokinetics of doxycycline hyclate administered orally in the form of experimental formulations with different proportions of acrylic acid-polymethacrylate-based matrices. 30 healthy adult dogs. In a crossover study, dogs were randomly assigned (in groups of 10) to receive a single oral dose (20 mg/kg) of doxycycline hyclate without excipients (control) or extended-release formulations (ERFs) containing doxycycline, acrylic acid polymer, and polymethacrylate in the following proportions: 1:0.5:0.0075 (ERF1) or 1:1:0.015 (ERF2). Serum concentrations of doxycycline were determined for pharmacokinetic analysis before and at several intervals after each treatment. Following oral administration to the study dogs, each ERF resulted in therapeutic serum doxycycline concentrations for 48 hours, whereas the control treatment resulted in therapeutic serum doxycycline concentrations for only 24 hours. All pharmacokinetic parameters for ERF1 and ERF2 were significantly different; however, findings for ERF1 did not differ significantly from those for the control treatment. Results indicated that both ERFs containing doxycycline, acrylic acid polymer, and polymethacrylate had an adequate pharmacokinetic-pharmacodynamic relationship for a time-dependent drug and a longer release time than doxycycline alone following oral administration in dogs. Given the minimum effective serum doxycycline concentration of 0.26 μg/mL, a dose interval of 48 hours can be achieved for each tested ERF. This minimum inhibitory concentration has the potential to be effective against several susceptible bacteria involved in important infections in dogs. Treatment of dogs with either ERF may have several benefits over treatment with doxycycline alone.

  20. Experimental Study of Concrete-filled Carbon Fiber Reinforced Polymer Tube with Internal Reinforcement under Axially Loading

    OpenAIRE

    SUN Wenbin; Qiangqiang ZHU; Weizhong HE

    2014-01-01

    Comparing with the circular concrete columns confined with fiber reinforced polymer (FRP) wrap or tube, the rectilinear confined columns were reported much less. Due to the non-uniform distribution of confining pressure in the rectilinear confined columns, the FRP confinement effectiveness was significant reduced. This paper presents findings of an experimental program where nine prefabricated rectangular cross-section CFRP tubes with CFRP integrated crossties filled concrete to form concrete...

  1. Experimental Study on the Properties and Displacement Effects of Polymer Surfactant Solution

    Directory of Open Access Journals (Sweden)

    Ke-Liang Wang

    2013-01-01

    Full Text Available Based on the characteristics of oil reservoirs and the requirements of further enhancing oil recovery at high water cut stage of Pubei Oilfield, the displacement performance of polymer surfactant is evaluated. Reasonable injection parameters and oil displacement effects after water flooding are also researched. Compared with conventional polymer with intermediate molecular weight, polymer surfactant has the properties of higher viscosity at low concentration condition and lower interfacial tension. Laboratory experiments indicate that the displacement effect of polymer surfactant is much better than that of conventional polymer at a slug size of 0.57 PV. The oil recovery of polymer surfactant increases by more than 10% after water flooding. Considering the actual situation of low-permeability of Pubei Oilfield reservoirs, the system viscosity of 30 mPa·s is chosen. The corresponding concentration of Type III polymer surfactant is 600 mg/L and the injected slug is 0.57 PV and the oil recovery can be increased by 11.69%.

  2. Experimental study on the performance of a variable optical attenuator using polymer dispersed liquid crystal.

    Science.gov (United States)

    Nabil, Ghada; Ho, Wing Fat; Chan, Hau Ping

    2013-08-01

    We applied polymer dispersed liquid crystal (PDLC) as the cladding material in a polymer-based variable optical attenuator. Three polymer inverted channel waveguides were fabricated, two with PDLC upper cladding (aligned PDLC and nonaligned PDLC) and one with aligned liquid crystal upper cladding. Upon operation, the waveguides with aligned upper claddings show relatively lower threshold and cutoff voltages compared to those with nonaligned PDLC cladding. But the waveguide with nonaligned PDLC upper cladding shows lower polarization dependence and a higher attenuation range of 39 and 41.37 dB for TM and TE modes, respectively, over a tuning field strength of 0.9 V/μm.

  3. Bonding auto-polymerising acrylic resin to acrylic denture teeth.

    LENUS (Irish Health Repository)

    Nagle, Susan

    2009-09-01

    This study investigated the effect of surface treatments on the shear bond strength of an auto-polymerising acrylic resin cured to acrylic denture teeth. The surface treatments included a combination of grit-blasting and\\/or wetting the surface with monomer. Samples were prepared and then stored in water prior to shear testing. The results indicated that the application of monomer to the surface prior to bonding did not influence the bond strength. Grit blasting was found to significantly increase the bond strength.

  4. Theory and characteristics of holographic polymer dispersed liquid crystal transmission grating with scaffolding morphology.

    Science.gov (United States)

    Huang, Wenbin; Liu, Yonggang; Diao, Zhihui; Yang, Chengliang; Yao, Lishuang; Ma, Ji; Xuan, Li

    2012-06-20

    We have performed a detailed characterization of the optical properties of a holographic polymer dispersed liquid crystal (LC) transmission grating with polymer scaffolding morphology, which was fabricated with conventional high-functionality acrylate monomer under low curing intensity. Temporal evolution of the grating formation was investigated, and the amount of phase-separated LC was determined by birefringence investigation. A grating model combined with anisotropic coupled-wave theory yielded good agreement with experimental data without any fitting parameter. The results in this study demonstrate the non droplet scaffolding morphology grating is characterized by a high degree of phase separation (70%), high anisotropy, low scattering loss (<6%), and high diffraction efficiency (95%).

  5. Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

    National Research Council Canada - National Science Library

    Zhou, Jie; Blair, Barry; Argires, John; Pitsch, Donald

    2015-01-01

    .... Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP...

  6. Experimental studies of the dynamic mechanical response of a single polymer chain

    DEFF Research Database (Denmark)

    Thormann, Esben; Evans, Drew R.; Craig, Vincent S. J.

    2006-01-01

    The high-frequency and low-amplitude dynamic mechanical response from a single poly(vinyl alcohol) chain was investigated. Modification of a commercial atomic force microscope enabled high-frequency and low-amplitude periodic deformations of polymer chains during extension to be performed....... Such an experiment has previously been considered untenable due to hydrodynamic and viscous effects, but we introduce here a method to isolate the response of the polymer from the hydrodynamic response. For periodic deformations with frequencies of 400-2000 Hz and amplitudes of 0.55-16.9 nm, we find that the dynamic...... mechanical response from poly(vinyl alcohol) does not differ from its static response. This result is not unexpected as poly(vinyl alcohol) is a highly flexible polymer with intramolecular relaxation processes taking place on a short time scale. The choice of a polymer with a fast relaxation allows its...

  7. FT-IR and FT-Raman studies of cross-linking processes with Ca(2+) ions, glutaraldehyde and microwave radiation for polymer composition of poly(acrylic acid)/sodium salt of carboxymethyl starch--part I.

    Science.gov (United States)

    Grabowska, Beata; Sitarz, Maciej; Olejnik, Ewa; Kaczmarska, Karolina

    2015-01-25

    FT-IR and FT-Raman spectroscopic methods allowed to identify the cross-linking process of the aqueous composition of poly(acrylic acid)/sodium salt of carboxymethyl starch (PAA/CMS-Na) applied as a binder for moulding sands. The cross-linking was performed by chemical methods by introducing cross-linking substances with Ca(2+) ions or glutaraldehyde and by physical way, applying the microwave radiation. It was found that Ca(2+) ions cause formation of cross-linking ionic bonds within carboxyl and carboxylate groups. Glutaraldehyde generates formation of cross-linking bonds with hemiacetal and acetal structures. Whereas in the microwave radiation field, due to dehydration, lattices are formed by anhydride bonds. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Occupational allergic contact dermatitis caused by photobonded sculptured nails and a review of (meth) acrylates in nail cosmetics.

    Science.gov (United States)

    Kanerva, L; Lauerma, A; Estlander, T; Alanko, K; Henriks-Eckerman, M L; Jolanki, R

    1996-06-01

    Mono(meth)acrylates (monoacrylates and monomethacrylates) are moderate to strong sensitizers. They are used in the production of a great variety of polymers, including nail cosmetics. A patient who became occupationally sensitized to photobonded sculptured nails is reported. Detailed patch testing and analyses of the patient's nail cosmetics containing mono(meth)acrylates clarified the cause of her hand and face dermatitis. The current knowledge on mono(meth)acrylates in nail cosmetics is also reviewed. Patch testings with conventional methods, including patch testing with the patient's own substances, were performed. The patient's nail cosmetics suspected of containing mono(meth)acrylates were analyzed with gas chromatography/mass spectrometry analysis. In the (meth)acrylate series, 15 of the 31 (meth)acrylate compounds tested gave an allergic reaction: 2 acrylates, 5 methacrylates, 3 dimethacrylates, and 5 diacrylates. Epoxy diacrylates, cyanoacrylate, triacrylates, and methacrylic acid were negative. Three of seven of her own nail cosmetic preparations contained mono(meth)acrylates as revealed by the gas chromatography/mass spectrometry analysis, and these also gave allergic patch test reactions, namely, the nail liquid, nail hardener, and UV-cured nail gel. The patient probably had been sensitized to the following (meth)acrylate compounds from her nail cosmetics: tripropylene glycol diacrylate and methyl acrylate from her photobonded nail gel; ethyl methacrylate, triethylene glycol dimethacrylate, and methyl methacrylate from her nail liquid; and butyl methacrylate from her nail hardener. She was probably also sensitized to the rare sensitizer aliphatic urethane diacrylate, but the source was not verified. Because nail cosmetics containing mono(meth)acrylates are strong sensitizers, both the workers and the customers should be aware of their sensitizing capacity; they should use no-touch techniques regarding the skin before the mono(meth)acrylates are

  9. Effect of particle size, polydispersity and polymer degradation on progesterone release from PLGA microparticles: Experimental and mathematical modeling.

    Science.gov (United States)

    Busatto, Carlos; Pesoa, Juan; Helbling, Ignacio; Luna, Julio; Estenoz, Diana

    2018-01-30

    Poly(lactic-co-glycolic acid) (PLGA) microparticles containing progesterone were prepared by the solvent extraction/evaporation and microfluidic techniques. Microparticles were characterized by their size distribution, encapsulation efficiency, morphology and thermal properties. The effect of particle size, polydispersity and polymer degradation on the in vitro release of the hormone was studied. A triphasic release profile was observed for larger microparticles, while smaller microspheres showed a biphasic release profile. This behavior is related to the fact that complete drug release was achieved in a few days for smaller microparticles, during which polymer degradation effects are still negligible. A mathematical model was developed that predicts the progesterone release profiles from different-sized PLGA microspheres. The model takes into account both the dissolution and diffusion of the drug in the polymeric matrix as well as the autocatalytic effect of polymer degradation. The model was adjusted and validated with novel experimental data. Simulation results are in very good agreement with experimental results. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 40 CFR 721.2805 - Acrylate ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Acrylate ester. 721.2805 Section 721... Acrylate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an acrylate ester (PMN P-96-824) is subject to reporting under this...

  11. Isobornyl acrylate contact allergy: Rare or underdiagnosed?

    NARCIS (Netherlands)

    Christoffers, W.A.; Coenraads, P.J.; Schuttelaar, M.L.A.

    2012-01-01

    Background: Allergic contact dermatitis to isobornyl acrylate has been reported in only two cases in literature. Therefore, isobornyl acrylate is not part of a (meth) acrylates patch test series. At our department an industrial worker presented with therapy-resistant hand eczema and sensitizations

  12. The transverse strength of acrylic resin after Coleus amboinicus, Lour extract solution immersion

    Directory of Open Access Journals (Sweden)

    Devi Rianti

    2006-12-01

    Full Text Available A laboratoric experimental study was conducted on the transverse strength of acrylic resin after Coleus amboinicus, Lour extract solution immersion. The aim of this study is to know the difference of acrylic resin transverse strengths caused by immersion time variations in a concentrate solution. The study was carried out on unpolished acrylic resin plates with 65 × 10 × 2,5 mm dimension; solution with 15% Coleus amboinicus, Lour extract, and 30, 60, 90 days immersion times to measure the transverse strength and sterilized aquadest was used as control. Acrylic resin plates transverse strength was measured using Autograph AG-10 TE. The data was analyzed using One-Way Anova and LSD with 5% degree of significance. The result showed that longer immersion time will decrease the transverse strength of the acrylic resin plates. After 90 days immersion time, the transverse strength decrease is still above the recommended standard transverse strength.

  13. Manejo Microbiológico dos Grânulos de Polímero Acrílico Usados na Prevenção da Dengue/Microbiological Management of Polymer Granule Acrylic Used in the Prevention of Dengue Fever

    Directory of Open Access Journals (Sweden)

    Dante Togeiro Bastos Filgueiras

    2015-06-01

    Full Text Available Objetivos: Efetuar o manejo microbiológico dos grânulos de polímero acrílico usados na prevenção da Dengue. Materiais e Métodos: Para a determinação da presença ou ausência de coliformes totais e fecais, e de E. coli, foram realizadas avaliações utilizando metodologia do kit Colitest®. Foram elaborados cinco recipientes com mudas de planta simulando as condições naturais de vasos de polímero acrílico. Utilizaram-se cinco diferentes grânulos de polímero acrílico adquiridos comercialmente. De tais recipientes foram colhidas sete amostras em dias sucessivos. A leitura foi feita com auxílio de uma lâmpada de ondas longas de 365nm, após realizou-se prova de Indol. Resultado: Em relação ao grupo amostragem, em 11,5% não houve crescimento bacteriano, em 17,2% houve presença de E.coli e em 71,3% coliformes totais, constatando altos índices de contaminação. Discussão: Não há na literatura científica trabalhos semelhantes, porém trabalhos analisando águas de outras fontes evidenciam que a água proveniente dos vasos dos grânulos tem maior potencial de contaminação. Conclusão: Os resultados obtidos permitiram identificar altas taxas de crescimento bacteriano, evidenciando grande risco de contaminação. As informações oferecidas nos rótulos não se encontram nos padrões estabelecidos pela ANVISA. O estudo é de grande importância por efetuar controle de qualidade microbiológico visando à segurança do consumidor em um produto usado na profilaxia do dengue. Objectives: To make the microbiological management of acrylic polymer granule used in the prevention of Dengue fever. Materials and Methods: For the determination of the presence or absence of total and faecal coliform and E. coli, evaluations were performed with the use of the kit Colitest® methodology. Five vases were prepared to plant seedlings simulating the natural conditions of acrylic polymer vases. Five different acrylic polymer granule acquired

  14. PREPARATION OF BLOCK COPOLYMERS OF POLY(STYRENE) AND POLY(T-BUTYL ACRYLATE) OF VARIOUS MOLECULAR WEIGHTS AND ARCHITECTURES BY ATOM TRANSFER RADICAL POLYMERIZATION. (R826735)

    Science.gov (United States)

    Block copolymers of polystyrene and poly(t-butyl acrylate) were prepared using atom transfer radical polymerization techniques. These polymers were synthesized with a CuBr/N,N,N,NMolecularly imprinted films of acrylonitrile/methyl methacrylate/acrylic acid terpolymers: influence of methyl methacrylate in the binding performance of L-ephedrine imprinted films.

    Science.gov (United States)

    Brisbane, Carrie; McCluskey, Adam; Bowyer, Michael; Holdsworth, Clovia I

    2013-05-07

    Molecularly imprinted polymeric films (MIPFs) highly selective to 1R,2S(-)ephedrine (L-ephedrine, EPD) were produced by phase inversion post-polymerization imprinting on poly(acrylonitrile-co-methyl methacrylate-co-acrylic acid) (PAMA) terpolymers. The inclusion of methyl methacrylate (MMA) to the polymer formulation resulted in enhanced EPD selectivity which appears to be dictated by polymer composition to achieve the necessary balance between polymer rigidity and porosity. Substitution of MMA with methyl acrylate, ethyl acrylate and n-butyl acrylate resulted in a loss of EPD selectivity and EPD entrapment within the polymer matrix not observed in PAMA MIPFs. MMA, by virtue of its methyl group, is able to provide the scaffolding and rigidity necessary for stability and preservation of imprinted cavities within the PAMA MIPF leading to high EPD selectivity.

  15. Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

    Directory of Open Access Journals (Sweden)

    Jie Zhou

    2015-01-01

    Full Text Available With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP. Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt.

  16. Optimization of cellulose acrylate and grafted 4-vinylpyridine and 1-vinylimidazole synthesis

    Directory of Open Access Journals (Sweden)

    Bojanić Vaso

    2010-01-01

    Full Text Available Optimization of cellulose acrylate synthesis by reaction with sodium cellulosate and acryloyl chloride was carried out. Optimal conditions for conducting the synthesis reaction of cellulose acrylate were as follows: the molar ratio of cellulose/potassium-t-butoxide/acryloyl chloride was 1:3:10 and the optimal reaction time was 10 h. On the basis of elemental analysis with optimal conditions for conducting the reaction of cellulose acrylate, the percentage of substitution of glucose units in cellulose Y = 80.7%, and the degree of substitution of cellulose acrylate DS = 2.4 was determined. The grafting reaction of acrylate vinyl monomers onto cellulose in acetonitrile with initiator azoisobutyronitrile (AIBN in a nitrogen atmosphere was performed, by mixing for 5 h at acetonitrile boiling temperature. Radical copolymerization of synthesized cellulose acrylate and 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-2-pyrrolidinone and 9-vinylcarbazole, cellulose-poly-4-vinylpyridine (Cell-PVP, cellulose-poly-1- vinylimidazole (Cell-PVIm and cellulose-poly-1-vinyl-2-pyrrolidinone (Cell-P1V2P and cellulose-poly-9-vinylcarbazole (Cell-P9VK were synthesized. Acrylate cellulose and cellulose grafted copolymers were confirmed by IR spectroscopy, based on elementary analysis and the characteristics of grafted copolymers of cellulose were determined. The mass share of grafted copolymers, X, the relationship of derivative parts/cellulose vinyl group, Z, and the degree of grafting copolymers of cellulose (mass% were determined. In reaction of methyl iodide and cellulose-poly-4-vinylpyridine (Cell-PVP the cellulose-1-methyl-poly-4-vinylpyridine iodide (Cell-1-Me-PVPJ was synthesized. Cellulose acrylate and grafted copolymers were obtained with better thermal, electrochemical and ion-emulation properties for bonding of noble metals Au, Pt, Pd from water solutions. The synthesis optimization of cellulose acrylate was applied as a model for the synthesis of grafted

  17. Diffusion behavior of isobornyl acrylate into photopolymerized urethane acrylate films: influence of surface oxidation during curing.

    Science.gov (United States)

    Mougharbel, Ali; Mallégol, Jacky; Coqueret, Xavier

    2009-09-01

    The diffusion of liquid isobornyl acrylate (iBoA) into photopolymerized films of urethane acrylate was shown to be strongly dependent on curing conditions. Fourier transform infrared (FTIR) monitoring of iBoA sorption into films photopolymerized in oxygen-free conditions reveals that diffusion proceeds according to Fick's laws. The diffusion coefficient and the total amount of absorbed monomer are dependent on the degree of cure of the polymer network. When polymerized in air, the films exhibit an anomalous behavior, with a lag time increasing with the dose of applied radiation. At a comparable degree of cure, films photopolymerized in air showed a retarded diffusion with a characteristic diffusion constant close or equal to the Fickian diffusion coefficient observed with the film polymerized under nitrogen, suggesting that the retardation phenomenon was due to differences in surface interactions with liquid the monomer. X-ray photoelectron spectroscopy (XPS) measurements clearly revealed the occurrence of surface oxidation attributed to direct photolysis of urethane functions by the short wavelength component of the incident UV light. The lag time observed in samples polymerized in aerobic conditions is interpreted by the existence of H-bonded hydroperoxides forming a temporary barrier retarding monomer diffusion.

  18. Hydrodynamic interaction in Binary Polymer Blends measured experimentally from Ortho Positronium lifetime

    Science.gov (United States)

    Ramya, P.; Raj, J. M.; Ranganathaiah, C.

    2011-07-01

    The level of miscibility in SAN/PMMA and PS/PMMA binary blends with varying composition was characterized in terms of hydrodynamic interaction parameter (α). A new route has been found for the estimation of interface width in real polymer blend systems. Using this route, the interfacial widths in the above two binary blends have been calculated and discussed.

  19. Shrinkage Characteristics of Experimental Polymer Containing Composites under Controlled Light Curing Modes

    Directory of Open Access Journals (Sweden)

    Alain Pefferkorn

    2012-01-01

    Full Text Available The adsorption of polymethylmethacrylate polymer of different molecular weight at the aerosil/ethyleneglycol- or 1,3 butanediol-dimethacrylate interfaces was determined to provide microstructured networks. Their structural characteristics were determined to be controlled by the amount of polymer initially supplied to the system. The sediment (the settled phase characteristics, determined as a function of the polymer concentration and the rate of the polymerization shrinkage determined for composite resins, obtained by extrusion of the sediment after centrifugation, were found to be correlated. The specific role of the adsorbed polymer was found to be differently perturbed with the supplementary supply of dimethacrylate based monomer additives. Particularly, the bisphenol A dimethacrylate that generated crystals within the sediment was found to impede the shrinkage along the crystal lateral faces and strongly limit the shrinkage along its basal faces. Addition of ethyleneglycol- or polyethylene-glycoldimethacrylate monomers was determined to modify the sedimentation characteristics of the aerosil suspension and the shrinkage properties of the composites. Finally, the effects of stepwise light curing methods with prolonged lighting-off periods were investigated and found to modify the development and the final values of the composite shrinkage.

  1. Fast-Curing Epoxy and Acrylate Adhesive Development for Adverse Marine Conditions

    Science.gov (United States)

    2013-07-01

    acrylic adhesive with fast cure and a high peel strength. Chemical structure: methyl methacrylate; synthetic polymer; 3,5-diethyl- 1,2-dihydro-1...Original Weight Original Weight X 100 5 2.6 Substrate Preparation All-aluminum specimen plates were abrasive blasted using 180-grit aluminum oxide

  2. Dielectric properties of solution-grown-undoped and acrylic-acid ...

    Indian Academy of Sciences (India)

    Dielectric capacities and losses were measured, in the temperature (50–170°C) and frequency (01–100 kHz range), for undoped and acrylic acid (AA) doped ethyl cellulose (EC) films (thickness about 20 m) with progressive increase in the concentration of dopant in the polymer matrix. The variation of capacity with ...

  3. Ab initio and experimental studies of glow-discharge polymer used in laser mégajoule capsules

    Science.gov (United States)

    Colin-Lalu, P.; Recoules, V.; Salin, G.; Huser, G.

    2017-01-01

    The equations of state tables used in Inertial Confinement Fusion Capsule design tools are highly dependent on the cold curve in the multimegabar pressure range. Original ab initio molecular dynamic simulations were performed to get accurate cold curves of glow-discharge polymer (GDP) plastics. Furthermore the effect of oxygen absorption by GDP structure is studied on the cold curve, as well as its impact on the Hugoniot curves. Results are compared with the Hugoniot experimental data obtained in a recent experiment at the LULI2000 laser facility in France. This study leads to improve the equation of states knowledge of ablator materials, which is of primary importance for NIF and LMJ experiments.

  4. Theoretical and experimental investigation of drug-polymer interaction and miscibility and its impact on drug supersaturation in aqueous medium.

    Science.gov (United States)

    Baghel, Shrawan; Cathcart, Helen; O'Reilly, Niall J

    2016-10-01

    Amorphous solid dispersions (ASDs) have the potential to offer higher apparent solubility and bioavailability of BCS class II drugs. Knowledge of the solid state drug-polymer solubility/miscibility and their mutual interaction are fundamental requirements for the effective design and development of such systems. To this end, we have carried out a comprehensive investigation of various ASD systems of dipyridamole and cinnarizine in polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) at different drug loadings. Theoretical and experimental examinations (by implementing binary and ternary Flory-Huggins (F-H) theory) related to drug-polymer interaction/miscibility including solubility parameter approach, melting point depression method, phase diagram, drug-polymer interaction in the presence of moisture and the effect of drug loading on interaction parameter were performed. The information obtained from this study was used to predict the stability of ASDs at different drug loadings and under different thermal and moisture conditions. Thermal and moisture sorption analysis not only provided the composition-dependent interaction parameter but also predicted the composition dependent miscibility. DPM-PVP, DPM-PAA and CNZ-PAA systems have shown molecular level mixing over the complete range of drug loading. For CNZ-PVP, the presence of a single Tg at lower drug loadings (10, 20 and 35%w/w) indicates the formation of solid solution. However, drug recrystallization was observed for samples with higher drug weight fractions (50 and 65%w/w). Finally, the role of polymer in maintaining drug supersaturation has also been explored. It has been found that drug-polymer combinations capable of hydrogen-bonding in the solution state (DPM-PVP, DPM-PAA and CNZ-PAA) are more effective in preventing drug crystallization compared to the drug-polymer systems without such interaction (CNZ-PVP). The DPM-PAA system outperformed all other ASDs in various stability conditions (dry-state, in

  5. Solvent effects on acrylate kp in organic media?-A systematic PLP-SEC study.

    Science.gov (United States)

    Haehnel, Alexander P; Wenn, Benjamin; Kockler, Katrin; Bantle, Tobias; Misske, Andrea M; Fleischhaker, Friederike; Junkers, Thomas; Barner-Kowollik, Christopher

    2014-12-01

    The Arrhenius parameters of the propagation rate coefficient, kp , are determined employing high-frequency pulsed laser polymerization-size exclusion chromatography (PLP-SEC) for the homologous series of five linear alkyl acrylates (i.e., methyl acrylate (MA), butyl acrylate (BA), dodecyl acrylate (DA), stearyl acrylate (SA), and behenyl acrylate (BeA)) in 1 m solution in butyl acetate (BuAc) as well as in toluene. The comparison of the obtained kp values with the literature known values for bulk demonstrates that no significant solvent influence neither in BuAc nor in toluene on the propagation reaction compared to bulk is detectable. Concomitantly, the kp values in toluene and in BuAc solution display a similar increase with increasing number of C-atoms in the ester side chain as was previously reported for the bulk systems. These findings are in clear contrast to earlier studies, which report a decrease of kp with increasing ester side chain length in toluene. The additional investigation of the longest and shortest ester side chain acrylate (i.e., BeA and MA) over the entire experimentally available concentration range at one temperature (i.e., 50 °C) does not reveal any general concentration dependence and all observed differences in the kp are within the experimental error. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Real-time monitoring of the penetration of amphiphilic acrylate copolymer in leather using a fluorescent copolymer as tracer.

    Science.gov (United States)

    Du, Jin-Xia; Shi, Lu; Peng, Bi-Yu

    2015-12-01

    A fluorescent tracer, poly (acrylic-co-stearyl acrylate-co-3-acryloyl fluorescein) [poly (AA-co-SA-co-Ac-Flu)], used for real-time monitoring the penetration of amphiphilic acrylate copolymer, poly (acrylic-co-stearyl acrylate) [poly (AA-co-SA)], in leather was synthesized by radical polymerization of acrylic, stearyl acrylate and fluorescent monomer, 3-acryloyl fluorescein (Ac-Flu). The structure, molecular weight, introduced fluorescent group content and fluorescent characteristics of the fluorescent tracer and target copolymer, amphiphilic acrylate copolymer, were also characterized. The results show that the tracer presents the similar structural characteristics to the target and enough fluorescence intensity with 1.68 wt % of the fluorescent monomer introduced amount. The vertical section of the leather treated with the target copolymer mixing with 7% of the tracer exhibits evident fluorescence, and the change of fluorescence intensity along with the vertical section with treating time increasing can reflect the penetration depth of the target copolymer. The introduction of the fluorescent group in polymer structure through copolymerization with a limited amount of fluorescent monomer, Ac-Flu, is an effective way to make a tracer to monitor the penetration of the target in leather, which provides a new thought for the penetration research of syntans such as vinyl copolymer materials in leather manufacture. © 2015 Wiley Periodicals, Inc.

  7. Two decades of occupational (meth)acrylate patch test results and focus on isobornyl acrylate.

    Science.gov (United States)

    Christoffers, Wietske A; Coenraads, Pieter-Jan; Schuttelaar, Marie-Louise A

    2013-08-01

    Acrylates constitute an important cause of occupational contact dermatitis. Isobornyl acrylate sensitization has been reported in only 2 cases. We encountered an industrial process operator with occupational contact dermatitis caused by isobornyl acrylate. (i) To investigate whether it is relevant to add isobornyl acrylate to the (meth)acrylate test series. (ii) To report patients with (meth)acrylate contact allergy at an occupational dermatology clinic. Our patch test database was screened for positive reactions to (meth)acrylates between 1993 and 2012. A selected group of 14 patients was tested with an isobornyl acrylate dilution series: 0.3%, 0.1%, 0.033%, and 0.01%. Readings were performed on D2, D3, and D7. One hundred and fifty-one patients were tested with our (meth)acrylate series; 24 had positive reactions. Most positive reactions were to 2-hydroxypropyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, and diethyleneglycol diacrylate. Hypothetical screening with 2-hydroxypropyl acrylate, ethyleneglycol dimethacrylate, ethoxylated bisphenol A glycol dimethacrylate and trimethylolpropane triacrylate identified 91.7% of the 24 patients. No positive reactions were observed in 14 acrylate-positive patients tested with the isobornyl acrylate dilution series. The 0.3% isobornyl acrylate concentration induced irritant reactions in 3 patients. We report a rare case of allergic contact dermatitis caused by isobornyl acrylate. However, this study provides insufficient support for isobornyl acrylate to be added to a (meth)acrylate series. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Modélisation du Comportement Thermomécanique des Polymères à mémoire de Forme

    OpenAIRE

    Arrieta escobar, Juan Sebastian

    2014-01-01

    A chemically crosslinked amorphous acrylate network has been prepared in the laboratory. Its mechanical properties were characterized by quasi-static and cyclic uniaxial tensile tests, while varying the temperature. The shape memory property of the polymer was recognized by the application of specific thermomechanical cycles in uniaxial tension (free-length and constrained-length recovery). During the experimental study, the thermomechanical cycle parameters were varied in order to study thei...

  9. Optically transparent super-hydrophobic thin film fabricated by reusable polyurethane-acrylate (PUA) mold

    Science.gov (United States)

    Park, J.-S.; Park, J.-H.; Lee, D.-W.

    2018-02-01

    In this paper, we describe a simple manufacturing method for producing an optically transparent super-hydrophobic polymer thin film using a reusable photo-curable polymer mold. Soluble photoresist (PR) molds were prepared with under-exposed and under-baked processes, which created unique hierarchical micro/nano structures. The reverse phase of the PR mold was replicated on the surface of polydimethylsiloxane (PDMS) substrates. The unique patterns on the replicated PDMS molds were successfully transferred back to the UV curable polyurethane-acrylate (PUA) using a laboratory-made UV exposure system. Continuous production of the super-hydrophobic PDMS thin film was demonstrated using the reusable PUA mold. In addition, hydrophobic nano-silica powder was sprayed onto the micro/nano structured PDMS surfaces to further improve hydrophobicity. The fabricated PDMS thin films with hierarchical surface texturing showed a water contact angle  ⩾150°. Excellent optical transmittance within the range of visible light of wavelengths between 400–800 nm was experimentally confirmed using a spectrophotometer. High efficiency of the super-hydrophobic PDMS film in optical transparency was also confirmed using solar panels. The fabricated PUA molds are very suitable for use in roll-to-roll or roll-to-plate systems which allow continuous production of super-hydrophobic thin films with an excellent optical transparency.

  10. Experimental investigation on the effects of recycled aggregate on fracture behavior of polymer concrete

    Directory of Open Access Journals (Sweden)

    João Marciano Laredo dos Reis

    2011-09-01

    Full Text Available The sustainable management of solid wastes stimulates metallurgic and metal mechanics industries to look for safety applications for these wastes. The present paper examines the fracture behavior of polymer concrete (PC manufactured with recycled foundry waste in substitution of fresh one. The recycled foundry sand is contaminated with polymer resin from the mold making process. Epoxy and unsaturated polyester resins were used as binder as cement substitute. The fracture results are analyzed by fracture energy; Gf, fracture toughness, K Ic, and the crack tip opening displacement, CTOD. It is found that the use of recycled foundry sand significantly influences the fracture properties. The use of recycled sand increase fracture toughness and similar fracture energy is observed. These results show that recycled sand is an excellent alternative as raw material.

  11. Experimental Investigation on the Durability of Glass Fiber-Reinforced Polymer Composites Containing Nanocomposite

    Directory of Open Access Journals (Sweden)

    Weiwen Li

    2013-01-01

    Full Text Available Nanoclay layers incorporated into polymer/clay nanocomposites can inhibit the harmful penetration of water and chemicals into the material, and thus the durability of glass fiber-reinforced polymer (GFRP composites should be enhanced by using polymer/clay nanocomposite as the matrix material. In this study, 1.5 wt% vinyl ester (VE/organoclay and 2 wt% epoxy (EP/organoclay nanocomposites were prepared by an in situ polymerization method. The dispersion states of clay in the nanocomposites were studied by performing XRD analysis. GFRP composites were then fabricated with the prepared 1.5 wt% VE/clay and 2.0 wt% EP/clay nanocomposites to investigate the effects of a nanocomposite matrix on the durability of GFRP composites. The durability of the two kinds of GFRP composites was characterized by monitoring tensile properties following degradation of GFRP specimens aged in water and alkaline solution at 60°C, and SEM was employed to study fracture behaviors of aged GFRP composites under tension. The results show that tensile properties of the two types of GFRP composites with and without clay degrade significantly with aging time. However, the GFRP composites with nanoclay show a lower degradation rate compared with those without nanoclay, supporting the aforementioned hypothesis. And the modification of EP/GFRP enhanced the durability more effectively.

  12. Control and Experimental Characterization of a Methanol Reformer for a 350 W High Temperature Polymer Electrolyte Membrane Fuel Cell system

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen; Jensen, Hans-Christian Becker

    This work involves the an experimental characterisation and the development of control strategies for the methanol reformer system used in the Serenergy Serenus H3 E-350 high temperature polymer electrolyte membrane (HTPEM) fuel cell system. The system consists of a fuel evaporator utilizing...... the high temperature waste gas from a cathode air cooled 45 cell HTPEM fuel cell stack. The MEAs used are BASF P2100 which use phosphoric acid doped polybenzimidazole type membranes; an MEA with high CO tolerance and no complex humidity requirements. The methanol reformer used is integrated into a compact...... unit that allows the use of waste heat from the fuel cell stack in the reformer system, and a burner unit is also integrated to supplement provide heat using the stack anode hydrogen. The reformer is initially placed in an experimental system capable of emulating the interfaces to the fuel cell system...

  13. Synthesis of Fluorinated Polymers and Evaluation of Wettability

    Directory of Open Access Journals (Sweden)

    Tamami Kimura

    2016-03-01

    Full Text Available Two kinds of fluorinated polymers were synthesized: an acrylate polymer having a fluorinated triethylene glycol as a pendant group (2a and a fluoroalkyl acrylate polymer (2b. The contact angle of these fluorinated polymers against water, non-fluorinated alcohols and fluorinated alcohols were evaluated. As compared with the fluoroalkyl polymer (2b, fluoroethylene glycol polymer (2a showed smaller contact angle against water and non-fluorinated alcohols. This supports the proposition that changing the alkyl chain into the ethylene glycol-type chain gave some interaction between etheric oxygen and water or non-fluorinated alcohols. In addition, fluoroalkyl acrylate polymer (2b showed remarkably low values of critical surface tension.

  14. IN VITRO ANTIFUNGAL ACTION OF DIFFERENT SUBSTANCES OVER MICROWAVED-CURED ACRYLIC RESINS

    OpenAIRE

    Montagner, Henrique; Montagner, Francisco; Braun, Katia Olmedo; Peres, Paulo Edelvar Correa; Gomes, Brenda Paula Figueiredo de Almeida

    2009-01-01

    OBJECTIVE: The presence of Candida albicans on the surfaces of denture-base acrylic resins is strongly related to the development of oral stomatitis. This study evaluated the antifungal action of different agents over microwave-cured acrylic resin without polishing specimens previously contaminated with Candida albicans. MATERIAL AND METHODS: Sixty specimens were immersed in BHI broth previously inoculated with the yeast and stored for 3 h at 37ºC. They were divided into 5 experimental groups...

  15. The fabrication of wavelength shifting lightguides from clear acrylic sheet by disperse dyeing

    Science.gov (United States)

    McMillan, J. E.

    2015-06-01

    Wavelength shifting lightguides have found extensive use as a means of collecting scintillation or cherenkov light from large areas onto a smaller area photodetector and for matching the emitted spectrum to the spectral response of the photodetector. Conventionally, such lightguides are fabricated by casting acrylic polymer with the fluorescent dye incorporated in the bulk. A technique has been developed in which plain cast acrylic sheet is disperse dyed in an aqueous bath. The resulting lightguide has the fluorescent dye held in a thin layer at the surface of the material. A number of different fluorescent dyes are demonstrated

  16. An ORMOSIL-Containing Orthodontic Acrylic Resin with Concomitant Improvements in Antimicrobial and Fracture Toughness Properties

    Science.gov (United States)

    Rueggeberg, Frederick A.; Niu, Li-na; Mettenberg, Donald; Yiu, Cynthia K. Y.; Blizzard, John D.; Wu, Christine D.; Mao, Jing; Drisko, Connie L.; Pashley, David H.; Tay, Franklin R.

    2012-01-01

    Global increase in patients seeking orthodontic treatment creates a demand for the use of acrylic resins in removable appliances and retainers. Orthodontic removable appliance wearers have a higher risk of oral infections that are caused by the formation of bacterial and fungal biofilms on the appliance surface. Here, we present the synthetic route for an antibacterial and antifungal organically-modified silicate (ORMOSIL) that has multiple methacryloloxy functionalities attached to a siloxane backbone (quaternary ammonium methacryloxy silicate, or QAMS). By dissolving the water-insoluble, rubbery ORMOSIL in methyl methacrylate, QAMS may be copolymerized with polymethyl methacrylate, and covalently incorporated in the pressure-processed acrylic resin. The latter demonstrated a predominantly contact-killing effect on Streptococcus mutans ATCC 36558 and Actinomyces naselundii ATCC 12104 biofilms, while inhibiting adhesion of Candida albicans ATCC 90028 on the acrylic surface. Apart from its favorable antimicrobial activities, QAMS-containing acrylic resins exhibited decreased water wettability and improved toughness, without adversely affecting the flexural strength and modulus, water sorption and solubility, when compared with QAMS-free acrylic resin. The covalently bound, antimicrobial orthodontic acrylic resin with improved toughness represents advancement over other experimental antimicrobial acrylic resin formulations, in its potential to simultaneously prevent oral infections during appliance wear, and improve the fracture resistance of those appliances. PMID:22870322

  17. An ORMOSIL-containing orthodontic acrylic resin with concomitant improvements in antimicrobial and fracture toughness properties.

    Directory of Open Access Journals (Sweden)

    Shi-qiang Gong

    Full Text Available Global increase in patients seeking orthodontic treatment creates a demand for the use of acrylic resins in removable appliances and retainers. Orthodontic removable appliance wearers have a higher risk of oral infections that are caused by the formation of bacterial and fungal biofilms on the appliance surface. Here, we present the synthetic route for an antibacterial and antifungal organically-modified silicate (ORMOSIL that has multiple methacryloloxy functionalities attached to a siloxane backbone (quaternary ammonium methacryloxy silicate, or QAMS. By dissolving the water-insoluble, rubbery ORMOSIL in methyl methacrylate, QAMS may be copolymerized with polymethyl methacrylate, and covalently incorporated in the pressure-processed acrylic resin. The latter demonstrated a predominantly contact-killing effect on Streptococcus mutans ATCC 36558 and Actinomyces naselundii ATCC 12104 biofilms, while inhibiting adhesion of Candida albicans ATCC 90028 on the acrylic surface. Apart from its favorable antimicrobial activities, QAMS-containing acrylic resins exhibited decreased water wettability and improved toughness, without adversely affecting the flexural strength and modulus, water sorption and solubility, when compared with QAMS-free acrylic resin. The covalently bound, antimicrobial orthodontic acrylic resin with improved toughness represents advancement over other experimental antimicrobial acrylic resin formulations, in its potential to simultaneously prevent oral infections during appliance wear, and improve the fracture resistance of those appliances.

  18. METHACRYLATE AND ACRYLATE ALLERGY IN DENTAL STUDENTS.

    OpenAIRE

    Maya Lyapina; Assya Krasteva; Maria Dencheva; Mariana Tzekova; Angelina Kisselova-Yaneva

    2013-01-01

    A multitude of acrylic monomers is used in dentistry, and when dental personnel, patients or students of dental medicine become sensitized, it is of great importance to identify the dental ;acrylic preparations to which the sensitized individual can be exposed. Numerous studies confirm high incidence of sensitization to (meth) acrylates in dentatal professionals, as well as in patients undergoing dental treatment and exposed to resin-based materials. Quite a few studies are available aiming t...

