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Sample records for butylenes

  1. Poly(Butylene Succinate) and Poly[(Butylene Succinate)-co-Adipate] Nanocomposites

    CSIR Research Space (South Africa)

    Ojijo, Vincent O

    2012-01-01

    Full Text Available , and properties of nanoclay-containing composites of biodegradable poly(butylene succinate) (PBS) and poly[(butylene succinate)-co-adipate] (PBSA). Various nanocomposite structures arising from the incorporation of layered silicate particles, both pristine...

  2. Poly(butylene succinate-co-butylene adipate)/cellulose nanocrystal composites modified with phthalic anhydride.

    Science.gov (United States)

    Zhang, Xuzhen; Zhang, Yong

    2015-12-10

    As a kind of biomass nanofiller for polymers, cellulose nanocrystal (CNC) has good mechanical properties and reinforcing capability. To improve the compatibility of poly(butylene succinate-co-butylene adipate) (PBSA)/CNC composites, phthalic anhydride was used as a compatilizer during melt mixing, leading to the significant improvement of the mechanical properties and thermal stability of the composites, which is related to the better dispersion of CNC in the composites. The addition of phthalic anhydride could accelerate the crystallization of PBSA component as evidenced by the curves of isothermal crystallization of the composites, but had little effect on the crystalline polymorphs of PBSA component. The addition of phthalic anhydride could strongly improve the hydrophobicity of the composites. The good mechanical properties, fast crystallization and improved hydrophobicity of PBSA/CNC composites with phthalic anhydride are favor to their practical commercial utilization. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Structure-barrier property relationship of biodegradable poly(butylene succinate) and poly[(butylene succinate)-co-(butylene adipate)] nanocomposites: influence of the rigid amorphous fraction.

    Science.gov (United States)

    Charlon, S; Marais, S; Dargent, E; Soulestin, J; Sclavons, M; Follain, N

    2015-11-28

    Composites composed of polyesters, poly(butylene succinate) (PBS) or poly[(butylene succinate)-co-(butylene adipate)] (PBSA), and 5 wt% of montmorillonite (CNa) or organo-modified montmorillonite (C30B) were melt-processed and transformed into films by either compression-molding or extrusion-calendering. XRD, rheological measurements and TEM images clearly indicated that films containing CNa are microcomposites, while nanocomposites were observed for those containing C30B. Using Flash DSC, it was possible, for the first time, not only to measure the heat capacity step at the glass transition of these two materials in their amorphous state, but also to investigate whether the preparation technique influenced the Rigid Amorphous Fraction (RAF) in our PBS- and PBSA-based nanocomposites. In this work, we have successfully shown the correlation between the microstructure of the films and their barrier properties, and especially the role played by the RAF. Indeed, the lowest permeabilities to gases and to water were determined in the films containing the highest RAF in both PBS- and PBSA-based materials.

  4. Substrate Effect on 2,3-Butylene Glycol Production by Rhizopus nigricans and Penicillium expansum1

    Science.gov (United States)

    Fields, M. L.; Richmond, Bonnie

    1967-01-01

    Rhizopus nigricans and Penicillium expansum produced 2,3-butylene glycol which accumulated in natural and artificial media with time. Mycelial mats of P. expansum decreased the quantity of a diacetyl substrate and converted part of this substrate into acetylmethylcarbinol (AMC) and 2,3-butylene glycol. Mycelial mats of P. expansum also decreased AMC substrate with the formation of 2,3-butylene glycol. 2,3-Butylene glycol decreased slightly during incubation with the fungal mat. The formation of AMC was suppressed significantly by cysteine and ascorbic acid. PMID:6080717

  5. Substrate effect on 2,3-butylene glycol production by Rhizopus nigricans and Penicillium expansum.

    Science.gov (United States)

    Fields, M L; Richmond, B

    1967-11-01

    Rhizopus nigricans and Penicillium expansum produced 2,3-butylene glycol which accumulated in natural and artificial media with time. Mycelial mats of P. expansum decreased the quantity of a diacetyl substrate and converted part of this substrate into acetylmethylcarbinol (AMC) and 2,3-butylene glycol. Mycelial mats of P. expansum also decreased AMC substrate with the formation of 2,3-butylene glycol. 2,3-Butylene glycol decreased slightly during incubation with the fungal mat. The formation of AMC was suppressed significantly by cysteine and ascorbic acid.

  6. Effect of organo-modified montmorillonite on poly(butylene succinate/poly(butylene adipate-co-terephthalate nanocomposites

    Directory of Open Access Journals (Sweden)

    2010-07-01

    Full Text Available The composite material based on poly(butylene succinate (PBS, poly(butylene adipate-co-terephthalate (PBAT and organo-modified montmorillonite (OMMT were prepared by melt blending technique and characterized. Sodium montmorillonite (Na-MMT was successfully modified by octadecylammonium (ODA and dimethyldioctadecylammonium (DDOA salts to become OMMT through cation exchange technique which is shown by the increase of basal spacing of clay by XRD. The addition of the OMMT to the PBS/PBAT blends produced nanocomposites which is proved by XRD and TEM. Tensile tests showed increase in tensile strength and modulus which is attributed to the existence of strong interactions between PBS/PBAT and clay, particularly with OMMT. Highest tensile strength of nanocomposite was observed at 1 wt% of OMMT incorporated. TGA study showed that the thermal stability of the blend increased after the addition of clays. SEM micrographs of the fracture surfaces show that the morphology of the blend becomes homogeneous and smoother with presence of OMMT.

  7. Multifunctional nanobiocomposite of Poly[(butylene succinate)-co-adipate] and clay

    CSIR Research Space (South Africa)

    Al-Thabaiti, SA

    2015-03-01

    Full Text Available The processing and characterization of multifunctional nanobiocomposite of biodegradable poly[(butylene succinate)-co-adipate] (PBSA) and organically modified synthetic fluorine mica (OSFM) are reported. The nanobiocomposite of PBSA with OSFM...

  8. Removal of propylene and butylene as individual compounds with compost and wood chip biofilters.

    Science.gov (United States)

    Rani, Madhu; Sattler, Melanie L

    2011-05-01

    Propylene and butylene are highly reactive volatile organic compounds (HRVOCs) in terms of ground-level ozone formation. This study examined the effectiveness of biofiltration in removing propylene and butylene as separate compounds. Specific objectives were (1) to measure maximum removal efficiencies for propylene and butylene and the corresponding microbial acclimation times, which will be useful in the design of future biofilters for removal of these compounds; (2) to compare removal efficiencies of propylene and butylene for different ratios of compost/hard wood-chip media; and (3) to identify the microorganisms responsible for propylene and butylene degradation. Two laboratory-scale polyvinyl chloride biofilter columns were filled with 28 in. of biofilter media (compost/wood-chip mixtures of 80:20 and 50:50 ratios). Close to 100% removal efficiency was obtained for propylene for inlet concentrations ranging from 2.9 x 10(4) to 6.3 x 10(4) parts per million (ppm) (232-602 g/m3-hr) and for butylene for inlet concentrations ranging from 91 to 643 ppm (1.7-13.6 g/m3-hr). The microbial acclimation period to attain 100% removal efficiency was 12-13 weeks for both compounds. The lack of similar microbial species in the fresh and used media likely accounts for the long acclimation time required. Both ratios of compost/wood chips (80:20 and 50:50) gave similar results. During the testing, media pH increased slightly from 7.1 to 7.5-7.7. None of the species in the used media that treated butylene were the same as those in the used media that treated propylene, indicating that different microbes are adept at degrading the two compounds.

  9. Preparation of biodegradable porous poly(butylene succinate microspheres

    Directory of Open Access Journals (Sweden)

    Pepić Dragana

    2008-01-01

    Full Text Available The aim of this study was to determine the optimal conditions for the fabrication of porous microspheres based on poly(butylene succinate, PBS. The biodegradable non-porous PBS microspheres were prepared by the oil-in-water (o/w emulsion solvent evaporation method using poly(vinyl alcohol, PVA, as the surfactant. Fabrication conditions, such as stirring rate, organic/aqueous ratio, PBS concentration and surfactant (PVA concentration, which have an important influence on both the particle size and the morphology of the microspheres, were varied. Scanning electron microscopy, SEM, observations confirmed the size, size distribution and surface morphology of the microspheres. The optimal conditions for the preparation of the non-porous microspheres were found to be: concentration the PBS solution, 10 mass%; PVA concentration, 1 mass%; the organic/ aqueous ratio CHCl3/H2O = 1/20 and stirring rate 800 rpm. Porous PBS microspheres were fabricated under the optimal conditions using various amounts of hexane and poly(ethylene oxide, PEO, as porogens. The influence of the amount of porogen on the pore size and the particle size was investigated using SEM and the apparent density. The microspheres exhibited various porosities and the pore sizes. The average particle size of the microspheres with PEO as the porogen was from 100 to 122μm and that of the microspheres with hexane as the porogen was from 87 to 97μm. The apparent density of the porous microspheres with PEO as the porogen, from 0.16 to 0.23 g/cm3, was much smaller than the non-porous microspheres, 0.40 g/cm3. In the in vitro degradation experiments, the porous microspheres were incubated in phosphate buffer solution (pH 7 at 37°C. After incubating for one month, the microspheres showed significant extent of the hydrolytic degradation of the porous PBS microspheres.

  10. Viscoelastic and electrical properties of carbon nanotubes filled poly(butylene succinate)

    CSIR Research Space (South Africa)

    Bandyopadhyay, J

    2014-03-01

    Full Text Available The carbon nanotubes (CNTs)-containing composites of poly(butylene succinate) (PBS) were prepared by melt-blending in a batch mixer with three concentrations by weight of CNTs: 1, 2 and 3 %. State of dispersion-distribution of the CNTs in the PBS...

  11. Incorporation of Isosorbide into Poly(butylene terephthalate) via Solid-State Polymerization

    NARCIS (Netherlands)

    Sablong, R.J.; Duchateau, R.; Konings, C.E.; Wit, de G.; Es, van D.S.; Koelewijn, R.; Haveren, van J.

    2008-01-01

    The biomass-based monomer isosorbide was incorporated into poly(butylene terephthalate) (PBT) by solid-state polymerization (SSP) using the macrodiol monomer BTITB-(OH)2, which consists of isosorbide (I), terephthalic acid (T), and 1,4-butandiol (B) residues. This macromonomer can be synthesized by

  12. Crystallization of poly(ethyleneterephthalate) and poly(butylene terephthalate) modified by diamides

    NARCIS (Netherlands)

    Bouma, K.; Gaymans, R.J.

    2001-01-01

    Poly(ethylene terephthalate) (PET) and poly (butylene terephthalate) have been modified by diamide units (0.1-1 mol%) in an extrusion process and the crystallization behavior studied. The diamides used were: for PET, T2T-dimethyl (N, N-bis(p-carbomethoxybenzoyl)ethanediamine) and for PBT,

  13. Electrospun Nanoporous Poly(butylenes succinate-co-bytylene terephthalate Nonwoven Mats

    Directory of Open Access Journals (Sweden)

    Liang Wang

    2011-01-01

    Full Text Available A traditional Chinese drug “Yunnan Baiyao” is used as an additive in poly(butylenes succinate-co-bytylene terephthalate (PBST solution, which is a kind of biodegradable aliphatic-aromatic copolyesters, to produce microspheres with nanoporosity by electrospinning; the tunable size of nanoporosity can be controlled by changing the voltage applied in the electrospinning process.

  14. Viscoelastic properties of poly(butylene succinate)-co-adipate) nanocomposites

    CSIR Research Space (South Africa)

    Al-Thabaiti, SA

    2015-03-01

    Full Text Available This article reports the viscoelastic properties of poly[(butylene succinate)-co-adipate] (PBSA) nanocomposites. The nanocomposites of PBSA with various loadings of organically modified clay were prepared by melt-mixing in a batch-mixer. The solid...

  15. Gas-permeation properties of poly(ethylene oxide) poly(butylene terephthalate block copolymers

    NARCIS (Netherlands)

    Metz, S.J.; Mulder, M.H.V.; Wessling, Matthias

    2004-01-01

    This paper reports the gas-permeation properties of poly(ethylene oxide) (PEO) poly(butylene terephthalate) (PBT) segmented multiblock copolymers. These block copolymers allow a precise structural modification by the amount of PBT and the PEO segment length, enabling a systematic study of the

  16. Surface Self-Assembly and Properties of Monolayers Formed by Reverse Poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) Triblock Copolymers with Lengthy Hydrophilic Blocks

    DEFF Research Database (Denmark)

    Villar-Alvarez, Eva; Freire, Adriana Cambón; Blanco, Mateo

    2017-01-01

    The surface behavior and properties of several reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers, BO8EO90BO8, BO12EO227BO12, BO14EO378BO14, BO20EO411BO20, and BO21EO385BO21 at the air/water interface have been analyzed by drop tensiometry, Langmuir film balan...

  17. Synthesis by ATRP of poly(ethylene-co-butylene)-block-polystyrene, poly(ethylene-co-butylene)-block-poly(4-acetoxystyrene) and its hydrolysis product poly(ethylene-co-butylene)-block-poly(hydroxystyrene)

    DEFF Research Database (Denmark)

    Jankova, Katja; Kops, Jørgen; Chen, Xianyi

    1999-01-01

    Diblock copolymers of poly(ethylene-co-butylene) and polystyrene or poly(4-acetoxystyrene) are synthesized by atom transfer radical polymerization (ATRP) using a 2-bromopropionic ester macroinitiator prepared from commercial monohydroxyl functional narrow dispersity hydrogenated polybutadiene...... (Kraton Liquid Polymer, L-1203). ATRP carried out in bulk and in xylene solution with cuprous bromide and two different complexing agents 2,2'-bipyridine (bipy) and 1,1,4,7,10,10-hexamethyltriethylenetetraamine (HMTETA) yielded well-defined diblock copolymers with polydispersities around 1,3. The diblock...... copolymer with poly(4-acetoxystyrene) was hydrolyzed to the corresponding poly(4-hydroxystyrene) sequence....

  18. Controlling the biodegradability of poly(butylene succinate-co-butylene adipate) (PBSA) by solvents used in the dried-gel process

    Science.gov (United States)

    Yamazaki, Hana; Kamitabira, Saya; Maeda, Tomoki; Hotta, Atsushi

    Considering an environmentally friendly material, poly(butylene succinate-co-butylene adipate)(PBSA) is one of the attractive biodegradable plastics that can be eventually degraded into H2O and CO2 by neighboring water molecules and microorganisms after the disposal. In order to expand the application of PBSA, the precise control of the biodegradability of PBSA is necessary. In this study, the dried-gel process was introduced to control the biodegradability of PBSA. The dried PBSA gels were prepared by using three different solvents (toluene, cyclohexanone, and o-dichlorobenzene). The scanning electron microscopy (SEM) micrographs revealed that the PBSA prepared by toluene had smaller spherocrystals than the other PBSA dried-gels prepared by cyclohexanone or o-dichlorobenzene. The biodegradability testing by immersing the three types of PBSA in NaOH aq. showed that the percentage of the weight loss of the PBSA produced by toluene was the highest. The results indicated that the microstructures of PBSA could be controlled by changing solvents during the gel preparations, and that the biodegradability of PBSA could therefore be efficiently modified by changing solvents. This work was supported by a Grant-in-Aid for Scientific Research (A) (No. 15H02298 to A.H.) and a Grant-in-Aid for Research Activity Start-up (No.15H06586 to T.M.) from JSPS: KAKENHI\\x9D.

  19. Reactive processing of maleic anhydride-grafted poly(butylene succinate and the compatibilizing effect on poly(butylene succinate nanocomposites

    Directory of Open Access Journals (Sweden)

    Z. A. Mohd Ishak

    2013-04-01

    Full Text Available In this study, maleic anhydride-grafted poly(butylene succinate (PBS-g-MA was synthesized via reactive meltgrafting process using different initiator contents. The grafting efficiency was increased with the initiator content, manifested by the higher degree of grafting in PBS-g-MA. The grafting reaction was confirmed through Fourier transform infrared (FTIR spectroscopy and nuclear magnetic resonance (NMR spectroscopy. Then, PBS-g-MA was incorporated into organo-montmorillonite (OMMT filled poly(butylene succinate (PBS nanocomposites as compatibilizer. Mechanical properties of PBS nanocomposites were enhanced after compatibilized with PBS-g-MA, due to the better dispersion of OMMT in PBS matrix and the improved filler-matrix interfacial interactions. This was verifiable through X-ray diffraction (XRD, transmission electron microscopy (TEM and scanning electron microscopy (SEM. Differential scanning calorimetry (DSC showed that the degree of crystallinity and melting temperature increased after addition of PBS-g-MA. However, the presence of PBS-g-MA did not favor the thermal stability of the nanocomposites, as reported in the thermogravimetry (TGA.

  20. Lenghty reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) polymeric micelles and gels for sustained release of antifungal drugs.

    Science.gov (United States)

    Figueroa-Ochoa, Edgar B; Villar-Alvarez, Eva M; Cambón, Adriana; Mistry, Dharmista; Llovo, José; Attwood, David; Barbosa, Silvia; Soltero, J F Armando; Taboada, Pablo

    2016-08-20

    In this work, we present a detailed study of the potential application of polymeric micelles and gels of four different reverse triblock poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) copolymers (BOnEOmBOn, where n denotes the respective block lengths), specifically BO8EO90BO8, BO14EO378BO14, BO20EO411BO20 and BO21EO385BO21, as effective drug transport nanocarriers. In particular, we tested the use of this kind of polymeric nanostructures as reservoirs for the sustained delivery of the antifungals griseofulvin and fluconazole for oral and topical administration. Polymeric micelles and gels formed by these copolymers were shown to solubilize important amounts of these two drugs and to have a good stability in physiologically relevant conditions for oral or topical administration. These polymeric micellar nanocarriers were able to release drugs in a sustained manner, being the release rate slower as the copolymer chain hydrophobicity increased. Different sustained drug release profiles were observed depending on the medium conditions. Gel nanocarriers were shown to display longer sustained release rates than micellar formulations, with the existence of a pulsatile-like release mode under certain solution conditions as a result of their inner network structure. Certain bioadhesive properties were observed for the polymeric physical gels, being moderately tuned by the length and hydrophobicity of the polymeric chains. Furthermore, polymeric gels and micelles showed activity against the yeast Candida albicans and the mould demartophytes (Trichophyton rubrum and Microsporum canis) and, thus, may be useful for the treatment of different cutaneous fungal infections. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Poly(ethylene-co-butylene) functionalized multi walled carbon nanotubes applied in polypropylene nanocomposites

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Jankova Atanasova, Katja; Marín, Jose Manuel Roman

    2012-01-01

    A novel functionalized multi walled carbon nanotube (MWCNT) was prepared through grafting with α-azido-poly(ethylene-co-butylene) (PEB-N3). The PEB-N3 was prepared through a two step procedure and grafted onto an industrial grade multi walled carbon nanotube (MWCNT) through a highly efficient...... filler had a high degree of discharge from the surface and higher conductivity compared to the pristine filler, illustrating an efficient conductive network in the composites. The composites showed low percolation thresholds of 0.3wt.% (0.15vol.%) as well as improved stability at a range of temperatures...

  2. Crystallization and degradation behaviors of poly(butylene succinate)/poly(Z-L-lysine) composites

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Licheng; Hu, Jun; Ye, Suwen; Wei, Junchao, E-mail: weijunchao@ncu.edu.cn; Chen, Yiwang

    2014-01-10

    Highlights: • A new biodegradable poly(butylene succinate) (PBS)/poly(Z-L-lysine) (PZlys) composites were successfully prepared through physical blend. • PZlys may greatly affected the crystallization behaviors of PBS without changing its crystalline structure. • The degradation speed of PBS may be greatly accelerated by introduction of PZlys in PBS matrix. - Abstract: A new type of biodegradable poly(butylene succinate) (PBS)/poly(Z-L-lysine) (PZlys) composites were prepared. The crystallization behaviors were investigated by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarizing optical microscopy (POM) and the results showed that PZlys can restrict the crystallization of PBS, the crystallization speed of PBS/PZlys were slower than that of PBS, and the crystallization degree of the composites were smaller than that of PBS. However, the WAXD results showed that the incorporation of PZlys did not change the crystalline structure of PBS. The in vitro degradation experiments demonstrated that the degradation speed of the composites were faster than that of PBS. Moreover, the mechanical properties of the composites showed that the composites with a proper composition (for example, 80/20) can keep the mechanical properties of PBS without evident difference, which implied that the composites might be potentially useful as biodegradable materials.

  3. Alternating polyesteramides based on 1,4-butylene terephthalamide: 4. alternating polyesteramides based on glycols (4NT glycol)

    NARCIS (Netherlands)

    Serrano, P.J.M.; Serrano, P.J.M.; Gaymans, R.J.

    1998-01-01

    Polyetheresteramides (PEEAs) have been synthesised in the melt from 1,4-butylene terephthalamide and ethylene or propylene glycols. The ethylene glycols were ethylenediol, diethylene glycol, triethylene glycol and tetraethylene glycol. The propylene glycols were 1,3-propanediol and the mixtures of

  4. Alternating polyesteramides based on 1,4-butylene terephthalamide: 2. alternating polyesteramides based on a single, linear diol (4NTm)

    NARCIS (Netherlands)

    Serrano, P.J.M.; Serrano, P.J.M.; Thuss, E.H.L.; Gaymans, R.J.

    1997-01-01

    Strictly alternating polyesteramides consisting of 1,4-butylene terephthalamide and aliphatic diols have been synthesized in the melt in the presence of a titanium catalyst. The influence of diol length on the thermal and mechanical properties was studied. Depending on its structure, the diol took

  5. Production of rotary jet spun ultrathin fibers of poly-butylene adipate-co-terephthalate (PBAT) filled with nanocomposites

    Science.gov (United States)

    Andrade, P. O.; Santo, A. M. E.; Costa, M. M.; Lobo, A. O.

    2017-07-01

    Composite fibers of bioabsorbable poly-butylene adipate-co-terephthalate (PBAT) reinforced with superhydrophilic carbon nanotubes and hydroxyapatite nanocrystals were obtained by rotary jet spinning technique (RJS). The fibers were morphologically and biologically analyzed and found of potential use as scaffold for hard tissue engineering.

  6. Poly(butylene adipate-co-terephthalate) and sunflower head residue composites: Effects of composition and compatibilization on properties

    Science.gov (United States)

    Utilizing the abundant byproducts generated from processing of agricultural materials has sustainable and cost–saving potential benefits. In this work, Sunflower Head Residues (SHR) in 3 different compositions were introduced into biodegradable Poly(butylene adipate-co-terephthalate) (PBAT) matrices...

  7. Toughening of biodegradable polylactide/poly(butylene succinate-co-adipate) blends via in situ reactive compatibilization

    CSIR Research Space (South Africa)

    Ojijo, Vincent O

    2013-04-01

    Full Text Available Polylactide and poly(butylene succinate-coadipate) (PLA/PBSA) were melt-blended in the presence of triphenyl phosphite (TPP). An increase in the torque during melt mixing was used to monitor the changes in viscosity as compatibilization...

  8. Unique cold-crystallization behavior and kinetics of biodegradable poly[(butylene succinate)-co adipate] nanocomposites: a high speed differential scanning calorimetry study

    CSIR Research Space (South Africa)

    Bandyopadhyay, J

    2014-08-01

    Full Text Available The poly[(butylene succinate)-co-adipate] (PBSA) nanocomposites (PBSANCs) with five different loadings of organoclay were prepared by melt-blending. The morphological investigation revealed that the degree of dispersion of silicate layers...

  9. Enhanced performance of biodegradable poly(butylene succinate)/graphene oxide nanocomposites via in situ polymerization.

    Science.gov (United States)

    Wang, X W; Zhang, C-A; Wang, P L; Zhao, J; Zhang, W; Ji, J H; Hua, K; Zhou, J; Yang, X B; Li, X P

    2012-05-08

    Poly(butylene succinate) (PBS)/graphene oxide (GO) nanocomposites were facilely prepared via in situ polymerization. The properties of the nanocomposites were studied using FTIR, XRD, and (1)H NMR, and the state of dispersion of GO in the PBS matrix was examined by SEM. The crystallization and melting behavior of the PBS matrix in the presence of dispersed GO nanosheets have been studied by DSC and polarized optical microscopy. Through the mechnical testing machine and DMA, PBS/GO nanocomposites with 3% GO have shown a 43% increase in tensile strength and a 45% improvement in storage modulus. This high performance of the nanocomposites is mainly attributed to the high strength of graphene oxide combined with the strong interfacial interactions in the uniformly dispersed PBS/GO nanocomposites.

  10. Biocompatibility and characterization of polylactic acid/styrene-ethylene-butylene-styrene composites.

    Science.gov (United States)

    Tsou, Chi-Hui; Kao, Bo-Jyue; Yang, Ming-Chien; Suen, Maw-Cherng; Lee, Yi-Hsuan; Chen, Jui-Chin; Yao, Wei-Hua; Lin, Shang-Ming; Tsou, Chih-Yuan; Huang, Shu-Hsien; De Guzman, Manuel; Hung, Wei-Song

    2015-01-01

    Polylactic acid (PLA)/styrene-ethylene-butylene-styrene (SEBS) composites were prepared by melt blending. Differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WXRD) were used to characterize PLA and PLA/SEBS composites in terms of their melting behavior and crystallization. Curves from thermal gravimetric analysis (TGA) illustrated that thermostability increased with SEBS content. Further morphological analysis of PLA/SEBS composites revealed that SEBS molecules were not miscible with PLA molecules in PLA/SEBS composites. The tensile testing for PLA and PLA/SEBS composites showed that the elongation at the break was enhanced, but tensile strength decreased with increasing SEBS content. L929 fibroblast cells were chosen to assess the cytocompatibility; the cell growth of PLA was found to decrease with increasing SEBS content. This study proposes possible reasons for these properties of PLA/SEBS composites.

  11. Influence of Teflon substrate on crystallization and enzymatic degradation of polymorphic poly(butylene adipate)

    DEFF Research Database (Denmark)

    Ning, Zhenbo; Nielsen, Ronnie Bo Højstrup; Zhao, Lifen

    2014-01-01

    Oriented and non-oriented Teflon films, which were found to have the same crystalline structure, but different surface morphologies, were used to sandwich poly(butylene adipate) (PBA) films during isothermal crystallization. It was found that both the Teflon surface structure and the PBA...... polymorphic structure are the determining factors to induce epitaxial crystallization. The oriented Teflon film was able to induce epitaxial crystallization of PBA alpha crystal, while the non-oriented Teflon did not induce any epitaxial crystallization of PBA. Epitaxial crystallization did not occurred...... for PBA beta crystals between neither the oriented nor the non-oriented Teflon films. The enzymatic degradation rate of PBA films was not determined by the epitaxial crystallization, in fact it was still dependent on the polymorphic crystal structure of PBA. The morphological changes of PBA films after...

  12. Gamma radiation effects on random copolymers based on poly(butylene succinate) for packaging applications

    Science.gov (United States)

    Negrin, M.; Macerata, E.; Consolati, G.; Quasso, F.; Genovese, L.; Soccio, M.; Giola, M.; Lotti, N.; Munari, A.; Mariani, M.

    2018-01-01

    Within the context of new bioplastic materials, poly(butylene succinate) (PBS) and four novel poly(butylene/thiodiethylene succinate) random copolymers (PBS-PTDGS), in sheets as well as in films, were exposed to gamma radiation, in air and in water, and their behavior along with the effect on their biodegradability was investigated. The molecular weight data obtained from gel permeation chromatography indicate that the sensibility to radiation increases with the amount of sulfur-containing co-unit (TDGS). At 200 kGy the average molecular weight of PBS film halves, while for P(BS60TDGS40) the residual molecular weight is about 20%. The calculated intermolecular crosslink Gx and scissioning Gs yields confirmed that degradation is predominant over crosslink for all the aliphatic systems. As shown by thermal analyses, gamma radiation affects the thermal properties, leading to an increased crystallinity of the systems, remarkable for PBS, and lower decomposition temperatures. Variations of crystallinity with the increasing absorbed dose were confirmed also by PALS analyses. Water contact angle measurements revealed post-irradiation wettability alterations that could positively affect polymer biodegradability. In particular, when irradiated in water at 100 kGy PBS film exhibits a water contact angle decrease of about 17%, indicating an enhanced wettability. After degradation in compost, changes in the surface morphology were observed by means of SEM and sample weight losses were determined, at different extent, according to the irradiation environment. Interestingly, after 52 days in compost PBS films, both pristine and irradiated in air at 25 kGy, showed a residual weight of about 60%, while the ones irradiated in water at 25 kGy of about 44%. Experimental data confirmed that gamma irradiation could represent a viable treatment to enhance biodegradation in compost of PBS and PBS-based copolymers.

  13. Preparation and characterization of nanocomposite of maleated poly(butylene adipate-co-terephthalate) with organoclay.

    Science.gov (United States)

    Chen, Jung-Hung; Yang, Ming-Chien

    2015-01-01

    Nanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) with montmorillonite (MMT) nanoparticles were prepared via melt blending. Natural MMT was modified by either octadecylamine (ODA) or dihexylamine (DHA). Neat PBAT was grafted with maleic anhydride via melt grafting process. Intercalation of the organoclay in the PBAT matrix was studied by X-ray diffraction (XRD). From the results of transmission electron microscope (TEM), the dispersion of ODA-modified MMT in the PBAT matrix was more homogeneous than that of neat MMT. The addition of organoclay can increase the cooling crystallization temperature of PBAT, as observed by differential scanning calorimetry (DSC). Furthermore, the results of thermogravimetric analyzer (TGA) showed that the addition of ODA-modified MMT can improve the thermal stability of PBAT nanocomposites. The tensile strength was little affected, while the Young's modulus was increased with the addition of nanoclays. The grafting of PBAT with MA resulted in improved interaction between polymer matrix and the silicate layer due to the formation of chemical/physical bonds, thus the dispersion of organoclays was enhanced. By grafting PBAT with MA, the enzymatic biodegradation of the nanocomposite was increased, while the photodegradation of PBAT was little affected. Furthermore, the transmission of water vapor was reduced by the addition of organically modified MMT. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Starch/poly (butylene adipate-co-terephthalate/montmorillonite films produced by blow extrusion

    Directory of Open Access Journals (Sweden)

    Rodrigo A. L. Santos

    2014-07-01

    Full Text Available This study aims to prepare biodegradable films from cassava starch, poly (butylene adipate-co-terephthalate (PBAT, and montmorillonite (MMT using blow-extrusion process and analyze the effects of different types and concentrations of MMT on the microstructure, physicochemical, and mechanical properties of the resulting films. The films were produced by blending 30% of PBAT with glycerol (17.5%, starch (49.0-52.5%, and four different types of montmorillonite (Cloisite® Na+, 10A, 15A, and 30B at two different concentrations (1.75% and 3.5%. All the films prepared in this study showed an increase in the basal spacing of MMT layers. In particular, the films with 10A and 30B showed the highest increase in intercalation basal spacing, suggesting the formation of intercalated composites. The addition of nanoclays decreased the elongation of films. The addition of Cloisite® 10A resulted in films with the lowest WVP values and the highest stability to water adsorption under different RH conditions.

  15. Structure and properties of organically modified poly(butylene adipate-co-terephthalate) based nanocomposites

    Science.gov (United States)

    Rasyida, A.; Fukushima, K.; Yang, M.-C.

    2017-07-01

    Poly (butylene adipate-co-terephthalate (PBAT) nanocomposites were prepared by melt blending PBAT with 5 wt.% of modified or unmodified montmorillonites (MMT). The effect of the presence of organic modifiers in MMT on the morphological, crystalline, thermal, and mechanical properties of PBAT nanocomposites was evaluated. The dispersion and distribution of the clays were studied by using wide angle X-ray analysis (WAXS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis. Materials characterization techniques included: contact angle measurements, differential scanning calorimetry (DSC), thermogravimetry (TGA) and surface hardness analysis. As general results, nanocomposites exhibited different level of clay dispersion depending on the clay/organic modifier’s chemical affinity with the polymer. Contact angle measurements show increases in the hydrophobicity level of PBAT based CLO30B, this could depict its high potential for packaging applications. In addition, Thermal analysis showed that clays partially hindered kinetics and extent of PBAT crystallization on cooling. In general, thermal properties of PBAT were improved by addition of clays, for a barrier effect of the nanoparticle towards polymer decomposition products ablation. In parallel, addition of clays led to enhancements in polymer hardness. These properties were found to be apparently influenced by clay dispersion level and chemical compatibility between the organic modifier and polymer matrix.

  16. The tensile strength test of thermoplastic materials based on poly(butylene terephtalate

    Directory of Open Access Journals (Sweden)

    Rzepecka Anna

    2017-01-01

    Full Text Available Thermoplastic composites go toward making an increasingly greater percentage of all manufacturing polymer composites. They have a lot of beneficial properties and their manufacturing using injecting and extrusion methods is a very easy and cheap process. Their properties significantly overtake the properties of traditional materials and it is the reason for their use. Scientists are continuously carrying out research to find new applications of composites materials in new industries, not only in the automotive or aircraft industry. When thermoplastic composites are manufactured a very important factor is the appropriate accommodation of tensile strength to their predestination. Scientists need to know the behaviour of these materials during the impact of different forces, and the factors of working in normal conditions too. The main aim of this article was macroscopic and microscopic analysis of the structure of thermoplastic composites after static tensile strength test. Materials which were analysed were thermoplastic materials which have poly(butylene terephthalate – PBT matrix reinforced with different content glass fibres – from 10% for 30%. In addition, research showed the necessary force to receive fracture and set their distinguishing characteristic down.

  17. Ethylene oxide-block-butylene oxide copolymer uptake by silicone hydrogel contact lens materials

    Energy Technology Data Exchange (ETDEWEB)

    Huo, Yuchen [Department of Materials Science and Engineering, University of Florida, Rhines Hall 100, Gainesville, FL 32611 (United States); Ketelson, Howard [Alcon Inc., Research and Development, Vision Care, 6201 South Freeway, Fort Worth, TX 76134 (United States); Perry, Scott S., E-mail: ssp@mse.ufl.edu [Department of Materials Science and Engineering, University of Florida, Rhines Hall 100, Gainesville, FL 32611 (United States)

    2013-05-15

    Four major types of silicone hydrogel contact lens material have been investigated following treatments in aqueous solutions containing poly(ethylene oxide) and poly(butylenes oxide) block copolymer (EO–BO). The extent of lens surface modification by EO–BO and the degree of bulk uptake were studied using X-ray photoelectron spectroscopy (XPS) and ultra-performance liquid chromatography (UPLC), respectively. The experimental results suggest that different interaction models exist for the lenses, highlighting the influence of both surface and bulk composition, which greatly differs between the lenses examined. Specifically, lenses with hydrophilic surface treatments, i.e., PureVision{sup ®} (balafilcon A) and O{sub 2}OPTIX (lotrafilcon B), demonstrated strong evidence of preferential surface adsorption within the near-surface region. In comparison, surface adsorption on ACUVUE{sup ®} Oasys{sup ®} (senofilcon A) and Biofinity{sup ®} (comfilcon A) was limited. As for bulk absorption, the amount of EO–BO uptake was the greatest for balafilcon A and comfilcon A, and least for lotrafilcon B. These findings confirm the presence of molecular concentration gradients within the silicone hydrogel lenses following exposure to EO–BO solutions, with the nature of such concentration gradients found to be lens-specific. Together, the results suggest opportunities for compositional modifications of lenses for improved performance via solution treatments containing surface-active agents.

  18. Ethylene oxide-block-butylene oxide copolymer uptake by silicone hydrogel contact lens materials

    Science.gov (United States)

    Huo, Yuchen; Ketelson, Howard; Perry, Scott S.

    2013-05-01

    Four major types of silicone hydrogel contact lens material have been investigated following treatments in aqueous solutions containing poly(ethylene oxide) and poly(butylenes oxide) block copolymer (EO-BO). The extent of lens surface modification by EO-BO and the degree of bulk uptake were studied using X-ray photoelectron spectroscopy (XPS) and ultra-performance liquid chromatography (UPLC), respectively. The experimental results suggest that different interaction models exist for the lenses, highlighting the influence of both surface and bulk composition, which greatly differs between the lenses examined. Specifically, lenses with hydrophilic surface treatments, i.e., PureVision® (balafilcon A) and O2OPTIX (lotrafilcon B), demonstrated strong evidence of preferential surface adsorption within the near-surface region. In comparison, surface adsorption on ACUVUE® Oasys® (senofilcon A) and Biofinity® (comfilcon A) was limited. As for bulk absorption, the amount of EO-BO uptake was the greatest for balafilcon A and comfilcon A, and least for lotrafilcon B. These findings confirm the presence of molecular concentration gradients within the silicone hydrogel lenses following exposure to EO-BO solutions, with the nature of such concentration gradients found to be lens-specific. Together, the results suggest opportunities for compositional modifications of lenses for improved performance via solution treatments containing surface-active agents.

  19. Effect of Rubberwood Content on Biodegradability of Poly(butylene succinate Biocomposites

    Directory of Open Access Journals (Sweden)

    Hemhong Anankaphong

    2015-01-01

    Full Text Available Poly(butylene succinate (PBS biocomposites incorporated with rubberwood powder (RWP were fabricated with various RWP weight fractions (i.e., 0 to 40% wt by injection moulding process. The soil burial test was employed to examine the biodegradability of such biocomposites under outdoor environment for 60 days. The physical appearance, percentage weight loss, chemical structure, and mechanical properties before and after the soil burial test were determined. Apparent changes in physical appearance of the biocomposites from optical micrographs were detected in terms of surface morphology and colour. The percentage of crystallinity of PBS/RWP biocomposites was studied by the X-ray diffraction (XRD technique, and the XRD pattern revealed a decrease in percentage of crystallinity due to enhancing RWP weight fractions. This may be attributed to a presence of rubberwood powders providing more disordered molecular chain arrangement of PBS matrix and also an agglomeration of the rubberwood powder content at greater concentration as seen in SEM micrographs. With increasing RWP weight fractions and burial time, the results exhibited a considerable change in chemical structure (essentially ester linkage due to biodegradation mechanism of PBS, relatively greater percentage weight loss, and a substantial decrease in flexural properties. Consequently, the results indicate that incorporating RWP enhances biodegradability of PBS/RWP biocomposites; that is, the biodegradation rate of biocomposites increases with increasing RWP weight fractions and burial time.

  20. Thermal and Mechanical Properties of Poly(butylene succinate Films Reinforced with Silica

    Directory of Open Access Journals (Sweden)

    Sangviroon Nanthaporn

    2015-01-01

    Full Text Available In recent year, bioplastics have become more popular resulting from the growing concerns on environmental issues and the rising fossil fuel price. However, their applications were limited by its mechanical and thermal properties. The aim of this research is thus to improve mechanical and thermal properties of PBS bioplastic films by reinforcing with silica. Due to the poor interfacial interaction between the PBS matrix and silica, glycidyl methacrylate grafted poly(butylene succinate (PBS-g-GMA was used as a compatibilizer in order to improve the interaction between bioplastic films and filler. PBS-g-GMA was prepared in a twin-screw extruder and analyzed by the FTIR spectrometer. PBS and silica were then mixed in a twin-screw extruder and processed into films by a chill-roll cast extruder. The effects of silica loading on thermal and mechanical properties of the prepared bioplastic films were investigated. It was found that the mechanical properties of PBS/silica composite films were improved when 1%wt of silica was added. However, the mechanical properties decreased with increasing silica loading due to the agglomeration of silica particles. The results also show that the silica/PBS films with PBS-g-GMA possessed improved mechanical properties over the films without the compatibilizer.

  1. Analysis of Gas Permeability Characteristics of Poly(Lactic Acid/Poly(Butylene Succinate Nanocomposites

    Directory of Open Access Journals (Sweden)

    Amita Bhatia

    2012-01-01

    Full Text Available Gas permeability and morphological properties of nanocomposites prepared by the mixing of poly(lactic acid (PLA, poly(butylene succinate (PBS, and clay was investigated. While the composition of PLA and PBS polymers was fixed as 80% and 20% by weight, respectively, for all the nanocomposites, clay contents varied from 1 to 10 wt%. From the morphological studies using both wide angle X-ray diffraction and transmission electron microscopy, the nanocomposite having 1 wt% of clay was considered to have a mixed morphology of intercalated and delaminated structure, while some clusters or agglomerated particles were detected for nanocomposites having 3 and more than 3 wt% of clay content. However, the average particle size of the dispersed PBS phase was reduced significantly from 7 μm to 30–40 nm with the addition of clay in the blend. The oxygen barrier property was improved significantly as compared to the water vapor. A model based on gas barrier property was used for the validation of the oxygen relative permeabilities of PLA/PBS/clay nanocomposites. PLA/PBS/clay nanocomposites validated the Bharadwaj model up to 3 wt% of clay contents only, while for nanocomposites of higher clay contents the Bharadwaj model was invalid due to the clusters and agglomerates formed.

  2. Study of the mechanical properties of Acrylonitrile Butadiene Styrene - High Impact Polystyrene blends with Styrene Ethylene Butylene Styrene

    OpenAIRE

    PEYDRO Miguel Angel; JUAREZ David; Sanchez-Caballero, Samuel; PARRES Francisco

    2013-01-01

    A binary blend Acrylonitrile Butadiene Styrene ¿ High Impact Polystyrene (ABS-HIPS 50% wt) was prepared on a twin-screw extruder at 190-210 oC. The different mechanical properties were then analyzed using tensile strength and impact tests. The analysis of mechanical properties showed a decrease in elongation at break and impact strength. On the other hand, we have prepared ternary blends of ABS-HIPS- Styrene Ethylene Butylene Styrene (SEBS), varying the percentage of SEBS from 10 to 30 %wt us...

  3. Crystallization behavior of partially miscible biodegradable poly(butylene succinate)/poly(ethylene succinate) blends

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi-Song [Center for Degradable and Flame-Retardant Polymeric Materials (ERCPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Zeng, Jian-Bing, E-mail: zengjianbing@scu.edu.cn [Center for Degradable and Flame-Retardant Polymeric Materials (ERCPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Li, Shao-Long [Center for Degradable and Flame-Retardant Polymeric Materials (ERCPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Wang, Yu-Zhong, E-mail: yzwang@scu.edu.cn [Center for Degradable and Flame-Retardant Polymeric Materials (ERCPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China)

    2012-02-10

    Graphical abstract: Crystallization rate of PBS in the blends decreased first and then increased with increase in PES content, and that of PES increased steadily with increase in PBS content. The rich component formed a continuous phase and the other formed a dispersed phase of the blend. Crystal structures of PBS and PES were almost unchanged after blending with each other. Highlights: Black-Right-Pointing-Pointer PBS/PES blend systems are partially miscible. Black-Right-Pointing-Pointer Blending did not change the crystallization mechanisms of PBS and PES not affects the crystallization rates. Black-Right-Pointing-Pointer The rich component formed the continuous phase while the poor component formed the dispersed phase of the blends. Black-Right-Pointing-Pointer Crystal structures of PBS and PES were almost unchanged after blending with each other. - Abstract: Biodegradable blend of poly(butylene succinate) (PBS) and poly(ethylene succinate) (PES) was prepared by solution blending and casting method with chloroform as a mutual solvent. Miscibility of the blends was investigated by differential scanning calorimetry (DSC). The results indicated that PBS and PES were partially miscible. Crystallization kinetics, crystalline morphology and crystal structure of the blends were studied by DSC, polarized optical microscope (POM), and wide-angle X-ray diffraction (WAXD), respectively. Nonisothermal and isothermal crystallization kinetics suggested that the crystallizability of PBS in the blends decreased first and then increased with increase in PES content, and that of PES increased steadily with increase in PBS content. POM observation illustrated that the rich component formed a continuous phase and the other formed a dispersed phase. The results of WAXD indicated that the crystal structures of PBS and PES were almost unchanged before and after blending, since the positions of characteristic diffraction peaks of both components remain almost unchanged.

  4. Preparation and characterization of nanocomposite of maleated poly(butylene adipate-co-terephthalate) with organoclay

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jung-Hung [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Yang, Ming-Chien, E-mail: myang@mail.ntust.edu.tw [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2015-01-01

    Nanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) with montmorillonite (MMT) nanoparticles were prepared via melt blending. Natural MMT was modified by either octadecylamine (ODA) or dihexylamine (DHA). Neat PBAT was grafted with maleic anhydride via melt grafting process. Intercalation of the organoclay in the PBAT matrix was studied by X-ray diffraction (XRD). From the results of transmission electron microscope (TEM), the dispersion of ODA-modified MMT in the PBAT matrix was more homogeneous than that of neat MMT. The addition of organoclay can increase the cooling crystallization temperature of PBAT, as observed by differential scanning calorimetry (DSC). Furthermore, the results of thermogravimetric analyzer (TGA) showed that the addition of ODA-modified MMT can improve the thermal stability of PBAT nanocomposites. The tensile strength was little affected, while the Young's modulus was increased with the addition of nanoclays. The grafting of PBAT with MA resulted in improved interaction between polymer matrix and the silicate layer due to the formation of chemical/physical bonds, thus the dispersion of organoclays was enhanced. By grafting PBAT with MA, the enzymatic biodegradation of the nanocomposite was increased, while the photodegradation of PBAT was little affected. Furthermore, the transmission of water vapor was reduced by the addition of organically modified MMT. - Highlights: • Nanocomposites of PBAT and clay nanoparticles were prepared via melting blending. • Maleated PBAT/organoclays exhibited higher Young's moduli than neat PBAT/neat MMT. • The enzymatic degradation of PBAT composites was improved by maleation. • Maleation caused little effect on the photodegradation of PBAT. • Organoclays retarded the permeation of water vapor through PBAT composites.

  5. