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Sample records for stability waterborne polyurethanes

  1. Stability of biodegradable waterborne polyurethane films in buffered saline solutions.

    Science.gov (United States)

    Lin, Ying Yi; Hung, Kun-Che; Hsu, Shan-Hui

    2015-09-21

    The stability of polyurethane (PU) is of critical importance for applications such as in coating industry or as biomaterials. To eliminate the environmental concerns on the synthesis of PU which involves the use of organic solvents, the aqueous-based or waterborne PU (WBPU) has been developed. WBPU, however, may be unstable in an electrolyte-rich environment. In this study, the authors reported the stability of biodegradable WBPU in the buffered saline solutions evaluated by atomic force microscopy (AFM). Various biodegradable WBPU films were prepared by spin coating on coverslip glass, with a thickness of ∼300 nm. The surface AFM images of poly(ε-caprolactone) (PCL) diol-based WBPU revealed nanoglobular structure. The same feature was observed when 20% molar of the PCL diol soft segment was replaced by polyethylene butylenes adipate diol. After hydration in buffered saline solutions for 24 h, the surface domains generally increased in sizes and became irregular in shape. On the other hand, when the soft segment was replaced by 20% poly(l-lactide) diol, a meshlike surface structure was demonstrated by AFM. When the latter WBPU was hydrated, the surface domains appeared to be disconnected. Results from the attenuated total reflectance infrared spectroscopy and x-ray photoelectron spectroscopy indicated that the surface chemistry of WBPU films was altered after hydration. These changes were probably associated with the neutralization of carboxylate by ions in the saline solutions, resulting in the rearrangements of soft and hard segments and causing instability of the WBPU.

  2. Preparation and properties of high storage stability polyester polyol dispersion for two-component waterborne polyurethane coating

    Science.gov (United States)

    Hao, H.; Hu, J. Q.; Wang, F.; Tu, W. P.

    2017-01-01

    A new type of polyester polyol dispersion with good storage stability was prepared based on a hydrophilic monomer 5-sodium sulfodimethyl isophthalate (5-SIPM), and frequently-used monomers such as neopentyl glycol (NPG), dimethyl terephthalate (DMT), dimethyl phthalate (DMP) and trimethylolpropane (TMP) by the transpolycondensation and polycondensation method. The polyester polyol dispersion was characterized by FTIR and GPC. The proper content of these monomers were determined by the performance of polyester dispersion: the content of TMP was 15wt%, the content of NPG was 7.5wt% and the hydrophilic monomer 5-SIPM content was 5wt%. Two-component waterborne polyurethane (2K-WPU) coatings were prepared by Bayhydur® XP2487/1 and polyester polyol dispersions, which were stored before and after at 40 ° for 6 weeks, the prepared films have no differences in drying time, adhesion, pencil hardness, gloss and chemical resistance, the result also reveals that the polyester polyol dispersion have excellent storage stability resistance.

  3. Nanoclay Dispersion and its Effect on Properties of Waterborne Polyurethanes

    Directory of Open Access Journals (Sweden)

    H. Honarkar

    2014-01-01

    Full Text Available In recent years, waterborne polyurethanes as in coatings and adhesives formulations have attracted considerable attention because they are non-toxic, non-flammable and friendly to environment. Besides environmental management, the flexibility, low temperature property, high tensile strength, good adhesion and improved rheological property are specific properties of waterborne polyurethanes. Also low production cost of water borne polyurethanes over solvent-borne polyurethanes is also a reason for their applications. However, these materials have some defects such as weak water resistance and low adhesion in the moisture environment due to sensitivity of their hydrophilic ionic bonds, ether groups, urethane and ester groups to hydrolysis which need to be improved. Also, low heat resistance of these materials is due to a relatively low crystalline melting point or glass transition temperature of hard segments. One of the ways to solve this problem and improve its properties for different applications is the addition of inorganic fillers especially nano-sized layered silicates within polyurethane matrix. In this way water resistance, heat resistance, mechanical properties and modulus increase simultaneously. In this research, waterborne polyurethane nanocomposites with PTMG polyol, IPDI, DMPA (internal emulsifier, TEA (neutralizer and 1, 3 and 5weight % of Cloisite 30B as reinforcement were synthesized and characterized. Polarity of the samples was investigated by contact angle test and dispersion of nano particles in the samples was characterized by X-Ray and TEM, Thermal properties and dynamic mechanical properties were measured by TGA and DMTA, respectively. The results showed that incorporation of clay into polyurethanes did reduce water absorption and increased heat resistance, modulus, particle size and contact angle.In recent years, waterborne polyurethanes including coatings and adhesives have attracted considerable attention because they

  4. Synthesis, characterization and fluorescence performance of a waterborne polyurethane-based polymeric dye

    Energy Technology Data Exchange (ETDEWEB)

    Xianhai, Hu, E-mail: hxyh@aiai.edu.cn [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); School of Materials and Chemical Engineering, Building Energy Efficiency Research Institute, Anhui University of Architecture, Hefei 230022 (China); Zhang, Xingyuan, E-mail: zxym@ustc.edu.cn [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Liu, Jin [School of Materials and Chemical Engineering, Building Energy Efficiency Research Institute, Anhui University of Architecture, Hefei 230022 (China); Dai, Jiabing [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026 (China)

    2013-10-15

    A novel anionic waterborne polyurethane-based fluorescent dye WPU-DV26 was synthesized by incorporating the molecular structure of disperse violet 26 (DV26) into the polyurethane chain. The structure of WPU-DV26 was confirmed by means of Fourier transform infrared spectroscopy and UV–vis absorption analysis. Comparing to the UV–vis spectrum of DV26, WPU-DV26 showed a hypsochromic shift from the absorption maxima of 518, 558, 609 nm to 510, 548, 586 nm, respectively. WPU-DV26 can form stable latex in water. The number average molecular weight and its distribution index, and average latex particle size for WPU-DV26 were determined to be 2.33×10{sup 4}, 1.36 and 80 nm, respectively. The improved thermal stability of WPU-DV26 can be attributed to the embedded anthraquinone unit of DV26. It was found that both the intensity and stability of the fluorescence of WPU-DV26 latex were improved significantly compared with those of DV26. -- Highlights: ► A waterborne polyurethane-based polymeric dye was synthesized. ► The fluorescence intensity of WPU-DV26 emulsion was enhanced greatly compared with that of DV26. ► The fluorescence stability of WPU-DV26 emulsion was fine not only for long term storage but also for fluorescence quencher.

  5. Design of self-dispersible charged-polymer building blocks for waterborne polyurethane dispersions

    NARCIS (Netherlands)

    Jiménez-Pardo, I.; Sun, P.; van Benthem, R.A.T.M.; Esteves, A.C.C.

    2018-01-01

    Waterborne polyurethane dispersions (PUDs) currently have a wide spectrum of applications as coating resins for biomedical products, food packaging, cosmetics and traditional coatings. At present, PUDs are commonly prepared by the “prepolymer extension” method in which isocyanate terminated

  6. Autonomic healable waterborne organic-inorganic polyurethane hybrids based on aromatic disulfide moieties

    Directory of Open Access Journals (Sweden)

    R. H. Aguirresarobe

    2017-04-01

    Full Text Available Aromatic disulfide dynamic structures were incorporated as chain extenders in waterborne organic-inorganic polyurethane hybrids in order to provide autonomic healable characteristics. The synthesis was carried out following the acetone process methodology and the influence of the introduction of the healing agents in the polymer dispersion stability was analyzed. After the crosslinking process at room temperature, organic-inorganic hybrid films, which presented autonomic healing characteristics, were obtained. These features were evaluated by means of stress-strain tests and the films showed repetitive healing abilities. Thus, the optimum healing time at room temperature (25 °C as well as the influence of different parameters in the healing efficiency, such the aromatic disulfide concentration or the physical properties of the polymer matrix were analyzed.

  7. Synthesis of waterborne, branched, functional poly(urethane)s and theire applications

    OpenAIRE

    Ongun, Nihan

    2014-01-01

    Polyurethanes are an important class of polymers that have wide application in a number of different industrial sectors. Their versatile chemistry enables researchers to design novel materials ranging from liquid, soft and rubbery solids to rigid thermoplastic and thermoset polymer for elastomeric materials, coating and adhesive. The present study focuses on synthesizing waterborne, branched and chemically functional polyurethanes with unique architectures via novel methodologies for coating ...

  8. A novel silanized CoFe{sub 2}O{sub 4}/fluorinated waterborne polyurethane pressure sensitive adhesive

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Heqing, E-mail: fuhq@scut.edu.cn; Wang, Yin; Chen, Weifeng; Zhou, Wei; Xiao, Jing

    2015-10-01

    Highlights: • The hydrophobicity, thermal stability, dynamic mechanical properties, as well as adhesive properties of silanized. • CoFe{sub 2}O{sub 4}/fluorinated waterborne polyurethane (SC/FWPU) were improved with the incorporation of silanized CoFe{sub 2}O{sub 4} into FWPU. • The higher the spreading-penetration parameter is, the faster the contact angle reaches equilibrium, and the faster the SC/FWPU pressure sensitive adhesive penetrates and spreads. - Abstract: A novel silanized CoFe{sub 2}O{sub 4}/fluorinated waterborne polyurethane (SC/FWPU) pressure sensitive adhesive was synthesized and characterized by atomic force microscopy (AFM), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and contact angle tester. The adhesive properties were measured in a test machine. Experimental results showed that the hydrophobicity, thermal stability, dynamic mechanical properties, as well as adhesive properties of SC/FWPU were improved with the incorporation of SC into FWPU. The dynamic hydrophobicity can be well described by the wetting kinetic model. The spreading-penetration parameter increased with an increase in SC content. The higher the spreading-penetration parameter is, the faster the contact angle reaches equilibrium, and the faster the SC/FWPU pressure sensitive adhesive penetrates and spreads.

  9. Synthesis and characterization of waterborne polyurethane acrylate copolymers

    International Nuclear Information System (INIS)

    Sultan, Misbah; Bhatti, Haq Nawaz; Zuber, Mohammad; Barikani, Mehdi

    2013-01-01

    Polyurethane acrylate copolymers were synthesized by emulsion polymerization process. To reduce the environmental hazards, organic solvents were replaced by eco-friendly aqueous system. Concentration of polyurethane and acrylate monomer was varied to investigate the effect of chemical composition on performance properties of copolymers. FTIR spectroscopy was used as a key tool to record the chemical synthesis route. The synthesized copolymer emulsions were characterized by evaluating their particle size, viscosity, dry weight content, chemical and water resistance. Thermal decomposition was studied by thermogravimetric analysis. Scanning electron microscope was used to visualize the morphological structure of copolymers. The experimental results indicate better polyurethane acrylate compatibility till the ratio of 30/70. However, these copolymers exhibited synergistic effects between the two polymers and revealed a remarkable improvement in numerous coating properties

  10. Fully glutathione degradable waterborne polyurethane nanocarriers: Preparation, redox-sensitivity, and triggered intracellular drug release

    Energy Technology Data Exchange (ETDEWEB)

    Omrani, Ismail; Babanejad, Niloofar; Shendi, Hasan Kashef; Nabid, Mohammad Reza, E-mail: m-nabid@sbu.ac.ir

    2017-01-01

    Polyurethanes are important class of biomaterials that are extensively used in medical devices. In spite of their easy synthesis, polyurethanes that are fully degradable in response to the intracellular reducing environment are less explored for controlled drug delivery. Herein, a novel glutathione degradable waterborne polyurethane (WPU) nanocarrier for redox triggered intracellular delivery of a model lipophilic anticancer drug, doxorubicin (DOX) is reported. The WPU was prepared from polyaddition reaction of isophorone diisocyanate (IPDI) and a novel linear polyester polyol involving disulfide linkage, disulfide labeled chain extender, dimethylolpropionic acid (DMPA) using dibutyltin dilaurate (DBTDL) as a catalyst. The resulting polyurethane self-assembles into nanocarrier in water. The dynamic light scattering (DLS) measurements and scanning electron microscope (SEM) revealed fast swelling and disruption of nanocarriers under an intracellular reduction-mimicking environment. The in vitro release studies showed that DOX was released in a controlled and redox-dependent manner. MTT assays showed that DOX-loaded WPU had a high in vitro antitumor activity in both HDF noncancer cells and MCF- 7 cancer cells. In addition, it is found that the blank WPU nanocarriers are nontoxic to HDF and MCF-7 cells even at a high concentration of 2 mg/mL. Hence, nanocarriers based on disulfide labeled WPU have appeared as a new class of biocompatible and redox-degradable nanovehicle for efficient intracellular drug delivery. - Highlights: • A novel fully glutathione degradable waterborne polyurethane was developed. • The waterborne nanocarrier with disulfide bonds in both hard and soft segment were developed for redox-triggered intracellular delivery of DOX. • The polyester diol bearing disulfide bonds in the backbone was prepared by a polycondensation polymerization reaction.

  11. The Effect of Improved Crosslink Density on the Properties of Waterborne Polyurethanes Using Sol-Gel Process

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Ryul; Park, Jin Hwan [Pukyong National University, Busan (Korea, Republic of)

    2016-12-15

    Water-based systems are dominating the coating market because of worldwide VOCs regulations. Research is focusing especially on waterborne polyurethane (WPU) because of its unique mechanical and chemical properties. However, commercial WPU consists of linear thermoplastic polymers with polar groups on the main chain, which do not perform as well as solvent-borne PU in a two-pack system. In this study, APTES were used as a chain crosslink agent to overcome commercial WPU's limited performance. WPUs synthesized by using a sol-gel process were evaluated with FT-IR, particle analysis, TGA, tensile tests, pull-off tests, SEM, and EIS. The results showed that WPUs with added APTES had better thermal stability, mechanical properties, and water resistance than did WPUs without added APTES. Consequently, the sol-gel process increased the crosslink density of WPUs and modified the WPU's own properties.

  12. Hybrid thin films derived from UV-curable acrylate-modified waterborne polyurethane and monodispersed colloidal silica

    Directory of Open Access Journals (Sweden)

    C. H. Yang

    2012-01-01

    Full Text Available Hybrid thin films containing nano-sized inorganic domains were synthesized from UV-curable acrylate-modified waterborne polyurethane (WPU-AC and monodispersed colloidal silica with coupling agent. The coupling agent, 3-(trimethoxysilylpropyl methacrylate (MSMA, was bonded onto colloidal silica first, and then mixed with WPU-AC to form a precursor solution. This precursor was spin coated, dried and UV-cured to generate the hybrid films. The silica content in the hybrid thin films was varied from 0 to 30 wt%. Experimental results showed the aggregation of silica particles in the hybrid films. Thus, the silica domain in the hybrid films was varied from 30 to 50 nm by the different ratios of MSMAsilica to WPU-AC. The prepared hybrid films from the crosslinked WPU-AC/MSMA-silica showed much better thermal stability and mechanical properties than pure WPU-AC.

  13. Novel electrochromic devices based on composite films of poly(2,5-dimethoxyaniline)-waterborne polyurethane

    International Nuclear Information System (INIS)

    Yang, C.-H.; Chong, L.-W.; Huang, L.-M.; Lee, Y.-L.; Wen, T.-C.

    2005-01-01

    Waterborne polyurethane (WPU) was spin-coated on indium tin oxide (ITO) coated glass. Poly(2,5-dimethoxyaniline) (PDMA) was deposited using electrochemical polymerization as conducting composite film on the above WPU/ITO electrode and used as an electrode in an electrochromic device assembly. Tungsten oxide (WO 3 ) coated ITO glass was used as the other electrode with LiClO 4 doped gelled polyethylene oxide (PEO) as polymer electrolyte. The configuration of an electrochromic device was assembled: ITO/WPU-PDMA II LiClO 4 -PC-PEO (400,000) II WO 3 /ITO, where PC represents propylene carbonate. The characterization of the single electrodes, ITO/WPU-PDMA composite, ITO/WO 3 , and the device was performed by using cyclic voltammetry. The columbic efficiency (CE) of the ITO/WPU-PDMA composite and ITO/WO 3 electrodes were close to 100%. The optical contrast of the single electrodes and the device were determined by UV-vis spectroelectrochemical studies. A visible contrast in color upon switching the potential from -1.50 to +1.50 V was noticed for the device. The device was pale yellow at -1.5 V and dark green at +1.5 V. The CE of the device was 91%. Double potential chronamperomtry was used to determine the response time of coloring and bleaching processes. The bleaching process was found to be faster than coloring. The stability of the device was established by polarizing the device and recording the UV-vis spectrum in open circuit conditions. Bleaching state is more stable than coloring state

  14. Structure, properties and application of a novel low-glossed waterborne polyurethane

    International Nuclear Information System (INIS)

    Li, Jianjun; Zheng, Wen; Zeng, Wenbo; Zhang, Dongqiao; Peng, Xiaohong

    2014-01-01

    Waterborne polyurethane (WPU) with low gloss was prepared successfully and used as surface modifier to adjust the gloss of leather. The structure and morphology of the WPU films were characterized by Fourier transform infrared spectrometer (FTIR), Atomic force microscope (AFM) and Scanning electron microscope (SEM). Then the factors affecting the gloss, light transmittance and water absorption of WPU films including varieties and amount of chain extenders, n NCO /n OH molar ratio and 2-[(2-aminoethyl)amino]ethyl sulfonic acid sodium content.etc were studied. Results showed that the WPU film possessed a broad particle size distribution combined with a relatively large particle size. This kind of novel WPU would be widely used in polyvinyl chloride, polyurethane synthetic leather surface.

  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. The effect of polyether functional polydimethylsiloxane on surface and thermal properties of waterborne polyurethane

    Science.gov (United States)

    Zheng, Guikai; Lu, Ming; Rui, Xiaoping

    2017-03-01

    Waterborne polyurethanes (WPU) modified with polyether functional polydimethylsiloxane (PDMS) were synthesized by pre-polymerization method using isophorone diisocyanate (IPDI) and 1,4-butanediol (BDO) as hard segments and polybutylene adipate glycol (PBA) and polyether functional PDMS as soft segments. The effect of polyether functional PDMS on phase separation, thermal properties, surface properties including surface composition, morphology and wettability were investigated by FTIR, contact angle measurements, ARXPS, SEM-EDS, AFM, TG and DSC. The results showed that the compatibility between urethane hard segment and PDMS modified with polyether was good, and there was no distinct phase separation in both bulk and surface of WPU films. The degradation temperature and low temperature flexibility increased with increasing amounts of polyether functional PDMS. The enrichment of polyether functional PDMS with low surface energy on the surface imparted excellent hydrophobicity to WPU films.

  17. Waterborne polyurethane single-ion electrolyte from aliphatic diisocyanate and various molecular length of polyethylene glycol

    Directory of Open Access Journals (Sweden)

    2007-03-01

    Full Text Available The waterborne polyurethane (WPU dispersions from the reaction of cycloaliphatic diisocyanates [4,4’-methylenebis(cyclohexyl isocyanate (H12MDI and isophorone diisocyanate (IPDI] and polyethylene glycol (PEG with various molecular lengths were synthesized using our modified acetone process. Differetial scanning calorimeter (DSC and Fourier transform infrared spectroscopy (FTIR were utilized to characterize WPU films for the behavior of their crystallinity and H-bonding of WPU films. The Tg value of WPU increases with increasing the molecular length of PEG, whereas the Tm of WPU decreases with increasing PEG length. Alternating current (AC impedance experiments were performed to determine the ionic conductivities of WPU films. The WPU gel electrolytes exhibits an ionic conductivity as high as ~ 10-5 S/cm at room temperature.

  18. Preparation and Characterization of Coating Solution Based on Waterborne Polyurethane Dispersion containing Fluorine for Primer on Electro Galvanized Steel Sheet

    International Nuclear Information System (INIS)

    Jin, Chung Keun; Lim, Sung Hyung

    2015-01-01

    The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU

  19. Preparation and Characterization of Coating Solution Based on Waterborne Polyurethane Dispersion containing Fluorine for Primer on Electro Galvanized Steel Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Chung Keun; Lim, Sung Hyung [Buhmwoo Institute of Technology Research, Hwaseong (Korea, Republic of)

    2015-10-15

    The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU.

  20. Synthesis of waterborne polyurethane containing alkoxysilane side groups and the properties of the hybrid coating films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qi; Guo, Longhai [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Qiu, Teng, E-mail: qiuteng@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Xiao, Weidong; Du, Dianxing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Xiaoyu, E-mail: lixy@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)

    2016-07-30

    Highlights: • A diol with side-chain trimethoxysilane (DEA-Si) was synthesized using 3-(methacryloxypropyl)trimethoxysilane (MAPTS) and diethanolamine (DEA). • The crosslinking structure could in situ formed within the WPU matrix through sol-gel process. • The Si tends to shift to the polymer-air interface due to the flexible long alkyl-ester side chain. • The incorporation of DEA-Si enhanced mechanical and surface hydrophobic properties of WPU films. - Abstract: A series of waterborne polyurethane (WPU) containing alkoxysilane side groups were synthesized by using the dihydroxy functionalized alkoxysilane. The diol with trimethoxysilane groups at the side chains was synthesized via Michael addition between 3-(methacryloxypropyl)trimethoxysilane (MAPTS) and diethanolamine (DEA). The silane diol was applied as the chain extender for the NCO-endcapped prepolymer of isophorone diisocyanate, polycarbonate diol, 2,2-bis(hydroxymethyl) butyric acid and 1,4-butanediol. The products with the silane content varied from 1.2 to 16.5 wt% were dispersed in water after neutralization. The effect of the silane diol on the particle size and morphology of the WPU dispersion was studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. X-ray photoelectron spectroscopy (XPS) characterization was carried out on the coating film of the WPU, revealing that the long flexible side chain is favorable for the silane components to emigrate toward the film surface and crosslink during the film formation process. As a result, both the surface contact angle to water and water adsorption of the WPU coating films increased with the silane content. Furthermore, the mechanical properties including the modulus and tensile strength of the films were also improved by the incorporation of silane diol.

  1. Polyurethane foam for roadway stabilization NH route 129, Loudon, NH.

    Science.gov (United States)

    2016-12-12

    This report summarizes the evaluation of the performance of polyurethane foam as a method of roadway : stabilization for a rural roadway experiencing substantial frost heaving. : NHDOT is responsible for many roads which have evolved from gravel road...

  2. Soybean-oil-based waterborne polyurethane dispersions: effects of polyol functionality and hard segment content on properties.

    Science.gov (United States)

    Lu, Yongshang; Larock, Richard C

    2008-11-01

    The environmentally friendly vegetable-oil-based waterborne polyurethane dispersions with very promising properties have been successfully synthesized without difficulty from a series of methoxylated soybean oil polyols (MSOLs) with different hydroxyl functionalities ranging from 2.4 to as high as 4.0. The resulting soybean-oil-based waterborne polyurethane (SPU) dispersions exhibit a uniform particle size, which increases from about 12 to 130 nm diameter with an increase in the OH functionality of the MSOL from 2.4 to 4.0 and decreases with increasing content of the hard segments. The structure and thermophysical and mechanical properties of the resulting SPU films, which contain 50-60 wt % MSOL as renewable resources, have been studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and mechanical testing. The experimental results reveal that the functionality of the MSOLs and the hard segment content play a key role in controlling the structure and the thermophysical and mechanical properties of the SPU films. These novel films exhibit tensile stress-strain behavior ranging from elastomeric polymers to rigid plastics and possess Young's moduli ranging from 8 to 720 MPa, ultimate tensile strengths ranging from 4.2 to 21.5 MPa, and percent elongation at break values ranging from 16 to 280%. This work has addressed concerns regarding gelation and higher cross-linking caused by the high functionality of vegetable-oil-based polyols. This article reports novel environmentally friendly biobased SPU materials with promising applications as decorative and protective coatings.

  3. Thermal stability of novel polyurethane adhesives investigated by TGA

    Directory of Open Access Journals (Sweden)

    Mariusz Mamiński

    2014-05-01

    Full Text Available The objective of the work was an assessment of thermal stability of novel polyurethane wood adhesives by means of TGA. Hyperbranched polyglycerols of various structures were used as polyol components cured with polymeric methylenediphenyldiisocyanate (PMDI or polymeric hexamethylenediisocyanate (PHDI. Resultant adhesives were thermally degraded in temperature range 20 - 500ºC. Performance of polyurethane based on fully aliphatic polyglycerol was inferior to those based on polyglycerols bearing aromatic moieties. The differences in 50%-weight loss temperature achieving 27 - 39°C as well as residual weights at 480 ºC indicate the contribution of aromatic units presence within the macromonomer structure to increased thermal stability of polyurethane upon thermal degradation. Furthermore, temperature of 50% weight loss revealed that thermal stability of the developed hyperbranched polyglycerol-based adhesives was comparable to that of the commercial PUR adhesive.

  4. Micelle-template synthesis of hollow silica spheres for improving water vapor permeability of waterborne polyurethane membrane

    Science.gov (United States)

    Bao, Yan; Wang, Tong; Kang, Qiaoling; Shi, Chunhua; Ma, Jianzhong

    2017-04-01

    Hollow silica spheres (HSS) with special interior spaces, high specific surface area and excellent adsorption and permeability performance were synthesized via micelle-template method using cetyl trimethyl ammonium bromide (CTAB) micelles as soft template and tetraethoxysilane (TEOS) as silica precursor. SEM, TEM, FT-IR, XRD, DLS and BET-BJH were carried out to characterize the morphology and structure of as-obtained samples. The results demonstrated that the samples were amorphous with a hollow structure and huge specific surface area. The growth of HSS was an inward-growth mechanism along template. Notably, we have provided a new and interesting fundamental principle for HSS materials by precisely controlling the ethanol-to-water volume ratio. In addition, the as-obtained HSS were mixed with waterborne polyurethane (WPU) to prepare WPU/HSS composite membrane. Various characterizations (SEM, TEM, FT-IR and TGA) revealed the morphology, polydispersity and adherence between HSS and WPU. Performance tests showed that the introduction of HSS can improve the water vapor permeability of composite membrane, promoting its water resistance and mechanical performance at the same time.

  5. Synthesis of Waterborne Polyurethane by the Telechelic α,ω-Di(hydroxypoly(n-butyl acrylate

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2018-02-01

    Full Text Available A key for the preparation of polyacrylate-based polyurethane is the synthesis of hydroxyl-terminated polyacrylate. To our knowledge, exactly one hydroxyl group of every polyacrylate chain has not been reported. The hydroxyl-terminated poly(butyl acrylate (PBA has been successfully synthesized by degenerative iodine transfer polymerization (DITP of the n-butyl acrylate (n-BA using 4,4′-azobis(4-cyano-1-pentanol (ACPO and diiodoxylene (DIX as initiator and chain transfer agent, respectively, and subsequently substituted reaction of the iodine-terminated PBA with β-mercaptoethanol in alkaline condition. The latter reaction was highly efficient, and the terminal iodine at the end of polymer chains were almost quantitatively transformed to a hydroxyl group. 2,2′-Azobis(isobutyronitrile (AIBN and ACPO were used as initiators in the DITPs of n-BA. The results demonstrated that they had a significant influence on the terminal groups of the formed polymer chains. The structure, molecular weight, and molecular weight distribution of the hydroxyl-terminated PBA have been studied by 1H, 13C NMR, and GPC results. The components of hydroxyl-terminated PBA were determined by MALDI-TOF MS spectra, and their formation is discussed. The broad molecular weight distribution of the PBA and the difference in the polymerization behaviors from typical living radical polymerization are explained based on the results of 1H NMR and MALDI-TOF MS spectra. The hydroxyl-terminated PBA has been successfully used in the preparation of PBA-based polyurethane dispersions (PUDs. The aqueous PUDs were stable, and based on the DSC results it can be said that the miscibility of hard segments with PBA chains was improved.

  6. Thermal stability of segmented polyurethane elastomers reinforced by clay particles

    Directory of Open Access Journals (Sweden)

    Pavličević Jelena

    2009-01-01

    Full Text Available The aim of this work was to determine the influence of clay nanoparticles on thermal properties of segmented polyurethanes based on hexamethylene- diisocyanate, aliphatic polycarbonate diol and 1,4-butanediol as chain extender. The organically modified particles of montmorillonite and bentonite were used as reinforcing fillers. The structure of elastomeric materials was varied either by diol type or chain extender content. The ratio of OH groups from diol and chain extender (R was either 1 or 10. Thermal properties of prepared materials were determined using modulated differential scanning calorimetry (MDSC. Thermal stability of obtained elastomers has been studied by simultaneously thermogravimetry coupled with DSC. The glass transition temperature, Tg, of soft segments for all investigated samples was about -33°C. On the basis of DTG results, it was concluded that obtained materials were very stable up to 300°C.

  7. Composites prepared from the waterborne polyurethane cationomers-modified graphene. Part I. Synthesis, structure, and physicochemical properties

    Czech Academy of Sciences Publication Activity Database

    Król, P.; Król, B.; Pielichowska, K.; Špírková, Milena

    2015-01-01

    Roč. 293, č. 2 (2015), s. 421-431 ISSN 0303-402X R&D Projects: GA ČR(CZ) GA13-06700S Institutional support: RVO:61389013 Keywords : polyurethane films * surface structure * AFM microscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.890, year: 2015

  8. Effect of melamine phosphate on the thermal stability and flammability of bio-based polyurethanes

    International Nuclear Information System (INIS)

    Yakushin, Vladimir; Sevastyanova, Irina; Vilsone, Dzintra; Avots, Andris

    2016-01-01

    The effect of melamine phosphate (MP) on the thermal stability of bio-based polyurethane and the flammability parameters of wood samples with polyurethane coatings was studied. Thermogravimetric analysis and cone calorimeter test at a heat flux of 35 kW/m 2 were used for this purpose. The main characteristics of the thermal stability and flammability of the coating with addition of MP were compared with the characteristics of analogous coatings with addition of ammonium polyphosphate (APP), as well as APP in combination with melamine. It was found that the use of MP as an intumescent additive allows a considerable decrease of most of the flammability parameters of the polyurethane based on tall oil fatty acids, like APP. To reach the maximum effect, it is enough to load in the polyurethane 20% of MP. In contrast to APP, MP reduces also the smoke release of the samples. Using MP in combination with APP at definite weight ratios, it is possible to essentially reduce the flammability parameters of polyurethane coatings, such as PHRR, THR and MARHE. (paper)

  9. Hydrolytic stability of polycarbonate-based polyurethane elastomers tested in physiologically simulated conditions

    Czech Academy of Sciences Publication Activity Database

    Serkis, Magdalena; Špírková, Milena; Poreba, Rafal; Hodan, Jiří; Kredatusová, Jana; Kubies, Dana

    2015-01-01

    Roč. 119, September (2015), s. 23-34 ISSN 0141-3910 R&D Projects: GA ČR(CZ) GA13-06700S Institutional support: RVO:61389013 Keywords : polyurethane * elastomer * hydrolytic stability Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.120, year: 2015

  10. The influence of polyol type on cell geometry and the thermal stability of polyurethane foams

    Directory of Open Access Journals (Sweden)

    Prendžov Slobodan J.

    2006-01-01

    Full Text Available The aim of this study was to examine the influence of substituting defined amounts of polyol Voranol 3322 by polyol Voranol CP 1055 on the cell geometry and thermal stability of the synthesized flexible polyurethane foams. The influence of the amount of antipyrene on the cell geometry and their thermal stability was also investigated. The following components were used in the synthesis of the polyurethanes: a mixture of two polyols (Voranol 3322 with the hydroxyl number 47 mg KOH/g, mean molecular mass 3400 and Voranol CP 1055 with the hydroxyl number 156 mg KOH/g, mean molecular mass 1000, toluene discarnate as the isocyanate component, a combination of an organic-metallic compound and a tertiary amine as catalysts, surfactant and water as the coreactant. The thermal stability was determined by thermogravimetric analysis (in a nitrogen atmosphere. The cell geometry was analyzed by optical microscopy. Examination of the cell geometry revealed different cell shapes. The form factor as an indicator of cell deviation from spherical shape increased (more round forms were observed with increasing amount of Voranol CP 1055. The TG examination showed that specimens with 6 and 8 g of Voranol 3322 substituted by Voranol CP 1055 completely degraded at 350 °C, while foams with 10 and 12 g of Voranol 3322 substituted by Voranol CP 1055 displayed lower mass loss at higher temperatures and had residual masses of 46 % and 43 % at 600°C respectively. The addition of antipyrene in an amount of 1% (based on the amount of polyol contributed to improved thermal stability, no visible color change of the specimen tested at 210°C for 40 minutes, and to rounder cell forms. Considering the obtained results it can be concluded that an increase in the amount of Voranol CP 1055 yielded more spherically shaped cells and better thermal stability of the synthesized flexible polyurethane foams. The addition of antipyrene improves the thermal stability and the cell geometry.

  11. Study on the Permeability Characteristics of Polyurethane Soil Stabilizer Reinforced Sand

    Directory of Open Access Journals (Sweden)

    Jin Liu

    2017-01-01

    Full Text Available A polymer material of polyurethane soil stabilizer (PSS is used to reinforce the sand. To understand the permeability characteristics of PSS reinforced sand, a series of reinforcement layer form test, single-hole permeability test, and porous permeability test of sand reinforced with PSS have been performed. Reinforcement mechanism is discussed with scanning electron microscope images. The results indicated that the permeability resistance of sand reinforced with polyurethane soil stabilizer is improved through the formation of reinforcement layer on the sand surface. The thickness and complete degree of the reinforcement layer increase with the increasing of curing time and PSS concentration. The water flow rate decreases with the increasing of curing time or PSS concentration. The permeability coefficient decreases with the increasing of curing time and PSS concentration and increases with the increasing of depth in specimen. PSS fills up the voids of sand and adsorbs on the surface of sand particle to reduce or block the flowing channels of water to improve the permeability resistance of sand. The results can be applied as the reference for chemical reinforcement sandy soil engineering, especially for surface protection of embankment, slope, and landfill.

  12. Preparation of polyurethane/montmorillonite nanocomposites by solution: characterization using low-field NMR and study of thermal stability

    International Nuclear Information System (INIS)

    Silva, Marcos Anacleto da; Tavares, Maria Ines B.

    2009-01-01

    Polyurethanes (PU) are important and versatile class of polymer materials, especially because of their desirable properties, such as high abrasion resistance, tear strength, excellent shock absorption, flexibility and elasticity. However, there also exist some disadvantages, for example, low thermal stability and barrier properties. To overcome the disadvantages, research on novel polyurethane/clay nanocomposites has been carried out. The investigation of the structure of polyurethane/clay nanocomposites has been mostly done by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this work, PU/clay films were prepared by solution, and the obtained nanocomposites were characterized by XRD and low-field nuclear magnetic resonance (NMR). Low field NMR measurements were able to provide important information on molecular dynamics of the polymeric nanocomposites PU/OMMT. In addition, they also confirmed the results obtained by XRD. The thermal stability was determined by thermogravimetric analysis (TGA). (author)

  13. Improved thermal stability and wettability behavior of thermoplastic polyurethane / barium metaborate composites

    International Nuclear Information System (INIS)

    Baştürka, Emre; Madakbaş, Seyfullah; Kahraman, Memet Vezir

    2016-01-01

    In this paper, it was targeted to the enhance thermal stability and wettability behavior of thermoplastic polyurethane (TPU) by adding barium metaborate. TPU-Barium metaborate composites were prepared by adding various proportions of barium metaborate to TPU. The chemical structures of the composites were characterised by fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. All prepared composites have extremely high Tg and thermal stability as determined from DSC and TGA analysis. All composite materials have the Tg ranging from 15 to 35 °C. The surface morphologies of the composites were investigated by a scanning electron microscopy. Mechanical properties of the samples were characterized with stress-strain test. Hydrophobicity of the samples was determined by the contact angle measurements. The obtained results proved that thermal, hydrophobic and mechanical properties were improved. (author)

  14. Improved thermal stability and wettability behavior of thermoplastic polyurethane / barium metaborate composites

    Energy Technology Data Exchange (ETDEWEB)

    Baştürka, Emre; Madakbaş, Seyfullah; Kahraman, Memet Vezir, E-mail: smadakbas@marmara.edu.tr [Department of Chemistry, Marmara University, Istanbul (Turkey)

    2016-03-15

    In this paper, it was targeted to the enhance thermal stability and wettability behavior of thermoplastic polyurethane (TPU) by adding barium metaborate. TPU-Barium metaborate composites were prepared by adding various proportions of barium metaborate to TPU. The chemical structures of the composites were characterised by fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. All prepared composites have extremely high Tg and thermal stability as determined from DSC and TGA analysis. All composite materials have the Tg ranging from 15 to 35 °C. The surface morphologies of the composites were investigated by a scanning electron microscopy. Mechanical properties of the samples were characterized with stress-strain test. Hydrophobicity of the samples was determined by the contact angle measurements. The obtained results proved that thermal, hydrophobic and mechanical properties were improved. (author)

  15. The impact of conditions mimicking physiological environment on the thermal stability of aliphatic polycarbonate-based polyurethane elastomers

    Czech Academy of Sciences Publication Activity Database

    Špírková, Milena; Kredatusová, Jana; Hodan, Jiří

    2017-01-01

    Roč. 128, č. 3 (2017), s. 1699-1709 ISSN 1388-6150 R&D Projects: GA ČR(CZ) GA13-06700S Institutional support: RVO:61389013 Keywords : polyurethane * thermal stability * thermogravimetric analysis Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.953, year: 2016

  16. Effect of γ-radiation sterilization on the stability of polyurethane potting compounds based on castor oil/SMDI and caprolactone polyol/SMDI, used for hollow fibre haemodialyzer

    International Nuclear Information System (INIS)

    Jayabalan, M.; Lizymol, P.P.

    1997-01-01

    Stability of polyurethane potting compounds based on castor oil/SMDI and caprolactone polyol/SMDI in repeated gamma radiation sterilization was studied. Radiation-induced degradation and leaching of low molecular weight fragments are higher in castor oil based polyurethane than in caprolactone polyol based polyurethane. For castor oil and caprolactone polyol based polyurethanes degradation increases up to 5 Mrad dose of sterilization. Further increase of dose of sterilization decreases leaching in caprolactone polyol based polyurethane which has resulted from secondary reactions leading to crosslinking. In the case of castor oil based polyurethane such crosslinks undergo cleavage at 10 Mrad dose of sterilization. (author)

  17. Nanostructured polyurethane perylene bisimide ester assemblies with tuneable morphology and enhanced stability

    Science.gov (United States)

    Zhang, Xiaoxiao; Gong, Tingyuan; Chi, Hong; Li, Tianduo

    2018-03-01

    Size control has been successfully achieved in inorganic materials, but it remains a challenge in polymer nanomaterials due to their polydispersity. Here, we report a facile approach to tailor the diameters of polyurethane (PU) nanoparticles (490 nm, 820 nm and 2.1 µm) via perylene bisimide (PBI) assisted self-assembly. The formed morphologies such as spindle, spherical and core-shell structures depend on the ratio of PBI and polymer concentrations. It is shown that the formation of PU nanoparticles is directed by π-π stacking of PBI and the morphology transition is not only affected by the amount of PBI incorporated, but also influenced by solvent, which controls the initial evaporation balance. Furthermore, the prepared PUs exhibit retained optical stability and enhanced thermal stability. The PUs, designed to have conjugated PBI segments in backbones, were synthesized via ring-opening and condensation reactions. Compared with the neat PU, gel permeation chromatography shows narrower molecular weight distribution. Fluorescence spectra and ultraviolet-visible spectra indicate retained maximum emission wavelength of PBI at 574 nm and 5.2% quantum yields. Thermo-gravimetric analysis and differential scanning calorimetry reveal 79°C higher decomposition temperature and 22°C higher glass transition temperature. This study provides a new way to fabricate well-defined nanostructures of functionalized PUs.

  18. Nanostructured polyurethane perylene bisimide ester assemblies with tuneable morphology and enhanced stability.

    Science.gov (United States)

    Zhang, Xiaoxiao; Gong, Tingyuan; Chi, Hong; Li, Tianduo

    2018-03-01

    Size control has been successfully achieved in inorganic materials, but it remains a challenge in polymer nanomaterials due to their polydispersity. Here, we report a facile approach to tailor the diameters of polyurethane (PU) nanoparticles (490 nm, 820 nm and 2.1 µm) via perylene bisimide (PBI) assisted self-assembly. The formed morphologies such as spindle, spherical and core-shell structures depend on the ratio of PBI and polymer concentrations. It is shown that the formation of PU nanoparticles is directed by π-π stacking of PBI and the morphology transition is not only affected by the amount of PBI incorporated, but also influenced by solvent, which controls the initial evaporation balance. Furthermore, the prepared PUs exhibit retained optical stability and enhanced thermal stability. The PUs, designed to have conjugated PBI segments in backbones, were synthesized via ring-opening and condensation reactions. Compared with the neat PU, gel permeation chromatography shows narrower molecular weight distribution. Fluorescence spectra and ultraviolet-visible spectra indicate retained maximum emission wavelength of PBI at 574 nm and 5.2% quantum yields. Thermo-gravimetric analysis and differential scanning calorimetry reveal 79°C higher decomposition temperature and 22°C higher glass transition temperature. This study provides a new way to fabricate well-defined nanostructures of functionalized PUs.

  19. Acid monomer analysis in waterborne polymer systems by targeted labeling of carboxylic acid functionality, followed by pyrolysis - gas chromatography.

    Science.gov (United States)

    Brooijmans, T; Okhuijsen, R; Oerlemans, I; Schoenmakers, P J; Peters, R

    2018-05-14

    Pyrolysis - gas chromatography - (PyGC) is a common method to analyse the composition of natural and synthetic resins. The analysis of acid functionality in, for example, waterborne polyacrylates and polyurethanes polymers has proven to be difficult due to solubility issues, inter- and intramolecular interaction effects, lack of detectability in chromatographic analysis, and lack of thermal stability. Conventional analytical techniques, such as PyGC, cannot be used for the direct detection and identification of acidic monomers, due to thermal rearrangements that take place during pyrolysis. To circumvent this, the carboxylic acid groups are protected prior to thermal treatment by reaction with 2-bromoacetophenone. Reaction conditions are investigated and optimised wrt. conversion measurements. The aproach is applied to waterborne polyacryalates and the results are discussed. This approach enables identification and (semi)quantitative analysis of different acid functionalities in waterborne polymers by PyGC. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Road Maintenance Experience Using Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization as Ground Rehabilitation

    Science.gov (United States)

    Fakhar, A. M. M.; Asmaniza, A.

    2016-07-01

    There are many types of ground rehabilation and improvement that can be consider and implement in engineering construction works for soil improvement in order to prevent road profile deformation in later stage. However, when comes to road maintenance especially on operated expressways, not all method can be apply directly as it must comply to opreation's working window and lane closure basis. Key factors that considering ideal proposal for ground rehabilitation are time, cost, quality and most importantly practicality. It should provide long lifespan structure in order to reduce continuous cycle of maintenance. Thus, this paper will present two approaches for ground rehabilitation, namely Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization. The first approach is an injection system which consists two-parts chemical grout of Isocynate and Polyol when mixed together within soil structure through injection will polymerized with volume expansion. The strong expansion of grouting causes significant compression and compacting of the surrounding soil and subsequently improve ground properties and uplift sunken structure. The later is a cold in-place recyclying whereby mixture process that combines in-situ soil materials, cement, white powder (alkaline) additive and water to produce hard yet flexible and durable ground layer that act as solid foundation with improved bearing capacity. The improvement of the mechanical behaviour of soil through these two systems is investigated by an extensive testing programme which includes in-situ and laboratory test in determining properties such as strength, stiffness, compressibility, bearing capacity, differential settlement and etc.

  1. 合成革用水性聚氨酯树脂的改性研究进展%New Research Progress in the Modification Technology of Waterborne Polyurethane Resin Used for the Manufacture of Synthetic Leather

    Institute of Scientific and Technical Information of China (English)

    杨建军; 张建安; 吴庆云; 吴明元

    2013-01-01

    In this paper, the characteristics of waterborne polyurethane ( WPU) and its research progress of new technologies on modifying WPU resin were introduced. The main problems in the production and application of WPU resin used for the manufacture of synthetic leather were discussed. However, since the hydrophilic group is introduced into the molecules, WPU is weak in water resistance, solvent resistance, water vapor permeability, compatibility and rate of drying, hence the necessity of modifying WPU, such as the acrylate modification, organic silicon modification, organic fluorine modification, vegetable oil modification, epoxy resin modification, nanometer materials modification,and hyperbranched polymer modification,etc. The use of radiation technology, including radiation polymerization, crosslinking and curing, in copolymer latex is reviewed in the paper. The likely future trends of the modification design of WPU resin used for the manufacture of synthetic leather were described.%该文介绍了水性聚氨酯的性能特点以及改性新技术的研究进展.论述了合成革用水性聚氨酯树脂在生产和应用中存在的主要问题,由于分子中引入了亲水基团,水性聚氨酯树脂在耐水性、耐溶剂性、透气透湿性、配伍性和干燥速度等方面表现较差,需要对其进行改性研究,如采用丙烯酸酯改性、有机硅改性、有机氟改性、植物油改性、环氧树脂改性、纳米材料改性和超支化聚合物改性等,并讨论了辐射聚合、交联及固化等辐射技术在共聚物乳液制备上的研究及应用.最后对合成革用水性聚氨酯树脂改性设计的发展前景作了展望.

  2. The effect of virtual cross linking on the oxidative stability and lipid uptake of aliphatic poly(urethane urea).

    Science.gov (United States)

    Thomas, Vinoy; Jayabalan, Muthu

    2002-01-01

    In vitro oxidative degradation and lipid sorption of aliphatic, low elastic modulus and virtually cross-linked poly(urethane urea)s based on 4,4' methylene bis(cyclohexyl isocyanate), hydroxy terminated poly butadiene and hexamethylene diamine were evaluated. The aged samples revealed no weight loss in the oxidation medium. The IR spectral analyses revealed the stability of unsaturated double bonds at 964 cm(-1) (characteristic for polybutadiene soft segment) with no change in peak intensity. The poly(tetramethylene glycol) (PTMG)-added poly(ether urethane urea) polymer also revealed no disappearance of IR peaks for ether and unsaturated double bonds in samples aged in vitro oxidation medium. All the polymers have shown increase in weight due to lipid up take in lipid-rich medium (palm oil) but it was rather low in Dulbecco's modified eagle medium (DMEM) cholesterol. The slight change in mechanical properties of the present polymers in oxidation and DMEM is due to the rearrangement of molecular structure with virtual cross links of hydrogen bonding (physical cross linking) without degradation and plasticization effect of lipid. The influence of these media on the rearrangement of virtual cross links has been observed. Higher the virtual cross-link density, lesser is the loss of tensile properties of poly(urethane urea)s in the oxidation medium and vice versa. On the other hand, higher the virtual cross-link density of poly(urethane urea), higher is the loss of ultimate tensile strength and stress at 100% strain and vice versa in DMEM medium.

  3. Polyurethane Foam Wound Dressing Technique for Areola Skin Graft Stabilization and Nipple Protection After Nipple-Areola Reconstruction.

    Science.gov (United States)

    Satake, Toshihiko; Muto, Mayu; Nagashima, Yu; Haga, Shoko; Homma, Yuki; Nakasone, Reiko; Kadokura, Marina; Kou, Seiko; Fujimoto, Hiroshi; Maegawa, Jiro

    2018-04-01

    We describe a new wound management technique using a soft dressing material to stabilize the areola skin graft and protect the nipple after nipple-areola reconstruction at the final stage of breast reconstruction. We introduced a center-fenestrated multilayered hydrocellular polyurethane foam dressing material that provides adequate pressure and retains a moist environment for a smooth skin graft "take." Moreover, the reconstructed nipple can be monitored at any time through the fenestrated window for adequate blood circulation. Altogether, this simple and inexpensive wound dressing technique improves the clinical outcome. Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  4. Waterborne UV coating for industrial applications

    International Nuclear Information System (INIS)

    Bhattacharya, I.N.

    2007-01-01

    (Full Text): Solvent borne industrial coatings are being replaced by environment friendly coatings like Ultra Violet (UV) or Electron Beam (Eb) cured coatings, Powder coatings and Waterborne coatings. Waterborne systems enjoy the biggest share from this shift. UV and EB coatings provide the advantages of instant cure at room temperature, high scratch and abrasion resistance combined with excellent chemical resistance. Polyurethane (PU) chemistry is the dominant chemistry in Industrial coatings as they provide a very high level of performance. Most PU coatings are solvent based 2-component systems comprising of a resin and a cross linker. Polyurethane dispersions (PUD) in water in single pack are available but mainly addresses the Do It Yourself (DIY) market because of their slow drying speeds. Performance of PUD in most cases is inferior to solvent borne 2-component PU systems.Therefore the combination of PU dispersion and UV/EB curable technology has led to new innovative waterborne polymers called UV curable polyurethane dispersions (UVPUD). UVPUD are zero VOC systems as they are coalescent free. They are higher in molecular weight than standard UV curable products resulting in lower shrinkage coatings and provide good adhesion to substrates. Their low-viscosity makes them suitable for application by spray, curtain coater and even roller coater, without having to use monomers. UVPUD display superior chemical and mechanical properties necessary to protect high quality surface from the challenging usage conditions. UVPUD resins are therefore tailor-made to address performance needs like excellence in outdoor durability, scratch resistance, stain resistance, adhesion etc. UVPUD technology is now growing rapidly in industrial coatings for applications such as resilient flooring, wooden parquet flooring, automotive interior plastics, mobile phones etc. (Author)

  5. Studies on the effect of virtual crosslinking on the hydrolytic stability of novel aliphatic polyurethane ureas for blood contact applications.

    Science.gov (United States)

    Thomas, V; Jayabalan, M

    2001-07-01

    The effect of virtual crosslinking on the hydrolytic stability of completely aliphatic novel poly(urethane ureas), HFL9-PU1 (hard-segment content 57.5%) and HFL13-PU2 (hard-segment content 67.9%) based on 4,4'-methylene bis(cyclohexyl isocyanate) (H(12)MDI)-hydroxy-terminated polybutadiene-1,6-hexamethylene diamine, was studied. Fourier transform infrared-attenuated total reflectance and wide-angle X-ray diffraction studies revealed hydrogen-bonding interaction and microphase separation and formation of crystallites by short- and long-range ordering in hard-segment domains. Three-dimensional networks from hydrogen bonding in the present polymers lead to virtually crosslinking and insolubility. These polymers were noncytotoxic to L929 fibroblast cells. The hemolytic potential is below the accepted limit. The studies on in vitro biostability in Ringer's solution, phosphate buffered saline, and papain enzyme revealed no weight loss. The infrared spectral studies revealed changes in the surface, especially on HFL9-PU1 aged in Ringer's solution and phosphate buffered saline, and no changes when aged in papain. The marginal changes noticed in tensile properties were attributed to the changes in degree of hydrogen bonding and associated rearrangement of molecular structure in the bulk. The results revealed that the lesser the crosslinking in virgin polymer, the higher the crosslinking in aged polymer and vice versa. Increased crosslinking during aging provided increased tensile properties in the aged polymer over the virgin polymer and vice versa. For comparison, an aliphatic polyetherurethane urea (HFL16-PU3) was also synthesized using poly(oxy tetra methylene glycol) in addition to the above reactants. Though both HFL9-PU1 and HFL16-PU3 contained the same hard-segment content, the aged sample of the latter showed decreased tensile properties with increased crosslinking during aging in contrast to the former. This was attributed to less microphase separation in the

  6. Biodegradable polyurethane nanocomposites containing dexamethasone for ocular route

    International Nuclear Information System (INIS)

    Rodrigues da Silva, Gisele; Silva-Cunha, Armando da; Behar-Cohen, Francine; Ayres, Eliane; Orefice, Rodrigo L.

    2011-01-01

    The treatment of posterior segment ocular diseases, such as uveitis, by using eye drops and oral drugs is usually not effective due to the body's natural barriers to drug penetration. In this study, ocular implants to treat uveitis were synthesized by incorporating dexamethasone acetate, an important type of corticoid used in the treatment of some uveitis, into a biodegradable polyurethane containi clay nanoparticles. Biodegradable polyurethane nanocomposites having poly(caprolactone) oligomers as soft segments were obtained by delaminating clay particles within a polyurethane aqueous dispersion. The drug was incorporated into the polymer by dispersing it in the waterborne polyurethane followed by a drying step. Nanoparticles derived from clay were demonstrated to be able to tailor the mechanical properties of polyurethanes to achieve values that can match the properties of ocular soft tissues. Infrared spectra (FTIR) showed that the presence of clay particles was able to change the microphase separation process typical of polyurethanes. X-ray diffraction and small angle x-ray scattering (SAXS) results were explored to show that the incorporation of both dexamethasone acetate and nanocomponents derived from clay led to a less defined two-phase polyurethane. The presence of clay nanoparticles increased the rate of drug release measured in vitro. Human retinal pigment epithelial cells (ARPE-19) were cultured in contact with polyurethanes and polyurethane nanocomposites, and the viability of them (evaluated by using MTT assay after 7 days) showed that no toxic components were released from polyurethanes containing no drugs during the test.

  7. Biodegradable polyurethane nanocomposites containing dexamethasone for ocular route

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues da Silva, Gisele [Federal University of Sao Joao Del Rei, School of Pharmacy, Divinopolis, Minas Gerais (Brazil); Silva-Cunha, Armando da [Federal University of Minas Gerais, School of Pharmacy, Belo Horizonte, Minas Gerais (Brazil); Behar-Cohen, Francine [INSERM, Physiopathology of ocular diseases: Therapeutic innovations, Institut des Cordeliers, Paris (France); Laboratoire d' Innovations Therapeutiques, Fondation Rothschild, Paris (France); Universite Rene Descartes, Hotel Dieu University Hospital, Paris (France); Ayres, Eliane [Federal University of Minas Gerais, Department of Metallurgical and Materials Engineering, Belo Horizonte, Minas Gerais (Brazil); Orefice, Rodrigo L., E-mail: rorefice@demet.ufmg.br [Federal University of Minas Gerais, Department of Metallurgical and Materials Engineering, Belo Horizonte, Minas Gerais (Brazil)

    2011-03-12

    The treatment of posterior segment ocular diseases, such as uveitis, by using eye drops and oral drugs is usually not effective due to the body's natural barriers to drug penetration. In this study, ocular implants to treat uveitis were synthesized by incorporating dexamethasone acetate, an important type of corticoid used in the treatment of some uveitis, into a biodegradable polyurethane containi clay nanoparticles. Biodegradable polyurethane nanocomposites having poly(caprolactone) oligomers as soft segments were obtained by delaminating clay particles within a polyurethane aqueous dispersion. The drug was incorporated into the polymer by dispersing it in the waterborne polyurethane followed by a drying step. Nanoparticles derived from clay were demonstrated to be able to tailor the mechanical properties of polyurethanes to achieve values that can match the properties of ocular soft tissues. Infrared spectra (FTIR) showed that the presence of clay particles was able to change the microphase separation process typical of polyurethanes. X-ray diffraction and small angle x-ray scattering (SAXS) results were explored to show that the incorporation of both dexamethasone acetate and nanocomponents derived from clay led to a less defined two-phase polyurethane. The presence of clay nanoparticles increased the rate of drug release measured in vitro. Human retinal pigment epithelial cells (ARPE-19) were cultured in contact with polyurethanes and polyurethane nanocomposites, and the viability of them (evaluated by using MTT assay after 7 days) showed that no toxic components were released from polyurethanes containing no drugs during the test.

  8. Síntesis y caracterización de adhesivos reposicionables de poliuretano dispersos en agua, obtenidos a partir de aceite de castor maleinizado Synthesis and characterization of pressure-sensitive adhesives of waterborne polyurethane from maleinizated castor oil

    Directory of Open Access Journals (Sweden)

    Paula Mazo

    2010-06-01

    Full Text Available El presente trabajo se centró en la producción de dispersiones acuosas de poliuretano empleando el método de emulsificación por inversión de fases. Para la síntesis fueron empleados dos polioles: uno comercial tipo poliéster y el otro es aceite de castor maleinizado (MACO; dos diisocianatos, uno aromático Toluen diisocianato (TDI y otro alifático Hexametilen diisocianato (HDI, siendo poco comunes para esta aplicación. Como emulsificante interno se empleó ácido cítrico el cual es muy económico y de fácil adquisición. Como factores se evaluaron la cantidad de ácido cítrico y la relación molar de grupos isocianato a hidroxilos (NCO/OH, generando un diseño de experimentos factorial 3² y minimizando el contenido de sólidos sedimentados. Mediante la metodología de superficie de respuesta, se obtuvo una ecuación polinomial cuadrática por un análisis de regresión múltiple. Los poliuretanos formados fueron evaluados en cuanto a sus propiedades adhesivas y mecánicas (pegajosidad tack, pegajosidad en cinta loop tack, cohesión hold, pelado peel, lo que permitió clasificar el adhesivo como reposicionable, para emplearlo en etiquetas.This work focused on the production of aqueous dispersions of polyurethane using the emulsification method by phase inversion. For the synthesis two polyols were employed, viz. a commercial polyester and Maleinizated Castor Oil (MACO, with two diisocyanates: one aromatic, toluene diisocyanate (TDI and another aliphatic, hexamethylene diisocyanate (HDI, which are not common for this application. Citric acid was used as internal emulsifier which is inexpensive and readily available. The parameters were the amount of citric acid and the mole ratio of isocyanate groups to hydroxyl (NCO/OH, generating a 3² factorial design, with minimization of the sedimented solids. The surface methodology was used to obtain a quadratic polynomial equation by multiple regression analysis. Polyurethanes synthesized were

  9. Polyurethane adhesives in flat roofs

    OpenAIRE

    Bogárová Markéta; Stodůlka Jindřich; Šuhajda Karel

    2017-01-01

    It is necessary to stabilize individual layers of flat roofs, mainly because of wind suction. Apart from anchoring and surcharge, these layers can be secured by bonding. At present gluing is an indispensable and widely used stabilization method. On our market we can found many types of adhesives, most widely used are based on polyurethane. This paper focuses on problematic about stabilization thermal insulation from expanded polystyrene to vapor barrier from bitumen. One of the main issues is...

  10. Synthesis and characterization of novel fluoroalkyl-terminated hyperbranched polyurethane latex

    Science.gov (United States)

    Xu, Wei; Zhao, Weijia; Hao, Lifen; Wang, Sha; Pei, Mengmeng; Wang, Xuechuan

    2018-04-01

    Waterborne polyurethane (PU) emulsions are widely used in various fields and the demand for them is ever-increasing over the years. However, the hydrophilic chain extender inevitably bonded into the PU backbone can affect the water tolerance of PU. Thus, it is of great importance to improve PU water resistance effectively. Herein, novel fluoroalkyl-terminated hyperbranched polyurethane (HBPUF) latex was accordingly synthesized by graft reaction of perfluorohexyl ethyl alcohol and hyperbranched polyurethane (HBPU), which was previously obtained from interaction between hydroxyl-terminated hyperbranched polymer and PU prepolymer manufactured via the acetone process, as well as using neutralization, adding water, and high-speed stirring operations. We characterized the resultants and investigated its surface properties by IR, NMR, TEM, XRD, TGA, DSC, FE-SEM, AFM, XPS, and contact angle measurements, etc. IR and NMR tests confirmed that the fluorinated fragments had been grafted onto the tail end of HBPU. TEM, XRD, DSC, and FE-SEM results all accounted for the fact that there were multi-crystals in PU, HBPU and HBPUF. TGA results showed that thermal stabilities of the PU, HBPU, and HBPUF latex films were enhanced in turn. XPS and AFM analyses demonstrated that the fluorine-containing segments from the HBPUF terminals were prone to migrate and enrich on the film-air surface of the HBPUF latex film, which made water contact angle and water absorption of the HBPUF film be as 113.9° and 11.1%, respectively, compared to those of the PU film (77.8° and 136.2%). This research indicates that water resistance of the PU film can be efficiently enhanced by fluorinated polyurethane with novel fluoroalkyl-terminated hyperbranched structure.

  11. Acid–base interaction between carbon black and polyurethane molecules with different amine values: Dispersion stability of carbon black suspension for use in lithium ion battery cathodes

    International Nuclear Information System (INIS)

    Kil, Ki Chun; Kim, Gu Yeon; Cho, Chae-Woong; Lim, Myung Duk; Kim, Kijun; Jeong, Kyung-Min; Lee, Jinuk; Paik, Ungyu

    2013-01-01

    The dispersion properties of carbon black (CB) slurries as well as the accompanying electrochemical properties of Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 (NCM) electrodes were investigated by controlling the amine value of polyurethane-based dispersants. The increase in amine value of dispersants leads to an increase in adsorption level on CB surface due to a strong acid/base interaction between dispersants and CB particles, providing the improvement of steric repulsion between particles at the solid–liquid interface. This results in the enhancement of the dispersion stability of CB and the related microstructure of the electrodes. Electrochemical experiments indicated that the rate capabilities and cycle performance of the electrodes are in good agreement with dispersion properties of CB slurries. However, it was found that the excessive addition of the dispersant was deleterious to electrochemical properties because the non-adsorbed dispersants act as an electronic conduction barrier between solid phases. Therefore, it is suggested that the amine value of dispersant and tailored amount of dispersant addition can be key roles for obtaining the optimized dispersion stability of CB and the corresponding excellent electrochemical properties of the cathode

  12. Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility.

    Science.gov (United States)

    Dawlee, S; Jayabalan, Muthu

    2011-10-01

    Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.

  13. Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility

    International Nuclear Information System (INIS)

    Dawlee, S; Jayabalan, Muthu

    2011-01-01

    Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.

  14. Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Dawlee, S; Jayabalan, Muthu, E-mail: muthujayabalan@rediffmail.com [Polymer Science Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala 695 012 (India)

    2011-10-15

    Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.

  15. Effect of Hyaluronic Acid Incorporation Method on the Stability and Biological Properties of Polyurethane-Hyaluronic Acid Biomaterials

    Science.gov (United States)

    Ruiz, Amaliris; Rathnam, Kashmila R.; Masters, Kristyn S.

    2014-01-01

    The high failure rate of small diameter vascular grafts continues to drive the development of new materials and modification strategies that address this clinical problem, with biomolecule incorporation typically achieved via surface-based modification of various biomaterials. In this work, we examined whether the method of biomolecule incorporation (i.e., bulk vs. surface modification) into a polyurethane (PU) polymer impacted biomaterial performance in the context of vascular applications. Specifically, hyaluronic acid (HA) was incorporated into a poly(ether urethane) via bulk copolymerization or covalent surface tethering, and the resulting PU-HA materials characterized with respect to both physical and biological properties. Modification of PU with HA by either surface or bulk methods yielded materials that, when tested under static conditions, possessed no significant differences in their ability to resist protein adsorption, platelet adhesion, and bacterial adhesion, while supporting endothelial cell culture. However, only bulk-modified PU-HA materials were able to fully retain these characteristics following material exposure to flow, demonstrating a superior ability to retain the incorporated HA and minimize enzymatic degradation, protein adsorption, platelet adhesion, and bacterial adhesion. Thus, despite bulk methods rarely being implemented in the context of biomolecule attachment, these results demonstrate improved performance of PU-HA upon bulk, rather than surface, incorporation of HA. Although explored only in the context of PU-HA, the findings revealed by these experiments have broader implications for the design and evaluation of vascular graft modification strategies. PMID:24276670

  16. The insertion torque-depth curve integral as a measure of implant primary stability: An in vitro study on polyurethane foam blocks.