  19. Vinyl Acetate/butyl acrylate/acrylate Research of Ternary Soap-free Emulsion Polymerization

    Directory of Open Access Journals (Sweden)

    Xiao Li-guang

    2016-01-01

    Full Text Available Through the vinyl acetate/butyl acrylate/acrylic acrylic emulsion preparation without soap vinegar, with solid content, gel, emulsion stability and film forming properties and tensile strength as the main index to study the effect of raw materials on the properties of emulsion. Through the infrared spectrometer soap-free emulsion for microscopic analysis research. Study of the ternary soap-free vinegar acrylic emulsion with good performance.

  20. Effect of Antiadherents on the Physical and Drug Release Properties of Acrylic Polymeric Films.

    Science.gov (United States)

    Ammar, Hussein O; Ghorab, Mamdouh M; Felton, Linda A; Gad, Shadeed; Fouly, Aya A

    2016-06-01

    Antiadherents are used to decrease tackiness of a polymer coating during both processing and subsequent storage. Despite being a common excipient in coating formulae, antiadherents may affect mechanical properties of the coating film as well as drug release from film-coated tablets, but how could addition of antiadherents affect these properties and to what extent and is there a relation between the physical characteristics of the tablet coat and the drug release mechanisms? The aim of this study was to evaluate physical characteristics of films containing different amounts of the antiadherents talc, glyceryl monostearate, and PlasACRYL(TM) T20. Eudragit RL30D and Eudragit RS30D as sustained release polymers and Eudragit FS30D as a delayed release material were used. Polymer films were characterized by tensile testing, differential scanning calorimetry (DSC), microscopic examination, and water content as calculated from loss on drying. The effect of antiadherents on in vitro drug release for the model acetylsalicylic acid tablets coated with Eudragit FS30D was also determined. Increasing talc concentration was found to decrease the ability of the polymer films to resist mechanical stress. In contrast, glyceryl monostearate (GMS) and PlasACRYL produced more elastic films. Talc at concentrations higher than 25% caused negative effects, which make 25% concentration recommended to be used with acrylic polymers. All antiadherents delayed the drug release at all coating levels; hence, different tailoring of drug release may be achieved by adjusting antiadherent concentration with coating level.

  1. Numerical and experimental study of radiation induced conductivity change of carbon nanotube filled polymers

    Science.gov (United States)

    Liu, Fangjun; Sun, Yonghai; Sun, Weijie; Sun, Zhendong; Yeow, John T. W.

    2017-06-01

    Measuring the conductivity changes of sensing materials to detect a wide range of radiation energy and dosage is one of the major sensing mechanisms of radiation sensors. Carbon nanotube (CNT) filled composites are suitable for sensing radiation because of the extraordinary electrical properties of CNTs and the CNT-network formed inside the polymer matrix. Although the use of CNT-based nanocomposites as potential radiation sensing materials has been widely studied, there is still a lack of theoretical models to analyze the relationship between electrical conductivity and radiation dosages. In this article, we propose a 3D model to describe the electrical conductivity of CNT-based nanocomposites when being irradiated by ionizing radiation. The Monte Carlo method has been employed to calculate radiation intensity, CNT concentration and alignment’s influence on the electrical conductivity. Our simulation shows a better agreement when CNT loading is between the percolation threshold and 3% volume fraction. Radiation experiments have been performed to verify the reliability of our model to illustrate a power function relationship between the electrical conductivity of a CNT-filled polymer and radiation intensity. In addition, the predicted alignment to obtain the best sensitivity for radiation sensing has been discussed to help with CNT-network building in the fabrication process.

  2. Use of a continuous-flow microreactor for thiol-ene functionalization of RAFT-derived poly(butyl acrylate)

    OpenAIRE

    Vandenbergh, Joke; Junkers, Thomas

    2012-01-01

    This study describes the synthesis of functionalized RAFT-derived poly(n-butyl acrylate) polymers via the use of a continuous-flow microreactor, in which aminolysis as well as thiol-ene reactions are executed in reaction times of just 20 minutes. Poly(n-butyl acrylate) (M-n = 3800 g mol(-1), PDI = 1.10) with a trithiocarbonate end group was prepared via a conventional RAFT process. The polymer was then functionalized via aminolysis/thiol-ene reactions in the micro-flow reactor with isobornyl ...

  3. Filtration of triazine herbicides by polymer-clay sorbents: coupling an experimental mechanistic approach with empirical modeling.

    Science.gov (United States)

    Gardi, Ido; Nir, Shlomo; Mishael, Yael G

    2015-03-01

    Triazine herbicides detected in surface and groundwater pose environmental and health risks. Removal of triazine herbicides (simazine, atrazine and terbuthylazine) by polymer-clay composites was studied and modeled. Their binding by a poly 4-vinyl pyridine co styrene-montmorillonite (HPVP-CoS-MMT) composite was especially high due to specific interactions between the herbicides and polymer, mainly hydrogen bonds and π-π stacking. The binding kinetics to the composite was in the order of simazine > atrazine > terbuthylazine, which was in accord with their equilibrium Langmuir binding coefficients; 44,000, 17,500 and 16,500 M(-1), respectively, which correlated with herbicide accessibility to form specific interaction with the polymer. Simazine binding kinetics to the composite was significantly faster than to granulated activated carbon (GAC), reaching 93% vs 38% of the maximal adsorption within 10 min, respectively. Herbicide filtration by composite columns was adequately fitted by a model which considers convection and employs Langmuir formalism for kinetics of adsorption/desorption. Filtration of simazine (10 μg L(-1)) by composite columns (40 cm long, which included 26 g composite mixed with sand 1:40 (weight ratio)), was well predicted by the model with nearly 120 L purified, i.e., effluent concentrations were below regulation limit (3 μg L(-1)). Effluent concentrations from GAC columns exceeded the limit after filtering 5 L. Experimental results and model predictions suggest that while GAC has a high capacity for simazine binding, the composite has higher affinity towards the herbicide and its adsorption is faster, which yields more efficient filtration by composite columns. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Contact dermatitis from acrylics in a histology laboratory assistant.

    Science.gov (United States)

    Molina, Luciana; Amado, Antoine; Mattei, Peter L; Taylor, James S

    2009-01-01

    The use of acrylics has expanded enormously, resulting in a vast range of products for both occupational and non-occupational purposes. Acrylics reported to cause allergic contact dermatitis in histology technicians are 2-hydroxyethyl methacrylate and 2-hydroxyethel acrylate.

  5. Synthesis and Characterization of Waterborne Fluoropolymers Prepared by the One-Step Semi-Continuous Emulsion Polymerization of Chlorotrifluoroethylene, Vinyl Acetate, Butyl Acrylate, Veova 10 and Acrylic Acid

    Directory of Open Access Journals (Sweden)

    Hongzhu Liu

    2017-01-01

    Full Text Available Waterborne fluoropolymer emulsions were synthesized using the one-step semi-continuous seed emulsion polymerization of chlorotrifluoroethylene (CTFE, vinyl acetate (VAc, n-butyl acrylate (BA, Veova 10, and acrylic acid (AA. The main physical parameters of the polymer emulsions were tested and analyzed. Characteristics of the polymer films such as thermal stability, glass transition temperature, film-forming properties, and IR spectrum were studied. Meanwhile, the weatherability of fluoride coatings formulated by the waterborne fluoropolymer and other coatings were evaluated by the quick ultraviolet (QUV accelerated weathering test, and the results showed that the fluoropolymer with more than 12% fluoride content possessed outstanding weather resistance. Moreover, scale-up and industrial-scale experiments of waterborne fluoropolymer emulsions were also performed and investigated.

  6. Synthesis and Characterization of Waterborne Fluoropolymers Prepared by the One-Step Semi-Continuous Emulsion Polymerization of Chlorotrifluoroethylene, Vinyl Acetate, Butyl Acrylate, Veova 10 and Acrylic Acid.

    Science.gov (United States)

    Liu, Hongzhu; Bian, Jiming; Wang, Zhonggang; Hou, Chuan-Jin

    2017-01-22

    Waterborne fluoropolymer emulsions were synthesized using the one-step semi-continuous seed emulsion polymerization of chlorotrifluoroethylene (CTFE), vinyl acetate (VAc), n-butyl acrylate (BA), Veova 10, and acrylic acid (AA). The main physical parameters of the polymer emulsions were tested and analyzed. Characteristics of the polymer films such as thermal stability, glass transition temperature, film-forming properties, and IR spectrum were studied. Meanwhile, the weatherability of fluoride coatings formulated by the waterborne fluoropolymer and other coatings were evaluated by the quick ultraviolet (QUV) accelerated weathering test, and the results showed that the fluoropolymer with more than 12% fluoride content possessed outstanding weather resistance. Moreover, scale-up and industrial-scale experiments of waterborne fluoropolymer emulsions were also performed and investigated.

  7. Nanomolar concentration of blood-soluble drag-reducing polymer inhibits experimental metastasis of human breast cancer cells

    Directory of Open Access Journals (Sweden)

    Ding Z

    2017-02-01

    Full Text Available Zhijie Ding,1,* Marion Joy,1,* Marina V Kameneva,1-3 Partha Roy1,3-6 1Department of Bioengineering, 2Department of Surgery, 3McGowan Institute of Regenerative Medicine, 4Department of Pathology, 5Department of Cell Biology, 6Magee Women’s Research Institute, University of Pittsburgh, Pittsburgh, PA, USA *These authors contributed equally to this work Abstract: Metastasis is the leading cause of cancer mortality. Extravasation of cancer cells is a critical step of metastasis. We report a novel proof-of-concept study that investigated whether non-toxic blood-soluble chemical agents capable of rheological modification of the near-vessel-wall blood flow can reduce extravasation of tumor cells and subsequent development of metastasis. Using an experimental metastasis model, we demonstrated that systemic administration of nanomolar concentrations of so-called drag-reducing polymer dramatically impeded extravasation and development of pulmonary metastasis of breast cancer cells in mice. This is the first proof-of-principle study to directly demonstrate physical/rheological, as opposed to chemical, way to prevent cancer cells from extravasation and developing metastasis and, thus, it opens the possibility of a new direction of adjuvant interventional approach in cancer. Keywords: breast cancer, metastasis, extravasation, hemodynamics, drag-reducing polymer, blood cell traffic, microvessels

  8. Inactivation of pulmonary surfactant due to serum-inhibited adsorption and reversal by hydrophilic polymers: experimental

    DEFF Research Database (Denmark)

    Taeusch, H William; de la Serna, Jorge Bernardino; Perez-Gil, Jesus

    2005-01-01

    increases in pi did not occur when surfactants were applied to subphases containing serum. Components of serum are surface active and adsorb reversibly to the interface increasing pi up to a concentration-dependent saturation value, pi(max). When surfactants were applied to subphases containing serum......The rate of change of surface pressure, pi, in a Langmuir trough following the deposition of surfactant suspensions on subphases containing serum, with or without polymers, is used to model a likely cause of surfactant inactivation in vivo: inhibition of surfactant adsorption due to competitive...... adsorption of surface active serum proteins. Aqueous suspensions of native porcine surfactant, organic extracts of native surfactant, and the clinical surfactants Curosurf, Infasurf, and Survanta spread on buffered subphases increase the surface pressure, pi, to approximately 40 mN/m within 2 min...

  9. In Plan Shear Retrofit of Masonry Walls with Fibre Reinforced Polymer Composites Experimental Investigations

    Directory of Open Access Journals (Sweden)

    Tamás Nagy-György

    2006-01-01

    Full Text Available The paper presents the results from tests on clay brick masonry walls strengthened using fiber reinforced polymer (FRP composites. Five 1.50x1.50 m wall specimens have been subjected to pure in plan shear loads up to failure and then retrofitted on one side, with different types, percentages and lay-ups of the fiber sheets. Based on the experi¬mental results, it was proven the effectiveness of using externally bonded composites for retrofitting brick masonry walls, with less disruption during strengthening, and in this way with reduced costs compared with other conventional repairing and strengthening tech¬niques. Performances of the different strengthening configurations were compared in terms of ultimate load, strain in composite and failure mechanism.

  10. Flexural Strength of Cold and Heat Cure Acrylic Resins Reinforced with Different Materials

    Directory of Open Access Journals (Sweden)

    Bijan Heidari

    2015-10-01

    Full Text Available Objectives: Heat-polymerized acrylic resin has been the most commonly used denture base material for over 60 years. However, the mechanical strength of acrylic resin is not adequate for long-term clinical performance of dentures. Consequently, fracture is a com- mon clinical occurrence, which often occurs in the midline of denture base.This study aimed to evaluate the efficacy of cold cure and heat cure acrylic resins, rein- forced with glass fibers, polyethylene fibers, and metal wire for denture base repair.Materials and Methods: Ninety specimens were prepared and allocated to nine groups. Ten specimens were included in the control group, and 80 were allocated to 8 experi- mental groups. In the experimental groups, the specimens were sectioned into two halves from the middle, and were then divided into two main groups: one group was repaired with heat cure acrylic resin, and the other with cold cure acrylic resin. Each group was di- vided into 4 subgroups: unreinforced, reinforced with glass fibers, polyethylene fibers, and metal wire. All specimens were then subjected to a 3-point bending test, and the flexural strength was calculated.Results: The group repaired with heat cure acrylic resin and reinforced with glass fiber showed the highest flexural strength; however, the group repaired with cold cure acrylic resin and reinforced with polyethylene fibers had the lowest flexural strength. There was no significant difference between the groups repaired with heat cure and cold cure acrylic resins without reinforcement.Conclusion: Repairing denture base with heat cure acrylic resin, reinforced with glass fi- bers increases the flexural strength of denture base.

  11. The Effect of Hydrogen Bonding on Radical Semi-Batch Copolymerization of Butyl Acrylate and 2-Hydroxyethyl Acrylate

    National Research Council Canada - National Science Library

    Jan E S Schier; David Cohen-Sacal; Owen R Larsen; Robin A Hutchinson

    2017-01-01

    The radical copolymerization of butyl acrylate (BA) and 2-hydroxyethyl acrylate (HEA) was investigated under batch and semi-batch operations, with a focus on the influence of hydrogen-bonding on acrylate backbiting...

  12. Radiation Induced Grafting of Acrylate onto Waste Rubber: The Effect of Monomer Type

    Directory of Open Access Journals (Sweden)

    Shirajuddin Siti Salwa M.

    2017-01-01

    Full Text Available The effect of three different acrylate group monomers, namely n-butyl acrylate, methacrylic acid and tripropylene glycol diacrylate of radiation induced grafting onto waste rubber was studied. The electron beam accelerator operated at voltage of 2MeV was used to irradiate the waste rubber at 10 kGy and 100 kGy absorbed radiation dose, respectively. The formation of grafting was observed from the increase in the grafting yield and confirmed by Transformed Infra-Red Spectroscopy results. According to the result obtained, only tripropylene glycol diacrylate was selected to graft onto waste rubber. The carbonyl bond from acrylate groups was seen at 1726 cm-1 band which confirmed the presence of TPGDA in the polymer matrix. This indicates the successful preparation of the TPGDA-grafted waste rubber via radiation induced grafting techniques.

  13. Spatial Frequency Responses of Anisotropic Refractive Index Gratings Formed in Holographic Polymer Dispersed Liquid Crystals

    Directory of Open Access Journals (Sweden)

    Yoshiaki Fukuda

    2016-03-01

    Full Text Available We report on an experimental investigation of spatial frequency responses of anisotropic transmission refractive index gratings formed in holographic polymer dispersed liquid crystals (HPDLCs. We studied two different types of HPDLC materials employing two different monomer systems: one with acrylate monomer capable of radical mediated chain-growth polymerizations and the other with thiol-ene monomer capable of step-growth polymerizations. It was found that the photopolymerization kinetics of the two HPDLC materials could be well explained by the autocatalytic model. We also measured grating-spacing dependences of anisotropic refractive index gratings at a recording wavelength of 532 nm. It was found that the HPDLC material with the thiol-ene monomer gave higher spatial frequency responses than that with the acrylate monomer. Statistical thermodynamic simulation suggested that such a spatial frequency dependence was attributed primarily to a difference in the size of formed liquid crystal droplets due to different photopolymerization mechanisms.

  14. Additive manufacturing of short and mixed fibre-reinforced polymer

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, James; Duoss, Eric B.; Rodriguez, Jennifer Nicole; Worsley, Marcus A.; King, Michael J.

    2018-01-09

    Additive manufacturing of a fiber-reinforced polymer (FRP) product using an additive manufacturing print head; a reservoir in the additive manufacturing print head; short carbon fibers in the reservoir, wherein the short carbon fibers are randomly aligned in the reservoir; an acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin in the reservoir, wherein the short carbon fibers are dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; a tapered nozzle in the additive manufacturing print head operatively connected to the reservoir, the tapered nozzle produces an extruded material that forms the fiber-reinforced polymer product; baffles in the tapered nozzle that receive the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; and a system for driving the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin from the reservoir through the tapered nozzle wherein the randomly aligned short carbon fibers in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin are aligned by the baffles and wherein the extruded material has the short carbon fibers aligned in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin that forms the fiber-reinforced polymer product.

  15. In vitro cytotoxicity of self-curing acrylic resins of different colors.

    Science.gov (United States)

    Retamoso, Luciana Borges; da Cunha, Taís de Morais Alves; Pithon, Matheus Melo; dos Santos, Rogério Lacerda; Martins, Fernanda Otaviano; Romanos, Maria Teresa Villela; Tanaka, Orlando Motohiro

    2014-01-01

    The aim of this study was to assess the in vitro cytotoxicity of acrylic resins of different colors over time. Specimens were divided into 4 groups (n = 6) according to the color of the acrylic resin (Orto Class, Clássico, Campinas, São Paulo, Brazil): Group 1, clear acrylic resin; Group 2, pink acrylic resin; Group 3, blue acrylic resin; and Group 4, green acrylic resin. All specimens were fabricated according to the mass manipulation technique and submitted to mechanical polishing protocol. The control was performed with an amalgam specimen (C+), a glass specimen (C-) and cell control (CC). Specimens were immersed in Minimum Eagle's Medium (MEM) and incubated for 24 h at 37ºC. The extracts from the experimental material were filtered and mixed with L929 fibroblast. Cytotoxicity was evaluated at four different times, 24, 48, 72 and 168 h. After contact, cells were incubated for 24 h and added to 100 µ of 0.01% neutral red dye. The cells were incubated for 3 h for pigment incorporation and fixed. Cells viability was determined by a spectroscopic (BioTek, Winooski, Vermont, USA) with a 492-nm wavelength λ=492 nm). There were no statistical differences between the experimental groups and the CC and C- groups. Clear, pink, blue and green self-curing acrylic resins fabricated by means of the mass manipulation technique and mechanically polished are not cytotoxic. Neither the pigment added to the self-curing acrylic resin nor the factor of time influenced the cytotoxicity of the material.

  16. In vitro cytotoxicity of self-curing acrylic resins of different colors

    Directory of Open Access Journals (Sweden)

    Luciana Borges Retamoso

    2014-08-01

    Full Text Available OBJECTIVE: The aim of this study was to assess the in vitro cytotoxicity of acrylic resins of different colors over time. METHODS: Specimens were divided into 4 groups (n = 6 according to the color of the acrylic resin (Orto Class, Clássico, Campinas, São Paulo, Brazil: Group 1: clear acrylic resin; group 2: pink acrylic resin; group 3: blue acrylic resin and group 4: green acrylic resin. All specimens were fabricated according to the mass manipulation technique and submitted to mechanical polishing protocol. The control was performed with an amalgam specimen (C+, a glass specimen (C- and cell control (CC. Specimens were immersed in Minimum Eagle's Medium (MEM and incubated for 24 h at 37o C. The extracts from the experimental material were filtered and mixed with L929 fibroblast. Cytotoxicity was evaluated at 4 different times, 24, 48, 72 and 168 h. After contact, cells were incubated for 24 h and added to 100 µ of 0.01% neutral red dye. The cells were incubated for 3 h for pigment incorporation and fixed. Cells viability was determined by a spectroscopic (BioTek, Winooski, Vermont, USA with a 492-nm wavelength λ=492 nm. RESULTS: There were no statistical differences between the experimental groups and the CC and C- groups. CONCLUSION: Clear, pink, blue and green self-curing acrylic resins fabricated by means of the mass manipulation technique and mechanically polished are not cytotoxic. Neither the pigment added to the self-curing acrylic resin nor the factor of time influenced the cytotoxicity of the material.

  17. Thermal conductivity of catalyst layer of polymer electrolyte membrane fuel cells: Part 1 - Experimental study

    Science.gov (United States)

    Ahadi, Mohammad; Tam, Mickey; Saha, Madhu S.; Stumper, Jürgen; Bahrami, Majid

    2017-06-01

    In this work, a new methodology is proposed for measuring the through-plane thermal conductivity of catalyst layers (CLs) in polymer electrolyte membrane fuel cells. The proposed methodology is based on deconvolution of bulk thermal conductivity of a CL from measurements of two thicknesses of the CL, where the CLs are sandwiched in a stack made of two catalyst-coated substrates. Effects of hot-pressing, compression, measurement method, and substrate on the through-plane thermal conductivity of the CL are studied. For this purpose, different thicknesses of catalyst are coated on ethylene tetrafluoroethylene (ETFE) and aluminum (Al) substrates by a conventional Mayer bar coater and measured by scanning electron microscopy (SEM). The through-plane thermal conductivity of the CLs is measured by the well-known guarded heat flow (GHF) method as well as a recently developed transient plane source (TPS) method for thin films which modifies the original TPS thin film method. Measurements show that none of the studied factors has any effect on the through-plane thermal conductivity of the CL. GHF measurements of a non-hot-pressed CL on Al yield thermal conductivity of 0.214 ± 0.005 Wṡm-1ṡK-1, and TPS measurements of a hot-pressed CL on ETFE yield thermal conductivity of 0.218 ± 0.005 Wṡm-1ṡK-1.

  18. An Experimental Study on Concrete Flat Slabs Prestressed with Carbon Fibre Reinforced Polymer Sheets

    Directory of Open Access Journals (Sweden)

    Yin Shen

    2015-01-01

    Full Text Available Carbon fibre reinforced polymer (CFRP is currently used to reinforce buildings in civil engineering in the common forms of sheets, while the utilization efficiency of a CFRP materials greatly decreased when the CFRP material is directly bonded to the structure because of the lack of the effect of the exertion of a prestress. A paper spool-inspired anchoring method is proposed to overcome the shearing problem in the anchoring system through the friction between layers. Anchoring and jack-up tensioning devices for CFRP sheets are also designed and produced. A prestress is successfully applied to single and multiple CFRP sheets (80% tensioning strength is achieved, thus verifying the tensioning effect of the prestress. Based on these results, prestressed concrete flat slabs were designed with pretensioned CFRP sheets. The corresponding mechanical properties of the concrete flat slabs are tested to verify the feasibility of using CFRP sheets to apply a prestress. The results show that the uniformity of the fibre stress during the tensioning of the CFRP sheet is the key to the success of the application of the prestress.

  19. Occupational contact allergy to (meth)acrylates.

    Science.gov (United States)

    Geukens, S; Goossens, A

    2001-03-01

    Among 13,833 patients suspected of contact dermatitis examined during the years 1978-1999, occupational contact allergy to (meth)acrylates was diagnosed in 31 patients. The 3 most common sensitizers were ethyleneglycol dimethacrylate (17 positive patch tests), 2-hydroxyethyl methacrylate (14) and triethyleneglycol dimethacrylate (6). The aim of this report was to assess the different occupations and industries responsible for occupational sensitization to (meth)acrylates. 14 of the 31 patients work in the dental sector, either as a dentist or as a student of dental technology, where (meth)acrylate-containing dental prostheses and dental composites are mainly responsible for allergy to (meth)acrylates. An increasing trend in dermatological problems related to the expansion of the use of (meth)acrylates is clearly reflected in the patient population of our dermatology department.

  20. Asphaltenes-based polymer nano-composites

    Science.gov (United States)

    Bowen, III, Daniel E

    2013-12-17

    Inventive composite materials are provided. The composite is preferably a nano-composite, and comprises an asphaltene, or a mixture of asphaltenes, blended with a polymer. The polymer can be any polymer in need of altered properties, including those selected from the group consisting of epoxies, acrylics, urethanes, silicones, cyanoacrylates, vulcanized rubber, phenol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, imides, esters, cyanate esters, allyl resins.

  1. Surface Modification of PDMS and Plastics with Zwitterionic Polymers.

    Science.gov (United States)

    Tanaka, Mutsuo; Kurosawa, Shigeru

    2017-07-01

    Surface modification of PDMS, polycarbonate, and acrylic resin was examined using various methacryl polymers bearing sulfobetaine, phosphoryl choline, and oligoethylene glycol units. We have found that zwitterionic polymers are adsorbed on the PDMS surface treated with plasma. The surface of PDMS is stable to keep high hydrophilicity after a month of the modification. On the other hand, one of sulfobetaine polymers showed distinguished adsorption behavior in the case of polycarbonate surface treated with plasma. Suppression effect for nonspecific adsorption of BSA was evaluated using polycarbonate and acrylic resin modified with the polymers. The modified surfaces showed suppression effect for nonspecific adsorption of BSA compared with the surface only treated with plasma.

  2. Towards designing polymers for photovoltaic applications: A DFT and experimental study of polyazomethines with various chemical structures.

    Science.gov (United States)

    Wojtkiewicz, Jacek; Iwan, Agnieszka; Pilch, Marek; Boharewicz, Bartosz; Wójcik, Kamil; Tazbir, Igor; Kaminska, Maria

    2017-06-15

    Theoretical studies of polyazomethines (PAZs) with various chemical structures designated for photovoltaic applications are presented. PAZ energy levels and optical properties were calculated within density-functional theory (DFT and TDDFT) framework for 28 oligomers (monomer, dimer and trimer) of PAZs. The correlations between chemical structure of PAZ and location of its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels were examined. It turned out that the presence of triaminophenylene, dimethoxydiphenylene and fluorine group raises the orbital energies. As a consequence, it is a factor which improves the photovoltaic efficiency of solar cell built on the base of the corresponding PAZ and [6,6]-phenyl C 61 butyric acid methyl ester (PCBM). On the contrary, quinone, 1,3,5-triazine and perfluorophenylene groups lower orbital energies and have negative influence on the photovoltaic efficiency. Moreover, calculations for methyl, ethyl and butyl analogs of P3HT as well as polythiophenes were performed and compared with the results obtained for PAZs. In addition experimental data are presented, which cover optical, electrochemical and electrical transport properties of the studied PAZs, allowing to determine HOMO and LUMO energies of the polymers and their conductivity. Finally, comparison between calculated and experimental results were made and discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Towards designing polymers for photovoltaic applications: A DFT and experimental study of polyazomethines with various chemical structures

    Science.gov (United States)

    Wojtkiewicz, Jacek; Iwan, Agnieszka; Pilch, Marek; Boharewicz, Bartosz; Wójcik, Kamil; Tazbir, Igor; Kaminska, Maria

    2017-06-01

    Theoretical studies of polyazomethines (PAZs) with various chemical structures designated for photovoltaic applications are presented. PAZ energy levels and optical properties were calculated within density-functional theory (DFT and TDDFT) framework for 28 oligomers (monomer, dimer and trimer) of PAZs. The correlations between chemical structure of PAZ and location of its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels were examined. It turned out that the presence of triaminophenylene, dimethoxydiphenylene and fluorine group raises the orbital energies. As a consequence, it is a factor which improves the photovoltaic efficiency of solar cell built on the base of the corresponding PAZ and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). On the contrary, quinone, 1,3,5-triazine and perfluorophenylene groups lower orbital energies and have negative influence on the photovoltaic efficiency. Moreover, calculations for methyl, ethyl and butyl analogs of P3HT as well as polythiophenes were performed and compared with the results obtained for PAZs. In addition experimental data are presented, which cover optical, electrochemical and electrical transport properties of the studied PAZs, allowing to determine HOMO and LUMO energies of the polymers and their conductivity. Finally, comparison between calculated and experimental results were made and discussed.

  4. Fracture properties of an acrylic bone cement.

    Science.gov (United States)

    Bialoblocka-Juszczyk, E; Baleani, M; Cristofolini, L; Viceconti, M

    2008-01-01

    This study investigated experimentally the fracture properties, i.e., the fatigue strength, the resistance to crack propagation and the fracture toughness, of an acrylic bone cement (Cemex RX). The mean endurance limit was determined following the staircase method. The endurance limit was estimated at 9.2 MPa. The fatigue crack propagation rate was measured according to the ASTM E647 standard. The equation of the line fitting the crack growth per cycle (da/dN) versus the stress-intensity factor range (delta K), in a log-log graph, was used to calculate the empirical constants of Paris' law for the selected bone cement: da/dN (m/cycle) = 3.56 x 10(-7) x delta K (MPa x m1/2)5.79. This power-law relationship described well (R2 = 0.96) the growth rate in the stable crack growth region, i.e., in the mid delta K range. The fracture toughness K(IC) of the bone cement was determined according to the ASTM E399 standard. The K(IC) mean value was 1.38 MPa x m1/2. These experimental results provide the set of necessary inputs for numerical studies aimed to investigate the damage accumulation process in the mantle fixing cemented prostheses.

  5. Deep UV patterning of acrylic masters for molding biomimetic dry adhesives

    Science.gov (United States)

    Sameoto, D.; Menon, C.

    2010-11-01

    We present a novel fabrication method for the production of biomimetic dry adhesives that allows enormous variation in fiber shapes and sizes. The technology is based on deep-UV patterning of commercial acrylic with semi-collimated light available from germicidal lamps, and combined careful processing conditions, material selection and novel developer choices to produce relatively high-aspect-ratio fibers with overhanging caps on large areas. These acrylic fibers are used as a master mold for subsequent silicone rubber negative mold casting. Because the bulk acrylic demonstrates little inherent adhesion to silicone rubbers, the master molds created in this process do not require any surface treatments to achieve high-yield demolding of interlocked structures. Multiple polymers can be cast from silicone rubber negative molds and this process could be used to structure smart materials on areas over multiple square feet. Using direct photopatterning of acrylic allows many of the desired structures for biomimetic dry adhesives to be produced with relative ease compared to silicon-based molding processes, including angled fibers and hierarchical structures. Optimized fiber shapes for a variety of polymers can be produced using this process, and adhesion measurements on a well-characterized polyurethane, ST-1060, are used to determine the effect of fiber geometry on adhesion performance.

  6. Morphological alteration of microwave disinfected acrylic resins used for dental prostheses

    Science.gov (United States)

    Popescu, M. C.; Bita, B. I.; Avram, A. M.; Tucureanu, V.; Schiopu, P.

    2015-02-01

    In this paper we aim to perform a cross section morphological characterization of an acrylic polymer used for dental prostheses subjected to microwave disinfection. The method was largely investigated and the microbiological effectiveness is well established, but there are some issues regarding the in-depth alteration of the material. In our research, the surface roughness is insignificant and the samples were not polished or refined by any means. Two groups of 7 acrylic discs (20 mm diameter, 2 mm thickness) were prepared from a heat-cured powder. Half of the samples embedded a stainless steel reinforcement, in order to observe the changes at the interfaces between the polymer and metallic wire. After the gradual wet microwave treatment, the specimens - including the controls - were frozen in liquid nitrogen and broken into pieces. Fragments were selected for gold metallization to ensure a good contrast for SEM imaging. We examined the samples in cross section employing a high resolution SEM. We have observed the alterations occurred at the surface of the acrylic sample and at the interface with the metallic wire along with the increase of the power and exposure time. The bond configuration of acrylate samples was analysed by FTIR spectrometry.

  7. Scleral plug of biodegradable polymers containing tacrolimus (FK506) for experimental uveitis.

    Science.gov (United States)

    Sakurai, Eiji; Nozaki, Miho; Okabe, Komei; Kunou, Noriyuki; Kimura, Hideya; Ogura, Yuichiro

    2003-11-01

    To evaluate the efficacy of a biodegradable polymeric scleral plug containing the immunosuppressive agent, FK506, in a rabbit model for experimental uveitis. The scleral plugs were prepared by dissolving poly(DL-lactide-co-glycolide; PLGA) and FK506 (weight, 8.5 mg; length, 5 mm; 1% FK506). The release of FK506 was evaluated in vitro by spectrophotometry on days 1, 3, 7, 14, 21, and 35. In vivo, FK506 concentrations of the vitreous were measured by high performance liquid chromatography 2 and 4 weeks after intravitreous plug implantation in pigmented rabbits. Sixteen pigmented rabbits were immunized twice subcutaneously with 10 mg of Mycobacterium tuberculosis H37Ra antigen. Twelve days later, the right eyes of all rabbits were challenged with an intravitreal injection of 50 micro g of antigen. After the first challenge, the 16 eyes of 16 pigmented rabbits were divided into two groups. Scleral plugs were implanted into the vitreous of the right eye of eight rabbits. Eight control rabbits received a sham device. The aqueous protein concentrations and cell counts were determined on postchallenge days 7, 14, and 28. To simulated chronic inflammation, the eyes were rechallenged with intravitreal antigen on day 14 and were observed for 1 month. Inflammation of the anterior chamber and the vitreous were graded clinically by two masked observers. Retinal function was evaluated by electroretinography (ERG) and histologic examination. Clinical scores (anterior chamber cells, flare, and vitreous opacity) showed that treated eyes had significantly less inflammation than untreated eyes (Ptoxicity was detected, histopathologically and electroretinographically. After antigen rechallenge, inflammation in experimental eyes was still less than in control eyes. Intravitreal sustained-release of FK506 from a biodegradable polymeric scleral plug was highly effective in suppressing the inflammation of experimental uveitis in a rabbit model for at least 6 weeks. This device may be

  8. Experimental results with a natural gas cogeneration system using a polymer exchange membrane fuel cell

    Science.gov (United States)

    Radulescu, Mihai; Lottin, Olivier; Feidt, Michel; Lombard, Christophe; Noc, David Le; Doze, Stéphane Le

    This paper reports experimental results of an investigation of five identical CHP (combined heat and power) units using PEMFC (proton exchange membrane fuel cell) and running on natural gas. The natural gas is reformed locally to produce hydrogen. The net electric power is 4.5 kWe and the installations are designed for low temperature heat recovery (6 kW at 60 °C). The performances of the CHP units are analyzed in terms of electrical, thermal and total efficiencies. The electrical efficiency is low and it is shown that this is due mostly to the reforming process and to electric losses, while fuel cell performances are fully satisfying.

  9. Radiopurity measurement of acrylic for DEAP-3600

    Energy Technology Data Exchange (ETDEWEB)

    Nantais, C. M.; Boulay, M. G. [Department of Physics, Engineering Physics, and Astronomy, Queen' s University, Kingston, Ontario K7L 3N6 (Canada); Cleveland, B. T. [SNOLAB, Lively, Ontario P3Y 1N2 Canada and Department of Physics, Laurentian University, Sudbury, Ontario P3E 2C6 (Canada)

    2013-08-08

    The spherical acrylic vessel that contains the liquid argon target is the most critical detector component in the DEAP-3600 dark matter experiment. Alpha decays near the inner surface of the acrylic vessel are one of the main sources of background in the detector. A fraction of the alpha energy, or the recoiling nucleus from the alpha decay, could misreconstruct in the fiducial volume and result in a false candidate dark matter event. Acrylic has low levels of inherent contamination from {sup 238}U and {sup 232}Th. Another background of particular concern is diffusion of {sup 222}Rn during manufacturing, leading to {sup 210}Pb contamination. The maximum acceptable concentrations in the DEAP-3600 acrylic vessel are ppt levels of {sup 238}U and {sup 232}Th equivalent, and 10{sup −8} ppt {sup 210}Pb. The impurities in the bulk acrylic will be measured by vaporizing a large quantity of acrylic and counting the concentrated residue with ultra-low background HPGe detectors and a low background alpha spectrometer. An overview of the acrylic assay technique is presented.

  10. Grafted natural polymer as new drag reducing agent: An experimental approach

    Directory of Open Access Journals (Sweden)

    Abdulbari Hayder A.

    2012-01-01

    Full Text Available The present investigation introduces a new natural drag reducing agent which has the ability to improve the flow in pipelines carrying aqueous or hydrocarbon liquids in turbulent flow. Okra (Abelmoschus esculentus mucilage drag reduction performance was tested in water and hydrocarbon (gas-oil media after grafting. The drag reduction test was conducted in a buildup closed loop liquid circulation system consists of two pipes 0.0127 and 0.0381 m Inside Diameter (ID, four testing sections in each pipe (0.5 to 2.0 m, tank, pump and pressure transmitters. Reynolds number (Re, additive concentration and the transported media type (water and gas-oil, were the major drag reduction variables investigated. The experimental results show that, new additive drag reduction ability is high with maximum percentage of drag reduction (%Dr up to 60% was achieved. The experimental results showed that the drag reduction ability increased by increasing the additive concentration. The %Dr was found to increase by increasing the Re by using the water-soluble additive while it was found to decrease by increasing the Re when using the oil-soluble additive. The %Dr was higher in the 0.0381 m ID pipe. Finally, the grafted and natural mucilage showed high resistance to shear forces when circulated continuously for 200 seconds in the closed-loop system.

  11. Thermodynamic Interactions between Polystyrene and Long-Chain Poly(n-Alkyl Acrylates) Derived from Plant Oils.

    Science.gov (United States)

    Wang, Shu; Robertson, Megan L

    2015-06-10

    Vegetable oils and their fatty acids are promising sources for the derivation of polymers. Long-chain poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) are readily derived from fatty acids through conversion of the carboxylic acid end-group to an acrylate or methacrylate group. The resulting polymers contain long alkyl side-chains with around 10-22 carbon atoms. Regardless of the monomer source, the presence of alkyl side-chains in poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) provides a convenient mechanism for tuning their physical properties. The development of structured multicomponent materials, including block copolymers and blends, containing poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) requires knowledge of the thermodynamic interactions governing their self-assembly, typically described by the Flory-Huggins interaction parameter χ. We have investigated the χ parameter between polystyrene and long-chain poly(n-alkyl acrylate) homopolymers and copolymers: specifically we have included poly(stearyl acrylate), poly(lauryl acrylate), and their random copolymers. Lauryl and stearyl acrylate were chosen as model alkyl acrylates derived from vegetable oils and have alkyl side-chain lengths of 12 and 18 carbon atoms, respectively. Polystyrene is included in this study as a model petroleum-sourced polymer, which has wide applicability in commercially relevant multicomponent polymeric materials. Two independent methods were employed to measure the χ parameter: cloud point measurements on binary blends and characterization of the order-disorder transition of triblock copolymers, which were in relatively good agreement with one another. The χ parameter was found to be independent of the alkyl side-chain length (n) for large values of n (i.e., n > 10). This behavior is in stark contrast to the n-dependence of the χ parameter predicted from solubility parameter theory. Our study complements prior work investigating the interactions between

  12. Photo-Reversible Supramolecular Hydrogels Assembled by α-Cyclodextrin and Azobenzene Substituted Poly(acrylic acid)s

    NARCIS (Netherlands)

    Wang, Mingwei; Zhang, Xiaojun; Li, Li; Wang, Junyou; Wang, Jie; Ma, Jun; Yuan, Zhenyu; Lincoln, Stephen F.; Guo, Xuhong

    2016-01-01

    Photo-reversible supramolecular hydrogels based on the mixture of α-cyclodextrin (α-CD) and azobenzene (Azo) substituted poly(acrylic acid) s were prepared. Effects of substitution degree of Azo, polymer concentration and tethered chain length on the reversible sol-gel transition of these

  13. Electrokinetic characterization of poly(acrylic acid) and poly(ethylene oxide) brushes in aqueous electrolyte solutions

    NARCIS (Netherlands)

    Zimmermann, R.; Norde, W.; Cohen Stuart, M.A.; Werner, C.

    2005-01-01

    Surfaces carrying hydrophilic polymer brushes were prepared from poly(styrene)-poly(acrylic acid) and poly(styrene)-poly(ethylene oxide) diblock copolymers, respectively, using a Langmuir-Blodgett technique and employing poly(styrene)-coated planar glass as substrates. The electrical properties of

  14. Structural Parameters and Swelling Behavior of pH Sensitive Poly(acrylamide-co-acrylic acid) Hydrogels

    OpenAIRE

    Thakur, A.; Wanchoo, R. K.; Singh, P

    2011-01-01

    In the present work, hydrogels based on acrylamide (AAm) and acrylic acid (AAc), crosslinked with N,N’-methylenebisacrylamide (MBAAm) were prepared by free radical polymerization in solution. The effect of initial AAm/AAc mole ratio and nominal crosslinking ratio (moles of crosslinking agent/moles of polymer repeat unit) on the dynamic and equilibrium swelling behaviour of hydrogels was investigated. Hydrogels were characterized by the polymer volume fraction in the swollen state (ν2,s ), the...

  15. Comparison of patient satisfaction with acrylic and flexible partial dentures.

    Science.gov (United States)

    Akinyamoju, Clara Arianta; Ogunrinde, Tunde Joshua; Taiwo, Juliana Obontu; Dosumu, Oluwole Oyekunle

    2017-01-01

    Restoration of partial edentulous mouth may be done using a variety of treatment options. Removable partial denture (RPD) is commonly used because of its availability. RPDs from flexible resins unlike those from acrylic engage hard and soft tissue undercuts and feel more comfortable in the mouth. The aim of the study was to compare satisfaction with dentures made from these two types of materials. It was a quasi-experimental study among thirty patients at the Prosthetics Clinic, University College Hospital, Ibadan. Patients aged 16 years or more, requiring RPDs with one to three missing teeth in the anterior region of either the upper or lower arch participated. A modified semi-structured interviewer-administered questionnaire was used to collect data on sociodemographics and oral health variables. The level of satisfaction was assessed using a visual analogue scale. Data were analysed using descriptive and multivariate statistics at a significance level of P dentures, 6 (20.0%) with acrylic dentures while 3 (10.0%) were equally satisfied with both types of dentures (P = 0.04). Subjects were more satisfied with the flexible RPD than the acrylic resin RPD.

  16. Improved biotribological properties of PEEK by photo-induced graft polymerization of acrylic acid.

    Science.gov (United States)

    Zhao, Xiaoduo; Xiong, Dangsheng; Wang, Kun; Wang, Nan

    2017-06-01

    The keys of biomaterials application in artificial joints are good hydrophilicity and wear resistance. One kind of the potential bio-implant materials is polyetheretherketone (PEEK), which has some excellent properties such as non-toxic and good biocompatibility. However, its bioinert surface and inherent chemical inertness hinder its application. In this study, we reported an efficient method for improving the surface wettability and wear resistance for PEEK, a layer of acrylic acid (AA) polymer brushes on PEEK surface was prepared by UV-initiated graft polymerization. The effects of different grafting parameters (UV-irradiation time/AA monomer solution concentration) on surface characteristics were clearly investigated, and the AA-g-PEEK specimens were examined by ATR-FTIR, static water contact angle measurements and friction tests. Our results reveal that AA can be successfully grafted onto the PEEK surface after UV irradiation, the water wettability and tribological properties of AA-g-PEEK are much better than untreated PEEK because that AA is a hydrophilic monomer, the AA layer on PEEK surface can improve its bearing capacity and reduce abrasion. This detailed understanding of the grafting parameters allows us to accurately control the experimental products, and this method of surface modification broadens the use of PEEK in orthopedic implants. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Design and evaluation of acrylate polymeric carriers for fabrication of pH-sensitive microparticles.

    Science.gov (United States)

    Arya, Amit; Majumdar, Dipak K; Pathak, Dharam Pal; Sharma, Anil K; Ray, Alok R

    2017-02-01

    Colon-targeted microparticles loaded with a model anti-inflammatory drug were fabricated using especially designed acrylic acid-butyl methacrylate copolymers. Microparticles were prepared by oil-in-oil solvent evaporation method using Span 80 as emulsifier. Microparticles were found to be spherical in shape, hemocompatible and anionic with zeta potential of -27.4 and -29.0 mV. Entrapment of drug in the microparticles was confirmed by Fourier transform infrared (FTIR) spectroscopy. However, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) revealed amorphous nature of microparticles due to the dilution effect of amorphous polymer. The microparticles released less than 5% drug at pH 1.2, while more than 90% of the drug load was released at pH 7.4. This suggested the colon targeting nature of the formulations. In experimentally developed colitis in Wistar rats, the microparticle formulation showed significant reduction (p < .05) in the disease activity score (disease symptoms), the colon-to-body weight ratio (tissue edema) and the myeloperoxidase, tumor necrosis factor (TNF)-α and interleukin (IL)-1β activities.

  18. High Solid Contents Copoly (Styrene/Butyl Acrylate)-Cloisite 30B Nanocomposites

    OpenAIRE

    M. Mirzataheri

    2013-01-01

    Higher solid contents (20 % and 40 %) nanocomposites of poly (styrene-co-butyl acrylate) including higher content of Cloisite 30B (7 wt% and 10 wt %) were prepared via miniemulsion polymerization. Stability of the final latexes proved outstanding combination of polymerization procedure and surfactants. Morphological studies revealed by TEM, SAX and XRD showed three structures of core-shell, armored and individual dispersion of clay layers within the polymer particles. The effect of Cloisite 3...

  19. The effect of disinfection procedures on flexural properties of denture base acrylic resins.

    Science.gov (United States)

    Asad, T; Watkinson, A C; Huggett, R

    1992-07-01

    This study evaluates the effects of long-term disinfection immersion on the flexural properties of denture base resins; it was conducted against a background of increasing awareness of the importance of cross-infection control in dental clinics and laboratories. The transverse bend testing procedure used followed that specified in the International Standard for denture base polymers. The results demonstrate that alcohol-based disinfectants are not suitable for use with denture base materials of non-cross-linked acrylic resin.

  20. Experimental Study of Concrete-filled Carbon Fiber Reinforced Polymer Tube with Internal Reinforcement under Axially Loading

    Directory of Open Access Journals (Sweden)

    Wenbin SUN

    2014-12-01

    Full Text Available Comparing with the circular concrete columns confined with fiber reinforced polymer (FRP wrap or tube, the rectilinear confined columns were reported much less. Due to the non-uniform distribution of confining pressure in the rectilinear confined columns, the FRP confinement effectiveness was significant reduced. This paper presents findings of an experimental program where nine prefabricated rectangular cross-section CFRP tubes with CFRP integrated crossties filled concrete to form concrete-filled FRP tube (CFFT short columns and three plain concrete control specimens were tested. All specimens were axially loaded until failure. The rest results showed that the stress-strain curves of CFFTs consisted of two distinct branches, an ascending branch before the concrete peak stress was reaches and a second branch that terminated when the tube ruptured, and that the CFFTs with integrated crossties experienced most uniform confinement pressure distribution. Test research also found that the stress-strain curves of CFFTs indicated an increase in ductility. These demonstrate that this confinement system can produce higher lateral confinement stiffness. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6035

  1. Ampholytic terpolymers of acrylamide with sodium acrylate and (2-ethacryloyloxyethyl) trimethylammonium chloride. Synthesis with {sup 60}Co {gamma}-ray and polymerization kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Ge Xuewu; Sheng Minya; Ye Qiang; Xu Xiangling; Zhang Zhicheng [Department of Applied Chemistry, University of Science and Technology of China, Hefei, Anhui (China)

    1999-12-01

    A new terpolymer of acrylamide with sodium acrylate and (2-methacryloyloxyethyl) trimethylammonium chloride initiated with {sup 60}Co {gamma}-ray was prepared in inverse emulsion. Polymerization conversion was studied dilatometrically and molecular weight was determined viscometrically. The effects of dose rate, monomer concentration, emulsifier content, temperature, etc. on the polymerization rate or conversion and the molecular weight of polymer were examined. The rate of polymerization (Rp) can be represented by Rp {proportional_to} D{sup 1.03}[M]{sup 0.69}[E]{sup -0.02}. The overall activation energy for the rate of polymerization is 12.90 kJ mol{sup -1} (33-56degC). Based on these experimental results, aspects of the polymerization mechanisms are discussed. (author)

  2. Properties of solvent-borne acrylic pressure-sensitive adhesives synthesized by a simple approach

    Directory of Open Access Journals (Sweden)

    2009-12-01

    Full Text Available Acrylic polymers are widely used for fabricating pressure-sensitive adhesives (PSAs with the inherent unique advantages of transparency and superior intrinsic adhesive properties over other polymer-based adhesives. In this study, we have developed and evaluated a method of obtaining by radical copolymerization PSAs for liquid crystalline (LCD applications. Various factors including the amount of monomers, amount of cross-linker, coating weight, dwell time and thermal treatment are investigated for further optimizing the properties of acrylic polymer based PSAs to meet the emerging strict requirements for practical uses related mainly to holding powder and peel strength. The results illustrate that novel crosslinking reagents coupled with the thermal treatment at 70°C can make the resultant PSAs with the improved adhesive properties. The coating weight variation from 10 to 40 g/m2 can significantly enhance the peel strength from 4.0 g/25 mm to 12.5 g/25 mm with about 310% increment. If the dwell time of PSAs with cross-linking reagent is more than 10 hrs, the peel strength can be reduced down to a suitable value to meet the criterion for use. Therefore, acrylic PSAs with peel strength less than 20 g/25 mm and holding power above 120 hrs were successfully synthesized by elaborately designing the reaction system, which are practically applicable for advanced industrial applications.

  3. Probing the effects of experimental conditions on the character of drug-polymer phase diagrams constructed using Flory-Huggins theory.

    Science.gov (United States)

    Donnelly, Conor; Tian, Yiwei; Potter, Catherine; Jones, David S; Andrews, Gavin P

    2015-01-01

    Amorphous drug-polymer solid dispersions have been found to result in improved drug dissolution rates when compared to their crystalline counterparts. However, when the drug exists in the amorphous form it will possess a higher Gibb's free energy than its associated crystalline state and can recrystallize. Drug-polymer phase diagrams constructed through the application of the Flory Huggins (F-H) theory contain a wealth of information regarding thermodynamic and kinetic stability of the amorphous drug-polymer system. This study was aimed to evaluate the effects of various experimental conditions on the solubility and miscibility detections of drug-polymer binary system. Felodipine (FD)-Polyvinylpyrrolidone (PVP) K15 (PVPK15) and FD-Polyvinylpyrrolidone/vinyl acetate (PVP/VA64) were the selected systems for this research. Physical mixtures with different drug loadings were mixed and ball milled. These samples were then processed using Differential Scanning Calorimetry (DSC) and measurements of melting point (Tend) and glass transition (Tg) were detected using heating rates of 0.5, 1.0 and 5.0°C/min. The melting point depression data was then used to calculate the F-H interaction parameter (χ) and extrapolated to lower temperatures to complete the liquid-solid transition curves. The theoretical binodal and spinodal curves were also constructed which were used to identify regions within the phase diagram. The effects of polymer selection, DSC heating rate, time above parent polymer Tg and polymer molecular weight were investigated by identifying amorphous drug miscibility limits at pharmaceutically relevant temperatures. The potential implications of these findings when applied to a non-ambient processing method such as Hot Melt Extrusion (HME) are also discussed.

  4. Synthesis and electromechanical characterization of a new acrylic dielectric elastomer with high actuation strain and dielectric strength

    Science.gov (United States)

    Hu, Wei; Niu, Xiaofan; Yang, Xinguo; Zhang, Naifang; Pei, Qibing

    2013-04-01

    Dielectric Elastomers (DEs) can be actuated under high electric field to produce large strains. Most high-performing DE materials such as the 3M™ VHB™ membranes are commercial products designed for industrial pressure-sensitive adhesives. The limited knowledge of the exact chemical structures of these commercial materials has made it difficult to understand the relationship between molecular structures and electromechanical properties. In this work, new acrylic elastomers based on n-butyl acrylate and acrylic acid were synthesized from monomer solutions by UV-initiated bulk polymerization. The new acrylic copolymers have a potential to obtain high dielectric constant, actuation strain, dielectric strength, and a high energy density. Silicone and ester oligomer diacrylates were also added onto the copolymer structures to suppress crystallization and to crosslink the polymer chains. Four acrylic formulations were developed with different amounts of acrylic acid. This gives a tunable stiffness, while the dielectric constant is varied from 4.3 to 7.1. The figure-of-merit performance of the best formulation is 186 % area strain, 222 MV/m of dielectric strength, and 2.7 MJ/m3 of energy density. To overcome electromechanical instability, different prestrain ratios were investigated, and under the optimized prestrain, the material has a lifetime of thousands of cycles at 120 % area strain.

  5. Resistance of acrylic vessel to gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Andre Cavalcanti; Menezes, Maria Angela de B.C.; Pereira, Marcio Tadeu; Rocha, Nirlando Antonio; Vilela, Jefferson Jose, E-mail: andreccarneiro@gmail.com, E-mail: menezes@cdtn.br, E-mail: mtp@cdtn.br, E-mail: nar@cdtn.br, E-mail: jjv@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Braga, Mario Roberto Martins S.S., E-mail: mariomartins@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2013-07-01

    This paper describes the preliminary studies made in acrylic material in order to verify the effects of radiolysis in acrylic recipients in which the uranium ore standards are conditioned and check if the material is able to keep the {sup 222}Rn inside the vessel. The preliminary results after gamma irradiation of two kinds of recipients indicate no differences between the vessels irradiated and the ones no irradiated, related to color changes and tension resistance. (author)

  6. Experimental simulation of radiation damage of polymers in space applications by cosmic-ray-type high energy heavy ions and the resulting changes in optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, U.H.; Ensinger, W., E-mail: ensinger@ca.tu-darmstadt.de

    2015-12-15

    Devices operating in space, e.g. in satellites, are being hit by cosmic rays. These include so-called HZE-ions, with High mass (Z) and energy (E). These highly energetic heavy ions penetrate deeply into the materials and deposit a large amount of energy, typically several keV per nm range. Serious damage is created. In space vehicles, polymers are used which are degraded under ion bombardment. HZE ion irradiation can experimentally be simulated in large scale accelerators. In the present study, the radiation damage of aliphatic vinyl- and fluoro-polymers by heavy ions with energies in the GeV range is described. The ions cause bond scission and create volatile small molecular species, leading to considerable mass loss of the polymers. Since hydrogen, oxygen and fluorine-containing molecules are created and these elements are depleted, the remaining material is carbon-richer than the original polymers and contains conjugated CC double bonds. This process is investigated by measuring the optical band gap with UV–Vis absorption spectrometry as a function of ion fluence. The results show how the optical band gaps shift from the UV into the Vis region upon ion irradiation for the different polymers.

  7. Influência da adição da goma arábica em filmes isolados de polímero acrílico: estudo das propriedades de intumescimento e de permeabilidade Influence of arabic gum in acrylic polymer isolated films: study of swelling properties and permeability

    Directory of Open Access Journals (Sweden)

    Victor Gustavo Santos Gabas

    2003-12-01

    Full Text Available Goma arábica associada ao polímero acrílico Eudragit RS30D® na formação de filmes isolados foram obtidos e investigados como material potencialmente adequado à liberação modificada de fármacos. Foram preparadas dispersões aquosas de 4% (p/v e o citrato de trietila (20% massa polímero acrílico foi usado como plastificante. Dispersões foram vertidas em placa de Nylon revestida com Teflon® e colocadas em estufa a 60 ºC. A determinação do índice de intumescimento (Ii% em fluidos de simulação gástrica (FSG e intestinal (FSI, além da permeabilidade ao vapor d'água (TVA foram avaliadas. As dispersões propostas apresentaram habilidades filmogênicas. O polissacarídeo favoreceu, proporcionalmente à sua concentração, o grau de hidratação e a permeabilidade ao vapor d'água dos filmes formados. Estas particularidades observadas sugerem que os filmes constituídos por estas associações garantem acessibilidade com maior intensidade, quando comparado ao polimetacrilato individualmente, condição essa indispensável para uma biodegradação efetiva, em especial às regiões distais do trato gastrintestinal.Arabic gum combined with polymeric acrylic Eudragit RS30D® in isolated films for film coating, were obtained and investigated as potential material adapted for drug delivery systems. They were prepared aqueous dispersions of 4% (p/v, the triethyl citrate (20% w/w of the methacrylate polymer it was used with plasticizer. Sample of dispersions were poured over plate of Nylon covered with Teflon and placed in an air circulated oven at 60 ºC. Determination of the swelling index (Is% in fluids of gastric (SGF or intestinal simulation or intestinal (SIF, and the permeability to the water vapour (TVA were investigated. An increase in the amount of added polysaccharide favored the degree of hydration/swelling and permeability of the formed films. These observed particularities suggest that the films constituted by these

  8. Efficacy of antimicrobial photodynamic therapy in the disinfection of acrylic denture surfaces: A systematic review.

    Science.gov (United States)

    Varela Kellesarian, Sergio; Abduljabbar, Tariq; Vohra, Fahim; Malmstrom, Hans; Yunker, Michael; Varela Kellesarian, Tammy; Romanos, Georgios E; Javed, Fawad

    2017-03-01

    The aim of the present systematic review was to assess the efficacy of antimicrobial photodynamic therapy (aPDT) in the disinfection of acrylic denture surfaces. IN order to address the focused question: "Is aPDT more effective in decontaminating denture surfaces compared with traditional denture-disinfection techniques?" an electronic search without time or language restrictions was conducted up to November 2016 in indexed databases using different key words. The exclusion criteria included qualitative and/or quantitative reviews, case reports, case series, commentaries, letters to the editor, interviews, and updates. A total of 14 studies were included and processed for data extraction, out of which 1 study was a randomized clinical trial and 13 studies were performed in vitro. Results from 12 experimental studies reported that aPDT was effective in reducing bacteria and/or yeast cultured in single or multispecies biofilm growth on acrylic resin specimens. One experimental study reported selective microorganism reduction on acrylic resin after aPDT. One clinical randomized control trial reported that aPDT presented similar microorganism reduction compared with oral antifungal medication for the disinfection of denture surfaces. The role of aPDT in the disinfection of acrylic resin surfaces is unclear. From a clinical perspective further randomized control trials are needed to assess the efficacy of aPDT in the disinfection of acrylic resin surfaces. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Radiation-induced synthesis of poly(acrylic acid) nanogels

    Science.gov (United States)

    Matusiak, Malgorzata; Kadlubowski, Slawomir; Ulanski, Piotr

    2018-01-01

    Nanogel is a two-component system of a diameter in the range of tens of nanometers, consisting of an intramolecularly crosslinked polymer chain and solvent, typically water, filling the space between segments of the macromolecule. Microgels are bigger than nanogels and their size range is between 100 nm to 100 μm. One of the methods used for synthesizing nanogels is linking the segments of a single macromolecule with the use of ionizing radiation, by intramolecular recombination of radiation-generated polymer radicals. The main advantage of this technique is absence of monomers, catalysts, surfactants or crosslinking agents. This method is an interesting alternative way of synthesizing polymeric carriers for biomedical applications. The aim of the study was radiation synthesis and characterization of poly(acrylic acid) - PAA - nanogels and microgels. The physico-chemical properties were described by determination of weight-average molecular weight and dimensions (radius of gyration, hydrodynamic radius) of the nanogels and microgels. Influence of polymer concentration and dose on these parameters was analyzed. Adjusting the PAA concentration and absorbed dose, one can control the molecular weight and dimensions of nanogels. The solutions of PAA were irradiated with two sources of ionizing radiation: γ-source and electron accelerator. The former method yields mainly microgels due to prevailing intermolecular crosslinking, while the latter promotes intramolecular recombination of PAA-derived radicals and in consequence formation of nanogels. In the future radiation-synthesized PAA nanogels, after functionalization, will be tested as carriers for delivering radionuclides to the tumor cells.

  10. Solubility of dense CO2 in two biocompatible acrylate copolymers

    Directory of Open Access Journals (Sweden)

    A. R. C. Duarte

    2006-06-01

    Full Text Available Biocompatible polymers and copolymers are frequently being used as part of controlled delivery systems. These systems can be prepared using a "clean and environment friendly" technology like supercritical fluids. One great advantage of this process is that compressed carbon dioxide has excellent plasticizing properties and can swell most biocompatible polymeric matrixes, thus promoting drug impregnation processes. Mass sorption of two acrylate biocompatible copolymers contact with supercritical carbon dioxide is reported. Equilibrium solubility of dense carbon dioxide in poly(methylmethacrylate-co-ethylhexylacrylate and poly(methylmethacrylate-co-ethylhexylacrylate-co-ethyleneglycoldimethacrylate was studied by a static method at 10.0 MPa and 313 K. The reticulated copolymer had Fickean behavior and its diffusion coefficient was calculated, under operating conditions.

  11. Scintillation properties of acrylate based plastic scintillator by photoploymerization method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Hwan [Dept. of Radiological Science, Cheongju University, Cheongju (Korea, Republic of); Lee, Joo Il [Dept. of of Radiology, Daegu Health College, Daegu (Korea, Republic of)

    2016-12-15

    In this study, we prepared and characterized a acrylate based UV-curable plastic scintillator. It was used co-polymers TMPTA, DHPA and Ultima GoldTM LLT organic scintillator. The emission spectrum of the plastic scintillator was located in the range of 380⁓520 nm, peaking at 423 nm. And the scintillator is more than 50% transparent in the range of 400⁓ 800 nm. The emission spectrum is well match to the quantum efficiency of photo-multiplier tube and the fast decay time of the scintillation is 12 ns, approximately. This scintillation material provides the possibility of combining 3D printing technology, and then the applications of the plastic scintillator may be expected in human dosimetry etc.

  12. Investigation of small molecular weight poly(acrylic acid) adsorption on γ-alumina

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lei; Luo, Shi-Zhong [College of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065 (China); Wang, Bin, E-mail: bin_wang@scu.edu.cn [College of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065 (China); Guo, ZhanHu [Chemical and Biomolecular Engineering Department, University of Tennessee, Knoxville, TN 37996 (United States)

    2015-08-01

    Highlights: • Small molecular weight poly(acrylic acid) incorporated on γ-alumina. • PAA adsorbed primarily on outer surface of alumina at low pH. • PAA infiltrated inside alumina pore at high pH. • Polymer chain reptation motion during the infiltration. - Abstract: The interactions between poly(acrylic acid) (PAA) and alumina have been widely investigated. In this study, the pattern of small molecular weight PAA (M{sub W} 3000) interaction with γ-alumina has been dissected. The alumina/PAA hybrids were prepared at pH 4.0, 5.5, and 7.0, respectively. Nitrogen absorption–desorption analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and elemental analysis were conducted to illustrate the characteristics of the hybrids. At pH 4.0, the coiled PAA conformation yielded polymer adsorption primarily on alumina outer surface. At higher pH values, the more stretched PAA molecules were able to infiltrate inside the alumina pores. The phenomenon is explained by the polymer chain reptation motion model. Coiled polymer chains are not oriented enough to penetrate the oxide pore channels. In contrary, stretched polymer chains are more likely to move along the pore channels.

  13. Fluorescently Labeled Branched Polymers and Thermal Responsive Nanoparticles for Live Cell Imaging

    NARCIS (Netherlands)

    Zhou, D.; Ma, Y.; Poot, Andreas A.; Dijkstra, Pieter J.; Feijen, Jan

    2012-01-01

    Branched poly(methoxy-PEG acrylate) and thermally responsive poly(methoxy-PEG acrylate)-block-poly(N-isopropylacrylamide) are synthesized by RAFT polymerization. After reduction, these polymers are fluorescently labeled by reacting the free thiol groups with N-(5-fluoresceinyl)maleimide. As shown by

  14. Surface modification of carbon nanotubes using 3-aminopropyltriethoxysilane to improve mechanical properties of nanocomposite based polymer matrix: Experimental and Density functional theory study

    Science.gov (United States)

    Hamed Mashhadzadeh, A.; Fereidoon, Ab.; Ghorbanzadeh Ahangari, M.

    2017-10-01

    In current study we combined theoretical and experimental studies to evaluate the effect of functionalization and silanization on mechanical behavior of polymer-based/CNT nanocomposites. Epoxy was selected as thermoset polymer, polypropylene and poly vinyl chloride were selected as thermoplastic polymers. The whole procedure is divided to two sections . At first we applied density functional theory (DFT) to analyze the effect of functionalization on equilibrium distance and adsorption energy of unmodified, functionalized by sbnd OH group and silanized epoxy/CNT, PP/CNT and PVC/CNT nanocomposites and the results showed that functionalization increased adsorption energy and reduced the equilibrium distance in all studied nanocomposites and silanization had higher effect comparing to OH functionalizing. Then we prepared experimental samples of all mentioned nanocomposites and tested their tensile and flexural strength properties. The obtained results showed that functionalization increased the studied mechanical properties in all evaluated nanocomposites. Finally we compared the results of experimental and theoretical sections with each other and estimated a suitable agreement between these parts.

  15. Conductivity and phase morphology of carbon black-filled immiscible polymer blends under creep: an experimental and theoretical study.

    Science.gov (United States)

    Pan, Yamin; Liu, Xianhu; Hao, Xiaoqiong; Schubert, Dirk W

    2016-11-30

    Blends of carbon black (CB)-filled co-continuous immiscible polystyrene/poly(methyl-methacrylate) (PS/PMMA) with a PS/PMMA ratio of 50/50 and CB selectively located in the PS phase have been prepared by melt blending. The simultaneous evolution of conductivity and phase morphology of blend composites was investigated under shear and in the quiescent state at 200 °C. It was found that shear deformation had a significant influence on the conductivity of the unfilled PS/PMMA blend and its composites, which was attributed to the change of phase morphology during shear. After the shear stress of 10 kPa, the conductivity of PS/PMMA blends filled with 2 vol% of CB decreased by about two orders of magnitude and the phase morphology transformed from a fine co-continuous structure into a highly elongated lamellar structure. The deformation of phase morphology and the decrease of conductivity were weakened upon decreasing the shear stress or increasing the CB concentration. During subsequent recovery, pronounced phase structure coarsening was observed in the mixture and the conductivity increased as well. A simple model describing the behavior of conductivity under shear deformation was derived and utilized for the description of the experimental data. For the first time, the Burgers model was used to describe the conductivity, and the viscoelastic and viscoplastic parameters were deduced by fitting the conductivity under shear. The results obtained in this study provide a deeper insight into the evolution of phase structure in the conductive polymer blend composite induced by shear deformation.

  16. Comparison of bond strength of composite and acrylic teeth to heat-cured and

    Directory of Open Access Journals (Sweden)

    Amirjan A

    2011-02-01

    Full Text Available "nBackground and Aims: Failure of bonding between artificial teeth and denture base material is a considerable problem for patients who wear dentures. Because of the cost of denture repair and the expensive price of foreign artificial teeth, this study was designed to compare the bond strength of composite and acrylic artificial teeth with heat-cured and auto-polymerized denture base resins."nMaterials and Methods: In this experimental and in vitro study, two type of acrylic resin (heat-cured: Selectaplus H/ Trevalon, Dentsply and auto-polymerized: Rapid Repair, Dentsply and four artificial teeth (acrylic Marjan New, composite Glamour teeth which both of them are Iranian and Ivoclar acrylic and composite teeth were used. Therefore, 8 groups of 14 specimens each were evaluated. A shear bond strenghth test in a Universal Testing Machine was used. Data were analyzed using the 2-way ANOVA test."nResults: The bond strengths of acrylic teeth (Marjan New and Ivoclar to heat-cured resin were similar (P=0.632 and statistically higher than those of composite teeth (Glamour and Ivoclar. Acrylic teeth (Marjan New and Ivoclar and Glamour teeth had similar bond strength to auto-polymerized resin, which showed the highest bond strength values. Ivoclar composite teeth showed significantly the lowest bond strength (P<0.05. All acrylic teeth had the highest mean bond strengths to heat-cured resin which were significantly different from that of "nauto-polymerized resin (P<0.05. However, the bond strengths of all composite teeth to both denture base resins were not significantly different (P>0.05."nConclusion: Based on the results of this study, the type of denture base material and artificial tooth may influence the failure load.

  17. Experimental investigations and numerical simulations for an open channel flow of a weak elastic polymer solution around a T-profile

    Energy Technology Data Exchange (ETDEWEB)

    Balan, C.; Neagoe, A.; Nistoran, D. [Hydraulics and Hydraulic Machinery Department - REOROM Group, University ' ' Politehnica' ' of Bucharest, Splaiul Independentei 313, 79590, Bucharest (Romania); Legat, V. [University of Louvain-la-Neuve - Center for Systems Engineering Applied Mechanics (CESAME), Batiment Euler, Av. Georges Lemaitre 4, 1348, Louvain-la-Neuve (Belgium)

    2004-03-01

    The present paper is concerned with experimental and numerical investigations of planar complex flows of ''weak'' elastic polymer solutions (whose concentration are below the critical overlap concentration), characterised by small relaxation times ({lambda}<0.1 s) and almost constant shear viscosities for small and medium shear rates. The main aim of the study is to detect to what extent a very small amount of elasticity present in a viscous fluid can influence its behaviour in complex flows, without introducing major modifications of classical rheological tests. The samples are polymer solutions of low PIB molecular weight dissolved in highly viscous Newtonian mineral oil. The analysed motion is steady, and takes place in an open channel around a ''T'' profile. Maximum values of the characteristic parameters for the experiments, the Reynolds and Weissenberg numbers, were 45 and 0.1, respectively. The experiments show a decrease of the wake length downstream the profile for weak elastic solutions in comparison to the Newtonian solvent. Actually, the same wake length as in the Newtonian case was obtained for tested polymer solutions, but at higher Re numbers. Numerical simulations using the Giesekus model predict the same behaviour and are consistent with experiments from both qualitative and quantitative point of views. The results of research conclude that, even in small amounts, the presence of elasticity in pure viscous liquids induces quantitative changes from Newtonian flow in complex dominant elongational flows, at elongational rates for which the sudden thickening of extensional viscosity is remarkable. The study is important, since it should enable better understanding and modelling of viscoelastic flows that involve dilute polymer solutions, or fluids with similar rheology; biofluid mechanics being one area of application of this research. Corroboration of experimental flow visualization with numerical simulation is

  18. Michael Addition Polymerization of Trifunctional Amine and Acrylic Monomer: A Versatile Platform for Development of Biomaterials.

    Science.gov (United States)

    Cheng, Weiren; Wu, Decheng; Liu, Ye

    2016-10-10

    Michael addition polymerizations of amines and acrylic monomers are versatile approaches to biomaterials for various applications. A combinatorial library of poly(β-amino ester)s and diverse poly(amido amine)s from diamines and diacrylates or bis(acrylamide)s have been reported, respectively. Furthermore, novel linear and hyperbranched polymers from Michael addition polymerizations of trifunctional amines and acrylic monomers significantly enrich this category of biomaterials. In this Review, we focus on the biomaterials from Michael addition polymerizations of trifunctional amines and acrylic monomers. First we discuss how the polymerization mechanisms, which are determined by the reactivity sequence of the three types of amines of trifunctional amines, i.e., secondary (2°) amines (original), primary (1°) amines, and 2° amines (formed), are affected by the chemistry of monomers, reaction temperature, and solvent. Then we update how to design and synthesize linear and hyperbranched polymers based on the understanding of polymerization mechanisms. Linear polymers containing 2° amines in the backbones can be obtained from polymerizations of diacrylates or bis(acrylamide)s with equimolar trifunctional amine, and several approaches, e.g., 2A2+BB'B″, A3+2BB'B', A2+BB'B″, to hyperbranched polymers are developed. Further through molecular design of monomers, conjugation of functional species to 2° amines in the backbones of linear polymers and the abundant terminal groups of hyperbranched polymers, the amphiphilicity of polymers can be adjusted, and additional stimuli, e.g., thermal, redox, reactive oxidation species (ROS), and light, responses can be integrated with the intrinsic pH response. Finally we discuss the applications of the polymers for gene/drug delivery and bioimaging through exploring their self-assemblies in various motifs, e.g., micelles, polyplexes particles/nanorings and hydrogels. Redox-responsive hyperbranched polymers can display 300 times

  19. Allergic contact dermatitis to acrylates in disposable blue diathermy pads.

    Science.gov (United States)

    Sidhu, S K; Shaw, S

    1999-05-01

    We report 2 cases of elicitation of allergic contact dermatitis to acrylates from disposable blue diathermy pads used on patients who underwent routine surgery. Their reactions were severe, and took approximately 5 weeks to resolve. Both patients gave a prior history of finger tip dermatitis following the use of artificial sculptured acrylic nails, which is a common, but poorly reported, cause of acrylate allergy. Patch testing subsequently confirmed allergies to multiple acrylates present in both the conducting gel of disposable blue diathermy pads, and artificial sculptured acrylic nails. We advocate careful history taking prior to surgery to avoid unnecessary exposure to acrylates in patients already sensitized.

  20. Acrylic polymer nanocomposite resins for water borne coating applications

    NARCIS (Netherlands)

    Nobel, M.L.

    2007-01-01

    Due to environmental and safety regulations the use of volatile organic components (VOC's) containing lacquers for exterior automotive purposes is under growing pressure. As a consequence there is a demand for more environmentally friendly alternatives like water borne coatings, high solid coatings,

  1. Acrylic acid surface-modified contact lens for the culture of limbal stem cells.

    Science.gov (United States)

    Zhang, Hong; Brown, Karl David; Lowe, Sue Peng; Liu, Guei-Sheung; Steele, David; Abberton, Keren; Daniell, Mark

    2014-06-01

    Surface treatment to a biomaterial surface has been shown to modify and help cell growth. Our aim was to determine the best surface-modified system for the treatment of limbal stem cell deficiency (LSCD), which would facilitate expansion of autologous limbal epithelial cells, while maintaining cultivated epithelial cells in a less differentiated state. Commercially available contact lenses (CLs) were variously surface modified by plasma polymerization with ratios of acrylic acid to octadiene tested at 100% acrylic acid, 50:50% acrylic acid:octadiene, and 100% octadiene to produce high-, mid-, and no-acid. X-ray photoelectron spectroscopy was used to analyze the chemical composition of the plasma polymer deposited layer. Limbal explants cultured on high acid-modified CLs outgrew more cells. Immunofluorescence and RT2-PCR array results indicated that a higher acrylic acid content can also help maintain progenitor cells during ex vivo expansion of epithelial cells. This study provides the first evidence for the ability of high acid-modified CLs to preserve the stemness and to be used as substrates for the culture of limbal cells in the treatment of LSCD.

  2. Designing temperature-responsive biocompatible copolymers and hydrogels based on 2-hydroxyethyl(meth)acrylates.

    Science.gov (United States)

    Khutoryanskaya, Olga V; Mayeva, Zarina A; Mun, Grigoriy A; Khutoryanskiy, Vitaliy V

    2008-12-01

    Free-radical copolymerization of 2-hydroxyethyl methacrylate with 2-hydroxyethyl acrylate can be successively utilized for the synthesis of water-soluble polymers and hydrogels with excellent physicochemical properties, thus showing promise for pharmaceutical and biomedical applications. In the work presented it has been demonstrated that water-soluble copolymers based on 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate exhibit lower critical solution temperature in aqueous solutions, whereas the corresponding high molecular weight homopolymers do not have this unique property. The temperature-induced transitions observed upon heating the aqueous solutions of these copolymers proceed via liquid-liquid phase separation. The hydrogels were also synthesized by copolymerizing 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate in the absence of a bifunctional cross-linker. The cross-linking of these copolymers during copolymerization is believed to be due to the presence of bifunctional admixtures or transesterification reactions. Transparency, swelling behavior, mechanical properties, and porosity of the hydrogels are dependent upon the monomer ratio in the copolymers. Hydrogel samples containing more 2-hydroxyethyl methacrylate are less transparent, have lower swelling capacity, higher elastic moduli, and pores of smaller size. The assessment of the biocompatibility of the copolymers using the slug mucosal irritation test revealed that they are also less irritant than poly(acrylic acid).

  3. Safety, Healing, and Efficacy of Vascular Prostheses Coated with Hydroxypropyl-[beta]-cyclodextrin Polymer: Experimental In Vitro and Animal Studies

    National Research Council Canada - National Science Library

    Jean-Baptiste, E; Blanchemain, N; Martel, B; Neut, C; Hildebrand, H.F; Haulon, S

    2012-01-01

    Polyester vascular prostheses (PVPs) coated with a polymer of hydroxypropyl-[beta]-cyclodextrin (HP[beta]CD) have been designed to provide an in situ reservoir for the sustained delivery of one or more bioactive molecules...

  4. Safety, healing, and efficacy of vascular prostheses coated with hydroxypropyl-β-cyclodextrin polymer: experimental in vitro and animal studies

    National Research Council Canada - National Science Library

    Jean-Baptiste, E; Blanchemain, N; Martel, B; Neut, C; Hildebrand, H F; Haulon, S

    2012-01-01

    Polyester vascular prostheses (PVPs) coated with a polymer of hydroxypropyl-β-cyclodextrin (HPβCD) have been designed to provide an in situ reservoir for the sustained delivery of one or more bioactive molecules...

  5. An Experimental Study of Polymer Drag Reduction and Boundary Layer Diffusion Characteristics for Incompressible Flow Over a Flat Plate.

    Science.gov (United States)

    1979-08-15

    Macromolecular Solutions," Hendon College of Technology, London, 1966. ___, "Turbulence and Drag Reduction With Polymer Additives," Research Bulletin...no. 4, Hendon College of Technology, London, January 1967. White, F. N., "An Analysis of Flat-Plate Drag With Polymer Additives," Journal of... Christoph , G. H., "A Simple Theory for the Two-Diensional Compressible Turbulent Boundary Layer," Transactions of the ASHE, September 1972. White, F. M

  6. Thiol-vinyl systems as shape memory polymers and novel two-stage reactive polymer systems

    Science.gov (United States)

    Nair, Devatha P.

    2011-12-01

    The focus of this research was to formulate, characterize and tailor the reaction methodologies and material properties of thiol-vinyl systems to develop novel polymer platforms for a range of engineering applications. Thiol-ene photopolymers were demonstrated to exhibit several advantageous characteristics for shape memory polymer systems for a range of biomedical applications. The thiol-ene shape memory polymer systems were tough and flexible as compared to the acrylic control systems with glass transition temperatures between 30 and 40 °C; ideal for actuation at body temperature. The thiol-ene polymers also exhibited excellent shape fixity and a rapid and distinct shape memory actuation response along with free strain recoveries of greater than 96% and constrained stress recoveries of 100%. Additionally, two-stage reactive thiol-acrylate systems were engineered as a polymer platform technology enabling two independent sets of polymer processing and material properties. There are distinct advantages to designing polymer systems that afford two distinct sets of material properties -- an intermediate polymer that would enable optimum handling and processing of the material (stage 1), while maintaining the ability to tune in different, final properties that enable the optimal functioning of the polymeric material (stage 2). To demonstrate the range of applicability of the two-stage reactive systems, three specific applications were demonstrated; shape memory polymers, lithographic impression materials, and optical materials. The thiol-acrylate reactions exhibit a wide range of application versatility due to the range of available thiol and acrylate monomers as well as reaction mechanisms such as Michael Addition reactions and free radical polymerizations. By designing a series of non-stoichiometeric thiol-acrylate systems, a polymer network is initially formed via a base catalyzed 'click' Michael addition reaction. This self-limiting reaction results in a Stage 1

  7. Occupational methacrylate and acrylate allergy from glues.

    Science.gov (United States)

    Aalto-Korte, Kristiina; Alanko, Kristiina; Kuuliala, Outi; Jolanki, Riitta

    2008-06-01

    Glues and sealants are important causes of methacrylate and acrylate allergy. This study aimed to analyse patterns of allergic patch test reactions to acrylic monomers in relation to exposure in patients sensitized from glues. We screened the patch test files at the Finnish Institute of Occupational Health from 1994 to 2006 for allergic reactions in the 'Methacrylate series' and analysed the clinical records of sensitized patients. Only patients who had handled acrylic glues at work were included. 10 patients had allergic reactions to acrylic monomers and had been sensitized from glues at work. 9 of them had used anaerobic sealants, 3 cyanoacrylate-based instant adhesives, and 1 patient a bi-component instant adhesive. All the patients reacted to 2-hydroxyethyl methacrylate (2-HEMA) and ethyleneglycol dimethacrylate (EGDMA); reactions to 2-hydroxypropyl methacrylate, triethyleneglycol dimethacrylate, and tetrahydrofurfuryl methacrylate were also common. The first 4 methacrylates were found in the glues used by the patients. Ethyl cyanoacrylate (ECA) gave no reactions, but 1 patient reacted weakly to her own ECA-based glue. 2-HEMA and EGDMA are good screeners for contact allergy to anaerobic sealants and also detected a single case deriving from bi-component acrylic glue.

  8. Methacrylate and acrylate allergy in dental personnel.

    Science.gov (United States)

    Aalto-Korte, Kristiina; Alanko, Kristiina; Kuuliala, Outi; Jolanki, Riitta

    2007-11-01

    Methacrylates are important allergens in dentistry. The study aimed to analyse patch test reactivity to 36 acrylic monomers in dental personnel in relation to exposure. We reviewed the test files at the Finnish Institute of Occupational Health from 1994 to 2006 for allergic reactions to acrylic monomers in dental personnel and analysed the clinical records of the sensitized patients. 32 patients had allergic reactions to acrylic monomers: 15 dental nurses, 9 dentists, and 8 dental technicians. The dentists and dental nurses were most commonly exposed to 2-hydroxyethyl methacrylate (2-HEMA), triethyleneglycol dimethacrylate (TREGDMA), and 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (bis-GMA). 8 dentists and 12 dental nurses were allergic to 2-HEMA. The remaining dentist was positive to bis-GMA and other epoxy acrylates. The remaining 3 dental nurses reacted to diethyleneglycol diacrylate (DEGDA) or triethyleneglycol diacrylate (TREGDA), but not to monofunctional and multifunctional methacrylates. Our dental technicians were mainly exposed and sensitized to methyl methacrylate (MMA) and ethyleneglycol dimethacrylate (EGDMA). 1 technician reacted only to 2-HEMA, and another to ethyl methacrylate (EMA) and ethyl acrylate (EA). 2-HEMA was the most important allergen in dentists and dental nurses, and MMA and EGDMA in dental technicians. Reactions to bis-GMA, DEGDA, TREGDA, EMA and EA were relevant in some patients.

  9. Rational design of core-shell molecularly imprinted polymer based on computational simulation and Doehlert experimental optimization: application to the separation of tanshinone IIA from Salvia miltiorrhiza Bunge.

    Science.gov (United States)

    Jia, Xianjun; Li, Hong; Luo, Jing; Lu, Qing; Peng, Yan; Shi, Liying; Liu, Liping; Du, Shuhu; Zhang, Guijun; Chen, Lina

    2012-07-01

    Computational simulation and Doehlert experimental optimization were done for the rational design of a core-shell molecularly imprinted polymer (CS-MIP) for use in the highly selective separation of Tanshinone IIA (TSIIA) from the crude extracts of Salvia miltiorrhiza Bunge (SMB). The functional monomer layer of the polymer shells directed the selective occurrence of imprinting polymerization at the surface of silica through the copolymerization of vinyl end groups with functional monomers and also drove TSIIA templates into the formed polymer shells through the charge-transfer complex interactions between TSIIA and the functional monomer layer. As a result, the maximum rebinding capacity was achieved with the use of optimal grafting ratio by the Doehlert design. The CS-MIP exhibited high recognition selectivity and binding affinity to TSIIA. When the imprinted particles were used as dispersive solid phase extraction sorbents, the recovery yield of TSIIA reached 93% by a one-step extraction from the crude extracts of SMB, and the purity of TSIIA was larger than 98% by HPLC analysis. These results show the possibility of a highly selective separation and enrichment of TSIIA from the SMB using the TSIIA-imprinted core-shell molecularly imprinted polymers.

  10. Experimental and theoretical studies of xanthan gum and its graft co-polymer as corrosion inhibitor for mild steel in 15% HCl

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Amrita; Pal, Sagar; Udayabhanu, G., E-mail: g_udayabhanu@hotmail.com

    2015-10-30

    Highlights: • Xanthan gum and its graft co-polymer used as corrosion inhibitors for mild steel in 15% HCl. • Electrochemical and weight loss studies give comparable corrosion rates. • Both the inhibitors are mixed type in nature. • Modified graft co-polymer is a more effective corrosion inhibitor. • Theoretical calculations taking monomer units of the polymer support the experimental results. - Abstract: Xanthan gum (XG) and its graft co-polymer have been investigated as corrosion inhibitors for mild steel in 15% HCl. Gravimetric analysis, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods were employed for investigating the effectiveness of these inhibitors. Results indicate that both the inhibitors are of mixed type and follow Langmuir adsorption isotherm. Scanning electron microscopy (SEM) study also confirmed the protection of the metal surface by XG and xanthan gum-graft-poly(acrylamide) (XG-g-PAM). Theoretical calculations using Density Functional Theory (DFT) were used to establish the correlation between the structure and corrosion protection efficiencies.

  11. In Vitro Antifungal Evaluation of Seven Different Disinfectants on Acrylic Resins

    Directory of Open Access Journals (Sweden)

    A. Z. Yildirim-Bicer

    2014-01-01

    Full Text Available Objective. The aim of this study was to evaluate alternative methods for the disinfection of denture-based materials. Material and Methods. Two different denture-based materials were included in the study. Before microbial test, the surface roughness of the acrylic resins was evaluated. Then, the specimens were divided into 8 experimental groups (n=10, according to microorganism considered and disinfection methods used. The specimens were contaminated in vitro by standardized suspensions of Candida albicans ATCC#90028 and Candida albicans oral isolate. The following test agents were tested: sodium hypochlorite (NaOCl 1%, microwave (MW energy, ultraviolet (UV light, mouthwash containing propolis (MCP, Corega Tabs, 50% and 100% white vinegar. After the disinfection procedure, the number of remaining microbial cells was evaluated in CFU/mL. Kruskal-Wallis, ANOVA, and Dunn’s test were used for multiple comparisons. Mann Whitney U test was used to compare the surface roughness. Results. Statistically significant difference (P<0.05 was found between autopolymerised and heat-cured acrylic resins. The autopolymerised acrylic resin surfaces were rougher than surfaces of heat-cured acrylic resin. The most effective disinfection method was 100% white vinegar for tested microorganisms and both acrylic resins. Conclusion. This study showed that white vinegar 100% was the most effective method for tested microorganisms. This agent is cost-effective and easy to access and thus may be appropriate for household use.

  12. In vitro antifungal evaluation of seven different disinfectants on acrylic resins.

    Science.gov (United States)

    Yildirim-Bicer, A Z; Peker, I; Akca, G; Celik, I

    2014-01-01

    The aim of this study was to evaluate alternative methods for the disinfection of denture-based materials. Two different denture-based materials were included in the study. Before microbial test, the surface roughness of the acrylic resins was evaluated. Then, the specimens were divided into 8 experimental groups (n = 10), according to microorganism considered and disinfection methods used. The specimens were contaminated in vitro by standardized suspensions of Candida albicans ATCC#90028 and Candida albicans oral isolate. The following test agents were tested: sodium hypochlorite (NaOCl 1%), microwave (MW) energy, ultraviolet (UV) light, mouthwash containing propolis (MCP), Corega Tabs, 50% and 100% white vinegar. After the disinfection procedure, the number of remaining microbial cells was evaluated in CFU/mL. Kruskal-Wallis, ANOVA, and Dunn's test were used for multiple comparisons. Mann Whitney U test was used to compare the surface roughness. Statistically significant difference (P acrylic resins. The autopolymerised acrylic resin surfaces were rougher than surfaces of heat-cured acrylic resin. The most effective disinfection method was 100% white vinegar for tested microorganisms and both acrylic resins. This study showed that white vinegar 100% was the most effective method for tested microorganisms. This agent is cost-effective and easy to access and thus may be appropriate for household use.

  13. Evaluation of Liquid-Liquid Extraction Process for Separating Acrylic Acid Produced From Renewable Sugars

    Science.gov (United States)

    Alvarez, M. E. T.; Moraes, E. B.; Machado, A. B.; Maciel Filho, R.; Wolf-Maciel, M. R.

    In this article, the separation and the purification of the acrylic acid produced from renewable sugars were studied using the liquid-liquid extraction process. Nonrandom two-liquids and universal quasi-chemical models and the prediction method univeral quasi-chemical functional activity coefficients were used for generating liquid-liquid equilibrium diagrams for systems made up of acrylic acid, water, and solvents (diisopropyl ether, isopropyl acetate, 2-ethyl hexanol, and methyl isobutyl ketone) and the results were compared with available liquid-liquid equilibrium experimental data. Aspen Plus (Aspen Technology, Inc., version 2004.1) software was used for equilibrium and process calculations. High concentration of acrylic acid was obtained in this article using diisopropyl ether as solvent.

  14. Kekuatan transversa resin akrilik hybrid setelah penambahan glass fiber dengan metode berbeda (The transverse strength of the hybrid acrylic resin after glass fiber reinforcement with different method

    Directory of Open Access Journals (Sweden)

    Intan Nirwana

    2006-03-01

    Full Text Available Different types of fibers have been added to acrylic resin materials to improve their mechanical properties. The purpose of this study was to know the transverse strength of the hybrid acrylic resins after glass fiber reinforcement with difference method. This study used rectangular specimens of 65 mm in length, 10 mm in width and 2.5 mm in thickness. There were 3 groups consisting of 6 specimens each, hybrid acrylic resin without glass fiber (control, glass fibers dipped in methyl methacrylate monomer for 15 minutes before being reinforced into hybrid acrylic resin (first method, glass fibers reinforced into a mixture of polymer powder and monomer liquid after the hybrid acrylic resin was mixed directly (second method. All of the specimens were cured for 20 minutes at 100° C. Transverse strength was measured using Autograph. The statistical analyses using one way ANOVA and LSD test showed that there were significant differences in transverse strength (p < 0.05 among the groups. The means of transverse strength were 94,94; 118,27; and 116,34 MPa. It meant that glass fibers reinforcement into hybrid acrylic resin enhanced their transverse strength compared with control. Glass fiber reinforcement into hybrid acrylic resin with differenciate method didn’t enhance their transverse strength.

  15. Polymer modification of bitumen : Advances and challenges

    OpenAIRE

    Zhu, Jiqing; Birgisson, Björn; Kringos, Niki

    2014-01-01

    Advances and challenges in the field of bitumen polymer modification for road construction during the last 40 years are reviewed in this paper. The history of bitumen polymer modification is described chronologically. Some popular plastomers and thermoplastic elastomers in bitumen modification are discussed regarding their advantages and disadvantages, including polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate (EVA), ethylene-butyl acrylate (EBA), styrene-butadiene-styrene (SBS),...

  16. UV-Curable Aliphatic Silicone Acrylate Organic-Inorganic Hybrid Coatings with Antibacterial Activity.

    Science.gov (United States)

    Jankauskaitė, Virginija; Lazauskas, Algirdas; Griškonis, Egidijus; Lisauskaitė, Aistė; Žukienė, Kristina

    2017-06-09

    The most effective means to protect against bacterial invasion and to reduce the risk of healthcare-associated infections are antibacterial components synthesis. In this study, a novel process for the synthesis of organic-inorganic hybrid coatings containing silver nanoparticles is presented. Silver nanoparticles and polymer formation proceeds simultaneously through the in situ photoreduction of silver salt to silver nanoparticles and UV-crosslinking of bifunctional aliphatic silicone acrylate. The nanocomposite films with 0.5-1.43 wt % of silver nanoparticles concentration were obtained and investigated. The formation of silver nanoparticles in polymer matrix was confirmed via UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron spectroscopy, and energy dispersive spectroscopy. Our investigations clearly show the formation of silver nanoparticles in silicone acrylate network. Direct photoreduction of silver salt by UV-radiation in the organic media produced silver nanoparticles exhibiting cubic crystal structure. The size of nanoparticles was determined to be near 20 ± 5 nm. The antibacterial activities of coatings were determined using the disc diffusion and direct contact methods. UV-curable silicone acrylate hybrid coatings exhibited antibacterial activity against harmful bacteria strains.

  17. All-acrylic superelastomers: facile synthesis and exceptional mechanical behavior

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei [Department of Chemistry; University of Tennessee; Knoxville; USA; Goodwin, Andrew [Department of Chemistry; University of Tennessee; Knoxville; USA; Wang, Yangyang [Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge; USA; Yin, Panchao [Chemical and Engineering Materials Division; Oak Ridge National Laboratory; Oak Ridge; USA; Wang, Weiyu [Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge; USA; Zhu, Jiahua [Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge; USA; Wu, Ting [Department of Materials Science and Engineering; University of Tennessee; Knoxville; USA; Lu, Xinyi [Department of Chemistry; University of Tennessee; Knoxville; USA; Hu, Bin [Department of Materials Science and Engineering; University of Tennessee; Knoxville; USA; Hong, Kunlun [Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge; USA; Kang, Nam-Goo [Department of Chemistry; University of Tennessee; Knoxville; USA; Mays, Jimmy [Department of Chemistry; University of Tennessee; Knoxville; USA

    2018-01-01

    All-acrylic multigraft copolymers made by a facile synthesis procedure exhibit elongation at break >1700% and strain recovery behavior far exceeding those of commercial acrylic and styrenic triblock copolymers.

  18. High acrylate concentrations in the mucus of Phaeocystis globosa colonies

    NARCIS (Netherlands)

    Noordkamp, D.J B; Schotten, M; Gieskes, W.W C; Forney, L.J; Gottschal, J.C; van Rijssel, M

    1998-01-01

    Acrylate produced from dimethylsulphoniopropionate (DMSP) by Phaeocystis has been claimed to inhibit bacterial growth. However, the concentrations of acrylate measured in seawater during Phaeocystis blooms are not high enough to expect inhibition of bacterial growth. In this study, the total

  19. High-impact strength acrylic denture base material processed by autoclave.

    Science.gov (United States)

    Abdulwahhab, Salwan Sami

    2013-10-01

    To investigate the effect of two different cycles of autoclave processing on the transverse strength, impact strength, surface hardness and the porosity of high-impact strength acrylic denture base material. High Impact Acryl was the heat-cured acrylic denture base material included in the study. A total of 120 specimens were prepared, the specimens were grouped into: control groups in which high-impact strength acrylic resins processed by conventional water-bath processing technique (74°C for 1.5 h then boil for 30 min) and experimental groups in which high-impact strength acrylic resins processed by autoclave at 121°C, 210 kPa .The experimental groups were divided into (fast) groups for 15 min, and (slow) groups for 30 min. To study the effect of the autoclave processing (Tuttnauer 2540EA), four tests were conducted transverse strength (Instron universal testing machine), impact strength (Charpy tester), surface hardness (shore D), and porosity test. The results were analyzed to ANOVA and LSD test. In ANOVA test, there were highly significant differences between the results of the processing techniques in transverse, impact, hardness, and porosity test. The LSD test showed a significant difference between control and fast groups in transverse and hardness tests and a non-significant difference in impact test and a highly significant difference in porosity test; while, there were a highly significant differences between control and slow groups in all examined tests; finally, there were a non-significant difference between fast and slow groups in transverse and porosity tests and a highly significant difference in impact and hardness tests. In the autoclave processing technique, the slow (long) curing cycle improved the tested physical and mechanical properties as compared with the fast (short) curing cycle. The autoclave processing technique improved the tested physical and mechanical properties of High Impact Acryl. Copyright © 2013 Japan Prosthodontic Society

  20. Synthesis and characterization of core-shell acrylate based latex and study of its reactive blends.

    Science.gov (United States)

    Liu, Xiang; Fan, Xiao-Dong; Tang, Min-Feng; Nie, Ying

    2008-03-01

    Techniques in resin blending are simple and efficient method for improving the properties of polymers, and have been used widely in polymer modification field. However, polymer latex blends such as the combination of latexes, especially the latexes with water-soluble polymers, were rarely reported. Here, we report a core-shell composite latex synthesized using methyl methacrylate (MMA), butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) and glycidyl methacrylate (GMA) as monomers and ammonium persulfate and sodium bisulfite redox system as the initiator. Two stages seeded semi-continuous emulsion polymerization were employed for constructing a core-shell structure with P(MMA-co-BA) component as the core and P(EHA-co-GMA) component as the shell. Results of Transmission Electron Microscopy (TEM) and Dynamics Light Scattering (DLS) tests confirmed that the particles obtained are indeed possessing a desired core-shell structural character. Stable reactive latex blends were prepared by adding the latex with waterborne melamine-formaldehyde resin (MF) or urea-formaldehyde resin (UF). It was found that the glass transition temperature, the mechanical strength and the hygroscopic property of films cast from the latex blends present marked enhancements under higher thermal treatment temperature. It was revealed that the physical properties of chemically reactive latexes with core-shell structure could be altered via the change of crosslinking density both from the addition of crosslinkers and the thermal treatment.

  1. Synthesis and Characterization of Core-Shell Acrylate Based Latex and Study of Its Reactive Blends

    Directory of Open Access Journals (Sweden)

    Ying Nie

    2008-03-01

    Full Text Available Techniques in resin blending are simple and efficient method for improving the properties of polymers, and have been used widely in polymer modification field. However, polymer latex blends such as the combination of latexes, especially the latexes with water-soluble polymers, were rarely reported. Here, we report a core-shell composite latex synthesized using methyl methacrylate (MMA, butyl acrylate (BA, 2-ethylhexyl acrylate (EHA and glycidyl methacrylate (GMA as monomers and ammonium persulfate and sodium bisulfite redox system as the initiator. Two stages seeded semi-continuous emulsion polymerization were employed for constructing a core-shell structure with P(MMA-co-BA component as the core and P(EHA-co-GMA component as the shell. Results of Transmission Electron Microscopy (TEM and Dynamics Light Scattering (DLS tests confirmed that the particles obtained are indeed possessing a desired core-shell structural character. Stable reactive latex blends were prepared by adding the latex with waterborne melamine-formaldehyde resin (MF or urea-formaldehyde resin (UF. It was found that the glass transition temperature, the mechanical strength and the hygroscopic property of films cast from the latex blends present marked enhancements under higher thermal treatment temperature. It was revealed that the physical properties of chemically reactive latexes with core-shell structure could be altered via the change of crosslinking density both from the addition of crosslinkers and the thermal treatment.

  2. Concepts for stereoselective acrylate insertion

    KAUST Repository

    Neuwald, Boris

    2013-01-23

    Various phosphinesulfonato ligands and the corresponding palladium complexes [{((PaO)PdMeCl)-μ-M}n] ([{( X1-Cl)-μ-M}n], (PaO) = κ2- P,O-Ar2PC6H4SO2O) with symmetric (Ar = 2-MeOC6H4, 2-CF3C6H4, 2,6-(MeO)2C6H3, 2,6-(iPrO)2C 6H3, 2-(2′,6′-(MeO)2C 6H3)C6H4) and asymmetric substituted phosphorus atoms (Ar1 = 2,6-(MeO)2C6H 3, Ar2 = 2′-(2,6-(MeO)2C 6H3)C6H4; Ar1 = 2,6-(MeO)2C6H3, Ar2 = 2-cHexOC 6H4) were synthesized. Analyses of molecular motions and dynamics by variable temperature NMR studies and line shape analysis were performed for the free ligands and the complexes. The highest barriers of ΔGa = 44-64 kJ/mol were assigned to an aryl rotation process, and the flexibility of the ligand framework was found to be a key obstacle to a more effective stereocontrol. An increase of steric bulk at the aryl substituents raises the motional barriers but diminishes insertion rates and regioselectivity. The stereoselectivity of the first and the second methyl acrylate (MA) insertion into the Pd-Me bond of in situ generated complexes X1 was investigated by NMR and DFT methods. The substitution pattern of the ligand clearly affects the first MA insertion, resulting in a stereoselectivity of up to 6:1 for complexes with an asymmetric substituted phosphorus. In the consecutive insertion, the stereoselectivity is diminished in all cases. DFT analysis of the corresponding insertion transition states revealed that a selectivity for the first insertion with asymmetric (P aO) complexes is diminished in the consecutive insertions due to uncooperatively working enantiomorphic and chain end stereocontrol. From these observations, further concepts are developed. © 2012 American Chemical Society.

  3. Transformation of Metal-Organic Frameworks/Coordination Polymers into Functional Nanostructured Materials: Experimental Approaches Based on Mechanistic Insights.

    Science.gov (United States)

    Lee, Kyung Joo; Lee, Jae Hwa; Jeoung, Sungeun; Moon, Hoi Ri

    2017-10-09

    Nanostructured materials such as porous metal oxides, metal nanoparticles, porous carbons, and their composites have been intensively studied due to their applications, including energy conversion and storage devices, catalysis, and gas storage. Appropriate precursors and synthetic methods are chosen for synthesizing the target materials. About a decade ago, metal-organic frameworks (MOFs) and coordination polymers (CPs) emerged as new precursors for these nanomaterials because they contain both organic and inorganic species that can play parallel roles as both a template and a precursor under given circumstances. Thermal conversions of MOFs offer a promising toolbox for synthesizing functional nanomaterials that are difficult to obtain using conventional methods. Although understanding the conversion mechanism is important for designing MOF precursors for the synthesis of nanomaterials with desired physicochemical properties, comprehensive discussions revealing the transformation mechanism remain insufficient. This Account reviews the utilization of MOFs/CPs as precursors and their transformation into functional nanomaterials with a special emphasis on understanding the relationship between the intrinsic nature of the parent MOFs and the daughter nanomaterials while discussing various experimental approaches based on mechanistic insights. We discuss nanomaterials categorized by materials such as metal-based nanomaterials and porous carbons. For metal-based nanomaterials transformed from MOFs, the nature of metal ions in the MOF scaffolds affects the physicochemical properties of the resultant materials including the phase, composite, and morphology of nanomaterials. Organic ligands are also involved in the in situ chemical reactions with metal species during thermal conversion. We describe these conversion mechanisms by classifying the phase of metal components in the resultant materials. Along with the metal species, carbon is a major element in MOFs, and thus

  4. In-depth disinfection of acrylic resins.

    Science.gov (United States)

    Chau, V B; Saunders, T R; Pimsler, M; Elfring, D R

    1995-09-01

    This study demonstrated that bacteria penetrate three kinds of dental acrylic resin after a short time period. Samples of acrylic resin were contaminated with a variety of bacteria and were then placed in three different disinfecting solutions as directed by the manufacturers. After the specific dilution and immersion time, cultures were made from the resin samples. The only effective disinfectant was a 0.525% solution of sodium hypochlorite at a 10-minute immersion. It disinfected not only the surfaces but also the bacteria that penetrated the surfaces to a depth of 3 mm.

  5. Allergic contact dermatitis to acrylates in disposable blue diathermy pads.

    OpenAIRE

    Sidhu, S K; Shaw, S.

    1999-01-01

    We report 2 cases of elicitation of allergic contact dermatitis to acrylates from disposable blue diathermy pads used on patients who underwent routine surgery. Their reactions were severe, and took approximately 5 weeks to resolve. Both patients gave a prior history of finger tip dermatitis following the use of artificial sculptured acrylic nails, which is a common, but poorly reported, cause of acrylate allergy. Patch testing subsequently confirmed allergies to multiple acrylates present in...

  6. Multiscale characterization of chemical–mechanical interactions between polymer fibers and cementitious matrix

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-Cruz, Daniel; Hargis, Craig W.; Bae, Sungchul; Itty, Pierre A.; Meral, Cagla; Dominowski, Jolee; Radler, Michael J.; Kilcoyne, David A.; Monteiro, Paulo J. M.

    2014-04-01

    Together with a series of mechanical tests, the interactions and potential bonding between polymeric fibers and cementitious materials were studied using scanning transmission X-ray microscopy (STXM) and microtomography (lCT). Experimental results showed that these techniques have great potential to characterize the polymer fiber-hydrated cement-paste matrix interface, as well as differentiating the chemistry of the two components of a bi-polymer (hybrid) fiber the polypropylene core and the ethylene acrylic acid copolymer sheath. Similarly, chemical interactions between the hybrid fiber and the cement hydration products were observed, indicating the chemical bonding between the sheath and the hardened cement paste matrix. Microtomography allowed visualization of the performance of the samples, and the distribution and orientation of the two types of fiber in mortar. Beam flexure tests confirmed improved tensile strength of mixes containing hybrid fibers, and expansion bar tests showed similar reductions in expansion for the polypropylene and hybrid fiber mortar bars.

  7. 40 CFR 721.8082 - Polyester polyurethane acrylate.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyester polyurethane acrylate. 721... Substances § 721.8082 Polyester polyurethane acrylate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as polyester polyurethane acrylate...

  8. Allergic contact dermatitis due to an epoxy acrylate.

    Science.gov (United States)

    Nethercott, J R

    1981-06-01

    A printer developed allergic contact dermatitis due to epoxy acrylate resin. Incomplete cross-reactivity between four epoxy acrylate resins and a lack of cross-reactivity to epoxy resin was demonstrated. The epoxy acrylate resin has been shown to be a potent cutaneous sensitizer for the guinea-pig.

  9. 40 CFR 721.4794 - Polypiperidinol-acrylate methacrylate.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polypiperidinol-acrylate methacrylate... Substances § 721.4794 Polypiperidinol-acrylate methacrylate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as polypiperidinol-acrylate...

  10. 40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated benzyl ester acrylate... Specific Chemical Substances § 721.329 Halogenated benzyl ester acrylate (generic). (a) Chemical substance... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for the...

  11. 40 CFR 721.10081 - Aromatic urethane acrylate oligomer (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic urethane acrylate oligomer... Specific Chemical Substances § 721.10081 Aromatic urethane acrylate oligomer (generic). (a) Chemical... as aromatic urethane acrylate oligomer (PMN P-06-26) is subject to reporting under this section for...

  12. 40 CFR 721.5325 - Nickel acrylate complex.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Nickel acrylate complex. 721.5325... Substances § 721.5325 Nickel acrylate complex. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance nickel acrylate complex (PMN P-85-1034) is subject to reporting under...

  13. 21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-ethyl acrylate copolymers. 177.1320... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1320 Ethylene-ethyl acrylate copolymers. Ethylene-ethyl acrylate copolymers may be safely used to produce packaging materials, containers...

  14. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be safely...

  15. 21 CFR 573.120 - Acrylamide-acrylic acid resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573.120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin...

  16. 21 CFR 176.110 - Acrylamide-acrylic acid resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylamide-acrylic acid resins. 176.110 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.110 Acrylamide-acrylic acid resins. Acrylamide-acrylic acid resins may be safely used as components of articles intended for use in producing...

  17. Amylase catalyzed synthesis of glycosyl acrylates and their polymerization

    NARCIS (Netherlands)

    Kloosterman, Wouter M.J.; Jovanovic, Danijela; Brouwer, Sander; Loos, Katja

    2014-01-01

    The enzymatic synthesis of novel (di)saccharide acrylates from starch and 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 4-hydroxybutyl acrylate (2-HEA, 2-HEMA and 4-HBA) catalyzed by various commercially available amylase preparations is demonstrated. Both liquefaction and

  18. Experimental degradation of polymer shopping bags (standard and degradable plastic, and biodegradable) in the gastrointestinal fluids of sea turtles.

    Science.gov (United States)

    Müller, Christin; Townsend, Kathy; Matschullat, Jörg

    2012-02-01

    The persistence of marine debris such as discarded polymer bags has become globally an increasing hazard to marine life. To date, over 177 marine species have been recorded to ingest man-made polymers that cause life-threatening complications such as gut impaction and perforation. This study set out to test the decay characteristics of three common types of shopping bag polymers in sea turtle gastrointestinal fluids (GIF): standard and degradable plastic, and biodegradable. Fluids were obtained from the stomachs, small intestines and large intestines of a freshly dead Green turtle (Chelonia mydas) and a Loggerhead turtle (Caretta caretta). Controls were carried out with salt and freshwater. The degradation rate was measured over 49 days, based on mass loss. Degradation rates of the standard and the degradable plastic bags after 49 days across all treatments and controls were negligible. The biodegradable bags showed mass losses between 3 and 9%. This was a much slower rate than reported by the manufacturers in an industrial composting situation (100% in 49 days). The GIF of the herbivorous Green turtle showed an increased capacity to break down the biodegradable polymer relative to the carnivorous Loggerhead, but at a much lower rate than digestion of natural vegetative matter. While the breakdown rate of biodegradable polymers in the intestinal fluids of sea turtles is greater than standard and degradable plastics, it is proposed that this is not rapid enough to prevent morbidity. Further study is recommended to investigate the speed at which biodegradable polymers decompose outside of industrial composting situations, and their durability in marine and freshwater systems. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Features and management of an acute allergic response to acrylic ocular prostheses.

    Science.gov (United States)

    Patel, Vikesh; Allen, David; Morley, Ana M S; Frcophth, Raman Malhotra

    2009-01-01

    To report the occurrence, causes and treatment of an acute allergic response to the acrylic resin used in ocular prostheses. Retrospective review of presenting history, clinical findings and treatment of two cases. Both patients developed an acute onset hypersensitivity reaction thought to be due to the acrylic resin found in the ocular prosthesis. The first patient was successfully switched to a glass eye. The prosthesis of the second patient was treated with an extra long curing cycle, after which, the patient was able to tolerate their prosthesis with no complications. The residual unpolymerized monomer that is present within poly-methylmethacrylate (PMMA) can rarely cause an allergic reaction. As an alternative to a glass eye the prosthesis may be subjected to an extended curing cycle converting more of the monomer to polymer.

  20. Peel/seal properties of poly(ethylene methyl acrylate)/polybutene-1 blend films

    Energy Technology Data Exchange (ETDEWEB)

    Mohammdi, Seyedeh Raziyeh; Ajji, Abdellah; Tabatabaei, Seyed H. [Department of Chemical Engineering, École Polytechnique de Montréal, Montréal, Québec, H3C3A7 (Canada)

    2015-05-22

    Nowadays, the possibility to easy open a food package is of great interest both from the consumer and food producers’ perspective. In this study, the peel/seal properties of poly (ethylene methyl acrylate) (EMA)/polybutene-1 (PB-1) blend films were investigated. Three blends of EMA/PB-1 with different methyl acrylate (MA) content were prepared using cast extrusion process. Differential Scanning Calorimetry (DSC) was used to investigate the thermal behavior as well as the crystalinity of the blends. The effect of polymer matrix on the crystalline structure of PB-1 was studied using Wide Angle X-ray Diffraction (WAXD) and DSC. T-peel tests were carried out on the heat sealed films at various seal temperatures. The effect of MA content and heat seal temperature on peel/seal properties (i.e. peel initiation temperature, temperature window of sealability and peel strength) of the films were studied.

  1. Surface and Curing Properties of Oriental Lacquer Modified by Acryl Monomer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Kyoung; Park, Mee Young; Hong, Jin Who [Department of Polymer Science and Engineering, Chosun University, Kwangju (Korea); Yu, Jeong A [School of Science Education, Chemical Major, Chosun University, Kwangju (Korea)

    2001-06-01

    UV-curable acryl monomer containing a quarternary ammonium salt was introduced to an oriental lacquer by a dual curing method. Curing behavior of the oriental lacquers containing different amount (5, 10, 15, 20 wt%) of acryl monomer was characterized using a real-time FT-IR. Commonly, film of the oriental lacquer is cured by the oxidative reaction of laccase enzyme. The result showed that the dual curing, the enzymatic reaction and UV treatment, of the modified oriental lacquer containing the quartary ammonium salt promoted the formation of interpenetrating polymer networks (IPN). It is also shown that the modified oriental lacquer containing 10 wt% of the quartary ammonium salt, introduced anti-static properties into the coating networks, although its surface hardness was somewhat reduced. 15 refs., 9 figs., 2 tabs.

  2. Synthesis and properties of hydroxy acrylic resin with high solid content

    Science.gov (United States)

    Yu, Zhen; Hu, Mingguang; Cui, Han; Xiao, Jijun

    2017-10-01

    Manufacturers of automotive repair finishes are tending to reduce more and more the level of volatile organic compounds in their paints in order to comply with increasingly strict environmental legislation. A high solid hydroxy acrylic resin was synthesised using CARDURA E10 and a type of hydroxyacrylic acid resin, its' acid value, hydroxylvalue, viscosity, structure, morphology was measured and film-forming properties after curing were characterised. The results show that the addition of CARDURA E10 in the copolymer composition significantly reduced the viscosity of the polymer system, improved the solid content of the resin and the physical properties of the coating. The hydroxyl acrylate resin with solid content of 90% and excellent comprehensive performance were successfully prepared by controlling the initiator dosage, polymerization temperature and monomer ratio.

  3. Polymer nitric oxide donors potentiate the treatment of experimental solid tumours by increasing drug accumulation in the tumour tissue

    Czech Academy of Sciences Publication Activity Database

    Studenovský, Martin; Sivák, Ladislav; Sedláček, Ondřej; Konefal, Rafal; Horková, Veronika; Etrych, Tomáš; Kovář, Marek; Říhová, Blanka; Šírová, Milada

    2018-01-01

    Roč. 269, 10 January (2018), s. 214-224 ISSN 0168-3659 R&D Projects: GA ČR(CZ) GA14-12742S; GA MZd(CZ) NV16-28600A; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : enhanced permeability and retention effect * nitric oxide donor * polymer-based cytotoxic drugs Subject RIV: CD - Macromolecular Chemistry; EB - Genetics ; Molecular Biology (MBU-M) OBOR OECD: Polymer science; Biochemical research methods (MBU-M) Impact factor: 7.786, year: 2016

  4. In Situ Synthesis of Reduced Graphene Oxide-Reinforced Silicone-Acrylate Resin Composite Films Applied in Erosion Resistance

    Directory of Open Access Journals (Sweden)

    Yang Cao

    2015-01-01

    Full Text Available The reduced graphene oxide reinforced silicone-acrylate resin composite films (rGO/SAR composite films were prepared by in situ synthesis method. The structure of rGO/SAR composite films was characterized by Raman spectrum, atomic force microscope, scanning electron microscopy, and thermogravimetric analyzer. The results showed that the rGO were uniformly dispersed in silicone-acrylate resin matrix. Furthermore, the effect of rGO loading on mechanical properties of composite films was investigated by bulge test. A significant enhancement (ca. 290% and 320% in Young’s modulus and yield stress was obtained by adding the rGO to silicone-acrylate resin. At the same time, the adhesive energy between the composite films and metal substrate was also improved to be about 200%. Moreover, the erosion resistance of the composite films was also investigated as function of rGO loading. The rGO had great effect on the erosion resistance of the composite films, in which the Rcorr (ca. 0.8 mm/year of composite film was far lower than that (28.7 mm/year of pure silicone-acrylate resin film. Thus, this approach provides a novel route to investigate mechanical stability of polymer composite films and improve erosion resistance of polymer coating, which are very important to be used in mechanical-corrosion coupling environments.

  5. TISSUE AND CELL REACTION OF THE SYNOVIAL MEDIA TO INTRAARTICULAR INJECTION OF POLYMER VISCOPROSTHESIS “NOLTREX” IN EXPERIMENTAL CONDITIONS

    Directory of Open Access Journals (Sweden)

    A. B. Shekhter

    2013-01-01

    Full Text Available Reaction of synovial membrane and cartilage on 1 ml of polymer gel «NOLTREX» injected into the cavity of jumping joint of 20 rabbits was investigated. Biological inertness and safety of noltrex injected into the joint cavity was established.

  6. 40 CFR 721.405 - Polyether acrylate.

    Science.gov (United States)

    2010-07-01

    ... 721.405 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL...) The chemical substance identified generically as a polyether acrylate (PMN P-95-666) is subject to... this section except as modified by this paragraph. (1) Recordkeeping. Recordkeeping requirements as...

  7. Self-replenishing ability of cross-linked low surface energy polymer films investigated by a complementary experimental-simulation approach

    Energy Technology Data Exchange (ETDEWEB)

    Esteves, A. C. C., E-mail: a.c.c.esteves@tue.nl, E-mail: g.dewith@tue.nl; Lyakhova, K.; Riel, J. M. van; With, G. de, E-mail: a.c.c.esteves@tue.nl, E-mail: g.dewith@tue.nl [Laboratory of Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven (Netherlands); Ven, L. G. J. van der [Laboratory of Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven (Netherlands); AkzoNobel, Automotive and Aerospace Coatings, Sassenheim (Netherlands); Benthem, R. A. T. M. van [Laboratory of Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven (Netherlands); DSM Ahead, Geleen (Netherlands)

    2014-03-28

    Nowadays, many self-healing strategies are available for recovering mechanical damage of bulk polymeric materials. The recovery of surface-dependent functionalities on polymer films is, however, equally important and has been less investigated. In this work we study the ability of low surface energy cross-linked poly(ester urethane) networks containing perfluorinated dangling chains to self-replenish their surface, after being submitted to repeated surface damage. For this purpose we used a combined experimental-simulation approach. Experimentally, the cross-linked films were intentionally damaged by cryo-microtoming to remove top layers and create new surfaces which were characterized by water Contact Angle measurements and X-Ray Photoelectron Spectroscopy. The same systems were simultaneously represented by a Dissipative Particles Dynamics simulation method, where the damage was modeled by removing the top film layers in the simulation box and replacing it by new “air” beads. The influence of different experimental parameters, such as the concentration of the low surface energy component and the molecular mobility span of the dangling chains, on the surface recovery is discussed. The combined approach reveals important details of the self-replenishing ability of damaged polymer films such as the occurrence of multiple-healing events, the self-replenishing efficiency, and the minimum “healing agent” concentration for a maximum recovery.

  8. Surface energy-tunable iso decyl acrylate based molds for low pressure-nanoimprint lithography

    Science.gov (United States)

    Tak, Hyowon; Tahk, Dongha; Jeong, Chanho; Lee, Sori; Kim, Tae-il

    2017-10-01

    We presented surface energy-tunable nanoscale molds for unconventional lithography. The mold is highly robust, transparent, has a minimized haze, does not contain additives, and is a non-fluorinated isodecyl acrylate and trimethylolpropane triacrylate based polymer. By changing the mixing ratio of the polymer components, the cross-linking density, mechanical modulus, and surface energy (crucial factors in low pressure ((1-2) × 105 N m-2) low pressure-nanoimprint lithography (LP-NIL)), can be controlled. To verify these properties of the molds, we also characterized the surface energy by measuring the contact angles and calculating the work of adhesion among the wafer, polymer film, and mold for successful demolding in nanoscale structures. Moreover, the molds showed high optical clarity and precisely tunable mechanical and surface properties, capable of replicating sub-100 nm patterns by thermal LP-NIL and UV-NIL.

  9. (Liquid + liquid) equilibria of binary systems containing hyperbranched polymer Boltorn (registered) H2004 - Experimental study and modelling in terms of lattice-cluster theory

    Energy Technology Data Exchange (ETDEWEB)

    Domanska, Urszula, E-mail: ula@ch.pw.edu.p [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Paduszynski, Kamil; Zolek-Tryznowska, Zuzanna [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

    2011-02-15

    (Liquid + liquid) phase equilibria (LLE) of binary mixtures containing hyperbranched polymer Boltorn (registered) H2004 and n-alkanes (n-hexane, n-heptane, n-octane, and n-decane) were studied over the temperature range from about (260 up to 360) K. The polymer is partially miscible with n-alkanes and the solubility decreases with an increase of the chain length of the solvent. Corresponding LLE phase diagrams including spinodal and binodal (liquid + liquid) coexistence curves were calculated in terms of the statistical mechanics - based on the lattice-cluster theory, based only on the upper critical solution temperature, and the polymer chain architecture. The results show semi-qualitative agreement of predicted and experimental equilibrium compositions and temperatures. Boltorn (registered) H2004 reveals complete miscibility in the liquid phase with alcohols (C{sub 1}-C{sub 8}), aromatic hydrocarbons (benzene, toluene, and thiophene), and ethers (methyl tetra-butyl ether, ethyl tetra-butyl ether, and tetrahydrofurane).

  10. Pressure-sensitive adhesion system using acrylate block copolymers in response to photoirradiation and postbaking as the dual external stimuli for on-demand dismantling.

    Science.gov (United States)

    Inui, Tadashi; Sato, Eriko; Matsumoto, Akikazu

    2012-04-01

    We have demonstrated the validity of a new type of pressure-sensitive adhesion system using block copolymers containing a poly(2-ethylhexyl acrylate) (P2EHA) segment as the low glass transition temperature polymer and a poly(tert-butyl acrylate) (PtBA) or poly(isobornyl acrylate) (PIBoA) segment as the reacting polymer in the presence of a photoacid generator (PAG). This adhesion system can be easily debonded because of a change in the polymer properties of the adhesives by acid-catalyzed deprotection uniquely occurring during the photoirradiation followed by postbaking. We investigated the transformation of PtBA and PIBoA into poly(acrylic acid) using IR spectroscopy and a thermogravimetric analysis in the presence of p-toluenesulfonic acid and the PAGs. The block copolymers with a well-defined molecular structure were then synthesized by atom transfer radical polymerization, and their adhesive properties were evaluated using the 180° peel test. The block copolymers showed superior adhesion property than a random copolymer and polymer blends, due to the microphase separation of the block copolymers. A drastic change in the adhesive strength of the block copolymers was observed in response to the dual external stimuli consisting of UV irradiation and the subsequent heating.

  11. The use of dielectric spectroscopy for the characterisation of the precipitation of hydrophobically modified poly(acrylic-acid) with divalent barium ions

    DEFF Research Database (Denmark)

    Christensen, Peter Vittrup; Keiding, Kristian

    2009-01-01

    The use of dielectric spectroscopy as a monitor for coagulation processes was investigated. Hydrophobically modified poly(acrylic-acid) polymers were used as model macromolecules and coagulated with barium ions. The coagulation process was quantified using a photometric dispersion analyser, thereby...

  12. Dataset for acrylate/silica nanoparticles formulations and photocured composites: Viscosity, filler dispersion and bulk Poisson׳s ratio

    Directory of Open Access Journals (Sweden)

    Hubert Gojzewski

    2017-06-01

    Full Text Available UV-curable polymer composites are of importance in industry, biomedical applications, scientific fields, and daily life. Outstanding physical properties of polymer composites were achieved with nanoparticles as filler, primarily in enhancing mechanical strength or barrier properties. Structure-property relationships of the resulting nanocomposites are dictated by the polymer-filler molecular architecture, i.e. interactions between polymer matrix and filler, and high surface area to volume ratio of the filler particles. Among monomers, acrylates and methacrylates attracted wide attention due to their ease of polymerization and excellent physicochemical and mechanical properties of the derived polymers. We prepared and photopolymerized two series of formulations containing hydrophobized silica nanofiller (Aerosil R7200 dispersed in 2-hydroxyethyl acrylate (HEA or polyethylene glycol diacrylate (PEGDA monomers. We compared selected physical properties of the formulations, both before and after photocuring; specifically the viscosity of formulations and dispersion of the filler in the polymer matrices. Additionally, we estimated the bulk Poisson׳s ratio of the investigated nanocomposites. This article contains data related to the research article entitled “Nanoscale Young׳s modulus and surface morphology in photocurable polyacrylate/nanosilica composites” (Gojzewski et al., 2017 [1].

  13. Sodium Carboxymethyl Cellulose Using Acrylamide and Acrylic Acid and Investigation of Drug Delivery Properties

    Directory of Open Access Journals (Sweden)

    Mahdi Geramipour

    2016-07-01

    Full Text Available Hydrogels are three-dimensional polymer networks that can absorb and retain a huge amount of aqueous fluids even under certain pressure, but do not dissolve in water. They are responsive to environmental stimulants such as pH and ionic strength of the solution. In this study, a series of novel sodium carboxymethyl cellulose-based hydrogel nanocomposites were synthesized using acrylamide comonomer in the presence of iron magnetic as crosslinker and acrylic acid ammonium persulfate (APS comonomer as initiator. All reaction variables affecting the water absorbency of the hydrogel nanocomposite including the concentration of crosslinking agent and initiator, and comonomers ratio were optimized in order to achieve the maximum absorption capacity. The experimental data showed that the hydrogel nanocomposite exhibited improved swelling capacity compared to the nanoparticel-free hydrogel. In addition, optimized hydrogel nanocomposite showed a good water uptake ability and the equilibrium swelling capacity was achieved within the initial 10 min. In examining the quality of the synthesized hydrogel nanocomposite, the amount of absorption in saline solutions of different concentrations was measured. Furthermore, the swelling behavior of hydrogel nanocomposite in solutions with different pH values was evaluated. The chemical structure of the hydrogel nanocomposites was characterized by means of transmission electron microscopy (TEM, scanning electron microscopy (SEM, vibrating sample magnetometry (VSM, thermogravimetry analysis (TGA, derivative thermogravimetry (DTG and Fourier transform infrared spectroscopy (FTIR. In order to study the drug delivery and drug release behavior, the release of sodium diclofenac as a model drug from synthesized hydrogel nanocomposite was examined in two acidic and basic buffer environments. The results indicated that this hydrogel nanocomposite may be an appropriate alternative for drug release processes in human body.

  14. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement.

  15. Histological analysis of cobalt-chromium stents with and without Camouflage® polymer coating: experimental porcine carotid artery model.

    Science.gov (United States)

    Grudtner, Marco Aurélio; de Lara Elesbão, Joao Luiz; Gutierrez, Paulo Sérgio; Meyer, Fabíola Schons; Pereira, Adamastor Humberto

    2011-04-01

    This study evaluated the arterial response to cobalt-chromium stents with and without polymer coating (Camouflage®, Hemoteq AG, Wuerselen, Germany) implanted in pigs. Cobalt-chromium balloon-expandable stents (4 × 16 mm) were implanted in the common carotid arteries of nine pigs. Histological analysis of endothelialization, inflammation and injury was performed one month later. All stents were successfully deployed, and all but one animal survived the 30 study days. All arteries were patent. Endothelialization was nearly complete in most sections of all carotid stents in both groups. There were mild inflammatory infiltrate and mild-to-moderate injury, which were associated with the stent shafts and not significantly different between groups. Our findings suggest that, in porcine carotid arteries, the histological response to balloon-expandable cobalt-chromium stents coated with polymer (Camouflage®, Hemoteq AG) is similar to the response to non-coated cobalt-chromium stents.

  16. Photocatalytic oxygen evolution from low-bandgap conjugated microporous polymer nanosheets: a combined first-principles calculation and experimental study.

    Science.gov (United States)

    Wang, Lei; Wan, Yangyang; Ding, Yanjun; Niu, Yuchen; Xiong, Yujie; Wu, Xiaojun; Xu, Hangxun

    2017-03-23

    Nanostructured semiconducting polymers have emerged as a very promising class of metal-free photocatalytic materials for solar water splitting. However, they generally exhibit low efficiency and lack the ability to utilize long-wavelength photons in a photocatalytic oxygen evolution reaction (OER). Here, based on first-principles calculations, we reveal that the two-dimensional (2D) aza-fused conjugated microporous polymer (aza-CMP) with a honeycomb network is a semiconductor with novel layer-dependent electronic properties. The bandgap of the as-synthesized aza-CMP nanosheets is measured to be 1.22 eV, suggesting that they can effectively boost light absorption in the visible and near infrared (NIR) region. More importantly, aza-CMP also possesses a valence band margin suitable for a photocatalytic OER. Taking advantage of the 2D layered nanostructure, we further show that the exfoliated ultrathin aza-CMP nanosheets can exhibit a three-fold enhancement in the photocatalytic OER. After deposition of a Co(OH) 2 cocatalyst, the hybrid Co(OH) 2 /aza-CMP photocatalyst exhibits a markedly improved performance for photocatalytic O 2 evolution. Furthermore, first-principles calculations reveal that the photocatalytic O 2 evolution reaction is energetically feasible for aza-CMP nanosheets under visible light irradiation. Our findings reveal that nanostructured polymers hold great potential for photocatalytic applications with efficient solar energy utilization.

  17. METHACRYLATE AND ACRYLATE ALLERGY IN DENTAL STUDENTS.

    Directory of Open Access Journals (Sweden)

    Maya Lyapina

    2013-09-01

    Full Text Available A multitude of acrylic monomers is used in dentistry, and when dental personnel, patients or students of dental medicine become sensitized, it is of great importance to identify the dental ;acrylic preparations to which the sensitized individual can be exposed. Numerous studies confirm high incidence of sensitization to (meth acrylates in dentatal professionals, as well as in patients undergoing dental treatment and exposed to resin-based materials. Quite a few studies are available aiming to evaluate the incidence of sensitization in students of dental medicineThe purpose of the study is to evaluate the incidence of contact sensitization to some (meth acrylates in students of dental medicine at the time of their education, in dental professionals (dentists, nurses and attendants and in patients, the manifestation of co-reactivity.A total of 139 participants were included in the study, divided into four groups: occupationally exposed to (methacrylates and acrylic monomers dental professionals, 3-4 year-of-education students of dental medicine, 6th year–of-education students of dental medicine and patients with suspected or established sensitization to acrylates, without occupational exposure. All of them were patch-tested with methyl methacrylate (MMA, triethyleneglycol dimethacrylate (TREGDMA, ethyleneglycol dimethacrylate (EGDMA, 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy phenyl]propane (bis-GMA, 2-hydroxyethyl methacrylate (2-HEMA, and tetrahidrofurfuril metacrylate. The overall sensitization rates to methacrylates in the studied population are comparative high – from 25.9% for MMA to 31.7% for TREGDMA. Significantly higher incidence of sensitization in the group of 3-4 course students compared to the one in the group of dental professionals for MMA and TREGDMA was observed. Highest was the incidence of sensitization to ethyleneglycol dimethacrylate, BIS-GMA, 2-HEMA and tetrahydrofurfuryl methacrylate in the group of patients, with

  18. COLLAPSE KINETIC OF COMPOSITES BASED ON COPOLYMERS OF ACRYLIC ACID AND ACRYLAMIDE FILLED WITH BENTONITE IN AQUEOUS SOLUTIONS OF POLYVALENT METALS

    Directory of Open Access Journals (Sweden)

    V. E. Sitnikova

    2017-01-01

    Full Text Available Polymer polyelectrolyte hydrogel composites of acrylic acid and acrylamide copolymer filled with different amounts of bentonite (from 1 to 5 wt.% were synthesized. Collapse kinetics of hydrogel composites was studied in solutions of different concentrations of polyvalent metal salts at a constant temperature of 25 °C. The mass of water given away from hydrogels into the solution was determined by gravimetric method. It has been found that the presence of bentonite in the polyelectrolyte hydrogel composites prevents to some extent collapse in electrolyte solutions, due to steric and electrostatic interactions between the filler particles. These interactions preclude further collapse of hydrogels. The Peleg's kinetic model, most precisely describing experimental data, was applied to calculation of kinetic constants of polymer hydrogels collapse. It is shown that the initial collapse rate and the kinetic constant of collapse and swelling depend non-monotonically on the concentration (ionic strength in the electrolyte solution. At the identical concentration of salts in the solution the kinetic constant of hydrogel collapse is independent of the radius of ions of metals of the studied salts.

  19. Preparation of nanogels by radiation-induced cross-linking of interpolymer complexes of poly (acrylic acid) with poly (vinyl pyrrolidone) in aqueous medium

    Science.gov (United States)

    Ghaffarlou, Mohammadreza; Sütekin, S. Duygu; Güven, Olgun

    2018-01-01

    Functional nanogels were prepared from interpolymer complexes (IPC) of poly (vinyl pyrrolidone) and poly (acrylic acid) by gamma irradiation of their aqueous solutions. The coil size of IPCs prepared under different experimental conditions (polymer molecular weight, concentration, mixing ratios, pH and temperature) were measured by Dynamic Light Scattering (DLS) technique prior to irradiation. At relatively low absorbed doses of 5 and 10 kGy, IPC nanogels with a range of 30-250 nm diameters, -12 to -28 mV zeta potentials and polydispersities lower than 0.17 were obtained. The sizes of the nanogels were found to be smaller than the size of the precursor IPC coil sizes (40-300 nm) due to the formation of intra-chain crosslinks. Thus a recipe of preparing multifunctional nanogels with double amphiphilic properties carrying polyacidic and nonionic polymer structures with the range of above listed properties has been developed. These nanogels show narrow size distribution and high colloidal stability increasing their potential to be used as biocompatible drug carriers with controlled-release properties. PVP-PAA IPC nanogels were characterized by dynamic light scattering (DLS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques.

  20. Photo-induced copper-mediated polymerization of methyl acrylate in continuous flow reactors

    OpenAIRE

    Wenn, Benjamin; CONRADI, Matthias; Carreiras, Andre Demetrio; Haddleton, David M.; Junkers, Thomas

    2014-01-01

    Photo-induced copper-mediated radical polymerization of methyl acrylate (MA) is carried out in DMSO at 15 °C in a tubular photo-flow reactor as well as in a glass-chip based microreactor. Polymerization reactions proceed rapidly to approximately 90% monomer conversion within 20 minutes of reactor residence time. Control of reactions is high as evidenced by ideal polymerization kinetics, low dispersities of the obtained polymers (in the range of 1.1) and linear evolution of number average mole...

  1. The Thickness And Stretch Dependence Of The Electrical Breakdown Strength Of An Acrylic Dielectric Elastomer

    Science.gov (United States)

    Huang, Jiangshui; Suo, Zhigang; Clarke, David

    2013-03-01

    The performance of dielectric elastomer actuators is limited by electrical breakdown. Attempts to measure this are confounded by the voltage-induced thinning of the elastomer. A test configuration is introduced that avoids this problem: A thin sheet of elastomer is stretched, crossed-wire electrodes attached, and then embedded in a stiff polymer. The applied electric field at breakdown EB is found to depend on both the deformed thickness, h, and the stretch applied, λ. For the acrylic elastomer investigated, the breakdown field scales as EB = 51h - 0 . 25λ 0 . 63 . The test configuration allows multiple individual tests to be made on the same sheet of elastomer.

  2. High Solid Contents Copoly (Styrene/Butyl Acrylate-Cloisite 30B Nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Mirzataheri

    2013-03-01

    Full Text Available Higher solid contents (20 % and 40 % nanocomposites of poly (styrene-co-butyl acrylate including higher content of Cloisite 30B (7 wt% and 10 wt % were prepared via miniemulsion polymerization. Stability of the final latexes proved outstanding combination of polymerization procedure and surfactants. Morphological studies revealed by TEM, SAX and XRD showed three structures of core-shell, armored and individual dispersion of clay layers within the polymer particles. The effect of Cloisite 30B content on the barrier properties presents excellent and wide use of these films for packaging and nanocoatings industries.

  3. Structure and properties of poly(benzyl acrylate) synthesized under microwave energy

    Energy Technology Data Exchange (ETDEWEB)

    Oberti, Tamara G. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET Casilla de Correo 16, Sucursal 4, 1900 La Plata (Argentina); Laboratorio de Estudio de Compuestos Organicos (LADECOR), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Schiavoni, M. Mercedes [Laboratorio de Estudio de Compuestos Organicos (LADECOR), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Cortizo, M. Susana [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET Casilla de Correo 16, Sucursal 4, 1900 La Plata (Argentina)], E-mail: gcortizo@inifta.unlp.edu.ar

    2008-05-15

    Benzyl acrylate was polymerized under microwave irradiation using radical initiation (benzoyl peroxide, BP). The effect of the concentration of BP and power irradiation on the conversion, average molecular weights and the polydispersity index (M{sub w}/M{sub n}) were investigated. The {sup 1}H NMR and {sup 13}C NMR spectra analysis showed tendency to syndiotacticity and branched polymers were obtained at high conversion of reactions. A significant enhancement of the rates of polymerization and similar thermodynamic behavior, as compared with those obtained under thermal conditions was found.

  4. Thiolated polymers: evaluation of their potential as dermoadhesive excipients.

    Science.gov (United States)

    Grießinger, Julia Anita; Bonengel, Sonja; Partenhauser, Alexandra; Ijaz, Muhammad; Bernkop-Schnürch, Andreas

    2017-02-01

    The objective of this study was to evaluate and compare four different thiolated polymers regarding their dermoadhesive potential. Therefore, three hydrophilic polymers (poly(acrylic acid), Carbopol 971 and carboxymethylcellulose) and a lipophilic polymer (silicone oil) were chosen to generate thiolated polymers followed by characterization. The total work of adhesion (TWA) and the maximum detachment force (MDF) of formulations containing modified and unmodified polymers were investigated on skin obtained from pig ears using a tensile sandwich technique. The synthesis of thiolated polymers provided 564 µmol, 1079 µmol, 482 µmol and 217 µmol thiol groups per gram poly(acrylic acid), Carbopol 971, carboxymethylcellulose and silicone oil, respectively. Hydrogels containing poly(acrylic acid)-cysteine, Carbopol 971-cysteine, and carboxymethylcellulose-cysteamine exhibited a 6-fold, 25-fold and 9-fold prolonged adhesion on porcine skin than the hydrogel formulations prepared from the corresponding unmodified polymers, respectively. Furthermore, thiolation of silicone oil with thioglycolic acid led to a 5-fold improvement in adhesion compared to the unmodified silicone oil. A comparison between the four thiolated polymer formulations showed a clear correlation between the amount of coupled thiol groups and the TWA. According to these results thiomers might also be useful excipients to provide a prolonged dermal resistance time of various formulations.

  5. Shear bond strength of acrylic teeth to acrylic denture base after different surface conditioning methods.

    Science.gov (United States)

    Madhav, Gajula Venu; Raj, Soundar; Yadav, Naveen; Mudgal, Ishitha; Mehta, Nidhi; Tatwadiya, Riddhi

    2013-09-01

    Acrylic resin ruled the dental profession for 60 years, and this success is attributed to its aesthetics, handling properties, physical and biological compatibility, its stability in oral environment and its cost effectiveness. The objective of this study is to evaluate and compare the bond strength of acrylic resin teeth treated with various conditioning materials like monomer and silane coupling agent. METHDOLOGY: A study was carried out in which 96 samples were grouped into 3 groups with a sample size of 32 each (16 premolars, 16 molars). They were conditioned with different conditioning materials i,e monomer and silane coupling agent. Monomer, Silane coupling agent are coated on the ridge lap area before thermocycling and cured according to the manufacturer recommendations. The samples are retained from the fask; trimmed and polished. The samples are then subjected to shear bond strength using the Insteron Universal Testing Machine. In the present study it was found that application of monomer increased the bond strength between acrylic teeth and denture base, when compared to the conventionally processed samples. However it was found that application of silane coupling agent further increased the shear bond strength between acrylic teeth and denture base. Interprations and Within the confnes of this study it is found that there was a signifcant improvement in the bond strength between the acrylic teeth and denture base when silane coupling agent and monomer were used as surface conditioning material. The order of shear strength of samples is control > monomer > silane coupling agent.

  6. Allergic contact dermatitis from dental composite resins due to aromatic epoxy acrylates and aliphatic acrylates.

    Science.gov (United States)

    Kanerva, L; Estlander, T; Jolanki, R

    1989-03-01

    7 patients were occupationally sensitized to dental composite resin products (DCR): 6 dental nurses and 1 dentist. All had a positive patch test to their DCR. 2 independent types of allergy were seen; (a) aromatic epoxy acrylate, and/or (b) aliphatic acrylates. 4 out of 5 patients reacted to BIS-GMA, the most widely used aromatic epoxy acrylate in DCR, but not the dentist. She and 2 dental nurses were allergic to aliphatic acrylates, including triethylene glycol dimethacrylate (TREGDMA) and triethylene diglycol diacrylate (TREGDA). 4 patients were allergic to epoxy resin (ER) (containing mainly MW 340), possibly an impurity in some DCR. 2 patients were also allergic to methyl methacrylate (MMA): the dentist, had been exposed to MMA, but the nurse's exposure was uncertain. 1 patient was also allergic to rubber gloves, 2 to rubber chemicals but not their gloves, and 5 to disinfectants used. diagnosis was delayed as long as 13 years in spite of previous patch testing. Dermatologists need to use the patients' own DCR and the (meth)acrylate series for patch testing. No dental nurses could continue their occupation, but the dentist could occasionally handle DCR if wearing PVC gloves. Dental personnel need to know about the risks of DCR, and use no-touch techniques and protective gloves.

  7. Temperature dependence of the dielectric constant of acrylic dielectric elastomer

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Junjie; Chen, Hualing; Li, Bo; Chang, Longfei [Xi' an Jiaotong University, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an (China); Xi' an Jiaotong University, School of Mechanical Engineering, Xi' an (China)

    2013-02-15

    The dielectric constant is an essential electrical parameter to the achievable voltage-induced deformation of the dielectric elastomer. This paper primarily focuses on the temperature dependence of the dielectric constant (within the range of 173 K to 373 K) for the most widely used acrylic dielectric elastomer (VHB 4910). First the dielectric constant was investigated experimentally with the broadband dielectric spectrometer (BDS). Results showed that the dielectric constant first increased with temperature up to a peak value and then dropped to a relative small value. Then by analyzing the fitted curves, the Cole-Cole dispersion equation was found better to characterize the rising process before the peak values than the Debye dispersion equation, while the decrease process afterward can be well described by the simple Debye model. Finally, a mathematical model of dielectric constant of VHB 4910 was obtained from the fitted results which can be used to further probe the electromechanical stability of the dielectric elastomers. (orig.)

  8. Temperature dependence of the dielectric constant of acrylic dielectric elastomer

    Science.gov (United States)

    Sheng, Junjie; Chen, Hualing; Li, Bo; Chang, Longfei

    2013-02-01

    The dielectric constant is an essential electrical parameter to the achievable voltage-induced deformation of the dielectric elastomer. This paper primarily focuses on the temperature dependence of the dielectric constant (within the range of 173 K to 373 K) for the most widely used acrylic dielectric elastomer (VHB 4910). First the dielectric constant was investigated experimentally with the broadband dielectric spectrometer (BDS). Results showed that the dielectric constant first increased with temperature up to a peak value and then dropped to a relative small value. Then by analyzing the fitted curves, the Cole-Cole dispersion equation was found better to characterize the rising process before the peak values than the Debye dispersion equation, while the decrease process afterward can be well described by the simple Debye model. Finally, a mathematical model of dielectric constant of VHB 4910 was obtained from the fitted results which can be used to further probe the electromechanical stability of the dielectric elastomers.

  9. Optimal Design for Reactivity Ratio Estimation: A Comparison of Techniques for AMPS/Acrylamide and AMPS/Acrylic Acid Copolymerizations

    OpenAIRE

    Scott, Alison J.; Marzieh Riahinezhad; Alexander Penlidis

    2015-01-01

    Water-soluble polymers of acrylamide (AAm) and acrylic acid (AAc) have significant potential in enhanced oil recovery, as well as in other specialty applications. To improve the shear strength of the polymer, a third comonomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), can be added to the pre-polymerization mixture. Copolymerization kinetics of AAm/AAc are well studied, but little is known about the other comonomer pairs (AMPS/AAm and AMPS/AAc). Hence, reactivity ratios for AMPS/AAm ...

  10. Propagation of ultrasonic guided waves in an acrylic plate as a cortical-bone-mimicking phantom

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Il [Kangwon National University, Chuncheon (Korea, Republic of); Choi, Bok Kyoung [Maritime Security Research Center, KIOST, Ansan (Korea, Republic of)

    2014-12-15

    The present study aims to investigate the propagation of ultrasonic guided waves in an acrylic plate as a cortical-bone-mimicking phantom. The velocities of the guided waves in a 5-mm-thick acrylic plate were measured by using the axial transmission technique. A pure A0 Lamb mode could be successfully launched in the 5-mm-thick acrylic plate through a time reversal process of Lamb waves, consistent with the fact that the time reversal process can automatically compensate for the dispersive nature of Lamb waves. The experimental velocities of the slow guided wave (SGW) and the time-reversed Lamb wave were found to be in reasonable agreement with the theoretical group velocity of the A0 Lamb mode, suggesting that both the SGW and the time-reversed Lamb wave excited in the 5-mm-thick acrylic plate correspond to the A0 Lamb mode. These results suggest that the time reversal process of Lamb waves can be usefully applied to noninvasive characterization of long cortical bones.

  11. Computational study of the self-initiation mechanism in thermal polymerization of methyl acrylate.

    Science.gov (United States)

    Srinivasan, Sriraj; Lee, Myung Won; Grady, Michael C; Soroush, Masoud; Rappe, Andrew M

    2009-10-08

    This computational study deals with the mechanism of spontaneous initiation in thermal polymerization of alkyl acrylates (e.g., methyl, ethyl, and n-butyl acrylate). The mechanism is presently still unknown. Density-functional theory (DFT) and Møller-Plesset (MP2) calculations are used to explore the Flory and Mayo mechanisms of self-initiation in methyl acrylate. On the singlet surface, a low-barrier, concerted [4 + 2] Diels-Alder mechanism for the formation of a dihydropyran adduct (DA) and a high-barrier nonconcerted [2 + 2] diradical ((*)M(2s)(*)) mechanism for the formation of dimethyl cyclobutane-1,2-dicarboxylate (DCD) were found using B3LYP/6-31G*. Several levels of theory were used to validate the transition states, and the pathways for the DA and DCD formations on the singlet surface were determined using intrinsic reaction coordinate (IRC) calculations. On the triplet surface, a triplet diradical intermediate ((*)M(2t)(*)) was identified that is structurally similar to (*)M(2s)(*) but lower in energy. The spin-orbit coupling constant for crossover of the diradical from singlet to triplet surface was calculated. Monoradical generation from the two intermediates, DA and (*)M(2t)(*) via hydrogen transfer to or from a third methyl acrylate was studied. It was found that generation of two monoradical species was possible from (*)M(2t)(*) and is proposed as a likely explanation for experimentally observed spontaneous-initiation.

  12. An effective method and pathways of acrylonitrile degradation to acrylic acid through an alkaline hydrothermal system.

    Science.gov (United States)

    Dong, Wenjie; Peng, Boyu; Wang, Ke; Miao, Jia; Zhang, Wei; Zhang, Yalei; Shen, Zheng

    2017-07-01

    Degradation of pollution for specific chemicals represents an optimal approach to high-strength wastewater treatment. One-pot selective conversion of acrylonitrile to acrylic acid in a hydrothermal system with NaOH as a catalyst was carried out. The influence factors were evaluated, including initial acrylonitrile concentration, reaction temperature, reaction time and amount of alkali. Experimental results showed that the highest yield of acrylic acid (55%) was obtained at the initial acrylonitrile concentration of 3 × 10(3) mg/L, 300°C for 90 s with 1.0 M NaOH. To determine the reaction path, intermediates analysis and calculation of carbon and nitrogen balance were carried out by means of HPLC, GC and TOC/TN methods. Two probable reaction pathways were proposed as follows: (1) Acrylonitrile was hydrolyzed into acrylamide, and acrylic acid was obtained via further hydrolysis. (2) Acrylonitrile was converted into 3-hydroxy-propionitrile via additive reaction, and this product was readily converted to 3-hydroxy-propionic acid through two steps of hydrolysis, followed by dehydration reaction to produce acrylic acid. This study offered not only an efficient method to transfer highly toxic pollutants into valuable chemical, but also a better understanding of hydrothermal alkali catalytic reaction.

  13. Experimental approach for mixed-mode fatigue delamination crack growth with large-scale bridging in polymer composites

    DEFF Research Database (Denmark)

    Holmes, John W.; Liu, Liu; Sørensen, Bent F.

    2014-01-01

    of delaminations in a typical fibre-reinforced polymer composite was investigated under a constant cyclic loading amplitude. Pure mode I, mode II and mixed-mode crack growth conditions were examined. The results, analysed using a J-integral approach, show that the double cantilever beam loaded with uneven bending...... crack growth rate observed. In addition to details concerning the equipment, a general discussion of the development of cyclic bridging laws for delamination growth in the presence of large-scale bridging is provided....

  14. Control and experimental characterization of a methanol reformer for a 350W high temperature polymer electrolyte membrane fuel cell system

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen; Jensen, Hans-Christian Becker

    suited for reformer systems, where high CO tolerance is required. This enables the use fuels based on e.g. liquid alcohols. This work presents the control strategies of a methanol refoermer for a 350W HTPEM FC system. The system examined is the Serenergy H3-350 Mobile Battery Charger, an integrated......High temperature polymer electrolyte membrane(HTPEM) fuel cells offer many advantages due to their increased operating tempera-tures compared to similar Nafion-based membrane tech-nologies, that rely on the conductive abilities of liquid water. The polybenzimidazole (PBI) membranes are especially...

  15. Waterborne polyurethane-acrylic hybrid nanoparticles by miniemulsion polymerization: applications in pressure-sensitive adhesives.

    Science.gov (United States)

    Lopez, Aitziber; Degrandi-Contraires, Elise; Canetta, Elisabetta; Creton, Costantino; Keddie, Joseph L; Asua, José M

    2011-04-05

    Waterborne polyurethane-acrylic hybrid nanoparticles for application as pressure-sensitive adhesives (PSAs) were prepared by one-step miniemulsion polymerization. The addition of polyurethane to a standard waterborne acrylic formulation results in a large increase in the cohesive strength and hence a much higher shear holding time (greater than seven weeks at room temperature), which is a very desirable characteristic for PSAs. However, with the increase in cohesion, there is a decrease in the relative viscous component, and hence there is a decrease in the tack energy. The presence of a small concentration of methyl methacrylate (MMA) in the acrylic copolymer led to phase separation within the particles and created a hemispherical morphology. The tack energy was particularly low in the hybrid containing MMA because of the effects of lower energy dissipation and greater cross-linking. These results highlight the great sensitivity of the viscoelastic and adhesive properties to the details of the polymer network architecture and hence to the precise composition and synthesis conditions.

  16. New blends of ethylene-butyl acrylate copolymers with thermoplastic starch. Characterization and bacterial biodegradation.

    Science.gov (United States)

    Morro, A; Catalina, F; Corrales, T; Pablos, J L; Marin, I; Abrusci, C

    2016-09-20

    Ethylene-butyl acrylate copolymer (EBA) with 13% of butyl acrylate content was used to produce blends with 10, 30 and 60% of thermoplastic starch (TPS) plasticized with glycerol. Ethylene-acrylic acid copolymer (EAA) was used as compatibilizer at 20% content with respect to EBA. The blends were characterized by X-ray diffraction, ATR-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), water-Contact Angle measurements (CA), Differential Scanning Calorimetry (DSC) and Stress-strain mechanical tests. Initiated autoxidation of the polymer blends was studied by chemiluminescence (CL) confirming that the presence of the polyolefin-TPS interphase did not substantially affect the oxidative thermostability of the materials. Three bacterial species have been isolated from the blend films buried in soil and identified as Bacillus subtilis, Bacillus borstelensis and Bacillus licheniformis. Biodegradation of the blends (28days at 45°C) was evaluated by carbon dioxide measurement using the indirect impedance technique. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Characterizing acrylic pressure-sensitive adhesive tapes favoring diverse biomedical applications

    Science.gov (United States)

    Alhijji, Saleh Mohammed S.

    Strong, self-adhesive acrylic polymer-based tapes have been identified as FDA-approved medical device construction components that might also serve in diverse biological locations as artificial muscles, ligaments, or compressive support discs. After assuring that the tapes themselves were not cytotoxic, they were evaluated as possible low-tension muscle substitutes for eyelids, jaws, and other modest body re-closing needs, and well as for higher-tension applications as artificial ligaments. Self-adhesion of the tapes to representative biomaterials, before and after radio-frequency glow discharge treatment for surface energy modification, illustrated the conditions for maximum attachment strength to nonphysiologic substances. Attachment to bony host parts was challenging but apparently met by the application of acrylic-composite-to-dentin bonding systems that has shown good long-term experience in the mouth. Above all, the compression-relaxation properties of the tape materials were superior and their uses in potential Nucleus Pulposus applications for spinal disc repair were most completely explored. Tests included tape-disc performance longevity, both dry and wet, for over 5000 load-relaxation cycles, with no apparent changes in results for the most dense of the tapes evaluated. Direct abrasion was avoided by insertion of rigid polymeric layers. It is recommended that the compressive loading properties of acrylic tapes be further evaluated for spine repair applications.

  18. Quantum chemistry investigation of secondary reaction kinetics in acrylate-based copolymers.

    Science.gov (United States)

    Cuccato, Danilo; Mavroudakis, Evangelos; Moscatelli, Davide

    2013-05-30

    Recently, a growing amount of attention has been focused on the influence of secondary reactions on the free radical polymerization features and the properties and microstructure of the final polymer, particularly in the context of acrylate copolymers. One of the most challenging aspects of this research is the accurate determination of the corresponding reaction kinetics. In this paper, this problem is addressed using quantum chemistry. The reaction rate coefficients of various backbiting, propagation, and β-scission steps are estimated considering different chain configurations of a terpolymer system composed of methyl acrylate, styrene, and methyl methacrylate. The replacement of methyl acrylate radical units with styrene and methyl methacrylate globally decreases the backbiting probability and shifts the equilibrium toward the reactants, while the effect of replacing adjacent units is weaker and more dependent upon the specific substituting monomer. Propagation kinetics is affected primarily by the replacement of the radical units, while this effect appears to be particularly effective on midchain radical reactivity. The overall results clarify the different physicochemical behavior of chain-end, midchain, and short-branch radicals as a function of copolymer composition, providing new insights into free radical polymerization kinetics.

  19. Isobornyl acrylate: an impurity in alkyl glucosides.

    Science.gov (United States)

    Foti, Caterina; Romita, Paolo; Rigano, Luigi; Zimerson, Erik; Sicilia, Mattia; Ballini, Andrea; Ghizzoni, Oscar; Antelmi, Annarita; Angelini, Gianni; Bonamonte, Domenico; Bruze, Magnus

    2016-01-01

    Alkyl glucosides and alkyl poly-glucosides are widely used as wetting agents, surfactants and emulsifiers in several industrial and cosmetic products. They are known as well-tolerated and are usually added to the primary surfactants in order to reduce the irritating potential of the main foaming agents. Recently, some authors suggested that allergic contact dermatitis to alkyl glucosides might be more frequent than suspected. On the other hand, the chemical structures of glucosides do not show potentially allergenic chemical groups or strongly polarized structures. The aim of our study is to investigate alkyl glucosides carrying out a detailed chemical analysis on samples of raw materials to identify potentially allergenic impurities or by-products contained in commercial samples of alkyl glucosides. We chemically analyzed samples of cocoyl glucoside, decyl glucoside and lauryl glucoside by three different analytical methods, in order to identify any undesired or polluting substances. In each of the three samples, we detected the presence of isobornyl acrylate. Its approximate content in the tested samples is 500 ng/g of the product. Isobornyl acrylate is not used in the synthesis of alkyl glucosides, but as a plasticizer in many plastic materials. It can be easily released to materials flowing over these surfaces when they have high extraction power, as glucosides. Isobornyl acrylate may play a role as hidden allergen, in the form of an impurity collected during the industrial process, explaining some cases of allergic reaction to alkyl glucosides.

  20. Acrylated Chitosan Nanoparticles with Enhanced Mucoadhesion

    Directory of Open Access Journals (Sweden)

    Shaked Eliyahu

    2018-01-01

    Full Text Available The aim of this study was to investigate the effect of acrylate modification on the mucoadhesion of chitosan at the nanoscale. Nanoparticles were fabricated from acrylated chitosan (ACS via ionic gelation with tripolyphosphate and were characterized in terms of size, zeta potential, stability, and nanoparticle yield. Chitosan (CS nanoparticles, serving as a control, were fabricated using the same procedure. The mucoadhesion of the nanoparticles was evaluated using the flow-through method after different incubation periods. The retention percentages of ACS nanoparticles were found to be significantly higher than those of CS nanoparticles, for all studied time intervals. An additional indication for the increased mucoadhesion of ACS nanoparticles was the increase in particle size obtained from the mucin particle method, in which mucin and nanoparticles are mixed at different ratios. NMR data verified the presence of free acrylate groups on the ACS nanoparticles. Thus, the improved mucoadhesion could be due to a Michael-type addition reaction between the nanoparticles and thiol groups present in mucin glycoprotein, in addition to entanglements and hydrogen bonding. Overall, ACS nanoparticles exhibit enhanced mucoadhesion properties as compared to CS nanoparticles and could be used as vehicles for drug delivery systems.

  1. Contact allergy to acrylates/methacrylates in the acrylate and nail acrylics series in southern Sweden: simultaneous positive patch test reaction patterns and possible screening allergens.

    Science.gov (United States)

    Teik-Jin Goon, Anthony; Bruze, Magnus; Zimerson, Erik; Goh, Chee-Leok; Isaksson, Marléne

    2007-07-01

    In a recent study we showed that all our dental personnel/patients were detected with 2-hydroxyethyl methacrylate (2-HEMA) and 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA). We studied 90 patients tested to the acrylate and nail acrylics series at our department over a 10 year period to see whether screening allergens could be found. Patch testing with an acrylate and nail acrylics series was performed. Among the 10 acrylate/methacrylate-allergic occupational dermatitis patients tested to the acrylate series, the most common allergens were triethyleneglycol diacrylate (TREGDA, 8), diethyleneglycol diacrylate (5), and 1,4-butanediol diacrylate (BUDA, 5). All 10 of these patients would have been picked up by a short screening series combining TREGDA, 2-hydroxypropyl methacrylate (2-HPMA), and BUDA or 1,6-hexanediol diacrylate (HDDA). Among the 14 acrylate/methacrylate-allergic nail patients, the most common allergens were ethylene glycol dimethacrylate (EGDMA, 11), 2-HEMA, (9), and triethyleneglycol dimethacrylate (9). Screening for 3 allergens i.e. 2-HEMA plus EGDMA plus TREGDA, would have detected all 14 nail patients. A short screening series combining 2-HEMA, EGDMA, TREGDA, 2-HPMA, bis-GMA, and BUDA or HDDA would have picked up all our past study patients (dental, industrial, and nail) with suspected allergy to acrylate/methacrylate allergens.

  2. Removal of acrylic coatings from works of art by means of nanofluids: understanding the mechanism at the nanoscale.

    Science.gov (United States)

    Baglioni, Michele; Rengstl, Doris; Berti, Debora; Bonini, Massimo; Giorgi, Rodorico; Baglioni, Piero

    2010-09-01

    Conservation of works of art often involves the inappropriate application of synthetic polymers. We have proposed the use of alternative methodologies for conservation and formulated innovative cleaning nanostructured systems to remove previously applied polymer films and grime from painted surfaces. In particular, a novel "micellar system" composed of water, SDS, 1-pentanol, ethyl acetate and propylene carbonate was recently formulated and successfully used to remove acrylic and vinyl/acrylic copolymers from Mesoamerican wall paintings in the archeological site of Cholula, Mexico. This contribution reports on the mechanism of the interaction process that takes place between the nanostructured fluid and the polymer coating at the nanoscale. The structural properties of the "micellar solution" and of the polymer film are investigated before, during and after the interaction process using several surface and solution techniques. Rather than a classical detergency mechanism, we demonstrate that micelles act as solvent containers and interact with the polymer film leading to its swelling and detachment from the surface and to its segregation in a liquid droplet, which phase-separates from the aqueous bulk. After the removal process the micelles become smaller in size and undergo a structural re-arrangement due to the depletion of the organic solvents. These findings can be framed in an interaction mechanism which describes the removal process, opening up new perspectives in the design and formulation of new cleaning systems specifically tailored for intervention on particular conservation issues.

  3. Removal of acrylic coatings from works of art by means of nanofluids: understanding the mechanism at the nanoscale

    Science.gov (United States)

    Baglioni, Michele; Rengstl, Doris; Berti, Debora; Bonini, Massimo; Giorgi, Rodorico; Baglioni, Piero

    2010-09-01

    Conservation of works of art often involves the inappropriate application of synthetic polymers. We have proposed the use of alternative methodologies for conservation and formulated innovative cleaning nanostructured systems to remove previously applied polymer films and grime from painted surfaces. In particular, a novel ``micellar system'' composed of water, SDS, 1-pentanol, ethyl acetate and propylene carbonate was recently formulated and successfully used to remove acrylic and vinyl/acrylic copolymers from Mesoamerican wall paintings in the archeological site of Cholula, Mexico. This contribution reports on the mechanism of the interaction process that takes place between the nanostructured fluid and the polymer coating at the nanoscale. The structural properties of the ``micellar solution'' and of the polymer film are investigated before, during and after the interaction process using several surface and solution techniques. Rather than a classical detergency mechanism, we demonstrate that micelles act as solvent containers and interact with the polymer film leading to its swelling and detachment from the surface and to its segregation in a liquid droplet, which phase-separates from the aqueous bulk. After the removal process the micelles become smaller in size and undergo a structural re-arrangement due to the depletion of the organic solvents. These findings can be framed in an interaction mechanism which describes the removal process, opening up new perspectives in the design and formulation of new cleaning systems specifically tailored for intervention on particular conservation issues.

  4. Experimental Study on Rise Husk Ash & Fly Ash Based Geo-Polymer Concrete Using M-Sand

    Science.gov (United States)

    Nanda Kishore, G.; Gayathri, B.

    2017-08-01

    Serious environmental problems by means of increasing the production of Ordinary Portland cement (OPC), which is conventionally used as the primary binder to produce cement concrete. An attempt has been made to reduce the use of ordinary Portland cement in cement concrete. There is no standard mix design of geo-polymer concrete, an effort has been made to know the physical, chemical properties and optimum mix of geo-polymer concrete mix design. Concrete cubes of 100 x 100 x 100 mm were prepared and cured under steam curing for about 24 hours at temperature range of 40°C to 60°C. Fly ash is replaced partially with rice husk ash at percentage of 10%, 15% and 25%. Sodium hydroxide and sodium silicate are of used as alkaline activators with 5 Molar and 10 Molar NaOH solutions. Natural sand is replaced with manufacture sand. Test results were compared with controlled concrete mix of grade M30. The results shows that as the percentage of rice husk ash and water content increases, compressive strength will be decreases and as molarity of the alkaline solution increases, strength will be increases.

  5. Experimental verification of displacement control on integrated ionic polymer-metal composite actuators with stochastic on/off controller

    Science.gov (United States)

    Kimura, Keishiro; Kamamichi, Norihiro

    2017-04-01

    An ionic polymer-metal composite (IPMC) actuator is one of polymer-based soft actuators. It is produced by chemically plating gold or platinum on both surface of a perfluorosulfonic acid membrane which is known as an ion-exchange membrane. It is able to be activated by a simple driving circuit and generate a large deformation under a low applied voltage (0.5-3 V). However, individual difference and characteristics changes from environmental conditions should be considered for realizing a stable or precise control. To solve these problems, we applied a stochastic ON/OFF controller to an integrated IPMC actuator with parallel connections. The controller consists of a central controller and distributed controllers. The central controller broadcasts a control signal such as an error signal to distributed controllers uniformly. The distributed controllers switch the ON/OFF states based on the broadcasted signal stochastically. The central controller dose not measure the states of each IPMC actuator, and the control signals is calculated by using the output signal of the integrated actuator and reference signal. The validity of the applied method was investigated through numerical simulations and experiments.

  6. [Sensitization to acrylates caused by artificial acrylic nails: review of 15 cases].

    Science.gov (United States)

    Roche, E; de la Cuadra, J; Alegre, V

    2008-12-01

    Allergic contact dermatitis due to acrylates present in the workplace is a disease frequently reported among dentists, printers, and fiberglass workers. Recently, the number of cases of contact allergic dermatitis among beauticians specialized in sculpting artificial nails has increased. Our objective was to study the clinical characteristics and allergens implicated in allergic contact dermatitis due to acrylates in beauticians and users of sculpted nails. This was an observational, retrospective study of patients diagnosed with allergic contact dermatitis due to acrylates used in sculpting artificial nails over the last 26 years in the Hospital General Universitario, Valencia, Spain. In total, 15 patients were diagnosed: 14 beauticians and 1 client. Most cases were diagnosed in the past 2 years. All were women, their mean age was 32.2 years, and 26.7 % had a personal or family history of atopy. The sensitization time varied between 1 month and 15 years. The most frequently affected areas were the fleshy parts of the fingers and hands. Three patients - 2 beauticians and 1 client - presented allergic asthma due to acrylates. All patients underwent patch testing with a standard battery of allergens and a battery of acrylates. The most frequent allergens were ethylene glycol dimethacrylate (13/15, 86.7 %), hydroxyethyl methacrylate (13/15, 86.7 %), triethylene glycol dimethacrylate (7/15, 46.7 %), 2-hydroxypropyl methacrylate (5/15, 33.3 %), and methyl methacrylate (5/15, 33.3 %). Acrylate monomers used for sculpting artificial nails are important sensitizers for contact and occupational dermatitis. The most important consideration is primary and secondary prevention.

  7. Synthesis, characterization and antimicrobial activity of important heterocyclic acrylic copolymers

    Directory of Open Access Journals (Sweden)

    2008-10-01

    Full Text Available The acrylate monomer, 7-acryloyloxy-4-methyl coumarin (AMC has been synthesized by reacting 7-hydroxy-4-methyl coumarin, with acryloyl chloride in the presence of NaOH at 0–5°C. Copolymers of 7-acryloyloxy-4-methyl coumarin (AMC with vinyl acetate (VAc were synthesized in DMF (dimethyl formamide solution at 70±1°C using 2,2′-azobisisobutyronitrile (AIBN as an initiator with different monomer-to-monomer ratios in the feed. The copolymers were characterized by Fourier transform infra red (FTIR spectroscopy. The copolymer composition was evaluated by 1H-NMR (proton nuclear magnetic resonance and was further used to determine reactivity ratios. The monomer reactivity ratios for AMC (M1-VAc (M2 pair were determined by the application of conventional linearization methods such as Fineman-Ross (r1 = 0.6924; r2 = 0.6431, Kelen-Tüdõs (r1 = 0.6776; r2 = 0.6374 and extended Kelen-Tüdõs (r1 = 0.6657; r2 = 0.6256. Thermo gravimetric analysis showed that thermal decomposition of the copolymers occurred in single stage in the temperature range of 263–458°C. The molecular weights of the polymers were determined using gel permeation chromatography. The homo and copolymers were tested for their antimicrobial properties against selected microorganisms.

  8. Poly(acrylic acid)-directed synthesis of colloidally stable single domain magnetite nanoparticles via partial oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Altan, Cem L. [Department of Chemical Engineering, Yeditepe University, Istanbul 34755 (Turkey); Laboratory of Materials and Interface Chemistry & Soft Matter cryoTEM Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Gurten, Berna [Department of Chemical Engineering, Yeditepe University, Istanbul 34755 (Turkey); Sadza, Roel [Laboratory of Materials and Interface Chemistry & Soft Matter cryoTEM Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Yenigul, Elcin [Department of Chemical Engineering, Yeditepe University, Istanbul 34755 (Turkey); Sommerdijk, Nico A.J.M., E-mail: n.sommerdijk@tue.nl [Laboratory of Materials and Interface Chemistry & Soft Matter cryoTEM Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Bucak, Seyda, E-mail: seyda@yeditepe.edu.tr [Department of Chemical Engineering, Yeditepe University, Istanbul 34755 (Turkey)

    2016-10-15

    Octahedral, single domain magnetite nanoparticles with average size of ~55 nm were synthesized through oxidative aging of a ferrous hydroxide (Fe(OH){sub 2}) precursor at high pH in water. The synthesis was also carried out in the presence of the hydrophilic polymer poly(acrylic acid). Presence of the polymer changed the particle morphology from octahedral to spherical while average size decreased to 40–50 nm. Although these particles have a tendency to precipitate due to their high magnetic moment, dispersions of these particles were obtained in the presence of this particular polymer which made the particles stable in water for several days making them suitable for various biotechnological applications such as cell separation owing to their low toxicity. - Highlights: • Stable, single domain magnetite nanoparticles are synthesized via partial oxidation. • Particles are readily stabilized in water by a biocompatible polymer. • Steric barrier is essential for the stabilization of large magnetite nanoparticles.

  9. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  10. In Vitro Antifungal Evaluation of Seven Different Disinfectants on Acrylic Resins

    OpenAIRE

    Yildirim-Bicer, A. Z.; Peker, I.; Akca, G.; Celik, I.

    2014-01-01

    Objective. The aim of this study was to evaluate alternative methods for the disinfection of denture-based materials. Material and Methods. Two different denture-based materials were included in the study. Before microbial test, the surface roughness of the acrylic resins was evaluated. Then, the specimens were divided into 8 experimental groups (n = 10), according to microorganism considered and disinfection methods used. The specimens were contaminated in vitro by standardized suspensions o...

  11. Acrylate contact allergy: patient characteristics and evaluation of screening allergens.

    Science.gov (United States)

    Drucker, Aaron Mark; Pratt, Melanie Dawn

    2011-01-01

    Acrylates are present in a wide variety of products and cause occupational and non-occupational allergic contact dermatitis. There is no clear guidance from the literature as to which allergens should be used for patch-test screening for acrylates. To characterize patients with contact allergy to acrylates and to evaluate the allergens used to screen for acrylate allergy. Charts of patients visiting an outpatient contact dermatitis clinic from January 1998 to February 2008 were reviewed retrospectively. Forty-four patients were found to have contact allergy to acrylates. The most commonly positive allergens were hydroxyethyl methacrylate (HEMA), ethyl acrylate (EA), and methyl methacrylate (MMA). Thirty-two of the 44 positive patch-test results (73%) would have been discovered with the use of the two compounds (MMA, EA) in the North American Standard Series (Chemotechnique screening series), a commercially available screening series, while 12 were found through expanded patch testing. Artificial nails, dental materials, and adhesives were the most common exposures. Occupational relevance was found in 18 cases, including those of dental workers, assemblers, and aestheticians. Acrylates are an important cause of contact allergy. Screening series identify most cases of acrylate allergy but miss a substantial number. Clinicians should remain vigilant for acrylate allergy even if initial screening is negative.

  12. Severe Onychodystrophy due to Allergic Contact Dermatitis from Acrylic Nails.

    Science.gov (United States)

    Mattos Simoes Mendonca, Marcela; LaSenna, Charlotte; Tosti, Antonella

    2015-09-01

    Acrylic nails, including sculptured nails and the new ultraviolet-curable gel polish lacquers, have been associated with allergic contact dermatitis (ACD). We report 2 cases of ACD to acrylic nails with severe onychodystrophy and psoriasiform changes including onycholysis and subungual hyperkeratosis. In both cases, the patients did not realize the association between the use of acrylate-based manicures and nail changes. One patient had been previously misdiagnosed and treated unsuccessfully for nail psoriasis. The informed clinician should elicit a history of acrylic manicure in patients with these nail changes, especially in cases of suspected nail psoriasis refractory to treatment. Patch testing is a useful tool in confirming diagnosis.

  13. Occupational allergic contact dermatitis due to acrylates in Lodz.

    Science.gov (United States)

    Kiec-Swierczynska, M K

    1996-06-01

    Among 1619 patients suspected of occupational contact dermatitis examined during the years 1990-1994, sensitivity to acrylates was diagnosed in 9 persons (4 dental technicians, 4 dentists, 1 textile printer). Ethyleneglycol dimethacrylate (5 positive patch tests), methyl methacrylate (4), 2-hydroxyethyl methacrylate (4) and triethyleneglycol dimethacrylate (4) were the most common sensitizers. Comparison of patch test results in dental technicians and dentists indicated that dentists were sensitive to a greater number of (meth)acrylate (acrylate and methacrylate) allergens and also to certain other allergens (metals and rubber additives). Dental technicians were sensitive almost exclusively to methacrylates, while the textile printer only to acrylates.

  14. Fibronectin fixation on poly(ethyl acrylate)-based copolymers.

    Science.gov (United States)

    Briz, N; Antolinos-Turpin, C M; Alió, J; Garagorri, N; Ribelles, J L Gómez; Gómez-Tejedor, J A

    2013-08-01

    The aim of this paper is to quantify the adhered fibronectin (FN; by adsorption and/or grafting) and the exposure of its cell adhesive motifs (RGD and FNIII7-10) on poly(ethyl acrylate) (PEA) copolymers whose chemical composition has been designed to increase wettability and to introduce acid functional groups. FN was adsorbed to PEA, poly(ethyl acrylate-co-hydroxyethyl acrylate), poly(ethyl acrylate-co-acrylic acid), and poly(ethyl acrylate-co-methacrylic acid) copolymers, and covalently cross-linked to poly(ethyl acrylate-co-acrylic acid) and poly(ethyl acrylate-co-methacrylic acid) copolymers. Amount of adhered FN and exhibition of RGD and FNIII7- 10 fragments involved in cell adhesion were quantified with enzyme-linked immunosorbent assay tests. Even copolymers with a lower content of the hydrophilic component showed a decrease in water contact angle. In addition, FN was successfully fixed on all surfaces, especially on the hydrophobic surfaces. However, it was demonstrated that exposure of its cell adhesion sequences, which is the key factor in cell adhesion and proliferation, was higher for hydrophilic surfaces. Copyright © 2013 Wiley Periodicals, Inc.

  15. In-situ experimental characterization of the clamping pressure effects on low temperature polymer electrolyte membrane electrolysis

    DEFF Research Database (Denmark)

    Al Shakhshir, Saher; Cui, Xiaoti; Frensch, Steffen Henrik

    2017-01-01

    The recent acceleration in hydrogen production’s R&D will lead the energy transition. Low temperature polymer electrolyte membrane electrolysis (LT-PEME) is one of the most promising candidate technologies to produce hydrogen from renewable energy sources, and for synthetic fuel production. LT......-PEME splits water into hydrogen and oxygen when the voltage is applied between anode and cathode. Electrical current forces the positively charged ions to migrate to negatively charged cathode through PEM, where hydrogen is produced. Meanwhile, oxygen is produced at the anode side electrode and escapes...... as a gas with the circulating water. The effects of clamping pressure (Pc) on the LT-PEME cell performance, polarization resistances, and hydrogen and water crossover through the membrane, and hydrogen and oxygen production rate are studied. A 50 cm2 active area LT-PEME cell designed and manufactured...

  16. Synthesis of Poly(styrene-acrylates-acrylic acid Microspheres and Their Chemical Composition towards Colloidal Crystal Films

    Directory of Open Access Journals (Sweden)

    Luis A. Ríos-Osuna

    2016-01-01

    Full Text Available In this paper, polystyrene colloidal microspheres have been prepared using hexyl acrylate (HA, ethylhexyl acrylate (EHA, isooctyl acrylate (IOA, butyl acrylate (BA, or isobutyl acrylate (IBA as comonomers. Microspheres with diameters from 212 to 332 nm and with a polystyrene content of 65–78% were prepared. The particles prepared in this work do not present the typical core-shell structure; as a consequence, DSC analysis showed that the microspheres exhibited only one Tg. TEM images show that the particles with comonomer content below ~30% were spherical and regular. Microspheres containing comonomer between 21 to 25% produced the less brittle films showing very iridescent colors. The films prepared from microspheres containing hexyl, ethylhexyl, and isooctyl acrylate as comonomers are firmly attached to the substrate due to their adhesive properties. The large decrease of the fragility observed in these films makes them much more attractive materials in sensing applications.

  17. Kinetics and products of gas-phase reactions of ozone with methyl methacrylate, methyl acrylate, and ethyl acrylate.

    Science.gov (United States)

    Bernard, F; Eyglunent, G; Daële, V; Mellouki, A

    2010-08-19

    The kinetics and products of the gas-phase reactions of ozone with methyl methacrylate, methyl acrylate, and ethyl acrylate have been investigated at 760 Torr total pressure of air and 294 +/- 2 K. The rate coefficients obtained (in cm(3) molecule(-1) s(-1) units) were as follows: k(methyl methacrylate) = (6.7 +/- 0.9) x 10(-18), k(methyl acrylate) = (0.95 +/- 0.07) x 10(-18), and k(ethyl acrylate) = (1.3 +/- 0.1) x 10(-18). In addition to formaldehyde being observed as a product of the three reactions, the other major reaction products were methyl pyruvate from reaction of ozone with methyl methacrylate, methyl glyoxylate from reaction of ozone with methyl acrylate, and ethyl glyoxylate from reaction of ozone with ethyl acrylate. Possible reaction mechanisms leading to the observed products are presented and discussed.

  18. Effect of black tea on the transverse strength of heat-polymerized acrylic resin

    Directory of Open Access Journals (Sweden)

    Eni Rahmi

    2017-11-01

    Full Text Available Introduction: Heat-polymerized acrylic resin is the most basic denture material used. One of the mechanical properties of an acrylic resin is its transverse strength. The transverse strength test provides an overview of the material's durability in accepting the load at mastication. Consumption of tea, especially black tea in the world placed the second most consumed. The purpose of this study was to determine the effect of black tea on the transverse strength of heat-polymerized acrylic resin. Methods: This research was an experimental laboratory with 24 samples of heat-polymerized acrylic resin plate with the size of 65 x 10 x 2.5 mm. The sample was divided into 6 groups, each consisted of 4 samples. The first, second, and the third groups were immersed in aquadest for consecutively 1, 4, and 20 days. The fourth, fifth, and sixth groups were immersed in the black tea for consecutively 1, 4, and 20 days. The transverse strength was tested using the three-point bending method with the Universal Testing Machine. The results of the transverse strength measurement were then analyzed statistically by the One-way ANOVA test and Holm's sequential Bonferroni posthoc test as an advanced test. Results: The results of the statistical test showed that p < 0,05 (p = 0,000 which means that the six groups have a significant difference in the average value of the transverse strength. Conclusion: The conclusion of this research was the black tea immersion duration was affecting the transverse strength difference of the heat-polymerized acrylic resin.

  19. Latex imaging by environmental STEM: application to the study of the surfactant outcome in hybrid alkyd/acrylate systems.

    Science.gov (United States)

    Faucheu, Jenny; Chazeau, Laurent; Gauthier, Catherine; Cavaillé, Jean-Yves; Goikoetxea, Monika; Minari, Roque; Asua, José M

    2009-09-01

    Among other uses, latexes are a successful alternative to solvent-borne binders for coatings. Efforts are made to produce hybrid nanostructured latexes containing an acrylic phase and an alkyd phase. However, after the film-forming process, the surfactant used to stabilize these latexes remains in the film, and its location can have a drastic effect on the application properties. Among the processing parameters, the alkyd hydrophobicity can strongly influence this location. This article aims at the imaging of these surfactant molecules in two hybrid latexes with different hydrophobicity level of the alkyd resin. A first part of this paper is dedicated to the understanding of the contrast provided by the surfactant in environmental STEM imaging of latexes. Then, the influence of surfactant-polymer affinity on the surfactant location after film-forming of those hybrid alkyd/acrylate latexes is studied by this technique. It is shown that in the hybrid latex with an alkyd shell (obtained with the most hydrophilic resin), the surfactant molecules tend to remain buried in the alkyd phase. Conversely, in the hybrid latex with an acrylate shell (in the case of the most hydrophobic resin), the surfactant molecules tend to gather into islands like in pure acrylate latex films.

  20. Comparison between an Acrylic Splint Herbst and an Acrylic Splint Miniscrew-Herbst for Mandibular Incisors Proclination Control

    OpenAIRE

    Manni, Antonio; Pasini, Marco; Mazzotta, Laura; Mutinelli, Sabrina; Nuzzo, Claudio; Grassi, Felice Roberto; Cozzani, Mauro

    2014-01-01

    Aim. The aim of this study is to compare dental and skeletal effects produced by an acrylic splint Herbst with and without skeletal anchorage for correction of dental class II malocclusion. Methods. The test group was formed by 14 patients that were treated with an acrylic splint miniscrew-Herbst; miniscrews were placed between mandibular second premolars and first molars; controls also consisted of 14 subjects that were treated with an acrylic splint Herbst and no miniscrews. Cephalometric m...

  1. Monomers, polymers and articles containing the same from sugar derived compounds

    Science.gov (United States)

    Gallagher, James; Reineke, Theresa; Hillmyer, Marc A.

    2016-11-29

    Disclosed herein are monomers formed by reacting a sugar derived compound(s) comprising a lactone and two hydroxyls with a compound(s) comprising an isocyanate and an acrylate or methacrylate. Polymers formed from such monomers, and articles formed from the polymers are also disclosed.

  2. An experimental and simulation study of novel channel designs for open-cathode high-temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Thomas, Sobi; Bates, Alex; Park, Sam

    2016-01-01

    A minimum balance of plant (BOP) is desired for an open-cathode high temperature polymer electrolyte membrane (HTPEM) fuel cell to ensure low parasitic losses and a compact design. The advantage of an open-cathode system is the elimination of the coolant plate and incorporation of a blower...... for oxidant and coolant supply, which reduces the overall size of the stack, power losses, and results in a lower system volume. In the present study, we present unique designs for an open-cathode system which offers uniform temperature distribution with a minimum temperature gradient and a uniform flow...... distribution through each cell. Design studies were carried out to increase power density. An experimental and simulation approach was carried out to design the novel open-cathode system. Two unique parallel serpentine flow designs were developed to yield a low pressure drop and uniform flow distribution, one...

  3. Fast and Simple Preparation of Patterned Surfaces with Hydrophilic Polymer Brushes by Micromolding in Capillaries.

    Science.gov (United States)

    Vonhören, Benjamin; Langer, Marcel; Abt, Doris; Barner-Kowollik, Christopher; Ravoo, Bart Jan

    2015-12-22

    Micropatterns of hydrophilic polymer brushes were prepared by micromolding in capillaries (MIMIC). The polymers are covalently bound to the surfaces by a rapid hetero Diels-Alder reaction, constituting the first example of polymers grafted to surfaces in a defined pattern by MIMIC. The polymers [poly(acrylic acid), poly(hydroxyethyl acrylate), and poly(tetraethylene glycol acrylate) ranging in molecular weight from 1500 to 6000 g mol(-1)] were prepared with narrow dispersities via the reversible addition-fragmentation chain transfer (RAFT) process using a highly electron deficient RAFT agent that can react with surface-anchored dienes such as cyclopentadiene. We demonstrate that the anchoring method is facile to perform and highly suitable for preparing patterned surfaces that are passivated against biological impact in well-defined areas.

  4. Acrylic-acid-functionalized PolyHIPE scaffolds for use in 3D cell culture.

    Science.gov (United States)

    Hayward, Adam S; Sano, Naoko; Przyborski, Stefan A; Cameron, Neil R

    2013-12-01

    This study describes the development of a functional porous polymer for use as a scaffold to support 3D hepatocyte culture. A high internal phase emulsion (HIPE) is prepared containing the monomers styrene (STY), divinylbenzene (DVB), and 2-ethylhexyl acrylate (EHA) in the external oil phase and the monomer acrylic acid (Aa) in the internal aqueous phase. Upon thermal polymerization with azobisisobutyronitrile (AIBN), the resulting porous polymer (polyHIPE) is found to have an open-cell morphology and a porosity of 89%, both suitable characteristics for 3D cell scaffold applications. X-ray photo-electron spectroscopy reveals that the polyHIPE surface contained 7.5% carboxylic acid functionality, providing a useful substrate for subsequent surface modifications and bio-conjugations. Initial bio-compatibility assessments with human hepatocytes show that the acid functionality does not have any detrimental effect on cell adhesion. It is therefore believed that this material can be a useful precursor scaffold towards 3D substrates that offer tailored surface functionality for enhanced cell adhesion. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Preparation of Photoresponsive Functionalized Acrylic Nanoparticles Cantaining Carbazole Groups for Smart Cellulosic Papers

    Directory of Open Access Journals (Sweden)

    Jaber Keyvan Rad

    2017-11-01

    Full Text Available Photoresponsive functionalized polymer nanoparticles were prepared as useful materials for preparation of smart papers. Such polymer nanoparticles have wide applications in several fields including papers, sensors, bioimaging and biomedicine. First, carbazole as a photosensitive compound was modified with 2-bromoethanol through substitution nucleation reaction to its hydroxyl derivative (N-(2-hydroxyethyl carbazole, CzEtOH. The synthesis of 2-N-carbazolylethyl acrylate (CzEtA monomer was carried out by modification reaction of CzEtOH with acryloyl chloride and the chemical structures of the products were characterized. Next, CzEtA, methyl methacrylate (MMA and butyl acrylate were copolymerized to prepare photoresponsive functionalized polymer nanoparticles through mini-emulsion polymerization in order to form a hydrophobic core. This was followed by copolymerization of MMA and glycidyl methacrylate by seeded emulsion polymerization to give a functionalized outer layer on the latex particles. Absorption characteristics, size, size distribution (narrow size distribution and morphology of the nanoparticles were studied by ultraviolet-visible (UV-Vis spectroscopy, dynamic laser light scattering (DLS analysis and scanning electron microscopy (SEM micrographs, respectively. Finally, due to the importance of photoresponsive smart papers and their wide applications, cellulosic fibers were reacted with the prepared functionalized latex particles for preparation of smart papers. Morphology of the fibers was investigated with respect to the surface-immobilized polymers on the cellulosic paper and their smart behavior was evaluated by UV irradiation at 254 nm. The results revealed fast color changes and the obtained cellulosic papers became violet upon irradiation. This work shows some promising feature of these materials for preparation of anti-counterfeiting papers, where the safety becomes a major concern.

  6. Preparation, Characterization and Permeation Behavior of Poly(methyl acrylate-Poly(dimethyl siloxane-Poly(methyl acrylate Block Copolymer/Poly(vinyl acetate Blend Membranes

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Semsarzadeh

    2015-03-01

    Full Text Available Structure of polymeric materials is of the most important factors in determination of the characteristics and properties of the membranes. Various research and developments on polymeric membranes confirm the direct correlation between structure-properties of polymeric membranes. In this research, the structural outcome of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate/poly(vinyl acetate blend membranes and its relationship with gas permeation behavior of the blends were investigated. The flexible block copolymer of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate (PMA-PDMS-PMA was synthesized via atom transfer radical polymerization. Morphology and chemical structure of the synthesized block copolymer was investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, X-ray diffraction analysis, differential scanning calorimetry and scanning electron microscopy. Blend membranes of PMA-PDMS-PMA and poly(vinyl acetate (PVAc were prepared by solution casting method in different compositions. By adding poly(vinyl acetate to PMA-PDMS-PMA block copolymer, the selectivity of the membranes for carbon dioxide/methane pair gases were increased by 55%. Fractional free volume (an indication of chain packing efficiency in blend membranes and dielectric constant (an indication of the molar volume and molar polarization of the blend membranes were obtained as the factors reflected the microstructural effect of PMA-PDMS-PMA and PVAc blend membranes. The efforts were directed toward expressing more precise structure-properties relationship of PMA-PDMS-PMA/PVAc blend membranes. The experimental permeability values of the blend membranes reported in this research were compared with the modified logarithmic model. The modified logarithmic model was evaluated for other blend membranes.

  7. [Synthesis and characterization of dihydroeugenol acrylate].

    Science.gov (United States)

    Liu, Xiao-Huan; Wang, Chun-Peng; Wang, Ji-Fu; Xu, Yu-Zhi; Chu, Fu-Xiang

    2014-04-01

    Dihydroeugenol acrylate was synthesized by the reaction of acryloyl chloride (AC) with lignin mode compound dihydroeugenol (DH) in the presence of TEA and characterized by using FTIR, GC/MS, 1H-NMR and GPC. FTIR spectra showed that, after the esterification with acryloyl chloride, the intensity of stretching vibration peak of O-H (centered at 3 495 cm(-1)) of DH was disappeared. At the same time, a new peak appeared at 1 762 cm(-1) which was assigned to ester group. Additionally, the appearance of 1 631 and 981 cm(-1) were attributed to the carbon - carbon double bond confirmed the success in the synthesis of DH-AC. 1H-NMR spectra showed that, after the esterification with acryloyl chloride, the proton signal of O-H at 5.5 ppm was disappeared. Meanwhile, the appearance of three new proton signals at 6.0 ppm, 6.4 and 6.7 ppm, attributed to the vinylic protons, indicated that acryloyl chloride was successfully grafted onto DH. The results further confirmed the structures of the DH-AC. GC-MS results showed the DH-AC had a high purity of 98.63%. GPC results showed that dihydroeugenol acrylate could polymerize in the 1,4-dioxane using a thermal initiator of AIBN (2.0 Wt% of total monomers). The weight average molecular mass (Mw) of the homopolymer is 37 400 g x mol(-1), and the number average molecular mass is 23 400 g x mol(-1)' with a polydispersity index Mw/Mn of 1.60, indicating that the dihydroeugenol acrylate has high polymerization activity. This strategy provides a novel approach for extending the comprehensive utilization of lignin.

  8. Occupational dermatitis due to an epoxy acrylate.

    Science.gov (United States)

    Kanerva, L; Jolanki, R; Estlander, T

    1986-02-01

    A dental assistant developed sensitivity to dental restorative materials within 3 months of starting to use them. They contained the epoxy acrylate BIS-GMA, which is the most commonly used dimethacrylate monomer in dental composite restorations. She was positive to a patch test with BIS-GMA, which was the probable allergen, and epoxy resin, but this substance was not present in the materials used, as shown by high performance liquid chromatography. The patient was also allergic to the disinfectant Desimex i containing dodecyl diaminoethyl glycine.

  9. [Reticulate polymers used in obtaining new dental materials].

    Science.gov (United States)

    Budală, Dana Gabriela; Vlad, Cristina Doina; Forna, Norina Consuela

    2010-01-01

    This paper seeks the characterization of new polymers acrylic cross-linked structure, prepared in the presence of a template that creates the polymer synthesized the property of saving template form. For carrying out synthesis of polymers reticulate-based on dimethacrylate monomer was left to the mono-, di-and trietilenglicol dimethacrylate. Cross-linked polymerization reaction was initiated with benzoyl peroxide. New structures are obtained witch respond to the need to diversify and improve the biomaterials used in dentistry. The materials are chemically thermally and mechanically inert. Reticulate polymers are non-biodegradable and therefore do not produce intoxication and not degrade biological fluids.

  10. Phenomenology of polymer solution dynamics

    National Research Council Canada - National Science Library

    Phillies, George D. J

    2011-01-01

    ... solutions, not dilute solutions or polymer melts. From centrifugation and solvent dynamics to viscosity and diffusion, experimental measurements and their quantitative representations are the core of the discussion...

  11. Miniemulsion copolymerization of (meth)acrylates in the presence of functionalized multiwalled carbon nanotubes for reinforced coating applications.

    Science.gov (United States)

    Pérez-Martínez, Bertha T; Farías-Cepeda, Lorena; Ovando-Medina, Víctor M; Asua, José M; Rosales-Marines, Lucero; Tomovska, Radmila

    2017-01-01

    Film forming, stable hybrid latexes made of methyl metacrylate (MMA), butyl acrylate (BA) and 2-hydroxyethyl methacrylate (HEMA) copolymer reinforced with modified multiwalled carbon nanotubes (MWCNTs) were synthesized by in situ miniemulsion polymerization. The MWCNTs were pretreated by an air sonication process and stabilized by polyvinylpyrrolidone. The presence of the MWCNTs had no significant effect on the polymerization kinetics, but strongly affected the polymer characteristics (Tg and insoluble polymer fraction). The performance of the in situ composites was compared with that of the neat polymer dispersion as well as with those of the polymer/MWCNT physical blends. The in situ composites showed the presence of an additional phase likely due to the strong interaction between the polymer and MWNCTs (including grafting) that reduced the mobility of the polymer chains. As a result, a substantial increase of both the storage and the loss moduli was achieved. At 60 °C, which is above the main transition region of the polymer, the in situ composites maintained the reinforcement, whereas the blends behaved as a liquid-like material. This suggests the formation of a 3D network, in good agreement with the high content of insoluble polymer in the in situ composites.

  12. Comparison of Candida Albicans Adherence to Conventional Acrylic Denture Base Materials and Injection Molding Acrylic Materials.

    Science.gov (United States)

    Aslanimehr, Masoomeh; Rezvani, Shirin; Mahmoudi, Ali; Moosavi, Najmeh

    2017-03-01

    Candida species are believed to play an important role in initiation and progression of denture stomatitis. The type of the denture material also influences the adhesion of candida and development of stomatitis. The aim of this study was comparing the adherence of candida albicans to the conventional and injection molding acrylic denture base materials. Twenty injection molding and 20 conventional pressure pack acrylic discs (10×10×2 mm) were prepared according to their manufacturer's instructions. Immediately before the study, samples were placed in sterile water for 3 days to remove residual monomers. The samples were then sterilized using an ultraviolet light unit for 10 minutes. 1×10 8 Cfu/ml suspension of candida albicans ATCC-10231 was prepared from 48 h cultured organism on sabouraud dextrose agar plates incubated at 37oC. 100 μL of this suspension was placed on the surface of each disk. After being incubated at 37oC for 1 hour, the samples were washed with normal saline to remove non-adherent cells. Attached cells were counted using the colony count method after shaking at 3000 rmp for 20 seconds. Finally, each group was tested for 108 times and the data were statistically analyzed by t-test. Quantitative analysis revealed that differences in colony count average of candida albicans adherence to conventional acrylic materials (8.3×10 3 ) comparing to injection molding acrylic resins (6×10 3 ) were statistically significant ( p injection acrylic resin materials makes them valuable for patients with high risk of denture stomatitis.

  13. Preliminary Design and Experimental Investigation of a Novel Pneumatic Conveying Method to Disperse Natural Fibers in Thermoset Polymers.

    Science.gov (United States)

    Fahimian, Mahi; Kortschot, Mark; Sain, Mohini

    2016-07-07

    Natural fibers can be attractive reinforcing materials in thermosetting polymers due to their low density and high specific mechanical properties. Although the research effort in this area has grown substantially over the last 20 years, manufacturing technologies to make use of short natural fibers in high volume fraction composites; are still limited. Natural fibers, after retting and preprocessing, are discontinuous and easily form entangled bundles. Dispersion and mixing these short fibers with resin to manufacture high quality, high volume fraction composites presents a significant challenge. In this paper, a novel pneumatic design for dispersion of natural fibers in their original discontinuous form is described. In this design, compressed air is used to create vacuum to feed and convey fibres while breaking down fibre clumps and dispersing them in an aerosolized resin stream. Model composite materials, made using proof-of-concept prototype equipment, were imaged with both optical and X-ray tomography to evaluate fibre and resin dispersion. The images indicated that the system was capable of providing an intimate mixture of resin and detangled fibres for two different resin viscosities. The new pneumatic process could serve as the basis of a system to produce well-dispersed high-volume fraction composites containing discontinuous natural fibres drawn directly from a loosely packed source.

  14. An experimental canine patent ductus arteriosus occlusion device based on shape memory polymer foam in a nitinol cage.

    Science.gov (United States)

    Wierzbicki, Mark A; Raines, Sarah B; Gordon, Sonya G; Criscione, John C; Saunders, Ashley B; Birch, Scott; Due, Bradley; Keller, Brandis; Nash, Landon D; Miller, Matthew W; Maitland, Duncan J

    2017-11-01

    Patent ductus arteriosus (PDA) is a congenital cardiovascular defect in which a fetal connection between the aorta and pulmonary artery does not spontaneously close shortly after birth. If left uncorrected serious complications and even death can occur. Surgical ligation is the traditional treatment method; however, it is an invasive procedure, that motivates development of a minimally invasive option. Shape memory polymer (SMP) foams are unique materials that hold promise in the field of minimally invasive occlusion devices. In this work, a prototype nitinol foam cage (NFC) incorporating SMP foams has been designed and evaluated in multiple mechanical and in vitro verification tests. The NFC demonstrated acceptable fatigue resistance in a preliminary strut integrity test, withstanding one million cycles without complete strut fracture. Radial force analysis of both thick- and thin-walled prototype variations generated less vessel distension and wall tension in a vessel mimic compared to a commercial device. The NFCs exhibited negligible in vitro migration, comparable to that of a commercial device, using simplified, ideal models of PDA. Deployment characteristics of the prototypes were evaluated and compared to that of a commercial device when delivered into physiological models of PDA. During mock deployments, a veterinary cardiologist noted that, while deliverable, the thin-walled NFC prototype exhibited poor deployment characteristics, however the thick-walled NFC had deployment characteristics comparable to that of a commercial device. The promising results of this study warrant further investigation of the NFC device for canine PDA closure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Optimal Topology and Experimental Evaluation of Piezoelectric Materials for Actively Shunted General Electric Polymer Matrix Fiber Composite Blades

    Science.gov (United States)

    Choi, Benjamin B.; Duffy, Kirsten; Kauffman, Jeffrey L.; Kray, Nicholas

    2012-01-01

    NASA Glenn Research Center, in collaboration with GE Aviation, has begun the development of a smart adaptive structure system with piezoelectric (PE) transducers to improve composite fan blade damping at resonances. Traditional resonant damping approaches may not be realistic for rotating frame applications such as engine blades. The limited space in which the blades reside in the engine makes it impossible to accommodate the circuit size required to implement passive resonant damping. Thus, a novel digital shunt scheme has been developed to replace the conventional electric passive shunt circuits. The digital shunt dissipates strain energy through the load resistor on a power amplifier. General Electric (GE) designed and fabricated a variety of polymer matrix fiber composite (PMFC) test specimens. Investigating the optimal topology of PE sensors and actuators for each test specimen has revealed the best PE transducer location for each target mode. Also a variety of flexible patches, which can conform to the blade surface, have been tested to identify the best performing PE patch. The active damping control achieved significant performance at target modes. This work has been highlighted by successful spin testing up to 5000 rpm of subscale GEnx composite blades in Glenn s Dynamic Spin Rig.

  16. Preliminary Design and Experimental Investigation of a Novel Pneumatic Conveying Method to Disperse Natural Fibers in Thermoset Polymers

    Directory of Open Access Journals (Sweden)

    Mahi Fahimian

    2016-07-01

    Full Text Available Natural fibers can be attractive reinforcing materials in thermosetting polymers due to their low density and high specific mechanical properties. Although the research effort in this area has grown substantially over the last 20 years, manufacturing technologies to make use of short natural fibers in high volume fraction composites; are still limited. Natural fibers, after retting and preprocessing, are discontinuous and easily form entangled bundles. Dispersion and mixing these short fibers with resin to manufacture high quality, high volume fraction composites presents a significant challenge. In this paper, a novel pneumatic design for dispersion of natural fibers in their original discontinuous form is described. In this design, compressed air is used to create vacuum to feed and convey fibres while breaking down fibre clumps and dispersing them in an aerosolized resin stream. Model composite materials, made using proof-of-concept prototype equipment, were imaged with both optical and X-ray tomography to evaluate fibre and resin dispersion. The images indicated that the system was capable of providing an intimate mixture of resin and detangled fibres for two different resin viscosities. The new pneumatic process could serve as the basis of a system to produce well-dispersed high-volume fraction composites containing discontinuous natural fibres drawn directly from a loosely packed source.

  17. An experimental study of non-destructive testing on glass fibre reinforced polymer composites after high velocity impact event

    Science.gov (United States)

    Razali, N.; Sultan, M. T. H.; Cardona, F.

    2016-10-01

    A non-destructive testing method on Glass Fibre Reinforced Polymer (GFRP) after high velocity impact event using single stage gas gun (SSGG) is presented. Specimens of C- type and E-type fibreglass reinforcement, which were fabricated with 6mm, 8mm, 10mm and 12mm thicknesses and size 100 mm x 100 mm, were subjected to a high velocity impact with three types of bullets: conical, hemispherical and blunt at various gas gun pressure levels from 6 bar to 60 bar. Visual observation techniques using a lab microscope were used to determine the infringed damage by looking at the crack zone. Dye penetrants were used to inspect the area of damage, and to evaluate internal and external damages on the specimens after impact. The results from visual analysis of the impacted test laminates were discussed and presented. It was found that the impact damage started with induced delamination, fibre cracking and then failure, simultaneously with matrix cracking and breakage, and finally followed by the fibres pulled out. C-type experienced more damaged areas compared to E-type of GFRP.

  18. A novel computational approach for development of highly selective fenitrothion imprinted polymer: theoretical predictions and experimental validations

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Leonardo Augusto de; Pereira, Leandro Alves; Rath, Susanne, E-mail: raths@iqm.unicamp.br [Universidade de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Analitica; Custodio, Rogerio [Universidade de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica

    2014-04-15

    The quality of molecularly imprinted recognition sites depend on the mechanisms and the extent of the functional monomer-template interactions present in the prepolymerization mixture. Thus, an understanding of the physical parameters governing these interactions is key for producing a highly selective molecularly imprinted polymer (MIP). In this paper, novel molecular modeling studies were performed to optimize the conditions for the molecular imprinting of fenitrothion. Four possible functional monomers were evaluated. Five porogenic solvents were investigated employing the polarizable continuum method. The MIP based in methacrylic acid (MAA-MIP) synthesized in the presence of toluene shown to be the most thermodynamically stable complex. Contrarily, MIP based in p-vinylbenzoic acid (PVB-MIP) had the lowest binding energy. According to the adsorption parameters fitted by the Langmuir-Freundlich isotherm, MAA-MIP presented twice the number of binding sites compared to PVB-MIP (103.35 and 53.77 μmol g{sup -1}, respectively) (author)

  19. Optimal topology and experimental evaluation of PE materials for actively shunted GE polymer matrix fiber composite blades

    Science.gov (United States)

    Choi, Benjamin B.; Duffy, Kirsten; Kauffman, Jeffrey L.; Kray, Nicholas

    2012-04-01

    NASA Glenn Research Center (GRC), in collaboration with GE Aviation, has begun the development of a smart adaptive structure system with piezoelectric transducers to improve composite fan blade damping at resonances. Traditional resonant damping approaches may not be realistic for rotating frame applications such as engine blades. The limited space in which the blades reside in the engine makes it impossible to accommodate the circuit size required to implement passive resonant damping. Thus, we have developed a novel digital shunt scheme to replace the conventional electric passive shunt circuits. The digital shunt dissipates strain energy through the load capacitor on a power amplifier. GE designed and fabricated a variety of polymer matrix fiber composite (PMFC) test specimens. We investigated the optimal topology of PE sensors and actuators for each test specimen to discover the best PE transducer location for each target mode. Also a variety of flexible patches, which can conform to the blade surface, have been tested to identify the best performing piezoelectric patch. The active damping control achieved significant performance at target modes. This work has been highlighted by successful spin testing up to 5,000 rpm of subscale GEnx composite blades in GRC's Dynamic Spin Rig.

  20. Determination of gelation doses of gamma-irradiated hydrophilic polymers by different methods

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Fatma; Tekin, Niket; Erkan, Sevin; Gueven, Olgun (Hacettepe Univ., Ankara (Turkey). Dept. of Chemistry)

    1994-04-01

    Poly(acrylic acid) and poly(vinyl pyrrolidone) are hydrophilic polymers. Poly(acrylic acid) is a polyelectrolyte which ionizes in water to produce an electrically conducting medium. In this study, it has been shown that the gelation dose of poly(acrylic acid) can be determined by conductimetric and titrimetric methods with NaOH and measuring pH of aqueous solution of [gamma]-irradiated polymer. In order to develop new, simpler and rapid methods for the determination of gelation dose of PVP, its complexation with gallic acid in dilute aqueous solution has been used. The complex formation between gallic acid and irradiated PVP in aqueous solutions is followed by UV-vis spectroscopy. The reliability of the dose value found, 120 kGy for poly(acrylic acid) and 140 kGy for poly(vinyl pyrrolidone), are also verified by viscometric and solubility measurements. (author).

  1. Synthesis and characterization of metal ion imprinted polymers

    Indian Academy of Sciences (India)

    57

    ABSTRACT. In this study, ion-imprinted polymeric materials to remove metal ions (M2+) like Ni2+, Co2+ etc from an aqueous solution were prepared. To prepare ion-imprinted polymers, acrylic acid derivatives. (XA) like acrylamide (AAm) and methacrylic, itaconic acid were chosen as monomer. Metal ions formed binary ...

  2. Proton microbeam irradiation effects on PtBA polymer

    Indian Academy of Sciences (India)

    Unknown

    irradiation effects on poly-tert-butyl-acrylate (PtBA) polymer using 2⋅0 MeV proton microbeam are reported. Preliminary results on pattern ... sist materials: electromagnetic radiation (e.g. optical, UV or X-ray photons) or charged ... a substrate and depending on the positive or negative type of resist material, the exposed or ...

  3. Blood-compatible poly(2-methoxyethyl acrylate) for the adhesion and proliferation of endothelial and smooth muscle cells.

    Science.gov (United States)

    Sato, Chikako; Aoki, Makiko; Tanaka, Masaru

    2016-09-01

    Thrombus formation presents a serious hindrance in the development of functional artificial blood vessels, especially those with a small diameter. Endothelialization can prevent thrombus formation; however, the adhesion of endothelial cells to existing polymer materials is generally weak. Therefore, polymers that have both anti-thrombotic and endothelialization properties do not currently exist. We previously reported that platelets do not adhere to poly(2-methoxyethyl acrylate) (PMEA) or poly(tetrahydrofurfuryl acrylate)(PTHFA). Here, we investigated whether endothelial cells and smooth muscle cells, both of which are blood vessel components, could adhere to these synthetic polymers. Polyethylene terephthalate films were coated with PMEA and PTHFA using a spin-coater. Human umbilical vein endothelial cells or aorta smooth muscle cells were seeded on the polymer surfaces, after which we analyzed the number of adherent cells, their morphologies and vinculin expression. We found that both endothelial and smooth muscle cells adhered to PMEA and PTHFA, while platelets did not. We propose that, by using PMEA and PTHFA with no modifications, it should be possible to develop artificial blood vessels with both anti-thrombotic and endothelialization properties. In addition, we discuss the mechanism of selective cell adhesion in PMEA and PTHFA. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Acrylate in Phaeocystis colonies does not affect the surrounding bacteria

    NARCIS (Netherlands)

    Noordkamp, DJB; Gieskes, WWC; Gottschal, JC; Forney, LJ; van Rijssel, M

    Acrylate accumulates to concentrations of 1.3-6.5 mM in the mucus of Phaeocystis colonies and may have an effect on the surrounding bacterial community, either as an inhibitor or as a carbon source. Both in the held and in the laboratory, effects of acrylate on bacterial growth and on its

  5. Artificial saliva effect on toxic substances release from acrylic resins.

    Science.gov (United States)

    Kostić, Milena; Krunić, Nebojša; Najman, Stevo; Nikolić, Ljubiša; Nikolić, Vesna; Rajković, Jelena; Petrović, Milica; Igić, Marko; Ignjatović, Aleksandra

    2015-10-01

    Acrylic-based resins are intensively used in dentistry practice as restorative or denture-base materials. The purpose of this study was to analyze the surface structure of denture base resins and the amount of released potentially toxic substances (PTS) immediately upon polymerization and incubation in different types of artificial saliva. Storage of acrylic samples in two models of artificial saliva were performed in a water bath at the temperature of 37 +/- 1 degrees C. Analysis of the surface structure of samples was carned out using scanning electronic microscopy analysis immedidtely after polymerization and after the 30-day incubation. The amounts of PTS per day, week and month extracts were measured using high-pressure liquid chromatography. Surface design and amount of PTS in acrylic materials were different and depended on the types and duration of polymerization. The surfaces of tested acrylates became flatter after immersing in solutions of artificial saliva. The degree of acrylic materials release was not dependent on the applied model of artificial saliva. In order to improve biological features of acrylic resin materials, it was recommended that dentures lined with soft or hard cold-polymerized acrylates should be kept at least 1 to 7 days in water before being given to a patient. So, as to reach high degree of biocompatibility preparation of prosthetic restorations from heat-polymerized acrylate was unnecessary.

  6. Artificial saliva effect on toxic substances release from acrylic resins

    Directory of Open Access Journals (Sweden)

    Kostić Milena

    2015-01-01

    Full Text Available Background/Aim. Acrylic-based resins are intensively used in dentistry practice as restorative or denture-base materials. The purpose of this study was to analyze the surface structure of denture base resins and the amount of released potentially toxic substances (PTS immediately upon polymerization and incubation in different types of artificial saliva. Methods. Storage of acrylic samples in two models of artificial saliva were performed in a water bath at the temperature of 37 ± 1°C. Analysis of the surface structure of samples was carried out using scanning electronic microscopy analysis immediately after polymerization and after the 30-day incubation. The amounts of PTS per day, week and month extracts were measured using high-pressure liquid chromatography. Results. Surface design and amount of PTS in acrylic materials were different and depended on the types and duration of polymerization. The surfaces of tested acrylates became flatter after immersing in solutions of artificial saliva. The degree of acrylic materials release was not dependent on the applied model of artificial saliva. Conclusion. In order to improve biological features of acrylic resin materials, it was recommended that dentures lined with soft or hard coldpolymerized acrylates should be kept at least 1 to 7 days in water before being given to a patient. So, as to reach high degree of biocompatibility preparation of prosthetic restorations from heat-polymerized acrylate was unnecessary. [Projekat Ministarstva nauke Republike Srbije, br. 41017

  7. 40 CFR 721.10082 - Amine modified monomer acrylate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amine modified monomer acrylate (generic). 721.10082 Section 721.10082 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.10082 Amine modified monomer acrylate (generic). (a) Chemical substance...

  8. Study of physico-chemical properties of the new film-type material based on ethyl acrylate and 2-hydroxyethyl acrylate

    Directory of Open Access Journals (Sweden)

    Raykhan Rakhmetullaeva

    2015-03-01

    Full Text Available During recent years the complexes based on water swellable hydrophilic polymers with the drugs and preparation of the film materials used in medicine have attracted attention of researchers. Due to the controlled release of drugs and low toxicity, the polymeric film materials are used as drug delivery systems and dressings. Polymeric film materials for drug delivery were obtained first time by grafting 2-hydroxyethyl acrylate (HEA and ethyl acrylate (EA monomers onto polyvinyl alcohol (PVA. In this study, it was found that the films obtained without thermal treatment are soluble in an aqueous medium. Thus, they were heat treated in the range of 1-15 hours at 90-150ºC. Physico-chemical properties of the films have been studied depending on environmental effects as well as methods of obtaining films have been investigated. An increase of the thermal treatment time leads to a decrease in the degree of swelling and reduces the solubility properties of com­posite materials. The surface morphology and thermal properties of films based on HEA-EA were investigated by scanning electron microscopy, thermogravimet­ric analysis and differential scanning calorimetry. It was shown that the surface of obtained films were homogeneous without any bubbles.

  9. Study on the microstructure and water absorption changes of exterior thin-layer polymer renders during natural and artificial ageing

    Directory of Open Access Journals (Sweden)

    Gintare Griciute

    2015-03-01

    Full Text Available This paper presents the experimental investigation results of exterior render of external thermal insulation composite systems (ETICS. The study involved natural (long-term and artificially accelerated (short-term ageing including effect of UV radiation. For research purposes the cycle of accelerated UV radiation ageing test, imitating the impact of one natural year in Lithuanian climate conditions, have been composed and used. In order to determine the visual, microstructure and water absorption changes and find out the correlation between the natural and artificial weathering, the results of tested aged and untreated samples have been compared. The main attention was focused on the changes of structure and physical properties after short-term and long-term ageing tests. The structural changes of render surface of ETICS after UV tests were determined using scanning electron microscope (SEM. The water absorption of ETIC system was determined by partially submerging. Analysis of render surface microstructure showed that UV rays destroy continuous polymer film on the acrylic and silicone render surface, but water absorption of ETICS does not increase in both cases. Water absorption rates of acrylic, silicon and silicate renders after one natural year of exposure become similar. The polymer film formed on exterior acrylic and silicone render surface was destroyed during one year natural and equivalent laboratory ageing. In conjunction, the carbonization process was taking place, the newly formed calcite crystals covering pores and capillaries, consequently the water absorption rate of all ETICS samples decreased.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.4869

  10. Thermo-Oxidative Induced Damage in Polymer Composites: Microstructure Image-Based Multi-Scale Modeling and Experimental Validation

    Science.gov (United States)

    Hussein, Rafid M.; Chandrashekhara, K.

    2017-11-01

    A multi-scale modeling approach is presented to simulate and validate thermo-oxidation shrinkage and cracking damage of a high temperature polymer composite. The multi-scale approach investigates coupled transient diffusion-reaction and static structural at macro- to micro-scale. The micro-scale shrinkage deformation and cracking damage are simulated and validated using 2D and 3D simulations. Localized shrinkage displacement boundary conditions for the micro-scale simulations are determined from the respective meso- and macro-scale simulations, conducted for a cross-ply laminate. The meso-scale geometrical domain and the micro-scale geometry and mesh are developed using the object oriented finite element (OOF). The macro-scale shrinkage and weight loss are measured using unidirectional coupons and used to build the macro-shrinkage model. The cross-ply coupons are used to validate the macro-shrinkage model by the shrinkage profiles acquired using scanning electron images at the cracked surface. The macro-shrinkage model deformation shows a discrepancy when the micro-scale image-based cracking is computed. The local maximum shrinkage strain is assumed to be 13 times the maximum macro-shrinkage strain of 2.5 × 10-5, upon which the discrepancy is minimized. The microcrack damage of the composite is modeled using a static elastic analysis with extended finite element and cohesive surfaces by considering the modulus spatial evolution. The 3D shrinkage displacements are fed to the model using node-wise boundary/domain conditions of the respective oxidized region. Microcrack simulation results: length, meander, and opening are closely matched to the crack in the area of interest for the scanning electron images.

  11. Evaluation of Mixed-mode Integral Invariant for Polymer Material Trough The Couple Experimental-Numerical Process

    Directory of Open Access Journals (Sweden)

    Absi J.

    2010-06-01

    Full Text Available Usually the element of real structures is subject of the mixed mode loadings. This fact can be explained by the elements geometry and the loading orientations. In this case the propagation of the eventual cracks is characterised by the mixed mode kinematics. In order to characterize the fracture process in mixed mode it’s necessary to separate the fracture process in order to evaluate the influence of each mode. Our study is limited to plane configurations. The mixed mode is considered as an association of opening and shear modes. The mixed mode fracture is evaluated trough the experimental tests using the SEN specimen for different mixed mode ratios. The fracture process separation is operated by the invariant integral Mθ. Moreover, our study regroups an experimental and a numerical approaches.

  12. Synthesis of well-defined catechol polymers for surface functionalization of magnetic nanoparticles

    OpenAIRE

    Zhang, Qiang; Nurumbetov, Gabit; Simula, Alexandre; Zhu, Chongyu; Li, Muxiu; Wilson, Paul; Kempe, Kristian; Yang, Bin; tao, lei; Haddleton, David M.

    2016-01-01

    In order to obtain dual-modal fluorescent magnetic nanoparticles, well-defined fluorescent functional polymers with terminal catechol groups were synthesized by single electron transfer living radical polymerization (SET-LRP) under aqueous conditions for “grafting to” modification of iron oxide nanoparticles. Acrylamide, N-isopropylacrylamide, poly(ethylene glycol) methyl ether acrylate, 2-hydroxyethyl acrylate, glycomonomer and rhodamine B piperazine acrylamide were homo-polymerized or block...

  13. Effect of irradiation on acrylic cement with special reference to fixation of pathological fractures. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Eftekhar, N.S.; Thurston, C.W.

    1975-01-01

    Self-curing cement is generally used in conjunction with conventional metallic devices. If the acrylic cement was supplemented, the primary goal would be a rigid immobiliztion of the fracture to alleviate the pain; usually, however, the final aim is toward osteosynthesis. During the course of rehabilitation, it is often desirous to supplement the treatment by irradiation. Although the industrial, dental and surgical literature has adequately dealt with many aspects of bone cement; for example, physical and chemical properties in joint replacement, and so on, the effects of irradiation on the acrylic cement have not been previously reported. It is the purpose of this paper to analyze the experimental studies conducted to evaluate the mechanical properties of the polymethylmethacrylate when subjected to irradiation within a maximum range of a therapeutic dose.

  14. Mechanical characterization of a short fiber-reinforced polymer at room temperature: experimental setups evaluated by an optical measurement system

    Science.gov (United States)

    Röhrig, C.; Scheffer, T.; Diebels, S.

    2017-09-01

    Composite materials are of great interest for industrial applications because of their outstanding properties. Each composite material has its own characteristics due to the large number of possible combinations of matrix and filler. As a result of their compounding, composites usually show a complex material behavior. This work is focused on the experimental testing of a short fiber-reinforced thermoplastic composite at room temperature. The characteristic behavior of this material class is often based on a superposition of typical material effects. The predicted characteristic material properties such as elasto-plasticity, damage and anisotropy of the investigated material are obtained from results of cyclic uniaxial tensile tests at constant strain rate. Concerning the manufacturing process as well as industrial applications, the experimental investigations are extended to multiaxial loading situations. Therefore, the composite material is examined with a setup close to a deep-drawing process, the Nakajima test (Nakazima et al. in Study on the formability of steel sheets. Yawate Technical Report No. 264, pp 8517-8530, 1968). The evaluation of the experimental investigations is provided by an optical analysis system using a digital image correlation software. Finally, based on the results of the uniaxial tensile tests, a one-dimensional macroscopic model is introduced and first results of the simulation are provided.

  15. Bond strength test of acrylic artificial teeth with prosthetic base

    Directory of Open Access Journals (Sweden)

    Erna Kurnikasari

    2008-07-01

    Full Text Available Denture consists of acrylic artificial teeth and acrylic prothesis base bond chemically with a bond strength of 315 kgF/cm2. Most of the commercial acrylic artificial teeth do not specify their specifications and all of those acrylic artificial teeth do not include mechanical data (bond strength. The aim of this study is to discover which acrylic artificial teeth meet ADA specification no. 15. This study is a descriptive analytic study performed to 5 acrylic artificial teeth posterior brands commonly used by dentists and technicians. From each brand, 3 sample teeth were taken. The acrylic artificial teeth were prepared into a rectangular shape and were attached between acrylic prothesis base simulation and jigs. The sample was given tensile load using a Universal Testing Machine. The amount of force that causes the teeth to be fractured was recorded and the bond strength was calculated. The results of the study show that the average value for the five acrylic artificial teeth for the five brands were as followed: Brand A, 125.993 kgF/cm2; B, 188.457 kgF/cm2; C, 175.880 kgF/cm2; D, 153.373 kgF/cm2; E, 82.839 kgF/cm2. The data can be tested statistically by using One Way ANOVA test and Dunnett test (alpha = 0.05. From the study, it is concluded that the five acrylic artificial teeth have a bond strength below the ADA specification no. 15.

  16. Allergic contact dermatitis from acrylic nails in a flamenco guitarist.

    Science.gov (United States)

    Alcántara-Nicolás, F A; Pastor-Nieto, M A; Sánchez-Herreros, C; Pérez-Mesonero, R; Melgar-Molero, V; Ballano, A; De-Eusebio, E

    2016-12-01

    Acrylates are molecules that are well known for their strong sensitizing properties. Historically, many beauticians and individuals using store-bought artificial nail products have developed allergic contact dermatitis from acrylates. More recently, the use of acrylic nails among flamenco guitarists to strengthen their nails has become very popular. A 40-year-old non-atopic male patient working as a flamenco guitarist developed dystrophy, onycholysis and paronychia involving the first four nails of his right hand. The lesions were confined to the fingers where acrylic materials were used in order to strengthen his nails to play the guitar. He noticed improvement whenever he stopped using these materials and intense itching and worsening when he began reusing them. Patch tests were performed and positive results obtained with 2-hydroxyethyl methacrylate (2-HEMA), 2-hydroxyethyl acrylate (2-HEA), ethyleneglycol-dimethacrylate (EGDMA) and 2-hydroxypropyl methacrylate (2-HPMA). The patient was diagnosed with occupational allergic contact dermatitis likely caused by acrylic nails. Artificial nails can contain many kinds of acrylic monomers but most cases of contact dermatitis are induced by 2-HEMA, 2-HPMA and EGDMA. This is the first reported case of occupational allergic contact dermatitis from acrylates in artificial nails in a professional flamenco guitar player. Since the practice of self-applying acrylic nail products is becoming very popular within flamenco musicians, we believe that dermatology and occupational medicine specialists should be made aware of the potentially increasing risk of sensitization from acrylates in this setting. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Synthesis, characterization, and swelling behaviors of salt-sensitive maize bran-poly(acrylic acid) superabsorbent hydrogel.

    Science.gov (United States)

    Zhang, Mingyue; Cheng, Zhiqiang; Zhao, Tianqi; Liu, Mengzhu; Hu, Meijuan; Li, Junfeng

    2014-09-03

    A novel composite hydrogel was prepared via UV irradiation copolymerization of acrylic acid and maize bran (MB) in the presence of composite initiator (2,2-dimethoxy-2-phenylacetophenone and ammonium persulfate) and cross-linker (N,N'-methylenebis(acrylamide)). Under the optimized conditions, maize bran-poly(acrylic acid) was obtained (2507 g g(-1) in distilled water and 658 g g(-1) in 0.9 wt % NaCl solution). Effects of granularity, salt concentration, and various cations and anions on water absorbency were investigated. It was found that swelling was extremely sensitive to the ionic strength and cation and anion type. Swelling kinetics and water diffusion mechanism in distilled water were also discussed. Moreover, the product showed excellent water retention capability under the condition of high temperature or high pressure. The salt sensitivity, good water absorbency, and excellent water retention capability of the hydrogels give this intelligentized polymer wide potential applications.

  18. Acrylic acid removal by acrylic acid utilizing bacteria from acrylonitrile-butadiene-styrene resin manufactured wastewater treatment system.

    Science.gov (United States)

    Wang, C C; Lee, C M

    2006-01-01

    The aim of this study is to isolate the acrylic acid utilizing bacteria from the ABS resin manufactured wastewater treatment system. The bacteria should have the ability to remove acrylic acid and tolerate the acrylonitrile and acrylamide toxicity. The aim is also to understand the performance of isolated pure strain for treating different initial acrylic acid concentrations from synthetic wastewater. The results are: twenty strains were isolated from the ABS resin manufactured wastewater treatment system and twelve of them could utilize 600 mg/l acrylic acid for growth. Seven of twelve strains could tolerate the acrylonitrile and acrylamide toxicity, when the concentration was below 300 mg/l. Bacillus thuringiensis was one of the seven strains and the optimum growth temperature was 32 degrees C. Bacillus thuringiensis could utilize acrylic acid for growth, when the initial acrylic acid concentration was below 1,690.4 mg/l. Besides this, when the initial acrylic acid concentration was below 606.8 mg/l, the acrylic acid removal efficiency exceeded 96.3%. Bacillus thuringiensis could tolerate 295.7 mg/l acrylamide and 198.4 mg/l acrylonitrile toxicity but could not tolerate 297.3 mg/l epsilon-caprolactam.

  19. Comparison of the Retinal Straylight in Pseudophakic Eyes with PMMA, Hydrophobic Acrylic, and Hydrophilic Acrylic Spherical Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Ya-wen Guo

    2014-01-01

    Full Text Available Purpose. To investigate the intraocular straylight value after cataract surgery. Methods. In this study, 76 eyes from 62 patients were subdivided into three groups. A hydrophobic acrylic, a hydrophilic acrylic, and a PMMA IOL were respectively, implanted in 24 eyes, 28 eyes, and 24 eyes. Straylight was measured using C-Quant at 1 week and 1 month postoperatively in natural and dilated pupils. Results. The hydrophilic acrylic IOLs showed significantly lower straylight values than those of the hydrophobic acrylic IOLs in dilated pupils at 1 week and 1 month after surgery (P0.05. Moreover, no significant difference was found in straylight between natural and dilated pupils in each group at 1 week and 1 month postoperatively (P>0.05. Conclusions. Although the hydrophobic acrylic IOL induced more intraocular straylight, straylight differences among the 3 IOLs were minimal. Pupil size showed no effect on intraocular straylight; the intraocular straylight was stable 1 week after surgery.

  20. Effect of adding Matrix Metallo proteinase inhibitors on the degree of conversion of monomers to polymer an experimental bonding agent

    Directory of Open Access Journals (Sweden)

    Ghavam M.

    2009-11-01

    Full Text Available "nBackground and Aim: In spite of the achievements in the field of dental adhesives, we are facing challenges with dentine bonding resistance, strength and stability. According to recent studies the role of MMP inhibitors in association with bonding,s persistence and leakage reduction and restoration,s persistence is important. The aim of this study was to investigate the effect of doxycycline as a MMP inhibitor on the degree of conversion (DC of an experimental dental adhesive. "nMaterials and Methods: In this experimental study, a new dental adhesive blend was prepared by mixing doxycycline monohydrate (in concentrations of 0.0, 0.25, 0.5, and 1 wt.% with monomers. The monomers were composed of 12% Bis-GMA and 10% TMPTMA, 28% HEMA, and 50% Ethanol by weight for all groups. Comphorquinone and amines were chosen as photo initiator system. Degree of conversion of all adhesives was measured using FTIR spectroscopy. The results were analyzed using one-way ANOVA and Tukey post hoc tests. "nResults: The results showed that addition of 0.25, 0.5, and 1 weight percent doxycycline did not significantly reduce the DC of the adhesives compared to 0.0% control group (p>0.05%. "nConclusion: According to the results of this study, adding doxycycline to the adhesives did not adversely affect the DC.

  1. Investigation of small molecular weight poly(acrylic acid) adsorption on γ-alumina

    Science.gov (United States)

    Liu, Lei; Luo, Shi-Zhong; Wang, Bin; Guo, ZhanHu

    2015-08-01

    The interactions between poly(acrylic acid) (PAA) and alumina have been widely investigated. In this study, the pattern of small molecular weight PAA (MW 3000) interaction with γ-alumina has been dissected. The alumina/PAA hybrids were prepared at pH 4.0, 5.5, and 7.0, respectively. Nitrogen absorption-desorption analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and elemental analysis were conducted to illustrate the characteristics of the hybrids. At pH 4.0, the coiled PAA conformation yielded polymer adsorption primarily on alumina outer surface. At higher pH values, the more stretched PAA molecules were able to infiltrate inside the alumina pores. The phenomenon is explained by the polymer chain reptation motion model. Coiled polymer chains are not oriented enough to penetrate the oxide pore channels. In contrary, stretched polymer chains are more likely to move along the pore channels.

  2. Thermoresponsive Photonic Crystal: Synergistic Effect of Poly(N-isopropylacrylamide)-co-acrylic Acid and Morpho Butterfly Wing.

    Science.gov (United States)

    Xu, Dongdong; Yu, Huanan; Xu, Qun; Xu, Guiheng; Wang, Kaixi

    2015-04-29

    In this work, we report a simple method to fabricate smart polymers engineered with hierarchical photonic structures of Morpho butterfly wing to present high performance that are capable of color tunability over temperature. The materials were assembled by combining functional temperature responsivity of poly(N-isopropylacrylamide)-co-acrylic acid (PNIPAm-co-AAc) with the biological photonic crystal (PC) structure of Morpho butterfly wing, and then the synergistic effect between the functional polymer and the natural PC structure was created. Their cooperativity is instantiated in the phase transition of PNIPAm-co-AAc (varying with the change of temperature) that can alter the nanostructure of PCs, which further leads to the reversible spectrum response property of the modified hierarchical photonic structures. The cost-effective biomimetic technique presented here highlights the bright prospect of fabrication of more stimuli-responsive functional materials via coassembling smart polymers and biohierarchical structures, and it will be an important platform for the development of nanosmart biomaterials.

  3. Fast and Efficient [2+2] UV Cycloaddition for Polymer Modification via Flow Synthesis

    OpenAIRE

    CONRADI, Matthias Horst; Junkers, Thomas

    2014-01-01

    The alkene enone [2 + 2] photocycloaddition reaction between polymer-bound maleimide and functional alkenes has been tested in a UV-flow reactor, demonstrating a very high efficiency of the reaction. As a test reaction, polymer end group modifications were carried out on maleimide-functional poly(butyl acrylate). The polymer was prepared by atom transfer radical polymerization (ATRP) using a N-hydroxysuccinimide-functionalized initiator, followed by exchange reaction of the activated ester wi...

  4. Development of carboxymethyl cellulose acrylate for various biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Kunal [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Banthia, A K [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Majumdar, D K [Delhi Institute of Pharmaceutical Sciences and Research, Formerly College of Pharmacy, University of Delhi, Pushp Vihar, Sector III, New Delhi 110017 (India)

    2006-06-15

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.

  5. Development of carboxymethyl cellulose acrylate for various biomedical applications

    Science.gov (United States)

    Pal, Kunal; Banthia, A. K.; Majumdar, D. K.

    2006-06-01

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.

  6. Biodegradable Polymers

    OpenAIRE

    Isabelle Vroman; Lan Tighzert

    2013-01-01

    Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

  7. An epidemic of occupational contact dermatitis from an acrylic glue.

    Science.gov (United States)

    Kiec-Swierczynska, Marta; Krecisz, Beata; Swierczynska-Machura, Dominika; Zaremba, Joanna

    2005-03-01

    Dermatological examinations were performed in 81 workers involved in the manufacture of electric coils for television displays, who had worked for 4 years in contact with a glue containing isobornyl acrylate, acrylic acid, N,N dimethyleneacrylamide, phosphine oxide, bis(2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl)- and beta-carboxyethyl acrylate. The glue was cured by 350-500-nm ultraviolet and visible radiations. Acrylate-specific dermal lesions were detected in 21 (25.9%) people. Occupational irritant contact dermatitis was diagnosed in 12 (15%) of the workers and occupational allergic contact dermatitis in 9 (11.2%). 12 people reacted to acrylates. Cross-reactions with methacrylates were not observed. The highest number of positive tests was obtained with triethyleneglycol diacrylate (10 people) and diethyleneglycol diacrylate (9), followed by 1,6-hexanediol diacrylate (5), 1,4-butanediol diacrylate (4), beta-carboxyethyl acrylate (3), tripropyleneglycol diacrylate (2) and pentaerythritol triacrylate (2). No cases of allergy to isobornyl acrylate, N,N-methylenebisacrylamide or phosphine oxide were noted.

  8. COMPARATIVE ANALYSIS OF WATER SORPTION BY DIFFERENT ACRYLIC MATERIALS

    Directory of Open Access Journals (Sweden)

    Milena Kostić

    2014-06-01

    Full Text Available Acrylic materials are used daily for the production of mobile dental restorations and orthodontic appliances. The presence of residual monomer, as a product of incomplete polymerisation of material, results in more porous structure of the material, which greatly reduces the mechanical and physical quality of the acrylic restorations and increases the absorption of liquids. The aim of this study was to examine the water absorption of different types of resin material. In the study it was assumed that the cold polymerized acrylates show a greater potential for absorbing fluid from the environment in relation to the hot polymerized acrylic. The study included two hot and two cold polymerized acrylates, and cold polymerized acrylate impregnated with aesthetic pearls. In order to determine the degree of water absorption, the mass of the samples was measured before and after one day, seven days and thirty days of immersion in a water bath of body temperature. The tested hot and cold polymerized acrylates after immersion in water bath showed standard values of water absorption. The degree of water absorption was not significantly influenced by the type and manner of polymerisation. Water absorption values were significantly higher after seven days and thirty days of water storage relative to the observational period of one day.

  9. Molecular level dispersion of graphene in polymer matrices using colloidal polymer and graphene.

    Science.gov (United States)

    Gudarzi, Mohsen Moazzami; Sharif, Farhad

    2012-01-15

    A novel and environmentally friendly method based on mixing of colloidal polymer particles and graphene sheets has been developed. It is found that colloidal polymers can be employed to stabilize graphene oxide (GO) sheets during reduction to graphene. Adsorption of polymer particles at the surface of graphene layers seems to be underlying mechanism of stabilization of graphene sheets. Surface polarity of the polymer particles is crucial for the successful stabilization of graphene layers. Presence of colloidal particles at the surface of graphene prohibits restacking and agglomeration of nanolayers, resulting in fine dispersion of graphene throughout the polymeric matrix. Formation of strong bond between polar segments of the polymer chain and oxygen groups of graphene sheets generates a strong interface improving final properties of the composites. Inclusion of merely 2 wt% of graphene into an acrylic resin resulted in an increase of 522% and 242% in modulus and hardness, respectively. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Preparation of porous carboxymethyl chitosan grafted poly (acrylic acid) superabsorbent by solvent precipitation and its application as a hemostatic wound dressing.

    Science.gov (United States)

    Chen, Yu; Zhang, Yong; Wang, Fengju; Meng, Weiwei; Yang, Xinlin; Li, Peng; Jiang, Jianxin; Tan, Huimin; Zheng, Yongfa

    2016-06-01

    The volume phase transition of a hydrogel initiated by shrinking may result in complex patterns on its surface. Based on this unique property of hydrogel, we have developed a novel solvent precipitation method to prepare a kind of novel superabsorbent polymers with excellent hemostatic properties. A porous carboxymethyl chitosan grafted poly (acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared by precipitating CMCTS-g-PAA hydrogel with ethanol. Its potential application in hemostatic wound dressing was investigated. The results indicate that the modified superabsorbent polymer is non-cytotoxic. It showed a high swelling capacity and better hemostatic performance in the treatments of hemorrhage model of ear artery, arteria cruralis and spleen of the New Zealand white rabbit than the unmodified polymer and other commonly used clinic wound dressings. The hemostatic mechanism of the porous CMCTS-g-PAA polymer was also discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Chemo-enzymatic synthesis route to poly(glucosyl-acrylates) using glucosidase from almonds

    NARCIS (Netherlands)

    Kloosterman, Wouter M. J.; Roest, Steven; Priatna, Siti R.; Stavila, Erythrina; Loos, Katja

    2014-01-01

    Novel types of glucosyl-acrylate monomers are obtained by beta-glucosidase from almond catalyzed glycosidation reaction. The saccharide-acrylate monomers were synthesized by reaction of D-glucose with hydroxyl functional acrylates: 2-hydroxyethyl acrylate (2-HEA), 2-hydroxyethyl methacrylate

  12. The sensitizing potential of 2-ethylhexyl acrylate in the guinea pig.

    Science.gov (United States)

    Waegemaekers, T H; van der Walle, H B

    1983-09-01

    The sensitizing potential of 2-ethylhexyl acrylate in the guinea pig could be demonstrated by Freund's Complete Adjuvant Test. This acrylate ester is a common constituent of adhesive tape. Allergic reactions to several brands of adhesive tape were not observed in 2-ethylhexyl acrylate sensitized animals. Cross reactions with other acrylic monomers were observed.

  13. 21 CFR 177.1990 - Vinylidene chloride/methyl acrylate copolymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Vinylidene chloride/methyl acrylate copolymers. 177... chloride/methyl acrylate copolymers. The vinylidene chloride/methyl acrylate copolymers (CAS Reg. No. 25038...) Identity. For the purposes of this section vinylidene chloride/methyl acrylate copolymers consist of basic...

  14. Experimental and Simulated Investigations of Thin Polymer Substrates with an Indium Tin Oxide Coating under Fatigue Bending Loadings

    Directory of Open Access Journals (Sweden)

    Jiong-Shiun Hsu

    2016-08-01

    Full Text Available Stress-induced failure is a critical concern that influences the mechanical reliability of an indium tin oxide (ITO film deposited on a transparently flexible polyethylene terephthalate (PET substrate. In this study, a cycling bending mechanism was proposed and used to experimentally investigate the influences of compressive and tensile stresses on the mechanical stability of an ITO film deposited on PET substrates. The sheet resistance of the ITO film, optical transmittance of the ITO-coated PET substrates, and failure scheme within the ITO film were measured to evaluate the mechanical stability of the concerned thin films. The results indicated that compressive and tensile stresses generated distinct failure schemes within an ITO film and both led to increased sheet resistance and optical transmittance. In addition, tensile stress increased the sheet resistance of an ITO film more easily than compressive stress did. However, the influences of both compressive and tensile stress on increased optical transmittance were demonstrated to be highly similar. Increasing the thickness of a PET substrate resulted in increased sheet resistance and optical transmittance regardless of the presence of compressive or tensile stress. Moreover, J-Integral, a method based on strain energy, was used to estimate the interfacial adhesion strength of the ITO-PET film through the simulation approach enabled by a finite element analysis.

  15. Occupational contact dermatitis to acrylates in a manicurist.

    Science.gov (United States)

    Kiec-Swierczynska, M; Krecisz, B; Chomiczewska-Skora, D

    2013-07-01

    We report the case of a manicurist who developed an allergic skin reaction to acrylates, manifested by bullous lesions on fingertips and eczema of the hands and ears. Patch tests showed positive reactions to 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, ethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate, 1,6-hexandiol diacrylate, 2-hydroxyethyl acrylate and triethyleneglycol diacrylate. Because of her skin disorder, she had to give up her job. She was not correctly advised on retraining and started to work as a dental nurse. Soon after re-exposure to acrylates in dental materials, she experienced recurrence of the skin symptoms.

  16. Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate

    Energy Technology Data Exchange (ETDEWEB)

    Binder, Thomas [Archer Daniels Midland Company, Decatur, IL (United States); Erpelding, Michael [Archer Daniels Midland Company, Decatur, IL (United States); Schmid, Josef [Archer Daniels Midland Company, Decatur, IL (United States); Chin, Andrew [Archer Daniels Midland Company, Decatur, IL (United States); Sammons, Rhea [Archer Daniels Midland Company, Decatur, IL (United States); Rockafellow, Erin [Archer Daniels Midland Company, Decatur, IL (United States)

    2015-04-10

    Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate. The purpose of Archer Daniels Midlands Integrated Biorefinery (IBR) was to demonstrate a modified acetosolv process on corn stover. It would show the fractionation of crop residue to distinct fractions of cellulose, hemicellulose, and lignin. The cellulose and hemicellulose fractions would be further converted to ethanol as the primary product and a fraction of the sugars would be catalytically converted to acrylic acid, with butyl acrylate the final product. These primary steps have been demonstrated.

  17. Bond strength of stainless steel orthodontic brackets bonded to prefabricated acrylic teeth.

    Science.gov (United States)

    Wan Abdul Razak, Wan Salbiah; Sherriff, Martyn; Bister, Dirk; Seehra, Jadbinder

    2017-06-01

    The purpose of this in-vitro study was to evaluate the force to debond stainless steel orthodontic brackets bonded to acrylic teeth using different combinations of adhesive and surface treatments. One hundred prefabricated upper lateral incisor acrylic teeth were divided into 4 equal groups: Transbond XT® adhesive only (Group 1, control), Transbond XT® adhesive with sandblasting (Group 2), Transbond XT® adhesive with abrasion / + methyl methacrylate (MMA) (Group 3) and Triad® Gel only (Group 4). The force in Newtons (N) to debond the brackets was measured. One-way analysis of variance (ANOVA) and pairwise multi-comparison of means (Šidak's adjustment) were undertaken. The highest force to debond was recorded for Group 2 (275.7 N; SD 89.0) followed by Group 3 (241.9 N; SD 76.0), Group 1 (142.7 N; SD 36.7) and Group 4 (67.9 N; SD 21.1). Significant differences in bond strength measurements between the experimental groups were detected. Mean force values for the groups revealed no significant differences between Group 2 and Group 3 (p>0.05). Both sandblasting and surface abrasion/+ application of methyl methacrylate (MMA) in combination with Transbond XT® adhesive are recommended for bonding stainless orthodontic brackets to acrylic teeth.

  18. IN VITRO ANTIFUNGAL ACTION OF DIFFERENT SUBSTANCES OVER MICROWAVED-CURED ACRYLIC RESINS

    Science.gov (United States)

    Montagner, Henrique; Montagner, Francisco; Braun, Katia Olmedo; Peres, Paulo Edelvar Correa; Gomes, Brenda Paula Figueiredo de Almeida

    2009-01-01

    Objective: The presence of Candida albicans on the surfaces of denture-base acrylic resins is strongly related to the development of oral stomatitis. This study evaluated the antifungal action of different agents over microwave-cured acrylic resin without polishing specimens previously contaminated with Candida albicans. Material and Methods: Sixty specimens were immersed in BHI broth previously inoculated with the yeast and stored for 3 h at 37°C. They were divided into 5 experimental groups (n=10): G1: 2% chlorhexidine solution (10 min); G2: 0.5% sodium hypochlorite (10 min); G3: modified sodium hypochlorite (10 min); G4: effervescent agent (5 min); G5: hydrogen peroxide 10v (30 min). The specimens of the control group 1 (C1) were not disinfected. Ten additional specimens of the control group 2 (C2) were not infected with the yeast, aiming to check the asepsis during the experiment. The disinfection agents were neutralized and the acrylic resin specimens were immersed in BHI Broth for 24 h. Culture media turbidity was evaluated spectrophotometrically according to the transmittance degree, i.e. the higher the transmittance the stronger the antimicrobial action. Statistical analysis was performed (Kruskal-Wallis Test, psodium hypochlorite-based substances and hydrogen peroxide are more efficient disinfectants against C. albicans than 2% chlorhexidine solution and the effervescent agent. PMID:19936521

  19. In vitro antifungal action of different substances over microwaved-cured acrylic resins.

    Science.gov (United States)

    Montagner, Henrique; Montagner, Francisco; Braun, Katia Olmedo; Peres, Paulo Edelvar Correa; Gomes, Brenda Paula Figueiredo de Almeida

    2009-01-01

    The presence of Candida albicans on the surfaces of denture-base acrylic resins is strongly related to the development of oral stomatitis. This study evaluated the antifungal action of different agents over microwave-cured acrylic resin without polishing specimens previously contaminated with Candida albicans. Sixty specimens were immersed in BHI broth previously inoculated with the yeast and stored for 3 h at 37 degrees C. They were divided into 5 experimental groups (n=10): G1: 2% chlorhexidine solution (10 min); G2: 0.5% sodium hypochlorite (10 min); G3: modified sodium hypochlorite (10 min); G4: effervescent agent (5 min); G5: hydrogen peroxide 10 v (30 min). The specimens of the control group 1 (C1) were not disinfected. Ten additional specimens of the control group 2 (C2) were not infected with the yeast, aiming to check the asepsis during the experiment. The disinfection agents were neutralized and the acrylic resin specimens were immersed in BHI Broth for 24 h. Culture media turbidity was evaluated spectrophotometrically according to the transmittance degree, i.e. the higher the transmittance the stronger the antimicrobial action. Statistical analysis was performed (Kruskal-Wallis Test, pdisinfectants against C. albicans than 2% chlorhexidine solution and the effervescent agent.

  20. Controlling the nano-deformation of polymer by a reversible photo-cross-linking reaction

    Science.gov (United States)

    Van-Pham, Dan-Thuy; Nguyen, Minh Tri; Ohdomari, Ken; Nakanishi, Hideyuki; Norisuye, Tomohisa; Tran-Cong-Miyata, Qui

    2017-06-01

    The reaction-induced deformation and its recovery process in the nanometer scale of a photo-cross-linkable poly(ethyl acrylate) were in situ studied by using Mach-Zehnder interferometry. The ON-OFF modulated irradiation using two different UV wavelengths, 365 nm and 297 nm, was carried out to elucidate the effects of the reversible cross-link on the deformation kinetics of the polymer. It was found that the irradiation time-dependence of the crosslink density generated during the ON-OFF irradiation process deviates from the data obtained by continuous irradiation process, revealing the relaxation effect of the forming poly(ethyl acrylate) networks in the dark during each irradiation cycle. Furthermore, the recovery of the sample thickness can be achieved by photodissociation of the anthracene photodimers by irradiating the cross-linked sample with 297 nm UV light. These experimental results reveal the possibility of reversible control the shrinkage and swelling proceses of a polymeric film by using the photodimerization of anthracene.

  1. [Determination of 9 residual acrylic monomers in acrylic resins by gas chromatography-mass spectrometry coupled with microwave assisted extraction].

    Science.gov (United States)

    Lai, Ying; Lin, Rui; Cai, Luxin; Ge, Xiuxiu; Huang, Changchun

    2012-01-01

    A reliable gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of 9 residual acrylic monomers (methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl acrylate, butyl methacrylate, styrene, acrylic acid and methacrylic acid) in acrylic resins. Solid resin was precipitated with methanol after microwave assisted extraction with ethyl acetate for 30 min, and liquid resin was diluted with methanol directly. The nine acrylic monomers got a good separation within 20 min on a DB-WAX column. The limits of quantification (LOQs, S/N = 10) of the method were in the range of 1-10 mg/kg for liquid resin and 3-50 mg/kg for solid resin. The calibration curves were linear within 1-500 mg/L range with correlation coefficients above 0. 995. The recoveries ranged from 84.4% to 108.6% at five spiked levels. The sensitivity, recovery and selectivity of the method can fully meet the requirements of practical work.

  2. Experimental Method of Temperature and Strain Discrimination in Polymer Composite Material by Embedded Fiber-Optic Sensors Based on Femtosecond-Inscribed FBGs

    Directory of Open Access Journals (Sweden)

    Victor V. Shishkin

    2016-01-01

    Full Text Available Experimental method of temperature and strain discrimination with fiber Bragg gratings (FBGs sensors embedded in carbon fiber-reinforced plastic is proposed. The method is based on two-fiber technique, when two FBGs inscribed in different fibers with different sensitivities to strain and/or temperature are placed close to each other and act as a single sensing element. The nonlinear polynomial approximation of Bragg wavelength shift as a function of temperature and strain is presented for this method. The FBGs were inscribed with femtosecond laser by point-by-point inscription technique through polymer cladding of the fiber. The comparison of linear and nonlinear approximation accuracies for array of embedded sensors is performed. It is shown that the use of nonlinear approximation gives 1.5–2 times better accuracy. The obtained accuracies of temperature and strain measurements are 2.6–3.8°C and 50–83 με in temperature and strain range of 30–120°C and 0–400 με, respectively.

  3. Comparison of Numerical and Experimental Studies for Flow-Field Optimization Based on Under-Rib Convection in Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Nguyen Duy Vinh

    2016-10-01

    Full Text Available The flow-field design based on under-rib convection plays an important role in enhancing the performance of polymer electrolyte membrane fuel cells (PEMFCs because it ensures the uniform distribution of the reacting gas and the facilitation of water. This research focused on developing suitable configurations of the anode and cathode bipolar plates to enhance the fuel cell performance based on under-rib convection. The work here evaluated the effects of flow-field designs, including a serpentine flow field with sub channel and by pass and a conventional serpentine flow-field on single-cell performance. Both the experiment and computer simulation indicated that the serpentine flow field with sub channel and by pass (SFFSB configuration enables more effective utilization of the electrocatalysts since it improves reactant transformation rate from the channel to the catalyst layer, thereby dramatically improving the fuel cell performance. The simulation and experimental results indicated that the power densities are increased by up to 16.74% and 18.21%, respectively, when applying suitable flow-field configurations to the anode and cathode bipolar plates. The findings in this are the foundation for enhancing efficient PEMFCs based on flow field design.

  4. Microwave irradiation as an alternative method for disinfection of denture base acrylic resins.

    Science.gov (United States)

    Silva, M; Consani, R; Sardi, J; Mesquita, M; Macêdo, A; Takahashi, J

    2013-01-01

    This study evaluated the effect of microwave irradiation as an alternative method for disinfection of different types of denture base acrylic resins. Twenty-four samples for each conventional, microwaved and characterized heat-cured acrylic resin were made and subjected to sterilization with ethylene oxide for the groups: 1) irradiated samples; 2) non-irradiated samples; and 3) samples without yeast. Each group was subdivided according to inoculation with C. albicans, C. dubliniensis and C. tropicalis. The samples were inoculated with 100 µL of inoculum of each species of Candida and later placed in an incubator at 37 °C for 1 hr to perform the first adhesion. After this time, each well was supplemented with sterile media and the plate was once again taken to a stove for incubation at 37 °C for 6 hr. The samples were immersed in 100 mL of sterile water and irradiated with microwave at 650 W for 3 min. Control samples were considered as the non-irradiated group. After incubation for 48 hr, irradiated and non-irradiated samples were subjected to a digital colony counter. Control group (non-irradiated) showed microbial growth for resins and the means of ufc/mL were without statistically significant differences. Microwave irradiated samples (experimental group) promoted no viable colonies for all Candida species and types of acrylic resins. The means of ufc/mL were without statistically significant differences. Microwave irradiation was an effective method for disinfection of the acrylic resins inoculated with C. albicans, C. dubliniensis and C. tropicalis.

  5. ET-37EFFICACY OF INTRACRANIAL DELIVERY OF DICHLOROACETATE AND CARBOPLATIN VIA AN LCP POLYMER MICROCAPSULE DEVICE IN AN EXPERIMENTAL GLIOMA MODEL

    Science.gov (United States)

    Mangraviti, Antonella; Jin, Yike; Sy, Jay; Wang, Yuan; Raghavan, Tula; Hastings-Spaine, Lindsey; Olivi, Alessandro; Tyler, Betty; Brem, Henry

    2014-01-01

    BACKGROUND: Multi-targeted therapy is a promising strategy for patients with glioblastoma and controlled delivery of these chemotherapeutics is crucial for effective intracranial chemotherapy. Studies combining platinum pharmacophores with apoptosis inducers, such as Dichloroacetae (DCA), suggest that DCA enhances the sensitivity of cancer cells to platinum compounds. We assessed the efficacy of DCA in combination with Carboplatin (CB) delivered from a biocompatible liquid crystal polymer (LCP) microcapsule in an experimental glioma model in rats. METHODS: In vitro studies were performed to assess the cytotoxicity of DCA and CB on F98 rodent glioma cells. Efficacy was assessed in vivo in rats with intracranially implanted F98 with intracranial implantation of 50% DCA and 5% CB wafers, in monotherapy and in combination. A second study assessed the efficacy of DCA and CB released from an LCP microcapsule as a multi-drug delivery device. RESULTS: The IC50 values for DCA and CB at 24 hours were 70mM and 39mM(R2 =0.989 and 0.948, respectively). The initial efficacy study showed no difference in median survival between the control group and either DCA or CB monotherapy treatments. However, the animals that received CB wafer in combination with DCA wafer had significantly increased survival as compared to the control group (p = 0.016). The microcapsule efficacy study showed that animals given intracranial LCP microcapsule loaded with 5% CB/pCPP:SA and 50% DCA/pCPP:SA had significant improvement in survival (p= 0.0042 vs. control). CONCLUSION: We show that the intracranial delivery of Dichloroacetate and Carboplatin significantly increases survival in an experimental glioma model, when delivered via polymeric wafer as well as when delivered from LCP microcapsule. The LCP microcapsule is a safe and effective method for intracranial dual-drug delivery and may be a novel strategy for obtaining controlled release of multiple drugs with drug-specific kinetics and independent

  6. Effect of post-polymerization heat treatments on the cytotoxicity of two denture base acrylic resins.

    Science.gov (United States)

    Jorge, Janaina Habib; Giampaolo, Eunice Teresinha; Vergani, Carlos Eduardo; Machado, Ana Lúcia; Pavarina, Ana Cláudia; Carlos, Iracilda Zeppone

    2006-06-01

    Most denture base acrylic resins have polymethylmethacrylate in their composition. Several authors have discussed the polymerization process involved in converting monomer into polymer because adequate polymerization is a crucial factor in optimizing the physical properties and biocompatibility of denture base acrylic resins. To ensure the safety of these materials, in vitro cytotoxicity assays have been developed as preliminary screening tests to evaluate material biocompatibility. (3)H-thymidine incorporation test, which measures the number of cells synthesizing DNA, is one of the biological assays suggested for cytotoxicity testing. The purpose of this study was to investigate, using (3)H-thymidine incorporation test, the effect of microwave and water-bath post-polymerization heat treatments on the cytotoxicity of two denture base acrylic resins. Nine disc-shaped specimens (10 x 1 mm) of each denture base resin (Lucitone 550 and QC 20) were prepared according to the manufacturers' recommendations and stored in distilled water at 37 degrees C for 48 h. The specimens were assigned to 3 groups: 1) post-polymerization in a microwave oven for 3 min at 500 W; 2) post-polymerization in water-bath at 55 degrees C for 60 min; and 3) without post-polymerization. For preparation of eluates, 3 discs were placed into a sterile glass vial with 9 mL of Eagle's medium and incubated at 37 degrees C for 24 h. The cytotoxic effect of the eluates was evaluated by (3)H-thymidine incorporation. The results showed that the components leached from the resins were cytotoxic to L929 cells, except for the specimens heat treated in water bath (pmicrowave post-polymerization heat treatment.

  7. Electrically Conductive Multiphase Polymer Blend Carbon-Based Composites

    Science.gov (United States)

    Brigandi, Paul J.

    Electrically conductive polymer composites consisting of conductive fillers dispersed in polymer systems continue to attract increasing research. Multiphase polymer blends provide unique morphologies to reduce the percolation concentration and increase conductivity of carbon-based polymer composites. The goal of this research is to further the current understanding of electrically conductive ternary polymer blends. The overall purpose is to leverage this work to design composite materials that achieve increased conductivity at reduced conductive filler loadings that can be extended to applications requiring conductivity and a balance of additional properties. The first part of this research investigated the kinetic and thermodynamic effects on a series of multiphase conductive polymer composites. The electrical conductivity and phase morphology of a carbon black (CB) filled polypropylene (PP)/poly(methyl methacrylate) (PMMA)/ethylene acrylic acid copolymer (EAA) ternary polymer blend was determined as a function of compounding sequence and annealing time. The phase morphology and conductivity at short annealing times were influenced by the compounding sequence; however, they were thermodynamically driven at longer annealing times. The resistivity was found to decrease by a statistically significant amount to similar levels for all of the composite systems with increasing annealing time. The increase in conductivity at longer annealing times was determined to be the result of changes in the phase morphology from sea-island, dispersed microstructure to a tri-continuous morphology. The second part of this research studied the influence of CB and multiwall carbon nanotube (CNT) conductive fillers with different colloidal properties on the phase morphology, electrical properties, and rheological behavior in the PP/PMMA/EAA ternary polymer blend. A PP/PMMA/(EAA-CNT) system was compared to two different PP/PMMA/(EAA-CB) systems. The critical electrical percolation

  8. Supercritical water oxidation of acrylic acid production wastewater.

    Science.gov (United States)

    Gong, Y M; Wang, S Z; Tang, X Y; Xu, D H; Ma, H H

    2014-01-01

    Supercritical water oxidation (SCWO) of wastewater from an acrylic acid manufacturing plant has been studied on a continuous flow experimental system, whose reactor was made of Hastelloy C-276. Experimental conditions included a reaction temperature (T) ranging from 673 to 773K, a residence time (t) ranging from 72.7 to 339s, a constant pressure (P) of 25 MPa and a fixed oxidation coefficient (alpha) of 2.0. Experimental results indicated that reaction temperature and residence time had significant influences on the oxidation reaction, and increasing the two operation parameters could improve both degradation of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N). The COD removal efficiency could reach up to 98.73% at 25 MPa, 773 K and 180.1 s, whereas the destruction efficiency of NH3-N was only 43.71%. We further carried out a kinetic analysis considering the induction period through free radical chain mechanism. It confirms that the power-law rate equation for COD removal was 345 exp(-52200/RT)[COD]1.98[O2]0.17 and for NH3-N removal was 500 exp(-64492.19/RT)[NH3-N]1.87 [O2]0.03. Moreover, the induction time formulations for COD and NH3-N were suspected to be exp(38250/RT)/173 and exp(55690/RT)/15231, respectively. Correspondingly, induction time changed from 2.22 to 5.38 s for COD and 0.38 to 1.38 s for NH3-N. Owing to the catalysis of reactor inner wall surface, more than 97% COD removal was achieved in all samples.

  9. A stability study of plasma polymerized acrylic acid films

    Science.gov (United States)

    Cools, Pieter; Declercq, Heidi; De Geyter, Nathalie; Morent, Rino

    2018-02-01

    A medium pressure parallel-plate DBD set-up was used for the deposition of carboxylic acid-rich films using acrylic acid as precursor. A variety of discharge powers (21-33 W) and monomer flow rates (0.25-0.5 g/h) were applied to develop a range of coatings from highly unstable to completely stable in aqueous solutions. FT-IR and XPS were used to identify which coatings were stable under dynamic incubation conditions and what influence plasma operating parameters had on functional group preservation. White light interferometry was also used to calculate deposition rates (66-126 nm/min) and to determine the deposition regime (monomer deficient). Human foreskin fibroblasts were seeded onto the complete range of investigated samples and the effects of coating (in)stability on cell adhesion, viability and morphology were systematically studied. Results showed that the 27 W-0.25 g/h treatment conditions resulted in the most stable coatings. Although a concentration of only 0.7% of carboxylic acid groups was found under these experimental conditions, the positive effects of a highly acid-rich surface were still maintained as cell-material interactions were significantly enhanced.

  10. Fire-safe polymers and polymer composites

    Science.gov (United States)

    Zhang, Huiqing

    The intrinsic relationships between polymer structure, composition and fire behavior have been explored to develop new fire-safe polymeric materials. Different experimental techniques, especially three milligram-scale methods---pyrolysis-combustion flow calorimetry (PCFC), simultaneous thermal analysis (STA) and pyrolysis GC/MS---have been combined to fully characterize the thermal decomposition and flammability of polymers and polymer composites. Thermal stability, mass loss rate, char yield and properties of decomposition volatiles were found to be the most important parameters in determining polymer flammability. Most polymers decompose by either an unzipping or a random chain scission mechanism with an endothermic decomposition of 100--900 J/g. Aromatic or heteroaromatic rings, conjugated double or triple bonds and heteroatoms such as halogens, N, O, S, P and Si are the basic structural units for fire-resistant polymers. The flammability of polymers can also be successfully estimated by combining pyrolysis GC/MS results or chemical structures with TGA results. The thermal decomposition and flammability of two groups of inherently fire-resistant polymers---poly(hydroxyamide) (PHA) and its derivatives, and bisphenol C (BPC II) polyarylates---have been systematically studied. PHA and most of its derivatives have extremely low heat release rates and very high char yields upon combustion. PHA and its halogen derivatives can completely cyclize into quasi-polybenzoxazole (PBO) structures at low temperatures. However, the methoxy and phosphate derivatives show a very different behavior during decomposition and combustion. Molecular modeling shows that the formation of an enol intermediate is the rate-determining step in the thermal cyclization of PHA. BPC II-polyarylate is another extremely flame-resistant polymer. It can be used as an efficient flame-retardant agent in copolymers and blends. From PCFC results, the total heat of combustion of these copolymers or blends

  11. Emulsion Polymerization of Butyl Acrylate: Spin Trapping and EPR Study

    Science.gov (United States)

    Kim, S.; Westmoreland, D.

    1994-01-01

    The propagating radical in the emulsion polymerization reaction of butyl acrylate was detected by Electron Paramagnetic Resonance spectroscopy using two spin trapping agents, 2-methyl-2nitrosopropane and alpha -N-tert-butylnitrone.

  12. Synthesis and characterization of polycaprolactone/acrylic acid ...

    Indian Academy of Sciences (India)

    ... of polycaprolactone/acrylic acid (PCL/AA) hydrogel for controlled drug delivery ... by measuring diffusion coefficient () and equilibrium water content (EWC). Network formation, morphology and crystallinity of PCL/AA hydrogels were ...

  13. Performance behavior of modified cellulosic fabrics using polyurethane acrylate copolymer.

    Science.gov (United States)

    Zuber, Mohammad; Shah, Sayyed Asim Ali; Jamil, Tahir; Asghar, Muhammad Irfan

    2014-06-01

    The surface of the cellulosic fabrics was modified using self-prepared emulsions of polyurethane acrylate copolymers (PUACs). PUACs were prepared by varying the molecular weight of polycaprolactone diol (PCL). The PCL was reacted with isophorone diisocyanate (IPDI) and chain was extended with 2-hydroxy ethyl acrylate (HEA) to form vinyl terminated polyurethane (VTPU) preploymer. The VTPU was further co-polymerized through free radical polymerization with butyl acrylate in different proportions. The FT-IR spectra of monomers, prepolymers and copolymers assured the formation of proposed PUACs structure. The various concentrations of prepared PUACs were applied onto the different fabric samples using dip-padding techniques. The results revealed that the application of polyurethane butyl acrylate copolymer showed a pronounced effect on the tear strength and pilling resistance of the treated fabrics. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. [Treatment of acrylate wastewater by electrocatalytic reduction process].

    Science.gov (United States)

    Yu, Li-Na; Song, Yu-Dong; Zhou, Yue-Xi; Zhu, Shu-Quan; Zheng, Sheng-Zhi; Ll, Si-Min

    2011-10-01

    High-concentration acrylate wastewater was treated by an electrocatalytic reduction process. The effects of the cation exchange membrane (CEM) and cathode materials on acrylate reduction were investigated. It indicated that the acrylate could be reduced to propionate acid efficiently by the electrocatalytic reduction process. The addition of CEM to separator with the cathode and anode could significantly improve current efficiency. The cathode materials had significant effect on the reduction of acrylate. The current efficiency by Pd/Nickel foam, was greater than 90%, while those by nickel foam, the carbon fibers and the stainless steel decreased successively. Toxicity of the wastewater decreased considerably and methane production rate in the biochemical methane potential (BMP) test increased greatly after the electrocatalytic reduction process.

  15. Use of acrylic sheet molds for elastomeric products

    Science.gov (United States)

    Heisman, R. M.; Koerner, A. E.; Messineo, S. M.

    1970-01-01

    Molds constructed of acrylic sheet are more easily machined than metal, are transparent to ensure complete filling during injection, and have smooth surfaces free of contamination. Technique eliminates flashing on molded parts and mold release agents.

  16. Photocatalytic degradation of methyl orange using polymer-titania microcomposites.

    Science.gov (United States)

    Coutinho, Cecil A; Gupta, Vinay K

    2009-05-15

    Photodegradation of an organic dye was studied experimentally using novel polymer-titania microcomposites. These microcomposites were prepared from titanium dioxide (TiO(2)) nanoparticles embedded within cross-linked, thermally-responsive microgels of poly(N-isopropylacrylamide) and contained interpenetrating linear chains of poly(acrylic acid) that functionalize the nanoparticles of TiO(2). Because these microcomposites settle more than a hundred times faster than freely suspended TiO(2) nanoparticles, they are extremely useful for simple gravity separation of the photocatalyst in applications that employ titania nanoparticles. Methyl orange (MO) was used as a model contaminant to investigate the degradation kinetics using the microcomposites in aqueous suspensions. Kinetics of the photodegradation were evaluated by monitoring the changes in methyl orange concentration using UV-Vis spectroscopy. The photocatalytic behavior of functional microcomposites containing 65 wt% titania was studied and the influence of the solution pH as well as the total titania concentration in solution was explored. The results indicated that pH of the solution changes the surface interactions between the poly(acrylic acid), titania, and methyl orange and this interplay determined the overall degradation kinetics of the chemical contaminants. Nearly identical reaction rate constants were observed in acidic solutions for the microcomposites when compared to freely suspended titania. The latter showed higher rate constants than the microcomposites at a neutral pH. Release of the titania from the microcomposites was observed under basic conditions. Complete degradation of the microcomposites was observed after prolonged (7-13 h) UV irradiation. However, the microcomposites were easily regenerated by addition of microgels and no loss of photocatalytic activity was observed.

  17. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    The synthesis of polymer nanocomposites is an integral aspect of polymer nanotechnology. By inserting the nano- metric inorganic compounds, the properties of polymers improve and hence this has a lot of applications depending upon the inorganic material present in the polymers. Sol- vent casting is one of the easiest ...

  18. The Reinforcement Effect of Nano-Zirconia on the Transverse Strength of Repaired Acrylic Denture Base

    Directory of Open Access Journals (Sweden)

    Mohammed Gad

    2016-01-01

    Full Text Available Objective. The aim of this study was to evaluate the effect of incorporation of glass fiber, zirconia, and nano-zirconia on the transverse strength of repaired denture base. Materials and Methods. Eighty specimens of heat polymerized acrylic resin were prepared and randomly divided into eight groups (n=10: one intact group (control and seven repaired groups. One group was repaired with autopolymerized resin while the other six groups were repaired using autopolymerized resin reinforced with 2 wt% or 5 wt% glass fiber, zirconia, or nano-zirconia particles. A three-point bending test was used to measure the transverse strength. The results were analyzed using SPSS and repeated measure ANOVA and post hoc least significance (LSD test (P≤0.05. Results. Among repaired groups it was found that autopolymerized resin reinforced with 2 or 5 wt% nano-zirconia showed the highest transverse strength (P≤0.05. Repairs with autopolymerized acrylic resin reinforced with 5 wt% zirconia showed the lowest transverse strength value. There was no significant difference between the groups repaired with repair resin without reinforcement, 2 wt% zirconia, and glass fiber reinforced resin. Conclusion. Reinforcing of repair material with nano-zirconia may significantly improve the transverse strength of some fractured denture base polymers.

  19. Preparation of Caco-2 cell sheets using plasma polymerised acrylic acid as a weak boundary layer.

    Science.gov (United States)

    Majani, Ruby; Zelzer, Mischa; Gadegaard, Nikolaj; Rose, Felicity R; Alexander, Morgan R

    2010-09-01

    The use of cell sheets for tissue engineering applications has considerable advantages over single cell seeding techniques. So far, only thermoresponsive surfaces have been used to manufacture cell sheets without chemically disrupting the cell-surface interactions. Here, we present a new and facile technique to prepare sheets of epithelial cells using plasma polymerised acrylic acid films. The cell sheets are harvested by gentle agitation of the media without the need of any additional external stimulus. We demonstrate that the plasma polymer deposition conditions affect the viability and metabolic activity of the cells in the sheet and relate these effects to the different surface properties of the plasma polymerised acrylic acid films. Based on surface analysis data, a first attempt is made to explain the mechanism behind the cell sheet formation. The advantage of the epithelial cell sheets generated here over single cell suspensions to seed a PLGA scaffold is presented. The scaffold itself, prepared using a mould fabricated via photolithography, exhibits a unique architecture that mimics closely the dimensions of the native tissue (mouse intestine). Copyright 2010 Elsevier Ltd. All rights reserved.

  20. Synthesis and Pharmacological Evaluation of Acrylate-Based Gastrosparing NSAID Prodrugs.

    Science.gov (United States)

    Rasheed, Arun; Yalavarthi, Prasanna Raju; Cheramparambil, Haseena; Peesa, Jaya Preethi; Abdul Khareem, Azeem

    2017-04-01

    Dexibuprofen and aceclofenac are well-known NSAID molecules, their oral use leads to gastrointestinal (GI) toxicity. To circumvent that GI toxicity, the prodrug approach is a better alternative. Hence, this research was undertaken to synthesize prodrugs of dexibuprofen and aceclofenac using acrylic polymers with degradable ester bonds. Dexibuprofen was linked to 2-hydroxypropyl methacrylate by an activated ester technique. The resulting material was copolymerized with 2-hydroxyethyl methacrylate and methyl methacrylate (in 1:3 mole ratios) by the free radical polymerization method, utilizing azoisobutyronitrile at 65-70°C. Similarly aceclofenac was also processed. The resulting prodrugs were characterized by IR, NMR, and elemental analysis. The synthesized prodrugs possess optimal physicochemical characteristics such as the intended molecular weight, lipophilicity, partition coefficient, and protein binding. The drug release on hydrolysis was studied in various fluids such as SGF (pH 1.2), SIF (pH 7.4), and SCF (pH 6.8), to establish the drug release kinetics. Pharmacological evaluation exhibited anti-inflammatory activity with remarkable reduction in ulcerogenicity compared to the parent drug. Under the conditions used, the prodrugs showed no antigenicity in Wistar rats. Thus, it was concluded that acrylic-based prodrugs were efficient in drug localization in the stomach, without gastric problems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Isabelle Vroman

    2009-04-01

    Full Text Available Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources or from biological resources (renewable resources. In general natural polymers offer fewer advantages than synthetic polymers. The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their synthesis and applications.

  2. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  3. A facile one-pot synthesis of acrylated hyaluronic acid.

    Science.gov (United States)

    A, Sigen; Xu, Qian; McMichael, Peter; Gao, Yongsheng; Li, Xiaolin; Wang, Xi; Greiser, Udo; Zhou, Dezhong; Wang, Wenxin

    2018-01-25

    The synthesis of acrylated hyaluronic acid (HA-A) normally requires 2 to 3 steps of modification, needs laborious purification and also increases the risks of HA degradation. Here, we report that the conjugation of acrylate groups to hyaluronic acid can be successfully achieved via a new facile one-pot approach. Two types of new HA-A hydrogels (via chemical or UV crosslinking) were developed and applied for 3D cell encapsulation.

  4. Artificial saliva effect on toxic substances release from acrylic resins

    OpenAIRE

    Kostić Milena; Krunić Nebojša; Najman Stevo; Nikolić Ljubiša; Nikolić Vesna; Rajković Jelena; Petrović Milica; Igić Marko; Ignjatović Aleksandra

    2015-01-01

    Background/Aim. Acrylic-based resins are intensively used in dentistry practice as restorative or denture-base materials. The purpose of this study was to analyze the surface structure of denture base resins and the amount of released potentially toxic substances (PTS) immediately upon polymerization and incubation in different types of artificial saliva. Methods. Storage of acrylic samples in two models of artificial saliva were performed in a water bath a...

  5. Synthesis and Reactivity of Aluminized Fluorinated Acrylic (AIFA) Nanocomposites (Postprint)

    Science.gov (United States)

    2012-06-18

    REACTIVITY OF ALUMINIZED FLUORINATED ACRYLIC (ALFA) NANOCOMPOSITES (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...throughout the energetic materials community due to their strong reactivity with aluminum powders . Herein, we report the synthesis of a novel...These materials, which we have termed aluminized fluorinated acrylic (AlFA) composites, have been prepared with particle contents ranging from 10% to

  6. Poly(meth)acrylates obtained by cascade reaction.

    Science.gov (United States)

    Popescu, Dragos; Keul, Helmut; Moeller, Martin

    2011-04-04

    Preparation, purification, and stabilization of functional (meth)acrylates with a high dipole moment are complex, laborious, and expensive processes. In order to avoid purification and stabilization of the highly reactive functional monomers, a concept of cascade reactions was developed comprising enzymatic monomer synthesis and radical polymerization. Transacylation of methyl acrylate (MA) and methyl methacrylate (MMA) with different functional alcohols, diols, and triols (1,2,6-hexanetriol and glycerol) in the presence of Novozyme 435 led to functional (meth)acrylates. After the removal of the enzyme by means of filtration, removal of excess (meth)acrylate and/or addition of a new monomer, e.g., 2-hydroxyethyl (meth)acrylate the (co)polymerization via free radical (FRP) or nitroxide mediated radical polymerization (NMP) resulted in poly[(meth)acrylate]s with predefined functionalities. Hydrophilic, hydrophobic as well as ionic repeating units were assembled within the copolymer. The transacylation of MA and MMA with diols and triols carried out under mild conditions is an easy and rapid process and is suitable for the preparation of sensitive monomers. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Chemical modification of magnetite nanoparticles and preparation of acrylic-base magnetic nanocomposite particles via miniemulsion polymerization

    Science.gov (United States)

    Mahdieh, Athar; Mahdavian, Ali Reza; Salehi-Mobarakeh, Hamid

    2017-03-01

    Nowadays, magnetic nanocomposite particles have attracted many interests because of their versatile applications. A new method for chemical modification of Fe3O4 nanoparticles with polymerizable groups is presented here. After synthesis of Fe3O4 nanoparticles by co-precipitation method, they were modified sequentially with 3-aminopropyl triethoxysilane (APTES), acryloyl chloride (AC) and benzoyl chloride (BC) and all were characterized by FTIR, XRD, SEM and TGA analyses. Then the modified magnetite nanoparticles with unsaturated acrylic groups were copolymerized with methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA) through miniemulsion polymerization. Although several reports exist on preparation of magnetite-base polymer particles, but the efficiency of magnetite encapsulationwith reasonable content and obtaining final stable latexes with limited aggregation ofFe3O4 are still important issues. These were considered here by controlling reaction parameters. Hence, a seriesofmagneticnanocomposites latex particlescontaining different amounts of Fe3O4 nanoparticles (0-10 wt%) were prepared with core-shell morphology and diameter below 200 nm and were characterized by FT-IR, DSC and TGA analyses. Their morphology and size distribution were studied by SEM, TEM and DLS analyses too. Magnetic properties of all products were also measuredby VSM analysis and the results revealed almost superparamagnetic properties for the obtained nanocomposite particles.

  8. Emulsion Polymerization of Etyl Acrylate: The Effect of Surfactant, Initiator Concentration and PolymerizationTechnique on Particle Size Distribution

    Directory of Open Access Journals (Sweden)

    Nitri Arinda

    2009-04-01

    Full Text Available Emulsion polymerization was conducted using ethyl acrylate monomer. Theeffect of sodium lauryl sulfate concentration, ammonium persulfate concentration, the various of polymerizationtechniques and feeding time to the conversion, particle size and its distribution were observed. The purpose of thisresearch is to obtain the optimum condition of ethyl acrylate homopolymer with particle size around 100 nm, to get theparticle size distribution monodisperse and to get solid content value of the experiment closed to its theoretical value.The optimum condition then could be applied in shell polymerization of core-shell polymers. The results of the researchshowed that semicontinuous technique obtained optimum sodium lauryl sulfate concentration at 20 CMC (criticalmicelle concentration and ammonium persulfate concentration is 3%. By using batch technique that the biggestparticle size is 123 nm with conversion 95.8% and monodisperse. The shorter of feeding time the more monomer ofethyl acrylate being polymerized, it is showed by the higher conversion up to 94.4% and the bigger particle size is107.9 nm.

  9. SYNTHESIS AND CHARACTERIZATION OF ACRYLATED PARKIA ...

    African Journals Online (AJOL)

    a

    -Ekiti, Ekiti state, Nigeria ... tree of 30-70 ft high. It bears fruits and the matured and ripe pods have edible pulp [3]. The seeds are processed into a local product (Iru in Yoruba) used as soup ingredient. ... preformed acid containing polymer.

  10. Development and Evaluation of Ketoprofen Acrylic Transdermal ...

    African Journals Online (AJOL)

    Results: DSC thermograms demonstrate that the drug was dispersed molecularly in the polymer in all the formulations. Increase in PSA content increased the W/A ratio and adhesiveness of KTPs. Ketoprofen release from the transdermal patches followed the Higuchi diffusion model. Ketoprofen flux increased with increase ...

  11. Advances in acrylic-alkyd hybrid synthesis and characterization

    Science.gov (United States)

    Dziczkowski, Jamie

    2008-10-01

    In situ graft acrylic-alkyd hybrid resins were formed by polymerizing acrylic and acrylic-mixed monomers in the presence of alkyds by introduction of a free radical initiator to promote graft formation. Two-dimensional NMR, specifically gradient heteronuclear multiple quantum coherence (gHMQC), was used to clarify specific graft sites of the hybrid materials. Both individual and mixed-monomer systems were produced to determine any individual monomer preferences and to model current acrylic-alkyd systems. Different classes of initiators were used to determine any initiator effects on graft location. The 2D-NMR results confirm grafting at doubly allylic hydrogens located on the fatty acid chains and the polyol segment of the alkyd backbone. The gHMQC spectra show no evidence of grafting across double bonds on either pendant fatty acid groups or THPA unsaturation sites for any of the monomer or mixed monomer systems. It was also determined that choice of initiator has no effect on graft location. In addition, a design of experiments using response surface methodology was utilized to obtain a better understanding of this commercially available class of materials and relate both the chemical and physical properties to one another. A Box-Behnkin design was used, varying the oil length of the alkyd phase, the degree of unsaturation in the polyester backbone, and acrylic to alkyd ratio. Acrylic-alkyd hybrid resins were reduced with an amine/water mixture. Hydrolytic stability was tested and viscoelastic properties were obtained to determine crosslink density. Cured films were prepared and basic coatings properties were evaluated. It was found that the oil length of the alkyd is the most dominant factor for final coatings properties of the resins. Acrylic to alkyd ratio mainly influences the resin properties such as acid number, average molecular weight, and hydrolytic stability. The degree of unsaturation in the alkyd backbone has minimal effects on resin and film

  12. Linear Viscoelasticity of Spherical SiO 2 Nanoparticle-Tethered Poly(butyl acrylate) Hybrids

    KAUST Repository

    Goel, Vivek

    2010-12-01

    The melt state linear viscoelastic properties of spherical silica nanoparticles with grafted poly(n-butyl acrylate) chains of varying molecular weight were probed using linear small amplitude dynamic oscillatory measurements and complementary linear stress relaxation measurements. While the pure silica-tethered-polymer hybrids with no added homopolymer exhibit solid-like response, addition of matched molecular weight free matrix homopolymer chains to this hybrid, at low concentrations of added homopolymer, maintains the solid-like response with a lowered modulus that can be factored into a silica concentration dependence and a molecular weight dependence. While the silica concentration dependence of the modulus is strong, the dependence on molecular weight is weak. On the other hand, increasing the amount of added homopolymer changes the viscoelastic response to that of a liquid with a relaxation time that scales exponentially with hybrid concentration. © 2010 American Chemical Society.

  13. Synthesis and characterization of functional acrylic copolymers via RAFT mini-emulsion polymerization

    Science.gov (United States)

    Yılmaz, Onur; Özkan, ćiǧdem Kılıçarislan; Yılmaz, Catalina N.; Yorgancıoǧlu, Ali; Özgünay, Hasan; Karavana, Hüseyin Ata

    2017-12-01

    Copolymers bearing reactive functional groups with controlled molecular weights are of importance since they can be used in many fields such as composites, coatings, membranes, catalysis, biology, optoelectronics, pharmaceuticals, etc. In the present study low molecular weight copolymers based on butyl acrylate (BA) and methyl methacrylate (MMA) in combination with reactive functional monomers of vinyl trietoxysilane (VTES), 3-trimetoxysilylpropyl methacrylate (TMSPMA) and glycidyl methacrylate (GMA) were synthesized via RAFT mini-emulsion technique using 2-cyano 2-propyldodecyldithiocarbonate as CTA agent. The results showed that the average molecular weights of copolymers were close to the theoretical values. On the other hand, PDI values were found to be higher than conventional RAFT polymers. The particle sizes of the latexes were small with very homogenous distributions and good stability. FTIR, H-NMR and TGA results verified the success of copolymer syntheses.

  14. Bonding durability between acrylic resin adhesives and titanium with surface preparations.

    Science.gov (United States)

    Yanagida, Hiroaki; Minesaki, Yoshito; Matsumura, Kousuke; Tanoue, Naomi; Muraguchi, Koichi; Minami, Hiroyuki

    2017-01-31

    The purpose of the present study was to evaluate the efficacy of pretreatment on the bonding durability between titanium casting and two acrylic adhesives. Cast titanium disk specimens treated with four polymer-metal bonding systems as follow: 1) air-abraded with 50-70 μm alumina, 2) 1)+Alloy Primer, 3) 1)+M.L. Primer and 4) tribochemical silica/silane coating system (Rocatec System). The specimens were bonded with M bond or Super-bond C&B adhesive. The shear bond strengths were determined before and after thermocycling (20,000 cycles). The surface characteristics after polishing, and for the 1) and 4) preparations were determined. The bond strengths for all combinations significantly decreased after thermocycling. The combination of Super-bond C&B adhesive and 2) led to significantly higher bond strength than the other preparations after thermocycling. The maximum height of the profile parameters for the polishing group was lower than other preparations.

  15. Surfactant and counter-ion distribution in styrene-butyl acrylate-acrylic acid dry latex submonolayers

    OpenAIRE

    Keslarek Amauri José; Leite Carlos Alberto P; Galembeck Fernando

    2004-01-01

    Styrene-butyl acrylate-acrylic acid latex submonolayers prepared using a non-reactive phosphate surfactant together with a reactive sulfonate surfactant were examined in a transmission microscope using electron energy loss spectroscopy imaging (ESI-TEM). Phosphorus is nearly absent from the particles core but it is detected in a thick shell and in unusual, strongly scattering structures with a low carbon content, and largely made out of inorganic phosphate. P is also dispersed outside the par...

  16. Organocatalytic conjugate-addition polymerization of linear and cyclic acrylic monomers by N-heterocyclic carbenes: mechanisms of chain initiation, propagation, and termination.

    Science.gov (United States)

    Zhang, Yuetao; Schmitt, Meghan; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y-X

    2013-11-27

    This contribution presents a full account of experimental and theoretical/computational investigations into the mechanisms of chain initiation, propagation, and termination of the recently discovered N-heterocyclic carbene (NHC)-mediated organocatalytic conjugate-addition polymerization of acrylic monomers. The current study specifically focuses on three commonly used NHCs of vastly different nucleophilicity, 1,3-di-tert-butylimidazolin-2-ylidene (I(t)Bu), 1,3-dimesitylimidazolin-2-ylidene (IMes), and 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene (TPT), and two representative acrylic monomers, the linear methyl methacrylate (MMA) and its cyclic analog, biomass-derived renewable γ-methyl-α-methylene-γ-butyrolactone (MMBL). For MMA, there exhibits an exquisite selectivity of the NHC structure for the three types of reactions it promotes: enamine formation (single-monomer addition) by IMes, dimerization (tail-to-tail) by TPT, and polymerization by I(t)Bu. For MMBL, all three NHCs promote no dimerization but polymerization, with the polymerization activity being highly sensitive to the NHC structure and the solvent polarity. Thus, I(t)Bu is the most active catalyst of the series and converts quantitatively 1000-3000 equiv of MMBL in 1 min or 10,000 equiv in 5 min at room temperature to MMBL-based bioplastics with a narrow range of molecular weights of M(n) = 70-85 kg/mol, regardless of the [MMBL]/[I(t)Bu] ratio employed. The I(t)Bu-catalyzed MMBL polymerization reaches an exceptionally high turnover frequency up to 122 s(-1) and a high initiator efficiency value up to 1600%. Unique chain-termination mechanisms have been revealed, accounting for the production of relative high-molecular-weight linear polymers and the catalytic nature of this NHC-mediated conjugate-addition polymerization. Computational studies have provided mechanistic insights into reactivity and selectivity between two competing pathways for each NHC-monomer zwitterionic adduct, namely

  17. Organocatalytic conjugate-addition polymerization of linear and cyclic acrylic monomers by N-heterocyclic carbenes: Mechanisms of chain initiation, propagation, and termination

    KAUST Repository

    Zhang, Yuetao

    2013-11-27

    This contribution presents a full account of experimental and theoretical/computational investigations into the mechanisms of chain initiation, propagation, and termination of the recently discovered N-heterocyclic carbene (NHC)-mediated organocatalytic conjugate-addition polymerization of acrylic monomers. The current study specifically focuses on three commonly used NHCs of vastly different nucleophilicity, 1,3-di-tert-butylimidazolin-2-ylidene (ItBu), 1,3- dimesitylimidazolin-2-ylidene (IMes), and 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4- triazol-5-ylidene (TPT), and two representative acrylic monomers, the linear methyl methacrylate (MMA) and its cyclic analog, biomass-derived renewable γ-methyl-α-methylene-γ-butyrolactone (MMBL). For MMA, there exhibits an exquisite selectivity of the NHC structure for the three types of reactions it promotes: enamine formation (single-monomer addition) by IMes, dimerization (tail-to-tail) by TPT, and polymerization by ItBu. For MMBL, all three NHCs promote no dimerization but polymerization, with the polymerization activity being highly sensitive to the NHC structure and the solvent polarity. Thus, ItBu is the most active catalyst of the series and converts quantitatively 1000-3000 equiv of MMBL in 1 min or 10 000 equiv in 5 min at room temperature to MMBL-based bioplastics with a narrow range of molecular weights of Mn = 70-85 kg/mol, regardless of the [MMBL]/[ItBu] ratio employed. The ItBu-catalyzed MMBL polymerization reaches an exceptionally high turnover frequency up to 122 s -1 and a high initiator efficiency value up to 1600%. Unique chain-termination mechanisms have been revealed, accounting for the production of relative high-molecular-weight linear polymers and the catalytic nature of this NHC-mediated conjugate-addition polymerization. Computational studies have provided mechanistic insights into reactivity and selectivity between two competing pathways for each NHC-monomer zwitterionic adduct, namely enamine

  18. Prevention of thermally induced aggregation of IgG antibodies by noncovalent interaction with poly(acrylate) derivatives.

    Science.gov (United States)

    Martin, Nicolas; Ma, Dewang; Herbet, Amaury; Boquet, Didier; Winnik, Françoise M; Tribet, Christophe

    2014-08-11

    Prevention of thermal aggregation of antibodies in aqueous solutions was achieved by noncovalent association with hydrophobically modified poly(acrylate) copolymers. Using a polyclonal immunoglobin G (IgG) as a model system for antibodies, we have studied the mechanisms by which this multidomain protein interacts with polyanions when incubated at physiological pH and at temperatures below and above the protein unfolding/denaturation temperature, in salt-free solutions and in 0.1 M NaCl solutions. The polyanions selected were sodium poly(acrylates), random copolymers of sodium acrylate and N-n-octadecylacrylamide (3 mol %), and a random copolymer of sodium acrylate, N-n-octylacrylamide (25 mol %), and N-isopropylacrylamide (40 mol %). They were derived from two poly(acrylic acid) parent chains of Mw 5000 and 150000 g·mol(-1). The IgG/polyanion interactions were monitored by static and dynamic light scattering, fluorescence correlation spectroscopy, capillary zone electrophoresis, and high sensitivity differential scanning calorimetry. In salt-free solutions, the hydrophilic PAA chains form complexes with IgG upon thermal unfolding of the protein (1:1 w/w IgG/PAA), but they do not interact with native IgG. The complexes exhibit a remarkable protective effect against IgG aggregation and maintain low aggregation numbers (average degree of oligomerization <12 at a temperature up to 85 °C). These interactions are screened in 0.1 M NaCl and, consequently, PAAs lose their protective effect. Amphiphilic PAA derivatives (1:1 w/w IgG/polymer) are able to prevent thermal aggregation (preserving IgG monomers) or retard aggregation of IgG (formation of oligomers and slow growth), revealing the importance of both hydrophobic interactions and modulation of the Coulomb interactions with or without NaCl present. This study leads the way toward the design of new formulations of therapeutic proteins using noncovalent 1:1 polymer/protein association that are transient and require a

  19. Coating materials and solvents. 2. Acrylic acid, acrylate, and MMA; Toryo yozai. 2. Akurirusan oyobi akurirusan esuteru MMA

    Energy Technology Data Exchange (ETDEWEB)

    Akazawa, Y. [Nippon Shokubai Co. Ltd., Osaka (Japan)

    1997-09-01

    This paper describes the production process, its scale, physical properties and usage of acrylic acid, acrylate for general use, and MMA (methyl methacrylate). The propylene oxidation process is only one process for the industrial production of acrylic acid and acrylate due to its economical predominance. Annual production of acrylic acid in the world has reached to about 2.2 million tons. Relatively high growth rate is forecasted also in the future. In Japan, the acrylate is used for paints, adhesive materials, and fibers. The industrial production process of MMA includes ACH (acetone cyanhydrin) process, new ACH process, isobutylene process, MAN (methacrylonitrile) process, and ethylene carbonylation process. Demand and supply of MMA are characterized especially by the high proportion of export from Japan to the Asian region. Methacrylic resins are used for various materials, such as tail lamp lenses and meter panels of automobiles, and laser disks, CD-ROM and MD pick-ups in the field of electronic industry. Consumption of these resins is steadily extended. 16 refs., 6 figs., 7 tabs.

  20. Design and characterization of diclofenac diethylamine transdermal patch using silicone and acrylic adhesives combination

    Directory of Open Access Journals (Sweden)

    Panchaxari Dandigi M

    2013-01-01

    Full Text Available Abstract Background and purpose of the study The objective of the study was to develop and characterize Diclofenac Diethylamine (DDEA transdermal patch using Silicone and acrylic adhesives combination. Methods Modified solvent evaporation method was employed for casting of film over Fluoropolymer coated polyester release liner. Initial studies included solubilization of drug in the polymers using solubilizers. The formulations with combination of adhesives were attempted to combine the desirable features of both the adhesives. The effect of the permeation enhancers on the drug permeation were studied using pig ear skin. All the optimized patches were subjected to adhesion, dissolution and stability studies. A 7-day skin irritancy test on albino rabbits and an in vivo anti-inflammatory study on wistar rats by carrageenan induced paw edema method were also performed. Results The results indicated the high percent drug permeation (% CDP-23.582 and low solubility nature (1% of Silicone adhesive and high solubility (20% and low% CDP (10.72% of acrylic adhesive. The combination of adhesives showed desirable characteristics for DDEA permeation with adequate % CDP and sufficient solubility. Release profiles were found to be dependent on proportion of polymer and type of permeation enhancer. The anti-inflammatory study revealed the sustaining effect and high percentage inhibition of edema of C4/OLA (99.68%. The acute skin irritancy studies advocated the non-irritant nature of the adhesives used. Conclusion It was concluded that an ideal of combination of adhesives would serve as the best choice, for fabrication of DDEA patches, for sustained effect of DDEA with better enhancement in permeation characteristics and robustness.