    Science.gov (United States)

    Di Stefano, Danilo Alessio; Arosio, Paolo; Gastaldi, Giorgio; Gherlone, Enrico

    2017-07-08

    Recent research has shown that dynamic parameters correlate with insertion energy-that is, the total work needed to place an implant into its site-might convey more reliable information concerning immediate implant primary stability at insertion than the commonly used insertion torque (IT), the reverse torque (RT), or the implant stability quotient (ISQ). Yet knowledge on these dynamic parameters is still limited. The purpose of this in vitro study was to evaluate whether an energy-related parameter, the torque-depth curve integral (I), could be a reliable measure of primary stability. This was done by assessing if (I) measurement was operator-independent, by investigating its correlation with other known primary stability parameters (IT, RT, or ISQ) by quantifying the (I) average error and correlating (I), IT, RT, and ISQ variations with bone density. Five operators placed 200 implants in polyurethane foam blocks of different densities using a micromotor that calculated the (I) during implant placement. Primary implant stability was assessed by measuring the ISQ, IT, and RT. ANOVA tests were used to evaluate whether measurements were operator independent (P>.05 in all cases). A correlation analysis was performed between (I) and IT, ISQ, and RT. The (I) average error was calculated and compared with that of the other parameters by ANOVA. (I)-density, IT-density, ISQ-density, and RT-density plots were drawn, and their slopes were compared by ANCOVA. The (I) measurements were operator independent and correlated with IT, ISQ, and RT. The average error of these parameters was not significantly different (P>.05 in all cases). The (I)-density, IT-density, ISQ-density, and RT-density curves were linear in the 0.16 to 0.49 g/cm³ range, with the (I)-density curves having a significantly greater slope than those regarding the other parameters (P≤.001 in all cases). The torque-depth curve integral (I) provides a reliable assessment of primary stability and shows a greater

  17. Flexible and Lightweight Pressure Sensor Based on Carbon Nanotube/Thermoplastic Polyurethane-Aligned Conductive Foam with Superior Compressibility and Stability.

    Science.gov (United States)

    Huang, Wenju; Dai, Kun; Zhai, Yue; Liu, Hu; Zhan, Pengfei; Gao, Jiachen; Zheng, Guoqiang; Liu, Chuntai; Shen, Changyu

    2017-12-06

    Flexible and lightweight carbon nanotube (CNT)/thermoplastic polyurethane (TPU) conductive foam with a novel aligned porous structure was fabricated. The density of the aligned porous material was as low as 0.123 g·cm -3 . Homogeneous dispersion of CNTs was achieved through the skeleton of the foam, and an ultralow percolation threshold of 0.0023 vol % was obtained. Compared with the disordered foam, mechanical properties of the aligned foam were enhanced and the piezoresistive stability of the flexible foam was improved significantly. The compression strength of the aligned TPU foam increases by 30.7% at the strain of 50%, and the stress of the aligned foam is 22 times that of the disordered foam at the strain of 90%. Importantly, the resistance variation of the aligned foam shows a fascinating linear characteristic under the applied strain until 77%, which would benefit the application of the foam as a desired pressure sensor. During multiple cyclic compression-release measurements, the aligned conductive CNT/TPU foam represents excellent reversibility and reproducibility in terms of resistance. This nice capability benefits from the aligned porous structure composed of ladderlike cells along the orientation direction. Simultaneously, the human motion detections, such as walk, jump, squat, etc. were demonstrated by using our flexible pressure sensor. Because of the lightweight, flexibility, high compressibility, excellent reversibility, and reproducibility of the conductive aligned foam, the present study is capable of providing new insights into the fabrication of a high-performance pressure sensor.

  18. Polyurethane adhesives in flat roofs

    Directory of Open Access Journals (Sweden)

    Bogárová Markéta

    2017-01-01

    Full Text Available It is necessary to stabilize individual layers of flat roofs, mainly because of wind suction. Apart from anchoring and surcharge, these layers can be secured by bonding. At present gluing is an indispensable and widely used stabilization method. On our market we can found many types of adhesives, most widely used are based on polyurethane. This paper focuses on problematic about stabilization thermal insulation from expanded polystyrene to vapor barrier from bitumen. One of the main issues is to calculate the exact amount of adhesive, which is required to guarantee the resistance against wind suction. In this problematic we can not find help neither in technical data sheets provided by the manufactures. Some of these data sheets contain at least information about amount of adhesive depending on location in roof plane and building height, but they do not specify the strength of such connection. It was therefore resorted to select several representatives polyurethane adhesives and their subsequent testing on specimens simulating the flat roof segment. The paper described the test methodology and results for two types of polyurethane adhesives.

  19. Characterization and properties of sepiolite/polyurethane nanocomposites

    International Nuclear Information System (INIS)

    Chen Hongxiang; Zheng Maosheng; Sun Hongying; Jia Qingming

    2007-01-01

    In situ polymerization method is employed to prepare sepiolite/polyurethane nanocomposite. The morphology and the dispersion of sepiolite in polyurethane have been characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and Fourier transform infrared spectroscopy. The results show the sepiolite is dispersed homogeneously in the polyurethane matrix at a nanometer scale. The tensile test shows that the tensile strength and elongation at break for the nanocomposites increase with the addition of sepiolite as compared to those of the pure polyurethane. The TGA analysis reveals that the addition of nanofillers results in the higher thermal stability

  20. Waterborne zoonotic helminthiases.

    Science.gov (United States)

    Nithiuthai, Suwannee; Anantaphruti, Malinee T; Waikagul, Jitra; Gajadhar, Alvin

    2004-12-09

    This review deals with waterborne zoonotic helminths, many of which are opportunistic parasites spreading directly from animals to man or man to animals through water that is either ingested or that contains forms capable of skin penetration. Disease severity ranges from being rapidly fatal to low-grade chronic infections that may be asymptomatic for many years. The most significant zoonotic waterborne helminthic diseases are either snail-mediated, copepod-mediated or transmitted by faecal-contaminated water. Snail-mediated helminthiases described here are caused by digenetic trematodes that undergo complex life cycles involving various species of aquatic snails. These diseases include schistosomiasis, cercarial dermatitis, fascioliasis and fasciolopsiasis. The primary copepod-mediated helminthiases are sparganosis, gnathostomiasis and dracunculiasis, and the major faecal-contaminated water helminthiases are cysticercosis, hydatid disease and larva migrans. Generally, only parasites whose infective stages can be transmitted directly by water are discussed in this article. Although many do not require a water environment in which to complete their life cycle, their infective stages can certainly be distributed and acquired directly through water. Transmission via the external environment is necessary for many helminth parasites, with water and faecal contamination being important considerations. Human behaviour, particularly poor hygiene, is a major factor in the re-emergence, and spread of parasitic infections. Also important in assessing the risk of infection by water transmission are human habits and population density, the prevalence of infection in them and in alternate animal hosts, methods of treating sewage and drinking water, and climate. Disease prevention methods, including disease surveillance, education and improved drinking water treatment are described.

  1. Szycher's handbook of polyurethanes

    National Research Council Canada - National Science Library

    Szycher, M

    2013-01-01

    .... Filled with tables, charts, and photographs, it includes new data on green polyurethanes, automotive applications, new coatings, new manufacturing equipment, new health-care uses, and other topics...

  2. The influence of the length of the degradable segment on the functional properties and hydrolytic stability of multi-component polyurethane elastomeric films

    Czech Academy of Sciences Publication Activity Database

    Špírková, Milena; Hodan, Jiří; Kobera, Libor; Kredatusová, Jana; Kubies, Dana; Machová, Luďka; Poreba, Rafal; Serkis, Magdalena; Zhigunov, Alexander; Kotek, Jiří

    2017-01-01

    Roč. 137, March (2017), s. 216-228 ISSN 0141-3910 R&D Projects: GA ČR(CZ) GA13-06700S Institutional support: RVO:61389013 Keywords : polyurethane elastomer * lactide * hydrolytic degradation Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.386, year: 2016

  3. Radiation-resistance of polyurethane pipes for cooling liquid in BES III

    International Nuclear Information System (INIS)

    Li Xunfeng; Zheng Lifang; Ji Quan; Wu Ping; Wang Li

    2009-01-01

    Gamma ray radiation and neutron radiation are predominant in the working conditions of BES III, and the radiation-resistance aging of polyurethane pipes is very important in this condition, as the pipes of cooling liquid for beam pipe and SCQ (superconducting quadrupole) vacuum pipe in BESIII. Polyester polyurethane pipes and polyether polyurethane pipes were irradiated by gamma ray and neutron. The radiation doses were as much as ten years' doses in BES. Pressure test, FTIR and thermal analysis were used to study the radiation-resistance of these two kinds of polyurethane pipes. The results show that the radiation-resistance and thermal stability of polyester polyurethane pipes are prior to those of polyether polyurethane pipes, and the pressure resistance of polyester polyurethane pipes is almost maintained after the irradiation by gamma ray and neutron, but the polyether polyurethane pipes can be aged and ruptured after the irradiation by neutron. (authors)

  4. Polyurethane Filler for Electroplating

    Science.gov (United States)

    Beasley, J. L.

    1984-01-01

    Polyurethane foam proves suitable as filler for slots in parts electroplated with copper or nickel. Polyurethane causes less contamination of plating bath and of cleaning and filtering tanks than wax fillers used previously. Direct cost of maintenance and indirect cost of reduced operating time during tank cleaning also reduced.

  5. Polyurethane-Foam Maskant

    Science.gov (United States)

    Bodemeijer, R.

    1985-01-01

    Brown wax previously used to mask hardware replaced with polyurethane foam in electroplating and electroforming operations. Foam easier to apply and remove than wax and does not contaminate electrolytes.

  6. Szycher's handbook of polyurethanes

    National Research Council Canada - National Science Library

    Szycher, M

    2013-01-01

    "Written as a reference for polyurethane technologists and end users, raw materials suppliers, and students in the field, this second edition covers the technical advances in the field over the past 10 years...

  7. The use of polyurethane as encapsulating method for polymer solar cells—An inter laboratory study on outdoor stability in 8 countries

    DEFF Research Database (Denmark)

    Søndergaard, Roar; Makris, Theodoros; Lianos, Panagiotis

    2012-01-01

    A new encapsulation method for organic solar cells has been tested on flexible solar modules and cells embedded in polyurethane, sandwiched between a tempered glass plate and a polycarbonate plate. Panels, each containing 10 organic solar modules/cells, were fabricated and installed for outdoor...... exposure in eight different countries for 4½ months. In order to minimize potential deviations in procedures and equipment, one person was responsible for the fabrication, installation and initial and final IV-measurements of the panels using the same equipment for all measurements and calibrations...

  8. Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold

    International Nuclear Information System (INIS)

    Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

    2014-01-01

    The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO 3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. - Highlights: • The hydroxyapatite and silver nanoparticles were grown on the polyurethane scaffold • The hydroxyapatite/polyurethane acts as reducing agent, stabilizer and matrix for Ag • The samples were well characterized by SEM-EDX, XRD, XPS, UV-visible spectroscopy • The hydroxyapatite/silver polyurethane scaffold shows antibacterial property

  9. Fabrication and Characterization of Waterborne Multi-wall Carbon Nanotube Paints

    Science.gov (United States)

    Dowty, Heather; Wang, Chyi-Shan

    2005-04-01

    The fabrication of water-borne polyurethane nanocomposites containing multi-wall nanotubes has presented a significant technological challenge to those in the polymer community. Such conductive polyurethanes are of great interest to the paint and coatings industry for use in electrical grounding and shielding. Currently, these materials are formed by strong acidic reflux of the nanotubes and subsequent dispersal in the polymer matrix. This treatment can result in significant shortening of the tubes and degradation of the resulting mechanical and electrical transport properties. Here we present an alternate technique in which various conductive and non-conductive water-soluble polymers are physi-adsorbed to the surface of the nanotube. These interactions with the nanotubes result in highly uniform suspensions of water-based urethane coatings and bulk materials. We will examine the polymer chemistry and morphologies of these nanostructured materials and the resulting thermal, electrical and mechanical properties.

  10. Polyurethane compounds having carbon nanotubes

    NARCIS (Netherlands)

    2010-01-01

    The invention relates to semi-crystalline polyurethane (PUR) compositions filled with carbon nanotubes (CNT) and having improved electrical properties, which can be obtained on the basis of water-based polyurethane/CNT mixtures. The invention further relates to a method for producing polyurethane

  11. Novel water-soluble polyurethane nanomicelles for cancer chemotherapy: physicochemical characterization and cellular activities

    Directory of Open Access Journals (Sweden)

    Khosroushahi Ahmad

    2012-01-01

    Full Text Available Abstract Background Efficient delivery of anticancer chemotherapies such as paclitaxel (PTX can improve treatment strategy in a variety of tumors such as breast and ovarian cancers. Accordingly, researches on polymeric nanomicelles continue to find suitable delivery systems. However, due to biocompatibility concerns, a few micellar nanoformulations have exquisitely been translated into clinical uses. Here, we report the synthesis of novel water-soluble nanomicelles using bioactive polyurethane (PU polymer and efficient delivery of PTX in the human breast cancer MCF-7 cells. Results The amphiphilic polyurethane was prepared through formation of urethane bounds between hydroxyl groups in poly (tetramethylene ether glycol (PTMEG and dimethylol propionic acid with isocyanate groups in toluene diisocyanate (TDI. The free isocyanate groups were blocked with phenol, while the free carboxyl groups of dimethylol propionic acid were reacted with triethylamine to attain ionic centers in the polymer backbone. These hydrophobic PTMEG blocks displayed self-assembly forming polymeric nanomicelles in water. The PTX loaded PU nanomicelles showed suitable physical stability, negative zeta potential charge (-43 and high loading efficiency (80% with low level of critical micelle concentration (CMC. In vitro drug release profile showed a faster rate of drug liberation at pH 5.4 as compared to that of pH 7.4, implying involvement of a pH-sensitive mechanism for drug release from the nanomicelles. The kinetic of release exquisitely obeyed the Higuchi model, confirming involvement of diffusion and somewhat erosion at pH 5.4. These nanomicelles significantly inhibited the growth and proliferation of the human breast cancer MCF-7 cells, leading them to apoptosis. The real time RT-PCR analysis confirmed the activation of apoptosis as result of liberation of cytochrome c in the cells treated with the PTX loaded PU nanomicelles. The comet assay analysis showed somewhat DNA

  12. Biodegradation of polyurethanes; Polyurethane no biseibutsu bunkai

    Energy Technology Data Exchange (ETDEWEB)

    Kinpara, N; Ando, M; Ohira, Z [Suzuki Motor Corp., Shizuoka (Japan); Nakajima, T; Nakahara, T [University of Tsukuba, Tsukuba (Japan)

    1997-10-01

    Different types of Polyurethane (PUR) are used for various industrial products and are used in increasing quantities every year. We experimented with biodegradation of PURs to dispose of industrial wastes. 2 strains of fungi and 1 strain of bacteria which were seemed to have the ability to degrade PURs well were isolated from various soils and waste water. These strains could degrade ester-type PUR and PUR made from a mixture of ester and ether. However, these strains could not degrade ether-type PUR. From Scanning Electron Microscopy observation, it is suggested that the microbial degradation proceeded in at least 2 patterns. 4 refs., 8 figs., 2 tabs.

  13. Novel route of synthesis for cellulose fiber-based hybrid polyurethane

    Science.gov (United States)

    Ikhwan, F. H.; Ilmiati, S.; Kurnia Adi, H.; Arumsari, R.; Chalid, M.

    2017-07-01

    Polyurethanes, obtained by the reaction of a diisocyanate compound with bifunctional or multifunctional reagent such as diols or polyols, have been studied intensively and well developed. The wide range modifier such as chemical structures and molecular weight to build polyurethanes led to designs of materials that may easily meet the functional product demand and to the extraordinary spreading of these materials in market. Properties of the obtained polymer are related to the chemical structure of polyurethane backbone. A number polyurethanes prepared from biomass-based monomers have been reported. Cellulose fiber, as a biomass material is containing abundant hydroxyl, promising material as chain extender for building hybrid polyurethanes. In previous researches, cellulose fiber was used as filler in synthesis of polyurethane composites. This paper reported a novel route of hybrid polyurethane synthesis, which a cellulose fiber was used as chain extender. The experiment performed by reacting 4,4’-Methylenebis (cyclohexyl isocyanate) (HMDI) and polyethylene glycol with variation of molecular weight to obtained pre-polyurethane, continued by adding micro fiber cellulose (MFC) with variation of type and composition in the mixture. The experiment was evaluated by NMR, FTIR, SEM and STA measurement. NMR and FTIR confirmed the reaction of the hybrid polyurethane. STA showed hybrid polyurethane has good thermal stability. SEM showed good distribution and dispersion of sorghum-based MFC.

  14. Flexible polyurethane foams

    NARCIS (Netherlands)

    2012-01-01

    Embodiments of the invention provide for a method of preparing a polyurethane foam, including reacting least one initiator comprising at least two hydroxyl groups with at least one 12-hydroxystearic acid to form at least one polyester polyol, reacting the at least one polyester polyol with at least

  15. Water permeability of pigmented waterborne coatings

    NARCIS (Netherlands)

    Donkers, P.A.J.; Huinink, H.P.; Erich, S.J.F.; Reuvers, N.J.W.; Adan, O.C.G.

    2013-01-01

    Coatings are used in a variety of applications. Last decades more and more coating systems are transforming from solvent to waterborne coating systems. In this study the influence of pigments on the water permeability of a waterborne coating system is studied, with special interest in the possible

  16. Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold.

    Science.gov (United States)

    Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

    2014-02-01

    The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. © 2013.

  17. Microbial degradation of polyurethane, polyester polyurethanes and polyether polyurethanes.

    Science.gov (United States)

    Nakajima-Kambe, T; Shigeno-Akutsu, Y; Nomura, N; Onuma, F; Nakahara, T

    1999-02-01

    Polyurethane (PUR) is a polymer derived from the condensation of polyisocyanate and polyol and it is widely used as a base material in various industries. PUR, in particular, polyester PUR, is known to be vulnerable to microbial attack. Recently, environmental pollution by plastic wastes has become a serious issue and polyester PUR had attracted attention because of its biodegradability. There are many reports on the degradation of polyester PUR by microorganisms, especially by fungi. Microbial degradation of polyester PUR is thought to be mainly due to the hydrolysis of ester bonds by esterases. Recently, polyester-PUR-degrading enzymes have been purified and their characteristics reported. Among them, a solid-polyester-PUR-degrading enzyme (PUR esterase) derived from Comamonas acidovorans TB-35 had unique characteristics. This enzyme has a hydrophobic PUR-surface-binding domain and a catalytic domain, and the surface-binding domain was considered as being essential for PUR degradation. This hydrophobic surface-binding domain is also observed in other solid-polyester-degrading enzymes such as poly(hydroxyalkanoate) (PHA) depolymerases. There was no significant homology between the amino acid sequence of PUR esterase and that of PHA depolymerases, except in the hydrophobic surface-binding region. Thus, PUR esterase and PHA depolymerase are probably different in terms of their evolutionary origin and it is possible that PUR esterases come to be classified as a new solid-polyester-degrading enzyme family.

  18. [In Situ Polymerization and Characterization of Hydroxyapatite/polyurethane Implanted Material].

    Science.gov (United States)

    Gu, Muqing; Xiao, Fengjuan; Liang, Ye; Yue, Lin; Li, Song; Li, Lanlan; Feng, Feifei

    2015-08-01

    In order to improve the interfacial bonding strength of hydroxyapatite/polyurethane implanted material and dispersion of hydroxyapatite in the polyurethane matrix, we in the present study synthesized nano-hydroxyapatite/polyurethane composites by in situ polymerization. We then characterized and analyzed the fracture morphology, thermal stability, glass transition temperature and mechanical properties. We seeded MG63 cells on composites to evaluate the cytocompatibility of the composites. In situ polymerization could improve the interfacial bonding strength, ameliorate dispersion of hydroxyapatite in the properties of the composites. After adding 20 wt% hydroxyapatite into the polyurethane, the thermal stability was improved and the glass transition temperatures were increased. The tensile strength and maximum elongation were 6.83 MPa and 861.17%, respectively. Compared with those of pure polyurethane the tensile strength and maximum elongation increased by 236.45% and 143.30%, respectively. The composites were helpful for cell adhesion and proliferation in cultivation.

  19. 21 CFR 177.1680 - Polyurethane resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyurethane resins. 177.1680 Section 177.1680 Food... of Single and Repeated Use Food Contact Surfaces § 177.1680 Polyurethane resins. The polyurethane...) For the purpose of this section, polyurethane resins are those produced when one or more of the...

  20. Root cause of waterborne diseases in Pakistan

    International Nuclear Information System (INIS)

    Hashml, H.N.; Ghumman, A.R.; Malik, N.E.

    2005-01-01

    The waterborne diseases are increasing rapidly at an alarming rate in Pakistan due to poor sanitation and unsafe drinking water supplies. This study shows that about 25 percent of all the illnesses in Lahore are due to severe cases of waterborne diseases. Unhygienic sanitation system is the root cause for this scenario. Drinking water, samples were collected from different zones of the city to find out the root cause of waterborne diseases. The samples from the distribution system serving 'Kachi Abbadies' (Underdeveloped areas) were much more contaminated, may be due to non-chlorination as compared to the water which is regularly chlorinated in posh areas of the city. Contribution of soakage pits in groundwater contamination is more significant at shallow depths. From the laboratory results it is clear that water distribution in underdeveloped areas of the city is highly contaminated and ground water available at shallow depth is also infected by microbial activities. Data collected from the different hospitals to investigate the problem shows that waterborne diseases vary their trend seasonally. Here in Pakistan, rainy season (July-August) reveals maximum number of cases of waterborne diseases. Proper sanitation and water supply systems are more essential to control the influence of waterborne diseases within the country. It is strongly recommended that reputable ways of communications are urgently required to highlight the diseases related to unsafe drinking water. (author)

  1. Preparation and characterization of polyurethane plasticizer for flexible packaging applications: Natural oils affirmed access

    Directory of Open Access Journals (Sweden)

    Mohammed A. Mekewi

    2017-03-01

    Full Text Available Developing bio-renewable feedstock for polyurethane (PU manufacturing and polymer industry as a whole has become highly desirable for both economic and environmental reasons. In this work castor oil (CO and palm olein (PO polyols were synthesized and partially used as renewable feedstock for the manufacturing of polyurethane plasticizing resin for printing ink applications. The chemical structure of the prepared polyols and polyurethanes were characterized using IR spectra and GPC and their solubility in common solvents was tested. As well, properties such as flexibility, mechanical properties, optical properties, heat seal and freeze resistance of these prepared printing inks were determined. The results indicated that the prepared printing inks from 50% synthesized polyurethane have high thermal stability, adhesion and excellent freeze resistance. The net technical properties of the new ink formulations are relatively comparable to the printing ink prepared from standard polyurethane plasticizer.

  2. Mechanical and thermal properties of sisal fiber-reinforced rubber seed oil-based polyurethane composites

    International Nuclear Information System (INIS)

    Bakare, I.O.; Okieimen, F.E.; Pavithran, C.; Abdul Khalil, H.P.S.; Brahmakumar, M.

    2010-01-01

    The development of high-performance composite materials from locally sourced and renewable materials was investigated. Rubber seed oil polyurethane resin synthesized using rubber seed monoglyceride derived from glycerolysis of the oil was used as matrix in the composite samples. Rubber seed oil-based polyurethane composite reinforced with unidirectional sisal fibers were prepared and characterized. Results showed that the properties of unidirectional fiber-reinforced rubber seed oil-based polyurethane composites gave good thermal and mechanical properties. Also, the values of tensile strengths and flexural moduli of the polyurethane composites were more than tenfold and about twofold higher than un-reinforced rubber seed oil-based polyurethane. The improved thermal stability and the scanning electron micrographs of the fracture surface of the composites were attributed to good fiber-matrix interaction. These results indicate that high-performance 'all natural products' composite materials can be developed from resources that are readily available locally.

  3. Thermal Properties of Anionic Polyurethane Composition for Leather Finishing

    Directory of Open Access Journals (Sweden)

    Olga KOVTUNENKO

    2016-09-01

    Full Text Available Thermal properties of anionic polyurethane composition mixed with collagen product and hydrophilic sodium form of montmorillonite for use in the finishing of leather were studied by thermogravimetric method. The thermal indices of processes of thermal and thermo-oxidative destruction depending on the polyurethane composition were determined. The influence of anionic polyurethane composition on thermal behavior of chromium tanned gelatin films that imitate the leather were studied. APU composition with natural compounds increases their thermal stability both in air and in nitrogen atmosphere due to the formation of additional bonds between active groups of APU, protein and chrome tanning agent as the result of chemical reactions between organic and inorganic parts with the new structure formation.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.10043

  4. TOPEM DSC study of glass transition region of polyurethane cationomers

    International Nuclear Information System (INIS)

    Pielichowska, Kinga; Król, Piotr; Król, Bożena; Pagacz, Joanna

    2012-01-01

    Highlights: ► TOPEM DSC method was employed to investigate the glass transition (T g ) region of fluorinated polyurethane cationomers. ► Introduction of fluorine compounds significantly changes thermal behaviour of cationomers in the T g region of hard segments. ► Introduction of fluorine compound leads to changes of the slope in activation diagram of glass transition. - Abstract: In this paper TOPEM DSC method was employed to investigate the glass transition region of fluorinated polyurethane cationomers. Fluorinated polyurethane cationomers have been synthesised in the reaction of MDI with poly(ethylene glycol) (600) and butane1,4-diol or N-methyl- or N-butyldiethanolamine and 2,2,3,3-tetrafluoro-1,4-butanediol. Better rigidity was found for generally amorphous cationomer coats. It was found that introduction of fluorine compound changes thermal behaviour of polyurethane cationomers as well as leads to changes in the slope in activation diagram profiles of glass transition in comparison to polyuretahene cationomer without fluorine compound. Application of TOPEM DSC allows to obtain more information concerning frequency dependence of glass transition region and thermodynamical stability of polyurethane structures.

  5. Waterborne Pathogens: Detection Methods and Challenges

    Directory of Open Access Journals (Sweden)

    Flor Yazmín Ramírez-Castillo

    2015-05-01

    Full Text Available Waterborne pathogens and related diseases are a major public health concern worldwide, not only by the morbidity and mortality that they cause, but by the high cost that represents their prevention and treatment. These diseases are directly related to environmental deterioration and pollution. Despite the continued efforts to maintain water safety, waterborne outbreaks are still reported globally. Proper assessment of pathogens on water and water quality monitoring are key factors for decision-making regarding water distribution systems’ infrastructure, the choice of best water treatment and prevention waterborne outbreaks. Powerful, sensitive and reproducible diagnostic tools are developed to monitor pathogen contamination in water and be able to detect not only cultivable pathogens but also to detect the occurrence of viable but non-culturable microorganisms as well as the presence of pathogens on biofilms. Quantitative microbial risk assessment (QMRA is a helpful tool to evaluate the scenarios for pathogen contamination that involve surveillance, detection methods, analysis and decision-making. This review aims to present a research outlook on waterborne outbreaks that have occurred in recent years. This review also focuses in the main molecular techniques for detection of waterborne pathogens and the use of QMRA approach to protect public health.

  6. Surveillance Systems for Waterborne Protozoa: Beyond Method 1623

    Science.gov (United States)

    1. Brief introduction to waterborne Cryptosporidium and Giardia Historical perspective on detecting Cryptosporidium and Giardia Current detection methodologies 2. US EPA’s waterborne protozoan research program Building a “Protoz...

  7. Surveillance Systems for Waterborne Protozoa Past, Present and Future

    Science.gov (United States)

    OVERVIEW I. Brief introduction to waterborne Cryptosporidium Historical perspective on detecting Cryptosporidium Current detection methodologies II. US EPA’s waterborne protozoan research program Detecting, typing, and tracking sources of Cryptosporidium contami...

  8. Developement of Spherical Polyurethane Beads

    Institute of Scientific and Technical Information of China (English)

    K. Maeda; H. Ohmori; H. Gyotoku

    2005-01-01

    @@ 1Results and Discussion We established a new method to produce the spherical polyurethane beads which have narrower distribution of particle size. This narrower distribution was achieved by the polyurethane prepolymer which contains ketimine as a blocked chain-extending agent. Firstly, the prepolymer is dispersed into the aqueous solution containing surfactant. Secondaly, water comes into the inside of prepolymer as oil phase. Thirdly, ketimine is hydrolyzed to amine, and amine reacts with prepolymer immediately to be polyurethane.Our spherical polyurethane beads are very suitable for automotive interior parts especially for instrument panel cover sheet producing under the slush molding method, because of good process ability, excellent durability to the sunlight and mechanical properties at low temperature. See Fig. 1 ,Fig. 2 and Fig. 3 (Page 820).

  9. Thermal behaviour properties and corrosion resistance of organoclay/polyurethane film

    Science.gov (United States)

    Kurniawan, O.; Soegijono, B.

    2018-03-01

    Organoclay/polyurethane film composite was prepared by adding organoclay with different content (1, 3, and 5 wt.%) in polyurethane as a matrix. TGA and DSC showed decomposition temperature shifted to a lower point as organoclay content change. FT-IR spectra showed chemical bonding of organoclay and polyurethane as a matrix, which means that the bonding between filler and matrix occured and the composite was stronger but less bonding occur in composite with 5 wt.% organoclay. The corrosion resistance overall increased with the increasing organoclay content. Composite with 5 wt.% organoclay had more thermal stability and corrosion resistance may probably due to exfoliation of organoclay.

  10. Facile approach to fabricate waterborne polyaniline nanocomposites with environmental benignity and high physical properties

    Science.gov (United States)

    Wang, Haihua; Wen, Huan; Hu, Bin; Fei, Guiqiang; Shen, Yiding; Sun, Liyu; Yang, Dong

    2017-03-01

    Waterborne polyaniline (PANI) dispersion has got extensive attention due to its environmental friendliness and good processability, whereas the storage stability and mechanical property have been the challenge for the waterborne PANI composites. Here we prepare for waterborne PANI dispersion through the chemical graft polymerisation of PANI into epichlorohydrin modified poly (vinyl alcohol) (EPVA). In comparison with waterborne PANI dispersion prepared through physical blend and in situ polymerisation, the storage stability of PANI-g-EPVA dispersion is greatly improved and the dispersion keeps stable for one year. In addition, the as-prepared PANI-g-EPVA film displays more uniform and smooth morphology, as well as enhanced phase compatibility. PANI is homogeneously distributed in the EPVA matrix on the nanoscale. PANI-g-EPVA displays different morphology at different aniline content. The electrical conductivity corresponds to 7.3 S/cm when only 30% PANI is incorporated into the composites, and then increases up to 20.83 S/cm with further increase in the aniline content. Simultaneously, the tensile strength increases from 35 MPa to 64 MPa. The as-prepared PANI-g-EPVA dispersion can be directly used as the conductive ink or coatings for cellulose fibre paper to prepare flexible conductive paper with high conductivity and mechanical property, which is also suitable for large scalable production.

  11. Synthesis and Characterization of Novel Polyurethanes Based on Vegetable Oils Amide and Ester Polyols

    Directory of Open Access Journals (Sweden)

    Vladimir YAKUSHIN

    2014-09-01

    Full Text Available Amide and ester type polyols were synthesized from rapeseed, sunflower and castor oils, and two types of ethanolamine (diethanolamine and triethanolamine at different molar ratio. Poly(urethane amides and polyester urethanes based on the synthesized polyols were prepared. The effect of the chemical structure of the obtained polyurethanes on density, glass transition temperature, thermal stability and mechanical properties was investigated. The influence of the content of OH groups in the synthesized polyols on the specified characteristics was estimated. It has been found that poly(urethane amides have better mechanical characteristics, but their thermal stability is lower than that of polyester urethanes. The chemical structure of the synthesized polyols and polyurethanes is qualitatively confirmed by IR-spectroscopy data. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4532

  12. The Modification of Polyurethane Foams Using New Boroorganic Polyols (II) Polyurethane Foams from Boron-Modified Hydroxypropyl Urea Derivatives

    Science.gov (United States)

    2014-01-01

    The work focuses on research related to determination of application possibility of new, ecofriendly boroorganic polyols in rigid polyurethane foams production. Polyols were obtained from hydroxypropyl urea derivatives esterified with boric acid and propylene carbonate. The influence of esterification type on properties of polyols and next on polyurethane foams properties was determined. Nitrogen and boron impacts on the foams' properties were discussed, for instance, on their physical, mechanical, and electric properties. Boron presence causes improvement of dimensional stability and thermal stability of polyurethane foams. They can be applied even at temperature 150°C. Unfortunately, introducing boron in polyurethanes foams affects deterioration of their water absorption, which increases as compared to the foams that do not contain boron. However, presence of both boron and nitrogen determines the decrease of the foams combustibility. Main impact on the decrease combustibility of the obtained foams has nitrogen presence, but in case of proper boron and nitrogen ratio their synergic activity on the combustibility decrease can be easily seen. PMID:24587721

  13. Mechanical and thermal properties of castor oil polyurethane bone cement after gamma irradiation

    International Nuclear Information System (INIS)

    Azevedo, E.C.; Chierice, G.O.; Claro Neto, S.; Lepiesnki, C.M.; Nascimento, E.M.

    2009-01-01

    Polyurethanes from castor oil are being employed as bone cement in medical applications. In this work the thermal and mechanical properties of gamma irradiated polyurethanes derivative from castor oil were investigated by instrumented indentation, thermogravimetry and scanning electron microscopy. A slightly increase in hardness is observed only for doses as high as 100 kGy. Thermal analysis indicates stability at human body temperature. The glass transition temperature has small changes after gamma irradiation. (author)

  14. Preparation and demonstration of poly(dopamine)-triggered attapulgite-anchored polyurethane as a high-performance rod-like elastomer to reinforce soy protein-isolated composites

    Science.gov (United States)

    Zhao, Shujun; Wen, Yingying; Wang, Zhong; Kang, Haijiao; Li, Jianzhang; Zhang, Shifeng; Ji, Yong

    2018-06-01

    Nanophase modification is an effective path to improve composite properties, however, it remains a great challenge to increase the mechanical strength of the modified materials without sacrificing elongation and toughness. This study presents a novel and efficient design for interface anchoring of a waterborne polyurethane (WPU) elastomer with attapulgite (ATP) triggered by poly(dopamine) (PDA) formation due to self-polymerization of the dopamine moieties. The WPU-PDA-ATP (WDA) rod-like elastomer served as an active enhancer for a soy protein isolate (SPI)-based composite to facilitate multiple interactions between SPI and the elastomer. As expected, the PDA layer was coated onto ATP, inducing the nanofiller to successfully anchor onto the WPU elastomer, as confirmed by solid-state 13C NMR, XPS, and ATR-FTIR results. Compared with the control SPI-based film, the tensile strength and toughness increased by 145.6% and 118.3% respectively by introducing WDA rod-like elastomer. The water resistance and thermal stability of the prepared SPI composites were also favorable. The proposed approach represents an efficient way to utilize high-performance elastomer in biobased materials to concurrently enhance strength and toughness.

  15. Selection of Hydrological Model for Waterborne Release

    International Nuclear Information System (INIS)

    Blanchard, A.

    1999-01-01

    This evaluation will aid in determining the potential impacts of liquid releases to downstream populations on the Savannah River. The purpose of this report is to evaluate the two available models and determine the appropriate model for use in following waterborne release analyses. Additionally, this report will document the Design Basis and Beyond Design Basis accidents to be used in the future study

  16. 40 CFR 721.8095 - Silylated polyurethane.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Silylated polyurethane. 721.8095... Substances § 721.8095 Silylated polyurethane. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a silylated polyurethane (PMN P-95-1356) is...

  17. 40 CFR 721.8090 - Polyurethane polymer.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyurethane polymer. 721.8090 Section... Substances § 721.8090 Polyurethane polymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (P-94-47) is subject...

  18. Biomaterial based novel polyurethane adhesives for wood to wood and metal to metal bonding

    Directory of Open Access Journals (Sweden)

    Mitesh Ramanlal Patel

    2009-01-01

    Full Text Available Polyurethane adhesives made from synthetic chemicals are non-biodegradable, costly and difficult to find raw materials from local market. To avoid solid pollution problem, cost effectiveness and easy availability of raw materials, biomaterials based polyurethane adhesives are used in current industrial interest. Direct use of castor oil in polyurethane adhesive gives limited hardness. Modification on active sites of castor oil to utilize double bond of unsaturated fatty acid and carboxyl group yields new modified or activated polyols, which can be utilized for polyurethane adhesive formulation. In view of this, we have synthesized polyurethane adhesives from polyester polyols, castor oil based polyols and epoxy based polyols with Isocyanate adducts based on castor oil and trimethylolpropane. To study the effects of polyurethane adhesive strength (i.e. lap shear strength on wood-to-wood and metal-to-metal bonding through various types of polyols, cross-linking density, isocyanate adducts and also to compare adhesive strength between wood to wood and metal to metal surface. These polyols and polyurethanes were characterized through GPC, NMR and IR-spectroscopy, gel and surface drying time. Thermal stability of PU adhesives was determined under the effect of cross-linking density (NCO/OH ratio. The NCO/OH ratio (1.5 was optimized for adhesives as the higher NCO/OH ratio (2.0 increasing cross-linking density and decreases adhesion. Lower NCO/OH ratio (1.0 provideslow cross-linking density and low strength of adhesives.

  19. Electrospun polyurethane membranes for Tissue Engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, Laís P., E-mail: lagabriel@gmail.com [National Institute of Biofabrication, Campinas (Brazil); Department of Chemical Engineering, University of Campinas, Campinas (Brazil); Rodrigues, Ana Amélia [National Institute of Biofabrication, Campinas (Brazil); Department of Medical Sciences, University of Campinas, Campinas (Brazil); Macedo, Milton; Jardini, André L.; Maciel Filho, Rubens [National Institute of Biofabrication, Campinas (Brazil); Department of Chemical Engineering, University of Campinas, Campinas (Brazil)

    2017-03-01

    Tissue Engineering proposes, among other things, tissue regeneration using scaffolds integrated with biological molecules, growth factors or cells for such regeneration. In this research, polyurethane membranes were prepared using the electrospinning technique in order to obtain membranes to be applied in Tissue Engineering, such as epithelial, drug delivery or cardiac applications. The influence of fibers on the structure and morphology of the membranes was studied using scanning electron microscopy (SEM), the structure was evaluated by Fourier transform infrared spectroscopy (FT-IR), and the thermal stability was analyzed by thermogravimetry analysis (TGA). In vitro cells attachment and proliferation was investigated by SEM, and in vitro cell viability was studied by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays and Live/Dead® assays. It was found that the membranes present an homogeneous morphology, high porosity, high surface area/volume ratio, it was also observed a random fiber network. The thermal analysis showed that the membrane degradation started at 254 °C. In vitro evaluation of fibroblasts cells showed that fibroblasts spread over the membrane surface after 24, 48 and 72 h of culture. This study supports the investigation of electrospun polyurethane membranes as biocompatible scaffolds for Tissue Engineering applications and provides some guidelines for improved biomaterials with desired properties.

  20. Castor Oil Based Polyurethanes: Synthesis and Characterization

    Science.gov (United States)

    Macalino, AD; Salen, VA; Reyes, LQ

    2017-09-01

    In this study, polyurethanes based on castor oil and 1,6-hexamethylene diisocyanate (HMDI) were synthesized with varying weight ratio of the castor oil and HMDI. The formation of urethane linkages was verified through the use of a fourier transform infrared spectroscopy (FTIR). The hydrophilicity of the films was evaluated through the use of a contact angle meter and it was found that the contact angle of all the films were below 90 degrees which confirms their hydrophilicity. The thermal stability of the PU films were studies through the use of a thermal gravimetric analyzer and found that all of the polyurethane films exhibited two weight loss events at elevated temperatures wherein the first weight loss event was observed to occur at 285°C to 384°C while the second weight loss event was observed at around 521°C to 551°C. The hardness, elastic modulus, and tensile elongation of the PU films were determined by using a universal testing machine (UTM) where it was found out that the hardness and the elastic modulus of the film is directly proportional with HMDI loading while the tensile elongation is inversely proportional to it. Lastly, it was known through the swelling studies of the PU films that it does not swell, this is due to the presence of unreacted triglycerides in the material, which prevents water from permeating to the films.

  1. Polyurethane Foams with Pyrimidine Rings

    Directory of Open Access Journals (Sweden)

    Kania Ewelina

    2014-09-01

    Full Text Available Oligoetherols based on pyrimidine ring were obtained upon reaction of barbituric acid with glycidol and alkylene carbonates. These oligoetherols were then used to obtain polyurethane foams in the reaction of oligoetherols with isocyanates and water. The protocol of foam synthesis was optimized by the choice of proper kind of oligoetherol and synthetic composition. The thermal resistance was studied by dynamic and static methods with concomitant monitoring of compressive strength. The polyurethane foams have similar physical properties as the classic ones except their enhanced thermal resistance. They stand long-time heating even at 200°C. Moreover thermal exposition of foams results generally in increase of their compressive strength.

  2. Polyurethane - positioning aids in radiotherapy

    International Nuclear Information System (INIS)

    Alzen, G.; Boeck, E.G.; Thelen, M.; Kutzner, J.

    1985-01-01

    A simple and cheap method is described for the manufacturing of individual positioning aids made of foamed polyurethane. Some examples are given to demonstrate the applicability of these positioning aids for the irradiation of different body regions. The reproducibility of the radiation field in the head and neck area was investigated with and without positioning aid. It was proved that the field is adjusted more exactly when positioning aids are applied. The dosimetric investigations performed showed a negligible influence of foamed polyurethane on the radiation quality. So the positioning aids could be left within the radiation field when drawing the field borders. (orig.) [de

  3. Bioactive polyurethane implants with hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Rozhnova, R.; Kebuladze, I.; Galatenko, N. [NAS Ukraine, Kiev (Ukraine). Dept. of Polymers of Medical Appointment

    2001-07-01

    Biologically active polyurethane compositions for plastic of bone defects that contain bioceramic - hydroxyapatite (HAP) and immunomodulator - levamisole (LEV) were designed. The influence of the biologically active fillers in structure polyurethane compositions on their physical and chemical properties in condition in vivo by method of Equilibrium Swelling, method of IR-spectroscopy, roentgen-structural analysis was studied. The introduce in structure of the biodegraded polymeric matrix of HAP is established to promote accumulation of the inorganic component of bone tissue in vivo which is being by basis of the bone formation in regenerating tissue. (orig.)

  4. Characterization of polyurethane based on polyol synthesized from glycerol and hexamethylene diisocyanate

    International Nuclear Information System (INIS)

    Carvalho, Sabrina M.; Weber, Vanessa; Silva, Tailu N.; Barreto, Pedro L.M.

    2009-01-01

    A new polyol based on glycerol was synthesized and used in the production of polyurethane by reaction with hexamethylene diisocyanate. The polyol was characterized by nuclear magnetic resonance spectroscopy (NMR) and Fourier transform-infrared spectroscopy (FTIR). The polyurethane produced was characterized by FTIR, thermogravimetry (TG), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The polyol was shown to be reactive with hexamethylene diisocyanate, as the FTIR spectrum showed no free isocyanate groups and identified the presence of group -C=O of urethane groups. Analysis by DSC showed that the sample of polyurethane has a glass transition temperature around -8.53 deg C and SEM micrographs showed fracture and surface continuous and not broken. The thermogravimetric analysis showed that the polyurethane produced has a high thermal stability with a temperature of maximum degradation around 430 deg C. (author)

  5. WATER-BORNE OIL-MODIFIED POLYURETHANE COATINGS VIA HYBRID MINIEMULSION POLYMERIZATION. (R825326)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  6. The waterborne polyurethane dispersions based on polycarbonate diol: effect of ionic content

    Czech Academy of Sciences Publication Activity Database

    Cakić, S. M.; Špírková, Milena; Ristić, I. S.; B-Simendić, J. K.; M-Cincović, M.; Poreba, Rafal

    2013-01-01

    Roč. 138, č. 1 (2013), s. 277-285 ISSN 0254-0584 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : coatings * chemical synthesis * thermogravimetric analysis (TGA) Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.129, year: 2013

  7. Additive Manufacturing of Polyurethane Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kunc, Vlastimil [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lindahl, John M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Minneci, Robert P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pyzik, Alek [Dow Chemical Company, Saginaw, MI (United States); Gorin, Craig [Dow Chemical Company, Midland, MI (United States); Allen, Sharon [Dow Chemical Company, Midland, MI (United States); Wilson, Keith [Dow Chemical Company, Midland, MI (United States); Howard, Kevin [Dow Chemical Company, Midland, MI (United States)

    2017-08-10

    ORNL worked with The DOW Chemical Company to validate the feasibility of 3D printing DOW’s polyurethane (PU) materials using ORNL’s equipment and know-how. This led to the development of the first directly-3D-printable PU material.

  8. Synthesis and Properties of Novel Polyurethane Containing Nitrophenylazocatecholic Group as NLO Chromophore

    International Nuclear Information System (INIS)

    Song, Mi Young; Kim, Mi Sung; Lee, Ju Yeon

    2012-01-01

    The promise of NLO polymers lies in their higher nonlinear optical activity, faster response time, and easy fabrication into electro-optic devices. In the developments of NLO polymers for electrooptic device applications, stabilization of electrically induced dipole alignment is one of important considerations; in this context, two approaches to minimize the randomization have been proposed, namely the use of cross-linked systems and the utilization of polymers with high glass transition temperature (T g ) such as polyimides. A polyurethane matrix forms extensive hydrogen bonding between urethane linkages, with increased rigidity preventing the relaxation of induced dipoles. Polyurethanes functionalized with hemicyanine and thiophene ring in side chain show an enhanced thermal stability of aligned dipoles. Polyurethanes with NLO chromophores, whose dipole moments are aligned transverse to the main chains, show large second-order nonlinearity with good thermal stability

  9. Development of bacterially resistant polyurethane for coating medical devices

    International Nuclear Information System (INIS)

    Roohpour, Nima; Moshaverinia, Alireza; Wasikiewicz, Jaroslaw M; Paul, Deepen; Vadgama, Pankaj; Wilks, Mark; Millar, Michael

    2012-01-01

    Polyurethanes have been widely used in medicine for coating and packaging implantable and other medical devices. Polyether-urethanes, in particular, have superior mechanical properties and are biocompatible, but in common with other medical materials they are susceptible to microbial film formation. In this study, polyether-urethane was end-capped with silver lactate and silver sulfadiazine functional groups to produce a bacterially resistant polymer without sacrificing the useful mechanical properties of the polyether-polyurethane. The silver ions were covalently incorporated into the polymer during chain extension of the prepolymer. The functionalized polymers were structurally characterized by light scattering, electron microscopy, NMR, FTIR and Raman spectroscopy. Mechanical properties, hydrophilicity, in vitro stability and antibacterial action of polymers were also investigated. Results indicate that both silver salts were successfully incorporated into the polymer structure without significant effect on mechanical properties, whilst conferring acceptable bacterial resistance.

  10. Synthesis and Properties of Some polyurethane/ Partially Aromatic Polyester Casting Samples

    International Nuclear Information System (INIS)

    Sadek, E.M.; Mazroua, A.M.; Emam, A.S.; Motawie, A.M.

    2005-01-01

    A series of partially aromatic terephthalate polyesters were synthesized by melt transesterification of dimethyl terephthalate with various types of aliphatic diol compounds in 1:1.1 molar ratio. Ethylene-, di-, tri-, tetra ethylene glycol and polyethylene glycol with different molecular weights 1000, 4000, 6000 as well as the prepared dihydroxy natural rubber were used. Another series of partially aromatic adipate and sebacate polyesters based on the prepared bisphenol A and its tetrabromo derivative were also synthesized by direct polycondensation esterification with adipic and sebacic acid. Polyurethane with NCO/OH ratio equal 4 was prepared from the reaction of 2,4 toluene diisocyanate with polyethylene glycol 1000. The prepared polyurethane was mixed with different weight percentages (2, 4, 6, 8, 10 or 12 % w/w) of the prepared partially aromatic polyesters to give polyurethane/polyester compositions. Mechanical and electrical properties as well as water and chemical resistance of the prepared film samples with thickness 3-4 mm were determined and compared with those of polyurethane film sample without polyester. The data indicate that 10 % w/w of the added partially aromatic polyester increases polyurethane tensile strength, improves its insulation properties and hydrolytic stability as well as its chemical resistance. Film samples based on bisphenol A impart excellent properties as compared with those based on aliphatic glycol species and dihydroxy natural rubber. Keywords: Partially aromatic polyesters, Dimethyl terephthalate, Glycols, Bisphenol A, Tetrabromo bisphenol A, Natural rubber, Adipic acid, Sebacic acid, Polyurethane, Casting

  11. Effects of Additives on Weather-Resistance Properties of Polyurethane Films Exposed to Ultraviolet Radiation and Ozone Atmosphere

    Directory of Open Access Journals (Sweden)

    Haiyan Wang

    2014-01-01

    Full Text Available Three polyurethane films were prepared by adding the antioxidant-1010 and the composite stabilizer to the polyurethane matrix, respectively. The accelerated weathering tests were performed by using self-designed UV/ozone aging test device. The color difference, yellowness index, UV-Vis spectrum, and infrared spectrum were recorded with colorimeter apparatus, UV-Vis spectroscopy, and FT-IR spectroscopy, respectively. The results show that, for the polyurethane film, the composite stabilizer can remarkably decrease UV transmission, the antioxidant-1010 and the composite stabilizer can markedly decrease the photooxidation index and the carbonyl index, respectively, and the antioxidant-1010 can significantly improve the antiyellowing properties after 60 h exposure. With incremental exposure time for the three films, UV-Vis transmission decreases, the photooxidation index, the carbonyl index, color difference, and yellowness index increase gradually. Under current experimental conditions, the order of UV/O3 aging resistance from highness to lowness is as follows: the polyurethane film modified by the antioxidant-1010, the polyurethane film modified by composite stabilizer, and the pure polyurethane film.

  12. Sustained Release Drug Delivery Applications of Polyurethanes

    Directory of Open Access Journals (Sweden)

    Michael B. Lowinger

    2018-05-01

    Full Text Available Since their introduction over 50 years ago, polyurethanes have been applied to nearly every industry. This review describes applications of polyurethanes to the development of modified release drug delivery. Although drug delivery research leveraging polyurethanes has been ongoing for decades, there has been renewed and substantial interest in the field in recent years. The chemistry of polyurethanes and the mechanisms of drug release from sustained release dosage forms are briefly reviewed. Studies to assess the impact of intrinsic drug properties on release from polyurethane-based formulations are considered. The impact of hydrophilic water swelling polyurethanes on drug diffusivity and release rate is discussed. The role of pore formers in modulating drug release rate is examined. Finally, the value of assessing mechanical properties of the dosage form and approaches taken in the literature are described.

  13. High molecular weight polyurethanes and a polyurethane urea based on 1,4-butanediisocyanate

    NARCIS (Netherlands)

    Spaans, CJ; de Groot, JH; Dekens, FG; Pennings, AJ

    New biomedical polyurethanes and a polyurethane urea based on epsilon-caprolactone and 1,4-butanediisocyanate have been developed. On degradation, only non-toxic products are produced. The polyurethane urea with poly(epsilon-caprolactone) soft segments and butanediisocyanate/butanediamine hard

  14. Sorption of heteropoly acids by polyurethane foam

    International Nuclear Information System (INIS)

    Dmitreinko, S.G.; Goncharova, L.V.; Runov, V.K.; Zakharov, V.N.; Aslanova, L.A.

    1997-01-01

    Sorption of oxidized and reduced forms of molybdosilicic, molybdophosphoric and molybdovanadophosphoric acids by polyurethane foam based on ethers and esters is studied. On the basis of sorption dependence on solution pH, polyurethane foam type and spectral characteristics of sorbates the suggestion has been made that in the polyurethane foam phase there are two main types of sorbent-sorbate interaction: electrostatic (ion-ion) and with hydrogen bond formation: and it is impossible to determine the contribution of every interaction

  15. Adhesion aspects of polyurethane foam sandwich panels.

    OpenAIRE

    Ng, Simon L.

    2016-01-01

    Sandwich panels, polyurethane foam sandwiched between two sheets of steel, form the walls and roofs in the construction of buildings. ArcelorMittal is a manufacturer of the steel as well as these finished panels. For this project they combined with a supplier of the polyurethane foams, Huntsman Polyurethanes, to joint-fund a research project investigating the fundamental mechanisms of adhesion, as well as the causes of failures in the product which manifests primarily in two different ways...

  16. Structure and Properties of Polyurethanes. Part 1,

    Science.gov (United States)

    1979-03-23

    since the solidification of varnish coatings on basis it is polyurethane usually it occurs under conditions for contact wita moisture of air. Page...containing fluorine is polyurethane. In works (44, 84-86] is given the information about synthesis 11 DOC = 79011105 PAGE and special feature/peculiarities...of the phase transformations of the series/number of the fluorine -bedrlng aliphatic ones it is polyurethane. Page 87. In particular, were investigated

  17. Attachment of inorganic moieties onto aliphatic polyurethanes

    Directory of Open Access Journals (Sweden)

    Eliane Ayres

    2007-06-01

    Full Text Available Polyurethanes have been used in a series of applications due basically to their versatility in terms of controlling the behavior by altering basically the type of reagents used. However, for more specific and advanced applications, such as in membranes, biomaterials and sensors, well-organized and defined chemical functionalities are necessary. In this work, inorganic functionalities were incorporated into aliphatic polyurethanes (PU having different macromolecular architectures. Polyurethanes were synthesized using a polyether diol and dicyclohexylmethane 4,4' diisocyanate (H12-MDI. Polyurethanes having carboxylic acid groups were also produced by introducing 2,2- bis (hydroxymethyl propionic acid in the polymerization process. Inorganic functionalities were inserted into polyurethanes by reacting isocyanate end capped chains with aminopropyltriethoxysilane followed by tetraethoxysilane. PU having carboxylic acid groups yielded transparent samples after the incorporation of inorganic entities, as an evidence of smaller and better dispersed inorganic entities in the polymer network. FTIR and swelling measurements showed that polyurethanes having carboxylic acid groups had inorganic domains less packed, condensed and cross-linked when compared to polyurethanes with no carboxylic acid groups. Results also suggested that the progressive incorporation of inorganic moieties in both types of polyurethanes occurred in regions previously activated with inorganic functionalities, instead of by the creation of new domains. The temperatures of thermal decomposition and glass transition were also shifted to higher temperatures when inorganic functionalities were incorporated into polyurethanes.

  18. Selection of Hydrological Model for Waterborne Release

    International Nuclear Information System (INIS)

    Blanchard, A.

    1999-01-01

    Following a request from the States of South Carolina and Georgia, downstream radiological consequences from postulated accidental aqueous releases at the three Savannah River Site nonreactor nuclear facilities will be examined. This evaluation will aid in determining the potential impacts of liquid releases to downstream populations on the Savannah River. The purpose of this report is to evaluate the two available models and determine the appropriate model for use in following waterborne release analyses. Additionally, this report will document the accidents to be used in the future study

  19. Giardiasis: a return of waterborne disease

    Energy Technology Data Exchange (ETDEWEB)

    Spofford, W.O. Jr.

    Complacency about safe water supply has turned to concern over possible chemical contamination and waterborne disease, giardiasis, caused by a protozoan. A case study of an outbreak of giardiasis in Pennsylvania raises questions about water treatment strategies, which must necessarily vary because of differences in public water systems. While giardiasis is an unpleasant and uncomfortable disease, it is not as serious as typhoid, dysentery, and other diseases. The costs of analyzing water systems to detect and eliminate the risk of contamination may exceed the costs of the disease itself. Americans have grown used to safe drinking water, however, and may conclude that the benefits are worth the cost. 2 figures, 1 table.

  20. Vegetable Oil-Based Hyperbranched Thermosetting Polyurethane/Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Deka Harekrishna

    2009-01-01

    Full Text Available Abstract The highly branched polyurethanes and vegetable oil-based polymer nanocomposites have been showing fruitful advantages across a spectrum of potential field of applications.Mesua ferreaL. seed oil-based hyperbranched polyurethane (HBPU/clay nanocomposites were prepared at different dose levels by in situ polymerization technique. The performances of epoxy-cured thermosetting nanocomposites are reported for the first time. The partially exfoliated structure of clay layers was confirmed by XRD and TEM. FTIR spectra indicate the presence of H bonding between nanoclay and the polymer matrix. The present investigation outlines the significant improvement of tensile strength, scratch hardness, thermostability, water vapor permeability, and adhesive strength without much influencing impact resistance, bending, and elongation at break of the nanocomposites compared to pristine HBPU thermoset. An increment of two times the tensile strength, 6 °C of melting point, and 111 °C of thermo-stability were achieved by the formation of nanocomposites. An excellent shape recovery of about 96–99% was observed for the nanocomposites. Thus, the formation of partially exfoliated clay/vegetable oil-based hyperbranched polyurethane nanocomposites significantly improved the performance.

  1. Vegetable Oil-Based Hyperbranched Thermosetting Polyurethane/Clay Nanocomposites.

    Science.gov (United States)

    Deka, Harekrishna; Karak, Niranjan

    2009-04-25

    The highly branched polyurethanes and vegetable oil-based polymer nanocomposites have been showing fruitful advantages across a spectrum of potential field of applications. Mesua ferrea L. seed oil-based hyperbranched polyurethane (HBPU)/clay nanocomposites were prepared at different dose levels by in situ polymerization technique. The performances of epoxy-cured thermosetting nanocomposites are reported for the first time. The partially exfoliated structure of clay layers was confirmed by XRD and TEM. FTIR spectra indicate the presence of H bonding between nanoclay and the polymer matrix. The present investigation outlines the significant improvement of tensile strength, scratch hardness, thermostability, water vapor permeability, and adhesive strength without much influencing impact resistance, bending, and elongation at break of the nanocomposites compared to pristine HBPU thermoset. An increment of two times the tensile strength, 6 degrees C of melting point, and 111 degrees C of thermo-stability were achieved by the formation of nanocomposites. An excellent shape recovery of about 96-99% was observed for the nanocomposites. Thus, the formation of partially exfoliated clay/vegetable oil-based hyperbranched polyurethane nanocomposites significantly improved the performance.

  2. COLOR STABILITY FOR WOOD PRODUCTS DURING USE: EFFECTS OF INORGANIC NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    Vincent Blanchard

    2011-04-01

    Full Text Available Despite significant progress having been achieved in recent years to improve wood’s durability, additional developments are still necessary to increase its color stability. ZnO and CeO2 nanoparticles were compared to UV absorbers (Tinuvin 477 DW, 292 and 5151 commonly used to stabilize the wood products color. Nanoparticles, with concentrations in the range 1 to 2 wt%, and UV absorbers, using concentrations advised by the manufacturer, were dispersed in a waterborne UV curable polyurethane/polyacrylate resin. Dispersions were carried out with a high speed mixer at 2,500 RPM with micro glass beads or not, depending on the form of the nanoparticles. Nanocomposite coatings were aged with a weather-o-meter (CI 3000+ - Atlas according ASTM G155. Color variations were measured with a colorimeter (BYK Gardner – Color Guide 45/0 working with the CIE L*a*b* system. The aim of the present study was to assess the effects of inorganic UV absorbers on the stabilization of color under indoor conditions. Results showed that nanoparticles (ZnO, CeO2 absorbed UV light frequencies in a manner similar to common organic molecules. Their efficiency was better at medium durations of light exposure, for which they could achieve the action of organic absorbers. Finally, the simultaneous use of both absorbers seems to create a protective synergy when degradation is due to UV energy alone.

  3. Formulation, Preparation, and Characterization of Polyurethane Foams

    Science.gov (United States)

    Pinto, Moises L.

    2010-01-01

    Preparation of laboratory-scale polyurethane foams is described with formulations that are easy to implement in experiments for undergraduate students. Particular attention is given to formulation aspects that are based on the main chemical reactions occurring in polyurethane production. This allows students to develop alternative formulations to…

  4. Polyurethane doped with low-concentration erbium

    NARCIS (Netherlands)

    Ciobanu, C.; Stoica, E.; Cascaval, C.N.; Rosu, D.; Rosu, L.; State, M.; Emandi, A.; Nemes, I.; Petrescu, F.

    2007-01-01

    ABSTRACT: Polyurethane (PU) with lactate structures inits conformation can be used as a biological and biodegradablepolymer. Polyurethane lactate (PUL) was dopedwith small quantities of an erbium (Er3þ) complex, whichhindered the N¼N group. 2,20-Dihydroxyazobenzene wasused as a ligand for the Er3þ

  5. A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles

    Directory of Open Access Journals (Sweden)

    Cheng K

    2017-03-01

    Full Text Available Kuo-Wei Cheng, Shan-hui Hsu Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, Taipei, Taiwan, Republic of China Abstract: Superparamagnetic iron oxide nanoparticles (SPIO NPs have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm suspended in water. SPIO-PU hybrid NPs contained ~50–60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3] or (9-(methylaminomethylanthracene [MAMA] could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95% without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers. Keywords: superparamagnetic iron oxide, polyurethane, drug release, hybrid nanoparticles

  6. Thermal properties of a sandwich construction insulated with Polyurethane (DC-System)

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Dreau, Jerome Le

    Rigid polyurethane foam (PUR) is a good thermal insulation product for buildings, mainly due to its low thermal conductivity (λ ≈ 20 mW/m.K), low permeability to water and stability over time. The other types of insulation products available on the market have a significantly higher thermal...... conductivity: + 50% for expanded polystyrene (λ ≈ 30 mW/m.K), + 75% for mineral wools (λ ≈ 35 mW/m.K), etc. Despite its low thermal conductivity, polyurethane foam (PUR) is not much used as insulation material for walls because of its low resistance to fire. The most common PUR boards are classified C-s2-d0...

  7. Polyurethane membranes for surgical gown applications

    Science.gov (United States)

    Ukpabi, Pauline Ozoemena

    The Occupational Safety and Health Administration (OSHA) recently issued a directive requiring all employers to supply personnel protective equipment to employees who are at risk of exposure to blood or other potentially infectious body fluids. For the healthcare worker, a wide variety of surgical gowns is available commercially but there are concerns over their barrier effectiveness and/or wearer comfort. To successfully create a barrier fabric which combines resistance to fluid penetration with comfort, a complete understanding of the relationship between membrane structure and functional properties is required. In this study, we investigated the surface properties of hydrophilicity and hydrophobicity in polyurethane membranes intended for use in surgical gowns. The polyurethane membranes were grafted with side chains of varying lengths, polyethylene glycol (PEG) being used for the hydrophilic modifications and perfluoroalkyl compounds (a monofunctional acid and a difunctional amino alcohol) for the hydrophobic modifications. The hydrophilic treatment was intended to improve the comfort properties of monolithic membranes without adversely affecting their barrier properties. The hydrophobic treatment, on the other hand, was intended to improve the fluid repellency and hence barrier properties of microporous membranes without adversely affecting their comfort properties. Reflection infrared spectroscopy showed that fluorine was successfully grafted onto the polyurethane backbone during the hydrophobic modification, but was not sensitive enough to detect PEG grafting in leached polyethylene glycol-treated polyurethanes. X-ray photoelectron spectroscopy showed that the perfluoroalkylated polyurethanes contained up to 40% fluorine on their surfaces and the PEG-treated polyurethanes showed an increase in their C-O content over the unmodified polyurethane. Scanning electron microscopy not only showed that perfluoroalkylation yielded polyurethane membranes with very

  8. Polyurethane nanofibers containing copper nanoparticles as future materials

    DEFF Research Database (Denmark)

    Sheikh, Faheem A.; Kanjwal, Muzafar Ahmed; Saran, Saurabh

    2011-01-01

    nanofibers. Typically, a colloidal gel consisting of copper NPs and polyurethane has been electrospun. SEM-EDX and TEM results confirmed well oriented nanofibers and good dispersion of pure copper NPs. Copper NPs have diameter in the range of 5–10nm. The thermal stability of the synthesized nanofibers...... the antimicrobial efficacy of these nanofiber mats. Subsequently, antimicrobial tests have indicated that the prepared nanofibers do posses good bactericidal effect. Accordingly, it is noted that the obtained nanofiber mats can be used as future filter membranes with good antimicrobial activities....

  9. Castor oil and commercial thermoplastic polyurethane membranes modified with polyaniline: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Almeida Junior, Jose Humberto Santos; Meneguzzi, Alvaro; Ferreira, Carlos Arthur, E-mail: jhsajunior@globomail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegtre, RS (Brazil). Dept. de Engenharia de Materiais; Bertuol, Daniel Assumpcao [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Dept. de Engenharia Quimica; Amado, Franco Dani Rico [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologia

    2013-11-01

    The study of conducting polymeric membranes is decisive in some areas, as in fuel cells and electrodialysis. This work aims the study of membranes using conventional and conductive polymers blends. Two types of polyurethane were used as conventional polymers, commercial thermoplastic polyurethane and polyurethane synthesized from castor oil and 4-4-dicyclohexylmethane isocyanate. Two kinds of conducting polymers were used, polyaniline doped with organic acid and a self doped polyaniline. The polymers and the membranes were characterized by electrical conductivity, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The synthesis of the membranes produced was proper, featuring a complete reaction, analyzed by FTIR. The membranes also showed good mechanical properties and thermal stability ( Almost-Equal-To 220 Degree-Sign C). Among the membranes studied, the polyaniline doped with p-toluenesulphonic acid obtained higher thermal and viscoelastic properties. Thus they can be used in separation techniques using membranes. (author)

  10. Impact of climate change on waterborne diseases

    Directory of Open Access Journals (Sweden)

    Enzo Funari

    2012-12-01

    Full Text Available Change in climate and water cycle will challenge water availability but it will also increase the exposure to unsafe water. Floods, droughts, heavy storms, changes in rain pattern, increase of temperature and sea level, they all show an increasing trend worldwide and will affect biological, physical and chemical components of water through different paths thus enhancing the risk of waterborne diseases. This paper is intended, through reviewing the available literature, to highlight environmental changes and critical situations caused by floods, drought and warmer temperature that will lead to an increase of exposure to water related pathogens, chemical hazards and cyanotoxins. The final aim is provide knowledge-based elements for more focused adaptation measures.

  11. Neutron gauging to detect voids in polyurethane

    International Nuclear Information System (INIS)

    Tsang, F.Y.; Alger, D.M.; Brugger, R.M.

    1978-01-01

    Thermal-neutron radiography and fast-neutron gauging measurements were made to evaluate the feasibility of detecting voids in a polyurethane block placed between steel plates. This sandwich of polyurethane and steel simulates the walls of a canister being designed to hold explosive devices. The polyurethane would act as a shock absorber in the canister. A large fabrication cost saving would result by casting the polyurethane, but a nondestructive testing (NDT) method is needed to determine the uniformity of the polyurethane fill. The radiography measurements used a beam of thermal neutrons, while the gauging used filtered beams of 24 keV and fission spectrum neutrons. For the 83-mm-thick polyurethane and 130-mm-thick steel matrix, the thermal-neutron radiography was able to detect only those voids equal to about one-half the polyurethane thickness. The gauging detected voids in the path of the neutron beam of a few millimetres thickness in seconds to minutes. The gauging is feasible as an NDT method for the canister application

  12. Bitumen modified with recycled polyurethane foam for employment in hot mix asphalt

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Salas

    2018-01-01

    Full Text Available A wide variety of modifiers have been applied to bitumen in order to enhance their properties and performance. Among them, polymers have been mainly used. The aim of this paper is to assess the use of polyurethane foam waste as a bitumen modifier for hot mix asphalts. The polyurethane foam is a by-product of the manufacturing of polyurethane for thermal insulation. From a bitumen with a penetration grade of 50/70, various samples with percentages of waste material in weight ranging from 1% to 5% were produced and tested. Samples with 5% of waste material or more became rough and were refused due to their poor workability. A bituminous mixture with modified bitumen with a 4% of polyurethane was manufactured and compared with a sample with the same aggregates and original bitumen. Results in Marshall test showed that a mix with polymer modified bitumen yielded improvements in stability and a lower deformability. This result suggests that the employment of polyurethane foam waste is a promising bitumen modifier, contributing also to recycle waste materials.

  13. Fabrication of superhydrophobic polyurethane/organoclay nano-structured composites from cyclomethicone-in-water emulsions

    International Nuclear Information System (INIS)

    Bayer, I.S.; Steele, A.; Martorana, P.J.; Loth, E.

    2010-01-01

    Nano-structured polyurethane/organoclay composite films were fabricated by dispersing moisture-curable polyurethanes and fatty amine/amino-silane surface modified montmorillonite clay (organoclay) in cyclomethicone-in-water emulsions. Cyclomethicone Pickering emulsions were made by emulsifying decamethylcyclopentasiloxane (D 5 ), dodecamethylcyclohexasiloxane (D 6 ) and aminofunctional siloxane polymers with water using montmorillonite particles as emulsion stabilizers. Polyurethane and organoclay dispersed emulsions were spray coated on aluminum surfaces. Upon thermosetting, water repellent self-cleaning coatings were obtained with measured static water contact angles exceeding 155 o and low contact angle hysteresis ( o ). Electron microscopy images of the coating surfaces revealed formation of self-similar hierarchical micro- and nano-scale surface structures. The surface morphology and the coating adhesion strength to aluminum substrates were found to be sensitive to the relative amounts of dispersed polyurethane and organoclay in the emulsions. The degree of superhydrophobicity was analyzed using static water contact angles as well as contact angle hysteresis measurements. Due to biocompatibility of cyclomethicones and polyurethane, developed coatings can be considered for specific bio-medical applications.

  14. Fabrication of superhydrophobic polyurethane/organoclay nano-structured composites from cyclomethicone-in-water emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Bayer, I.S., E-mail: ibayer1@illinois.edu [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Steele, A.; Martorana, P.J. [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Loth, E. [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Department of Mechanical and Aerospace Engineering, University of Virginia, VA 22904 (United States)

    2010-11-15

    Nano-structured polyurethane/organoclay composite films were fabricated by dispersing moisture-curable polyurethanes and fatty amine/amino-silane surface modified montmorillonite clay (organoclay) in cyclomethicone-in-water emulsions. Cyclomethicone Pickering emulsions were made by emulsifying decamethylcyclopentasiloxane (D{sub 5}), dodecamethylcyclohexasiloxane (D{sub 6}) and aminofunctional siloxane polymers with water using montmorillonite particles as emulsion stabilizers. Polyurethane and organoclay dispersed emulsions were spray coated on aluminum surfaces. Upon thermosetting, water repellent self-cleaning coatings were obtained with measured static water contact angles exceeding 155{sup o} and low contact angle hysteresis (<8{sup o}). Electron microscopy images of the coating surfaces revealed formation of self-similar hierarchical micro- and nano-scale surface structures. The surface morphology and the coating adhesion strength to aluminum substrates were found to be sensitive to the relative amounts of dispersed polyurethane and organoclay in the emulsions. The degree of superhydrophobicity was analyzed using static water contact angles as well as contact angle hysteresis measurements. Due to biocompatibility of cyclomethicones and polyurethane, developed coatings can be considered for specific bio-medical applications.

  15. Preparation and Characterization of Liquid Crystalline Polyurethane/Al2O3/Epoxy Resin Composites for Electronic Packaging

    Directory of Open Access Journals (Sweden)

    Shaorong Lu

    2012-01-01

    Full Text Available Liquid crystalline polyurethane (LCPU/Al2O3/epoxy resin composites were prepared by using LCPU as modifier. The mechanical properties, thermal stability, and electrical properties of the LCPU/Al2O3/epoxy resin composites were investigated systematically. The thermal oxidation analysis indicated that LCPU/Al2O3/epoxy resin composites can sustain higher thermal decomposition temperature. Meanwhile, coefficient of thermal expansion (CTE was also found to decrease with addition of LCPU and nano-Al2O3.

  16. Characterization of polyurethane/organophilic montmorillonite nanocomposites by low field NMR

    International Nuclear Information System (INIS)

    Silva, Marcos Anacleto da; Tavares, Maria I.B.; Nascimento, Suelen A.M.; Rodrigues, Elton J. da R

    2012-01-01

    Polyurethanes are important and versatile materials, mainly due to some of their properties, such as high resistance to abrasion and tearing, excellent absorption of mechanical shocks and good flexibility and elasticity. However, they have some drawbacks as well, such as low thermal stability and barrier properties. To overcome these disadvantages, various studies have been conducted involving organophilic polyurethane/montmorillonite nanocomposites. The investigation of the structure of polyurethane/clay nanocomposites has mainly been done by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this work, PU/clay nanocomposite films obtained by solution intercalation were studied. The nanocomposites were characterized by XRD and low-field nuclear magnetic resonance (LF-NMR). The LF-NMR measurements, with determination of the spin-lattice relaxation time of the hydrogen nucleus, supplied important information about the molecular dynamics of these nanocomposites. The X-ray diffraction measurements validated the results found by NMR. The thermal stability of the material was also determined by thermogravimetric analysis (TGA) under an inert atmosphere. A slight improvement in this stability was observed in the nanocomposite in comparison with polyurethane (author)

  17. Isothermal recovery rates in shape memory polyurethanes

    International Nuclear Information System (INIS)

    Azra, Charly; Plummer, Christopher J G; Månson, Jan-Anders E

    2011-01-01

    This work compares the time dependence of isothermal shape recovery in thermoset and thermoplastic shape memory polyurethanes (SMPUs) with comparable glass transition temperatures. In each case, tensile tests have been used to quantify the influence of various thermo-mechanical programming parameters (deformation temperature, recovery temperature, and stress and storage times following the deformation step) on strain recovery under zero load (free recovery) and stress recovery under fixed strain (constrained recovery). It is shown that the duration of the recovery event may be tuned over several decades of time with an appropriate choice of programming parameters, but that there is a trade-off between the rate of shape recovery and the recoverable stress level. The results are discussed in terms of the thermal characteristics of the SMPUs in the corresponding temperature range as characterized by modulated differential scanning calorimetry and dynamic mechanical analysis, with the emphasis on the role of the effective width of the glass transition temperature and the stability of the network that gives rise to the shape memory effect. (fast track communication)

  18. Dipodal Silane-modified Nano Fe3O4/Polyurethane Magnetic Nanocomposites: Preparation and Characterization

    Directory of Open Access Journals (Sweden)

    Mir Mohammad Alavi Nikje

    2016-01-01

    Full Text Available Magnetic nanocomposites were prepared by incorporation of pure Fe3O4 and surface-modified Fe3O4 nanoparticles (dipodal silane-modified Fe3O4 into a polyurethane elastomer matrix by in situ polymerization method. In preparation of these magnetic nanocomposites, polycaprolactone (PCL was used as a polyester polyol. Because of dipole-dipole interactions between nanoparticles and a large surface area to volume ratio, the magnetic iron oxide nanoparticles tended to agglomerate. Furthermore, the most important challenge was to coat the surface of magnetic Fe3O4 nanoparticles in order to prepare well dispersed and stabilized Fe3O4 magnetic nanoparticles. It was observed that surface modification of Fe3O4 nanoparticles enhanced the dispersion of the nanoparticles in polyurethane matrices and allowed magnetic nanocomposites to be prepared with better properties. Surface modification of Fe3O4 was performed by dipodal silane synthesized based on 3-aminopropyltriethoxysilane (APTS and γ-glycidoxypropyl trimethoxysilane (GPTS. Dipodal silane-coated magnetic nanoparticles (DScMNPs were synthesized and incorporated into the polyurethane elastomer matrix as reinforcing agents. The formation of dipodal silane was investigated by Fourier transform infrared spectroscopy (FTIR, proton nuclear magnetic resonance spectroscopy (1H NMR and transmission electron microscopy (TEM. Characterization and study on the magnetic polyurethane elastomer nanocomposites were performed by FTIR, thermogravimetric analysis (TGA, scanning electron microscopy (SEM, vibrating sample magnetometry (VSM and dynamic mechanical thermal analysis (DMTA. The VSM results showed that the synthesized polyurethane elastomer nanocomposites had a superparamagnetic behavior. The TGA results showed that the thermal stability of dipodal silane-modified Fe3O4/PU nanocomposite was higher than that of Fe3O4/PU nanocomposite. This could be attributed to better dispersion and compatibility of dipodal silane

  19. Association of water-borne diseases morbidity pattern and water ...

    African Journals Online (AJOL)

    1Department of Env ronmental Management and Tox cology, Un vers ty of Agr culture, PMB 2240,. Abeokuta, Ogun .... and a modern sector) that has implications for ... plastered with cement. ..... residents are at–risk of water-borne diseases.

  20. Conference Report: The 6th International Symposium on Waterborne Pathogens

    Data.gov (United States)

    U.S. Environmental Protection Agency — A review of current literature on the occurrence of waterborne pathogens in DW systems. This dataset is not publicly accessible because: I am using published data...

  1. Minimizing corrosive action in timber bridges treated with waterborne preservatives

    Science.gov (United States)

    Samuel L. Zelinka; Douglas R. Rammer; James P. Wacker

    2007-01-01

    This work will briefly review published literature and current research activities on the corrosion of metals in contact with wood treated with waterborne alternatives to CCA. In addition, recommendations to minimize these corrosive effects in timber bridges will be discussed.

  2. Is Waterborne Disease Still an Issue in the US?

    Centers for Disease Control (CDC) Podcasts

    In this podcast, CDC’s Dr. Michael Beach discusses the changing face of waterborne disease in the US over the past century and how healthcare providers can apply this information to their patients.

  3. Flame Retardants Used in Flexible Polyurethane Foam

    Science.gov (United States)

    The partnership project on flame retardants in furniture seeks to update the health and environmental profiles of flame-retardant chemicals that meet fire safety standards for upholstered consumer products with polyurethane foam

  4. 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.

  5. Intrinsically radiopaque polyurethanes with chain extender 4,4'-isopropylidenebis [2-(2,6-diiodophenoxy)ethanol] for biomedical applications.

    Science.gov (United States)

    Dawlee, S; Jayabalan, M

    2015-05-01

    Radiopaque polyurethanes are used for medical applications as it allows post-operative assessment of the biomaterial devices using X-ray. Inherently, radiopaque polyurethanes based on polytetramethylene glycol (PTMG), polypropylene glycol, 4,4'-methylenebis(phenyl isocyanate), and a new iodinated chain extender 4,4'-isopropylidenebis[2-(2,6-diiodophenoxy)ethanol] with flexible spacers were synthesized and characterized. The iodinated polyurethanes were clear, optically transparent, and had high molecular weights. The polyurethanes also possessed excellent radiopacity and high thermal stability. The biocompatibility of the most promising iodinated polyurethane was evaluated both in vitro (cytotoxicity evaluation by direct contact and MTT assay, using L929 mouse fibroblast cells) and in vivo (toxicology studies in rabbits and subcutaneous implantation in rats). The material was nontoxic and well tolerated by the animals. Thus, these radiopaque and transparent polyurethanes are expected to have potential for various biomedical applications. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  6. POLYURETHANE COMPOSITES AS DRUG CARRIERS:: RELEASE PATTERNS

    Directory of Open Access Journals (Sweden)

    M. V. Grigoreva

    2013-10-01

    Full Text Available Biodegradable polyurethanes attract interest of those developing composite materials for biomedical applications. One of their features is their ability to serve as carriers, or matrixes, for medicines and other bioactive compounds to produce a therapeutic effect in body through targeted and/or prolonged delivery of these compounds in the process of their controlled release from matrix. The review presents polyurethane composites as matrices for a number of drugs. The relation between structure of the composites and their degradability both in vitro and in vivo and the dependence of drug release kinetics on physicochemical properties of polyurethane matrix are highlighted. The release of drugs (cefazolin, naltrexone and piroxicam from the composites based on cross-linked polyurethanes (synthesized from laprols, Mw between 1,500 and 2,000 Da and toluylene diisocyanate demonstrated more or less the same pattern (about 10 days in vitro and three to five days in vivo. In contrast, the composites with dioxydine based on a linear polyurethanes (synthesized from oligotetramethilene glycol, Mw 1,000 Da, diphenylmethane-4,4’-diisocyanate and 1,4-butanediol retained their antimicrobial activity at least 30 days. They also showed a significantly higher breaking strength as compared to that of the composites based on cross-linked polyurethanes.

  7. Polycarbonate-based polyurethane as a polymer electrolyte matrix for all-solid-state lithium batteries

    Science.gov (United States)

    Bao, Junjie; Shi, Gaojian; Tao, Can; Wang, Chao; Zhu, Chen; Cheng, Liang; Qian, Gang; Chen, Chunhua

    2018-06-01

    Four kinds of polycarbonate-based polyurethane with 8-14 wt% hard segments content are synthesized via reactions of polycarbonatediol, hexamethylene diisocyanate and diethylene glycol. The mechanical strength of the polyurethanes increase with the increase of hard segments content. Solid polymer electrolytes composed of the polycarbonate-based polyurethanes and LiTFSI exhibits fascinating characteristics for all-solid-state lithium batteries with a high ionic conductivity of 1.12 × 10-4 S cm-1 at 80 °C, an electrochemical stability window up to 4.5 V (vs. Li+/Li), excellent mechanical strength and superior interfacial stability against lithium metal. The all-solid-state batteries using LiFePO4 cathode can deliver high discharge capacities (161, 158, 134 and 93 mAh g-1 at varied rates of 0.2, 0.5, 1 and 2 C) at 80 °C and excellent cycling performance (with 91% capacity retention after 600 cycles at 1 C). All the results indicate that such a polyurethane-based solid polymer electrolyte can be a promising candidate for all-solid-state lithium batteries.

  8. Use of Novel Polyurethane Microspheres in a Curcumin Delivery System

    Directory of Open Access Journals (Sweden)

    Yongmei Hu

    2014-01-01

    Full Text Available Despite having a wide range of beneficial pharmacological effects, curcumin is characterized by poor water solubility and absorption. In this study, novel polyurethane microspheres containing curcumin (Cur-PUMs were prepared using carboxymethyl cellulose sodium to improve the bioavailability and prolong the retention time of curcumin. The prepared Cur-PUMs were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, and ultraviolet spectrophotometer. The sustained-release effects of Cur-PUMs were demonstrated using stability tests in vitro and in vivo pharmacokinetic studies following oral administration. We found that the stability of Cur-PUMs was strongly affected by pH variation. Further, compared with free curcumin, Cur-PUMs showed significantly improved maximum concentration and half-life.

  9. Modeling Manufacturing Impacts on Aging and Reliability of Polyurethane Foams

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R.; Roberts, Christine Cardinal; Mondy, Lisa Ann; Soehnel, Melissa Marie; Johnson, Kyle; Lorenzo, Henry T.

    2016-10-01

    Polyurethane is a complex multiphase material that evolves from a viscous liquid to a system of percolating bubbles, which are created via a CO2 generating reaction. The continuous phase polymerizes to a solid during the foaming process generating heat. Foams introduced into a mold increase their volume up to tenfold, and the dynamics of the expansion process may lead to voids and will produce gradients in density and degree of polymerization. These inhomogeneities can lead to structural stability issues upon aging. For instance, structural components in weapon systems have been shown to change shape as they age depending on their molding history, which can threaten critical tolerances. The purpose of this project is to develop a Cradle-to-Grave multiphysics model, which allows us to predict the material properties of foam from its birth through aging in the stockpile, where its dimensional stability is important.

  10. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  11. 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...

  12. 40 CFR 721.9959 - Polyurethane polymer (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyurethane polymer (generic). 721... Substances § 721.9959 Polyurethane polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (PMN P-01...

  13. UV-curable polyurethane coatings derived from cellulose

    International Nuclear Information System (INIS)

    Patel, M. M.; Patel, K. I.; Patel, H. B.; Parmar, J. S.

    2009-01-01

    At the present time coating industry is devoting much research in the direction of low volatile organic compounds to make eco-friendly coating material. In this study, such materials are developed from cellulose derived from bagasse, a sugar industry waste. Cellulose is converted to cellulose glyco glycoside by acid hydrolysis of cellulose under heterogeneous condition. Cellulose glyco glycoside is treated with polyethylene glycol having different molecular weights to give glyco glycosides which in turn are reacted with various diisocyanates to obtain polyurethane having free NCO groups. These materials are then reacted with hydroxyethylmethacrylate to give polyurethane acrylates. The acrylates are characterized for specific gravity, viscosity, colour and molecular weight as well as by fourier transform infrared spectroscopy. The UV-curable coating composition was prepared by blending PU-acrylate, reactive diluents and photoinitiator. Coating compositions were cured under UV-light and characterized for adhesion, flexibility, impact resistance, solvent resistance and for dynamic mechanical analysis as well as by thermal gravimetric analysis for thermal stability. The cured films give thickness of 23-24 microns and cure time required is less than 1.5-2.0 min. There is no liberation of any volatiles during curing and films have good adhesion to mild steel substrate. The cured coatings give excellent dynamic, mechanical and chemical properties. The scratch resistance was found to be satisfactory. The application was made in unpigmented form but it is found that various pigments can be used to give coloured UV-curable coatings.

  14. [Waterborne diseases outbreaks in the Czech Republic, 1995-2005].

    Science.gov (United States)

    Kozísek, F; Jeligová, H; Dvoráková, A

    2009-08-01

    Despite considerable advances in drinking water safety assurance and adherence to the public health standards, waterborne diaseases outbreaks have still been observed even in industrialized countries. The study objective was to map such outbreaks in the Czech Republic in 1995-2005. In this study, an outbreak is the occurrence of more cases of disease than normally expected within a specific place over a given period of time and a waterborne disease is a disease where water is the vehicle or source of infection. The data on waterborne outbreaks was obtained from the EPIDAT database (national infectious diseases reporting system) information provided by epidemiologists of all regional public health authorities and the National Reference Laboratory for Legionella. In 1995 - 2005, 33 outbreaks with water indicated as the route of transmission were recorded in the Czech Republic. The leading cause was unsafe drinking water (27 outbreaks), mainly from wells (19 outbreaks); nevertheless, the most serious consequences were observed in two outbreaks caused by microbiologically contaminated hot water. Other sources of waterborne infection were mineral water springs, a swimming pool and a brook. The total of reported cases of waterborne diseases was 1655, 356 hospitalisations and ten deaths due to legionellosis were recorded. The highest number of outbreaks (7) as well as the highest number of cases (841) were reported in 1997. Comparison of two five-year periods, i.e. 1996-2000 and 2001-2005, showed a nearly one third decrease in the total of outbreaks and a half reduction in the total of cases in the latter. In view of the limited length of monitoring, it is not possible to say with certainty whether it is a random distribution or an actual trend. Almost two thirds of cases were diagnosed as acute gastroenteritis of probable infectious origin and other frequent waterborne diseases were viral hepatitis A and bacillary dysentery. When analyzing the described outbreaks, it

  15. BONE REGENERATION AFTER DEMINERALIZED BONE MATRIX AND CASTOR OIL (RICINUS COMMUNIS) POLYURETHANE IMPLANTATION

    Science.gov (United States)

    Leite, Fábio Renato Manzolli; Ramalho, Lizeti Toledo de Oliveira

    2008-01-01

    Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial. PMID:19089203

  16. Investigation on Thermal Properties of Kenaf Fibre Reinforced Polyurethane Bio-Composites

    Science.gov (United States)

    Athmalingam, Mathan; Vicki, W. V.

    2018-01-01

    This research focuses on the effect of Kenaf fibre on thermal properties of Polyurethane (PU) reinforced kenaf bio-composites. The samples were prepared using the polymer casting method with different percentages of kenaf fibre content (5 wt%, 10 wt%, 15 wt%). The thermal properties of Kenaf/PU bio-composite are determined through the Thermogravimetric Analysis and Differential Scanning Calorimeter test. The TGA results revealed that 10 wt% Kenaf/PU bio-composite appeared to be more stable. DSC results show that the glass transition temperature (Tg) value of 10 wt% Kenaf/PU composite is significant to pure polyurethane. It can be said that the thermal stability of 10 wt% Kenaf/PU bio-composite exhibits higher thermal stability compared to other samples.

  17. Polyurethane Production from Waste Bale Fibers

    Directory of Open Access Journals (Sweden)

    İbrahim BİLİCİ

    2017-12-01

    Full Text Available Nowadays, the methods of eliminating the pollution from wastes of the materials produced as much as the production methods are important. This requires efficiently use of sources economical and ecologically. Polyester based polymers, which is one of the most important consumed plastic materials in the world, have lots of number of recycling methods. Basically it is called chemical and physical recycling. Chemical recycle methods include glycolysis, aminolysis, methanolysis, hydrolysis and etc.. In this study aromatic polyester polyols produced from bale fiber wastes via glycolysis method. Zinc Acetate used as a catalysts and diethylene glycol used for the glycolysis reaction and moiety of glycol investigated as an experimental parameter. Polyurethane material produced via obtained polyol and TDI (Toluene di Isocyanate reaction. Obtained polyurethane material investigated via FTIR and TGA and compared with the commercial polyurethane. As a result, it has been decided that glycolysis is usable and applicable method for the waste bale fibers.

  18. The influence of montmorillonite and bentonite addition on thermal properties of polyurethanes based on aliphatic polycarbonate diols

    Czech Academy of Sciences Publication Activity Database

    Pavličević, J.; Špírková, Milena; Strachota, Adam; Meszaros Szecsenyi, K.; Lazić, N.; Budinski-Simendic, J.

    2010-01-01

    Roč. 509, 1/2 (2010), s. 73-80 ISSN 0040-6031 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : segmented polyurethanes * thermal stability * elastomers Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.908, year: 2010

  19. Epidemicity thresholds for water-borne and water-related diseases.

    Science.gov (United States)

    Mari, Lorenzo; Casagrandi, Renato; Rinaldo, Andrea; Gatto, Marino

    2018-06-14

    Determining the conditions that favor pathogen establishment in a host community is key to disease control and eradication. However, focusing on long-term dynamics alone may lead to an underestimation of the threats imposed by outbreaks triggered by short-term transient phenomena. Achieving an effective epidemiological response thus requires to look at different timescales, each of which may be endowed with specific management objectives. In this work we aim to determine epidemicity thresholds for some prototypical examples of water-borne and water-related diseases, a diverse family of infections transmitted either directly through water infested with pathogens or by vectors whose lifecycles are closely associated with water. From a technical perspective, while conditions for endemicity are determined via stability analysis, epidemicity thresholds are defined through generalized reactivity analysis, a recently proposed method that allows the study of the short-term instability properties of ecological systems. Understanding the drivers of water-borne and water-related disease dynamics over timescales that may be relevant to epidemic and/or endemic transmission is a challenge of the utmost importance, as large portions of the developing world are still struggling with the burden imposed by these infections. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. The development of polyurethane modified bitumen emulsions for cold mix applications

    OpenAIRE

    Carrera Páez, Virginia; Cuadri Vega, Antonio Abad; García Morales, Moisés; Partal López, Pedro

    2015-01-01

    Bitumen emulsions stand for an alternative paving practice to the traditional hot-mix asphalts. In addition, modified bitumen emulsions show a better performance than unmodified ones. This work studies the feasibility of obtaining polyurethane modified bitumen emulsions, in which an isocyanate-functionalized polyol constitutes the bitumen modifier (in varying concentration from 1 to 4 wt.%). Storage stability and high in-service performance are evaluated by means of evolution of droplet size ...

  1. Thermal Properties of Polyurethane-Polyisocyanurate Foams Based on Poly(ethylene terephthalate) Waste

    OpenAIRE

    Irena VITKAUSKIENĖ; Ričardas MAKUŠKA; Uldis STIRNA; Ugis CABULIS

    2011-01-01

    A series of polyurethane-polyisocyanurate (PU-PIR) foams synthesized from PET-waste-derived aromatic polyester polyols (APP) was studied using thermogravimetric analysis, Cone calorimeter and burning tests. The effect of chemical structure of the APP containing fragments of glycerol, adipic acid, poly(propylene glycol) or hexanediol on thermal stability and flame resistance of the PU-PIR foams was elucidated. PU-PIR foams prepared from APP containing fragments of glycerol and/or adipic acid h...

  2. Study of polyurethanes ageing offshore

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, Fabio G.; Sheldrake, Terry; Clevelario, Judimar; Pires, Fabio [Wellstream International, Panama City, FL (United States); Coutinho, Fernanda M.B. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

    2008-07-01

    The oil industry is one of the sectors with the highest number of production systems employing high technology. Brazil is worldwide renowned as a leader in oil and gas extraction in deep and ultra deep water. Inside the production chain, a great part the oil and gas produced is conveyed through flexible pipelines that connect the production wells to the platforms. There are two segments of these lines that receive different names according to their application characteristics. When the pipes are laid on the seabed in a static service condition, are called Flow lines and when they raise from the seabed to the platform in a dynamic service condition, are called Risers. The pipes designed for dynamic applications are equipped with Bend Stiffeners, components with conical form and in general with urethane basis, which has the function of providing a smooth stiffness transition between the flexible structure of the pipes and an extremely rigid structure, the platform, not allowing that this component infringes their minimum operation Bend Radius. According to Caire, the proper compression of curvature stiffeners and the material used in its manufacture is becoming increasingly important in industry due to its growing use and the occurrence of failures that have been recorded in recent years. This paper discusses the changes in the mechanical properties of polyurethanes by the hydrolysis during accelerated ageing, reaction of water with functional groups of the polymer chain, as well as mass variation, considering that these materials are designed for a service life exceeding twenty years for operation in water. (author)

  3. Waterborne Exophiala species causing disease in cold-blooded animals

    NARCIS (Netherlands)

    de Hoog, G.S.; Vicente, V.A.; Najafzadeh, M.J.; Harrak, M.J.; Badali, H.; Seyedmousavi, S.

    2011-01-01

    The majority of mesophilic waterborne species of the black yeast genus Exophiala (Chaetothyriales) belong to a single clade judging from SSU rDNA data. Most taxa are also found to cause cutaneous or disseminated infections in cold-blooded, water animals, occasionally reaching epidemic proportions.

  4. Waterborne Exophiala species causing disease in cold-blooded animals

    NARCIS (Netherlands)

    de Hoog, G.S.; Vicente, V.A.; Najafzadeh, M.J.; Harrak, M.J.; Badali, H.; Seyedmousavi, S.

    2012-01-01

    The majority of mesophilic waterborne species of the black yeast genus Exophiala (Chaetothyriales) belong to a single clade judging from SSU rDNA data. Most taxa are also found to cause cutaneous or disseminated infections in cold-blooded, water animals, occasionally reaching epidemic proportions.

  5. Oil-Acrylic hybrid latexes as binders for waterborne coatings

    NARCIS (Netherlands)

    Hamersveld, E.M.S.; Es, van J.J.G.S.; German, A.L.; Cuperus, F.P.; Weissenborn, P.; Hellgren, A.C.

    1999-01-01

    The combination of the characteristics of oil, or alkyd, emulsions and acrylic latexes in a waterborne binder has been the object of various studies in the past. Strategies for combining the positive properties of alkyds, e.g. autoxidative curing, gloss and penetration in wood, with the fast drying

  6. Oil-acrylic hybrid latexes as binders for waterborne coatings

    NARCIS (Netherlands)

    Hamersveld, van E.M.S.; Es, van J.; German, A.L.; Cuperus, F.P.; Weissenborn, P.; Hellgren, A.C.

    1999-01-01

    The combination of the characteristics of oil, or alkyd, emulsions and acrylic latexes in a waterborne binder has been the object of various studies in the past. Strategies for combining the positive properties of alkyds, e.g. autoxidative curing, gloss and penetration in wood, with the fast drying

  7. Genetic-based investigation of three prevalent waterborne protozoa ...

    African Journals Online (AJOL)

    SARAH

    2014-05-31

    May 31, 2014 ... 2014. Genetic –based investigations of three prevalent waterborne protozoa parasites in drinking water sources in Daloa, Cote d'Ivoire. 6536 step method, used for the detection of species belonging to Enterococcus genus. These membrane filtration (MF) based techniques do not require any additional.

  8. Water-borne protozoa parasites: The Latin American perspective.

    Science.gov (United States)

    Rosado-García, Félix Manuel; Guerrero-Flórez, Milena; Karanis, Gabriele; Hinojosa, María Del Carmen; Karanis, Panagiotis

    2017-07-01

    Health systems, sanitation and water access have certain limitations in nations of Latin America (LA): typical matters of developing countries. Water is often contaminated and therefore unhealthy for the consumers and users. Information on prevalence and detection of waterborne parasitic protozoa are limited or not available in LA. Only few reports have documented in this field during the last forty years and Brazil leads the list, including countries in South America and Mexico within Central America region and Caribbean islands. From 1979 to 2015, 16 outbreaks of waterborne-protozoa, were reported in Latin American countries. T. gondii and C. cayetanensis were the protozoa, which caused more outbreaks and Giardia spp. and Cryptosporidium spp. were the most frequently found protozoa in water samples. On the other hand, Latin America countries have not got a coherent methodology for detection of protozoa in water samples despite whole LA is highly vulnerable to extreme weather events related to waterborne-infections; although Brazil and Colombia have some implemented laws in their surveillance systems. It would be important to coordinate all surveillance systems in between all countries for early detection and measures against waterborne-protozoan and to establish effective and suitable diagnosis tools according to the country's economic strength and particular needs. Copyright © 2017 Elsevier GmbH. All rights reserved.

  9. Is Waterborne Disease Still an Issue in the US?

    Centers for Disease Control (CDC) Podcasts

    2012-08-27

    In this podcast, CDC’s Dr. Michael Beach discusses the changing face of waterborne disease in the US over the past century and how healthcare providers can apply this information to their patients.  Created: 8/27/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 10/22/2012.

  10. Genetic-based investigation of three prevalent waterborne protozoa ...

    African Journals Online (AJOL)

    Genetic-based investigation of three prevalent waterborne protozoa parasites in drinking water sources in Daloa district in Côte d'Ivoire. ... Low-income households should be aware of the risk of drinking water from wells and the need to boil or treated drinking water to avoid diarrheal diseases related thereto. Conclusion ...

  11. Synthesis of Polyurethane/Silica Modified Epoxy Polymer Based on 1,3-Propanediol for Coating Application

    Directory of Open Access Journals (Sweden)

    Lutviasari Nuraini

    2017-11-01

    Full Text Available Studies on the synthesis of polyurethane/silica modified epoxy polymer using 1,3-propanediol has been conducted. Synthesis of polymers made by reaction of tolonate and 1,3-propanediol (ratio NCO/OH=2.5 as the building blocks of polyurethane with diglycidyl ether bisphenol A (DGEBA epoxy and catalyst dibutyltin dilaurate (DBTL.The total weight of the polyurethane used was 20% (w/w of the total epoxy. Based on Fourier Transform Infrared (FTIR and 1H-Nuclear Magnetic Resonance (1H-NMR spectra indicated the existence of a new bond that is formed from the reaction of isocyanate group and hydroxyl group, where the hydroxyl groups derived from epoxy and 1,3-propanediol. The addition of silica (5, 10, and 15% w/w to epoxy into the epoxy-modified polyurethane has been carried out through sol-gel reaction of tetraethyl orthosilicate (TEOS. The isocyanate conversion rate for the addition of silica 5, 10, and 15% are 95.69; 100, and 100%, respectively. The morphology and element identification by Scanning Electron Microscopy/Energy Dispersive X-Ray Analysis (SEM/EDX, showed that Si element has been successfully added in the polymer. From the tensile strength and elongation analysis, also thermal stability analysis using Thermal Gravimetric Analyzer (TGA, the increase of silica amount into the polyurethane modified epoxy did not significantly affect to thermal properties, but decrease the tensile strength of the polymer.

  12. Synthesis and Physicochemical Behaviour of Polyurethane-Multiwalled Carbon Nanotubes Nanocomposites Based on Renewable Castor Oil Polyols

    Directory of Open Access Journals (Sweden)

    Alaa Ali

    2014-01-01

    Full Text Available Polyurethanes (PUs are high performance materials, with vast industrial and engineering applications. In this research, effects of Multiwalled Carbon Nanotubes (MWCNTs on physicochemical properties of Castor Oil based Polyurethanes (COPUs were studied. MWCNTs were added in different weight percentages (0% to 1% wt in a castor oil based polyurethane (COPUs-MWCNTs nanocomposites. The composition, structure, and morphology of polyurethanes were characterized by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, scanning electron microscopy (SEM, field emission scanning electron microscopy (FESEM, and element detection by energy dispersive spectroscopy (EDX analysis, respectively. Thermal stability was studied by thermogravimetric analysis (TGA. Barrier properties and surface area studies were investigated by nitrogen permeability machine and BET technique. Mechanical properties were calculated by tensile universal testing machine. Results showed well dispersed MWCNTs in polyurethane matrix at different weight percentages. The best results were obtained with 0.3 wt% of MWCNTs in the composite. Surface area studies revealed presence of very few pores which is in a good agreement with barrier permeability, reduced up to ~68% in 1 wt% and ~70% in 0.5 wt% of MWCNTs in polymer matrix, with respect to pure COPUs samples.

  13. A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles.

    Science.gov (United States)

    Cheng, Kuo-Wei; Hsu, Shan-Hui

    2017-01-01

    Superparamagnetic iron oxide nanoparticles (SPIO NPs) have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs) with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz) ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm) suspended in water. SPIO-PU hybrid NPs contained ~50-60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer) as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3]) or (9-(methylaminomethyl) anthracene [MAMA]) could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95%) without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg) and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers.

  14. Comparison of environmentally friendly, selective polyurethane catalysts

    Czech Academy of Sciences Publication Activity Database

    Strachota, Adam; Strachotová, Beata; Špírková, Milena

    2008-01-01

    Roč. 23, č. 6 (2008), s. 566-570 ISSN 1042-6914 R&D Projects: GA MPO FT-TA3/034 Institutional research plan: CEZ:AV0Z40500505 Keywords : amine catalyst * foam * gelation * kinetics * polyurethane Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.706, year: 2008

  15. Flexible optical fiber sensor based on polyurethane

    DEFF Research Database (Denmark)

    Kaysir, Md Rejvi; Stefani, Alessio; Lwin, Richard

    Polyurethane (PU) based hollow core fibers are investigated as optical sensors. The flexibility of PU fibers makes it suitable for sensing mechanical perturbations. We fabricated a PU fiber using the fiber drawing method, characterized the fiber and experimentally demonstrated a simple way...... to measure deformation, in the form of applied pressure....

  16. The reactive extrusion of thermoplastic polyurethane

    NARCIS (Netherlands)

    Verhoeven, Vincent Wilhelmus Andreas

    2006-01-01

    The objective of this thesis was to increase the understanding of the reactive extrusion of thermoplastic polyurethane. Overall, several issues were identified: • Using a relative simple extrusion model, the reactive extrusion process can be described. This model can be used to further investigate

  17. Inkjet printing of polyurethane colloidal suspensions

    NARCIS (Netherlands)

    Berg, van den A.M.J.; Smith, P.J.; Perelaer, J.; Schrof, W.; Koltzenburg, S.; Schubert, U.S.

    2007-01-01

    An aqueous 40 wt% dispersion of polyurethane has been successfully printed at room temperature using a piezoelectric inkjet printer. Simple layered structures, as well as dots, were made and subsequently analyzed using white-light interferometry. A single layer was found to have a structure height

  18. Preparation of eugenol-based polyurethane

    Science.gov (United States)

    Li, Yupeng; Luo, Fang; Cheng, Chuanjie

    2018-03-01

    The regenerative eugenol was used as the starting material to prepare diol species by two steps, with a total yield of 28%. Furthermore, the prepared diol reacts with 1,6-hexadiisocyanate(HDI) to afford the corresponding polyurethane (PU). The structure of intermediates and PU are characterized by 1H-NMR or IR.

  19. Self-stratifying antimicrobial polyurethane coatings

    NARCIS (Netherlands)

    Yagci, M.B.; Bolca, S.; Heuts, J.P.A.; Ming, W.; With, de G.

    2011-01-01

    In this work antimicrobial polyurethane coatings were prepared aiming at self-stratification. A hydroxyl end-capped liquid oligoester consisting of three equimolar diacids and an excess of 1,4-butanediol has been synthesized by a condensation reaction. A set of quaternary ammonium compounds (QACs)

  20. Rigid polyurethane and kenaf core composite foams

    Science.gov (United States)

    Rigid polyurethane foams are valuable in many construction applications. Kenaf is a bast fiber plant where the surface stem skin provides bast fibers whose strength-to-weight ratio competes with glass fiber. The higher volume product of the kenaf core is an under-investigated area in composite appli...

  1. Time-dependent crashworthiness of polyurethane foam

    Science.gov (United States)

    Basit, Munshi Mahbubul; Cheon, Seong Sik

    2018-05-01

    Time-dependent stress-strain relationship as well as crashworthiness of polyurethane foam was investigated under constant impact energy with different velocities, considering inertia and strain-rate effects simultaneously during the impact testing. Even though the impact energies were same, the percentage in increase in densification strain due to higher impact velocities was found, which yielded the wider plateau region, i.e. growth in crashworthiness. This phenomenon is analyzed by the microstructure of polyurethane foam obtained from scanning electron microscopy. The equations, coupled with the Sherwood-Frost model and the impulse-momentum theory, were employed to build the constitutive equation of the polyurethane foam and calculate energy absorption capacity of the foam. The nominal stress-strain curves obtained from the constitutive equation were compared with results from impact tests and were found to be in good agreement. This study is dedicated to guiding designer use polyurethane foam in crashworthiness structures such as an automotive bumper system by providing crashworthiness data, determining the crush mode, and addressing a mathematical model of the crashworthiness.

  2. Nanocomposites made from thermoplastic waterborne polyurethane and colloidal silica. The influence of nanosilica type and amount on the functional properties

    Czech Academy of Sciences Publication Activity Database

    Serkis, Magdalena; Špírková, Milena; Hodan, Jiří; Kredatusová, Jana

    2016-01-01

    Roč. 101, December (2016), s. 342-349 ISSN 0300-9440 R&D Projects: GA ČR(CZ) GA13-06700S Institutional support: RVO:61389013 Keywords : polymer-matrix composites (PMCs) * mechanical properties * microstructures Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.858, year: 2016

  3. Micelle-template synthesis of hollow silica spheres for improving water vapor permeability of waterborne polyurethane membrane

    OpenAIRE

    Bao, Yan; Wang, Tong; Kang, Qiaoling; Shi, Chunhua; Ma, Jianzhong

    2017-01-01

    Hollow silica spheres (HSS) with special interior spaces, high specific surface area and excellent adsorption and permeability performance were synthesized via micelle-template method using cetyl trimethyl ammonium bromide (CTAB) micelles as soft template and tetraethoxysilane (TEOS) as silica precursor. SEM, TEM, FT-IR, XRD, DLS and BET-BJH were carried out to characterize the morphology and structure of as-obtained samples. The results demonstrated that the samples were amorphous with a hol...

  4. Evaluation of the microstructure of waterborne poly(urethane-urea)s nanocomposites with hydrophilic clay (NWPUU)

    International Nuclear Information System (INIS)

    Miranda, Gisele dos S.; Delpech, Marcia C.; Reis, Rodrigo A. dos; Pereira, Alexandre Z.I; Coelho, Aline B.

    2015-01-01

    Waterborne poly(urethane-urea)s (WPUU) and respective nanocomposites based on hydrophilic clay (NWPUU) generally show segregation between hard and soft domains, in a greater or lesser extent, which directly influences the stability of the dispersion and affect the final properties of the material. Simple characterization techniques, such as infrared spectroscopy (FTIR) and X ray diffraction (XRD), employed in this study, can generate information about the microstructure and phase miscibility, using small amounts of material. The evaluation of the results obtained from the techniques showed that increments in rigid domains content and in the amount of internal emulsifier, as well as the presence of clay, decreased the size of the crystallites (crystallinity of the soft segments). (author)'

  5. Synthesis and properties of ionic polyurethane dispersions: influence of polyol molecular weight

    International Nuclear Information System (INIS)

    Valipour Ebrahimi, M.; Barikani, M.; Mohammad Seyed Mohaghegh, S.

    2006-01-01

    A series of water dispersible polyurethanes containing carboxylate anion as the hydrophilic pendant group were prepared from toluene diisocyanate (TDI), 1,4- butanediol (1,4-BDO), dimethylol propionic acid and different molecular weight of polytetramethylene glycol . IR Spectroscopy was used to check the end of polymerization reaction and characterization of polymer. The effect of polytetramethylene glycol molecular weight was studied on the particle size distribution, contact angle, and mechanical and thermal properties of the emulsion-cast films. Average particle size of prepared polyurethane emulsions decreases with increasing the polytetramethylene glycol molecular weight. Tensile strength and hardness decrease and elongation-at-break and contact angle increase with increase of the polytetramethylene glycol molecular weight. Thermal property and thermal stability are also effected by variation of polytetramethylene glycol molecular weight. The thermal stability increases with increasing polytetramethylene glycol molecular weight. Glass transition temperature (T g ) moved toward the lower temperatures by increasing molecular weight of the polyol. Decrease in T g and tensile properties are interpreted in terms of the decrease in hard segments and the increase in chain flexibility and phase separation in high molecular weight polytetramethylene glycol based polyurethane

  6. The use of polyurethane materials in the surgery of the spine: a review.

    Science.gov (United States)

    St John, Kenneth R

    2014-12-01

    The spine contains intervertebral discs and the interspinous and longitudinal ligaments. These structures are elastomeric or viscoelastic in their mechanical properties and serve to allow and control the movement of the bony elements of the spine. The use of metallic or hard polymeric devices to replace the intervertebral discs and the creation of fusion masses to replace discs and/or vertebral bodies changes the load transfer characteristics of the spine and the range of motion of segments of the spine. The purpose of the study was to survey the literature, regulatory information available on the Web, and industry-reported device development found on the Web to ascertain the usage and outcomes of the use of polyurethane polymers in the design and clinical use of devices for spine surgery. A systematic review of the available information from all sources concerning the subject materials' usage in spinal devices was conducted. A search of the peer-reviewed literature combining spinal surgery with polyurethane or specific types and trade names of medical polyurethanes was performed. Additionally, information available on the Food and Drug Administration Web site and for corporate Web sites was reviewed in an attempt to identify pertinent information. The review captured devices that are in testing or have entered clinical practice that use elastomeric polyurethane polymers as disc replacements, dynamic stabilization of spinal movement, or motion limitation to relieve nerve root compression and pain and as complete a listing as possible of such devices that have been designed or tested but appear to no longer be pursued. This review summarizes the available information about the uses to which polyurethanes have been tested or are being used in spinal surgery. The use of polyurethanes in medicine has expanded as modifications to the stability of the polymers in the physiological environment have been improved. The potential for the use of elastomeric materials to more

  7. Synthesis and characterization of polyurethane/CdS-SiO 2 nanocomposites via ultrasonic process

    Science.gov (United States)

    Chen, Jing; Zhou, Yu-Ming; Nan, Qiu-Li; Ye, Xiao-Yun; Sun, Yan-Qing; Wang, Zhi-Qiang; Zhang, Shi-Ming

    2008-12-01

    In this study, the high-intensity ultrasound was applied in the preparation of chiral polyurethane/CdS-SiO 2 nanocomposites. The polyurethane/CdS-SiO 2 nanocomposites were analyzed by powder X-ray diffraction, thermogravimetric analysis (TGA), TEM and SEM. The results indicated that the heat stability of the nanocomposites was improved in the presence of CdS-SiO 2 core-shell nanoparticles. The infrared emissivity (8-14 μm) study revealed that the nanocomposites possessed much lower infrared values compared with those of the neat polymers and nanoparticles, respectively. A possible mechanism of ultrasonic induced composite reaction was proposed based on the experimental results.

  8. Synthesis and characterization of polyurethane/CdS-SiO2 nanocomposites via ultrasonic process

    International Nuclear Information System (INIS)

    Chen Jing; Zhou Yuming; Nan Qiuli; Ye Xiaoyun; Sun Yanqing; Wang Zhiqiang; Zhang Shiming

    2008-01-01

    In this study, the high-intensity ultrasound was applied in the preparation of chiral polyurethane/CdS-SiO 2 nanocomposites. The polyurethane/CdS-SiO 2 nanocomposites were analyzed by powder X-ray diffraction, thermogravimetric analysis (TGA), TEM and SEM. The results indicated that the heat stability of the nanocomposites was improved in the presence of CdS-SiO 2 core-shell nanoparticles. The infrared emissivity (8-14 μm) study revealed that the nanocomposites possessed much lower infrared values compared with those of the neat polymers and nanoparticles, respectively. A possible mechanism of ultrasonic induced composite reaction was proposed based on the experimental results.

  9. Polyurethane Membranes Modified with Isopropyl Myristate as a Potential Candidate for Encapsulating Electronic Implants: A Study of Biocompatibility and Water Permeability

    Directory of Open Access Journals (Sweden)

    Deepen Paul

    2010-07-01

    Full Text Available Medical polyurethanes have shown good bio-stability and mechanical properties and have been used as coating for implantable medical devices. However, despite their excellent properties, they are relatively permeable to liquid water and water vapour which is a drawback for electronic implant encapsulation. In this study polyether polyurethanes with different soft segment molecular weights were modified by incorporating isopropyl myristate (IPM, as a hydrophobic modifying agent, and the effect of IPM on water resistant and biocompatibility of membranes were investigated. IPM changed the surface properties of the polyurethane film and reduced its surface energy. Polyurethane films were found to be stable with IPM concentrations of 1–5 wt% based upon their chemistry; however it leached out in BSA at higher concentrations. Though, low concentrations of IPM reduced both liquid water and water vapour permeability; at higher IPM content liquid permeability did not improved significantly. In general, the polyurethane materials showed much lower water permeability compared with currently used silicone packaging material for electronic implants. In addition, cytotoxicity assessment of IPM containing polyurethanes showed no evidence of cytotoxcity up to 5 wt% IPM.

  10. Marine biofouling resistance of polyurethane with biodegradation and hydrolyzation.

    Science.gov (United States)

    Xu, Wentao; Ma, Chunfeng; Ma, Jielin; Gan, Tiansheng; Zhang, Guangzhao

    2014-03-26

    We have prepared polyurethane with poly(ε-caprolactone) (PCL) as the segments of the main chain and poly(triisopropylsilyl acrylate) (PTIPSA) as the side chains by a combination of radical polymerization and a condensation reaction. Quartz crystal microbalance with dissipation studies show that polyurethane can degrade in the presence of enzyme and the degradation rate decreases with the PTIPSA content. Our studies also demonstrate that polyurethane is able to hydrolyze in artificial seawater and the hydrolysis rate increases as the PTIPSA content increases. Moreover, hydrolysis leads to a hydrophilic surface that is favorable to reduction of the frictional drag under dynamic conditions. Marine field tests reveal that polyurethane has good antifouling ability because polyurethane with a biodegradable PCL main chain and hydrolyzable PTIPSA side chains can form a self-renewal surface. Polyurethane was also used to carry and release a relatively environmentally friendly antifoulant, and the combined system exhibits a much higher antifouling performance even in a static marine environment.

  11. Preparation and characterization of new biologically active polyurethane foams.

    Science.gov (United States)

    Savelyev, Yuri; Veselov, Vitali; Markovskaya, Ludmila; Savelyeva, Olga; Akhranovich, Elena; Galatenko, Natalya; Robota, Ludmila; Travinskaya, Tamara

    2014-12-01

    Biologically active polyurethane foams are the fast-developed alternative to many applications of biomedical materials. Due to the polyurethane structure features and foam technology it is possible to incorporate into their structure the biologically active compounds of target purpose via structural-chemical modification of macromolecule. A series of new biologically active polyurethane foams (PUFs) was synthesized with polyethers (MM 2500-5000), polyesters MM (500-2200), 2,4(2,6) toluene diisocyanate, water as a foaming agent, catalysts, foam stabilizers and functional compounds. Different functional compounds: 1,4-di-N-oxy-2,3-bis-(oxymethyl)-quinoxaline (DOMQ), partial sodium salt of poly(acrylic acid) and 2,6-dimethyl-N,N-diethyl aminoacetatanilide hydrochloride were incorporated into the polymer structure/composition due to the chemical and/or physical bonding. Structural peculiarities of PUFs were studied by FTIR spectroscopy and X-ray scattering. Self-adhesion properties of PUFs were estimated by measuring of tensile strength at break of adhesive junction. The optical microscopy method was performed for the PUF morphology studies. Toxicological estimation of the PUFs was carried out in vitro and in vivo. The antibacterial action towards the Gram-positive and Gram-negative bacteria (Escherichia coli ATC 25922, E. coli ATC 2150, Klebsiella pneumoniae 6447, Staphylococcus aureus 180, Pseudomonas aeruginosa 8180, Proteus mirabilis F 403, P. mirabilis 6054, and Proteus vulgaris 8718) was studied by the disc method on the solid nutrient. Physic-chemical properties of the PUFs (density, tensile strength and elongation at break, water absorption and vapor permeability) showed that all studied PUFs are within the operational requirements for such materials and represent fine-cellular foams. Spectral studies confirmed the incorporation of DOMQ into the PUF's macrochain. PUFs are characterized by microheterogeneous structure. They are antibacterially active, non

  12. Urinary catheter with polyurethane coating modified by ion implantation

    International Nuclear Information System (INIS)

    Kondyurina, I.; Nechitailo, G.S.; Svistkov, A.L.; Kondyurin, A.; Bilek, M.

    2015-01-01

    A low friction urinary catheter that could be used without a lubricant is proposed in this work. A polyurethane coating was synthesised on the surface of a metal guide wire catheter. Ion implantation was applied to surface modify the polyurethane coating. FTIR ATR, wetting angle, AFM and friction tests were used for analysis. Low friction was found to be provided by the formation of a hard carbonised layer on the polyurethane surface

  13. Degradation mechanism of polyurethane foam induced by electron beam irradiation

    International Nuclear Information System (INIS)

    Huang Wei; Fu Yibei; Bian Zhishang; He Meiying

    2002-01-01

    The degradation mechanism of irradiated polyurethane foam has been studied in detail. The changes of chemical structure and micro-phase separation have been determined by DTG. The gas products from irradiated samples are analyzed quantitatively and qualitatively by GC. The degradation mechanism of irradiated polyurethane foam has been deduced according to the experimental results. It provides some basis of the application on the polyurethane in the radiation field

  14. Rigid Polyurethane Foam Reinforced Coconut Coir Fiber Properties

    OpenAIRE

    Mohd Azham Azmi

    2012-01-01

    This research work studied the properties of composite foam panels. Coconut coir fibers were used as reinforcement in polyurethane (PU) foam in order to increase the properties of foam. This composite foam panels were fabricated by using polyurethane molded method. The polyurethane foam panels reinforced from 5 to 20wt% coconut coir were produced to investigate the physical and mechanical test via density test and three point bending test respectively. It was found that the density test resul...

  15. Waterborne Disease Case Investigation: Public Health Nursing Simulation.

    Science.gov (United States)

    Alexander, Gina K; Canclini, Sharon B; Fripp, Jon; Fripp, William

    2017-01-01

    The lack of safe drinking water is a significant public health threat worldwide. Registered nurses assess the physical environment, including the quality of the water supply, and apply environmental health knowledge to reduce environmental exposures. The purpose of this research brief is to describe a waterborne disease simulation for students enrolled in a public health nursing (PHN) course. A total of 157 undergraduate students completed the simulation in teams, using the SBAR (Situation-Background-Assessment-Recommendation) reporting tool. Simulation evaluation consisted of content analysis of the SBAR tools and debriefing notes. Student teams completed the simulation and articulated the implications for PHN practice. Student teams discussed assessment findings and primarily recommended four nursing interventions: health teaching focused on water, sanitation, and hygiene; community organizing; collaboration; and advocacy to ensure a safe water supply. With advanced planning and collaboration with partners, waterborne disease simulation may enhance PHN education. [J Nurs Educ. 2017;56(1):39-42.]. Copyright 2017, SLACK Incorporated.

  16. Climate Change Impacts on Waterborne Diseases: Moving Toward Designing Interventions.

    Science.gov (United States)

    Levy, Karen; Smith, Shanon M; Carlton, Elizabeth J

    2018-06-01

    Climate change threatens progress achieved in global reductions of infectious disease rates over recent decades. This review summarizes literature on potential impacts of climate change on waterborne diseases, organized around a framework of questions that can be addressed depending on available data. A growing body of evidence suggests that climate change may alter the incidence of waterborne diseases, and diarrheal diseases in particular. Much of the existing work examines historical relationships between weather and diarrhea incidence, with a limited number of studies projecting future disease rates. Some studies take social and ecological factors into account in considerations of historical relationships, but few have done so in projecting future conditions. The field is at a point of transition, toward incorporating social and ecological factors into understanding the relationships between climatic factors and diarrheal diseases and using this information for future projections. The integration of these components helps identify vulnerable populations and prioritize adaptation strategies.

  17. Palm oil based polyols for acrylated polyurethane production

    International Nuclear Information System (INIS)

    Rida Tajau; Mohd Hilmi Mahmood; Mek Zah Salleh; Khairul Zaman Mohd Dahlan; Rosley Che Ismail

    2006-01-01

    Palm oil becomes important renewable resources for the production of polyols for the polyurethane manufacturing industry. The main raw materials used for the production of acrylated polyurethane are polyols, isocyanates and hydroxyl terminated acrylate compounds. In these studies, polyurethane based natural polymer (palm oil), i.e., POBUA (Palm Oil Based Urethane Acrylate) were prepared from three different types of palm oil based polyols i.e., epoxidised palm oil (EPOP), palm oil oleic acid and refined, bleached and deodorized (RBD) palm olein based polyols. The performances of these three acrylated polyurethanes when used for coatings and adhesives were determined and compared with each other. (Author)

  18. Crosslinked polyurethanes based on hyperbranched polymers

    Directory of Open Access Journals (Sweden)

    Vuković Jasna

    2008-01-01

    Full Text Available In this paper, two samples of polyurethane (PU crosslinked with hydroxy -functonal hyperbranched aliphatic polyester of the second pseudo generation were investigated. For the synthesis of these crosslinked PUs two different macrodiols were used: poly(tetramethyleneoxide (PTMO for PUPTMO and ethylene oxide-poly(dimethylsiloxane-ethylene oxide (PDMS-EO for PUPDMS-EO sample. Synthesized samples behave as elastomers and have yellow color. Obtained results show that swelling degree of the sample PUPDMS-EO in N-methyl-2-pyrrolidinon (NMP determined at room temperature is higher than for the sample PUPTMO. It has been also observed that thermal properties of these polyurethane networks can be changed by incorporation of siloxane sequences in their structure.

  19. Study of the catalytic selectivity of an aqueous two-component polyurethane system by ftir spectroscopy

    Directory of Open Access Journals (Sweden)

    Stamenković Jakov V.

    2003-01-01

    Full Text Available The difficulty in formulating a two component waterborne polyurethane, is the isocyanate-water side reaction, which can lead to gassing/foaming, loss of isocyanate functionality, low gloss and a reduced pot life. To compensate for this side reaction, these formulations usually contain a large excess of isocyanate. Tin compounds, especially dibutyltin dilaurate, are widely used in coatings as catalysts for the isocyanate/hydroxyl reaction. Because of the high aquatic toxicity of some organotin compounds, there has been an attempt to ban organotin compounds from all coating applications. As a general rule, organotin catalysts are not selective, they catalyze the reaction of isocyanates with both hydroxyl groups and water and also catalyze the hydrolysis of ester groups. One novel approach to control the water side reaction is the use of catalysts which selectively catalyze the isocyanate-polyol reaction and not the isocyanate-water reaction. The selectivity of a variety of metal catalysts (metal octoates, metal acetylacetonates and mangan chelates with mixed ligands to catalyze the preferred reaction was measured using the FTIR method.

  20. Novel metallomesogenic polyurethanes: Synthesis, characterization and properties

    International Nuclear Information System (INIS)

    Senthilkumar, Natarajan; Narasimhaswamy, Tanneru; Kim, Il-Jin

    2012-01-01

    A series of tetradentate Schiff base metallomesogenic diols were synthesized from two simple dihydroxy benzenes. The metallomesogenic diol was constructed from three ring containing mesogen linked through ester and azomethine with terminal hydroxy group. This upon complexation with copper(II) formed metallomesogenic diol with varying terminal chain length. A series of metallomesogenic polyurethanes were synthesized using these metallomesogenic diols as chain extenders for the prepolymers based on polytetramethylene glycol (PTMG) of varying molecular weight (M n = 650, 2000) and 2,4-toluene diisocyanate (TDI), or 4,4′-methylene bis(phenyl isocyanate) (MDI). The molar ratio of metallomesogenic diol and PTMG were varied in the polyurethane to find their role in liquid crystalline and mechanical properties. Extensive characterization of all metallomesogenic compounds and intermediates were carried out by FT-IR, 1 H and 13 C NMR, EPR, VSM, Mass (EI and FAB) and UV–visible spectroscopy. Hot stage polarizing microscope and differential scanning calorimetry were used to ensure the phase characteristics such as nature of phase, melting and clearing temperatures and phase range. The appearance of enantiotropic smectic A phases indicated high molecular polarizability of the core due to the metal ion. - Highlights: ► Design and synthesis of metallomesogenic diols. ► Metallomesogenic polyurethanes were prepared using these diols as chain extenders. ► Liquid crystalline and mechanical properties were studied. ► A square pyramidal structure for the copper(II) complexes have been proposed. ► Polyurethanes exhibited enantiotropic smectic A phases.

  1. Structures and Properties of Polyurethanes. Part II,

    Science.gov (United States)

    1979-03-23

    effect was observed for polymethyl methacrylate (222, 2721. The polyol, which contain fluorine , decrease adhesion, in spite DOC = 79011112 PAGE S4% of...small differences in the hardness of films on the basis of the fluorine -bearing polyol and generally accepted polyol. Is investigated the etfect ot...polyurethane, to rigid surface. DOC 79011112 P A * S The effect of the solvent, utilized for obtaining the varnish , on adhesion is investigated in

  2. Biodegradability of polyurethane/polysaccharide blends

    International Nuclear Information System (INIS)

    Mothe, Cheila G.; Leite, Selma G.

    2001-01-01

    Biodegradable polymers for use in environmental waste-management has been the subject of much discussion over the last few years. Polyurethane mixtures with polysaccharide (80/20 and 90/10 w/w ) have been prepared and films obtained. These films were inoculated, according to ASTM G22-76 rule and analysed by thermogravimetry and scanning electronic microscopy (SEM). The results are discussed in terms of thermal degradation and biodegradability. (author)

  3. Epoxy polyurethane nanocomposites filled with fullerite

    International Nuclear Information System (INIS)

    Rozhnova, R.A.; Galatenko, N.A.; Lukashevich, S.A.; Shirokov, O.D.; Levenets', Je.G.

    2015-01-01

    New nanocomposite materials based on epoxy polyurethane (EPU) containing nanoscale fullerite in its composition are produced. The influence of small impurities of fullerite on physical and mechanical properties of the nanocomposites is established. The effect of a nanofiller and its concentration on the structure and properties of the composite and the ability to biodegradation in vitro is studied. The developed nanocomposites exhibit the biodegradability, and the presence of nanofillers in the EPU facilitates the course of the process

  4. Mechanical and thermal properties of castor oil polyurethane bone cement after gamma irradiation;Propriedades mecanicas e termicas de poliuretanas derivadas do oleo de mamona usadas como cimento osseo depois da irradiacao com radiacao gamma

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, E.C. [Universidade Tecnologica Federal do Parana (DF/UTFPR), Curitiba, PR (Brazil). Dept. de Fisica; Soboll, D.S. [Universidade Tecnologica Federal Parana (CPGEI/UTFPR), Curitiba, PR (Brazil); Chierice, G.O.; Claro Neto, S. [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica; Lepiesnki, C.M. [Universidade Federal do Parana (DF/UFPR), Curitiba, PR (Brazil). Dept. de Fisica; Nascimento, E.M. [Universidade Tecnologica Federal do Parana (DM/UTFPR), Curitiba (Brazil). Dept. de Mecanica

    2009-07-01

    Polyurethanes from castor oil are being employed as bone cement in medical applications. In this work the thermal and mechanical properties of gamma irradiated polyurethanes derivative from castor oil were investigated by instrumented indentation, thermogravimetry and scanning electron microscopy. A slightly increase in hardness is observed only for doses as high as 100 kGy. Thermal analysis indicates stability at human body temperature. The glass transition temperature has small changes after gamma irradiation. (author)

  5. Design of Xylose-Based Semisynthetic Polyurethane Tissue Adhesives with Enhanced Bioactivity Properties.

    Science.gov (United States)

    Balcioglu, Sevgi; Parlakpinar, Hakan; Vardi, Nigar; Denkbas, Emir Baki; Karaaslan, Merve Goksin; Gulgen, Selam; Taslidere, Elif; Koytepe, Suleyman; Ates, Burhan

    2016-02-01

    Developing biocompatible tissue adhesives with high adhesion properties is a highly desired goal of the tissue engineering due to adverse effects of the sutures. Therefore, our work involves synthesis, characterization, adhesion properties, protein adsorption, in vitro biodegradation, in vitro and in vivo biocompatibility properties of xylose-based semisynthetic polyurethane (NPU-PEG-X) bioadhesives. Xylose-based semisynthetic polyurethanes were developed by the reaction among 4,4'-methylenebis(cyclohexyl isocyanate) (MCI), xylose and polyethylene glycol 200 (PEG). Synthesized polyurethanes (PUs) showed good thermal stability and high adhesion strength. The highest values in adhesion strength were measured as 415.0 ± 48.8 and 94.0 ± 2.8 kPa for aluminum substrate and muscle tissue in 15% xylose containing PUs (NPU-PEG-X-15%), respectively. The biodegradation of NPU-PEG-X-15% was also determined as 19.96 ± 1.04% after 8 weeks of incubation. Relative cell viability of xylose containing PU was above 86%. Moreover, 10% xylose containing NPU-PEG-X (NPU-PEG-X-10%) sample has favorable tissue response, and inflammatory reaction between 1 and 6 weeks implantation period. With high adhesiveness and biocompatibility properties, NPU-PEG-X can be used in the medical field as supporting materials for preventing the fluid leakage after abdominal surgery or wound closure.

  6. Mechanical behavior of fouled polyurethane stabilized ballast (PSB).

    Science.gov (United States)

    2012-11-01

    The United State (US) Department of Transportation (DOT) estimates that the demand for rail freight transportation (tonnage) will : increase 88% by 2035, North American railroads spend about $3.4 billion every year on track substructure maintenance a...

  7. Fluorinated Polyurethane Scaffolds for 19F Magnetic Resonance Imaging

    NARCIS (Netherlands)

    Lammers, Twan; Mertens, Marianne E.; Schuster, Philipp; Rahimi, Khosrow; Shi, Yang; Schulz, Volkmar; Kuehne, Alexander J.C.; Jockenhoevel, Stefan; Kiessling, Fabian

    2017-01-01

    Researchers used fluorinated polyurethane scaffolds for 19F magnetic resonance imaging. They generated a novel fluorinated polymer based on thermoplastic polyurethane (19F -TPU) which possesses distinct properties rendering it suitable for fluorine-based MRI. The 19F -TPU is synthesized from a

  8. Molecular simulation of fibronectin adsorption onto polyurethane surfaces

    Science.gov (United States)

    Polyethylene glycol-based polyurethanes have been widely used in biomedical applications, however are prone to swelling. A natural polyol, castor oil can be incorporated into these polyurethanes to control the degree of the swelling, which alters mechanical properties and protein adsorption characte...

  9. Optimization of polyurethane foam cube in enhancing the ...

    African Journals Online (AJOL)

    Attachment of microalgae biomass to polyurethane foam material is believed could reduce the cost and time needed for harvesting process in making it reliable to be used in industry for biodiesel production. This paper aim to optimize the usage of polyurethane for higher attachment of microalgae biomass yield in term of it ...

  10. Development, optimisation and application of polyurethane foams as new polymeric phases for stir bar sorptive extraction.

    Science.gov (United States)

    Neng, N R; Pinto, M L; Pires, J; Marcos, P M; Nogueira, J M F

    2007-11-09

    In this contribution, polyurethane foams are proposed as new polymeric phases for stir bar sorptive extraction (SBSE). Assays performed for polyurethane synthesis demonstrated that four series of formulations (P(1), P(2), P(3) and P(4)) present remarkable stability and excellent mechanical resistance to organic solvents. For polymer clean-up treatment, acetonitrile proved to be the best solvent under sonification, ensuring the reduction of the contamination and interferences. SBSE assays performed on these polyurethane polymers followed by liquid desorption and high-performance liquid chromatography-diode array detection (LD-HPLC-DAD) or large volume injection-capillary gas chromatography-mass spectrometry (LD-LVI-GC-MS), showed that P(2) presents the best recovery yields for atrazine, 2,3,4,5-tetrachlorophenol and fluorene, used as model compounds in water samples at a trace level. SBSE(P(2)) assays performed on this polymer mixed up with several adsorbent materials, i.e. activated carbon, a mesoporous material and a calixarene, did not bring any advantages in relation with the polymeric matrix alone. The comparison between assays performed by SBSE(P(2)) and by the conventional SBSE(PDMS) showed much better performance for the former phase on aqueous samples spiked with atrazine, 2,3,4,5-tetrachlorophenol and fluorene, in which the foremost two analytes present recovery values 3- and 10-fold higher, respectively. The polyurethanes proposed as new polymeric phases for SBSE provided powerful capabilities for the enrichment of organic compounds from aqueous matrices, showing to be indicated mainly in the case of the more polar analytes.

  11. Biodegradative Activities of Selected Environmental Fungi on a Polyester Polyurethane Varnish and Polyether Polyurethane Foams.

    Science.gov (United States)

    Álvarez-Barragán, Joyce; Domínguez-Malfavón, Lilianha; Vargas-Suárez, Martín; González-Hernández, Ricardo; Aguilar-Osorio, Guillermo; Loza-Tavera, Herminia

    2016-09-01

    Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm(-1)) and N-H bonds (1,540 and 1,261 cm(-1)), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU. Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and

  12. Nasolacrimal Polyurethane Stent: Complications with CT Correlation

    International Nuclear Information System (INIS)

    Pinto, Isabel T.; Paul, Laura; Grande, Carlos

    1998-01-01

    Purpose: To evaluate initial results in patients with epiphora secondary to obstruction of the nasolacrimal duct treated by placement of a polyurethane stent, and to discuss the technical problems and complications arising during the procedure, with visualization of the anatomy of the drainage apparatus using computed tomography (CT). Methods: We inserted 20 polyurethane Song stents under fluoroscopic guidance after dacryocystography in 19 patients with grade 3-4 epiphora caused by idiopathic obstruction of the nasolacrimal duct. CT scans were obtained following stent placement in all patients. Results: We focus on the technical problems and complications that arose during these procedures. During negotiation of the guidewire past the obstruction at the level of the junction of the duct with the lacrimal sac, the guidewire created a false passage in a posterior suborbital direction in two cases and towards the posterior midline in another. In all cases the guidewire was withdrawn and reinserted through the proper anatomic route without further difficulty or complications. In two cases the stent was improperly positioned wholly or partially outside the nasolacrimal system (one medially, one posteriorly). In one case the stent was removed and reinserted; in the other it remains in place and functional. CT was performed in all these cases to ensure proper anatomic alignment and determine what had gone wrong. The epiphora was completely resolved in 13 cases and partially relieved in four; there were three cases of stent obstruction. Epistaxis of short duration (1 hr) occurred in seven patients and headache in one. Conclusions: Treatment of epiphora with polyurethane stents is a technique that is well tolerated by patients and achieves a high success rate, yet problems in placement may be encountered. Though no major consequences for patients are involved, cognizance of such difficulties is important to avoid incorrect positioning of stents

  13. Mechanical Characterization of Rigid Polyurethane Foams

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei-Yang [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Mechanics of Materials

    2014-12-01

    Foam materials are used to protect sensitive components from impact loading. In order to predict and simulate the foam performance under various loading conditions, a validated foam model is needed and the mechanical properties of foams need to be characterized. Uniaxial compression and tension tests were conducted for different densities of foams under various temperatures and loading rates. Crush stress, tensile strength, and elastic modulus were obtained. A newly developed confined compression experiment provided data for investigating the foam flow direction. A biaxial tension experiment was also developed to explore the damage surface of a rigid polyurethane foam.

  14. The impact of waterborne LPG imports on US markets

    International Nuclear Information System (INIS)

    Lindsey, L.

    1994-01-01

    After a winter like most of the US has gone through this year it is certainly apropos to discuss the effect of waterborne LPG imports on the market. Due to time constraints this paper will be limited to global LPG activity as it relates to the US. To provide some credibility to the following comments, it should be stated that Commercial Services Company tracks every large LPG carrier in the world from the LPG lifting point to it's discharge destination and the commercial activity involved in the delivery

  15. A review: fabrication of porous polyurethane scaffolds.

    Science.gov (United States)

    Janik, H; Marzec, M

    2015-03-01

    The aim of tissue engineering is the fabrication of three-dimensional scaffolds that can be used for the reconstruction and regeneration of damaged or deformed tissues and organs. A wide variety of techniques have been developed to create either fibrous or porous scaffolds from polymers, metals, composite materials and ceramics. However, the most promising materials are biodegradable polymers due to their comprehensive mechanical properties, ability to control the rate of degradation and similarities to natural tissue structures. Polyurethanes (PUs) are attractive candidates for scaffold fabrication, since they are biocompatible, and have excellent mechanical properties and mechanical flexibility. PU can be applied to various methods of porous scaffold fabrication, among which are solvent casting/particulate leaching, thermally induced phase separation, gas foaming, emulsion freeze-drying and melt moulding. Scaffold properties obtained by these techniques, including pore size, interconnectivity and total porosity, all depend on the thermal processing parameters, and the porogen agent and solvents used. In this review, various polyurethane systems for scaffolds are discussed, as well as methods of fabrication, including the latest developments, and their advantages and disadvantages. Copyright © 2014. Published by Elsevier B.V.

  16. A holistic passive integrative sampling approach for assessing the presence and potential impacts of waterborne environmental contaminants

    Science.gov (United States)

    Petty, J.D.; Huckins, J.N.; Alvarez, D.A.; Brumbaugh, W. G.; Cranor, W.L.; Gale, R.W.; Rastall, A.C.; Jones-Lepp, T. L.; Leiker, T.J.; Rostad, C. E.; Furlong, E.T.

    2004-01-01

    As an integral part of our continuing research in environmental quality assessment approaches, we have developed a variety of passive integrative sampling devices widely applicable for use in defining the presence and potential impacts of a broad array of contaminants. The semipermeable membrane device has gained widespread use for sampling hydrophobic chemicals from water and air, the polar organic chemical integrative sampler is applicable for sequestering waterborne hydrophilic organic chemicals, the stabilized liquid membrane device is used to integratively sample waterborne ionic metals, and the passive integrative mercury sampler is applicable for sampling vapor phase or dissolved neutral mercury species. This suite of integrative samplers forms the basis for a new passive sampling approach for assessing the presence and potential toxicological significance of a broad spectrum of environmental contaminants. In a proof-of-concept study, three of our four passive integrative samplers were used to assess the presence of a wide variety of contaminants in the waters of a constructed wetland, and to determine the effectiveness of the constructed wetland in removing contaminants. The wetland is used for final polishing of secondary-treatment municipal wastewater and the effluent is used as a source of water for a state wildlife area. Numerous contaminants, including organochlorine pesticides, polycyclic aromatic hydrocarbons, organophosphate pesticides, and pharmaceutical chemicals (e.g., ibuprofen, oxindole, etc.) were detected in the wastewater. Herein we summarize the results of the analysis of the field-deployed samplers and demonstrate the utility of this holistic approach.

  17. Stable Photocatalytic Paints Prepared from Hybrid Core-Shell Fluorinated/Acrylic/TiO2 Waterborne Dispersions

    Directory of Open Access Journals (Sweden)

    Audrey Bonnefond

    2016-10-01

    Full Text Available The contamination of air and water is one of the major concerns towards the development of a sustainable world in the 21st century. In this context many efforts are devoted to the design of photocatalytic paints able to degrade chemical and biological impurities present in air and water. In this work, the photocatalytic activity of hybrid films formed from the blends of pure acrylic or core/shell fluorinated/acrylic waterborne dispersions and photocatalytic titanium dioxide (TiO2 nanoparticle dispersions was first assessed. The films show photocatalytic activity (inactivation of the Escherichia coli bacteria under UV irradiation at the substrate-film interface, but very reduced activity in the air-film interface due to the substantially lower amount of the TiO2 nanoparticles in the vicinity of this interface. In a second step, the fluorinated/(methacrylic core-shell hybrid dispersions were used as binders in the formulation of waterborne photocatalytic paints and the stability of the paints, in terms of gloss retain and color change, was assessed during 5000 hours of accelerated weathering tests (QUV-B. Although a decrease in gloss retention and increased color change occurs during the first 1000 hours of exposure, no further change of these properties takes place, which is an excellent indication of stable photocatalytic paints.

  18. Detection of Waterborne Viruses Using High Affinity Molecularly Imprinted Polymers.

    Science.gov (United States)

    Altintas, Zeynep; Gittens, Micah; Guerreiro, Antonio; Thompson, Katy-Anne; Walker, Jimmy; Piletsky, Sergey; Tothill, Ibtisam E

    2015-07-07

    Molecularly imprinted polymers (MIPs) are artificial receptor ligands which can recognize and specifically bind to a target molecule. They are more resistant to chemical and biological damage and inactivation than antibodies. Therefore, target specific-MIP nanoparticles are aimed to develop and implemented to biosensors for the detection of biological toxic agents such as viruses, bacteria, and fungi toxins that cause many diseases and death due to the environmental contamination. For the first time, a molecularly imprinted polymer (MIP) targeting the bacteriophage MS2 as the template was investigated using a novel solid-phase synthesis method to obtain the artificial affinity ligand for the detection and removal of waterborne viruses through optical-based sensors. A high affinity between the artificial ligand and the target was found, and a regenerative MIP-based virus detection assay was successfully developed using a new surface plasmon resonance (SPR)-biosensor which provides an alternative technology for the specific detection and removal of waterborne viruses that lead to high disease and death rates all over the world.

  19. Characterization of polyurethane/organophilic montmorillonite nanocomposites by low field NMR; Caracterizacao de nanocompositos de poliuretano/montmorilonita organofilica por RMN de baixo campo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcos Anacleto da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Laboratorio de Nanocompositos Polimericos; Tavares, Maria I.B.; Nascimento, Suelen A.M.; Rodrigues, Elton J. da R [Universidade Federal do Rio de Janeiro (NUCAT/PEQ/COPPE/UFRJ), RJ (Brazil). Laboratorio de Nanocompositos Polimericos

    2012-07-01

    Polyurethanes are important and versatile materials, mainly due to some of their properties, such as high resistance to abrasion and tearing, excellent absorption of mechanical shocks and good flexibility and elasticity. However, they have some drawbacks as well, such as low thermal stability and barrier properties. To overcome these disadvantages, various studies have been conducted involving organophilic polyurethane/montmorillonite nanocomposites. The investigation of the structure of polyurethane/clay nanocomposites has mainly been done by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this work, PU/clay nanocomposite films obtained by solution intercalation were studied. The nanocomposites were characterized by XRD and low-field nuclear magnetic resonance (LF-NMR). The LF-NMR measurements, with determination of the spin-lattice relaxation time of the hydrogen nucleus, supplied important information about the molecular dynamics of these nanocomposites. The X-ray diffraction measurements validated the results found by NMR. The thermal stability of the material was also determined by thermogravimetric analysis (TGA) under an inert atmosphere. A slight improvement in this stability was observed in the nanocomposite in comparison with polyurethane (author)

  20. Synthesis of rigid polyurethane foams from phosphorylated biopolyols.

    Science.gov (United States)

    de Haro, Juan Carlos; López-Pedrajas, Daniel; Pérez, Ángel; Rodríguez, Juan Francisco; Carmona, Manuel

    2017-08-18

    Renewable resources are playing a key role on the synthesis of biodegradable polyols. Moreover, the incorporation of covalently linked additives is increasing in importance in the polyurethane (PU) market. In this work, previously epoxidized grape seed oil and methyl oleate were transformed into phosphorylated biopolyols through an acid-catalyzed ring-opening hydrolysis in the presence of H 3 PO 4 . The formation of phosphate polyesters was confirmed by FT-IR and 31 P-NMR. However, the synthesis of a high-quality PU rigid foam was not possible using exclusively these polyols attending to their low hydroxyl value. In that way, different rigid PU foams were prepared from the phosphorylated biopolyols and the commercial polyol Alcupol R4520. It was observed that phosphorylated biopolyols can be incorporated up to a 57 wt.% in the PU synthesis without significant structural changes with respect to the commercial foam. Finally, thermogravimetric and EDAX analyses revealed an improvement of thermal stability by the formation of a protective phosphorocarbonaceous char layer.

  1. Mixed Field Modification of Thermally Cured Castor Oil Based Polyurethanes

    International Nuclear Information System (INIS)

    Mortley, A.

    2006-01-01

    Thermally cured polyurethanes were prepared from castor oil and hexamethylene diisocyanatee (HMDI). Due to the long aliphatic chain of the castor oil component of polyurethane, thermal curing of castor oil based polyurethane (COPU) is limited by increasing polymer viscosity. To enhance further crosslinking, COPUs were subjected to a range of accumulated doses (0.0-3.0 MGy) produced by the mixed ionizing field of the SLOWPOKE-2 research reactor. The physico-mechanical properties of COPU, unirradiated and irradiated, were characterized by mechanical tests. Increased bond formation resulting from radiation-induced crosslinking was confirmed by favorable increases in mechanical properties and by solid-state 13 C -NMR and FTIR spectra

  2. Applicability of liquid radiopaque polyurethane for transcatheter embolization

    International Nuclear Information System (INIS)

    Novak, D.; Wieners, H.; Rueckner, R.

    1983-01-01

    Polyurethane Bayer was tested as an occlusive agent for experimental embolization in postmortem and postnephrectomy kidneys which served as a tumor model. Coaxial and balloon catheters were used for the embolization. To make polyurethane radiopaque, the material was labeled with different water-soluble, oily and solid contrast agents. Best results were achieved with oily contrast materials, e.g., Pantopaque. We found that polyurethane can easily be injected during a predetermined working time of 8-10 min. The embolization results in a complete, permanent, and homogeneous occlusion of the proximal arterial branches and small peripheral vessels. (orig.)

  3. Study of the morphology exhibited by linear segmented polyurethanes

    International Nuclear Information System (INIS)

    Pereira, I.M.; Orefice, R.L.

    2009-01-01

    Five series of segmented polyurethanes with different hard segment content were prepared by the prepolymer mixing method. The nano-morphology of the obtained polyurethanes and their microphase separation were investigated by infrared spectroscopy, modulated differential scanning calorimetry and small-angle X-ray scattering. Although highly hydrogen bonded hard segments were formed, high hard segment contents promoted phase mixture and decreased the chain mobility, decreasing the hard segment domain precipitation and the soft segments crystallization. The applied techniques were able to show that the hard-segment content and the hard-segment interactions were the two controlling factors for determining the structure of segmented polyurethanes. (author)

  4. The influence of chain extender on properties of polyurethane-based phase change materials modified with graphene

    International Nuclear Information System (INIS)

    Pielichowska, Kinga; Nowak, Michał; Szatkowski, Piotr; Macherzyńska, Beata

    2016-01-01

    Highlights: • Polyurethane/graphene composites with solid–solid phase transition were obtained. • PEG incorporated as a soft segment acts as PCM with high heat of phase transition. • The influence of chain extender on PU PCMs properties was investigated. • Graphene introduction caused an increase in thermal stability and conductivity. - Abstract: In this paper polyurethane-based phase change materials (PCMs) modified with graphene for thermal energy storage were obtained in situ using a one-step bulk polymerization method. Polyurethanes (PUs) have been synthesized with 1,4-butanediol as a chain extender or without a chain extender. FTIR-ATR, DSC, TGA, SEM, OM and ultrasonic techniques were used for characterization of the obtained composites containing up to 4 wt.% of graphene. FTIR-ATR analysis confirmed PU structure and proved that there was no chemical reaction between polyurethane and graphene. The highest heat of phase transition and crystallinity were found for PU system synthesized without the chain extender and modified with 1.0 wt.% of graphene. Microscopic observation results indicated spherulite structures typical for poly(ethylene glycol) (PEG) which was used to form soft segments, with regions of lamellar crystal bundles radiating from the center of a spherulite. Thermal cycling tests were done by 50 and 100 heating/cooling cyclings in air and nitrogen atmosphere for verification of the thermal reliability and chemical stability – it has been found the heat of phase transition was generally not diminished. Importantly, the thermal conductivity of the PCMs was improved after modification with graphene. Generally, PUPEG without chain extender exhibited higher heat of phase transition, higher thermal stability and better thermal reliability.

  5. Effect of silica nanoparticles on polyurethane foaming process and foam properties

    International Nuclear Information System (INIS)

    Francés, A B; Bañón, M V Navarro

    2014-01-01

    Flexible polyurethane foams (FPUF) are commonly used as cushioning material in upholstered products made on several industrial sectors: furniture, automotive seating, bedding, etc. Polyurethane is a high molecular weight polymer based on the reaction between a hydroxyl group (polyol) and isocyanate. The density, flowability, compressive, tensile or shearing strength, the thermal and dimensional stability, combustibility, and other properties can be adjusted by the addition of several additives. Nanomaterials offer a wide range of possibilities to obtain nanocomposites with specific properties. The combination of FPUF with silica nanoparticles could develop nanocomposite materials with unique properties: improved mechanical and thermal properties, gas permeability, and fire retardancy. However, as silica particles are at least partially surface-terminated with Si-OH groups, it was suspected that the silica could interfere in the reaction of poyurethane formation.The objective of this study was to investigate the enhancement of thermal and mechanical properties of FPUF by the incorporation of different types of silica and determining the influence thereof during the foaming process. Flexible polyurethane foams with different loading mass fraction of silica nanoparticles (0-1% wt) and different types of silica (non treated and modified silica) were synthesized. PU/SiO 2 nanocomposites were characterized by FTIR spectroscopy, TGA, and measurements of apparent density, resilience and determination of compression set. Addition of silica nanoparticles influences negatively in the density and compression set of the foams. However, resilience and thermal stability of the foams are improved. Silica nanoparticles do not affect to the chemical structure of the foams although they interfere in the blowing reaction

  6. Gamma-ray irradiation, autoclave and ethylene oxide sterilization to thermosetting polyurethane: sterilization to polyurethane

    International Nuclear Information System (INIS)

    Hirata, Noriko; Matsumoto, Ken-Ichi; Inishita, Takashi; Takenaka, Yoshinori; Suma, Yasunori; Shintani, Hideharu; National Inst. of Health Sciences, Tokyo

    1995-01-01

    Thermosetting polyurethane (PU) is widely used in a large variety of medical devices. 4,4'-methylenedianiline (MDA) was produced from PU by sterilization and it was studied for the relationship between urethane components or polymer characteristics and formation of MDA upon sterilization, using the commercially available dialyzers fabricated with different combination of isocyanate and polyol. We confirmed that the molecular-weight of polyol influenced the production of MDA upon sterilization. (author)

  7. Thermal insulating materials consisting of polyurethane rigid foam. Production - application - properties. 2. ed.; Waermedaemmstoffe aus Polyurethan-Hartschaum. Herstellung - Anwendung - Eigenschaften

    Energy Technology Data Exchange (ETDEWEB)

    Endres, Edmund; Kleser, Joachim

    2008-02-15

    Using rigid polyurethane (PU) / polyisocyanurate (PIR) foam as a thermal insulation material enables a conservation of resources and energy conservation. Environmentally harmful emissions significantly are reduced. Under this aspect, the authors of the contribution report on the production, application, technical and physical properties of rigid polyurethane foams. Sustainable construction with rigid polyurethane foam, quality assurance and product certification are further topics of this paper.

  8. Mixed field radiation modification of polyurethanes based on castor oil

    International Nuclear Information System (INIS)

    Mortley, A.; Bonin, H.W.; Bui, V.T.

    2006-01-01

    Polyurethane is among the polymers and polymer-based composite materials being investigated at the Royal Military College of Canada for the fabrication of leak-tight containers for the long-term disposal of radioactive waste. Due to the long aliphatic chain of the castor oil component of polyurethane, thermal curing of castor oil based polyurethane (COPU) is limited by increasing polymer viscosity. To enhance further crosslinking, COPUs were subjected to a range of doses (0.0 - 3.0 MGy) produced by the mixed ionizing radiation field of a SLOWPOKE-2 research nuclear reactor. The tensile mechanical properties of castor oil based polyurethanes (COPU), unirradiated and irradiated, were characterized by mechanical tensile tests. Increases in mechanical strength due to radiation-induced crosslinking and limitations of thermal curing were confirmed by tensile tests and changing 13 C-NMR and FTIR spectra. (author)

  9. The effect of radiosterilization on surface properties of polyurethane film

    International Nuclear Information System (INIS)

    Sheikh, N.

    2003-01-01

    In this paper the effect of sterilization method by gamma-ray on structure and cytotoxicity of polyurethane film surface has been investigated. For this purpose reactive urethan prepolymer was synthesized by the reaction between Tdi with a mixture of Peg and castro oil (50/50, w/w). The cured prepolymer films were prepared due to the reaction of reactive prepolymer with air moister under ambient conditions. The polyurethane films were sterilized by gamma-ray (25 kGy). The surface of sterilized polyurethane film was observed by Sem and compared to that of the unsterilized film. Also, the in vitro interaction of fibroblast L 929 cells and sterilized polyurethane film was evaluated. Results showed no signs of cell toxicity

  10. The effect of radiosterilization on cytotoxicity of polyurethane film

    International Nuclear Information System (INIS)

    Sheikh, N.

    2003-01-01

    Nowadays a sequence of tests for evaluation of sterilized biomaterial includes an initial set of tests in vitro, both biological (cell culture) and non-biological (mechanical tests). In this paper the cytotoxicity of a sterilized polyurethane film, in order to use as biomaterial, has been investigated. For this purpose NCO-terminated urethane prepolymer in medical quality was synthesized without ingredients beside monomers (polyethylene glycol/castor oil and toluene diisocyanate). The cured prepolymer films were prepared under ambient conditions due to the reaction of free NCO-groups of prepolymer with air moisture. The polyurethane films were sterilized by gamma-ray (25 kGy). The surface structure of sterilized polyurethane film was observed by SEM and compared to that of the unsterilized film. Also, the in vitro interaction of fibroblast cells and sterilized polyurethane film in culture medium containing serum was evaluated in comparison with control samples. Results showed no signs of cell toxicity

  11. Characterization of synthesized polyurethane/montmorillonite nanocomposites foams

    International Nuclear Information System (INIS)

    Ansari, Farahnaz; Njuguna, James; Sachse, Sophia; Kavosh, Masoud; Michalowski, S; Pielichowski, Krzysztof

    2014-01-01

    Nanophased hybrid composites based on polyurethane/montmorillonite (PU/MMT) have been fabricated. The nanocomposite which was formed by the addition of a polyol premix with 4,4'-diphenylmethane diisocyanate to obtain nanophased polyurethane foams which were then used for fabrication of nanocomposite panels has been shown to have raised strength, stiffness and thermal insulation properties. The nanophased polyurethane foam was characterized by means of scanning electron microscope (SEM), transmission electron microscope (TEM) measurements and X-ray diffraction (XRD). TEM and SEM analysis indicated that nanophased particles are dispersed homogeneously in the polyurethane matrix on the nanometer scale indicating that PU/MMT is an intercalated nanocomposite with a 2-3 nm nanolayer thickness

  12. Mixed field radiation modification of polyurethanes based on castor oil

    Energy Technology Data Exchange (ETDEWEB)

    Mortley, A.; Bonin, H.W.; Bui, V.T. [Royal Military College of Canada, Dept. of Chemistry and Chemical Engineering, Kingston, Ontario (Canada)]. E-mail: aba.mortley@rmc.ca

    2006-07-01

    Polyurethane is among the polymers and polymer-based composite materials being investigated at the Royal Military College of Canada for the fabrication of leak-tight containers for the long-term disposal of radioactive waste. Due to the long aliphatic chain of the castor oil component of polyurethane, thermal curing of castor oil based polyurethane (COPU) is limited by increasing polymer viscosity. To enhance further crosslinking, COPUs were subjected to a range of doses (0.0 - 3.0 MGy) produced by the mixed ionizing radiation field of a SLOWPOKE-2 research nuclear reactor. The tensile mechanical properties of castor oil based polyurethanes (COPU), unirradiated and irradiated, were characterized by mechanical tensile tests. Increases in mechanical strength due to radiation-induced crosslinking and limitations of thermal curing were confirmed by tensile tests and changing {sup 13}C-NMR and FTIR spectra. (author)

  13. Surface coated polyurethane with improved bioactivity and cytocompatability

    CSIR Research Space (South Africa)

    Chetty, AS

    2006-02-01

    Full Text Available Polyurethane (PU) may be suitable for various implant applications; however, it lacks bioactivity. Bioactivity allows for direct tissue attachment at the bio- interface, enabling implant fixation while preventing fibrous encapsulation. To impart...

  14. Nano-engineered polyurethane resin-modified concrete.

    Science.gov (United States)

    2014-04-01

    The goal of the proposed work is to investigate the application of nano-engineered polyurethane (NEPU) emulsions for latex modified : concrete (LMC). NEPU emulsions are non-toxic, environment friendly, durable over a wide temperature range, provide b...

  15. Soy-based UV resistant polyurethane pultruded composites.

    Science.gov (United States)

    2012-02-01

    Aliphatic polyurethane (PU) nanocomposites were synthesized using organically modified nanoclays. X-Ray diffraction results : confirmed good exfoliation of nanoclay particles in the PU resin system. With the addition of just 1% of nanoclay in the bas...

  16. Influence of polyols on properties of bio-based polyurethanes

    Indian Academy of Sciences (India)

    resources for the preparation of polyols required for the polyurethane industry. Among the vegetable oils, cardanol a meta-substituted phenol obtained (Kumar et al 2002) from ... High ortho-multinuclear cardanol–formaldehyde resin was.

  17. Experimental Investigation of Polyurethane Camouflage Coating Using Dynamic Mechanical Analysis

    National Research Council Canada - National Science Library

    Crawford, Dawn

    1999-01-01

    .... The current polyurethane solvent-based (SOL) formulation, used as a chemical-agent-resistant camouflage top coat on all military tactical vehicles, was investigated, along with newly developed water-reducible (WR...

  18. Fast-Responding Bio-Based Shape Memory Thermoplastic Polyurethanes.

    Science.gov (United States)

    Petrović, Zoran S; Milić, Jelena; Zhang, Fan; Ilavsky, Jan

    2017-07-14

    Novel fast response shape-memory polyurethanes were prepared from bio-based polyols, diphenyl methane diisocyanate and butane diol for the first time. The bio-based polyester polyols were synthesized from 9-hydroxynonanoic acid, a product obtained by ozonolysis of fatty acids extracted from soy oil and castor oil. The morphology of polyurethanes was investigated by synchrotron ultra-small angle X-ray scattering, which revealed the inter-domain spacing between the hard and soft phases, the degree of phase separation, and the level of intermixing between the hard and soft phases. We also conducted thorough investigations of the thermal, mechanical, and dielectric properties of the polyurethanes, and found that high crystallization rate of the soft segment gives these polyurethanes unique properties suitable for shape-memory applications, such as adjustable transition temperatures, high degree of elastic elongations, and good mechanical strength. These materials are also potentially biodegradable and biocompatible, therefore suitable for biomedical and environmental applications.

  19. Feeding reduces waterborne Cu bioaccumulation in a marine rabbitfish Siganus oramin

    International Nuclear Information System (INIS)

    Guo, Zhiqiang; Zhang, Wei; Du, Sen; Zhou, Yanyan; Gao, Na; Zhang, Li; Green, Iain

    2016-01-01

    Waterborne metal uptake has been extensively studied and dietary metal assimilation is increasingly recognized in fish, whilst the interaction between the two uptake routes is largely overlooked. This study compared the waterborne Cu bioaccumulation ("6"5Cu as tracer) in a juvenile rabbitfish at different feeding regimes (starvation (SG), feeding normal diet (NDG) or diet supplemented with extra Cu (DCG)) to test the hypothesis that feeding can influence waterborne metal uptake in marine fish. NDG and DCG diet was fed as a single meal and then all fish were exposed to waterborne "6"5Cu for 48 h, during which the time course sampling was conducted to determine "6"5Cu bioaccumulation, chyme flow and dietary Cu assimilation. The results revealed that SG fish accumulated the highest "6"5Cu, followed by NDG (61% of SG), whilst DCG fish accumulated the lowest "6"5Cu (34% of SG). These results suggested a protective effect of feeding against waterborne Cu bioaccumulation. This effect was most notable between 10 min and 16 h when there was chyme in gastrointestinal tract (GT). Dietary Cu assimilation mainly occurred before 16 h after feeding. Waterborne "6"5Cu influx rate in the GT was positively correlated with "6"5Cu contents of chyme in NDG, whereas it was largely negatively correlated with "6"5Cu contents of chyme in DCG. The waterborne Cu uptake in the GT was mainly influenced by the chyme flow and dietary Cu assimilation. Overall, our findings suggested that feeding has an important effect on waterborne metal uptake and that both the feeding status of the fish and the relative metal exposure through water and food should be considered in prediction of the metal bioaccumulation and biomonitoring programs. - Highlights: • Feeding shows a protective effect against waterborne Cu uptake in fish. • The elevated dietary Cu can greatly suppress the waterborne Cu uptake. • The presence of chyme reduces Cu uptake in the gastrointestinal tract. • Feeding status has

  20. Multifunctional composite material based on carbon-filled polyurethane

    International Nuclear Information System (INIS)

    Malinovskaya, T; Melentyev, S; Pavlov, S

    2015-01-01

    The research paper deals with the performance of composite resistive material heating coatings based on the polyurethane binder, filled with colloidal-graphite preparation C- 1, which can be used in structures of electric heaters. Frequency dependences of transmission and reflection coefficients, dielectric permeability of composite materials with the various content of carbon fillers (technical carbon, graphite) in polyurethane varnish in ranges of frequencies 26-40 GHz and 110-260 GHz are experimentally investigated. (paper)

  1. Antimicrobial polyurethane thermosets based on undecylenic acid: synthesis and evaluation

    OpenAIRE

    Cádiz, V.; Galià, M.; Ronda, J.C.; Lligadas, G.; Bordons, A.; Esteve-Zarzoso, B.; Lluch, C.

    2014-01-01

    10.1002/mabi.201400017 In the present study, plant oil-derived surface-modifiable polyurethane thermosets are presented. Polyol synthesis is carried out taking advantage of thiol-yne photopolymerization of undecylenic acid derivatives containing methyl ester or hydroxyl moieties. The prepared methyl ester-containing polyurethanes allow surface modification treatment to enhance their hydrophilicity and impart antimicrobial activity through the following two steps: i) grafting poly(propylen...

  2. Polyurethane Coatings Reinforced by Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    Diethelm Johannsmann

    2013-01-01

    Full Text Available The pencil hardness of a two-component polyurethane coating was improved by adding halloysite nanotubes to the recipe at a weight fraction of less than 10%. The pencil hardness was around F for the unfilled coating and increased to around 2H upon filling. It was important to silanize the surface of the filler in order to achieve good coupling to the matrix. Sonicating the sample during drying also improved the hardness. Scanning electron micrographs suggest that the nanotubes are always well immersed into the bulk of the film. With a thickness between 10 and 20 µm, the optical clarity was good enough to clearly read letters through the film. The films can be used in applications where transparency is required.

  3. Degradation characteristics of waste polyurethane by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Seok; Ahn, Sung Jun; Gwon Hui Jeong; Jeong, Sung In; Nho, Young Chang; Lim, Youn Mook [Research Division for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2017-06-15

    Polyurethane (PU) is a very popular polymer that is used in a variety of applications due to its good mechanical, thermal, and chemical properties. However, waste PU recycling has received significant attention due to environmental issues. The aim of this work was to investigate the degradation characteristics of waste PU to recycle. Degradation of waste PU was carried out using a radiation techniques. Waste PUs were exposed to a gamma {sup 60}Co sources. To verify degradation, the irradiated PUs were characterized using FT-IR, gel permeation chromatography (GPC), and their thermal/mechanical properties are reported. When the radiation dose was 500 kGy, the molecular weight of the waste PU drastically decreased. Also, the mechanical properties of waste PU were approximately 4 times lower than those of non-irradiated PU. This study has confirmed the possibility of making fine particle of waste PU for recycling through radiation degradation techniques.

  4. Polyurethane elastomers from morphology to mechanical aspects

    CERN Document Server

    Prisacariu, Cristina

    2011-01-01

    A comprehensive account of the physical / mechanical behaviour of polyurethanes (PU´s) elastomers, films and blends of variable crystallinity. Aspects covered include the elasticity and inelasticity of amorphous to crystalline PUs, in relation to their sensitivity to chemical and physical structure. A study is made of how aspects of the constitutive responses of PUs vary with composition: the polyaddition procedure, the hard segment, soft segment and chain extender (diols and diamines) are varied systematically in a large number of systems of model and novel crosslinked andthermoplastic PUs. Results will be related to: microstructural changes, on the basis of evidence from x-ray scattering (SAXS and WAXS), and also dynamic mechanical analyses (DMA), differential scanning calorimetry (DSC) and IR dichroism. Inelastic effects will be investigated also by including quantitative correlations between the magnitude of the Mullins effect and the fractional energy dissipation by hysteresis under cyclic straining, g...

  5. Biodegradation of polyurethane derived from castor oil

    Directory of Open Access Journals (Sweden)

    José M. Cangemi

    2008-09-01

    Full Text Available The aim of this research was to study the biodegradation of a polymer derived from castor oil, which is a renewable, natural material that is a practical alternative for the replacement of traditional polyurethane foams. Due to its molecular structure, which contains polyester segments derived from vegetable oil, the polymeric surface is susceptible to microorganism attack. This study tested the biological degrading agent that was in contact with the microorganisms resulting from microbiological grease degrading agents, when foam was inoculated. Solid-media agar-plate tests were conducted for their potential to evaluate the biodegradation of polymeric particles by specific strains of microorganisms during 216 hours. The growth rate was defined. This technique provides a way of distinguishing the degradation abilities of microorganisms from the degradability of materials.

  6. Engineering Performance of Polyurethane Bonded Aggregates

    Directory of Open Access Journals (Sweden)

    Haimin WU

    2017-08-01

    Full Text Available In this paper the engineering performance of polyurethane (PUR bonded aggregate were studied. The engineering performance, including compressive and flexural mechanical properties, void ratio, and coefficient of permeability were determined through laboratory tests. Moreover, the effects of two different curing conditions on the compressive strength properties of a PUR bonded aggregate were also evaluated. The compressive strengths of PUR bonded aggregates were found to be lower than that of conventional porous concrete, which is a commonly used cushion material. However, experimental results indicated a higher void ratio and coefficient of permeability, lower elasticity modulus, better toughness, and stronger adaptability to flexural deformation compared to porous concrete. Consequently, PUR bonded aggregate is a better solution than porous concrete when used as the cushion material of a geomembrane surface barrier for a high rock-fill dam.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.15798

  7. Synthesis and properties of aqueous polyurethane dispersions: Influence of molecular weight of polyethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Mumtaz, Fatima; Zuber, Mohammad; Zia, Khalid Mahmood [Government College University, Faisalabad (Pakistan); Jamil, Tahir [University of the Punjab, Lahore (Pakistan); Hussain, Rizwan [National Engineering and Scientific Commission (NESCOM), Islamabad (Pakistan)

    2013-12-15

    Aqueous polyurethane dispersions (PUDs) have recently emerged as important alternatives to their solvent-based counterparts for various applications due to increasing health and environmental awareness. A series of aqueous polyurethane dispersions containing carboxylate anion as hydrophilic pendant groups were synthesized through step growth polymerization reaction using hexamethylene diisocyanate (HDI), 1,4-butanediol (1,4-BDO), dimethylol propionic acid (DMPA) and polyethylene glycol (PEG) of different molecular weight. Effect of PEG molecular weight was investigated on molecular structure, contact angle measurement, and physical and adhesive properties of PU emulsions. Fourier transform infrared spectroscopy (FT-IR) was used to check the completion of polymerization reaction. Contact angle measurement indicated that the hydrophilicity of polymer increases by increasing molecular weight of PEG with a corresponding decrease in contact angle. Results of T-peel test showed a decrease in peel strength by increasing molecular weight of PEG. Moreover, solid contents%, drying time and storage stability suggested fast drying properties and greater stability of aqueous PU dispersions.

  8. New polyurethane/docosane microcapsules as phase-change materials for thermal energy storage.

    Science.gov (United States)

    Felix De Castro, Paula; Shchukin, Dmitry G

    2015-07-27

    Polyurethane microcapsules were prepared by mini-emulsion interfacial polymerization for encapsulation of phase-change material (n-docosane) for energy storage. Three steps were followed with the aim to optimize synthesis conditions of the microcapsules. First, polyurethane microcapsules based on silicone oil core as an inert template with different silicone oil/poly(ethylene glycol)/4,4'-diphenylmethane diisocyanate wt % ratio were synthesized. The surface morphology of the capsules was analyzed by scanning electronic microscopy (SEM) and the chemical nature of the shell was monitored by Fourier transform infrared spectroscopy (FT-IR). Capsules with the silicone oil/poly(ethylene glycol)/4,4'-diphenylmethane diisocyanate 10/20/20 wt % ratio showed the best morphological features and shell stability with average particle size about 4 μm, and were selected for the microencapsulation of the n-docosane. In the second stage, half of the composition of silicone oil was replaced with n-docosane and, finally, the whole silicone oil content was replaced with docosane following the same synthetic procedure used for silicone oil containing capsules. Thermal and cycling stability of the capsules were investigated by thermal gravimetric analysis (TGA) and the phase-change behavior was evaluated by differential scanning calorimetry (DSC). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Bio-based hyperbranched thermosetting polyurethane/triethanolamine functionalized multi-walled carbon nanotube nanocomposites as shape memory materials.

    Science.gov (United States)

    Kalita, Hemjyoti; Karak, Niranjan

    2014-07-01

    Here, bio-based shape memory polymers have generated immense interest in recent times. Here, Bio-based hyperbranched polyurethane/triethanolamine functionalized multi-walled carbon nanotube (TEA-f-MWCNT) nanocomposites were prepared by in-situ pre-polymerization technique. The Fourier transform infrared spectroscopy and the transmission electron microscopic studies showed the strong interfacial adhesion and the homogeneous distribution of TEA-f-MWCNT in the polyurethane matrix. The prepared epoxy cured thermosetting nanocomposites exhibited enhanced tensile strength (6.5-34.5 MPa), scratch hardness (3.0-7.5 kg) and thermal stability (241-288 degrees C). The nanocomposites showed excellent shape fixity and shape recovery. The shape recovery time decreases (24-10 s) with the increase of TEA-f-MWCNT content in the nanocomposites. Thus the studied nanocomposites have potential to be used as advanced shape memory materials.

  10. Preparation and Characterization of Fluorinated Hydrophobic UV-Crosslinkable Thiol-Ene Polyurethane Coatings

    Directory of Open Access Journals (Sweden)

    Wenjing Xia

    2017-08-01

    Full Text Available The polyurethane prepolymer terminated with a double bond was synthesized using isophorone diisocyanate (IPDI, hydroxyl terminated polybutadiene (HTPB, 1,4-butanediol (BDO, and 2-hydroxyethyl acrylate (HEA. Then, a series of innovative UV-curable polyurethane coatings were prepared by blending ene-terminated polyurethane, fluoroacrylate monomer, and multifunctional thiol crosslinker upon UV exposure. The incorporation of fluoroacrylate monomer and multifunctional thiols into polyurethane coatings significantly enhanced the hydrophobic property, mechanical property, pencil hardness, and glossiness of the polyurethane coatings. This method of preparing UV crosslinkable, hydrophobic polyurethane coatings based on thiol-ene chemistry exhibited numerous advantages over other UV photocuring systems.

  11. Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells☆

    Science.gov (United States)

    Nalluri, Sandeep M.; Krishnan, G. Rajesh; Cheah, Calvin; Arzumand, Ayesha; Yuan, Yuan; Richardson, Caley A.; Yang, Shuying; Sarkar, Debanjan

    2016-01-01

    Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell–matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell–cell and cell–matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell–matrix interaction, and cell–cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration. PMID:26046282

  12. Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells.

    Science.gov (United States)

    Nalluri, Sandeep M; Krishnan, G Rajesh; Cheah, Calvin; Arzumand, Ayesha; Yuan, Yuan; Richardson, Caley A; Yang, Shuying; Sarkar, Debanjan

    2015-09-01

    Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell-matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell-cell and cell-matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell-matrix interaction, and cell-cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. 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.

  14. pH dependence of the properties of waterborne pressure-sensitive adhesives containing acrylic acid.

    Science.gov (United States)

    Wang, Tao; Canetta, Elisabetta; Weerakkody, Tecla G; Keddie, Joseph L; Rivas, Urko

    2009-03-01

    Polymer colloids are often copolymerized with acrylic acid monomers in order to impart colloidal stability. Here, the effects of the pH on the nanoscale and macroscopic adhesive properties of waterborne poly(butyl acrylate-co-acrylic acid) films are reported. In films cast from acidic colloidal dispersions, hydrogen bonding between carboxylic acid groups dominates the particle-particle interactions, whereas ionic dipolar interactions are dominant in films cast from basic dispersions. Force spectroscopy using an atomic force microscope and macroscale mechanical measurements show that latex films with hydrogen-bonding interactions have lower elastic moduli and are more deformable. They yield higher adhesion energies. On the other hand, in basic latex, ionic dipolar interactions increase the moduli of the dried films. These materials are stiffer and less deformable and, consequently, exhibit lower adhesion energies. The rate of water loss from acidic latex is slower, perhaps because of hydrogen bonding with the water. Therefore, although acid latex offers greater adhesion, there is a limitation in the film formation.

  15. [Waterborne outbreak of gastroenteritis transmitted through the public water supply].

    Science.gov (United States)

    Godoy, P; Borrull, C; Palà, M; Caubet, I; Bach, P; Nuín, C; Espinet, L; Torres, J; Mirada, G

    2003-01-01

    The chlorination of public water supplies has led researchers to largely discard drinking water as a potential source of gastroenteritis outbreaks. The aim of this study was to investigate an outbreak of waterborne disease associated with drinking water from public supplies. A historical cohort study was carried out following notification of a gastroenteritis outbreak in Baqueira (Valle de Arán, Spain). We used systematic sampling to select 87 individuals staying at hotels and 67 staying in apartments in the target area. Information was gathered on four factors (consumption of water from the public water supply, sandwiches, water and food in the ski resorts) as well as on symptoms. We assessed residual chlorine in drinking water, analyzed samples of drinking water, and studied stool cultures from 4 patients. The risk associated with each water source and food type was assessed by means of relative risk (RR) and 95% confidence intervals (CI). The overall attack rate was 51.0% (76/149). The main symptoms were diarrhea 87.5%, abdominal pain 80.0%, nausea 50.7%, vomiting 30.3%, and fever 27.0%. The only factor associated with a statistically significant risk of disease was consumption of drinking water (RR = 11.0; 95% CI, 1.6-74.7). No residual chlorine was detected in the drinking water, which was judged acceptable. A problem associated with the location of the chlorinator was observed and corrected. We also recommended an increase in chlorine levels, which was followed by a reduction in the number of cases. The results of stool cultures of the four patients were negative for enterobacteria. This study highlights the potential importance of waterborne outbreaks of gastroenteritis transmitted through drinking water considered acceptable and suggests the need to improve microbiological research into these outbreaks (viruses and protozoa detection).

  16. Knowledge Mapping for Climate Change and Food- and Waterborne Diseases

    Science.gov (United States)

    Semenza, Jan C.; Höuser, Christoph; Herbst, Susanne; Rechenburg, Andrea; Suk, Jonathan E.; Frechen, Tobias; Kistemann, Thomas

    2011-01-01

    The authors extracted from the PubMed and ScienceDirect bibliographic databases all articles published between 1998 and 2009 that were relevant to climate change and food- and waterborne diseases. Any material within each article that provided information about a relevant pathogen and its relationship with climate and climate change was summarized as a key fact, entered into a relational knowledge base, and tagged with the terminology (predefined terms) used in the field. These terms were organized, quantified, and mapped according to predefined hierarchical categories. For noncholera Vibrio sp. and Cryptosporidium sp., data on climatic and environmental influences (52% and 49% of the total number of key facts, respectively) pertained to specific weather phenomena (as opposed to climate change phenomena) and environmental determinants, whereas information on the potential effects of food-related determinants that might be related to climate or climate change were virtually absent. This proportion was lower for the other pathogens studied (Campylobacter sp. 40%, Salmonella sp. 27%, Norovirus 25%, Listeria sp. 8%), but they all displayed a distinct concentration of information on general food-and water-related determinants or effects, albeit with little detail. Almost no information was available concerning the potential effects of changes in climatic variables on the pathogens evaluated, such as changes in air or water temperature, precipitation, humidity, UV radiation, wind, cloud coverage, sunshine hours, or seasonality. Frequency profiles revealed an abundance of data on weather and food-specific determinants, but also exposed extensive data deficiencies, particularly with regard to the potential effects of climate change on the pathogens evaluated. A reprioritization of public health research is warranted to ensure that funding is dedicated to explicitly studying the effects of changes in climate variables on food- and waterborne diseases. PMID:24771989

  17. Cell reprogramming by 3D bioprinting of human fibroblasts in polyurethane hydrogel for fabrication of neural-like constructs.

    Science.gov (United States)

    Ho, Lin; Hsu, Shan-Hui

    2018-04-01

    3D bioprinting is a technique which enables the direct printing of biodegradable materials with cells into 3D tissue. So far there is no cell reprogramming in situ performed with the 3D bioprinting process. Forkhead box D3 (FoxD3) is a transcription factor and neural crest marker, which was reported to reprogram human fibroblasts into neural crest stem-like cells. In this study, we synthesized a new biodegradable thermo-responsive waterborne polyurethane (PU) gel as a bioink. FoxD3 plasmids and human fibroblasts were co-extruded with the PU hydrogel through the syringe needle tip for cell reprogramming. The rheological properties of the PU hydrogel including the modulus, gelation time, and shear thinning were optimized for the transfection effect of FoxD3 in situ. The corresponding shear rate and shear stress were examined. Results showed that human fibroblasts could be reprogrammed into neural crest stem-like cells with high cell viability during the extrusion process under an average shear stress ∼190 Pa. We further translated the method to the extrusion-based 3D bioprinting, and demonstrated that human fibroblasts co-printed with FoxD3 in the thermo-responsive PU hydrogel could be reprogrammed and differentiated into a neural-tissue like construct at 14 days after induction. The neural-like tissue construct produced by 3D bioprinting from human fibroblasts may be applied to personalized drug screening or neuroregeneration. There is no study so far on cell reprogramming in situ with 3D bioprinting. In this manuscript, a new thermoresponsive polyurethane bioink was developed and employed to deliver FoxD3 plasmid into human fibroblasts by the extrusion-based bioprinting. When the polyurethane gel was extruded through the syringe tip, the shear stress generated may have caused the transient membrane permeability for transfection. The shear stress was optimized for transfection in situ by 3D bioprinting. We demonstrated that human fibroblasts could be

  18. Sanitation and risks of waterborne diseases in Aholouyèmè in the ...

    African Journals Online (AJOL)

    SARAH

    2016-04-30

    Apr 30, 2016 ... 2 Laboratory Pierre PAGNEY: Climate, Water, Ecosystems and ... Objective: The present study aims to analyze the risk of diseases related to .... Figure 3: Monthly rhythm of rains and waterborne pathologies from 2010 to 2013.

  19. Excel file of salivary antibody analysis for Boqueron Beach study, Puerto Rico for six waterborne pathogens.

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset is the raw Luminex antibody responses to six common waterborne pathogens reported in MFI (Median Fluorescence Intensity) units. This dataset is...

  20. Quantifying the impact of climate change on enteric waterborne pathogen concentrations in surface water

    NARCIS (Netherlands)

    Hofstra, N.

    2011-01-01

    Climate change, among other factors, will impact waterborne pathogen concentrations in surface water worldwide, possibly increasing the risk of diseases caused by these pathogens. So far, the impacts are only determined qualitatively and thorough quantitative estimates of future pathogen

  1. Evaluation and specification of high build and special use waterborne pavement markings.

    Science.gov (United States)

    2014-01-01

    High build waterborne traffic paints and highly retro-reflective elements were applied at various locations to evaluate their : practicality for use by NYSDOT Maintenance forces. In addition, highly reflective elements were applied within grooved in ...

  2. Multiplex PCR detection of waterborne intestinal protozoa: microsporidia, Cyclospora, and Cryptosporidium.

    Science.gov (United States)

    Lee, Seung-Hyun; Joung, Migyo; Yoon, Sejoung; Choi, Kyoungjin; Park, Woo-Yoon; Yu, Jae-Ran

    2010-12-01

    Recently, emerging waterborne protozoa, such as microsporidia, Cyclospora, and Cryptosporidium, have become a challenge to human health worldwide. Rapid, simple, and economical detection methods for these major waterborne protozoa in environmental and clinical samples are necessary to control infection and improve public health. In the present study, we developed a multiplex PCR test that is able to detect all these 3 major waterborne protozoa at the same time. Detection limits of the multiplex PCR method ranged from 10(1) to 10(2) oocysts or spores. The primers for microsporidia or Cryptosporidium used in this study can detect both Enterocytozoon bieneusi and Encephalitozoon intestinalis, or both Cryptosporidium hominis and Cryptosporidium parvum, respectively. Restriction enzyme digestion of PCR products with BsaBI or BsiEI makes it possible to distinguish the 2 species of microsporidia or Cryptosporidium, respectively. This simple, rapid, and cost-effective multiplex PCR method will be useful for detecting outbreaks or sporadic cases of waterborne protozoa infections.

  3. Effect of nitrogen-doped carbon dots on the anticorrosion properties of waterborne epoxy coatings

    Science.gov (United States)

    Ren, Siming; Cui, Mingjun; Zhao, Haichao; Wang, Liping

    2018-06-01

    In this work, nitrogen-doped carbon dots (NCDs) are prepared by solvothermal method and the effect of NCDs on the anticorrosion property of waterborne epoxy (EP) is investigated. Scanning probe microscopy results show that the size of the NCDs is about 4–6 nm. In addition, the anticorrosion property of NCD-incorporated waterborne epoxy coatings is investigated via electrochemical techniques and scanning electron microscopy. Electrochemical results demonstrate that the impedance modulus of 2.0% NCDs/EP is 364 times higher than that of blank EP after 800 h of immersion, indicating significant enhancement in the anticorrosion property of waterborne epoxy coating. The reason is that NCDs with lots of surface functional groups can connect with waterborne epoxy to suppress enlargement of the pores, and reduce the diffusion of oxygen in the coating, thus cutting off the connection between the substrate and oxygen, and delaying corrosion of the substrate.

  4. Copolymer adsorption and the effect on colloidal stability

    NARCIS (Netherlands)

    Bijsterbosch, H.D.

    1998-01-01

    The main aim of the work described in this thesis is to study the effect of different types of copolymers on the stability of aqueous oxide dispersions. Such dispersions are a major component in water-borne paints. In order to obtain a better insight in steric stabilisation we first investigated the

  5. IDENTIFICATION OF CFC AND HCFC SUBSTITUTES FOR BLOWING POLYURETHANE FOAM INSULATION PRODUCTS

    Science.gov (United States)

    The report gives results of a cooperative effort to identiry chlorofluorocarbons and hydrochlorofluorocarbon substitutes for blowing polyurethane foam insulation products. The substantial ongoing effort is identifying third-generation blowing agets for polyurethane foams to repla...

  6. Biobased composites from thermoplastic polyurethane elastomer and cross-linked acrylated-epoxidized soybean oil

    Science.gov (United States)

    Soybean oil is an important sustainable material. Crosslinked acrylated epoxidized soybean oil (AESO) is brittle without flexibility and the incorporation of thermoplastic polyurethane improves its toughness for industrial applications. The hydrophilic functional groups from both oil and polyurethan...

  7. SPECIFIC FEATURES OF OLIGOMERIC PRODUCT SOLIDIFICATION FROM POLYURETHANE WASTES AND THEIR PRACTICAL APPLICATION

    OpenAIRE

    V. Belyatsky; Yu. Kryvogus

    2012-01-01

    The paper considers a possibility to use secondary polyurethane obtained by  thermal depolymerization of wastes on the basis of cross-linked polyurethane (polyurethane adduct) and isocyanate. An effect of density dependence of the obtained polyurethane samples on nature and quantity of solvent has been revealed and it is significantly observed while using low-boiling solvents. The influence of adduct/solidification agent ratio on mechanical hardness of the obtained samples has been studied in...

  8. Preparation and Characterization of Fluorinated Hydrophobic UV-Crosslinkable Thiol-Ene Polyurethane Coatings

    OpenAIRE

    Wenjing Xia; Nianqing Zhu; Rongjie Hou; Wengui Zhong; Mingqing Chen

    2017-01-01

    The polyurethane prepolymer terminated with a double bond was synthesized using isophorone diisocyanate (IPDI), hydroxyl terminated polybutadiene (HTPB), 1,4-butanediol (BDO), and 2-hydroxyethyl acrylate (HEA). Then, a series of innovative UV-curable polyurethane coatings were prepared by blending ene-terminated polyurethane, fluoroacrylate monomer, and multifunctional thiol crosslinker upon UV exposure. The incorporation of fluoroacrylate monomer and multifunctional thiols into polyurethane ...

  9. Polyurethane Organosilicate Nanocomposites as Blood Compatible Coatings

    Directory of Open Access Journals (Sweden)

    Johnson H. Y. Chung

    2012-02-01

    Full Text Available Polymer clay nanocomposites (NCs show remarkable potential in the field of drug delivery due to their enhanced barrier properties. It is hypothesised that well dispersed clay particles within the polymer matrix create a tortuous pathway for diffusing therapeutic molecules, thereby resulting in more sustained release of the drug. As coatings for medical devices, these materials can simultaneously modulate drug release and improve the mechanical performance of an existing polymer system without introducing additional materials with new chemistries that can lead to regulatory concerns. In this study, polyurethane organosilicate nanocomposites (PUNCs coated onto stainless steel wires were evaluated for their feasibility as blood compatible coatings and as drug delivery systems. Heparin was selected as the model drug to examine the impact of silicate loading and modifier chain length in modulating release. Findings revealed that better dispersion was achieved from samples with lower clay loadings and longer alkyl chains. The blood compatibility of PUNCs as assessed by thrombin generation assays showed that the addition of silicate particles did not significantly decrease the thrombin generation lag time (TGT, p = 0.659 or the peak thrombin (p = 0.999 of polyurethane (PU. PUNC coatings fabricated in this research were not cytotoxic as examined by the cell growth inhibition assay and were uniformly intact, but had slightly higher growth inhibition compared to PU possibly due to the presence of organic modifiers (OM. The addition of heparin into PUNCs prolonged the TGT, indicating that heparin was still active after the coating process. Cumulative heparin release profiles showed that the majority of heparin released was from loosely attached residues on the surface of coils. The addition of heparin further prolonged the TGT as compared to coatings without added heparin, but a slight decrease in heparin activity was observed in the NCs

  10. Polyurethanes for potential use in transparent armour investigated using DSC and DMA

    NARCIS (Netherlands)

    Ekeren, P.J. van; Carton, E.P.

    2011-01-01

    A material combination that may be applied as transparent armour is glass-clad polyurethane. These are comprised of a relatively thin glass strike face and a relatively thick (transparent) polyurethane backing layer. Three transparent polyurethane samples were investigated using differential

  11. 40 CFR 721.8079 - Isophorone diisocyanate neopentyl glycol adipate polyurethane prepolymer.

    Science.gov (United States)

    2010-07-01

    ... glycol adipate polyurethane prepolymer. 721.8079 Section 721.8079 Protection of Environment ENVIRONMENTAL... adipate polyurethane prepolymer. (a) Chemical substance and significant new uses subject to reporting. (1... polyurethane prepolymer (PMN P-94-1743) is subject to reporting under this section for the significant new uses...

  12. Rheokinetics and effect of shear rate on the kinetics of linear polyurethane formation

    NARCIS (Netherlands)

    Navarchian, AH; Picchioni, F; Janssen, LPBM

    In this article, the rheokinetics of polyurethane formation and the influence of shear rate on its kinetics have been studied. Two different linear polyurethane systems with 0% and 100% hard segments are examined in a cone and plate rheometer. The isothermal increase of viscosity during polyurethane

  13. 40 CFR 63.1293 - Standards for slabstock flexible polyurethane foam production.

    Science.gov (United States)

    2010-07-01

    ... polyurethane foam production. 63.1293 Section 63.1293 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1293 Standards for slabstock flexible polyurethane foam production. Each owner or operator of a...

  14. 40 CFR 63.1300 - Standards for molded flexible polyurethane foam production.

    Science.gov (United States)

    2010-07-01

    ... polyurethane foam production. 63.1300 Section 63.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1300 Standards for molded flexible polyurethane foam production. Each owner or operator of a new...

  15. Unified Creep Plasticity Damage (UCPD) Model for Rigid Polyurethane Foams.

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, Michael K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lu, Wei-Yang [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Scherzinger, William M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hinnerichs, Terry D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lo, Chi S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-06-01

    Numerous experiments were performed to characterize the mechanical response of several different rigid polyurethane foams (FR3712, PMDI10, PMDI20, and TufFoam35) to large deformation. In these experiments, the effects of load path, loading rate, and temperature were investigated. Results from these experiments indicated that rigid polyurethane foams exhibit significant volumetric and deviatoric plasticity when they are compressed. Rigid polyurethane foams were also found to be very strain-rate and temperature dependent. These foams are also rather brittle and crack when loaded to small strains in tension or to larger strains in compression. Thus, a new Unified Creep Plasticity Damage (UCPD) model was developed and implemented into SIERRA with the name Foam Damage to describe the mechanical response of these foams to large deformation at a variety of temperatures and strain rates. This report includes a description of recent experiments and experimental findings. Next, development of a UCPD model for rigid, polyurethane foams is described. Selection of material parameters for a variety of rigid polyurethane foams is then discussed and finite element simulations with the new UCPD model are compared with experimental results to show behavior that can be captured with this model.

  16. Biodegradation of Polyester Polyurethane by Endophytic Fungi▿

    Science.gov (United States)

    Russell, Jonathan R.; Huang, Jeffrey; Anand, Pria; Kucera, Kaury; Sandoval, Amanda G.; Dantzler, Kathleen W.; Hickman, DaShawn; Jee, Justin; Kimovec, Farrah M.; Koppstein, David; Marks, Daniel H.; Mittermiller, Paul A.; Núñez, Salvador Joel; Santiago, Marina; Townes, Maria A.; Vishnevetsky, Michael; Williams, Neely E.; Vargas, Mario Percy Núñez; Boulanger, Lori-Ann; Bascom-Slack, Carol; Strobel, Scott A.

    2011-01-01

    Bioremediation is an important approach to waste reduction that relies on biological processes to break down a variety of pollutants. This is made possible by the vast metabolic diversity of the microbial world. To explore this diversity for the breakdown of plastic, we screened several dozen endophytic fungi for their ability to degrade the synthetic polymer polyester polyurethane (PUR). Several organisms demonstrated the ability to efficiently degrade PUR in both solid and liquid suspensions. Particularly robust activity was observed among several isolates in the genus Pestalotiopsis, although it was not a universal feature of this genus. Two Pestalotiopsis microspora isolates were uniquely able to grow on PUR as the sole carbon source under both aerobic and anaerobic conditions. Molecular characterization of this activity suggests that a serine hydrolase is responsible for degradation of PUR. The broad distribution of activity observed and the unprecedented case of anaerobic growth using PUR as the sole carbon source suggest that endophytes are a promising source of biodiversity from which to screen for metabolic properties useful for bioremediation. PMID:21764951

  17. Melt electrospinning of biodegradable polyurethane scaffolds

    Science.gov (United States)

    Karchin, Ari; Simonovsky, Felix I.; Ratner, Buddy D.; Sanders, Joan E.

    2014-01-01

    Electrospinning from the melt, in contrast to from solution, is an attractive tissue engineering scaffold manufacturing process as it allows for the formation of small diameter fibers while eliminating potentially cytotoxic solvents. Despite this, there is a dearth of literature on scaffold formation via melt electrospinning. This is likely due to the technical challenges related to the need for a well-controlled high temperature setup and the difficulty in developing an appropriate polymer. In this paper, a biodegradable and thermally stable polyurethane (PU) is described specifically for use in melt electrospinning. Polymer formulations of aliphatic PUs based on (CH2)4-content diisocyanates, polycaprolactone (PCL), 1,4-butanediamine and 1,4-butanediol (BD) were evaluated for utility in the melt electrospinning process. The final polymer formulation, a catalyst-purified PU based on 1,4-butane diisocyanate, PCL and BD in a 4/1/3 molar ratio with a weight-average molecular weight of about 40 kDa, yielded a nontoxic polymer that could be readily electrospun from the melt. Scaffolds electrospun from this polymer contained point bonds between fibers and mechanical properties analogous to many in vivo soft tissues. PMID:21640853

  18. Carboxylated Polyurethanes Containing Hyperbranched Polyester Soft Segments

    Directory of Open Access Journals (Sweden)

    Žigon, M.

    2006-09-01

    Full Text Available hyperbranched polyester soft segments (HB PU with functional carboxylic groups in order to enable the preparation of stable HB PU dispersions. Carboxylated hyperbranched polyurethanes were synthesized using a hyperbranched polyester based on 2,2-bis(methylolpropionic acid of the fourth pseudo-generation (Boltorn H40 and hexamethylene (HDI or isophorone diisocyanate (IPDI. The reactivity of hyperbranched polyester with HDI was lower than expected, possibly due to the presence of less reactive hydroxyl groups in the linear repeat units. A gel was formed at mole ratios rNCO/OH = 1:2 or 1:4. The synthesis of HB PU was performed with partly esterified hyperbranched polyester with lowered hydroxyl functionality. The carboxyl groups were incorporated in the HB PU backbone by reaction of residual hydroxyl groups with cis-1,2-cyclohexanedicarboxylic anhydride. HB PU aqueous dispersions were stable at least for two months, although their films were brittle. The tensile strength and Young's modulus of blends of linear and HB PU decreased with increasing content of HB PU whereas elongation at break remained nearly constant, which was explained in terms of looser chain packing due to more open tree-like hyperbranched structures.

  19. Shape memory of polyurethanes with silver nanoparticles

    International Nuclear Information System (INIS)

    Monteiro, Fernanda M.A.; Souza, Patterson P. de; Pereira, Iaci M.; Silva, Livio B.J. da; Orefice, Rodrigo L.

    2011-01-01

    Biodegradable polyurethane nano composites were synthesized in an aqueous environment and have their shape memory properties investigated. The matrix based in isopharane diisocyanate and poly(caprolactone diol) (Mn=1250, 2000 g.mol -1 ) was prepared by the prepolymer mixing process. The silver nanoparticles were produced by mixing AgNO 3 and tannic acid. The shape memory properties were measured using universal testing machine (DL3000, EMIC). The shape memory cycle consisted of the following steps: samples were deformed at room temperature; the mechanical constraints on the polymers were removed; samples were cooled down to 0 deg C and to retain the deformed shape; three processes were tested to recover the shape: (a) samples were heated up to 80 deg C in an oven, (b) immersed in pH 4.0 and (c) immersed in pH 7.0. To study the shape memory effect on the nanostructure, small angle X-ray scattering, wide angle X-ray scattering, infrared spectroscopy experiments were carried on. (author)

  20. Nano-Aramid Fiber Reinforced Polyurethane Foam

    Science.gov (United States)

    Semmes, Edmund B.; Frances, Arnold

    2008-01-01

    Closed cell polyurethane and, particularly, polyisocyanurate foams are a large family of flexible and rigid products the result of a reactive two part process wherein a urethane based polyol is combined with a foaming or "blowing" agent to create a cellular solid at room temperature. The ratio of reactive components, the constituency of the base materials, temperature, humidity, molding, pouring, spraying and many other processing techniques vary greatly. However, there is no known process for incorporating reinforcing fibers small enough to be integrally dispersed within the cell walls resulting in superior final products. The key differentiating aspect from the current state of art resides in the many processing technologies to be fully developed from the novel concept of milled nano pulp aramid fibers and their enabling entanglement capability fully enclosed within the cell walls of these closed cell urethane foams. The authors present the results of research and development of reinforced foam processing, equipment development, strength characteristics and the evolution of its many applications.

  1. Guanidine hydrochloride embedded polyurethanes as antimicrobial and absorptive wound dressing membranes with promising cytocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Sahraro, Maryam; Yeganeh, Hamid, E-mail: h.yeganeh@ippi.ac.ir; Sorayya, Marziyeh

    2016-02-01

    Preparation and assessments of novel absorptive wound dressing materials with efficient antimicrobial activity as well as very good cytocompatibility were described in this work. An amine terminated poly(hexamethylene guanidine hydrochloride) was prepared and used as curing agent of different epoxy-terminated polyurethane prepolymers. The structures of prepared materials were elucidated by evaluation of their {sup 1}H NMR and FTIR spectra. The recorded tensile strength of membranes confirmed the excellent dimensional stability of the film type dressings even at fully hydrated conditions. Therefore, these dressings could protect the wound bed from external forces during the healing period. The structurally optimized dressing membranes could preserve the desired moist environment over the wounded area, as a result of their balanced equilibrium, water absorption and water vapor transmission rate. Therefore, a very good condition for stimulation of self-healing of wound bed was attained. Also, owing to the presence of guanidine hydrochloride moieties embedded into the structure of dressings, efficient antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were detected. In vitro cytotoxicity assay of the prepared dressings revealed cytocompatibility of these materials against fibroblast cells. Therefore, they could support cell growth and proliferation at the wounded area. - Highlights: • New polyurethane wound dressings with guanidine hydrochloride based antimicrobials • Maintaining moist and warm wound environment for accelerating healing • Proper tensile strength of dressings even at fully hydrated state • Excellent biocompatibility index due to proper selection of starting materials.

  2. Spectroscopic Characteristics of Highly Selective Manganese Catalysis in Acqueous Polyurethane Systems

    Directory of Open Access Journals (Sweden)

    Miroljub Barac

    2006-11-01

    Full Text Available The latest investigations on producing more efficient catalytic aqueouspolyurethane systems are in the domain of metal complexes with mixed ligands. In ourprevious research works, the high selectivity for the isocyanate-hydroxyl reaction inaqueous polyurethane systems has been shown by the manganese(III mixed-ligandcomplexes. The two new complexes have been prepared with two acetylacetonate (acacligands and one maleate ligand and its hydroxylamine derivative of the general formula[Mn(C5H7O22L]. Their structures have been established by using the fundamental analyses,the FTIR and UV/VIS spectroscopic methods, as well as the magnetic measurements. Inorder to explain the different selectivity of the manganese(III mixed-ligand complexes, theUV and ESR spectroscopy have been employed to determine the kinetics of the complexes’decomposition. The thermal stability of the complexes has been determined by way of thedynamic TG method at the heating rate of 5°C⋅min-1 and at the temperature ranged 20-550°C. It suggests the decomposition of the complexes by loss of acid ligand. The main factor in the selective catalysis control in theaqueous polyurethane systems is the nature of the acid ligands and their impact on themanganese(II/manganese(III equilibrium.

  3. Preparation, characterization of microencapsulated ammonium polyphosphate and its flame retardancy in polyurethane composites

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Ming-Yuan; Chen, Wei-Jen [Department of Aviation Mechanical Engineering, China University of Science and Technology, Hsinchu County, 303, Taiwan (China); Kuan, Chen-Feng; Kuan, Hsu-Chiang [Department of Computer Application Engineering, Far East University, Tainan, 744, Taiwan (China); Yang, Jia-Ming [Green Flame Retardant Material Research Laboratory, Department of Safety, Health and Environmental Engineering, Hung-Kuang University, Taichung, 433, Taiwan (China); Chiang, Chin-Lung, E-mail: dragon@sunrise.hk.edu.tw [Green Flame Retardant Material Research Laboratory, Department of Safety, Health and Environmental Engineering, Hung-Kuang University, Taichung, 433, Taiwan (China)

    2016-04-15

    In this study, a novel microencapsulated flame retardant containing ammonium polyphosphate (APP) and an 4,4′-oxydianiline-formaldehyde (OF) resin as the core and shell material was synthesized using in situ polymerization technology. The structure and performance of OF microencapsulated APP (OFAPP) were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The thermal properties of OFAPP were systematically analyzed through thermogravimetric analysis. Flame retardancy tests, such as limiting oxygen index (LOI) and UL-94, were conducted to evaluate the effect of varying the composition of APP and OFAPP in silanol-terminated polyurethane (Si-PU) composites. The results indicated that the microencapsulation of APP with the OF resin resulted in improved hydrophobicity. The results also revealed that the flame retardancy of the Si-PU/OFAPP composite (LOI = 37%) was higher than that of the Si-PU/APP composite (LOI = 23%) at the same additive loading. - Highlights: • A novel microencapsulated flame retardant was synthesized using in situ polymerization technology. • The microencapsulation of ammonium polyphosphate with the polymer resin resulted in improved hydrophobicity. • Polyurethane composites have excellent thermal stability and flame retardance.

  4. SYNTHESIS, CHARACTERIZATION AND APPLICATION OF A POLYURETHANE-BASED SUPPORT FOR IMMOBILIZING MEMBRANE-BOUND LIPASE

    Directory of Open Access Journals (Sweden)

    M. S. Soares

    Full Text Available Abstract This study conducted an assessment of polyurethane foams that were synthesized by one-shot process and used as a low-cost support to immobilize Mucor circinelloides URM 4182 whole-cells presenting high lipolytic activity. Polyols with different molecular weights (1100 to 6000 g mol-1 were applied to synthesize the polymer matrix, and the agitation speed effect was used for controlling the average pore size of the investigated polyurethane foams. The physical and mechanical properties of the polymers were evaluated by standard test methods, and their morphology was identified by Scanning Electron Microscopy. The immobilization procedure efficiency was assessed by quantifying the capability of the matrices to attach the cells and the catalytic activity of the biocatalysts in both aqueous (olive oil hydrolysis and non-aqueous media (ethanolysis of babassu oil under single and consecutive batch runs. Although all synthesized matrices were suitable to immobilize the whole cells with high catalytic performance, a better set of parameters was attained when the polyol ether with molecular weight of 6000 g mol-1 and 1100 g mol-1 was used. Both matrices yielded immobilized biocatalysts with high hydrolysis and transesterification activities, and exhibited a satisfactory operational stability with 96% and 81% retention of their initial hydrolytic and transesterification activities after three consecutive batch runs.

  5. Segmented polyurethane intravaginal rings for the sustained combined delivery of antiretroviral agents dapivirine and tenofovir.

    Science.gov (United States)

    Johnson, Todd J; Gupta, Kavita M; Fabian, Judit; Albright, Theodore H; Kiser, Patrick F

    2010-02-19

    Dual segment polyurethane intravaginal rings (IVRs) were fabricated to enable sustained release of antiretroviral agents dapivirine and tenofovir to prevent the male to female sexual transmission of the human immunodeficiency virus. Due to the contrasting hydrophilicity of the two drugs, dapivirine and tenofovir were separately formulated into polymers with matching hydrophilicity via solvent casting and hot melt extrusion. The resultant drug loaded rods were then joined together to form dual segment IVRs. Compression testing of the IVRs revealed that they are mechanically comparable to the widely accepted NuvaRing IVR. Physical characterization of the individual IVR segments using wide angle X-ray scattering and differential scanning calorimetry determined that dapivirine and tenofovir are amorphous and crystalline within their polymeric segments, respectively. In vitro release of tenofovir from the dual segment IVR was sustained over 30 days while dapivirine exhibited linear release over the time period. A 90 day accelerated stability study confirmed that dapivirine and tenofovir are stable in the IVR formulation. Altogether, these results suggest that multisegment polyurethane IVRs are an attractive formulation for the sustained vaginal delivery of drugs with contrasting hydrophilicity such as dapivirine and tenofovir. 2009 Elsevier B.V. All rights reserved.

  6. Antimicrobial, Mechanical and Thermal Studies of Silver Particle-Loaded Polyurethane

    Directory of Open Access Journals (Sweden)

    Deepen Paul

    2013-12-01

    Full Text Available Silver-particle-incorporated polyurethane films were evaluated for antimicrobial activity towards two different bacteria: Escherichia coli (E. coli and Staphylococcus aureus (S. aureus. Distributed silver particles sourced from silver nitrate, silver lactate and preformed silver nanoparticles were mixed with polyurethane (PU and variously characterized by field emission scanning electron microscopy (FESEM, fourier transform infra-red (FTIR spectroscopy, X-ray diffraction (XRD and contact angle measurement. Antibacterial activity against E.coli was confirmed for films loaded with 10% (w/w AgNO3, 1% and 10% (w/w Ag lactate and preformed Ag nanoparticles. All were active against S. aureus, but Ag nanoparticles loaded with PU had a minor effect. The apparent antibacterial performance of Ag lactate-loaded PU is better than other Ag ion-loaded films, revealed from the zone of inhibition study. The better performance of silver lactate-loaded PU was the likely result of a porous PU structure. FESEM and FTIR indicated direct interaction of silver with the PU backbone, and XRD patterns confirmed that face-centred cubic-type silver, representative of Ag metal, was present. Young’s modulus, tensile strength and the hardness of silver containing PU films were not adversely affected and possibly marginally increased with silver incorporation. Dynamic mechanical analysis (DMA indicated greater thermal stability.

  7. Preparation, characterization of microencapsulated ammonium polyphosphate and its flame retardancy in polyurethane composites

    International Nuclear Information System (INIS)

    Shen, Ming-Yuan; Chen, Wei-Jen; Kuan, Chen-Feng; Kuan, Hsu-Chiang; Yang, Jia-Ming; Chiang, Chin-Lung

    2016-01-01

    In this study, a novel microencapsulated flame retardant containing ammonium polyphosphate (APP) and an 4,4′-oxydianiline-formaldehyde (OF) resin as the core and shell material was synthesized using in situ polymerization technology. The structure and performance of OF microencapsulated APP (OFAPP) were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The thermal properties of OFAPP were systematically analyzed through thermogravimetric analysis. Flame retardancy tests, such as limiting oxygen index (LOI) and UL-94, were conducted to evaluate the effect of varying the composition of APP and OFAPP in silanol-terminated polyurethane (Si-PU) composites. The results indicated that the microencapsulation of APP with the OF resin resulted in improved hydrophobicity. The results also revealed that the flame retardancy of the Si-PU/OFAPP composite (LOI = 37%) was higher than that of the Si-PU/APP composite (LOI = 23%) at the same additive loading. - Highlights: • A novel microencapsulated flame retardant was synthesized using in situ polymerization technology. • The microencapsulation of ammonium polyphosphate with the polymer resin resulted in improved hydrophobicity. • Polyurethane composites have excellent thermal stability and flame retardance.

  8. A protective effect of dietary calcium against acute waterborne cadmium uptake in rainbow trout

    International Nuclear Information System (INIS)

    Baldisserotto, B.; Kamunde, C.; Matsuo, A.; Wood, C.M.

    2004-01-01

    The present study examined the interactions between elevated dietary calcium (as ionic Ca 2+ in the form of CaCl 2 ·2H 2 O) and acute waterborne Cd exposure (50 μg/l as CdNO 3 for 3 h) on whole body uptake and internal distribution of newly accumulated Cd, Ca 2+ , and Na + in juvenile rainbow trout (Oncorhynchus mykiss). Fish were fed with three diets 20 (control), 30 and 60 mg Ca 2+ /g food: for 7 days before fluxes were measured with radiotracers over a 3 h period. The two elevated Ca 2+ diets reduced the whole body uptake of both Ca 2+ and Cd by >50% and similarly reduced the internalization of both newly accumulated metals in most tissues, effects which reflect the shared branchial uptake route for Ca 2+ and Cd. As the Ca 2+ concentrations of the fluid phases of the stomach and intestinal contents were greatly elevated by the experimental diets, increased gastrointestinal Ca 2+ uptake likely caused the down-regulation of the branchial Ca 2+ (and Cd) uptake pathway. Waterborne Na + uptake and internal distribution were not affected. While plasma Ca 2+ surged after the first two feedings of the 60 mg Ca 2+ /g diet, internal homeostasis was quickly restored. Total Ca 2+ , Na + , and Cl - levels in tissues were not affected by diets. While dietary Ca 2+ protected against waterborne Cd uptake, it did not protect against the relative inhibition of waterborne Ca 2+ uptake caused by waterborne Cd. Acute exposure to 50 μg/l Cd reduced the uptake and internalization of newly accumulated Ca 2+ (but not Na + ) by 70% or more, regardless of diet. Since elevated dietary Ca 2+ reduces waterborne Cd uptake, fish eating a Ca 2+ -rich invertebrate diet may be more protected against waterborne Cd toxicity in a field situation

  9. Reactions of N,N'-bis(2-hydroxyethyl)oxalamide with Ethylene Carbonate and Use of the Obtained Products as Components of Polyurethanes Foams

    International Nuclear Information System (INIS)

    Niemiec, I.Z.

    2010-01-01

    N,N'-bis(2-hydroxyethyl)oxalamide (BHEOA) was subject to hydroxy alkylation with ethylene carbonate (EC). By means of instrumental methods (IR, 1H-NMR, MALDI ToF, GC, and GC-MS), an influence of the reaction conditions on structure and compositions of the obtained products was investigated. The hydroxyalkyl and hydroxy alkoxy derivatives of oxalamide (OA) were obtained by reaction of BHEOA with 210-molar excess of ethylene carbonate (EC, 1,3-dioxolane-2-one). The products have a good thermal stability and possess suitable physical properties as substrates for foamed polyurethanes. The obtained products were used in manufacturing the rigid polyurethane foams which possess enhanced thermal stability and good mechanical properties.

  10. Extraction behavior of uranium(VI) with polyurethane foam

    International Nuclear Information System (INIS)

    Tingchia Huang; Donghwang Chen; Muchang Shieh; Chingtsven Huang

    1992-01-01

    The extraction of uranium(VI) from aqueous solution with polyether-based polyurethane (PU) foam was studied. The effects of the kinds and concentrations of nitrate salts, uranium(VI) concentration, temperature, nitric acid concentration, pH, the content of poly(ethylene oxide) in the polyurethane foam, and the ratio of PU foam weight and solution volume on the extraction of uranium(VI) were investigated. The interferences of fluoride and carbonate ions on the extraction of uranium(VI) were also examined, and methods to overcome both interferences were suggested. It was found that no uranium was extracted in the absence of a nitrate salting-out agent, and the extraction behaviors of uranium(IV) with polyurethane foam could be explained in terms of an etherlike solvent extraction mechanism. In addition, the percentage extraction of a multiple stage was also estimated theoretically

  11. Antimicrobial polyurethane thermosets based on undecylenic acid: synthesis and evaluation.

    Science.gov (United States)

    Lluch, Cristina; Esteve-Zarzoso, Braulio; Bordons, Albert; Lligadas, Gerard; Ronda, Juan C; Galià, Marina; Cádiz, Virginia

    2014-08-01

    In the present study, plant oil-derived surface-modifiable polyurethane thermosets are presented. Polyol synthesis is carried out taking advantage of thiol-yne photopolymerization of undecylenic acid derivatives containing methyl ester or hydroxyl moieties. The prepared methyl ester-containing polyurethanes allow surface modification treatment to enhance their hydrophilicity and impart antimicrobial activity through the following two steps: i) grafting poly(propylene glycol) monoamine (Jeffamine M-600) via aminolysis and ii) Jeffamine M-600 layer complexation with iodine. The antimicrobial activity of the iodine-containing polyurethanes is demonstrated by its capacity to inhibit the growth of Staphylococcus aureus, and Candida albicans in agar media. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Direct transfer of graphene films for polyurethane substrate

    Energy Technology Data Exchange (ETDEWEB)

    Vilani, C.; Romani, E.C.; Larrudé, D.G. [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ (Brazil); Barbosa, Gelza M. [Diretoria de Sistemas de Armas da Marinha, Marinha do Brasil, 20010-00 Rio de Janeiro, RJ (Brazil); Freire, F.L., E-mail: lazaro@vdg.fis.puc-rio.br [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ (Brazil); Centro Brasileiro de Pesquisas Físicas, 22290-180 Rio de Janeiro, RJ (Brazil)

    2015-11-30

    Highlights: • Graphene was prepared by CVD using copper foils as substrates. • Monolayer, bilayer and multilayer graphene were transferred to PU. • Samples were characterized by Raman and optical spectroscopies. • PU/monolayer graphene has transmittance around 80% in visible range. - Abstract: We have proposed the direct transfer of large-area graphene films grown by chemical vapor deposition to polymeric substrate by evaporating of solvents of polyurethane/tetrahydrofurane solution. The graphene films on polyurethane substrates were characterized by Raman spectroscopy, optical and atomic force microscopies and UV–vis spectroscopy measurements. The Raman spectra revealed that it is possible to transfer in a controlled manner monolayer, bilayer and multilayer graphene films over polyurethane substrate.

  13. Direct transfer of graphene films for polyurethane substrate

    International Nuclear Information System (INIS)

    Vilani, C.; Romani, E.C.; Larrudé, D.G.; Barbosa, Gelza M.; Freire, F.L.

    2015-01-01

    Highlights: • Graphene was prepared by CVD using copper foils as substrates. • Monolayer, bilayer and multilayer graphene were transferred to PU. • Samples were characterized by Raman and optical spectroscopies. • PU/monolayer graphene has transmittance around 80% in visible range. - Abstract: We have proposed the direct transfer of large-area graphene films grown by chemical vapor deposition to polymeric substrate by evaporating of solvents of polyurethane/tetrahydrofurane solution. The graphene films on polyurethane substrates were characterized by Raman spectroscopy, optical and atomic force microscopies and UV–vis spectroscopy measurements. The Raman spectra revealed that it is possible to transfer in a controlled manner monolayer, bilayer and multilayer graphene films over polyurethane substrate.

  14. Adaptive hierarchical grid model of water-borne pollutant dispersion

    Science.gov (United States)

    Borthwick, A. G. L.; Marchant, R. D.; Copeland, G. J. M.

    Water pollution by industrial and agricultural waste is an increasingly major public health issue. It is therefore important for water engineers and managers to be able to predict accurately the local behaviour of water-borne pollutants. This paper describes the novel and efficient coupling of dynamically adaptive hierarchical grids with standard solvers of the advection-diffusion equation. Adaptive quadtree grids are able to focus on regions of interest such as pollutant fronts, while retaining economy in the total number of grid elements through selective grid refinement. Advection is treated using Lagrangian particle tracking. Diffusion is solved separately using two grid-based methods; one is by explicit finite differences, the other a diffusion-velocity approach. Results are given in two dimensions for pure diffusion of an initially Gaussian plume, advection-diffusion of the Gaussian plume in the rotating flow field of a forced vortex, and the transport of species in a rectangular channel with side wall boundary layers. Close agreement is achieved with analytical solutions of the advection-diffusion equation and simulations from a Lagrangian random walk model. An application to Sepetiba Bay, Brazil is included to demonstrate the method with complex flows and topography.

  15. Contribution of waterborne radon to home air quality

    International Nuclear Information System (INIS)

    Deb, A.K.

    1994-01-01

    Radon-222 is a member of the uranium decay chain and is formed from the decay of radium-226. Radon and its decay products emit alpha particles during the decay process. If radon is inhaled, alpha particles emitted from inhaled radon and its daughters increase the risk of lung cancer. Radon is soluble in water; thus when radon comes in contact with groundwater it dissolves. The radon concentration in groundwater may range from 100 pCi/L to 1,000,000 pCi/L. When water with a high radon level is used in the home, radon is released from the water to the air and thus can increase indoor air radon concentration. Considering the estimated health risk from radon in public water supply systems, EPA has proposed a maximum contaminant level (MCL) of 300 pCi/L for radon in public drinking water supplies. To address the health risks of radon in water and the proposed regulations, the American Water Works Association Research Foundation (AWWARF) initiated a study to determine the contribution of waterborne radon to radon levels in indoor household air

  16. Fabrication and characterization of cellulose nanocrystal based transparent electroactive polyurethane

    Science.gov (United States)

    Ko, Hyun-U.; Kim, Hyun Chan; Kim, Jung Woong; Zhai, Lindong; Jayaramudu, Tippabattini; Kim, Jaehwan

    2017-08-01

    This paper reports cellulose nanocrystal (CNC) based transparent and electroactive polyurethane (CPPU), suitable for actively tunable optical lens. CNC is used for high dielectric filler to improve electromechanical behavior of CPPU. For high transparency and homogeneous distribution of CNC in polyurethane, CNC-poly[di(ethylene glycol) adipate] is used to play a role of polyol and isocyanate salt. The fabricated CPPU exhibits high transparency (>90%) and 10% of electromechanical strain under 3 V μm-1 electric field. Mechanical, dielectric properties as well as physical and chemical characteristics are investigated to prove the electromechanical behavior of CPPU.

  17. Auxetic Polyurethane Foam (Fabrication, Properties and Applications)

    International Nuclear Information System (INIS)

    Yousif, H.I.Y.

    2012-01-01

    Modern technology requires new materials of special properties. For the last two decades there has been a great interest in a class of materials known as auxetic materials. An auxetic material is a material that has a negative Poisson's ratio which means that this material expands laterally when they subjected to a tensile force unlike most of the other traditional materials. This material has superior properties over the traditional material such as high shear modulus and high impact resistance, which makes this material a good candidate for many engineering applications. In the present research work, auxetic flexible polyurethane polymeric foams having different densities were fabricated from conventional flexible polyurethane polymeric foam at different compression ratios. The microstructure of conventional and processed foams was examined by optical microscope to compare between the two structures. The microstructure of processed foam was compared with the one presented in the literature and it has shown the auxetic structure configuration. This is the first time to produce auxetic foam in Egypt. Conventional and auxetic foam samples having cylindrical and square cross-sections were produced from foams having different densities (25 kg/m 3 and 30 kg/m 3 ). The compression ratios used to produce the auxetic samples are (5.56, 6.94 and 9.26). Four mechanical tests were carried out to get the mechanical properties for both conventional and auxetic foams. Two quasi-static mechanical tests t ension and compression a nd two dynamic mechanical tests H ysteresis and resilience w ere carried out to compare between the conventional and auxetic foams. The quasi-static tensile test was carried out at speed was adjusted to be position control rate of 0.2 mm/s. The compression and hysteresis tests were carried out at strain control rate of 0.3 S -1 . The data recorded from the machine were stress and strain. The modulus of elasticity and Poisson's ratio of the test

  18. Reported waterborne outbreaks of gastrointestinal disease in Australia are predominantly associated with recreational exposure.

    Science.gov (United States)

    Dale, Katie; Kirk, Martyn; Sinclair, Martha; Hall, Robert; Leder, Karin

    2010-10-01

    To examine the frequency and circumstances of reported waterborne outbreaks of gastroenteritis in Australia. Examination of data reported to OzFoodNet between 2001 and 2007. During these seven years, 6,515 gastroenteritis outbreaks were reported to OzFoodNet, most of which were classified as being transmitted person-to-person or from an unknown source. Fifty-four (0.83%) outbreaks were classified as either 'waterborne' or 'suspected waterborne', of which 78% (42/54) were attributed to recreational water and 19% (10/54) to drinking water. Of the drinking water outbreaks, implicated pathogens were found on all but one occasion and included Salmonella sp. (five outbreaks), Campylobacter jejuni (three outbreaks) and Giardia (one outbreak). There have been few waterborne outbreaks detected in Australia, and most of those reported have been associated with recreational exposure. However, there are difficulties in identifying and categorising gastroenteritis outbreaks, as well as in obtaining microbiological and epidemiological evidence, which can result in misclassification or underestimation of water-associated events. Gastroenteritis surveillance data show that, among reported water-associated gastroenteritis outbreaks in Australia, recreational exposure is currently more common than a drinking water source. However, ongoing surveillance for waterborne outbreaks is important, especially as drought conditions may necessitate replacement of conventional drinking water supplies with alternative water sources, which could incur potential for new health risks. © 2010 The Authors. Journal Compilation © 2010 Public Health Association of Australia.

  19. Studies on in vitro biostability and blood compatibility of polyurethane potting compound based on aromatic polymeric MDI for extracorporeal devices.

    Science.gov (United States)

    Hridya, V K; Jayabalan, M

    2009-12-01

    Polyurethane potting compound based on aromatic isocyanurate of polymeric MDI, poly propylene glycol (PPG400) and trimethylol propane (TMP) has significant favourable properties, good pot life and setting characteristics. The cured potting compound of this formulation has appreciable thermal stability and mechanical properties. In vitro biostability of cured potting compound has been found to be excellent without any significant degradation in simulated physiological media and chemical environment. Studies on blood-material interaction and cytotoxicity reveal in vitro blood compatibility and compatibility with cells of this potting compound.

  20. Controlled Release of 5-Aminosalicylic Acid (5-ASA from New Biodegradable Polyurethanes

    Directory of Open Access Journals (Sweden)

    El-Refaie Kenawy

    2010-03-01

    Full Text Available Segmented polyurethanes containing azo aromatic groups in the main chain were synthesized by reaction of 3,3'-azobis(6-hydroxybenzoic acid (ABHB, 5-[4-(hydroxyphenylazo] salicylic acid (HPAS, and 5-[1-hydroxynaphthylazo] salicylic acid (HNAS with hexamethylenediisocyanate (HDI. All synthesized monomers and polymers were characterized by elemental analysis, FTIR, 1H-NMR spectra, TGA and DSC analysis. All the synthesized azo polymers showed good thermal stability and the onset decomposition temperature of all these polymers was found to be above 195 ºC under nitrogen atmosphere.The release of 5-ASA under physiological conditions (pH = 7.8 and pH = 1.5 was investigated at body temperature (37 ºC. The release rate of 5-ASA increased with increasing pH (i.e., 7.8 > 1.5.

  1. Environmentally Friendly Flame-Retardant and Its Application in Rigid Polyurethane Foam

    Directory of Open Access Journals (Sweden)

    Yongjun Chen

    2014-01-01

    Full Text Available A novel Flame-Retardant N-(P,P′-diphenyl phosphorus-based-(3-triethoxysilicon propylamine (DPTP was synthesized in this study. The impact of DPTP on the mechanical properties, thermal stability, and flame retardancy of rigid polyurethane foam (RPUF was studied. The addition of DPTP to RPUF can significantly reduce the undesirable thermal effects and smoke density during combustion, as well as increasing the limiting oxygen index. Compared with pure RPUF, the peak heat release rate of RPUF containing 10 phr of DPTP decreased by 39.4%, while its peak smoke production rate decreased by 49.9%. However, it was also found that the addition of DPTP reduced the compressive strength of RPUF.

  2. Effects of ZnO Nanoparticle on the Gas Separation Performance of Polyurethane Mixed Matrix Membrane.

    Science.gov (United States)

    Soltani, Banafsheh; Asghari, Morteza

    2017-08-11

    Polyurethane (PU)-ZnO mixed matrix membranes (MMM) were fabricated and characterized for gas separation. A thermogravimetric analysis (TGA), a scanning electron microscope (SEM) test and an atomic-force microscopy (AFM) revealed that the physical properties and thermal stability of the membranes were improved through filler loading. Hydrogen Bonding Index, obtained from the Fourier transform infrared spectroscopy (FTIR), demonstrate that the degree of phase separation in PU-ZnO 0.5 wt % MMM was more than the neat PU, while in PU-ZnO 1.0 wt % MMM, the phase mixing had increased. Compared to the neat membrane, the CO₂ permeability of the MMMs increased by 31% for PU-ZnO 0.5 wt % MMM and decreased by 34% for 1.0 wt % ZnO MMM. The CO₂/CH₄ and CO₂/N₂ selectivities of PU-ZnO 0.5 wt % were 18.75 and 64.75, respectively.

  3. [Synthesis and characterization of polylactide-based thermosetting polyurethanes with shape memory properties].

    Science.gov (United States)

    Shi, Shuo; Gu, Lin; Yang, Yihu; Yu, Haibin; Chen, Rui; Xiao, Xianglian; Qiu, Jun

    2016-06-25

    A series of bio-based thermosetting polyurethanes (Bio-PUs) were synthesized by the crosslinking reaction of polylactide and its copolymers diols with hexamethylene diisocyanate (HDI) trimer. The obtained Bio-PUs were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), universal tensile testing machine and cytotoxicity test. Results indicate that the PLA copolymer (P(LA-co-CL)) diols reduced the glass transition temperature (Tg) of Bio-PUs and improved their thermal stability, compared with PLA diols. The Bio-PUs synthesized from P (LA-co-CL) diols exhibit better mechanical performance and shape memory properties. Especially, Young modulus and elongation at break of the obtained Bio-PUs were 277.7 MPa and 230% respectively; the shape recovery time of the obtained Bio-PUs at body temperature was only 93 s. Furthermore, alamar blue assay results showed that the obtained Bio-PUs had no cell toxicity.

  4. Polyurethane and alginate immobilized algal biomass for the removal of aqueous toxic metals

    International Nuclear Information System (INIS)

    Fry, I.V.; Mehlhorn, R.J.

    1992-12-01

    We describe the development of immobilized, processed algal biomass for use as an adsorptive filter in the removal of toxic metals from waste water. To fabricate an adsorptive filter from precessed biomass several crucial criteria must be met, including: (1) high metal binding capacity, (2) long term stability (both mechanical and chemical), (3) selectivity for metals of concern (with regard to ionic competition), (4) acceptable flow capacity (to handle large volumes in short time frames), (5) stripping/regeneration (to recycle the adsorptive filter and concentrate the toxic metals to manageable volumes). This report documents experiments with processed algal biomass (Spirulina platensis and Spirulina maxima) immobilized in either alginate gel or preformed polyurethane foam. The adsorptive characteristics of these filters were assessed with regard to the criteria listed above

  5. Study on the radiation degradation of polyether-polyurethane induced by electron beam

    International Nuclear Information System (INIS)

    Huang Wei; Xiong Jie; Chen Xiaojun; Gao Xiaoling; Xu Yunshu; Fu Yibei

    2007-01-01

    Polyether-urethane samples were irradiated at the dose range from 10 to 2000 kGy by 2 MeV electron beams. Volatile species from the polymer degradation were analyzed quantitatively and qualitatively with GC/MS. Thermal properties and micro-phase separation of the samples were examined by TG and the morphology was studied by TEM and SEM. The results show that the irradiated polyether-polyurethane evolves CO 2 , H 2 , CH 4 and C 2 H 6 , etc. The thermal stabilities between the hard and soft segments in the irradiated samples are different. At high doses, the phase separation in the sample is predominant and the hard segment of sample is more stable. The dose rate affects the soft segment of the irradiated sample much more. (author)

  6. Preconcentration and determination of uranium on to polyurethane foam functionalized with salicylate

    International Nuclear Information System (INIS)

    Sousa, Alvaro S.F. de; Ferreira, Elizabeth de M.M.; Cassella, Ricardo J.

    2009-01-01

    Salicylate was covalently linking with a commercial polyurethane foam (PUF) through -N=N-group generating a stable chelating sorbent (PUFS). The synthesized sorbent was characterized by Infrared Spectrometry (IR) measurement. Good stability towards various solvents was noticed. The pH influence and equilibration shaking time adsorption onto foam functionalized was studied as factors influencing the extraction process of the uranium ion solution. Extraction of uranium was accomplished in 10 minutes. Uranium at ppb level was absorbed as the salicylate complex on powered PUFS at pH about 8.0. Uranium could be achieved in 85 % from a 500 mL uranium solution (0.1 μgmL -1 ) which shows the suitability of salicylate foam for preconcentration analysis. (author)

  7. Synthesis and characterization of bio-based polyurethane from ...

    Indian Academy of Sciences (India)

    Benzoylated tannin prepared by benzoylation of cashewnut husk tannin, was treated with hexame-thylenediisocyanate in the presence of 1,4-butanediol as an extender to prepare thermosetting polyurethane. The sample was characterized using FT–IR and 13C NMR spectra. Thermal, morphological, physico-chemical and ...

  8. WEATHERING DEGRADATION OF A POLYURETHANE COATING. (R828081E01)

    Science.gov (United States)

    The degradation of polyurethane topcoat over a chromate pigmented epoxy primer was examined by atomic force microscopy (AFM), scanning electronic microscopy (SEM), X-ray photo-electron spectroscopy (XPS) and Fourier transform infra-red spectroscopy (FTIR) after the coated pane...

  9. Thermoplastic shape-memory polyurethanes based on natural oils

    International Nuclear Information System (INIS)

    Saralegi, Ainara; Eceiza, Arantxa; Corcuera, Maria Angeles; Johan Foster, E; Weder, Christoph

    2014-01-01

    A new family of segmented thermoplastic polyurethanes with thermally activated shape-memory properties was synthesized and characterized. Polyols derived from castor oil with different molecular weights but similar chemical structures and a corn-sugar-based chain extender (propanediol) were used as starting materials in order to maximize the content of carbon from renewable resources in the new materials. The composition was systematically varied to establish a structure–property map and identify compositions with desirable shape-memory properties. The thermal characterization of the new polyurethanes revealed a microphase separated structure, where both the soft (by convention the high molecular weight diol) and the hard phases were highly crystalline. Cyclic thermo-mechanical tensile tests showed that these polymers are excellent candidates for use as thermally activated shape-memory polymers, in which the crystalline soft segments promote high shape fixity values (close to 100%) and the hard segment crystallites ensure high shape recovery values (80–100%, depending on the hard segment content). The high proportion of components from renewable resources used in the polyurethane formulation leads to the synthesis of bio-based polyurethanes with shape-memory properties. (paper)

  10. Development of a phenomenological constitutive model for polyurethane foams

    International Nuclear Information System (INIS)

    Neilsen, M.K.; Morgan, H.S.; Krieg, R.D.; Yoshimura, H.R.

    1989-01-01

    Rigid, closed-cell, polyurethane foam is used in impact limiters in nuclear waste transport containers. During a hypothetical nuclear waste transport accident, the foam is expected to absorb a significant amount of impact energy by undergoing large inelastic volume reductions. Consequently, the crushing of polyurethane foams must be well characterized and accurately modeled to properly analyze a transport container accident. At the request of Sandia National Laboratories, a series of uniaxial, hydrostatic and triaxial compression tests on polyurethane foams were performed by the New Mexico Engineering Research Institute (NMERI). The combination of hydrostatic and triaxial tests was chosen to provide sufficient data to characterize both the volumetric and deviatoric behaviors of the foams and the coupling between the two responses. Typical results from the NMERI tests are included in this paper. A complete description of these tests can be found in Neilsen et al., 1987. Constitutive models that have been used in the past to model foam did not capture some important foam behaviors observed in the NMERI tests. Therefore, a new constitutive model for rigid, closed-cell, polyurethane foams was developed and implemented in two finite element codes. Development of the new model is discussed in this paper. Also, results from analyses with the new model and other constitutive models are presented to demonstrate differences between the various models. 4 refs., 6 figs., 1 tab

  11. Cell–material interactions on biphasic polyurethane matrix

    Science.gov (United States)

    Dicesare, Patrick; Fox, Wade M.; Hill, Michael J.; Krishnan, G. Rajesh; Yang, Shuying; Sarkar, Debanjan

    2013-01-01

    Cell–matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell–matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

  12. Sorption of Triangular Silver Nanoplates on Polyurethane Foam

    Science.gov (United States)

    Furletov, A. A.; Apyari, V. V.; Garshev, A. V.; Volkov, P. A.; Tolmacheva, V. V.; Dmitrienko, S. G.

    2018-02-01

    The sorption of triangular silver nanoplates on polyurethane foam is investigated as a procedure for creating a nanocomposite sensing material for subsequent use in optical means of chemical analysis. Triangular silver nanoplates are synthesized and characterized, and a simple sorption technique for the formation of a composite material based on these nanoplates is proposed.

  13. Hyaluronan Immobilized Polyurethane as a Blood Contacting Material

    Directory of Open Access Journals (Sweden)

    Feirong Gong

    2010-01-01

    Full Text Available Hyaluronan (hyaluronic acid, HA was immobilized onto the surface of amino-functionalized polyurethane films with the goal of obtaining a novel kind of biomaterial which had the potential in blood-contacting applications. The amino-functionalized polyurethane was prepared by synthesized acidic polyurethane whose pendant carboxyl groups were treated with an excess amount of 1,3-diaminopropane in the presence of N,N-carbonyldiimidazole (CDI. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR, Raman spectroscopy (RS, scanning electron microscopy (SEM, and water contact angle measurement were used to confirm the surface changes at each step of treatment, both in morphologies and chemical compositions. APTT and PT results showed that HA immobilization could prolong the blood coagulation time, thus HA-immobilized polyurethane (PU-HA exhibited improved blood compatibility. Cytotoxicity analysis showed that the PU-HA films synthesized in this study were cytocompatible and could support human vein endothelial cells (HUVECs adhesion and proliferation.

  14. Antimicrobial polyurethane coatings based on ionic liquid quaternary ammonium compounds

    NARCIS (Netherlands)

    Yagci, M.B.; Bolca, S.; Heuts, J.P.A.; Ming, W.; With, de G.

    2011-01-01

    The antimicrobial effect of ionic liquids (ILs) as comonomers in polyurethane surface coatings was investigated. Ionic liquid-containing coatings were prepared from a hydroxyl end-capped liquid oligoester and a triisocyanate crosslinker. Three different commercially available hydroxyl end-capped

  15. Polyurethanes with bio-based and recycled components

    Czech Academy of Sciences Publication Activity Database

    Beneš, Hynek; Vlček, T.; Černá, R.; Hromádková, Jiřina; Walterová, Zuzana; Svitáková, Romana

    2012-01-01

    Roč. 114, č. 1 (2012), s. 71-83 ISSN 1438-7697 R&D Projects: GA MPO 2A-2TP1/135 Institutional research plan: CEZ:AV0Z40500505 Keywords : natural oil * polyol * polyurethane Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.266, year: 2012

  16. Characterization of Novel Castor Oil-Based Polyurethane Polymer Electrolytes

    Directory of Open Access Journals (Sweden)

    Salmiah Ibrahim

    2015-04-01

    Full Text Available Castor oil-based polyurethane as a renewable resource polymer has been synthesized for application as a host in polymer electrolyte for electrochemical devices. The polyurethane was added with LiI and NaI in different wt% to form a film of polymer electrolytes. The films were characterized by using attenuated total reflectance-Fourier transform infrared spectroscopy, dynamic mechanical analysis, electrochemical impedance spectroscopy, linear sweep voltammetry and transference number measurement. The highest conductivity of 1.42 × 10−6 S cm−1 was achieved with the addition of 30 wt% LiI and 4.28 × 10−7 S·cm−1 upon addition of 30 wt% NaI at room temperature. The temperature dependence conductivity plot indicated that both systems obeyed Arrhenius law. The activation energy for the PU-LiI and PU-NaI systems were 0.13 and 0.22 eV. Glass transition temperature of the synthesized polyurethane decreased from −15.8 °C to ~ −26 to −28 °C upon salts addition. These characterizations exhibited the castor oil-based polyurethane polymer electrolytes have potential to be used as alternative membrane for electrochemical devices.

  17. Polyurethanes elastomers with amide chain extenders of uniform length

    NARCIS (Netherlands)

    van der Schuur, J.M.; Noordover, B.A.J.; Noordover, Bart; Gaymans, R.J.

    2006-01-01

    Toluene diisocyanate based polyurethanes with amide extenders were synthesized poly(propylene oxide) with a number average molecular weight of 2000 and endcapped with toluene diisocyanate was used as the polyether segment. The chain extenders were based on poly(hexamethylene terephthalamide):

  18. Novel polycarbonate-based polyurethane elastomers: composition–property relationship

    Czech Academy of Sciences Publication Activity Database

    Špírková, Milena; Pavličevic, J.; Strachota, Adam; Poreba, Rafal; Bera, O.; Kaprálková, Ludmila; Baldrian, Josef; Šlouf, Miroslav; Lazić, N.; Budinski-Simendic, J.

    2011-01-01

    Roč. 47, č. 5 (2011), s. 959-972 ISSN 0014-3057 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethane elastomer * polycarbonate diol * montmorillonite Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.739, year: 2011

  19. Synthesis and characterization of castor oil based polyurethane ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. A series of interpenetrating polymer networks (IPNs) of castor oil based polyurethane/polyacrylo- nitrile (PU/PAN: 80/20, 60/40, 50/50, 40/60 and 20/80) were synthesized by condensation reaction of castor oil with methylene diisocyanate and acrylonitrile, employing benzoyl peroxide (BPO) and ethylene glycol ...

  20. Use of porous polyurethanes for meniscal reconstruction and meniscal prostheses

    NARCIS (Netherlands)

    deGroot, JH; deVrijer, R; Pennings, AJ; Veth, RPH; Jansen, HWB

    In the past, porous materials made of an aromatic polyurethane (PU) were successfully used for meniscal reconstruction in dogs. Since aromatic PUs yield very toxic fragments upon degradation, a linear PU was synthesized by curing a poly(epsilon-caprolactone) and 1,4-trans-cyclohexane diisocyanate I

  1. 78 FR 55641 - Polyurethane-Type Polymers; Tolerance Exemption

    Science.gov (United States)

    2013-09-11

    ...-Type Polymers; Tolerance Exemption AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule... polymers produced by the reaction of either 1,6-hexanediisocyanate; 2,4,4-trimethyl-1,6-hexanediisocyanate... (also known as polyurethane-type polymers), when used as an inert ingredient in a pesticide chemical...

  2. Utilization of natural oils for decomposition of polyurethanes

    Czech Academy of Sciences Publication Activity Database

    Beneš, Hynek; Černá, R.; Ďuračková, Andrea; Látalová, Petra

    2012-01-01

    Roč. 20, č. 1 (2012), s. 175-185 ISSN 1566-2543 R&D Projects: GA MPO 2A-2TP1/135 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethane * oleochemical polyol * chemical recycling Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.495, year: 2012

  3. Synthesis and characterization of castor oil-based polyurethane

    Indian Academy of Sciences (India)

    Polyurethane (PU) based on polyol, derived from castor oil has been synthesized and characterized for potential use as a base material for electrolytes. Transesterification process of castor oil formed a polyol with hydroxyl value of 190 mg KOH g–1 and molecular weight of 2786 g mol–1. The polyols together with 4 ...

  4. Characterization studies of lower and non-TDI polyurethane encapsulants

    International Nuclear Information System (INIS)

    Wilson, M.H.

    1993-09-01

    Polyurethane prepolymers containing toluene diisocyanate (TDI) are used within the Nuclear Weapons complex for many adhesive and encapsulation applications. As part of a program for minimizing hazards to workers and the environment, TDI will be eliminated. This report presents evaluation of alternative encapsulants

  5. Sanitary and hygienic assessment of polyurethane foam compositions

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, V V; Putilina, O.N. (Donetskii NII Gigieny Truda i Professional' nykh Zabolevanii (USSR))

    1990-07-01

    Describes and presents the results of a long-term study performed by the Skochinski Institute and DonUGI into the suitability of various Soviet and foreign polyurethane foams as rock strengtheners in coal mines. Concludes that although further research is needed to clarify the effect of polyurethane absorbed by coal particles and on pneumoconioses, the industrial use of injectable polyisocyanite-based polyurethanes in amounts of up to 1 t/shift and with a minimum air exchange rate of 300 m{sup 3}/min is feasible as long as the safety laws are strictly observed. Those working with this material should be given a medical examination at least once a year. If the substance comes into contact with the skin or eyes, they should be washed with a 1-3% solution of sodium bicarbonate and then pure water; if it contaminates protective clothing this should be degassed in a 5-10% solution of ammonia for 24 hours and then washed. Due to the risk of toxic substances being released from the components of the polyurethane in the event of an endogenic fire, all workers should be equipped with their own personal breathing apparatus.

  6. Recycling Waste Polyurethane as a Carbon Resource in Ironmaking ...

    African Journals Online (AJOL)

    Globally, major avenues available for dealing with waste Poly-Urethane (PU) are disposal at landfill sites and incineration. However, PU contains high levels of carbon and hydrogen that can be recovered for use as reductant in metal extraction processes. In this work the use of post-consumer PU as reductant for the ...

  7. Studies on polyurethane adhesives and surface modification of hydrophobic substrates

    Science.gov (United States)

    Krishnamoorthy, Jayaraman

    This thesis work deals with (a) Curing of reactive, hot-melt polyurethane adhesives and (b) Adsorption studies using different interactions. Research on polyurethanes involves characterization of polyurethane prepolymers and a novel mechanism to cure isocyanate-terminated polyurethane prepolymer by a "trigger" mechanism. Curing of isocyanate-terminated polyurethane prepolymers has been shown to be influenced by morphology and environmental conditions such as temperature and relative humidity. Although the initial composition, final morphology and curing kinetics are known, information regarding the intermediate prepolymer mixture is yet to be established. Polyurethane prepolymers prepared by the reaction of diisocyanates with the primary hydroxyls of polyester diol (PHMA) and secondary hydroxyls of polyether diol (PPG) were characterized. The morphology and crystallization kinetics of a polyurethane prepolymer was compared with a blend of PPG prepolymer (the product obtained by the reaction of PPG with diisocyanate) and a PHMA prepolymer (the product obtained by the reaction of PHMA with diisocyanate) to study the effect of copolymer formed in the polyurethane prepolymer on the above-mentioned properties. Although the morphology of the polyurethane prepolymer is determined in the first few minutes of application, the chemical curing of isocyanate-terminated prepolymer occurs over hours to days. In the literature, different techniques are described to follow the curing kinetics. But there is no established technique to control the curing of polyurethane prepolymer. To make the curing process independent of environmental factors, a novel approach using a trigger mechanism was designed and implemented by using ammonium salts as curing agents. Ammonium salts that are stable at room temperature but decompose on heating to yield active hydrogen-containing compounds, NH3 and H2O, were used as 'Trojan horses' to cure the prepolymer chemically. Research on adsorption

  8. Structural analysis in support of the waterborne transport of radioactive materials

    International Nuclear Information System (INIS)

    Ammerman, D.J.

    1996-01-01

    The safety of the transportation of radioactive materials by road and rail has been well studied and documented. However, the safety of waterborne transportation has received much less attention. Recent highly visible waterborne transportation campaigns have led to DOE and IAEA to focus attention on the safety of this transportation mode. In response, Sandia National Laboratories is conducting a program to establish a method to determine the safety of these shipments. As part of that program the mechanics involved in ship-to-ship collisions are being evaluated to determine the loadings imparted to radioactive material transportation packages during these collisions. This paper will report on the results of these evaluations

  9. Isolation and characterization of a bacterium which utilizes polyester polyurethane as a sole carbon and nitrogen source.

    Science.gov (United States)

    Nakajima-Kambe, T; Onuma, F; Kimpara, N; Nakahara, T

    1995-06-01

    Various soil samples were screened for the presence of microorganisms which have the ability to degrade polyurethane compounds. Two strains with good polyurethane degrading activity were isolated. The more active strain was tentatively identified as Comamonas acidovorans. This strain could utilize polyester-type polyurethanes but not the polyether-type polyurethanes as sole carbon and nitrogen sources. Adipic acid and diethylene glycol were probably the main degradation products when polyurethane was supplied as a sole carbon and nitrogen source. When ammonium nitrate was used as nitrogen source, only diethylene glycol was detected after growth on polyurethane.

  10. Comparison of anti-corrosion properties of polyurethane based composite coatings with low infrared emissivity

    International Nuclear Information System (INIS)

    Wang Yajun; Xu Guoyue; Yu Huijuan; Hu Chen; Yan Xiaoxing; Guo Tengchao; Li Jiufen

    2011-01-01

    Four polyurethane resins, pure polyurethane (PU), epoxy modified polyurethane (EPU), fluorinated polyurethane (FPU) and epoxy modified fluorinated polyurethane (EFPU), with similar polyurethane backbone structure but different grafting group were used as organic adhesive for preparing low infrared emissivity coatings with an extremely low emissivity near 0.10 at 8-14 μm, respectively. By using these four resins, the effect of different resin matrics on the corrosion protection of the low infrared emissivity coatings was investigated in detail by using neutral salt spray test, SEM and FTIR. It was found that the emissivity of the coatings with different resin matrics changes significantly in corrosion media. And the results indicated that the coating using EFPU as organic adhesive exhibited excellent corrosion resistance property which was mainly attributed to the presence of epoxy group and atomic fluorine in binder simultaneously.

  11. Nerve regeneration using tubular scaffolds from biodegradable polyurethane.

    Science.gov (United States)

    Hausner, T; Schmidhammer, R; Zandieh, S; Hopf, R; Schultz, A; Gogolewski, S; Hertz, H; Redl, H

    2007-01-01

    In severe nerve lesion, nerve defects and in brachial plexus reconstruction, autologous nerve grafting is the golden standard. Although, nerve grafting technique is the best available approach a major disadvantages exists: there is a limited source of autologous nerve grafts. This study presents data on the use of tubular scaffolds with uniaxial pore orientation from experimental biodegradable polyurethanes coated with fibrin sealant to regenerate a 8 mm resected segment of rat sciatic nerve. Tubular scaffolds: prepared by extrusion of the polymer solution in DMF into water coagulation bath. The polymer used for the preparation of tubular scaffolds was a biodegradable polyurethane based on hexamethylene diisocyanate, poly(epsilon-caprolactone) and dianhydro-D-sorbitol. EXPERIMENTAL MODEL: Eighteen Sprague Dawley rats underwent mid-thigh sciatic nerve transection and were randomly assigned to two experimental groups with immediate repair: (1) tubular scaffold, (2) 180 degrees rotated sciatic nerve segment (control). Serial functional measurements (toe spread test, placing tests) were performed weekly from 3rd to 12th week after nerve repair. On week 12, electrophysiological assessment was performed. Sciatic nerve and scaffold/nerve grafts were harvested for histomorphometric analysis. Collagenic connective tissue, Schwann cells and axons were evaluated in the proximal nerve stump, the scaffold/nerve graft and the distal nerve stump. The implants have uniaxially-oriented pore structure with a pore size in the range of 2 micorm (the pore wall) and 75 x 700 microm (elongated pores in the implant lumen). The skin of the tubular implants was nonporous. Animals which underwent repair with tubular scaffolds of biodegradable polyurethanes coated with diluted fibrin sealant had no significant functional differences compared with the nerve graft group. Control group resulted in a trend-wise better electrophysiological recovery but did not show statistically significant

  12. Electrospun polyacrylonitrile/polyurethane composite nanofibrous separator with electrochemical performance for high power lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zainab, Ghazala [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Wang, Xianfeng, E-mail: wxf@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Key Laboratory of High Performance Fibers & Products, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Nanofibers Research Center, Modern Textile Institute, Donghua University, Shanghai 200051 (China); Yu, Jianyong [Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Key Laboratory of High Performance Fibers & Products, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Nanofibers Research Center, Modern Textile Institute, Donghua University, Shanghai 200051 (China); Zhai, Yunyun; Ahmed Babar, Aijaz; Xiao, Ke [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Ding, Bin, E-mail: binding@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Key Laboratory of High Performance Fibers & Products, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Nanofibers Research Center, Modern Textile Institute, Donghua University, Shanghai 200051 (China)

    2016-10-01

    Lithium ion batteries (LIBs) for high performance require separators with auspicious reliability and safety. Keeping LIBs reliability and safety in view, microporous polyacrylonitrile (PAN)/polyurethane (PU) nonwoven composite separator have been developed by electrospinning technique. The physical, electrochemical and thermal properties of the PAN/PU separator were characterized. Improved ionic conductivity up to 2.07 S cm{sup −1}, high mechanical strength (10.38 MPa) and good anodic stability up to 5.10 V are key outcomes of resultant membranes. Additionally, high thermal stability displaying only 4% dimensional change after 0.5 h long exposure to 170 °C in an oven, which could be valuable addition towards the safety of LIBs. Comparing to commercialized polypropylene based separators, resulting membranes offered improved internal short-circuit protection function, offering better rate capability and enhanced capacity retention under same observation conditions. These fascinating characteristics endow these renewable composite nonwovens as promising separators for high power LIBs battery. - Highlights: • The PAN/PU based separators were prepared by multi-needle electrospinning technique. • The electrospun separators displays good mechanical properties and thermal stability. • These separators exhibit good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection. • Nanofibrous composite nonwoven possesses stable cyclic performance which give rise to acceptable battery performances.

  13. Optimization of olive oil hydrolysis process using immobilized Lipase from Burkholderia cepacia sp. in Polyurethane

    Directory of Open Access Journals (Sweden)

    Nádia Ligianara Dewes Nyari

    2017-09-01

    Full Text Available The aim of this study was to achieve the best conditions for the  olive oil hydrolysis process at optimal pH and temperature using Burkholderia cepacia lipase immobilized in situ in rigid polyurethane support. The influences of the temperature (13.85 to 56.5ºC and pH (4.18 to 9.82 were evaluated by a central composite rotational experimental design 22. The operational stability and storage conditions were also studied. The olive oil hydrolysis process was optimized in pH 7.0, at 40°C and 15 min of reaction, with 66 and 93 U g-1 of hydrolysis activity in free and immobilized lipase, respectively, with > 700% yield. The immobilized remained stable for up to 40 days of storage at temperatures of 60oC, and for 100 days from 4 to 25°C. The operational stability of the immobilized was 6 continuous cycles. In this way, immobilization showed to be a promising alternative for its application in olive oil hydrolysis, having storage stability and reuse capability.

  14. Burden of Disease Attributed to Waterborne Transmission of Selected Enteric Pathogens, Australia, 2010.

    Science.gov (United States)

    Gibney, Katherine B; O'Toole, Joanne; Sinclair, Martha; Leder, Karin

    2017-06-01

    AbstractUniversal access to safe drinking water is a global priority. To estimate the annual disease burden of campylobacteriosis, nontyphoidal salmonellosis, cryptosporidiosis, giardiasis, and norovirus attributable to waterborne transmission in Australia, we multiplied regional World Health Organization (WHO) estimates of the proportion of cases attributable to waterborne transmission by estimates of all-source disease burden for each study pathogen. Norovirus was attributed as causing the most waterborne disease cases (479,632; 95% uncertainty interval [UI]: 0-1,111,874) followed by giardiasis and campylobacteriosis. The estimated waterborne disability-adjusted life year (DALY) burden for campylobacteriosis (2,004; 95% UI: 0-5,831) was 7-fold greater than other study pathogens and exceeded the WHO guidelines for drinking water quality (1 × 10 -6 DALY per person per year) by 90-fold. However, these estimates include disease transmitted via either drinking or recreational water exposure. More precise country-specific and drinking water-specific attribution estimates would better define the health burden from drinking water and inform changes to treatment requirements.

  15. Bridging adhesion and barrier properties with functional dispersions : towards waterborne anti-corrosion coatings

    NARCIS (Netherlands)

    Soer, W.J.

    2008-01-01

    The successful preparation of waterborne anti-corrosion coatings based on maleic anhydride containing copolymers is described in this thesis. To obtain good anticorrosion coatings, three different properties should be present in a coating system; they should display good mechanical properties, good

  16. A COMPARISON OF THREE ASSAY PROCEDURES FOR DETERMINING CHLORINE INACTIVATION OF WATERBORNE PATHOGENIC BACTERIA

    Science.gov (United States)

    One criterion on which chlorine treatment of water may be based is the concentration (C) in mg/l multiplied by the time (t) in min of exposure or Ct values. We compared different Ct values on waterborne pathogenic bacteria by cultural assay for viability and 2 assays that mea...

  17. Waterborne toxoplasmosis investigated and analyzed under hydrogeological assessment: new data and perspectives for further research

    Science.gov (United States)

    We present a set of data on human and chicken Toxoplasma gondii seroprevalence that was investigated and analyzed in light of groundwater vulnerability information in an area of endemic waterborne toxoplasmosis in Brazil. Hydrogeological assessment was undertaken to conduct water collection from wel...

  18. Global Warming and Trans-Boundary Movement of Waterborne Microbial Pathogens - Book Chapter

    Science.gov (United States)

    Subtle increases in temperature can have profound impacts on the prevalence of various waterborne microbial pathogens. Such impacts may be seen in three major areas, 1) fecally contaminated drinking water, 2) fresh produce that has been irrigated or processed with contaminated wa...

  19. Extraction of uranium from aqueous solution by phosphonic acid-imbedded polyurethane foam

    International Nuclear Information System (INIS)

    Katragadda, S.; Gesser, H.D.; Chow, A.

    1997-01-01

    Phenylphosphonic acid was imbedded into the matrix of the polyurethane foam during the fabrication process of the polymer. The extraction of uranium by phosphonic acid-imbedded polyurethane foam and blank polyurethane (i.e., foam without phosphonic acid functional groups) was investigated. Phosphonic acid-imbedded foam showed superior extractability of uranium from solutions with pH = 7.0 ± 1.5 over a wide range of temperatures. (author)

  20. Bio-Based Polyurethane Containing Isosorbide for Use in Composites and Coatings

    Science.gov (United States)

    2015-04-01

    ARL-TR-7259 ● APR 2015 US Army Research Laboratory Bio-Based Polyurethane Containing Isosorbide for Use in Composites and...copyright notation hereon. ARL-TR-7259 ● APR 2015 US Army Research Laboratory Bio-Based Polyurethane Containing Isosorbide for Use...4. TITLE AND SUBTITLE Bio-Based Polyurethane Containing Isosorbide for Use in Composites and Coatings 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  1. Use of Polyurethane Coating to Prevent Corrosion in Oil and Gas Pipelines Transfer

    OpenAIRE

    Amir Samimi

    2012-01-01

    Corrosion is one of the major problems in the oil and gas industry is one that automatically allocates huge sums annually. Polyurethane is a thermoses polymer with various applications. Using form this polymer has spread for military applications by Otto Bayer in 1930. In one general look polyurethane is product of Iso Syanate and ploy with each other, So that: Iso + ploy = polyurethane. Spend large cost for application and launching oil and gas transitions, has cleared the necessity protecti...

  2. A protective effect of dietary calcium against acute waterborne cadmium uptake in rainbow trout

    Energy Technology Data Exchange (ETDEWEB)

    Baldisserotto, B.; Kamunde, C.; Matsuo, A.; Wood, C.M

    2004-03-30

    The present study examined the interactions between elevated dietary calcium (as ionic Ca{sup 2+} in the form of CaCl{sub 2}{center_dot}2H{sub 2}O) and acute waterborne Cd exposure (50 {mu}g/l as CdNO{sub 3} for 3 h) on whole body uptake and internal distribution of newly accumulated Cd, Ca{sup 2+}, and Na{sup +} in juvenile rainbow trout (Oncorhynchus mykiss). Fish were fed with three diets 20 (control), 30 and 60 mg Ca{sup 2+}/g food: for 7 days before fluxes were measured with radiotracers over a 3 h period. The two elevated Ca{sup 2+} diets reduced the whole body uptake of both Ca{sup 2+} and Cd by >50% and similarly reduced the internalization of both newly accumulated metals in most tissues, effects which reflect the shared branchial uptake route for Ca{sup 2+} and Cd. As the Ca{sup 2+} concentrations of the fluid phases of the stomach and intestinal contents were greatly elevated by the experimental diets, increased gastrointestinal Ca{sup 2+} uptake likely caused the down-regulation of the branchial Ca{sup 2+} (and Cd) uptake pathway. Waterborne Na{sup +} uptake and internal distribution were not affected. While plasma Ca{sup 2+} surged after the first two feedings of the 60 mg Ca{sup 2+}/g diet, internal homeostasis was quickly restored. Total Ca{sup 2+}, Na{sup +}, and Cl{sup -} levels in tissues were not affected by diets. While dietary Ca{sup 2+} protected against waterborne Cd uptake, it did not protect against the relative inhibition of waterborne Ca{sup 2+} uptake caused by waterborne Cd. Acute exposure to 50 {mu}g/l Cd reduced the uptake and internalization of newly accumulated Ca{sup 2+} (but not Na{sup +}) by 70% or more, regardless of diet. Since elevated dietary Ca{sup 2+} reduces waterborne Cd uptake, fish eating a Ca{sup 2+}-rich invertebrate diet may be more protected against waterborne Cd toxicity in a field situation.

  3. Preparation, Physicochemical Properties and Hemocompatibility of Biodegradable Chitooligosaccharide-Based Polyurethane

    Directory of Open Access Journals (Sweden)

    Weiwei Xu

    2018-05-01

    Full Text Available The purpose of this study was to develop a process to achieve biodegradable chitooligosaccharide-based polyurethane (CPU with improved hemocompatibility and mechanical properties. A series of CPUs with varying chitooligosaccharide (COS content were prepared according to the conventional two-step method. First, the prepolymer was synthesized from poly(ε-caprolactone (PCL and uniform-size diurethane diisocyanates (HBH. Then, the prepolymer was chain-extended by COS in N,N-dimethylformamide (DMF to obtain the weak-crosslinked CPU, and the corresponding films were obtained from the DMF solution by the solvent evaporation method. The uniform-size hard segments and slight crosslinking of CPU were beneficial for enhancing the mechanical properties, which were one of the essential requirements for long-term implant biomaterials. The chemical structure was characterized by FT-IR, and the influence of COS content in CPU on the physicochemical properties and hemocompatibility was extensively researched. The thermal stability studies indicated that the CPU films had lower initial decomposition temperature and higher maximum decomposition temperature than pure polyurethane (CPU-1.0 film. The ultimate stress, initial modulus, and surface hydrophilicity increased with the increment of COS content, while the strain at break and water absorption decreased, which was due to the increment of crosslinking density. The results of in vitro degradation signified that the degradation rate increased with the increasing content of COS in CPU, demonstrating that the degradation rate could be controlled by adjusting COS content. The surface hemocompatibility was examined by protein adsorption and platelet adhesion tests. It was found that the CPU films had improved resistance to protein adsorption and possessed good resistance to platelet adhesion. The slow degradation rate and good hemocompatibility of the CPUs showed great potential in blood-contacting devices. In

  4. Effects of surface modification with hydroxyl terminated polydimethylsiloxane on the corrosion protection of polyurethane coating

    International Nuclear Information System (INIS)

    Jeon, Jae Hong; Shon, Min Young

    2014-01-01

    Polyurethane coating was designed to give a hydrophobic property on its surface by modifying it with hydroxyl terminated polydimethylsiloxane and then effects of surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified polyurethane coating were examined using FT-IR/ATR spectroscopy, contact angle measurement and electrochemical impedance test. As results, the surface of polyurethane coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between polyurethane and modifier by the modification. The phase separation tendency is more appreciable when modified by polydimethylsiloxane with higher content. Water transport behavior of the modified polyurethane coating decreased more in that with higher hydrophobic surface property. The decrease in the impedance modulus ⅠZⅠ at low frequency region in immersion test for polyurethane coatings was associated with the water transport behavior and surface hydrophobic properties of modified polyurethane coatings. The corrosion protectiveness of the modified polyurethane coated carbon steel generally increased with an increase in the modifier content, confirming that corrosion protectiveness of the modified polyurethane coating is well agreed with its water transport behavior

  5. Study on thermal properties of synthetic and bio-based polyurethane

    Directory of Open Access Journals (Sweden)

    Šercer Mladen

    2015-01-01

    Full Text Available Polymers that are created by the chemical polymerization of naturally occurring monomers are attracting considerable commercial interest in the last few years because of their non-toxicity, biodegradability and biocompatibility and use of feedstock that is renewable. The development of specialized lignin compounds, such as electrically conducting polymers, engineering plastics and polyurethane, is an area of highest interest and growth. The paper will present the comparison of the mechanical and thermal properties of conventional polyurethane and bio-based polyurethane, i.e. polyurethane based on polyols produced by liquefaction of waste wood biomass.

  6. Biomarkers of waterborne copper exposure in the guppy Poecilia vivipara acclimated to salt water

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Anderson Abel de Souza [Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Biológica, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Hoff, Mariana Leivas Müller [Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Klein, Roberta Daniele [Universidade Federal do Rio Grande, Programa de Pós-Graduação em Ciências Fisiológicas – Fisiologia Animal Comparada, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Cardozo, Janaina Goulart [Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Giacomin, Marina Mussoi [Universidade Federal do Rio Grande, Programa de Pós-Graduação em Ciências Fisiológicas – Fisiologia Animal Comparada, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Pinho, Grasiela Lopes Leães [Universidade Federal do Rio Grande, Instituto de Oceanografia, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); and others

    2013-08-15

    Highlights: •Acute effects of waterborne copper were evaluated in the estuarine guppy Poecilia vivipara. •Fishes were acutely exposed to waterborne copper in salt water. •Waterborne copper affects the response of several biochemical and genetic endpoints. •Catalase, reactive oxygen species, antioxidant capacity and lipid peroxidation are responsive to copper exposure. •Copper exposure induces DNA damages in fish erythrocytes. -- Abstract: The responses of a large suite of biochemical and genetic parameters were evaluated in tissues (liver, gills, muscle and erythrocytes) of the estuarine guppy Poecilia vivipara exposed to waterborne copper in salt water (salinity 24 ppt). Activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione reductase, and glutathione S-transferase), metallothionein-like protein concentration, reactive oxygen species (ROS) content, antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO) were evaluated in liver, gills, and muscle. Comet assay score and nuclear abnormalities and micronucleated cell frequency were analyzed in peripheral erythrocytes. The responses of these parameters were evaluated in fish exposed (96 h) to environmentally relevant copper concentrations (5, 9 and 20 μg L{sup −1}). In control and copper-exposed fish, no mortality was observed over the experimental period. Almost all biochemical and genetic parameters proved to be affected by waterborne copper exposure. However, the response of catalase activity in liver, ROS, ACAP and LPO in muscle, gills and liver, and DNA damages in erythrocytes clearly showed to be dependent on copper concentration in salt water. Therefore, the use of these parameters could be of relevance in the scope of biomonitoring programs in salt water environments contaminated with copper.

  7. Gamma radiation effect on sisal / polyurethane composites without coupling agents

    Directory of Open Access Journals (Sweden)

    Marina Cardoso Vasco

    Full Text Available Abstract Natural fibers and polyurethane based composites may present chemical bonding between the components of the polymer and the lignin of the fiber. The incidence of radiation can cause degradation of the polymeric material and alter its mechanical properties. The objective of this study was to obtain and characterize cold pressed composites from polyurethane derived from castor oil and sisal fibers, without coupling agents, through thermogravimetric and mechanical tests, before and after the incidence of 25 kGy dose of gamma radiation. Woven composites that were not irradiated had maximum values of 4.40 GPa for flexural elastic modulus on three point flexural test and dispersed fiber composite that were not irradiated had maximum values of 2.25 GPa. These materials are adequate for use in non-structural applications in radiotherapy and radiodiagnostic rooms.

  8. Gamma radiation effect on sisal / polyurethane composites without coupling agents

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, Marina Cardoso; Claro Neto, Salvador; Nascimento, Eduardo Mauro; Azevedo, Elaine, E-mail: marina.mcv@gmail.com [University of Patras (Greece); Universidade de Sao Paulo (USP) Sao Carlos, SP (Brazil); Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2017-04-15

    Natural fibers and polyurethane based composites may present chemical bonding between the components of the polymer and the lignin of the fiber. The incidence of radiation can cause degradation of the polymeric material and alter its mechanical properties. The objective of this study was to obtain and characterize cold pressed composites from polyurethane derived from castor oil and sisal fibers, without coupling agents, through thermogravimetric and mechanical tests, before and after the incidence of 25 kGy dose of gamma radiation. Woven composites that were not irradiated had maximum values of 4.40 GPa for flexural elastic modulus on three point flexural test and dispersed fiber composite that were not irradiated had maximum values of 2.25 GPa. These materials are adequate for use in non-structural applications in radiotherapy and radiodiagnostic rooms. (author)

  9. Extraction kinetics of uranium (VI) with polyurethane foam

    International Nuclear Information System (INIS)

    Huang, Ting-Chia; Chen, Dong-Hwang; Huang, Shius-Dong; Huang, Ching-Tsven; Shieh, Mu-Chang.

    1993-01-01

    The extraction kinetics of uranium(VI) from aqueous nitrate solution with polyether-based polyurethane foam was investigated in a batch reactor with automatic squeezing. The extraction curves of uranium(VI) concentration in solution vs. extraction time exhibited a rather rapid exponential decay within the first few minutes, followed by a slower exponential decay during the remaining period. This phenomenon can be attributed to the presence of two-phase structure, hard segment domains and soft segment matrix in the polyurethane foam. A two-stage rate model expressed by a superposition of two exponential curves was proposed, according to which the experimental data were fitted by an optimization method. The extraction rate of uranium (VI) was also found to increase with increasing temperature, nitrate concentration, and hydration of the cation of nitrate salt. (author)

  10. The small angle neutron scattering study on the segmented polyurethane

    International Nuclear Information System (INIS)

    Sudirman; Gunawan; Prasetyo, S.M.; Karo Karo, A.; Lahagu, I.M.; Darwinto, Tri

    1999-01-01

    The distance between hard segment (HS) and soft segment (SS) of segmented polyurethane have been determined using the Small Angle Neutron Scattering (SANS) technique. The segmented Polyurethanes (SPU) are linear multiblock copolymers, which include elastomer thermoplastic. SPU consist of hard segment and soft segment, each has tendency to make a group with similar type to form a domain. The soft segments used were polypropylene glycol (PPG) and 4,4 diphenylmethane diisocyanate (MDI), while l,4 butanediol (BD) was used as hard segment. The characteristic of SPU depends on its phase structure which is affected by several factors, such as type of chemical formula and the composition of the HS and SS, solvent as well as the synthesizing process. The samples used in this study were SPU56 and SPU68. Based on the appearance of SANS profile, it was obtained that domain distances are 12.32 nm for the SPU56 and 19 nm for the SPU68. (author)

  11. Glycolysis of flexible polyurethane foam in recycling of car seats

    Czech Academy of Sciences Publication Activity Database

    Beneš, Hynek; Rösner, J.; Holler, Petr; Synková, Hana; Kotek, Jiří; Horák, Zdeněk

    2007-01-01

    Roč. 18, č. 2 (2007), s. 149-156 ISSN 1042-7147. [International Conference on Polymeric Materials in Automotive , Slovak Rubber Conference /17./. Bratislava, 10.5.2005-12.5.2005] R&D Projects: GA MŽP SL/7/26/05 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethanes * foams * recycling Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.504, year: 2007

  12. Improved Lignin Polyurethane Properties with Lewis Acid Treatment

    OpenAIRE

    Chung, Hoyong; Washburn, Newell R.

    2012-01-01

    Chemical modification strategies to improve the mechanical properties of lignin-based polyurethanes are presented. We hypothesized that treatment of lignin with Lewis acids would increase the concentration of hydroxyl groups available to react with diisocyanate monomers. Under the conditions used, hydrogen bromide-catalyzed modification resulted in a 28% increase in hydroxyl group content. Associated increases in hydrophilicity of solvent-cast thin films were also recorded as evidenced by ...

  13. Preparation and characterization of polyurethane - Fe powder composites

    Czech Academy of Sciences Publication Activity Database

    Špírková, Milena; Bureš, R.; Fáberová, M.; Trchová, Miroslava; Strachota, Adam; Kaprálková, Ludmila

    2011-01-01

    Roč. 11, 3/4 (2011), s. 290-299 ISSN 1335-8987 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethanes * polybutadiene diol * Fe powder Subject RIV: CD - Macromolecular Chemistry http://www.imr.saske.sk/pmp/issue/3-4-2011/PMP_Vol11_No3-4_p_290-299.pdf

  14. The effects of using immobilizer made of the polyurethane foam

    International Nuclear Information System (INIS)

    Kim, Yong Hwan; Chung, Sang Hwa; Kim, Hwa Young; Lim, Shin Taek; Oh, Sae Dong

    1992-01-01

    The immogilzer for control the patient movement during the radiation beam on was made of the polyurethane foam. The time consumption is abut 8 minutes for completely making the immobilizer. In this experimental study, the effects of using the individual immobilizer have shown that the patients have had always a same position with comfortable and high reproducibilities. Furthermore, it has shown the time for patient setup was decreased by using the individual patient immobilizer.

  15. Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

    OpenAIRE

    Jiříček, T.; Komárek, M.; Lederer, T.

    2017-01-01

    Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest ...

  16. Polyester Polyols from Waste PET Bottles for Polyurethane Rigid Foams

    OpenAIRE

    Evtimova, Rozeta; Lozeva, Yordanka; Schmidt, Karl-Heinz; Wotzka, Michael; Wagner, Peter; Behrendt, Gerhard

    2003-01-01

    This paper describes a modified process to produce polyester polyols from PET wastes derived from the “bottle fraction residue” of the German Dual System (DSD) [11] employing a waste oligoester condensate of the polyesterification process with the addition of some glycols of longer chain and occasional modification with further dicarboxylic acids to produce polyester polyols of a broad range of properties which are further reacted to form polyurethane or polyisocyanurate rigid foams for insul...

  17. Modyfication of the Rigid Polyurethane-Polyisocyanurate Foams

    OpenAIRE

    Bogusław Czupryński; Joanna Liszkowska; Joanna Paciorek-Sadowska

    2014-01-01

    The effect of polyethylene glycol 1500 on physicomechanical properties of rigid polyurethane-polyisocyanurate (PUR-PIR) foams has been studied. It was found that application of polyethylene glycol 1500 for synthesis of foams in amount from 0% to 20% w/w had an effect on reduction of brittleness and softening point, while the greater the increase in compressive strength the higher its content in foam composition was. Wastes from production of these foams were ground and subjected to glycolysis...

  18. The important parameters of polyurethane's properties and preparation

    International Nuclear Information System (INIS)

    Rad, A.S.

    2009-01-01

    Polyurethane (PU) is a type of plastic rind is formed by reacting a polyol (a polymeric alcohol with more than. two reactive hydroxyl groups per molecule) with diisocyanates or polymeric isocyanate in the presence of suitable catalysts and additives. Variations in the number of substitutions and the spacing between and within branch chains produce PUs ranging from linear to branched and flexible to rigid. Linear PUs are used for the manufacture of fibers and molding. The structure of polyurethane can be medley containing 'hard' and 'soft' sect, which contribute to the harmony between rigid and elastomeric properties. The chemical composition and molecular weight distribution (MWD)- of the incorporated soft block influence the macroscopic properties of the resulting coating. In modifying the backbone structure of PU coatings it is necessary to consider the end use for the coating and the cost of modification: The properties of the modified PU coating, The resistance of the coating towards mechanical and The compatibility of the coating and the substrate over the temperature range of expected application and The between the benefits to be gained and the additional cost are the parameters that must be A surface functionalization of a synthetic polyurethane was carried out by using biofunctional moieties to obtain a material with the appropriate mechanical properties and processing conditions. (author)

  19. PLATELET ADHESION TO POLYURETHANE UREA UNDER PULSATILE FLOW CONDITIONS

    Science.gov (United States)

    Navitsky, Michael A.; Taylor, Joshua O.; Smith, Alexander B.; Slattery, Margaret J.; Deutsch, Steven; Siedlecki, Christopher A.; Manning, Keefe B.

    2014-01-01

    Platelet adhesion to a polyurethane urea surface is a precursor to thrombus formation within blood-contacting cardiovascular devices, and platelets have been found to adhere strongly to polyurethane surfaces below a shear rate of approximately 500 s−1. The aim of the current work is to determine platelet adhesion properties to the polyurethane urea surface as a function of time varying shear exposure. A rotating disk system is used to study the influence of steady and pulsatile flow conditions (e.g. cardiac inflow and sawtooth waveforms) for platelet adhesion to the biomaterial surface. All experiments retain the same root mean square angular rotation velocity (29.63 rad/s) and waveform period. The disk is rotated in platelet rich bovine plasma for two hours with adhesion quantified by confocal microscopy measurements of immunofluorescently labeled bovine platelets. Platelet adhesion under pulsating flow is found to exponentially decay with increasing shear rate. Adhesion levels are found to depend upon peak platelet flux and shear rate regardless of rotational waveform. In combination with flow measurements, these results may be useful for predicting regions susceptible to thrombus formation within ventricular assist devices. PMID:24721222

  20. Study on polyurethane foamed concrete for use in structural applications

    Directory of Open Access Journals (Sweden)

    Iman Kattoof Harith

    2018-06-01

    Full Text Available Recently, foamed concrete is being widely used in civil construction and building, because of its high fluidity and settlement, low self-weight and low thermal conductivity. However, it has some major setbacks such as low strength and increased shrinkage at later ages. The strength gain of concrete depends upon several variables; one of these is the curing conditions. This work aims to study the potential production of foamed concrete as a sustainable structural material by varying the curing methods. For this purpose, sample cubes, cylinders and prisms were prepared to find the compressive strength, modulus of elasticity and drying shrinkage at different ages. Samples of the polyurethane foamed concrete cured under four different curing regimes (water, moisture, sealing by membrane-forming curing compound and air curing. At the end of the study, polyurethane foamed concrete used for this study has shown the potential for use in structural applications. Also, the results show that the samples cured by moisture have the highest compressive strength at all ages. Keywords: Polyurethane foamed concrete, Curing conditions, Fly ash, Compressive strength, Static modulus of elasticity drying shrinkage

  1. Chemical and Enzymatic Hydrolysis of Polyurethane/Polylactide Blends

    Directory of Open Access Journals (Sweden)

    Joanna Brzeska

    2015-01-01

    Full Text Available Polyether-esterurethanes containing synthetic poly[(R,S-3-hydroxybutyrate] (R,S-PHB and polyoxytetramethylenediol in soft segments and polyesterurethanes with poly(ε-caprolactone and poly[(R,S-3-hydroxybutyrate] were blended with poly([D,L]-lactide (PLA. The products were tested in terms of their oil and water absorption. Oil sorption tests of polyether-esterurethane revealed their higher response in comparison to polyesterurethanes. Blending of polyether-esterurethanes with PLA caused the increase of oil sorption. The highest water sorption was observed for blends of polyether-esterurethane, obtained with 10% of R,S-PHB in soft segments. The samples mass of polyurethanes and their blends were almost not changed after incubation in phosphate buffer and trypsin and lipase solutions. Nevertheless the molecular weight of polymers was significantly reduced after degradation. It was especially visible in case of incubation of samples in phosphate buffer what suggested the chemical hydrolysis of polymer chains. The changes of surface of polyurethanes and their blends, after incubation in both enzymatic solutions, indicated on enzymatic degradation, which had been started despite the lack of mass lost. Polyurethanes and their blends, contained more R,S-PHB in soft segments, were degraded faster.

  2. A multilayered polyurethane foam technique for skin graft immobilization.

    Science.gov (United States)

    Nakamura, Motoki; Ito, Erika; Kato, Hiroshi; Watanabe, Shoichi; Morita, Akimichi

    2012-02-01

    Several techniques are applicable for skin graft immobilization. Although the sponge dressing is a popular technique, pressure failure near the center of the graft is a weakness of the technique that can result in engraftment failure. To evaluate the efficacy of a new skin graft immobilization technique using multilayered polyurethane foam in vivo and in vitro. Twenty-six patients underwent a full-thickness skin graft. Multiple layers of a hydrocellular polyurethane foam dressing were used for skin graft immobilization. In addition, we created an in vitro skin graft model that allowed us to estimate immobilization pressure at the center and edges of skin grafts of various sizes. Overall mean graft survival was 88.9%. In the head and neck region (19 patients), mean graft survival was 93.6%. Based on the in vitro outcomes, this technique supplies effective pressure (skin graft. This multilayered polyurethane foam dressing is simple, safe, and effective for skin graft immobilization. © 2011 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

  3. Green waste cooking oil-based rigid polyurethane foam

    Science.gov (United States)

    Enderus, N. F.; Tahir, S. M.

    2017-11-01

    Polyurethane is a versatile polymer traditionally prepared using petroleum-based raw material. Petroleum, however, is a non-renewable material and polyurethane produced was found to be non-biodegradable. In quest for a more environmentally friendly alternative, wastecooking oil, a highly abundant domestic waste with easily derivatized structure, is a viable candidate to replace petroleum. In this study,an investigation to determine physical and chemical properties of rigid polyurethane (PU) foam from waste cooking oil (WCO) was carried out. WCO was first adsorbed by using coconut husk activated carbon adsorbent prior to be used for polyol synthesis. The purified WCO was then used to synthesize polyol via transesterification reaction to yield alcohol groups in the WCO chains structure. Finally, the WCO-based polyol was used to prepare rigid PU foam. The optimum formulation for PU formation was found to be 90 polyol: 60 glycerol: 54 water: 40 diethanolamine: 23 diisocyanate. The rigid PU foam has density of 208.4 kg/m3 with maximum compressive strength and capability to receive load at 0.03 MPa and 0.09 kN, respectively. WCO-based PU can potentially be used to replace petroleum-based PU as house construction materials such as insulation panels.

  4. (Biodegradable Ionomeric Polyurethanes Based on Xanthan: Synthesis, Properties, and Structure

    Directory of Open Access Journals (Sweden)

    T. V. Travinskaya

    2017-01-01

    Full Text Available New (biodegradable environmentally friendly film-forming ionomeric polyurethanes (IPU based on renewable biotechnological polysaccharide xanthan (Xa have been obtained. The influence of the component composition on the colloidal-chemical and physic-mechanical properties of IPU/Xa and based films, as well as the change of their properties under the influence of environmental factors, have been studied. The results of IR-, PMS-, DMA-, and X-ray scattering study indicate that incorporation of Xa into the polyurethane chain initiates the formation of a new polymer structure different from the structure of the pure IPU (matrix: an amorphous polymer-polymer microdomain has occurred as a result of the chemical interaction of Xa and IPU. It predetermines the degradation of the IPU/Xa films as a whole, unlike the mixed polymer systems, and plays a key role in the improvement of material performance. The results of acid, alkaline hydrolysis, and incubation into the soil indicate the increase of the intensity of degradation processes occurring in the IPU/Xa in comparison with the pure IPU. It has been shown that the introduction of Xa not only imparts the biodegradability property to polyurethane, but also improves the mechanical properties.

  5. A waterborne outbreak of multiple diarrhoeagenic Escherichia coli infections associated with drinking water at a school camp

    Directory of Open Access Journals (Sweden)

    Jungsun Park

    2018-01-01

    Conclusions: This outbreak points to the importance of drinking water quality management in group facilities where underground water is used and emphasizes the need for periodic sanitation and inspection to prevent possible waterborne outbreaks.

  6. Mechanical Properties of Dynamically Vulcanized Thermoplastic Polyurethane (TPU/Polybutadiene Rubber (BR Blends

    Directory of Open Access Journals (Sweden)

    Ji-Hoo Kim

    2017-01-01

    Full Text Available To obtain thermoplastic polyurethane (TPU with low hardness, dynamically vulcanized TPU/polybutadiene rubber(BR(70/30 blends were prepared. The effect of dicumyl peroxide (DCP content and stabilizers on the tensile strength and elongation at break of the dynamically vulcanized blends was examined. The tensile strength and elongation at break of the dynamically vulcanized blends decrease with increasing content of DCP. The addition of optimal content of stabilizer leads to the improvement of tensile strength and elongation at break of the blends. Also, the effect of sulfur cure systems and accelerators on the tensile strength and elongation of the blends was investigated. The tensile strength and elongation at break of all the dynamically vulcanized TPU/BR (70/30 blends using 1-step processing are not higher than those of simple TPU/BR (70/30 blends. However, the tensile strength and elongation of the dynamically vulcanized blends prepared at 8 min (mixing time using 2-step processing are higher than those of the simple blends.

  7. Thermal Properties of Polyurethane-Polyisocyanurate Foams Based on Poly(ethylene terephthalate Waste

    Directory of Open Access Journals (Sweden)

    Irena VITKAUSKIENĖ

    2011-09-01

    Full Text Available A series of polyurethane-polyisocyanurate (PU-PIR foams synthesized from PET-waste-derived aromatic polyester polyols (APP was studied using thermogravimetric analysis, Cone calorimeter and burning tests. The effect of chemical structure of the APP containing fragments of glycerol, adipic acid, poly(propylene glycol or hexanediol on thermal stability and flame resistance of the PU-PIR foams was elucidated. PU-PIR foams prepared from APP containing fragments of glycerol and/or adipic acid had higher thermal stability and lower weight loss at 330 °C. The foams based on APP derived from industrial PET waste were characterized by relatively low heat release and low smoke production. The presence of the fragments of the functional additives glycerol and/or adipic acid in the structure of APP used for production of PU-PIR foams, marginally decreased the heat release and slightly increased the smoke production.http://dx.doi.org/10.5755/j01.ms.17.3.588

  8. Double-chain phospholipid end-capped polyurethanes: Synthesis, characterization and platelet adhesion study

    International Nuclear Information System (INIS)

    Tan Dongsheng; Zhang Xiaoqing; Li Jiehua; Tan Hong; Fu Qiang

    2012-01-01

    A novel phospholipid containing double chains and phosphotidylcholine polar head groups, 2-(10-(2-aminoethylamino)-10-oxodecanamido)-3-(decyloxy)-3-oxopropyl phosphorylcholine (ADDPC), was synthesized and characterized. Two kinds of double-chain phospholipid end-capped polyurethanes with different soft segments were prepared. The structure of prepared polyurethanes was characterized by X-ray photoelectron spectroscopic (XPS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrometry and atomic force microscope (AFM), which indicated that the double-chain phospholipids enriched onto the top surface of the prepared polyurethane films. The preliminary evaluation of blood compatibility showed that these novel phospholipid end-capped polyurethanes could suppress platelet adhesion and activation effectively. This property did not depend on the chemical structure of polyurethanes. In addition, according to tensile test results, the phospholipid polyurethanes kept good mechanical properties in comparison with original polyurethanes. It is suggested that double-chain phospholipid end-caption has good potential for achieving both hemocompatibility and good mechanical properties simultaneously for polyurethanes.

  9. The study of the curing of the polyurethane coating by method of IR spectroscopy

    Directory of Open Access Journals (Sweden)

    N. A. Korshunova

    2016-12-01

    Full Text Available The results of the study of the curing process of polyurethane compositions with participation of two different catalysts by the method of IR spectroscopy are given. The time dependences of curing of polyurethane coatings from concentrations of catalysts were determined, on the basis of which the most effective catalyst was selected.

  10. MORPHOLOGICAL CHANGES IN POLYURETHANE COATINGS ON EXPOSURE TO WATER. (R828081E01)

    Science.gov (United States)

    When a polyurethane self-priming coating on a sol-gel treated aluminum panel was immersed in dilute Harrison's solution, subsequent change of the polyurethane coating surface was inspected with atomic force microscopy (AFM) and scanning electron microscopy (SEM). After immersi...

  11. Electrospun Polyurethane Fibers for Absorption of Volatile Organic Compounds from Air

    NARCIS (Netherlands)

    Scholten, E.; Bromberg, L.; Rutledge, G.C.; Hatton, T.A.

    2011-01-01

    Electrospun polyurethane fibers for removal of volatile organic compounds (VOC) from air with rapid VOC absorption and desorption have been developed. Polyurethanes based on 4,4-methylenebis(phenylisocyanate) (MDI) and aliphatic isophorone diisocyanate as the hard segments and butanediol and

  12. Light Scattering of TiO2 Nanoparticles Embedded in Polyurethane

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Canulescu, Stela; Johansen, Villads Egede

    A new approach of enhancing light scattering in polyurethane polymer through the effect of TiO2 nanoparticles (NP) is explored. The TiO2 NP with sizes of 360 nm, 410 nm and 500 nm were dispersed in polyurethane polymer in concentrations ranging from 0.25 wt% up to 2 wt%. Reflectivity and UV-visible...

  13. Biobased composites from cross-linked soybean oil and thermoplastic polyurethane

    Science.gov (United States)

    Soybean oil is an important sustainable material. Crosslinked acrylated epoxidized soybean oil (AESO) is brittle and the incorporation of thermoplastic polyurethane improves its toughness. The hydrophilic functional groups from both oil and polyurethane contribute to the adhesion of the blend compon...

  14. The use of polyurethane foam as an antimicrobial dressing material in hand surgery

    Directory of Open Access Journals (Sweden)

    Nebil Yesiloglu

    2015-12-01

    Full Text Available Polyurethane foam is generally used in negative pressure-assisted wound closure therapy. It provides an antimicrobial environment around the wound, while reducing the rate of skin maceration. The authors used polyurethane foam in routine hand dressings after hand surgery operations that were performed for both congenital and acquired purposes. [Hand Microsurg 2015; 4(3.000: 91-92

  15. Polyurethanes irradiation by accelerated electrons: molecular and supramolecular evolution, incidence on the extractable and biomedical implications

    International Nuclear Information System (INIS)

    Guignot, C.

    2002-11-01

    Face to the development of radiosterilization and polymers medical devices it was wished to study the behavior of polyurethanes under accelerated electrons in oxidizing atmosphere. This study has been made to reveal the physico chemical and organisational modifications of polyurethanes for a medical use. (N.C.)

  16. Self-cleaning behavior in polyurethane/silica coatings via formation of a hierarchical packed morphology of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hejazi, Iman [Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, P.O. Box 15875/4413, Tehran (Iran, Islamic Republic of); Mir Mohamad Sadeghi, Gity, E-mail: Gsadeghi@aut.ac.ir [Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, P.O. Box 15875/4413, Tehran (Iran, Islamic Republic of); Seyfi, Javad [Department of Chemical Engineering, Shahrood Branch, Islamic Azad University, P.O. Box 36155-163, Shahrood (Iran, Islamic Republic of); Jafari, Seyed-Hassan [School of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Khonakdar, Hossein Ali [Iran Polymer and Petrochemical Institute, P.O. Box 14965/115, Tehran (Iran, Islamic Republic of)

    2016-04-15

    Graphical abstract: - Highlights: • Self-cleaning behavior was imparted to the hydrophilic polyurethane. • A hierarchical packed morphology is responsible for the superhydrophobicity. • Prolonged pressing process cannot lead to superhydrophobicity due to migration of TPU. • Samples exhibited excellent stability against media with a wide range of pH values. - Abstract: In the current research, a hierarchical morphology comprising of packed assembly of nanoparticles was induced in thermoplastic polyurethane (TPU)/silica nanocomposite coatings in order to achieve self-cleaning behavior. Moderately hydrophilic behavior of TPU hinders its transforming to a superhydrophobic material. In the presented method, a very thin layer of silica nanoparticles is applied to the surface of TPU sheets under elevated temperature and pressure. As temperature and pressure of the process remain unchanged, processing time was considered as a main variable. Based on scanning electron microscopy and confocal microscopy results, it was found that at a certain processing time, nanoparticles can form an utterly packed morphology leading to a self-cleaning behavior. Once the process was prolonged, TPU macromolecules found the chance to migrate onto the coating's top layer due to the enhanced mobility of chains at high temperature. This observation was further proved by X-ray photoelectron spectroscopy analysis and cross-sectional morphology. The presented method has promising potentials in transforming intrinsically hydrophilic polymers into superhydrophobic materials with self-cleaning behavior.

  17. Lipid for biodiesel production from attached growth Chlorella vulgaris biomass cultivating in fluidized bed bioreactor packed with polyurethane foam material.

    Science.gov (United States)

    Mohd-Sahib, Ainur-Assyakirin; Lim, Jun-Wei; Lam, Man-Kee; Uemura, Yoshimitsu; Isa, Mohamed Hasnain; Ho, Chii-Dong; Kutty, Shamsul Rahman Mohamed; Wong, Chung-Yiin; Rosli, Siti-Suhailah

    2017-09-01

    The potential to grow attached microalgae Chlorella vulgaris in fluidized bed bioreactor was materialized in this study, targeting to ease the harvesting process prior to biodiesel production. The proposed thermodynamic mechanism and physical property assessment of various support materials verified polyurethane to be suitable material favouring the spontaneous adhesion by microalgae cells. The 1-L bioreactor packed with only 2.4% (v/v) of 1.00-mL polyurethane foam cubes could achieve the highest attached growth microalgae biomass and lipid weights of 812±122 and 376±37mg, respectively, in comparison with other cube sizes. The maturity of attached growth microalgae biomass for harvesting could also be determined from the growth trend of suspended microalgae biomass. Analysis of FAME composition revealed that the harvested microalgae biomass was dominated by C16-C18 (>60%) and mixture of saturated and mono-unsaturated fatty acids (>65%), satiating the biodiesel standard with adequate cold flow property and oxidative stability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. SPECIFIC FEATURES OF OLIGOMERIC PRODUCT SOLIDIFICATION FROM POLYURETHANE WASTES AND THEIR PRACTICAL APPLICATION

    Directory of Open Access Journals (Sweden)

    V. Belyatsky

    2012-01-01

    Full Text Available The paper considers a possibility to use secondary polyurethane obtained by  thermal depolymerization of wastes on the basis of cross-linked polyurethane (polyurethane adduct and isocyanate. An effect of density dependence of the obtained polyurethane samples on nature and quantity of solvent has been revealed and it is significantly observed while using low-boiling solvents. The influence of adduct/solidification agent ratio on mechanical hardness of the obtained samples has been studied in the paper. The paper shows that the most optimal ratio is within the following limits – from 7/1 to 10/1. Plasticizing effect of polyurethane adduct on bitumen materials has been also found in the paper.A conclusion has been made that there is a possibility of practical usage of composites in building and road-building materials. 

  19. Synthesis and optical properties of polyurethane foam modified with silver nanoparticles

    International Nuclear Information System (INIS)

    Apyari, V V; Volkov, P A; Dmitrienko, S G

    2012-01-01

    This paper for the first time describes peculiarities of synthesis of polyurethane foam modified with silver nanoparticles as a potential material for optical sensors in analytical chemistry. We found that the unique sorptional properties of polyurethane foam gave an opportunity to perform such a synthesis by two different approaches. The first one was based on sorption of previously synthesized in-solution nanoparticles by polyurethane foam, the second one consisted in preparation of nanoparticles directly in polyurethane foam matrix. This possibility is novel and interesting for practical use because the nanoparticles in polyurethane foam are capable of surface plasmon resonance. The influence of different factors during the synthesis was investigated and the optimal conditions were found. The samples prepared were characterized by diffuse reflectance spectroscopy and scanning electron microscopy. On the basis of the results obtained we first suggested that this material is attractive from the viewpoint of analytical chemistry as a convenient analytical form for determination of oxidants and reductants

  20. Reflectance spectroscopy from TiO2 particles embedded in polyurethane

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Canulescu, Stela; Johansen, Villads Egede

    2013-01-01

    This paper presents the results of a physical simulation carried out using TiO2-Polyurethane composite coating on bright aluminium surface to understand the light scattering effect for designing white surfaces. Polyurethane matrix is selected due to the matching refractive index (1.7) with Al2O3...... layer on anodized aluminium surfaces. Three different TiO2 particle distributions were dispersed in polyurethane and spin coated onto high gloss and caustic etched aluminium substrates. Reflectance spectra of TiO2-polyurethane films of various concentrations were analysed using an integrating sphere....... The results show that the TiO2-polyurethane coatings have a high diffuse reflectance as a result of multiple scattering from TiO2 particles. Diffuse reflectance spectra of TiO2 containing films vary weakly with particle concentration and reach a steady state value at a concentration of 0.75 wt.%. Using...

  1. Cylindrical multiwire two-coordinate chamber with foam-polyurethane supporting element

    International Nuclear Information System (INIS)

    Vakhtin, V.G.; Travkin, V.I.

    1988-01-01

    Construction and technology of producing the two-coordinate cylindrical chamber with foam-polyurethane supporting element are described. Use of foam-polyurethane permits to reduce the substance quantity at particle path up to 0.2 g/cm 2 . The supporting element represents a foam-polyurethane tube the outside diameter being 126 mm, the thickness - 6.5 mm and the length 600 mm. Special attention was paid to study of elastic properties of foam-polyurethane tubes and to the effect of the chamber working fluid vapors on the tube sizes. It is stated that after a sustained load (3750 N for 6 days) the tube shrinks by 1.25 %. The foam-polyurethane supporting element arranged in 50% argon + 33% methane + 17% methylane mixture didn't change its sizes in the limit of 0.05% for three weeks. The chamber operates under self-qquenching streamer conditions

  2. Studies on incorporation of exfoliated bentonitic clays in polyurethane foams for increasing flame retardancy

    International Nuclear Information System (INIS)

    Quagliano, J; García, Irma Gavilán

    2012-01-01

    In this contribution we report the results of studying the incorporation of exfoliated bentonitic clays into polyurethane foams. A suspension in water of a sodium bentonite from Argentine Patagonia was interchanged with cetyl trimethyl ammonium bromide (CTAB) for 4 h at 80°C, rendering an exfoliated clay, which is nanometric in only one dimension. This nanoclay, when dispersed in the polyurethane, resulted in the same fire retardancy rating (UL-94) than when polyurethane was treated with a commercial nanoclay. Scanning electron microscopy (SEM) at low augmentations of polyurethane samples treated with the synthethized nanoclay (2,5% w/w) showed no differences respect to untreated polyurethane, except for the irregularity of void edges.

  3. Experimental study of polyurethane foam reinforced soil used as a rock-like material

    Directory of Open Access Journals (Sweden)

    Eren Komurlu

    2015-10-01

    Full Text Available In this study, polyurethane foam type thermoset polymerizing, due to chemical reaction between its liquid ingredients, was tested as binder after solidifying and then a rock-like material mixing with a sandy silt type soil was prepared. The uniaxial compressive strengths (UCSs of polyurethane foam reinforced soil specimens were determined for different polyurethane ratios in the mixture. Additionally, a series of tests on slake durability, impact value, freezing–thawing resistance, and abrasion resistance of polyurethane reinforced soil (PRS mixture was conducted. The UCS values over 3 MPa were measured from the PRS specimens. The testing results showed that treated soil can economically become a desirable rock-like material in terms of slake durability and resistances against freezing–thawing, impact effect and abrasion. As another characteristic of the rock-like material made with polyurethane foam, unit volume weight was found to be quite lower than those of natural rock materials.

  4. Effect of Zinc Phosphate on the Corrosion Behavior of Waterborne Acrylic Coating/Metal Interface.

    Science.gov (United States)

    Wan, Hongxia; Song, Dongdong; Li, Xiaogang; Zhang, Dawei; Gao, Jin; Du, Cuiwei

    2017-06-14

    Waterborne coating has recently been paid much attention. However, it cannot be used widely due to its performance limitations. Under the specified conditions of the selected resin, selecting the function pigment is key to improving the anticorrosive properties of the coating. Zinc phosphate is an environmentally protective and efficient anticorrosion pigment. In this work, zinc phosphate was used in modifying waterborne acrylic coatings. Moreover, the disbonding resistance of the coating was studied. Results showed that adding zinc phosphate can effectively inhibit the anode process of metal corrosion and enhance the wet adhesion of the coating, and consequently prevent the horizontal diffusion of the corrosive medium into the coating/metal interface and slow down the disbonding of the coating.

  5. Human waterborne parasites in zebra mussels ( Dreissena polymorpha) from the Shannon River drainage area, Ireland.

    Science.gov (United States)

    Graczyk, Thaddeus K; Conn, David Bruce; Lucy, Frances; Minchin, Dan; Tamang, Leena; Moura, Lacy N S; DaSilva, Alexandre J

    2004-08-01

    Zebra mussels ( Dreissena polymorpha) from throughout the Shannon River drainage area in Ireland were tested for the anthropozoonotic waterborne parasites Cryptosporidium parvum, Giardia lamblia, Encephalitozoon intestinalis, E. hellem, and Enterocytozoon bieneusi, by the multiplexed combined direct immunofluorescent antibody and fluorescent in situ hybridization method, and PCR. Parasite transmission stages were found at 75% of sites, with the highest mean concentration of 16, nine, and eight C. parvum oocysts, G. lamblia cysts, and Encephalitozoon intestinalis spores/mussel, respectively. On average eight Enterocytozoon bieneusi spores/mussel were recovered at any selected site. Approximately 80% of all parasites were viable and thus capable of initiating human infection. The Shannon River is polluted with serious emerging human waterborne pathogens including C. parvum, against which no therapy exists. Zebra mussels can recover and concentrate environmentally derived pathogens and can be used for the sanitary assessment of water quality.

  6. Implications of biofilm-associated waterborne Cryptosporidium oocysts for the water industry.

    Science.gov (United States)

    Angles, Mark L; Chandy, Joseph P; Cox, Peter T; Fisher, Ian H; Warnecke, Malcolm R

    2007-08-01

    Waterborne Cryptosporidium has been responsible for drinking water-associated disease outbreaks in a number of developed countries. As a result of the resistance of Cryptosporidium to chlorine, which is typically applied as a final barrier to protect the quality of distributed drinking water, current management practices are focused on source-water management and water treatment as ways of preventing Cryptosporidium from entering drinking-water supplies. In the event that treatment barriers fail, surprisingly little is known of the fate of oocysts once they enter a distribution system. To assess properly the risks of waterborne Cryptosporidium, a more thorough understanding of the fate of oocysts in water distribution systems, with emphasis on Cryptosporidium-biofilm interactions, is required.

  7. Addition of polyurethane dispersions to Portland G for oil wells steam injection submitted to vapor injection; Adicao de poliuretana em dispersao a Portland G para cimentacao de pocos de petroleo sujeitos a injecao de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Silva, L.B. da; Lima, F.M. de; Martinelli, A.M.; Bezerra, U.T.; Mello, D.M.A. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Araujo, R.G.S. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    Portland cement is by far the most important binding material used in oil well cementing. The cement sheath is responsible for both the mechanical stability of the wellbore and zonal isolation. During primary cementing and the production lifespan of the well, the cement sheath is exposed to adverse thermo-mechanical conditions, which may crack the intrinsically brittle cement material. Cracking affects the mechanical integrity of the sheath resulting in the contamination of oil or gas pay zones, as well as in the increase of producing costs related to the extraction of pebble and water. This scenario is especially encountered in wells containing heavy oils, typical of the Northeastern region of Brazil. The objective of the present study was to improve the fracture toughness of hardened Special Portland Cement slurries by the addition of aqueous polyurethane to Portland-based slurries used in primary cementing, plug backs and squeeze operations, improving environmental and economical impacts. The results revealed that the addition of polyurethane increased the viscosity of the slurry but still within the limits established by oil well cement guidelines. No significant increase was observed in the compressive strength of the cement. However, the addition of polyurethane improved the toughness of the cement increasing its ability to withstand thermo-mechanical cycles typical of heavy oil recovery. In addition, significant reduction in permeability was observed as the contents of polyurethane increased, contributing to the reduction in set time and gas migration through the cement sheath. (author)

  8. Water-borne hyphomycetes in tree canopies of Kaiga (Western Ghats, India

    Directory of Open Access Journals (Sweden)

    Naga M. Sudheep

    2013-12-01

    Full Text Available The canopy samples such as trapped leaf litter, trapped sediment (during summer, stemflow and throughfall (during monsoon from five common riparian tree species (Artocarpus heterophyllus, Cassia fistula, Ficus recemosa, Syzygium caryophyllatum and Xylia xylocarpa in Kaiga forest stand of the Western Ghats of southwest India were evaluated for the occurrence of water-borne hyphomycetes. Partially decomposed trapped leaf litter was incubated in bubble chambers followed by filtration to assess conidial output. Sediments accumulated in tree holes or junction of branches were shaken with sterile leaf disks in distilled water followed by incubation of leaf disks in bubble chamber and filtration to find out colonized fungi. Stemflow and throughfall samples were filtered directly to collect free conidia. From five canopy niches, a total of 29 water-borne hyphomycetes were recovered. The species richness was higher in stemflow and throughfall than trapped leaf litter and sediments (14-16 vs. 6-10 species. Although sediments of Syzygium caryophyllatum were acidic (5.1, the conidial output was higher than other tree species. Stemflow and throughfall of Xylea xylocarpa even though alkaline (8.5-8.7 showed higher species richness (6-12 species as well as conidial load than rest of the tree species. Flagellospora curvula and Triscelophorus acuminatus were common in trapped leaf litter and sediments respectively, while conidia of Anguillospora crassa and A. longissima were frequent in stemflow and throughfall. Diversity of water-borne hyphomycetes was highest in throughfall of Xylea xylocarpa followed by throughfall of Ficus recemosa. Our study reconfirms the occurrence and survival of diverse water-borne hyphomycetes in different niches of riparian tree canopies of the Western Ghats during wet and dry regimes and predicts their possible role in canopy as saprophytes, endophytes and alternation of life cycle between canopy and aquatic habitats.

  9. A review of outbreaks of waterborne disease associated with ships: evidence for risk management.

    Science.gov (United States)

    Rooney, Roisin M; Bartram, Jamie K; Cramer, Elaine H; Mantha, Stacey; Nichols, Gordon; Suraj, Rohini; Todd, Ewen C D

    2004-01-01

    The organization of water supply to and on ships differs considerably from that of water supply on land. Risks of contamination can arise from source water at the port or during loading, storage, or distribution on the ship. The purpose of this article is to review documented outbreaks of waterborne diseases associated with passenger, cargo, fishing, and naval ships to identify contributing factors so that similar outbreaks can be prevented in the future. The authors reviewed 21 reported outbreaks of waterborne diseases associated with ships. For each outbreak, data on pathogens/toxins, type of ship, factors contributing to outbreaks, mortality and morbidity, and remedial action are presented. The findings of this review show that the majority of reported outbreaks were associated with passenger ships and that more than 6,400 people were affected. Waterborne outbreaks due to Enterotoxigenic Escherichia coli, noroviruses, Salmonella spp, Shigella sp, Cryptosporidium sp, and Giardia lamblia occurred on ships. Enterotoxigenic E. coli was the pathogen most frequently associated with outbreaks. One outbreak of chemical water poisoning also occurred on a ship. Risk factors included contaminated port water, inadequate treatment, improper loading techniques, poor design and maintenance of storage tanks, ingress of contamination during repair and maintenance, cross-connections, back siphonage, and insufficient residual disinfectant. Waterborne disease outbreaks on ships can be prevented. The factors contributing to outbreaks emphasize the need for hygienic handling of water along the supply chain from source to consumption. A comprehensive approach to water safety on ships is essential. This may be achieved by the adoption of Water Safety Plans that cover design, construction, operation, and routine inspection and maintenance.

  10. Water and infection : Epidemiological studies of epidemic and endemic waterborne disease

    OpenAIRE

    Nygård, Karin

    2008-01-01

    Infections transmitted by water continue to be a public health problem both in developing and in developed countries. In the developed countries, the classical waterborne diseases such as typhoid and cholera are almost eliminated, whereas other pathogens and challenges have emerged. The overall aim of the thesis was to investigate and describe aspects of water-associated infections in a Nordic setting. Contaminated water may act as a transmitter of infectious disease by various routes. E...

  11. Environmentally friendly hybrid coatings for corrosion protection: silane based pre-treatments and nanostructured waterborne coatings

    OpenAIRE

    Fedel, Michele

    2009-01-01

    This thesis considers a nanotechnology approach based on the production of metals pre-treatments and organic coatings (a complete protection system at all) designed from the nanoscale. The final aim is to develop protection systems with improved corrosion protection properties and a low environmental impact. In particular, multifunctional silane hybrid molecules were used to design sol-gel pre-treatments for metals and to modify the inner structure of UV curable waterborne organic coatings...

  12. Aspergillosis in the common sea fan Gorgonia ventalina: isolation of waterborne hyphae and spores.

    Science.gov (United States)

    Troeger, Victoria J; Sammarco, Paul W; Caruso, John H

    2014-07-03

    The octocoral disease aspergillosis is caused by the terrestrial fungus Aspergillus sydowii. The possibility of secondary (horizontal) transmission of aspergillosis among common sea fans Gorgonia ventalina would require waterborne transmission of hyphae and/or spores. A laboratory filtration experiment confirmed that fungal hyphae and spores were shed into the water by infected fans. This suggests that secondary infection might be possible in this species. It remains to be determined whether healthy fans actually develop aspergillosis after contact with hyphae-laden water.

  13. Classification and prediction of river network ephemerality and its relevance for waterborne disease epidemiology

    Science.gov (United States)

    Perez-Saez, Javier; Mande, Theophile; Larsen, Joshua; Ceperley, Natalie; Rinaldo, Andrea

    2017-12-01

    The transmission of waterborne diseases hinges on the interactions between hydrology and ecology of hosts, vectors and parasites, with the long-term absence of water constituting a strict lower bound. However, the link between spatio-temporal patterns of hydrological ephemerality and waterborne disease transmission is poorly understood and difficult to account for. The use of limited biophysical and hydroclimate information from otherwise data scarce regions is therefore needed to characterize, classify, and predict river network ephemerality in a spatially explicit framework. Here, we develop a novel large-scale ephemerality classification and prediction methodology based on monthly discharge data, water and energy availability, and remote-sensing measures of vegetation, that is relevant to epidemiology, and maintains a mechanistic link to catchment hydrologic processes. Specifically, with reference to the context of Burkina Faso in sub-Saharan Africa, we extract a relevant set of catchment covariates that include the aridity index, annual runoff estimation using the Budyko framework, and hysteretical relations between precipitation and vegetation. Five ephemerality classes, from permanent to strongly ephemeral, are defined from the duration of 0-flow periods that also accounts for the sensitivity of river discharge to the long-lasting drought of the 70's-80's in West Africa. Using such classes, a gradient-boosted tree-based prediction yielded three distinct geographic regions of ephemerality. Importantly, we observe a strong epidemiological association between our predictions of hydrologic ephemerality and the known spatial patterns of schistosomiasis, an endemic parasitic waterborne disease in which infection occurs with human-water contact, and requires aquatic snails as an intermediate host. The general nature of our approach and its relevance for predicting the hydrologic controls on schistosomiasis occurrence provides a pathway for the explicit inclusion of

  14. Rainfall-runoff model for prediction of waterborne viral contamination in a small river catchment

    Science.gov (United States)

    Gelati, E.; Dommar, C.; Lowe, R.; Polcher, J.; Rodó, X.

    2013-12-01

    We present a lumped rainfall-runoff model aimed at providing useful information for the prediction of waterborne viral contamination in small rivers. Viral contamination of water bodies may occur because of the discharge of sewage effluents and of surface runoff over areas affected by animal waste loads. Surface runoff is caused by precipitation that cannot infiltrate due to its intensity and to antecedent soil water content. It may transport animal feces to adjacent water bodies and cause viral contamination. We model streamflow by separating it into two components: subsurface flow, which is produced by infiltrated precipitation; and surface runoff. The model estimates infiltrated and non-infiltrated precipitation and uses impulse-response functions to compute the corresponding fractions of streamflow. The developed methodologies are applied to the Glafkos river, whose catchment extends for 102 km2 and includes the city of Patra. Streamflow and precipitation observations are available at a daily time resolution. Waterborne virus concentration measurements were performed approximately every second week from the beginning of 2011 to mid 2012. Samples were taken at several locations: in river water upstream of Patras and in the urban area; in sea water at the river outlet and approximately 2 km south-west of Patras; in sewage effluents before and after treatment. The rainfall-runoff model was calibrated and validated using observed streamflow and precipitation data. The model contribution to waterborne viral contamination prediction was benchmarked by analyzing the virus concentration measurements together with the estimated surface runoff values. The presented methodology may be a first step towards the development of waterborne viral contamination alert systems. Predicting viral contamination of water bodies would benefit sectors such as water supply and tourism.

  15. River Networks As Ecological Corridors for Species, Populations and Pathogens of Water-Borne Disease

    Science.gov (United States)

    Rinaldo, A.

    2014-12-01

    River basins are a natural laboratory for the study of the integration of hydrological, ecological and geomorphological processes. Moving from morphological and functional analyses of dendritic geometries observed in Nature over a wide range of scales, this Lecture addresses essential ecological processes that take place along dendritic structures, hydrology-driven and controlled, like e.g.: population migrations and human settlements, that historically proceeded along river networks to follow water supply routes; riparian ecosystems composition that owing to their positioning along streams play crucial roles in their watersheds and in the loss of biodiversity proceeding at unprecedented rates; waterborne disease spreading, like epidemic cholera that exhibits epidemic patterns that mirror those of watercourses and of human mobility and resurgences upon heavy rainfall. Moreover, the regional incidence of Schistosomiasis, a parasitic waterborne disease, and water resources developments prove tightly related, and proliferative kidney disease in fish thrives differently in pristine and engineered watercourses: can we establish quantitatively the critical linkages with hydrologic drivers and controls? How does connectivity within a river network affect community composition or the spreading mechanisms? Does the river basin act as a template for biodiversity or for species' persistence? Are there hydrologic controls on epidemics of water-borne disease? Here, I shall focus on the noteworthy scientific perspectives provided by spatially explicit eco-hydrological studies centered on river networks viewed as ecological corridors for species, populations and pathogens of waterborne disease. A notable methodological coherence is granted by the mathematical description of river networks as the support for reactive transport. The Lecture overviews a number of topics idiosyncratically related to my own research work but ideally aimed at a coherent body of materials and methods. A

  16. Infected Donor Biomass and Active Feeding Increase Waterborne Transmission of Ichthyophonus sp. to Rainbow Trout Sentinels.

    Science.gov (United States)

    LaPatra, S E; Kocan, R M

    2016-06-01

    The precise nature of Ichthyophonus sp. transmission among wild fishes has eluded description for over a century. Transmission among piscivores is direct, via ingestion of infected prey, but there is also evidence for waterborne transmission between infected and uninfected individuals. Transmission among planktivores is believed to be via a waterborne infectious cell, but definitive proof of this mechanism has not been forthcoming. To explore possible mechanisms of transmission we used Rainbow Trout Oncorhynchus mykiss as a model system and examined the consequence of housing infected donor fish with uninfected (sentinel) fish, without physical contact. We examined two variables linked to transmission: (1) feeding and nonfeeding sentinel fish, and (2) biomass of infected donor fish. Specific-pathogen free sentinel trout were placed in fine-mesh baskets suspended in tanks containing varying numbers of larger Ichthyophonus-infected donor fish and held for 10 weeks, during which time they were examined by in vitro explant culture for the presence of Ichthyophonus. Treatment groups consisted of fed and unfed sentinels housed with infected donors of increasing biomass. After 10 weeks infection prevalence in fed sentinels was significantly higher than in unfed sentinels, and Ichthyophonus was detected earlier in fed fish than in unfed fish. There was no correlation between infection prevalence and donor biomass in fed sentinels, but there was a strong correlation between infection prevalence and increasing donor biomass in unfed sentinels. These data suggest that Ichthyophonus is maintained in wild fish populations by two distinct mechanisms: (1) waterborne infectious cells ingested directly from the water by planktivores, and (2) both infected prey and waterborne infectious cells ingested by piscivores. Received November 13, 2015; accepted February 13, 2016.

  17. Decreased waterborne pathogenic bacteria in an urban aquifer related to intense shallow geothermal exploitation.

    Science.gov (United States)

    García-Gil, Alejandro; Gasco-Cavero, Samanta; Garrido, Eduardo; Mejías, Miguel; Epting, Jannis; Navarro-Elipe, Mercedes; Alejandre, Carmen; Sevilla-Alcaine, Elena

    2018-08-15

    The implications of intensive use of shallow geothermal energy resources in shallow urban aquifers are still not known for waterborne pathogens relevant to human health. Firstly, we hypothesized that waterborne enteric pathogens would be relatively increased in heated groundwater plumes. To prove this, microbiological sampling of 31 piezometers covering the domain of an urban groundwater body affected by microbiological contamination and energetically exploited by 70 groundwater heat pump systems was performed. Mean differences of pathogenic bacteria contents between impacted and non-impacted monitoring points were assessed with a two-tailed independent Student's t-test or Mann-Whitney U and correlation coefficients were also calculated. Surprisingly, the results obtained revealed a significant and generalized decrease in waterborne pathogen contents in thermally impacted piezometers compared to that of non-impacted piezometers. This decrease is hypothesized to be caused by a heat shock to bacteria within the heat exchangers. The statistically significant negative correlations obtained between waterborne pathogen counts and temperature could be explained by the spatial distribution of the bacteria, finding that bacteria start to recover with increasing distance from the injection point. Also, different behavior groups fitting exponential regression models were found for the bacteria species studied, justified by the different presence and influence of several aquifer parameters and major, minor and trace elements studied, as well as the coexistence with other bacteria species. The results obtained from this work reinforce the concept of shallow geothermal resources as a clean energy source, as they could also provide the basis to control the pathogenic bacteria contents in groundwater bodies. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Polyurethane-Coated Breast Implants Revisited: A 30-Year Follow-Up

    Directory of Open Access Journals (Sweden)

    Nikki Castel

    2015-03-01

    Full Text Available BackgroundPolyurethane coating of breast implants has been shown to reduce capsular contracture in short-term follow-up studies. This 30-year study is the longest examination of the use of polyurethane-coated implants and their correlation with capsular contracture.MethodsThis study evaluates the senior surgeon's (F.D.P. experience with the use of polyurethane-coated implants in aesthetic breast augmentation in 382 patients over 30 years. Follow-up evaluations were conducted for six months after surgery. After the six-month follow-up period, 76 patients returned for reoperation. The gross findings, histology, and associated capsular contracture were noted at the time of explantation.ResultsNo patient during the six-month follow-up period demonstrated capsular contracture. For those who underwent reoperation for capsular contracture, Baker II/III contractures were noted nine to 10 years after surgery and Baker IV contractures were noted 12 to 21 years after surgery. None of the explanted implants had macroscopic evidence of polyurethane, which was only found during the first five years after surgery. The microscopic presence of polyurethane was noted in all capsules up to 30 years after the original operation.ConclusionsAn inverse correlation was found between the amount of polyurethane coating on the implant and the occurrence of capsular contracture. Increasingly severe capsular contracture was associated with a decreased amount of polyurethane coating on the surface of the implants. No contracture occurred in patients whose implants showed incomplete biodegradation of polyurethane, as indicated by the visible presence of polyurethane coating. We recommend research to find a non-toxic, non-biodegradable synthetic material as an alternative to polyurethane.

  19. Corrosion protection performance of waterborne epoxy coatings containing self-doped polyaniline nanofiber

    International Nuclear Information System (INIS)

    Qiu, Shihui; Chen, Cheng; Cui, Mingjun; Li, Wei; Zhao, Haichao; Wang, Liping

    2017-01-01

    Highlights: • Self-dopedpolyaniline (SPANi) with good conductivity and dispersibility in water was copolymerized by aniline and its derivative. • Environmental friendly SPANi/epoxy composite coating with remarkable anti-corrosion performance was prepared. • The corrosion product of pure epoxy or composite coating was characterized by X-ray diffraction pattern and scanning electron microscope (SEM). - Abstract: Self-doped sulfonated polyaniline (SPANi) nanofiber was synthesized by the copolymerization of 2-aminobenzenesulfonic acid (ASA) and aniline via a rapid mixing polymerization approach. The chemical structure of SPANi was investigated by the Fourier-transform infrared (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), UV–vis spectra and X-ray diffraction (XRD) pattern. The as-prepared SPANi nanofibers had 45 nm average diameter and length up to 750 nm as measured by scanning electron microscope (SEM) and transmission electron microscope (TEM). The self-doped SPANi nanofiber possessed excellent aqueous solubility, good conductivity (0.11 S/cm) and reversible redox activity, making it suitable as a corrosion inhibitor for waterborne coatings. The prepared SPANi/waterborne epoxy composite coatings exhibited remarkably improved corrosion protection compared with pure waterborne epoxy coating as proved by the polarization curves and electrochemical impedance spectroscopy (EIS). The passivation effect of SPANi nanofiber and the corrosion products beneath the epoxy coatings immersed in 3.5% NaCl solution as a function of time were also investigated in this study.

  20. Competence in water-borne heating systems in buildings; Kompetanse innen vannbaarene varmesystemer i bygg

    Energy Technology Data Exchange (ETDEWEB)

    Jarstein, Stig; Palm, Linn Therese; Naess, Bente Haukland; Nossum, Aase; Johnsen, Morten

    2009-01-15

    Trade participants in water-borne heating systems in buildings has experienced mistakes in all phases and of all participants of a project. When water-borne heating system functions, there is almost no follow up. This report is based on a qualitative survey where a several central participants, who on a daily basis are involved in projects with water-borne heating systems, are interviewed or have participated in focus group meetings. Following points illustrate experiences made by the operators in occasions where competence in trade is insufficiencies and mistakes occur: - Property developer lacks ordering competence and has problems in ordering quality. Consultant submit services of minor quality. Performance is of another quality than the supplier. Administration / maintenance lacks competence in how to run the system and without introduction and training in the heating system they take over a system that is over dimensioned and hard to regulate. The trade as a whole knows all the challenges, but the participants gives mainly the impression that the fault is lac of competence for all the other participants - not them self. This report points out measures and Enova can support competence improving measures which on long term will improve the quality from the participants. The trade is recommended to look into project execution, how competence is involved at the right moment, improving of control and documentation routines and at termination / hand over. (AG).14 refs., 14 figs., 2 tabs

  1. Corrosion protection performance of waterborne epoxy coatings containing self-doped polyaniline nanofiber

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Shihui [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211 (China); Chen, Cheng; Cui, Mingjun [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Li, Wei [Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211 (China); Zhao, Haichao, E-mail: zhaohaichao@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Wang, Liping, E-mail: wangliping@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China)

    2017-06-15

    Highlights: • Self-dopedpolyaniline (SPANi) with good conductivity and dispersibility in water was copolymerized by aniline and its derivative. • Environmental friendly SPANi/epoxy composite coating with remarkable anti-corrosion performance was prepared. • The corrosion product of pure epoxy or composite coating was characterized by X-ray diffraction pattern and scanning electron microscope (SEM). - Abstract: Self-doped sulfonated polyaniline (SPANi) nanofiber was synthesized by the copolymerization of 2-aminobenzenesulfonic acid (ASA) and aniline via a rapid mixing polymerization approach. The chemical structure of SPANi was investigated by the Fourier-transform infrared (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), UV–vis spectra and X-ray diffraction (XRD) pattern. The as-prepared SPANi nanofibers had 45 nm average diameter and length up to 750 nm as measured by scanning electron microscope (SEM) and transmission electron microscope (TEM). The self-doped SPANi nanofiber possessed excellent aqueous solubility, good conductivity (0.11 S/cm) and reversible redox activity, making it suitable as a corrosion inhibitor for waterborne coatings. The prepared SPANi/waterborne epoxy composite coatings exhibited remarkably improved corrosion protection compared with pure waterborne epoxy coating as proved by the polarization curves and electrochemical impedance spectroscopy (EIS). The passivation effect of SPANi nanofiber and the corrosion products beneath the epoxy coatings immersed in 3.5% NaCl solution as a function of time were also investigated in this study.

  2. Waterborne disease-related risk perceptions in the Sonora River basin, Mexico.

    Science.gov (United States)

    Morua, Agustin Robles; Halvorsen, Kathleen E; Mayer, Alex S

    2011-05-01

    Waterborne disease is estimated to cause about 10% of all diseases worldwide. However, related risk perceptions are not well understood, particularly in the developing world where waterborne disease is an enormous problem. We focus on understanding risk perceptions related to these issues in a region within northern Mexico. Our findings show how waterborne disease problems and solutions are understood in eight small communities along a highly contaminated river system. We found major differences in risk perceptions between health professionals, government officials, and lay citizens. Health professionals believed that a high level of human-waste-related risk existed within the region. Few officials and lay citizens shared this belief. In addition, few officials and lay citizens were aware of poor wastewater-management-related disease outbreaks and water contamination. Finally, aside from health professionals, a few interviewees understood the importance of basic hygiene and water treatment measures that could help to prevent disease. Our results add to the literature on environmentally-related risk perceptions in the developing world. We discuss recommendations for improving future human-wastewater-related risk communication within the region. © 2011 Society for Risk Analysis.

  3. Copper uptake kinetics and regulation in a marine fish after waterborne copper acclimation

    International Nuclear Information System (INIS)

    Dang Fei; Zhong Huan; Wang Wenxiong

    2009-01-01

    The uptake kinetics and regulation of copper in a marine predatory fish, the black sea bream Acanthopagrus schlegeli after acclimation to waterborne Cu were examined, using radiotracer techniques. The dissolved Cu uptake followed a linear pattern during the time of exposure, and the calculated uptake rate constant was 6.24 L kg -1 day -1 . The efflux rate constant was 0.091 day -1 following dietary uptake of Cu, and the dietary assimilation efficiency (AE) of Cu varied between 1.7% and 10.9% after the fish were fed with three types of prey (oysters, clams and brine shrimp). After the fish were acclimated at a nominal concentration of 50 μg Cu L -1 for 14 days, the Cu uptake rate and efflux rate constant did not change significantly, but the Cu body concentrations and metallothionein (MT) concentrations in fish tissues increased significantly. Subcellular Cu distributions were also modified. Significant MT induction was observed in response to increased Cu tissue concentrations, indicating that MT rather than the uptake kinetics may play a primary role in Cu regulation during waterborne Cu acclimation in this marine fish. Moreover, the high Cu efflux may also be important in Cu regulation during long-term exposure. Our modeling calculations indicated that dietary uptake was likely to be the main route for Cu bioaccumulation in the fish, and the relative contribution of waterborne and dietary uptake depended on the bioconcentration factor (BCF) of the prey and ingestion rate of fish.

  4. Probabilistic risk assessment of abalone Haliotis diversicolor supertexta exposed to waterborne zinc

    International Nuclear Information System (INIS)

    Liao Chungmin; Ling Minpei

    2004-01-01

    This paper describes a risk assessment approach that integrates predicted tissue concentrations of zinc (Zn) with a concentration-response relationship and leads to predictions of survival risk for pond abalone Haliotis diversicolor supertexta as well as to the uncertainties associated with these predictions. The models implemented include a probabilistic bioaccumulation model, which linking biokinetic and consumer-resource models, accounts for Zn exposure profile and a modified Hill model for reconstructing a dose-response profile for abalone exposed to waterborne Zn. The growth risk is assessed by hazard quotients characterized by measured water level and chronic no-observed effect concentration. Our risk analyses for H. diversicolor supertexta reared near Toucheng, Kouhu, and Anping, respectively, in north, central, and south Taiwan region indicate a relatively low likelihood that survival is being affected by waterborne Zn. Expected risks of mortality for abalone were estimated as 0.46 (Toucheng), 0.36 (Kouhu), and 0.29 (Anping). The predicted 90th-percentiles of hazard quotient for potential growth risk were estimated as 1.94 (Toucheng), 0.47 (Kouhu), and 0.51 (Anping). These findings indicate that waterborne Zn exposure poses no significant risk to pond abalone in Kouhu and Anping, yet a relative high growth risk in Toucheng is alarming. Because of a scarcity of toxicity and exposure data, the probabilistic risk assessment was based on very conservative assumptions. - A novel risk assessment method was developed for abalone

  5. Probabilistic risk assessment of abalone Haliotis diversicolor supertexta exposed to waterborne zinc

    Energy Technology Data Exchange (ETDEWEB)

    Liao Chungmin; Ling Minpei

    2004-01-01

    This paper describes a risk assessment approach that integrates predicted tissue concentrations of zinc (Zn) with a concentration-response relationship and leads to predictions of survival risk for pond abalone Haliotis diversicolor supertexta as well as to the uncertainties associated with these predictions. The models implemented include a probabilistic bioaccumulation model, which linking biokinetic and consumer-resource models, accounts for Zn exposure profile and a modified Hill model for reconstructing a dose-response profile for abalone exposed to waterborne Zn. The growth risk is assessed by hazard quotients characterized by measured water level and chronic no-observed effect concentration. Our risk analyses for H. diversicolor supertexta reared near Toucheng, Kouhu, and Anping, respectively, in north, central, and south Taiwan region indicate a relatively low likelihood that survival is being affected by waterborne Zn. Expected risks of mortality for abalone were estimated as 0.46 (Toucheng), 0.36 (Kouhu), and 0.29 (Anping). The predicted 90th-percentiles of hazard quotient for potential growth risk were estimated as 1.94 (Toucheng), 0.47 (Kouhu), and 0.51 (Anping). These findings indicate that waterborne Zn exposure poses no significant risk to pond abalone in Kouhu and Anping, yet a relative high growth risk in Toucheng is alarming. Because of a scarcity of toxicity and exposure data, the probabilistic risk assessment was based on very conservative assumptions. - A novel risk assessment method was developed for abalone.

  6. Improved lignin polyurethane properties with Lewis acid treatment.

    Science.gov (United States)

    Chung, Hoyong; Washburn, Newell R

    2012-06-27

    Chemical modification strategies to improve the mechanical properties of lignin-based polyurethanes are presented. We hypothesized that treatment of lignin with Lewis acids would increase the concentration of hydroxyl groups available to react with diisocyanate monomers. Under the conditions used, hydrogen bromide-catalyzed modification resulted in a 28% increase in hydroxyl group content. Associated increases in hydrophilicity of solvent-cast thin films were also recorded as evidenced by decreases in water contact angle. Polyurethanes were then prepared by first preparing a prepolymer based on mixtures of toluene-2,4-diisocyanate (TDI) and unmodified or modified lignin, then polymerization was completed through addition of polyethylene glycol (PEG), resulting in mass ratios of TDI:lignin:PEG of 43:17:40 in the compositions investigated here. The mixture of TDI and unmodified lignin resulted in a lignin powder at the bottom of the liquid, suggesting it did not react directly with TDI. However, a homogeneous solution resulted when TDI and the hydrogen bromide-treated lignin were mixed, suggesting demethylation indeed increased reactivity and resulted in better integration of lignin into the urethane network. Significant improvements in mechanical properties of modified lignin polyurethanes were observed, with a 6.5-fold increase in modulus, which were attributed to better integration of the modified lignin into the covalent polymer network due to the higher concentration of hydroxyl groups. This research indicates that chemical modification strategies can lead to significant improvements in the properties of lignin-based polymeric materials using a higher fraction of an inexpensive lignin monomer from renewable resources and a lower fraction an expensive, petroleum-derived isocyanate monomer to achieve the required material properties.

  7. Dielectric and conductivity properties of composite polyaniline/polyurethane network

    Science.gov (United States)

    Liang, C.; Gest, J.; Leroy, G.; Carru, J.-C.

    2013-09-01

    In this work, we present the dielectric characterization of polyaniline/polyurethane composite. The samples consisting of 0.5%, 1%, and 5% of polyaniline were deposited on glass fiber, and the measurements were performed in a frequency range of 20 Hz to 20 GHz. The results showed a dielectric relaxation strongly dependent on the concentration of polyaniline. This phenomenon is explained by a theoretical model. In this model, we assume that the alternative conductivity of the polymer network systems is due to conducting clusters whose lengths followed a Gaussian distribution. Depending on their size and the frequency of the excitation signal, the clusters showed a resistive or capacitive effect.

  8. Investigation of Industrial Polyurethane Foams Modified with Antimicrobial Copper Nanoparticles

    Directory of Open Access Journals (Sweden)

    Maria Chiara Sportelli

    2016-07-01

    Full Text Available Antimicrobial copper nanoparticles (CuNPs were electrosynthetized and applied to the controlled impregnation of industrial polyurethane foams used as padding in the textile production or as filters for air conditioning systems. CuNP-modified materials were investigated and characterized morphologically and spectroscopically, by means of Transmission Electron Microscopy (TEM, and X-ray Photoelectron Spectroscopy (XPS. The release of copper ions in solution was studied by Electro-Thermal Atomic Absorption Spectroscopy (ETAAS. Finally, the antimicrobial activity of freshly prepared, as well as aged samples—stored for two months—was demonstrated towards different target microorganisms.

  9. Stretchable polyurethane sponge reinforced magnetorheological material with enhanced mechanical properties

    International Nuclear Information System (INIS)

    Ge, Lin; Xuan, Shouhu; Liao, Guojiang; Yin, Tiantian; Gong, Xinglong

    2015-01-01

    A stretchable magnetorheological material (SMRM) consisting of micro-meter carbonyl iron (CI) particles, low cross-linking polyurethane (PU) polymer and porous PU sponge has been developed. Due to the presence of the PU sponge, the high-performance MR material can be reversibly stretched or bent, just as MR elastomers. When the CI content increases to 80 wt%, the magnetic induced modulus of the MR material can reach as high as 7.34 MPa and the corresponding relative MR effect increases to 820%. A possible strengthening mechanism of the SMRM was proposed. The attractive mechanical properties make the SMRM a promising candidate for future high-performance devices. (technical note)

  10. Method for providing a low density high strength polyurethane foam

    Science.gov (United States)

    Whinnery, Jr., Leroy L.; Goods, Steven H.; Skala, Dawn M.; Henderson, Craig C.; Keifer, Patrick N.

    2013-06-18

    Disclosed is a method for making a polyurethane closed-cell foam material exhibiting a bulk density below 4 lbs/ft.sup.3 and high strength. The present embodiment uses the reaction product of a modified MDI and a sucrose/glycerine based polyether polyol resin wherein a small measured quantity of the polyol resin is "pre-reacted" with a larger quantity of the isocyanate in a defined ratio such that when the necessary remaining quantity of the polyol resin is added to the "pre-reacted" resin together with a tertiary amine catalyst and water as a blowing agent, the polymerization proceeds slowly enough to provide a stable foam body.

  11. Electron beam curing polyurethane acrylate oligomer in air

    International Nuclear Information System (INIS)

    Zhu, Zhenkang; Chen, Xing; Zhou, Jichun; Ma, Zue-Teh

    1988-01-01

    It has been found according to our synthesis that a novel kind of polyurethane acrylate oligomer can be cured by electron beam in the presence of oxygen, even at normal atomospheric levels, without any additives. Irradiation of the oligomer with substantially complete cure to a solid non-tacky state is quite remarkable. It has the same gel content (90 %) in air as in nitrogen at dose of 33 kGy. Double bond conversion of the oligomer is about 50 % by I.R. (author)

  12. Radiation-induced changes affecting polyester based polyurethane binder

    Science.gov (United States)

    Pierpoint, Sujita Basi

    The application of thermoplastic polyurethane elastomers as binders in the high energy explosives particularly when used in weapons presents a significantly complex and challenging problem due to the impact of the aging of this polymer on the useful service life of the explosive. In this work, the effects of radiation on the aging of the polyester based polyurethane were investigated using both electron beam and gamma irradiation at various dose rates in the presence and absence of oxygen. It was found by means of GPC that, in the presence and absence of oxygen, the poly (ester urethane) primarily undergoes cross-linking, by means of a carbon-centered secondary alkyl radical. It was also concluded that the polymer partially undergoes scission of the backbone of the main chain at C-O, N-C, and C-C bonds. Substantial changes in the conditions of irradiation and in dose levels did not affect the cross-linking and scission yields. Experiments were also performed with EPR spectroscopy for the purpose of identifying the initial carbon-centered free radicals and for studying the decay mechanisms of these radicals. It was found that the carbon-centered radical which is produced via C-C scission (primary alkyl radical) is rapidly converted to a long-lived allylic species at higher temperatures; more than 80% radicals are converted to allyl species in 2.5 hours. In the presence of oxygen, the allyl radical undergoes a fast reaction to produce a peroxyl radical; this radical decays with a 1.7 hour half-life by pseudo first-order kinetics to negligible levels in 13 hours. FTIR measurements were conducted to identify the radiation-induced changes to the functional groups in the polyester polyurethane. These measurements show an increase in carbonyl, amine and carboxylic groups as a result of reaction of H atoms with R-C-O·, ·NH-R and R-COO·. The FTIR results also demonstrate the production of the unsaturation resulting from hydrogen atom transfer during intrachain conversion

  13. New insights into polyurethane biodegradation and realistic prospects for the development of a sustainable waste recycling process.

    Science.gov (United States)

    Cregut, Mickael; Bedas, M; Durand, M-J; Thouand, G

    2013-12-01

    Polyurethanes are polymeric plastics that were first used as substitutes for traditional polymers suspected to release volatile organic hazardous substances. The limitless conformations and formulations of polyurethanes enabled their use in a wide variety of applications. Because approximately 10 Mt of polyurethanes is produced each year, environmental concern over their considerable contribution to landfill waste accumulation appeared in the 1990s. To date, no recycling processes allow for the efficient reuse of polyurethane waste due to their high resistance to (a)biotic disturbances. To find alternatives to systematic accumulation or incineration of polyurethanes, a bibliographic analysis was performed on major scientific advances in the polyurethane (bio)degradation field to identify opportunities for the development of new technologies to recondition this material. Until polymers exhibiting oxo- or hydro-biodegradative traits are generated, conventional polyurethanes that are known to be only slightly biodegradable are of great concern. The research focused on polyurethane biodegradation highlights recent attempts to reprocess conventional industrial polyurethanes via microbial or enzymatic degradation. This review describes several wonderful opportunities for the establishment of new processes for polyurethane recycling. Meeting these new challenges could lead to the development of sustainable management processes involving polymer recycling or reuse as environmentally safe options for industries. The ability to upgrade polyurethane wastes to chemical compounds with a higher added value would be especially attractive. © 2013.

  14. A Novel Biodegradable Polyurethane Matrix for Auricular Cartilage Repair: An In Vitro and In Vivo Study.

    Science.gov (United States)

    Iyer, Kartik; Dearman, Bronwyn L; Wagstaff, Marcus J D; Greenwood, John E

    2016-01-01

    Auricular reconstruction poses a challenge for reconstructive and burns surgeons. Techniques involving cartilage tissue engineering have shown potential in recent years. A biodegradable polyurethane matrix developed for dermal reconstruction offers an alternative to autologous, allogeneic, or xenogeneic biologicals for cartilage reconstruction. This study assesses such a polyurethane matrix for this indication in vivo and in vitro. To evaluate intrinsic cartilage repair, three pigs underwent auricular surgery to create excisional cartilage ± perichondrial defects, measuring 2 × 3 cm in each ear, into which acellular polyurethane matrices were implanted. Biopsies were taken at day 28 for histological assessment. Porcine chondrocytes ± perichondrocytes were cultured and seeded in vitro onto 1 × 1 cm polyurethane scaffolds. The total culture period was 42 days; confocal, histological, and immunohistochemical analyses of scaffold cultures were performed on days 14, 28, and 42. In vivo, the polyurethane matrices integrated with granulation tissue filling all biopsy samples. Minimal neocartilage invasion was observed marginally on some samples. Tissue composition was identical between ears whether perichondrium was left intact, or not. In vitro, the polyurethane matrix was biocompatible with chondrocytes ± perichondrocytes and supported production of extracellular matrix and Type II collagen. No difference was observed between chondrocyte culture alone and chondrocyte/perichondrocyte scaffold coculture. The polyurethane matrix successfully integrated into the auricular defect and was a suitable scaffold in vitro for cartilage tissue engineering, demonstrating its potential application in auricular reconstruction.

  15. Nano-TiO2/polyurethane composites for antibacterial and self-cleaning coatings

    International Nuclear Information System (INIS)

    Charpentier, P A; Burgess, K; Wang, L; Chowdhury, R R; Lotus, A F; Moula, G

    2012-01-01

    Grafting from polymerization was used to synthesize nano-titania/polyurethane (nTiO 2 /polyurethane) composite coatings, where nTiO 2 was chemically attached to the backbone of the polyurethane polymer matrix with a bifunctional monomer, 2,2-bis(hydroxymethyl) propionic acid (DMPA). This bifunctional monomer can coordinate to nTiO 2 through an available –COOH group, with two available hydroxyl groups that can react with diisocyanate terminated pre-polyurethane through step-growth polymerization. The coordination reaction was monitored by FTIR and TGA, with the coordination reaction found to follow first order kinetics. After step-growth polymerization, the polyurethane nanocomposites were found to be stable on standing with excellent distribution of Ti in the polymer matrix without any significant agglomeration compared to simple physical mixtures of nTiO 2 in the polyurethane coatings. The functionalized nTiO 2 –polyurethane composite coatings showed excellent antibacterial activity against gram-negative bacteria Escherichia coli; 99% of E. coli were killed within less than one hour under solar irradiation. Self-cleaning was also demonstrated using stearic acid as a model for ‘dirt’. (paper)

  16. Thermal assault and polyurethane foam-evaluating protective mechanisms

    International Nuclear Information System (INIS)

    Williamson, C.L.; Iams, Z.L.

    2004-01-01

    Rigid polyurethane foam utilizes a variety of mechanisms to mitigate the thermal assault of a ''regulatory burn''. Polymer specific heat and foam k-factor are of limited usefulness in predicting payload protection. Properly formulated rigid polyurethane foam provides additional safeguards by employing ablative mechanisms which are effective even when the foam has been crushed or fractured as a result of trauma. The dissociative transitions from polymer to gas and char, and the gas transport of heat from inside the package out into the environment are also thermal mitigators. Additionally, the in-situ production of an intumescent, insulative, carbonaceous char, confers thermal protection even when a package's outer steel skin has been breached. In this test program, 19 liter, ''Five gallon'' steel pails are exposed on one end to the flame of an ''Oil Burner'' as described in the US Federal Aviation Administration (FAA) ''Aircraft Materials Fire Test Handbook''. When burning 2 diesel at a nominal rate of 8.39 kg (18.5 pounds)/hr, the burner generates a high emissivity flame that impinges on the pail face with the thermal intensity of a full scale pool-fire environment. Results of these tests, TGA and MDSC analysis on the subject foams are reported, and their relevance to full size packages and pool fires are discussed

  17. Stem cell responses to plasma surface modified electrospun polyurethane scaffolds.

    Science.gov (United States)

    Zandén, Carl; Hellström Erkenstam, Nina; Padel, Thomas; Wittgenstein, Julia; Liu, Johan; Kuhn, H Georg

    2014-07-01

    The topographical effects from functional materials on stem cell behavior are currently of interest in tissue engineering and regenerative medicine. Here we investigate the influence of argon, oxygen, and hydrogen plasma surface modification of electrospun polyurethane fibers on human embryonic stem cell (hESC) and rat postnatal neural stem cell (NSC) responses. The plasma gases were found to induce three combinations of fiber surface functionalities and roughness textures. On randomly oriented fibers, plasma treatments lead to substantially increased hESC attachment and proliferation as compared to native fibers. Argon plasma was found to induce the most optimal combination of surface functionality and roughness for cell expansion. Contact guided migration of cells and alignment of cell processes were observed on aligned fibers. Neuronal differentiation around 5% was found for all samples and was not significantly affected by the induced variations of surface functional group distribution or individual fiber topography. In this study the influence of argon, oxygen, and hydrogen plasma surface modification of electrospun polyurethane fibers on human embryonic stem cell and rat postnatal neural stem cell (NSC) responses is studied with the goal of clarifying the potential effects of functional materials on stem cell behavior, a topic of substantial interest in tissue engineering and regenerative medicine. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Preparation and characterization of polyurethane microcapsules containing functional oil

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.H.; Seo, J.B.; Kim, Y.J. [Sungkyunkwan University, Suwon (Korea)

    2002-05-01

    Polyurethane microcapsules containing functional oil (citronella oil) were successfully prepared by conventional interfacial polymerization of tolulene 2,4-diisocyanate (TDI) and ethylene glycol (EG) and characterized by Fourier transform (FT-IR) spectroscopy, Ultraviolet spectroscopy, particle size analysis, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The effects of polymerization variables such as surfactant concentration and agitation speed, on the particle size and particle size distribution were investigated. FT-IR spectroscopic data showed that citronella oil was successfully encapsulated in the microcapsule. Thermogravimetric analysis data showed that the microcapsule was thermally stable up to 220 deg. C. The controlled release of the citronella oil present in the microcapsule core in a methanol medium was demonstrated by ultraviolet spectroscopy, showing that the amount of released citronella oil was increased with increasing time. It was observed that the amount of released citronella oil was increased with increasing stirring speed and emulsifier concentration in the microcapsule preparation step. Polyurethane microcapsules containing citronella oil showed excellent anti-moth property. (author). 28 refs., 1 tab., 12 figs.

  19. Corrosion Prevention of Aluminum Nanoparticles by a Polyurethane Coating.

    Science.gov (United States)

    Nishimura, Toshiyasu; Raman, Vedarajan

    2014-06-19

    In order to prevent corrosion, aluminum nanoparticles were coated with a polyurethane polymer. The coverage of the polyurethane polymer was controlled from 0 to 100%, which changed the corrosion rate of the nanoparticles quantitatively. The surface of the polymer coating was investigated by Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM), and the corrosion resistance of the nanoparticles was estimated by a wet/dry corrosion test on a Pt plate with a NaCl solution. From a TEM with EDAX analysis, the 10 mass% polymer coated Al particles in the synthesis were almost 100% covered on the surface by a polymer film of 10 nm thick. On the other hand, the 3 mass% polymer coated Al was almost 40% covered by a film. In the AFM, the potential around the Al particles had a relatively low value with the polymer coating, which indicated that the conductivity of the Al was isolated from the Pt plate by the polymer. Both the corrosion and H₂ evolution reaction rates were quantitatively reduced by the mass% of polymer coating. In the case of the 10 mass% coated sample, there was no corrosion of Al nanoparticles. This fact suggested that the electrochemical reaction was suppressed by the polymer coating. Moreover, the reaction rate of Al nanoparticles was suppressed in proportion to the coverage percentage of the coating. Thus, to conclude, it was found that the corrosion rate of Al nanoparticles could be quantitatively suppressed by the coverage percentage of the polymer coating.

  20. Effect of the ionizing radiation in polyurethane of medical grade

    International Nuclear Information System (INIS)

    Ceron, P.; Rivera, T.; Calderon, J. A.; Paredes, L.

    2011-10-01

    The polyurethane is a material broadly used in implant medical devices, such as the connection blocks of the pacemakers and the insulator of the electrodes. Some patients that are users of these devices possibly have the necessity to receive external radiotherapy. For that reason is necessary to know the effects induced by the ionizing radiation in this polymer. In this study samples of Pellethane 2363 80a (thermoplastic polyurethane of medical grade) were irradiated. It was used the same energy and absorbed dose of a treatment of external radiotherapy in pelvis, by means of a linear accelerator of X-rays of 6 MeV and absorbed dose of 60 Gy to isocenter. The irradiation corresponding to the gamma sterilization of the material was reproduced (1, 5, 7.5, 10 and 25 kGy for the Co 60) the effects induced by the radiotherapy and for the sterilization in the material were studied by means of an analysis of the chemical connection, the molecular structure and identification of the functional groups of the polymer, by means of the infrared spectroscopy by Fourier transform in the infrared half region. (Author)

  1. Microphase separated structure and surface properties of fluorinated polyurethane resin

    International Nuclear Information System (INIS)

    Sudaryanto; Nishino, T.; Hori, Y.; Nakamae, K.

    2000-01-01

    The effect of fluorination on microphase separation and surface properties of segmented polyurethane (PU) resin were investigated. A series of fluorinated polyurethane resin (FPU) was synthesized by reacting a fluorinated diol with aromatic diisocyanate. The microphase separated structure of FPU was studied by thermal analysis, and small angle X-ray scattering (SAXS) as well as wide angle X-ray diffraction (WAXD). The surface structure and properties were characterized by X-ray photoelectron spectroscopy (XPS) and dynamic contact angle measurement. The incorporation of fluorine into hard segment brings the FPU to have a higher hard domain cohesion and increase the phase separation, however localization of fluorine on the surface could not be observed. On the other hands, localization of fluorine on the surface could be achieved for soft segment fluorinated PU without any significant change in microphase separated structure. The result from this study give an important basic information for designing PU coating material with a low surface energy and strong adhesion as well as for development of release film on pressure sensitive adhesive tape. (author)

  2. Comparison of polyurethane with cyanoacrylate in hemostasis of vascular injury in guinea pigs.

    Science.gov (United States)

    Kubrusly, Luiz Fernando; Formighieri, Marina Simões; Lago, José Vitor Martins; Graça, Yorgos Luiz Santos de Salles; Sobral, Ana Cristina Lira; Lago, Marianna Martins

    2015-01-01

    To evaluate the behavior of castor oil-derived polyurethane as a hemostatic agent and tissue response after abdominal aortic injury and to compare it with 2-octyl-cyanoacrylate. Twenty-four Guinea Pigs were randomly divided into three groups of eight animals (I, II, and III). The infrarenal abdominal aorta was dissected, clamped proximally and distally to the vascular puncture site. In group I (control), hemostasis was achieved with digital pressure; in group II (polyurethane) castor oil-derived polyurethane was applied, and in group III (cyanoacrylate), 2-octyl-cyanoacrylate was used. Group II was subdivided into IIA and IIB according to the time of preparation of the hemostatic agent. Mean blood loss in groups IIA, IIB and III was 0.002 grams (g), 0.008 g, and 0.170 g, with standard deviation of 0.005 g, 0.005 g, and 0.424 g, respectively (P=0.069). The drying time for cyanoacrylate averaged 81.5 seconds (s) (standard deviation: 51.5 seconds) and 126.1 s (standard deviation: 23.0 s) for polyurethane B (P=0.046). However, there was a trend (P=0.069) for cyanoacrylate to dry more slowly than polyurethane A (mean: 40.5 s; SD: 8.6 s). Furthermore, polyurethane A had a shorter drying time than polyurethane B (P=0.003), mean IIA of 40.5 s (standard deviation: 8.6 s). In group III, 100% of the animals had mild/severe fibrosis, while in group II only 12.5% showed this degree of fibrosis (P=0.001). Polyurethane derived from castor oil showed similar hemostatic behavior to octyl-2-cyanoacrylate. There was less perivascular tissue response with polyurethane when compared with cyanoacrylate.

  3. Guiding the orientation of smooth muscle cells on random and aligned polyurethane/collagen nanofibers.

    Science.gov (United States)

    Jia, Lin; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

    2014-09-01

    Fabricating scaffolds that can simulate the architecture and functionality of native extracellular matrix is a huge challenge in vascular tissue engineering. Various kinds of materials are engineered via nano-technological approaches to meet the current challenges in vascular tissue regeneration. During this study, nanofibers from pure polyurethane and hybrid polyurethane/collagen in two different morphologies (random and aligned) and in three different ratios of polyurethane:collagen (75:25; 50:50; 25:75) are fabricated by electrospinning. The fiber diameters of the nanofibrous scaffolds are in the range of 174-453 nm and 145-419 for random and aligned fibers, respectively, where they closely mimic the nanoscale dimensions of native extracellular matrix. The aligned polyurethane/collagen nanofibers expressed anisotropic wettability with mechanical properties which is suitable for regeneration of the artery. After 12 days of human aortic smooth muscle cells culture on different scaffolds, the proliferation of smooth muscle cells on hybrid polyurethane/collagen (3:1) nanofibers was 173% and 212% higher than on pure polyurethane scaffolds for random and aligned scaffolds, respectively. The results of cell morphology and protein staining showed that the aligned polyurethane/collagen (3:1) scaffold promote smooth muscle cells alignment through contact guidance, while the random polyurethane/collagen (3:1) also guided cell orientation most probably due to the inherent biochemical composition. Our studies demonstrate the potential of aligned and random polyurethane/collagen (3:1) as promising substrates for vascular tissue regeneration. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  4. Comparison of polyurethane with cyanoacrylate in hemostasis of vascular injury in guinea pigs

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Kubrusly

    2015-02-01

    Full Text Available Objective: To evaluate the behavior of castor oil-derived polyurethane as a hemostatic agent and tissue response after abdominal aortic injury and to compare it with 2-octyl-cyanoacrylate. Methods: Twenty-four Guinea Pigs were randomly divided into three groups of eight animals (I, II, and III. The infrarenal abdominal aorta was dissected, clamped proximally and distally to the vascular puncture site. In group I (control, hemostasis was achieved with digital pressure; in group II (polyurethane castor oil-derived polyurethane was applied, and in group III (cyanoacrylate, 2-octyl-cyanoacrylate was used. Group II was subdivided into IIA and IIB according to the time of preparation of the hemostatic agent. Results: Mean blood loss in groups IIA, IIB and III was 0.002 grams (g, 0.008 g, and 0.170 g, with standard deviation of 0.005 g, 0.005 g, and 0.424 g, respectively (P=0.069. The drying time for cyanoacrylate averaged 81.5 seconds (s (standard deviation: 51.5 seconds and 126.1 s (standard deviation: 23.0 s for polyurethane B (P=0.046. However, there was a trend (P=0.069 for cyanoacrylate to dry more slowly than polyurethane A (mean: 40.5 s; SD: 8.6 s. Furthermore, polyurethane A had a shorter drying time than polyurethane B (P=0.003, mean IIA of 40.5 s (standard deviation: 8.6 s. In group III, 100% of the animals had mild/severe fibrosis, while in group II only 12.5% showed this degree of fibrosis (P=0.001. Conclusion: Polyurethane derived from castor oil showed similar hemostatic behavior to octyl-2-cyanoacrylate. There was less perivascular tissue response with polyurethane when compared with cyanoacrylate.

  5. Synthesis, vibrational spectrometry and thermal characterizations of coordination polymers derived from divalent metal ions and hydroxyl terminated polyurethane as ligand

    Science.gov (United States)

    Laxmi; Khan, Shabnam; Kareem, Abdul; Zafar, Fahmina; Nishat, Nahid

    2018-01-01

    A series of novel coordination polyurethanes [HTPU-M, where M = Mn(II) 'd5', Ni(II) 'd8', and Zn(II) 'd10'] have been synthesized to investigate the effect of divalent metal ions coordination on structure, thermal and adsorption properties of low molecular weight hydroxyl terminated polyurethane (HTPU). HTPU-M have been synthesized in situ where, sbnd OH group of HTPU (synthesized by the condensation polymerization reaction of ethylene glycol (EG) and toluene diisocyanate (TDI) in presence of catalyst) on condensation polymerization with metal acetate in presence of acid catalyst synthesized HTPU-M followed by coordination of metal ions with hetero atoms. The structure, composition and geometry of HTPU-M have been confirmed by vibrational spectrometry (FTIR), 1H NMR, elemental analysis and UV-Visible spectroscopy. Morphological structures of HTPU-M were analyzed by X-Ray Diffraction analysis (XRD), Field Emission Scanning Electron Microscope (FE-SEM) with Energy Dispersive X-ray spectroscopy (EDX) and High Resolution Transmission Electron Microscope (HR-TEM) techniques. The thermal degradation pattern and thermal stability of HTPU-M in comparison to HTPU was investigated by thermal-gravimetric (TG)/differential thermal (DT), analyses along with Integral procedure decomposition temperature (IPDT) by Doyle method. The molecular weight of HTPU was determined by gel permeation chromatography (GPC). The preliminary adsorption/desorption studies of HTPU-M for Congo red (CR) was studied by batch adsorption techniques. The results indicated that HTPU-M have amorphous, layered morphology with higher number of nano-sized grooves in comparison to HTPU. Coordination of metal to HTPU plays a key role in enhancing the thermal stability [HTPU-Ni(II) > HTPU-Mn(II) > HTPU-Zn(II) > HTPU]. The HTPU-M can be utilized for industrial waste water treatment by removing environmental pollutants.

  6. Preparation, characterization and properties of acid functionalized multi-walled carbon nanotube reinforced thermoplastic polyurethane nanocomposites

    International Nuclear Information System (INIS)

    Kumar Barick, Aruna; Kumar Tripathy, Deba

    2011-01-01

    Graphical abstract: Highlights: → Preparation and characterization of TPU nanocomposite for tailor made applications. → The structural analyses were carried out by FTIR, WAXD, FESEM and HRTEM. → The thermal and dynamic mechanical properties were evaluated by TGA, DSC and DMA. → The dynamic rheological behavior was investigated by RPA in frequency sweep. → The frequency dependence of electrical properties was studied by LCR meter. - Abstract: The multi-walled carbon nanotube (MWNT) reinforced thermoplastic polyurethane (TPU) nanocomposites were prepared through melt compounding method followed by compression molding. The spectroscopic study indicated that a strong interfacial interaction was developed between carbon nanotube (CNT) and the TPU matrix in the nanocomposites. The microscopic observation showed that the CNTs were homogeneously dispersed throughout the TPU matrix well apart from a few clusters. The results from thermal analysis indicated that the glass transition temperature (T g ) and storage modulus (E') of the nanocomposites were increased with increase in CNTs content and their thermal stability were also improved in comparison with pure TPU matrix. The rheological analysis showed the low frequency plateau of shear modulus and the shear thinning behavior of the nanocomposites. The electrical behaviors of the nanocomposites are increased with increase in weight percent (wt%) of CNT loading. The mechanical properties of nanocomposites were substantially improved by the incorporation of CNTs into the TPU matrix.

  7. Thermal and dynamic mechanical characterization of thermoplastic polyurethane/organoclay nanocomposites prepared by melt compounding

    International Nuclear Information System (INIS)

    Barick, A.K.; Tripathy, D.K.

    2010-01-01

    Thermoplastic polyurethane (TPU) nanocomposites based on organically modified layered silicate (OMLS) were prepared by melt intercalation process followed by compression molding. Different percentage of organoclays was incorporated into the TPU matrix in order to examine the influence of the nanoscaled fillers on nanostructure morphology and material properties. The microscopic morphology of the nanocomposites was evaluated by wide angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The observation revealed that both nanoclay-polymer interactions and shear stress developed during melt mixing are responsible for the effectively organoclay dispersion in TPU matrix resulting intercalated/exfoliated morphology. Thermal stability of the nanocomposites measured by thermogravimetric analysis (TGA) was improved significantly with the addition of nanoclay. The differential scanning calorimetry (DSC) analysis reveals that melting point of the nanocomposites increased with incorporation of nanoclay. The dynamic mechanical properties of the TPU nanocomposites were analyzed using a dynamic mechanical thermal analyzer (DMTA), which indicates that the storage modulus (E'), loss modulus (E''), and glass transition temperature (T g ) are significantly increased with increasing nanoclay content.

  8. Novel Polyurethane Matrix Systems Reveal a Particular Sustained Release Behavior Studied by Imaging and Computational Modeling.

    Science.gov (United States)

    Campiñez, María Dolores; Caraballo, Isidoro; Puchkov, Maxim; Kuentz, Martin

    2017-07-01

    The aim of the present work was to better understand the drug-release mechanism from sustained release matrices prepared with two new polyurethanes, using a novel in silico formulation tool based on 3-dimensional cellular automata. For this purpose, two polymers and theophylline as model drug were used to prepare binary matrix tablets. Each formulation was simulated in silico, and its release behavior was compared to the experimental drug release profiles. Furthermore, the polymer distributions in the tablets were imaged by scanning electron microscopy (SEM) and the changes produced by the tortuosity were quantified and verified using experimental data. The obtained results showed that the polymers exhibited a surprisingly high ability for controlling drug release at low excipient concentrations (only 10% w/w of excipient controlled the release of drug during almost 8 h). The mesoscopic in silico model helped to reveal how the novel biopolymers were controlling drug release. The mechanism was found to be a special geometrical arrangement of the excipient particles, creating an almost continuous barrier surrounding the drug in a very effective way, comparable to lipid or waxy excipients but with the advantages of a much higher compactability, stability, and absence of excipient polymorphism.

  9. Synthesis and Thermomechanical Properties of Polyurethanes and Biocomposites Derived from Macauba Oil and Coconut Husk Fibers

    Directory of Open Access Journals (Sweden)

    Rafael L. Quirino

    2015-08-01

    Full Text Available This work reports on a very effective route to produce bio-based polyurethanes (PUs and composites with high content of renewable carbon sources. The PUs are prepared with polyols synthesized from macauba oil (Acrocomia aculeata and methylene diphenyl diisocyanate, at different [NCO]/[OH] molar ratios. Later, biocomposites are prepared with the as-obtained PUs reinforced with coconut husk fibers. The successful synthesis of natural oil-based polyols is ascribed to the hydroxylation and consumption of carbon-carbon double bonds in the fatty acid chains of the original starting oil as attested by FTIR spectroscopy. According to different thermal analysis techniques (TG, DTG, and DTA, the increase in the [NCO]/[OH] molar ratio improves the thermal stability of PUs, likely due to an increase of crosslinks. Dynamic mechanical analysis evidences the reinforcement effect of coconut husk fibers in bio-based PUs. The present PUs and composites are of low-cost and environmentally friendly materials for structural applications.

  10. Membrane Distillation of Meat Industry Effluent with Hydrophilic Polyurethane Coated Polytetrafluoroethylene Membranes.

    Science.gov (United States)

    Mostafa, M G; Zhu, Bo; Cran, Marlene; Dow, Noel; Milne, Nicholas; Desai, Dilip; Duke, Mikel

    2017-09-29

    Meat rendering operations produce stick water waste which is rich in proteins, fats, and minerals. Membrane distillation (MD) may further recover water and valuable solids, but hydrophobic membranes are contaminated by the fats. Here, commercial hydrophobic polytetrafluorethylene (PTFE) membranes with a hydrophilic polyurethane surface layer (PU-PTFE) are used for the first time for direct contact MD (DCMD) on real poultry, fish, and bovine stick waters. Metal membrane microfiltration (MMF) was also used to capture fats prior to MD. Although the standard hydrophobic PTFE membranes failed rapidly, PU-PTFE membranes effectively processed all stick water samples to colourless permeate with sodium rejections >99%. Initial clean solution fluxes 5-6 L/m²/h declined to less than half during short 40% water recovery tests for all stick water samples. Fish stick water uniquely showed reduced fouling and up to 78% water recovery. Lost flux was easily restored by rinsing the membrane with clean water. MMF prior to MD removed 92% of fats, facilitating superior MD performance. Differences in fouling between stick waters were attributed to temperature polarisation from higher melt temperature fats and relative proportions to proteins. Hydrophilic coated MD membranes are applicable to stick water processing but further studies should consider membrane cleaning and longer-term stability.

  11. Physicochemical characterization of chitosan/nylon6/polyurethane foam chemically cross-linked ternary blends.

    Science.gov (United States)

    Jayakumar, S; Sudha, P N

    2013-03-15

    Chitosan/nylon6/polyurethane foam (CS/Ny6/PUF) ternary blend was prepared and chemically cross-linked with glutaraldehyde. Structural, thermal and morphological studies were performed for the prepared ternary blends. Characterizations of the ternary blends were investigated by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM). The FTIR results showed that the strong intermolecular hydrogen bonds took place between CS, Ny6 and PUF. TGA and DSC studies reveal that the thermal stability of the blend is enhanced by glutaraldehyde as crosslinking agent. Results of XRD indicated that the relative crystalline of pure CS film was reduced when the polymeric network was reticulated by glutaraldehyde. Finally, the results of scanning electron microscopy (SEM) indicated that the morphology of the blend is rough and heterogeneous, further it confirms the interaction between the functional groups of the blend components. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Preparation and performance of porous phase change polyethylene glycol/polyurethane membrane

    International Nuclear Information System (INIS)

    Ke Guizhen; Xie Huifang; Ruan Ruping; Yu Weidong

    2010-01-01

    Based on the theory of clotty porous phase change materials, the porous membrane was prepared with the blend of polyurethane (PU) and two polyethylene glycol (PEG) systems. Studied by scanning electron microscope (SEM), Fourier transform infrared (FT-IR), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and thermo-gravimetric (TG) tests, the morphology structure, chemical composition, crystalline morphology, phase change behaviors and thermal stability of porous phase change membrane were investigated. The results showed that the PU/PEG membrane had obvious porous structural feature, suitable transition temperature and high transition enthalpy. It is a flexible membrane with good energy storage function. When it is between solid and liquid transfer state in microcosms, the membrane can still keep solid shape in macroscopic state at high temperature during phase transition processing. It means that porous membrane PCM can be regarded as functional polymer. This method solved the problem of low working materials content in phase change textile. It succeeded in introducing the porous technology into functional textile's formation, and developed a new way to improve the phase change enthalpy largely for adjustable textile.

  13. Biogas production from UASB and polyurethane carrier reactors treating sisal processing wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Rubindamayugi, M S.T.; Salakana, L K.P. [Univ. of Dar es Salaam, Faculty of Science, Applied Microbiology Unit (Tanzania, United Republic of)

    1998-12-31

    The fundamental benefits which makes anaerobic digestion technology (ADT) attractive to the poor developing include the low cost and energy production potential of the technology. In this study the potential of using UASB reactor and Polyurethane Carrier Reactor (PCR) as pollution control and energy recovery systems from sisal wastewater were investigated in lab-scale reactors. The PCR demonstrated the shortest startup period, whereas the UASB reactor showed the highest COD removal efficiency 79%, biogas production rate (4.5 l biogas/l/day) and process stability than the PCR under similar HRT of 15 hours and OLR of 8.2 g COD/l/day. Both reactor systems became overloaded at HRT of 6 hours and OLR of 15.7 g COD/l/day, biogas production ceased and reactors acidified to pH levels which are inhibiting to methanogenesis. Based on the combined results on reactor performances, the UASB reactor is recommended as the best reactor for high biogas production and treatment efficiency. It was estimated that a large-scale UASB reactor can be designed under the same loading conditions to produce 2.8 m{sup 3} biogas form 1 m{sup 3} of wastewater of 5.16 kg COD/m{sup 3}. Wastewater from one decortication shift can produce 9,446 m{sup 3} og biogas. The energy equivalent of such fuel energy is indicated. (au)

  14. Biogas production from UASB and polyurethane carrier reactors treating sisal processing wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Rubindamayugi, M.S.T.; Salakana, L.K.P. [Univ. of Dar es Salaam, Faculty of Science, Applied Microbiology Unit (Tanzania, United Republic of)

    1997-12-31

    The fundamental benefits which makes anaerobic digestion technology (ADT) attractive to the poor developing include the low cost and energy production potential of the technology. In this study the potential of using UASB reactor and Polyurethane Carrier Reactor (PCR) as pollution control and energy recovery systems from sisal wastewater were investigated in lab-scale reactors. The PCR demonstrated the shortest startup period, whereas the UASB reactor showed the highest COD removal efficiency 79%, biogas production rate (4.5 l biogas/l/day) and process stability than the PCR under similar HRT of 15 hours and OLR of 8.2 g COD/l/day. Both reactor systems became overloaded at HRT of 6 hours and OLR of 15.7 g COD/l/day, biogas production ceased and reactors acidified to pH levels which are inhibiting to methanogenesis. Based on the combined results on reactor performances, the UASB reactor is recommended as the best reactor for high biogas production and treatment efficiency. It was estimated that a large-scale UASB reactor can be designed under the same loading conditions to produce 2.8 m{sup 3} biogas form 1 m{sup 3} of wastewater of 5.16 kg COD/m{sup 3}. Wastewater from one decortication shift can produce 9,446 m{sup 3} og biogas. The energy equivalent of such fuel energy is indicated. (au)

  15. UV-Surface Treatment of Fungal Resistant Polyether Polyurethane Film-Induced Growth of Entomopathogenic Fungi.

    Science.gov (United States)

    Lando, Gabriela Albara; Marconatto, Letícia; Kessler, Felipe; Lopes, William; Schrank, Augusto; Vainstein, Marilene Henning; Weibel, Daniel Eduardo

    2017-07-18

    Synthetic polymers are the cause of some major environmental impacts due to their low degradation rates. Polyurethanes (PU) are widely used synthetic polymers, and their growing use in industry has produced an increase in plastic waste. A commercial polyether-based thermoplastic PU with hydrolytic stability and fungus resistance was only attacked by an entomopathogenic fungus, Metarhiziumanisopliae , when the films were pre-treated with Ultraviolet (UV) irradiation in the presence of reactive atmospheres. Water contact angle, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR), scanning electron microscopy (SEM), and profilometer measurements were mainly used for analysis. Permanent hydrophilic PU films were produced by the UV-assisted treatments. Pristine polyether PU films incubated for 10, 30, and 60 days did not show any indication of fungal growth. On the contrary, when using oxygen in the UV pre-treatment a layer of fungi spores covered the sample, indicating a great adherence of the microorganisms to the polymer. However, if acrylic acid vapors were used during the UV pre-treatment, a visible attack by the entomopathogenic fungi was observed. SEM and FTIR-ATR data showed clear evidence of fungal development: growth and ramifications of hyphae on the polymer surface with the increase in UV pre-treatment time and fungus incubation time. The results indicated that the simple UV surface activation process has proven to be a promising alternative for polyether PU waste management.

  16. Membrane Distillation of Meat Industry Effluent with Hydrophilic Polyurethane Coated Polytetrafluoroethylene Membranes

    Directory of Open Access Journals (Sweden)

    M. G. Mostafa

    2017-09-01

    Full Text Available Meat rendering operations produce stick water waste which is rich in proteins, fats, and minerals. Membrane distillation (MD may further recover water and valuable solids, but hydrophobic membranes are contaminated by the fats. Here, commercial hydrophobic polytetrafluorethylene (PTFE membranes with a hydrophilic polyurethane surface layer (PU-PTFE are used for the first time for direct contact MD (DCMD on real poultry, fish, and bovine stick waters. Metal membrane microfiltration (MMF was also used to capture fats prior to MD. Although the standard hydrophobic PTFE membranes failed rapidly, PU-PTFE membranes effectively processed all stick water samples to colourless permeate with sodium rejections >99%. Initial clean solution fluxes 5–6 L/m2/h declined to less than half during short 40% water recovery tests for all stick water samples. Fish stick water uniquely showed reduced fouling and up to 78% water recovery. Lost flux was easily restored by rinsing the membrane with clean water. MMF prior to MD removed 92% of fats, facilitating superior MD performance. Differences in fouling between stick waters were attributed to temperature polarisation from higher melt temperature fats and relative proportions to proteins. Hydrophilic coated MD membranes are applicable to stick water processing but further studies should consider membrane cleaning and longer-term stability.

  17. Selective paint coatings for coloured solar absorbers: Polyurethane thickness insensitive spectrally selective (TISS) paints (Part II)

    Energy Technology Data Exchange (ETDEWEB)

    Orel, B.; Spreizer, H.; Surca Vuk, A.; Fir, M. [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Merlini, D.; Vodlan, M. [Color d.d., Cesta komandanta Staneta 4, SI-1230 Medvode (Slovenia); Koehl, M. [Fraunhofer-Institute for Solar Energy Systems ISE, Heidenhofstr. 2, D-79110 Freiburg (Germany)

    2007-01-23

    Red, green and blue paints were prepared for use as thickness insensitive spectrally selective (TISS) paint coatings for solar facade absorbers. The paints were composed of a polyurethane resin binder in which various pigments were incorporated in such a way that they formed stable paint dispersions, satisfying stability criteria for facade coatings. A low emittance of the paints was achieved by using low-emittance aluminium flake pigments combined with iron oxide (red coloured paints). Black pigment was added to adjust solar absorptance. Blue and green paints were made by the addition of coloured aluminium flake pigment and the solar absorptance was also adjusted by the addition of black pigment. Efficiency for photo-thermal conversion of solar radiation was assessed by evaluation of the corresponding performance criteria, which enabled the selection of paints whose performance criteria values were higher than 0 (spectrally non-selective black coating). The results confirmed that blue and green paints and to minor extent red ones, combined selectivity with colour. The morphology of the paints was assessed, revealing that the colours originated from the deposition of finely dispersed colour and/or black pigment on the surface of the aluminium flakes during paint preparation. (author)

  18. Plasma immersion ion implantation of polyurethane shape memory polymer: Surface properties and protein immobilization

    Science.gov (United States)

    Cheng, Xinying; Kondyurin, Alexey; Bao, Shisan; Bilek, Marcela M. M.; Ye, Lin

    2017-09-01

    Polyurethane-type shape memory polymers (SMPU) are promising biomedical implant materials due to their ability to recover to a predetermined shape from a temporary shape induced by thermal activation close to human body temperature and their advantageous mechanical properties including large recovery strains and low recovery stresses. Plasma Immersion Ion Implantation (PIII) is a surface modification process using energetic ions that generates radicals in polymer surfaces leading to carbonisation and oxidation and the ability to covalently immobilise proteins without the need for wet chemistry. Here we show that PIII treatment of SMPU significantly enhances its bioactivity making SMPU suitable for applications in permanent implantable biomedical devices. Scanning Electron Microscopy (SEM), contact angle measurements, surface energy measurements, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterise the PIII modified surface, including its after treatment aging kinetics and its capability to covalently immobilise protein directly from solution. The results show a substantial improvement in wettability and dramatic changes of surface chemical composition dependent on treatment duration, due to the generation of radicals and subsequent oxidation. The SMPU surface, PIII treated for 200s, achieved a saturated level of covalently immobilized protein indicating that a full monolayer coverage was achieved. We conclude that PIII is a promising and efficient surface modification method to enhance the biocompatibility of SMPU for use in medical applications that demand bioactivity for tissue integration and stability in vivo.

  19. UV-Surface Treatment of Fungal Resistant Polyether Polyurethane Film-Induced Growth of Entomopathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Gabriela Albara Lando

    2017-07-01

    Full Text Available Synthetic polymers are the cause of some major environmental impacts due to their low degradation rates. Polyurethanes (PU are widely used synthetic polymers, and their growing use in industry has produced an increase in plastic waste. A commercial polyether-based thermoplastic PU with hydrolytic stability and fungus resistance was only attacked by an entomopathogenic fungus, Metarhiziumanisopliae, when the films were pre-treated with Ultraviolet (UV irradiation in the presence of reactive atmospheres. Water contact angle, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR, scanning electron microscopy (SEM, and profilometer measurements were mainly used for analysis. Permanent hydrophilic PU films were produced by the UV-assisted treatments. Pristine polyether PU films incubated for 10, 30, and 60 days did not show any indication of fungal growth. On the contrary, when using oxygen in the UV pre-treatment a layer of fungi spores covered the sample, indicating a great adherence of the microorganisms to the polymer. However, if acrylic acid vapors were used during the UV pre-treatment, a visible attack by the entomopathogenic fungi was observed. SEM and FTIR-ATR data showed clear evidence of fungal development: growth and ramifications of hyphae on the polymer surface with the increase in UV pre-treatment time and fungus incubation time. The results indicated that the simple UV surface activation process has proven to be a promising alternative for polyether PU waste management.

  20. Influences of the Ratio of Polyol and MDI on the Acoustic Parameters of Polyurethane

    Science.gov (United States)

    Wang, Yonghua; Liu, Zheming; Wu, Haiquan; Zhang, Chengchun; Yu, Huadong; Ren, Luquan; Ichchou, Mohamed

    2018-05-01

    In this paper, the influence of different ratio of polyol and MDI on the absorption coefficient and acoustic parameters of polyurethane was studied. Ratio of 100:40 and 100:45 show the best sound absorption performance, and the change trend of transmission loss and sound absorption coefficient are opposite. The flow resistance increased with the increasing of the ratio of polyol and MDI, the greater the flow resistance, the worse the high frequency sound absorption property of the polyurethane. When the ratio of polyol and MDI keep 100:45, the minimum porosity of sample, the polyurethane porosity increase with the ratio of polyol and MDI increase.

  1. Electron beam curable branched chain polyurethane acrylates for magnetic media coatings

    International Nuclear Information System (INIS)

    Ukachi, Takashi; Haga, Kei-ichi; Matsumura, Yoshio

    1989-01-01

    Electron beam curable binder resins have been studied to realize the high quality magnetic coatings. It was supposed that resins with a higher crosslink density could lead to magnetic coatings with higher abrasion resistance. Branched chain polyurethane acrylates show a higher degree of cure by irradiation with an electron beam in comparison with linear polyurethane acrylates. This paper describes the potential wear resistance between properties of magnetic coatings and the physical properties of the cured unpigmented branched chain polyurethane acrylates that were used as the binder resins. (author)

  2. Comparison between properties of polyurethane nano composites prepared by two different methods

    International Nuclear Information System (INIS)

    Barmar, M.; Barikani, M.; Fereidoonnia, M.

    2009-01-01

    In this work, a thermoplastic polyurethane elastomer model based on polytetramethylene glycol. toluene diisocyanate and 1,4-butanediol was selected and synthesized. According to this model two types of polyurethane nano composites were prepared by in situ polymerization and melt intercalation procedures. The organo-modified nano clay was used in nano composites samples in 0.4 weight percent level. The prepared nano composites were studied by WAXD, tensile and thermal analysis. Thermal properties of the nano composites were higher than those of pure polyurethane elastomers. Nano composites prepared via melt intercalation method showed a lower tensile strength and hardness than those prepared through in situ polymerization method

  3. Radiation degradation of polyether-polyurethane induced by E-beams

    International Nuclear Information System (INIS)

    Huang Wei; Xu Yunshu; Chen Xiaojun; Gao Xiaoling; Xiong Jie; Fu Yibei

    2006-01-01

    Polyether-urethane samples were irradiated at the dose range from 10kGy to 2000 kGy by 2 MeV electron beams. Volatile species from the polymer degradation were analyzed quantitatively and qualitatively with GC/MS. Thermal properties and micro-phase separation of the samples were examined by TG and the morphology was studied by TEM and SEM. The irradiated polyether-polyurethane evolves mainly CO 2 along with H 2 , CH 4 and C 2 H 6 etc. The quantity of CO 2 increased with the dose during irradiations of up to 1500 kGy. And the H 2 yield had a trend of increase, while the CH 4 yield rose to a maximum before it decreased to a stable level. Because the soft and hard segments on ETPU chains are thermally compatible, phase separation takes place in its inner part. DTG analysis of the irradiated samples showed that the samples went to phase separations at a thermal decomposition peak of 325-335 degree C, which stands for the phase separation of the hard segment, and at 470-485 degree C for the soft segment. The lower temperature peak was stronger than the high temperature peak, and this indicated different thermal stabilities of the soft and hard segments. TEM images of the samples indicated that excellent compatibility of the hard and soft segments in pristine and the samples irradiated to low doses. It could be clearly seen from the TEM images that there were two phases in the sample irradiated to over 800 kGy. The electrons broke the hydrogen bond of >NH and >C=O on the hard segment and -O- on the soft part. Due to the disappearance of hydrogen bond, compatibility degree of the soft and hard segments reduced, phase range of the soft segment increased, hence the obvious phase separation. SEM images of the irradiated samples illustrated that spherical pores of polyurethane collapsed to form cracks at low doses, and they were damaged seriously at high doses. SEM images of the samples irradiated under constant stress indicated that elasticity of the sample was seriously

  4. A finite element/level set model of polyurethane foam expansion and polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine Cardinal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunini, Victor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Noble, David R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tinsley, James [Honeywell Federal Manufacturing & Technologies, Kansas City, MO (United States); Mondy, Lisa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    Polyurethane foams are used widely for encapsulation and structural purposes because they are inexpensive, straightforward to process, amenable to a wide range of density variations (1 lb/ft3 - 50 lb/ft3), and able to fill complex molds quickly and effectively. Computational model of the filling and curing process are needed to reduce defects such as voids, out-of-specification density, density gradients, foam decomposition from high temperatures due to exotherms, and incomplete filling. This paper details the development of a computational fluid dynamics model of a moderate density PMDI structural foam, PMDI-10. PMDI is an isocyanate-based polyurethane foam, which is chemically blown with water. The polyol reacts with isocyanate to produces the polymer. PMDI- 10 is catalyzed giving it a short pot life: it foams and polymerizes to a solid within 5 minutes during normal processing. To achieve a higher density, the foam is over-packed to twice or more of its free rise density of 10 lb/ft3. The goal for modeling is to represent the expansion, filling of molds, and the polymerization of the foam. This will be used to reduce defects, optimize the mold design, troubleshoot the processed, and predict the final foam properties. A homogenized continuum model foaming and curing was developed based on reaction kinetics, documented in a recent paper; it uses a simplified mathematical formalism that decouples these two reactions. The chemo-rheology of PMDI is measured experimentally and fit to a generalized- Newtonian viscosity model that is dependent on the extent of cure, gas fraction, and temperature. The conservation equations, including the equations of motion, an energy balance, and three rate equations are solved via a stabilized finite element method. The equations are combined with a level set method to determine the location of the foam-gas interface as it evolves to fill the mold. Understanding the thermal history and loads on the foam due to exothermicity and oven

  5. Influence of therapeutic radiation on polycaprolactone and polyurethane biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, Shelley L. [Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Whittington, Abby R., E-mail: awhit@mse.vt.edu [Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

    2016-03-01

    ABSTRACT: Biomedical polymers are exposed in vivo to ionizing radiation as implants, coatings and bystander materials. High levels of ionizing radiation (e.g. X-ray and gamma) have been reported to cause degradation and/or cross-linking in many polymers. This pilot study sought to determine causes of failure, by investigating how therapeutic radiation affects two different porous polymeric scaffolds: polycaprolactone (PCL) and polyurethane (PU). PCL is a bioresorbable material used in biomedical devices (e.g., dentistry, internal fixation devices and targeted drug delivery capsules). PU is commonly used in medical applications (e.g., coatings for pacemakers, tissue expanders, catheter tubing and wound dressings). PU was specifically fabricated to be a non-degradable polymer in this study. Porous scaffolds, fabricated using solvent casting and/or salt leeching techniques, were placed in phosphate buffered saline (PBS, pH = 7.4) and exposed to typical cancer radiotherapy. A total dose of 50 Gy was broken into 25 doses over an eleven-week period. Collected PBS was tested for polymer leachants and degradation products using Gas Chromatography Mass Spectroscopy (GC–MS), results revealed no analyzable leachants from either polymer. Scaffolds were characterized using Environmental Scanning Electron Microscopy, Size-exclusion chromatography (SEC), Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). No gross visual changes were observed in either polymer, however PU exhibited microstructure changes after irradiation. Increased number average molecular weight and weight average molecular weight in PCL and PU were observed after irradiation, indicating crosslinking. PU displayed an increase in intrinsic viscosity that further confirms increased crosslinking. PCL and PU showed decreases in crystallinity after irradiation, and PU crystallinity shifted from long-range-order hard segments to short-range-order hard segments after

  6. Influence of therapeutic radiation on polycaprolactone and polyurethane biomaterials

    International Nuclear Information System (INIS)

    Cooke, Shelley L.; Whittington, Abby R.

    2016-01-01

    ABSTRACT: Biomedical polymers are exposed in vivo to ionizing radiation as implants, coatings and bystander materials. High levels of ionizing radiation (e.g. X-ray and gamma) have been reported to cause degradation and/or cross-linking in many polymers. This pilot study sought to determine causes of failure, by investigating how therapeutic radiation affects two different porous polymeric scaffolds: polycaprolactone (PCL) and polyurethane (PU). PCL is a bioresorbable material used in biomedical devices (e.g., dentistry, internal fixation devices and targeted drug delivery capsules). PU is commonly used in medical applications (e.g., coatings for pacemakers, tissue expanders, catheter tubing and wound dressings). PU was specifically fabricated to be a non-degradable polymer in this study. Porous scaffolds, fabricated using solvent casting and/or salt leeching techniques, were placed in phosphate buffered saline (PBS, pH = 7.4) and exposed to typical cancer radiotherapy. A total dose of 50 Gy was broken into 25 doses over an eleven-week period. Collected PBS was tested for polymer leachants and degradation products using Gas Chromatography Mass Spectroscopy (GC–MS), results revealed no analyzable leachants from either polymer. Scaffolds were characterized using Environmental Scanning Electron Microscopy, Size-exclusion chromatography (SEC), Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). No gross visual changes were observed in either polymer, however PU exhibited microstructure changes after irradiation. Increased number average molecular weight and weight average molecular weight in PCL and PU were observed after irradiation, indicating crosslinking. PU displayed an increase in intrinsic viscosity that further confirms increased crosslinking. PCL and PU showed decreases in crystallinity after irradiation, and PU crystallinity shifted from long-range-order hard segments to short-range-order hard segments after

  7. Copper uptake kinetics and regulation in a marine fish after waterborne copper acclimation

    Energy Technology Data Exchange (ETDEWEB)

    Dang Fei; Zhong Huan [AMCE and Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong); Wang Wenxiong, E-mail: wwang@ust.hk [AMCE and Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong)

    2009-09-14

    The uptake kinetics and regulation of copper in a marine predatory fish, the black sea bream Acanthopagrus schlegeli after acclimation to waterborne Cu were examined, using radiotracer techniques. The dissolved Cu uptake followed a linear pattern during the time of exposure, and the calculated uptake rate constant was 6.24 L kg{sup -1} day{sup -1}. The efflux rate constant was 0.091 day{sup -1} following dietary uptake of Cu, and the dietary assimilation efficiency (AE) of Cu varied between 1.7% and 10.9% after the fish were fed with three types of prey (oysters, clams and brine shrimp). After the fish were acclimated at a nominal concentration of 50 {mu}g Cu L{sup -1} for 14 days, the Cu uptake rate and efflux rate constant did not change significantly, but the Cu body concentrations and metallothionein (MT) concentrations in fish tissues increased significantly. Subcellular Cu distributions were also modified. Significant MT induction was observed in response to increased Cu tissue concentrations, indicating that MT rather than the uptake kinetics may play a primary role in Cu regulation during waterborne Cu acclimation in this marine fish. Moreover, the high Cu efflux may also be important in Cu regulation during long-term exposure. Our modeling calculations indicated that dietary uptake was likely to be the main route for Cu bioaccumulation in the fish, and the relative contribution of waterborne and dietary uptake depended on the bioconcentration factor (BCF) of the prey and ingestion rate of fish.

  8. Are soil and waterborne parasitic infections health risk for worker populations in southeast Turkey?

    Directory of Open Access Journals (Sweden)

    Sibel Ak

    2017-06-01

    Full Text Available Objective: The soil and waterborne parasitic infections rate is high degree in developed and developing countries. Migratory workers have greater exposure to these parasitic infections and a lot of morbidity due to these infections in workers. For this reason, we aimed to investigate the presence of soil and waterborne parasites in the Gaziantep Organized Industrial Zone of southeast Turkey. Methods: A total of 25 environmental samples (18 soil samples and 7 water samples were taken from The Gaziantep Organized Industrial Zone, in two different seasons (summer and winter. All of the samples were screened for parasites using microscopic examination and culture methods. The parasites were genotyped with polymerase chain reaction and DNA sequencing analysis. Results: The prevalence of soil and water transmitted parasites was found to be positive 52% (13/25 in summer while there is no any parasites in winter. It was found 22.3% (4/18 Acanthamoeba (genotype4, 16.6% (3/18 Ascaris lumbricoides, 11.1% (2/18 Strongoides stercoralis in soil samples and 14.3% (1/7 Acanthamoeba (genotype 4, 42.9% (3/7 Blastocystis (subtype3 in all of water samples. Conclusion: The migratory worker waves have always shaped the ethnic composition and public health problem of the province of Gaziantep. Climate change has the potential to influence prevalence of parasite and our study has shown that increased prevalence of parasite in summer. The global target for the coming years should be to remove the deaths from earth and waterborne parasitic infections in the worker populations. Thus, we prevent the distribution of parasitic infections in our country.

  9. Relationship between free volume and mechanical properties of polyurethane irradiated by gamma rays

    International Nuclear Information System (INIS)

    Heliang Sui; Xin Ju; Xueyong Liu; Fachun Zhong; Xiaoyan Li; Baoyi Wang

    2014-01-01

    Polyurethane was irradiated at various gamma radiation doses up to 1,000 kGy at room temperature in nitrogen. Positron annihilation lifetime spectroscopy, tensile test and dynamic mechanical analysis were used to find the relationship between free volume and mechanical properties. An increase of the free volume fraction in soft segments (SS) and a decrease of the free volume fraction in hard segments (HS) during gamma radiation was observed and analyzed. The results showed that HS in polyurethane had the excellent resistance to gamma radiation, whereas SS had a tendency to degrade. The reason for the decrease of the strain at break and the ultimate tensile strength was analyzed, which showed the changes in the mechanical properties of polyurethane irradiated by gamma rays were mainly determined by the changes of free volume in SS. If the resistance properties of polyurethanes exposed to radiations need to be improved, SS should be paid more attention to. (author)

  10. Development of test systems for characterizing emissions from spray polyurethane foam insulation (SPFI)

    Science.gov (United States)

    The relationship between onsite manufacture of spray polyurethane foam insulation (SPFI) and potential exposures to diisocyanates, amines, flame retardants (FRs), blowing agents, aldehydes and other organic compounds that may be emitted from SPFI is not well understood. EPA is de...

  11. Thermal behaviour and corrosion resistance of nano-ZnO/polyurethane film

    Science.gov (United States)

    Virgawati, E.; Soegijono, B.

    2018-03-01

    Hybrid materials Nano-ZnO/polyurethane film was prepared with different zinc oxide (ZnO) content in polyurethane as a matrix. The film was deposited on low carbon steel plate using high volume low pressure (HVLP) method. To observe thermal behaviour of the film, the sample was investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Fourier transform infrared spectroscopy (FTIR) was used to see whether any chemical reaction of ZnO in polyurethane occured. TGA and FTIR results showed that the decomposition temperature shifted to a higher point and the chemical reaction of zinc oxide in polyurethane occurred. The surface morphology changed and the corrosion resistance increased with an increase of ZnO content

  12. The Development of Testing Methods for Characterizing Emissions and Sources of Exposures from Polyurethane Products

    Science.gov (United States)

    The relationship between onsite manufacture of spray polyurethane foam insulation (SPFI) and potential exposures is not well understood. Currently, no comprehensive standard test methods exist for characterizing and quantifying product emissions. Exposures to diisocyanate compoun...

  13. Improving sensitivity of the polyurethane/CNT laminate strain sensor by controlled mechanical preload

    International Nuclear Information System (INIS)

    Slobodian, Petr; Olejnik, Robert; Matyas, Jiri; Babar, Dipak Gorakh

    2016-01-01

    This article describes strain detection potential of polyurethane/CNT layered composite and further possible enhance of its sensitivity to strain, expressed by value of gauge factor, GF, employing its controlled mechanical preload. In course of its fabrication a non-woven polyurethane membrane made by electro spinning was used as filtering membrane for CNT aqueous dispersion. Final CNT polyurethane laminate composite is prepared by compression molding. Produced polyurethane/CNT composite laminate is electrically conductive and high elastic. Its elongation leads to change of its macroscopic electrical resistance. Changes in resistance are further reversible, reproducible and can monitor deformation in real time. Gauge factor reaches very high values around 8 for strain reaching 3.5% comparing with conventional metallic strain gauges. Finally, controlled mechanical preload significantly increases value of GF. For example for value of 8.1% of preload value of GF reaches 23.3 for strain 3.5%. (paper)

  14. Acyclic N-halamine-immobilized polyurethane: Preparation and antimicrobial and biofilm-controlling functions

    Science.gov (United States)

    Luo, Jie; Porteous, Nuala; Lin, Jiajin; Sun, Yuyu

    2015-01-01

    Hydroxyl groups were introduced onto polyurethane surfaces through 1,6-hexamethylene diisocyanate activation, followed by diethanolamine hydroxylation. Polymethacrylamide was covalently attached to the hydroxylated polyurethane through surface grafting polymerization of methacrylamide using cerium (IV) ammonium nitrate as an initiator. After bleach treatment, the amide groups of the covalently bound polymethacrylamide chains were transformed into N-halamines. The new N-halamine-immobilized polyurethane provided a total sacrifice of 107–108 colony forming units per milliliter of Staphylococcus aureus (Gram-positive bacteria), Escherichia coli (Gram-negative bacteria), and Candida albicans (fungi) within 10 min and successfully prevented bacterial and fungal biofilm formation. The antimicrobial and biofilm-controlling effects were both durable and rechargeable, pointing to great potentials of the new acyclic N-halamine-immobilized polyurethane for a broad range of related applications. PMID:26089593

  15. Oleic and Undecylenic Acids as Renewable Feedstocks in the Synthesis of Polyols and Polyurethanes

    Directory of Open Access Journals (Sweden)

    Virginia Cádiz

    2010-10-01

    Full Text Available Nowadays, the utilization of raw materials derived from renewable feedstock is in the spotlight of the chemical industry, as vegetable oils are one of the most important platform chemicals due to their universal availability, inherent biodegradability and low price. Taking into account that polyurethanes are one of the most important industrial products exhibiting versatile properties suitable for use in many fields, our research is focused on exploiting fatty acids in the preparation of biobased polyols and polyurethanes. This review is organized as a function of the nature of the final polyurethane systems; hence we describe the preparation of linear thermoplastic and crosslinked polyurethanes derived from oleic and undecylenic acids-based diols and polyols, respectively.

  16. Synthesis and characterization of conductive, biodegradable, elastomeric polyurethanes for biomedical applications.

    Science.gov (United States)

    Xu, Cancan; Yepez, Gerardo; Wei, Zi; Liu, Fuqiang; Bugarin, Alejandro; Hong, Yi

    2016-09-01

    Biodegradable conductive polymers are currently of significant interest in tissue repair and regeneration, drug delivery, and bioelectronics. However, biodegradable materials exhibiting both conductive and elastic properties have rarely been reported to date. To that end, an electrically conductive polyurethane (CPU) was synthesized from polycaprolactone diol, hexadiisocyanate, and aniline trimer and subsequently doped with (1S)-(+)-10-camphorsulfonic acid (CSA). All CPU films showed good elasticity within a 30% strain range. The electrical conductivity of the CPU films, as enhanced with increasing amounts of CSA, ranged from 2.7 ± 0.9 × 10(-10) to 4.4 ± 0.6 × 10(-7) S/cm in a dry state and 4.2 ± 0.5 × 10(-8) to 7.3 ± 1.5 × 10(-5) S/cm in a wet state. The redox peaks of a CPU1.5 film (molar ratio CSA:aniline trimer = 1.5:1) in the cyclic voltammogram confirmed the desired good electroactivity. The doped CPU film exhibited good electrical stability (87% of initial conductivity after 150 hours charge) as measured in a cell culture medium. The degradation rates of CPU films increased with increasing CSA content in both phosphate-buffered solution (PBS) and lipase/PBS solutions. After 7 days of enzymatic degradation, the conductivity of all CSA-doped CPU films had decreased to that of the undoped CPU film. Mouse 3T3 fibroblasts proliferated and spread on all CPU films. This developed biodegradable CPU with good elasticity, electrical stability, and biocompatibility may find potential applications in tissue engineering, smart drug release, and electronics. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2305-2314, 2016. © 2016 Wiley Periodicals, Inc.

  17. Preparation and properties of new cross-linked polyurethane acrylate electrolytes for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, P.; Vasudevan, T.; Gopalan, A. [Department of Industrial Chemistry, Alagappa University, Karaikudi-630 003 (India); Lee, Kwang-Pill [Department of Chemistry Education, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

    2006-09-29

    A cross-linked polyurethane acrylate (PUA) is synthesized by end-capping a hexamethylene diisocyanate, hexamethylene diisocyanate/poly(ethylene glycol)-based prepolymer with hydroxy butyl methacrylate (HBMA). Significant interactions of lithium ions with the soft and hard segments of the host polymer are observed for the PUA complexed with lithium perchlorate (LiClO{sub 4}) by means of differential scanning calorimetry (DSC), and Fourier transform infra-red (FT-IR) spectroscopy measurements. The DSC results indicate the formation of transient cross-links with the ether oxygen of the soft segment and mixing of soft and hard phases induced by the Li{sup +} ions. The results of FT-IR spectroscopy and thermogravimetric analysis measurements support the formation of different types of complexes by interaction of Li{sup +} ions with different coordination sites of PUA. No detectable interactions are found between Li{sup +} ions and groups in HBMA. In addition, PUA follows the Arrhenius relationship for ion transport. Predominant formation of contact ion-pairs of LiClO{sub 4} is observed through a.c. conductivity and DSC measurements. The lithium stripping-plating process is reversible and this implies better electrochemical stability over the working voltage range. Also, the PUA electrolyte shows better compatibility with lithium metal as inferred from impedance measurements and has a good cationic transference number that is suitable for the material to be used as a solid polymer electrolyte. Addition of HBMA into the PU matrix improves the tensile strength of the cross-linked PUA. Swelling measurements of PUA with plasticizer indicate better dimensional stability. A cell is constructed with PUA as the electrolyte and its performance is evaluated. (author)

  18. Hard and transparent hybrid polyurethane coatings using in situ incorporation of calcium carbonate nanoparticles

    International Nuclear Information System (INIS)

    Yao Lu; Yang Jie; Sun Jing; Cai Lifang; He Linghao; Huang Hui; Song Rui; Hao Yongmei

    2011-01-01

    Highlights: → In situ mineralization via gas diffusion was adopted for a good dispersion of calcium carbonate nanoparticles in the polymeric PU matrix. → Hybrid films with high dispersion, transparency, robust and thermal stability can be obtained by controlling the CaCO 3 loading. → The hybrid films display a significant improvement in its water resistance, surface hardness, scratch resistance and flexibility, with the introduction of CaCO 3 , and all coatings exhibited excellent chemical resistance and adhesion. - Abstract: The combination of hardness, scratch resistance, and flexibility is a highly desired feature in many coating applications. The aim of this study is to achieve this goal through the in situ introduction of an unmodified calcium carbonate (CaCO 3 ) into a water-soluble polyurethane (PU) matrix. Smooth and (semi-) transparent films were prepared from both the neat PU and the CaCO 3 -filled composites. As evidenced by the measurements from scanning electron microscopy (SEM), optical microscopy, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), hybrid films with high dispersion, transparency, robustness and thermal stability could be obtained by controlling the CaCO 3 loading. The storage modulus could increase from 441 MPa of neat PU matrix to 1034 MPa of hybrid film containing 2% (w/w) CaCO 3 . In addition, the same hybrid films displayed a significant improvement in its water resistance. In this case, the water-uptake ratio decreased from 41.54% of PU to 2.21% of hybrid film containing 2% (w/w) CaCO 3 . Moreover, with the introduction of CaCO 3 , conventional coating characterization methods demonstrated an increase in the surface hardness, scratch resistance and flexibility, and all coatings exhibited excellent chemical resistance and adhesion.

  19. Tissue-specific Bio-accumulation of Metals in Fish during Chronic Waterborne and Dietary Exposures

    Directory of Open Access Journals (Sweden)

    M. Javed

    2012-10-01

    Full Text Available Juvenile (120-day three fish species viz. Catla catla, Labeo rohita and Cirrhina mrigala were exposed to chronic sub-lethal concentrations (1/3rd of LC50/LD50 of waterborne and dietary copper (Cu, cadmium (Cd, zinc (Zn, nickel (Ni and cobalt (Co, separately, in glass aquaria under constant water temperature (29oC, pH (7.5 and hardness (225 mgL-1 for 12 weeks. Waterborne and dietary exposures caused significantly variable accumulation of metals in three fish species that followed Zn>Ni>Cd>Co>Cu. Fish liver showed significantly higher tendency to accumulate Cu (69.64±25.35 µg g-1, Cd (68.93±21.65 µg g-1, Zn (91.46±29.53 µg g-1, Ni (74.64±18.61 µg g-1 and Co (22.65±20.56 µg g-1, followed by that of kidney and gills, with significant differences while muscle and bones exhibited significantly least tendency to accumulate all metals. Labeo rohita (31.63±2.43 µg g-1 and C. mrigala (31.43±13.70 µg g-1 exhibited significantly higher ability to amass metals than that of C. catla (27.96±10.28 µg g-1. Waterborne exposure caused significantly higher accumulation of metals in fish liver (72.69±27.91 µg g-1, followed by that in kidney, gills, skin, muscle, fins and bones with the average concentrations of 45.14±18.70, 39.47±21.13, 30.81±12.64, 22.65±17.34, 22.23±11.74 and 12.14±6.25 µg g-1, respectively. Dietary exposure resulted into significant escalation of metals in fish liver (58.23±32.44 µg g-1 while it was lowest in bones. Waterborne exposure caused significantly higher accumulation of all metals in fish body than that of dietary treatments.

  20. The In Vivo Pericapsular Tissue Response to Modern Polyurethane Breast Implants.

    Science.gov (United States)

    Frame, James; Kamel, Dia; Olivan, Marcelo; Cintra, Henrique

    2015-10-01

    Polyurethane breast implants were first introduced by Ashley (Plast Reconstr Surg 45:421-424, 1970), with the intention of trying to reduce the high incidence of capsular contracture associated with smooth shelled, high gel bleed, silicone breast implants. The sterilization of the polyurethane foam in the early days was questionable. More recently, ethylene oxide (ETO)-sterilized polyurethane has been used in the manufacturing process and this has been shown to reduce the incidence of biofilm. The improved method of attachment of polyurethane onto the underlying high cohesive gel, barrier shell layered, silicone breast implants also encourages bio-integration. Polyurethane covered, cohesive gel, silicone implants have also been shown to reduce the incidence of other problems commonly associated with smooth or textured silicone implants, especially with reference to displacement, capsular contracture, seroma, reoperation, biofilm and implant rupture. Since the introduction of the conical polyurethane implant (Silimed, Brazil) into the United Kingdom in 2009 (Eurosurgical, UK), we have had the opportunity to review histology taken from the capsules of polyurethane implants in three women ranging from a few months to over 3 years after implantation. All implants had been inserted into virgin subfascial, extra-pectoral planes. The results add to the important previously described histological findings of Bassetto et al. (Aesthet Plast Surg 34:481-485, 2010). Five distinct layers are identified and reasons for the development of each layer are discussed. Breast capsule around polyurethane implants, in situ for fifteen and 20 years, has recently been obtained and analysed in Brazil, and the histology has been incorporated into this study. After 20 years, the polyurethane is almost undetectable and capsular contracture may appear. These findings contribute to our understanding of polyurethane implant safety, and give reasoning for a significant reduction in clinical

  1. Polyurethane as a base for a family of tissue equivalent materials

    International Nuclear Information System (INIS)

    Griffith, R.V.

    1980-01-01

    Polyurethane was used as a base material for a wide variety of tissue simulating applications. The technique in fabrication is similar to that of epoxy, however, the end products are generally more flexible for use in applications where flexibility is valuable. The material can be fabricated with relatively small laboratory equipment. The use of polyurethane provides the dosimetrist with the capability of making specific, accurate, on-the-spot tissue equivalent formulations to meet situations which require immediate calibration and response

  2. Blends of natural rubber and polyurethane lattices studied by solid-state NMR

    International Nuclear Information System (INIS)

    Ricardo, Nagila M.P.S.; Franca, Francisco C.F. de; Price, Colin; Heatley, Frank

    2001-01-01

    Molecular mixing in films formed from a mixture of a polyurethane and natural rubber lattices has been studied using 1 H and 13 C solid-state NMR. The techniques employed include 1 H relaxation measurements, and 13 C cross-polarisation and direct excitation methods. The spectra of the blends were essentially a weighted superposition of the spectra of the individual components, indicating that the polyurethane and rubber remained phase-separated in large domains. (author)

  3. Actuators based on polyurethanes with different types of polyol

    Science.gov (United States)

    Lim, Hyun-Ok; Bark, Geong-Mi; Jo, Nam-Ju

    2007-07-01

    This study dealt with the electrostrictive responses of polyurethane (PU) actuators with different microphase separation structure, which was a promising candidate for a material used in polymer actuators. In order to construct PUs with different higher-order structure, we synthesized PUs with different diols; poly(neopentyl glycol adipate) (PNAD), poly(tetramethylene glycol) (PTMG), and poly(dimethyl siloxnae) (PDMS). Synthesized PU was characterized by FT-IR spectroscopy and GPC. Thermal analysis and mechanical properties of PU films were carried out with DSC and UTM, respectively. And PU actuator was formed in a monomorph type which made by carbon black electrodes on the both surfaces of PU film by spin coating method. Actuation behavior was mainly influenced on microphase separation structure and mechanical property of PU. In result, PU actuator with PNAD, polyester urethane, had the largest field-induced displacement.

  4. Microporous polyurethane-acrylamide film cured by electron beam irradiation

    International Nuclear Information System (INIS)

    Ando, Masayuki; Goto, Takakazu; Tsuchiya, Mitsuru; Uryu, Toshiyuki

    1988-01-01

    The morphology and aggregation structure of electron beam (EB)-cured microporous polyurethane-acrylamide film was investigated. The urethane-acrylamide prepolymer was synthesized by the reaction of poly(butylene adipate)diol, diphenylmethane diisocyanate, and N-(hydroxymethyl)acrylamide. It was found from scanning electron microscopy that the urethane-acrylamide film, which was prepared by using a methyl ethyl ketone and dimethylformamide (3:1 v/v) mixture as casting solvent, had a microporous structure with pore size of several micrometers, and that the morphology was fixed by EB irradiation. The pore volume of the EB-cured microporous film was determined to be about 460 mm 3 g -1 by mercury porosimetry. The micropores were not destroyed even after immersing in solvent, possibly because the cured film had high crystallinity and dense crosslinking. Moreover, it was found by X-ray photelectron spectroscopy that terminal portions of urethane-acrylamide were localized at the film surface. (author)

  5. Thermoplastic Polyurethane Elastomer Nanocomposites: Morphology, Thermophysical, and Flammability Properties

    Directory of Open Access Journals (Sweden)

    Wai K. Ho

    2010-01-01

    Full Text Available Novel materials based on nanotechnology creating nontraditional ablators are rapidly changing the technology base for thermal protection systems. Formulations with the addition of nanoclays and carbon nanofibers in a neat thermoplastic polyurethane elastomer (TPU were melt-compounded using twin-screw extrusion. The TPU nanocomposites (TPUNs are proposed to replace Kevlar-filled ethylene-propylene-diene-monomer rubber, the current state-of-the-art solid rocket motor internal insulation. Scanning electron microscopy analysis was conducted to study the char characteristics of the TPUNs at elevated temperatures. Specimens were examined to analyze the morphological microstructure during the pyrolysis reaction and in fully charred states. Thermophysical properties of density, specific heat capacity, thermal diffusivity, and thermal conductivity of the different TPUN compositions were determined. To identify dual usage of these novel materials, cone calorimetry was employed to study the flammability properties of these TPUNs.

  6. Release of CFC-11 from disposal of polyurethane foam waste

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Jensen, M.H.

    2001-01-01

    The halocarbon CFC-11 has extensively been used as a blowing agent for polyurethane (PUR) insulation foams in home appliances and for residential and industrial construction. Release of CFCs is an important factor in the depletion of the ozone layer. For CFC-11 the future atmospheric concentrations...... will mainly depend on the continued release from PUR foams. Little is known about rates and time frames of the CFC release from foams especially after treatment and disposal of foam containing waste products. The CFC release is mainly controlled by slow diffusion out through the PUR. From the literature...... and by reevaluation of an old reported experiment, diffusion coefficients in the range of 0.05-1.7.10(-14) m(2) s(-1) were found reflecting differences in foam properties and experimental designs. Laboratory experiments studying the distribution of CFC in the foam and the short-term releases after shredding showed...

  7. Chain and mirophase-separated structures of ultrathin polyurethane films

    International Nuclear Information System (INIS)

    Kojio, Ken; Yamamoto, Yasunori; Motokucho, Suguru; Furukawa, Mutsuhisa; Uchiba, Yusuke

    2009-01-01

    Measurements are presented how chain and microphase-separated structures of ultrathin polyurethane (PU) films are controlled by the thickness. The film thickness is varied by a solution concentration for spin coating. The systems are PUs prepared from commercial raw materials. Fourier-transform infrared spectroscopic measurement revealed that the degree of hydrogen bonding among hard segment chains decreased and increased with decreasing film thickness for strong and weak microphase separation systems, respectively. The microphase-separated structure, which is formed from hard segment domains and a surrounding soft segment matrix, were observed by atomic force microscopy. The size of hard segment domains decreased with decreasing film thickness, and possibility of specific orientation of the hard segment chains was exhibited for both systems. These results are due to decreasing space for the formation of the microphase-separated structure.

  8. Investigating the influence of conduit residues on polyurethane plates

    Directory of Open Access Journals (Sweden)

    Rachel Faverzani Magnago

    Full Text Available Abstract Converting waste into a product similar to the original one or into another useful product is to save energy, protect natural resources, and bring back to the production cycle what was discarded. In that direction, new polyurethane-based composites have been developed by incorporating 5%, 10%, 15%, and 20% PVC conduit discarded by the construction industry. The objective of this study was to investigate the interaction between the phases of waste incorporation and the effect upon the new material properties. The samples were produced by the polycondensation process. Microstructural analysis revealed a reduction in pore size across the polymer matrix. However, there were no changes in thermal insulation, water absorption, compressive strength, and burning rate tests and in the thermogravimetric analysis and differential scanning calorimetry. The results from this study showed that the replacement of raw material by waste did not affect its properties.

  9. Residual stress in spin-cast polyurethane thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hong; Zhang, Li, E-mail: lizhang@mae.cuhk.edu.hk [Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin N.T., Hong Kong (China); Chow Yuk Ho Technology Centre for Innovative Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong (China)

    2015-01-19

    Residual stress is inevitable during spin-casting. Herein, we report a straightforward method to evaluate the residual stress in as-cast polyurethane thin films using area shrinkage measurement of films in floating state, which shows that the residual stress is independent of radial location on the substrate and decreased with decreasing film thickness below a critical value. We demonstrate that the residual stress is developed due to the solvent evaporation after vitrification during spin-casting and the polymer chains in thin films may undergo vitrification at an increased concentration. The buildup of residual stress in spin-cast polymer films provides an insight into the size effects on the nature of polymer thin films.

  10. Creep of thermoplastic polyurethane reinforced with ozone functionalized carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Z. Zhang

    2012-09-01

    Full Text Available This work focused on the mechanical behavior, especially creep resistance, of thermoplastic polyurethane (TPU filled with ozone-treated multi-walled carbon nanotubes (MWCNTs. It was found that the ozone functionalization of MWCNTs could improve their dispersion and interfacial adhesion to the TPU matrix as proved by scanning electron microscope and Raman spectrometer. It finally contributed to the enhancement of Young’s modulus and yield strength of TPU/MWCNT composites. Moreover, the creep resistance and recovery of MWCNT/TPU composites revealed a significant improvement by incorporating ozone functionalized MWCNTs. The strong interaction between the modified MWCNTs and TPU matrix would enhance the interfacial bonding and facilitate the load transfer, resulting in low creep strain and unrecovered strain.

  11. Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

    Directory of Open Access Journals (Sweden)

    T. Jiříček

    2017-01-01

    Full Text Available Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest flux was achieved with the thinnest membranes and the best energy efficiency was achieved with the thickest membranes. All membranes had salt retention above 99%. Nanotechnology offers the potential to find modern solutions for desalination of waste waters, by introducing new materials with revolutionary properties, but new membranes must be developed according to the target application.

  12. Differential effect of waterborne cadmium exposure on lipid metabolism in liver and muscle of yellow catfish Pelteobagrus fulvidraco

    International Nuclear Information System (INIS)

    Chen, Qi-Liang; Gong, Yuan; Luo, Zhi; Zheng, Jia-Lang; Zhu, Qing-Ling

    2013-01-01

    Highlights: •Cd triggered hepatic lipid accumulation through the improvement of lipogenesis. •Lipid homeostasis in muscle after Cd exposure derived from the down-regulation of both lipogenesis and lipolysis. •Our study determines the mechanism of waterborne Cd exposure on lipid metabolism in fish on a molecular level. •Our study indicates the tissue-specific regulatory effect of lipid metabolism under waterborne Cd exposure. -- Abstract: The present study was conducted to investigate the effect of waterborne cadmium (Cd) exposure on lipid metabolism in liver and muscle of juvenile yellow catfish Pelteobagrus fulvidraco. Yellow catfish were exposed to 0 (control), 0.49 and 0.95 mg Cd/l, respectively, for 6 weeks, the lipid deposition, Cd accumulation, the activities and expression level of several enzymes as well as the mRNA expression of transcription factors involved in lipid metabolism in liver and muscle were determined. Waterborne Cd exposure reduced growth performance, but increased Cd accumulation in liver and muscle. In liver, lipid content, the activities and the mRNA expression of lipogenic enzymes (6-phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), fatty acid synthetase (FAS)) and lipoprotein lipase (LPL) activity increased with increasing waterborne Cd concentrations. However, the mRNA expressions of LPL and peroxisome proliferators-activated receptor (PPAR) α were down-regulated by Cd exposure. Carnitine palmitoyltransferase 1 (CPT1) activity as well as the mRNA expressions of CPT1 and PPARγ showed no significant differences among the treatments. In muscle, lipid contents showed no significant differences among the treatments. The mRNA expression of 6PGD, FAS, CPT1, LPL, PPARα and PPARγ were down-regulated by Cd exposure. Thus, our study indicated that Cd triggered hepatic lipid accumulation through the improvement of lipogenesis, and that lipid homeostasis in muscle was probably conducted by the down

  13. Differential effect of waterborne cadmium exposure on lipid metabolism in liver and muscle of yellow catfish Pelteobagrus fulvidraco

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qi-Liang; Gong, Yuan [Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan 430070 (China); Luo, Zhi, E-mail: luozhi99@mail.hzau.edu.cn [Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan 430070 (China); Zheng, Jia-Lang; Zhu, Qing-Ling [Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan 430070 (China)

    2013-10-15

    Highlights: •Cd triggered hepatic lipid accumulation through the improvement of lipogenesis. •Lipid homeostasis in muscle after Cd exposure derived from the down-regulation of both lipogenesis and lipolysis. •Our study determines the mechanism of waterborne Cd exposure on lipid metabolism in fish on a molecular level. •Our study indicates the tissue-specific regulatory effect of lipid metabolism under waterborne Cd exposure. -- Abstract: The present study was conducted to investigate the effect of waterborne cadmium (Cd) exposure on lipid metabolism in liver and muscle of juvenile yellow catfish Pelteobagrus fulvidraco. Yellow catfish were exposed to 0 (control), 0.49 and 0.95 mg Cd/l, respectively, for 6 weeks, the lipid deposition, Cd accumulation, the activities and expression level of several enzymes as well as the mRNA expression of transcription factors involved in lipid metabolism in liver and muscle were determined. Waterborne Cd exposure reduced growth performance, but increased Cd accumulation in liver and muscle. In liver, lipid content, the activities and the mRNA expression of lipogenic enzymes (6-phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), fatty acid synthetase (FAS)) and lipoprotein lipase (LPL) activity increased with increasing waterborne Cd concentrations. However, the mRNA expressions of LPL and peroxisome proliferators-activated receptor (PPAR) α were down-regulated by Cd exposure. Carnitine palmitoyltransferase 1 (CPT1) activity as well as the mRNA expressions of CPT1 and PPARγ showed no significant differences among the treatments. In muscle, lipid contents showed no significant differences among the treatments. The mRNA expression of 6PGD, FAS, CPT1, LPL, PPARα and PPARγ were down-regulated by Cd exposure. Thus, our study indicated that Cd triggered hepatic lipid accumulation through the improvement of lipogenesis, and that lipid homeostasis in muscle was probably conducted by the down

  14. Study on heat transfer performance of water-borne and oily graphene coatings using anti-/de-icing component

    Science.gov (United States)

    Chen, Long; Zhang, Yidu; Wu, Qiong; Jie, Zhang

    2018-02-01

    A graphene coating anti-/de-icing experiment was proposed by employing water-borne and oily graphene coatings on the composite material anti-/de-icing component. Considering the characteristics of helicopter rotor sensitivity to icing, a new graphene coating enhancing thermal conductivity of anti-/de-icing component was proposed. The anti-/de-icing experiment was conducted to validate the effectiveness of graphene coating. The results of the experiment show that the graphene coatings play a prominent role in controlling the heat transfer of anti-/de-icing component. The anti-/de-icing effect of oily graphene coating is superior to water-borne graphene.

  15. Vascularization and tissue infiltration of a biodegradable polyurethane matrix

    Science.gov (United States)

    Ganta, Sudhakar R.; Piesco, Nicholas P.; Long, Ping; Gassner, Robert; Motta, Luis F.; Papworth, Glenn D.; Stolz, Donna B.; Watkins, Simon C.; Agarwal, Sudha

    2016-01-01

    Urethanes are frequently used in biomedical applications because of their excellent biocompatibility. However, their use has been limited to bioresistant polyurethanes. The aim of this study was to develop a nontoxic biodegradable polyurethane and to test its potential for tissue compatibility. A matrix was synthesized with pentane diisocyanate (PDI) as a hard segment and sucrose as a hydroxyl group donor to obtain a microtextured spongy urethane matrix. The matrix was biodegradable in an aqueous solution at 37°C in vitro as well as in vivo. The polymer was mechanically stable at body temperatures and exhibited a glass transition temperature (Tg) of 67°C. The porosity of the polymer network was between 10 and 2000 µm, with the majority of pores between 100 and 300 µm in diameter. This porosity was found to be adequate to support the adherence and proliferation of bone-marrow stromal cells (BMSC) and chondrocytes in vitro. The degradation products of the polymer were nontoxic to cells in vitro. Subdermal implants of the PDI–sucrose matrix did not exhibit toxicity in vivo and did not induce an acute inflammatory response in the host. However, some foreign-body giant cells did accumulate around the polymer and in its pores, suggesting its degradation is facilitated by hydrolysis as well as by giant cells. More important, subdermal implants of the polymer allowed marked infiltration of vascular and connective tissue, suggesting the free flow of fluids and nutrients in the implants. Because of the flexibility of the mechanical strength that can be obtained in urethanes and because of the ease with which a porous microtexture can be achieved, this matrix may be useful in many tissue-engineering applications. PMID:12522810

  16. Estimation of efficiency of hydrotransport pipelines polyurethane coating application in comparison with steel pipelines

    Science.gov (United States)

    Aleksandrov, V. I.; Vasilyeva, M. A.; Pomeranets, I. B.

    2017-10-01

    The paper presents analytical calculations of specific pressure loss in hydraulic transport of the Kachkanarsky GOK iron ore processing tailing slurry. The calculations are based on the results of the experimental studies on specific pressure loss dependence upon hydraulic roughness of pipelines internal surface lined with polyurethane coating. The experiments proved that hydraulic roughness of polyurethane coating is by the factor of four smaller than that of steel pipelines, resulting in a decrease of hydraulic resistance coefficients entered into calculating formula of specific pressure loss - the Darcy-Weisbach formula. Relative and equivalent roughness coefficients are calculated for pipelines with polyurethane coating and without it. Comparative calculations show that hydrotransport pipelines polyurethane coating application is conductive to a specific energy consumption decrease in hydraulic transport of the Kachkanarsky GOC iron ore processing tailings slurry by the factor of 1.5. The experiments were performed on a laboratory hydraulic test rig with a view to estimate the character and rate of physical roughness change in pipe samples with polyurethane coating. The experiments showed that during the following 484 hours of operation, roughness changed in all pipe samples inappreciably. As a result of processing of the experimental data by the mathematical statistics methods, an empirical formula was obtained for the calculation of operating roughness of polyurethane coating surface, depending on the pipeline operating duration with iron ore processing tailings slurry.

  17. Optically active polyurethane@indium tin oxide nanocomposite: Preparation, characterization and study of infrared emissivity

    International Nuclear Information System (INIS)

    Yang, Yong; Zhou, Yuming; Ge, Jianhua; Yang, Xiaoming

    2012-01-01

    Highlights: ► Silane coupling agent of KH550 was used to connect the ITO and polyurethanes. ► Infrared emissivity values of the hybrids were compared and analyzed. ► Interfacial synergistic action and orderly secondary structure were the key factors. -- Abstract: Optically active polyurethane@indium tin oxide and racemic polyurethane@indium tin oxide nanocomposites (LPU@ITO and RPU@ITO) were prepared by grafting the organics onto the surfaces of modified ITO nanoparticles. LPU@ITO and RPU@ITO composites based on the chiral and racemic tyrosine were characterized by FT-IR, UV–vis spectroscopy, X-ray diffraction (XRD), SEM, TEM, and thermogravimetric analysis (TGA), and the infrared emissivity values (8–14 μm) were investigated in addition. The results indicated that the polyurethanes had been successfully grafted onto the surfaces of ITO without destroying the crystalline structure. Both composites possessed the lower infrared emissivity values than the bare ITO nanoparticles, which indicated that the interfacial interaction had great effect on the infrared emissivity. Furthermore, LPU@ITO based on the optically active polyurethane had the virtue of regular secondary structure and more interfacial synergistic actions between organics and inorganics, thus it exhibited lower infrared emissivity value than RPU@ITO based on the racemic polyurethane.

  18. Morphology and damping behavior of polyurethane/PMMA simultaneous interpenetrating networks

    Directory of Open Access Journals (Sweden)

    Wang S.H.

    2001-01-01

    Full Text Available A series of polyurethane/PMMA simultaneous interpenetrating networks (SINs with various hard segment contents (X in the polyurethane phase (X = 15.5 to 36.5% in polyurethane and wide range of polyurethane (PU to polyacrylate (PA ratio (PU/PA = 20:80 to 80:20 were prepared, and the damping and mechanical properties of these materials were studied. The damping of polyurethane soft phase was increased and shifted to lower temperature with increased content of PA vitreous phase. The mechanical properties were improved with increasing PA contents. The results show that PA and the polyurethane hard segment interaction play a special role in chain interpenetration density and its magnitude is revealed by the decreased dispersed domain size observed by scanning electron microscopy (SEM and increased loss area as measured by dynamic mechanical thermal analysis (DMTA. When the weight ratio of PU/PA was 40:60, the resulting SIN materials possessed better damping properties, independent of X concentration.

  19. Presence of Biofilms on Polyurethane-Coated Breast Implants: Preliminary Results.

    Science.gov (United States)

    Rieger, Ulrich M; Djedovic, Gabriel; Pattiss, Alexander; Raschke, Gregor F; Frei, Reno; Pierer, Gerhard; Trampuz, Andrej

    2016-01-01

    Polyurethane-coated breast implants seem to be associated with lower medium- and long-term capsular contracture rates in comparison to textured or smooth implant surfaces. Although the etiology of capsular contracture is uncertain, bacterial biofilms have been suggested to trigger chronic peri-implant inflammation, eventually leading to capsular contracture. It is unknown whether polyurethane-coated implants are less prone to biofilm colonization than other implant surfaces. We extracted data from patient records included in a prospective cohort between 2008 and 2011. All patients who underwent removal of polyurethane-coated implants were included in this current study and screened for presence of biofilms by sonication. In addition, implant- and patient-related data were analyzed. Of the ten included polyurethane-coated breast implants, six had been inserted for reconstructive purposes and four for aesthetic reasons. The median implant indwelling time was 28.3 mo. Overall, sonication cultures were positive in 50% of implants. Propionibacterium acnes and coagulase-negative staphylococci were the predominant pathogens isolated from biofilm cultures. Like other implant surfaces, polyurethane-coated implants are prone to biofilm colonization. Further investigations are needed to determine why capsular contracture rates seem to be lower in polyurethane implants than in other implant surfaces. Notably, in this study, 40% of the implants were explanted from breasts with severe capsular contracture.

  20. Synthesis and Application of Jatropha Oil based Polyurethane as Paint Coating Material

    Directory of Open Access Journals (Sweden)

    Zainal Alim Mas’ud

    2012-08-01

    Full Text Available Recently, the use of renewable sources in the preparation of various industrial materials has been revitalized in response to environmental concerns. Natural oils are considered to be the most important genre of renewable sources. Jatropha curcas oil (JPO based polyol is an alternative material that may possibly replace petrochemical-based polyol for polyurethane coating material. Polyurethane was synthesized by reacting JPO-based polyol with isocyanate. To produce JPO-based polyol, JPO was first epoxidized to form epoxidized J. curcas oil (EJP, subsequently it was converted to polyol by the opening ring reaction with acrylic acid (AA using triethylamine (TEA as a catalyst. The JPO-based polyurethane film resulting from this study is compared with polyurethane film from commercial polyol for gloss, hardness, and adhesion quality. The result showed that the source of polyol has an influence on gloss, hardness, and adhesion of polyurethane film, but the differences with using isocyanate has less influence. Using visual observation, polyurethane film produced from L.OHV polyol, H.OHV polyol and commercial polyol have similar quality.

  1. Flexible camphor diamond-like carbon coating on polyurethane to prevent Candida albicans biofilm growth.

    Science.gov (United States)

    Santos, Thaisa B; Vieira, Angela A; Paula, Luciana O; Santos, Everton D; Radi, Polyana A; Khouri, Sônia; Maciel, Homero S; Pessoa, Rodrigo S; Vieira, Lucia

    2017-04-01

    Camphor was incorporated in diamond-like carbon (DLC) films to prevent the Candida albicans yeasts fouling on polyurethane substrates, which is a material commonly used for catheter manufacturing. The camphor:DLC and DLC film for this investigation was produced by plasma enhanced chemical vapor deposition (PECVD), using an apparatus based on the flash evaporation of organic liquid (hexane) containing diluted camphor for camphor:DLC and hexane/methane, mixture for DLC films. The film was deposited at a low temperature of less than 25°C. We obtained very adherent camphor:DLC and DLC films that accompanied the substrate flexibility without delamination. The adherence of camphor:DLC and DLC films on polyurethane segments were evaluated by scratching test and bending polyurethane segments at 180°. The polyurethane samples, with and without camphor:DLC and DLC films were characterized by Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and optical profilometry. Candida albicans biofilm formation on polyurethane, with and without camphor:DLC and DLC, was assessed. The camphor:DLC and DLC films reduced the biofilm growth by 99.0% and 91.0% of Candida albicans, respectively, compared to bare polyurethane. These results open the doors to studies of functionalized DLC coatings with biofilm inhibition properties used in the production of catheters or other biomedical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. A physiological toxicokinetic model for dermal absorption of waterborne pyrene by trout

    Energy Technology Data Exchange (ETDEWEB)

    Namdari, R.; Law, F.C.P. [Simon Fraser Univ., Burnaby, British Columbia (Canada)

    1995-12-31

    A physiologically-based toxicokinetic (PB-TK) model was developed to describe the disposition of pyrene in trout following a bolus injection into the dorsal aorta. In the present study, the PB-TK model was adapted for dermal absorption of waterborne pyrene by trout. A skin compartment with transdermal flux described mathematically by the permeability-area-concentration product was added to the PB-TK model to allow prediction of pyrene concentrations in target organs and blood on the basis of exposure concentration at the skin surface. Physiologically relevant parameters e.g., organ volume, blood flow rate, and tissue/blood partitioning coefficient which were derived from the model were similar to those reported in the previous publication. The dermal PB-TK model was validated by exposing the trunk of trout (400--500 g) to stagnant water containing 24 ppm pyrene in a specially designed chamber for 4 hr, 24 hr or 48 hr. The trout were sacrificed at the conclusion of pyrene exposure and the tissues analyzed for unchanged pyrene by HPLC. In separate experiments, trout were implanted with dorsal aorta cannuli before the trunks were exposed to stagnant water containing 24 ppm pyrene in the chamber for 4 hr. At specific time intervals during and after pyrene exposure, blood samples were withdrawn through the cannula and analyzed for pyrene by HPLC. The agreement between simulated and experimentally obtained values shows that this model is an appropriate tool to predict dermal absorption of waterborne pyrene by trout.

  3. Rapid Identification of Seven Waterborne Exophiala Species by RCA DNA Padlock Probes.

    Science.gov (United States)

    Najafzadeh, M J; Vicente, V A; Feng, Peiying; Naseri, A; Sun, Jiufeng; Rezaei-Matehkolaei, A; de Hoog, G S

    2018-03-05

    The black yeast genus Exophiala includes numerous potential opportunistic species that potentially cause systematic and disseminated infections in immunocompetent individuals. Species causing systemic disease have ability to grow at 37-40 °C, while others consistently lack thermotolerance and are involved in diseases of cold-blooded, waterborne vertebrates and occasionally invertebrates. We explain a fast and sensitive assay for recognition and identification of waterborne Exophiala species without sequencing. The ITS rDNA region of seven Exophiala species (E. equina, E. salmonis, E. opportunistica, E. pisciphila, E. aquamarina, E. angulospora and E. castellanii) along with the close relative Veronaea botryosa was sequenced and aligned for the design of specific padlock probes for the detection of characteristic single-nucleotide polymorphisms. The assay demonstrated to successfully amplify DNA of target fungi, allowing detection at the species level. Amplification products were visualized on 1% agarose gels to confirm specificity of probe-template binding. Amounts of reagents were reduced to prevent the generation of false positive results. The simplicity, tenderness, robustness and low expenses provide padlock probe assay (RCA) a definite place as a very practical method among isothermal approaches for DNA diagnostics.

  4. [Waterborne outbreak of gastroenteritis caused by Norovirus transmitted through drinking water].

    Science.gov (United States)

    Godoy, P; Nuín, C; Alsedà, M; Llovet, T; Mazana, R; Domínguez, A

    2006-10-01

    The aim of this study was to conduct an investigation into an outbreak of waterborne disease caused by Norovirus due to the consumption of contaminated drinking water. The first week after the school summer holidays we detected an outbreak of gastroenteritis at a school in Borges Blanques (Lleida, Spain). A retrospective cohort study was carried out to investigate: water consumption and food (six items). We assessed RNA Norovirus by RT-PCR in 6 stool samples. The risk of gastroenteritis was assessed by applying adjusted risk ratio (RRa) analysis at 95% confidence intervals (CI). The overall attack rate was 45% (96/213). The main symptoms were: abdominal pain, 88.4% (84/95); nausea, 65.9% (62/94), and vomiting, 64.6% (62/96). The consumption of school drinking water was statistically associated with the disease (RRa: 2.8; 95% CI: 1.3-6.2). The school water tank was dirty, but this drinking water was qualified as potable. Six stool samples gave positive results for Norovirus. Norovirus caused this waterborne outbreak of gastroenteritis transmitted through treated drinking water. It should be obligatory to regularly clean school drinking water deposit tanks, especially after the summer holidays.

  5. A status survey of common water-borne diseases in desert city Bikaner (NW Rajasthan, India).

    Science.gov (United States)

    Saxena, M M; Chhabra, Chetna

    2004-03-01

    Water is scarce and, in general, a low quality resource in desert areas and the Indian desert is no exception. With this in view, the present study was taken up to survey the status of common water-borne diseases epidemiological trends in the desert city Bikaner (NW Rajasthan). In the city, 15.5 per cent population and 44.5 per cent families were found to suffer from one or more common water-borne diseases including amoebiasis, diarrhoea, dysentery, jaundice and typhoid. No case of fluorosis was recorded. The highest incidence was that of diarrhoea (5.4 per cent population). The worst affected and safe zones in the city were identified and the trends of different diseases in different zones of the city are discussed. The highest incidence of diseases was noted during summer (58.8 per cent) followed by winter (34.1 per cent) and monsoon (7.0 per cent). Relationship of diseases with population attributes like age, education, economy and family size are also discussed. Attributes for contamination of drinking water have been tried to identify and safety measures suggested.

  6. Evolutionary Control of Infectious Disease: Prospects for Vectorborne and Waterborne Pathogens

    Directory of Open Access Journals (Sweden)

    Paul W Ewald

    1998-09-01

    Full Text Available Evolutionary theory may contribute to practical solutions for control of disease by identifying interventions that may cause pathogens to evolve to reduced virulence. Theory predicts, for example, that pathogens transmitted by water or arthropod vectors should evolve to relatively high levels of virulence because such pathogens can gain the evolutionary benefits of relatively high levels of host exploitation while paying little price from host illness. The entrance of Vibrio cholerae into South America in 1991 has generated a natural experiment that allows testing of this idea by determining whether geographic and temporal variations in toxigenicity correspond to variation in the potential for waterborne transmission. Preliminary studies show such correspondences: toxigenicity is negatively associated with access to uncontaminated water in Brazil; and in Chile, where the potential for waterborne transmission is particularly low, toxigenicity of strains declined between 1991 and 1998. In theory vector-proofing of houses should be similarly associated with benignity of vectorborne pathogens, such as the agents of dengue, malaria, and Chagas' disease. These preliminary studies draw attention to the need for definitive prospective experiments to determine whether interventions such as provisioning of uncontaminated water and vector-proofing of houses cause evolutionary reductions in virulence

  7. Water-borne sperm trigger vitellogenic egg growth in two sessile marine invertebrates.

    Science.gov (United States)

    Bishop, J D; Manríquez, P H; Hughes, R N

    2000-06-22

    A diverse array of sessile marine invertebrates mate by passive dispersal of sperm which fertilize the brooded eggs of neighbours. In two such species, a sea-mat (phylum Bryozoa) and an ascidian (phylum Chordata), vitellogenic egg growth is absent in reproductively isolated specimens, but is triggered by a water-borne factor released by conspecifics. In both of these colonial, hermaphroditic species, the active factor can be removed from water by filtration. The effect involves self-/non-self-recognition: water conditioned by a separate subcolony of the same genetic individual does not prompt oocyte growth. In each species, allosperm move from the surrounding water to the ovary and are then stored in close association with the growing oocytes. We concluded that sperm themselves are the water-borne factor that triggers the major phase of female reproductive investment. This mechanism is, to our knowledge, previously undescribed in animals, but has parallels with the initiation of maternal investment in flowering plants following the receipt of compatible pollen. The species studied may be representative of many other aquatic invertebrates which mate in a similar way. The stimulation of egg growth by allosperm could lead to intersexual conflict during oogenesis.

  8. Synthesis and membrane performance characterization of self-emulsified waterborne nitrocellulose dispersion modified with castor oil

    Energy Technology Data Exchange (ETDEWEB)

    Su, Xiuxia; Zhao, Qingxiao, E-mail: 934481965@qq.com; Zhang, Dan; Dong, Wei

    2015-11-30

    Graphical abstract: - Highlights: • Waterborne nitrocellulose dispersion modified with castor oil (CWNC) was synthesized successfully. • It is a kind of environment-friendly coatings, in which volatile organic content (VOC) is near zero. • Castor oil used as an internal crosslinking agent for WNC improved the properties of the coating. • When the mass fraction of castor oil to total reactants is 7%, emulsion and the coating are of the best comprehensive performance. - Abstract: Waterborne nitrocellulose dispersion modified with castor oil (CWNC) was designed and successfully synthesized by self emulsification and reaction among isophorone diisocyanate (IPDI) trimer, dimethylol propionic acid (DMPA), nitrocellulose (NC) and castor oil (C.O.). The CWNC was characterized by transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and thermal gravimetric analysis (TGA), etc. The particle size of CWNC increased with the increase of mass fraction of castor oil to total reactants, ω (C.O.). The morphology of particles is an approximate core–shell structure indicated by TEM. FTIR confirmed that the reactions (i.e. IPDI trimer and castor oil, IPDI trimer and NC) occurred, the NCO groups of IPDI trimer were consumed totally and the backbone of NC was retained. The water contact angle measurements confirmed that introduced castor oil increased hydrophobicity of the film, thereby increasing the contact angle. TGA revealed that the CWNC film had better thermal resistance.

  9. New guidelines for oil spill identification of waterborne petroleum and petroleum products

    Energy Technology Data Exchange (ETDEWEB)

    Faksness, L.G.; Daling, P.S. [SINTEF Energy Research, Trondheim (Norway); Hansen, A.B. [National Environmental Research Inst., Roskilde (Denmark); Kienhuis, P. [RIZA, (Netherlands); Duus, R. [Norwegian Standard Association (Norway)

    2005-07-01

    Advances in interpretive and analytical methods have opened the possibility to improve the existing Nordtest methodology for oil spill identification which was developed in 1991 under the Nordic Council of Ministers. In 2002, the European Committee for Standardization (CEN) established 2 working groups to revise the Nordtest Methodology into the following 2 CEN guidelines: (1) oil spill identification which includes waterborne and petroleum products, and (2) oil spill identification which in addition to including waterborne petroleum and petroleum products, includes analytical methodology and interpretation of results. The revised methodology includes a protocol/decision chart that has 3 tiered levels of analyses and data treatment. The methodology relies on the characterization of diagnostic ratios. The CEN working group intends to use the guidelines as a basis for a national oil spill identification protocol in each European country and for further international use. The methodology can be applied to oil samples of petrogenic origin with boiling points above 200 degrees C, such as crude oils, diesel fuel oils, residual bunker oils, lubricants, and mixtures of oily bilge and sludge samples. It is not intended for automotive gasolines or other light petroleum products. The method has been implemented in most forensic laboratories in Europe and has successfully differentiated between oils from a spill and possible pollution sources. 19 refs., 4 tabs., 10 figs.

  10. A Waterborne Gastroenteritis Outbreak Caused by Norovirus GII.17 in a Hotel, Hebei, China, December 2014.

    Science.gov (United States)

    Qin, Meng; Dong, Xiao-Gen; Jing, Yan-Yan; Wei, Xiu-Xia; Wang, Zhao-E; Feng, Hui-Ru; Yu, Hong; Li, Jin-Song; Li, Jie

    2016-09-01

    Norovirus (NoV) is responsible for an estimated 90 % of all epidemic nonbacterial outbreaks of gastroenteritis worldwide. Waterborne outbreaks of NoV are commonly reported. A novel GII.17 NoV strain emerged as a major cause of gastroenteritis outbreaks in China during the winter of 2014/2015. During this time, an outbreak of gastroenteritis occurred at a hotel in a ski park in Hebei Province, China. Epidemiological investigations indicated that one water well, which had only recently been in use, was the probable source. GII.17 NoV was detected by real-time reverse-transcription polymerase chain reaction from samples taken from cases, from concentrated water samples from water well, and from the nearby sewage settling tank. Nucleotide sequences of NoV extracted from clinical and water specimens were genetically identical and had 99 % homology with Beijing/CHN/2015. All epidemiological data indicated that GII.17 NoV was responsible for this outbreak. This is the first reported laboratory-confirmed waterborne outbreak caused by GII.17 NoV genotype in China. Strengthening management of well drinking water and systematica monitoring of NoV is essential for preventing future outbreaks.

  11. New guidelines for oil spill identification of waterborne petroleum and petroleum products

    International Nuclear Information System (INIS)

    Faksness, L.G.; Daling, P.S.; Hansen, A.B.; Kienhuis, P.; Duus, R.

    2005-01-01

    Advances in interpretive and analytical methods have opened the possibility to improve the existing Nordtest methodology for oil spill identification which was developed in 1991 under the Nordic Council of Ministers. In 2002, the European Committee for Standardization (CEN) established 2 working groups to revise the Nordtest Methodology into the following 2 CEN guidelines: (1) oil spill identification which includes waterborne and petroleum products, and (2) oil spill identification which in addition to including waterborne petroleum and petroleum products, includes analytical methodology and interpretation of results. The revised methodology includes a protocol/decision chart that has 3 tiered levels of analyses and data treatment. The methodology relies on the characterization of diagnostic ratios. The CEN working group intends to use the guidelines as a basis for a national oil spill identification protocol in each European country and for further international use. The methodology can be applied to oil samples of petrogenic origin with boiling points above 200 degrees C, such as crude oils, diesel fuel oils, residual bunker oils, lubricants, and mixtures of oily bilge and sludge samples. It is not intended for automotive gasolines or other light petroleum products. The method has been implemented in most forensic laboratories in Europe and has successfully differentiated between oils from a spill and possible pollution sources. 19 refs., 4 tabs., 10 figs

  12. Waterborne toxoplasmosis investigated and analysed under hydrogeological assessment: new data and perspectives for further research.

    Science.gov (United States)

    Vieira, Flávia Pereira; Alves, Maria da Glória; Martins, Livia Mattos; Rangel, Alba Lucínia Peixoto; Dubey, Jitender Prakash; Hill, Dolores; Bahia-Oliveira, Lilian Maria Garcia

    2015-11-01

    We present a set of data on human and chicken Toxoplasma gondii seroprevalence that was investigated and analysed in light of groundwater vulnerability information in an area endemic for waterborne toxoplasmosis in Brazil. Hydrogeological assessment was undertaken to select sites for water collection from wells for T. gondii oocyst testing and for collecting blood from free-range chickens and humans for anti-T. gondii serologic testing. Serologic testing of human specimens was done using conventional commercial tests and a sporozoite-specific embryogenesis-related protein (TgERP), which is able to differentiate whether infection resulted from tissue cysts or oocysts. Water specimens were negative for the presence of viable T. gondii oocysts. However, seroprevalence in free-range chickens was significantly associated with vulnerability of groundwater to surface contamination (p toxoplasmosis in light of groundwater vulnerability information associated with prevalence in humans estimated by oocyst antigens recognition have implications for the potential role of hydrogeological assessment in researching waterborne toxoplasmosis at a global scale.

  13. Synthesis and membrane performance characterization of self-emulsified waterborne nitrocellulose dispersion modified with castor oil

    International Nuclear Information System (INIS)

    Su, Xiuxia; Zhao, Qingxiao; Zhang, Dan; Dong, Wei

    2015-01-01

    Graphical abstract: - Highlights: • Waterborne nitrocellulose dispersion modified with castor oil (CWNC) was synthesized successfully. • It is a kind of environment-friendly coatings, in which volatile organic content (VOC) is near zero. • Castor oil used as an internal crosslinking agent for WNC improved the properties of the coating. • When the mass fraction of castor oil to total reactants is 7%, emulsion and the coating are of the best comprehensive performance. - Abstract: Waterborne nitrocellulose dispersion modified with castor oil (CWNC) was designed and successfully synthesized by self emulsification and reaction among isophorone diisocyanate (IPDI) trimer, dimethylol propionic acid (DMPA), nitrocellulose (NC) and castor oil (C.O.). The CWNC was characterized by transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and thermal gravimetric analysis (TGA), etc. The particle size of CWNC increased with the increase of mass fraction of castor oil to total reactants, ω (C.O.). The morphology of particles is an approximate core–shell structure indicated by TEM. FTIR confirmed that the reactions (i.e. IPDI trimer and castor oil, IPDI trimer and NC) occurred, the NCO groups of IPDI trimer were consumed totally and the backbone of NC was retained. The water contact angle measurements confirmed that introduced castor oil increased hydrophobicity of the film, thereby increasing the contact angle. TGA revealed that the CWNC film had better thermal resistance.

  14. Progression of the load of waterborne and intestinal parasitic diseases in the State of Amazonas.

    Science.gov (United States)

    Martins, Marilaine; Lacerda, Marcus Vinícius Guimarães; Monteiro, Wuelton Marcelo; Moura, Marco Antonio Saboia; Santos, Eyde Cristianne Saraiva; Saraceni, Valéria; Saraiva, Maria Graças Gomes

    2015-01-01

    In the State of Amazonas, Brazil, urban expansion together with precarious basic sanitation conditions and human settlement on river banks has contributed to the persistence of waterborne and intestinal parasitic diseases. Time series of the recorded cases of cholera, typhoid fever, hepatitis A and leptospirosis are described, using data from different levels of the surveillance systems. The sources for intestinal parasitosis prevalence data (non-compulsory reporting in Brazil) were Medical Literature Analysis and Retrieval System Online (MEDLINE), Literatura Latino-Americana (LILACS) and the annals of major scientific meetings. Relevant papers and abstracts in all languages were accessed by two independent reviewers. The references cited by each relevant paper were scrutinized to locate additional papers. Despite its initial dissemination across the entire State of Amazonas, cholera was controlled in 1998. The magnitude of typhoid fever has decreased; however, a pattern characterized by eventual outbreaks still remains. Leptospirosis is an increasing cause of concern in association with the annual floods. The overall prevalence of intestinal parasites is high regardless of the municipality and the characteristics of areas and populations. The incidence of hepatitis A has decreased over the past decade. A comparison of older and recent surveys shows that the prevalence of intestinal parasitic diseases has remained constant. The load of waterborne and intestinal parasitic diseases ranks high among the health problems present in the State of Amazonas. Interventions aiming at basic sanitation and vaccination for hepatitis A were formulated and implemented, but assessment of their effectiveness in the targeted populations is still needed.

  15. Risk of waterborne illness via drinking water in the United States.

    Science.gov (United States)

    Reynolds, Kelly A; Mena, Kristina D; Gerba, Charles P

    2008-01-01

    Outbreaks of disease attributable to drinking water are not common in the U.S., but they do still occur and can lead to serious acute, chronic, or sometimes fatal health consequences, particularly in sensitive and immunocompromised populations. From 1971 to 2002, there were 764 documented waterborne outbreaks associated with drinking water, resulting in 575,457 cases of illness and 79 deaths (Blackburn et al. 2004; Calderon 2004); however, the true impact of disease is estimated to be much higher. If properly applied, current protocols in municipal water treatment are effective at eliminating pathogens from water. However, inadequate, interrupted, or intermittent treatment has repeatedly been associated with waterborne disease outbreaks. Contamination is not evenly distributed but rather affected by the number of pathogens in the source water, the age of the distribution system, the quality of the delivered water, and climatic events that can tax treatment plant operations. Private water supplies are not regulated by the USEPA and are generally not treated or monitored, although very few of the municipal systems involved in documented outbreaks exceeded the USEPA's total coliform standard in the preceding 12 mon (Craun et al. 2002). We provide here estimates of waterborne infection and illness risks in the U.S. based on the total number of water systems, source water type, and total populations exposed. Furthermore, we evaluated all possible illnesses associated with the microbial infection and not just gastroenteritis. Our results indicate that 10.7 M infections/yr and 5.4 M illnesses/yr occur in populations served by community groundwater systems; 2.2 M infections/yr and 1.1 M illnesses/yr occur in noncommunity groundwater systems; and 26.0 M infections/yr and 13.0 M illnesses/yr occur in municipal surface water systems. The total estimated number of waterborne illnesses/yr in the U.S. is therefore estimated to be 19.5 M/yr. Others have recently estimated

  16. Effects of waterborne Fe(II) on juvenile turbot Scophthalmus maximus: analysis of respiratory rate, hematology and gill histology

    Science.gov (United States)

    Wu, Zhihao; You, Feng; Liu, Hongjun; Liu, Mengxia; Li, Jun; Zhang, Peijun

    2012-03-01

    The concentration of Fe(II) is high in some groundwater supplies used in turbot culture, and the toxicity of waterborne Fe(II) is unknown. We investigated the stress responses of juvenile turbot, Scophthalmus maximus, exposed to Fe(II) of different concentrations (0.01, 0.05, 0.1, 0.5, 1, and 2 mg/L) for 1, 7, 14, and 28 d, under the same ambient conditions of other parameters. Changes in respiratory rate, hematological parameters, and gill structure were determined. The results show that waterborne Fe(II) did not cause severe hematological perturbation to turbot. A low-medium Fe(II) concentration (lower than 0.1 mg/L) could boost the respiratory rate, and caused no or very limited damage to fish. A high Fe(II) concentration (0.1 mg/L or higher), however, caused gill damage, such as vacuoles in branchial lamellae, epithelial necrosis, and hypertrophy of epithelial cells, and even death after extended exposure time. Therefore, excess waterborne Fe(II) and long-term exposure to Fe(II) could be responsible for poor growth and high mortality of turbot in culture. The concentration of waterborne Fe(II) in turbot culture should be kept below 0.1 mg/L.

  17. Risk-based approach to appraise valve closure in the clam Corbicula fluminea in response to waterborne metals

    International Nuclear Information System (INIS)

    Liao, C.-M.; Jou, L.-J.; Chen, B.-C.

    2005-01-01

    We developed a risk-based approach to assess how the valve closure behavior of Asiatic clam Corbicula fluminea responds to waterborne copper (Cu) and cadmium (Cd). We reanalyzed the valve closure response data from published literature to reconstruct the response time-dependent dose-response profiles based on an empirical three-parameter Hill equation model. We integrated probabilistic exposure profiles of measured environmental Cu and Cd concentrations in the western coastal areas of Taiwan with the reconstructed dose-response relationships at different integration times of response to quantitatively estimate the valve response risk. The risk assessment results implicate exposure to waterborne Cu and Cd may pose no significant risk to clam valve activity in the short-time response periods (e.g., <30 min), yet a relative high risk for valve closure response to waterborne Cu at response times greater than 120 min is alarming. We successfully linked reconstructed dose-response profiles and EC50-time relationships associated with the fitted daily valve opening/closing rhythm characterized by a three-parameter lognormal function to predict the time-varying bivalve closure rhythm response to waterborne metals. We parameterized the proposed predictive model that should encourage a risk-management framework for discussion of future design of biological monitoring systems. - A model was developed to link valve closure in clams to concentrations of metals in water

  18. The effects of ozonation on select waterborne steroid hormones in recirculation aquaculture systems containing sexually mature Atlantic salmon Salmo salar

    Science.gov (United States)

    A controlled 3-month study was conducted in 6 replicated water recirculation aquaculture systems (RAS) containing a mixture of sexually mature and immature Atlantic salmon Salmo salar to determine whether water ozonation is associated with a reduction in waterborne hormones. Post-smolt Atlantic salm...

  19. Anticorrosive performance of waterborne epoxy coatings containing water-dispersible hexagonal boron nitride (h-BN) nanosheets

    Science.gov (United States)

    Cui, Mingjun; Ren, Siming; Chen, Jia; Liu, Shuan; Zhang, Guangan; Zhao, Haichao; Wang, Liping; Xue, Qunji

    2017-03-01

    Homogenous dispersion of hexagonal boron nitride (h-BN) nanosheets in solvents or in the polymer matrix is crucial to initiate their many applications. Here, homogeneous dispersion of hexagonal boron nitride (h-BN) in epoxy matrix was achieved with a water-soluble carboxylated aniline trimer derivative (CAT-) as a dispersant, which was attributed to the strong π-π interaction between h-BN and CAT-, as proved by Raman and UV-vis spectra. Transmission electron microscopy (TEM) analysis confirmed a random dispersion of h-BN nanosheets in the waterborne epoxy coatings. The deterioration process of water-borne epoxy coating with and without h-BN nanosheets during the long-term immersion in 3.5 wt% NaCl solution was investigated by electrochemical measurements and water absorption test. Results implied that the introduction of well dispersed h-BN nanosheets into waterborne epoxy system remarkably improved the corrosion protection performance to substrate. Moreover, 1 wt% BN/EP composite coated substrate exhibited higher impedance modulus (1.3 × 106 Ω cm2) and lower water absorption (4%) than those of pure waterborne epoxy coating coated electrode after long-term immersion in 3.5 wt% NaCl solution, demonstrating its superior anticorrosive performance. This enhanced anticorrosive performance was mainly ascribed to the improved water barrier property of epoxy coating via incorporating homogeneously dispersed h-BN nanosheets.

  20. Mechanical properties of wood from Pinus sylvestris L. treated with Light Organic Solvent Preservative and with waterborne Copper Azole

    Energy Technology Data Exchange (ETDEWEB)

    Villasante, A.; Laina, R.; Rojas, J. A. M.; Rojas, I. M.; Vignote, S.

    2013-07-01

    Aim of study: To determine the effect on wood from Pinus sylvestris of treatment with preservatives on mechanical properties and to establish the relation between the penetration and compression strenght. Area of study: Spain. Material and methods: 40 samples of defect-free wood from Pinus sylvestris L. were treated with Light Organic Solvent Preservative (Vacsol Azure WR 2601) and 50 with waterborne Copper Azole (Tanalith E 3492). 40 control samples were not treated (water or preservative). Mechanical resistance to static bending, modulus of elasticity and compression strength parallel to the grain were compared with untreated wood. Regression analysis between the penetration and compression strength parallel was done with the samples treated with waterborne preservative. Main results: The results indicate that the treated wood (with either product) presents a statistically significant increase in mechanical resistance in all three mechanical characteristics. The results obtained differ from earlier studies carried out by other authors. There was no correlation between parallel compression strength and the degree of impregnation of the wood with waterborne Copper Azole. The most probable explanation for these results concerns changes in pressure during treatment. The use of untreated control samples instead of samples treated only with water is more likely to produce significant results in the mechanical resistance studies. Research highlights: Treated wood presents a statistically significant increase in MOE, modulus of rupture to static bending and parallel compression strength. There was no correlation between parallel compression strength and the degree of impregnation with waterborne preservative. (Author)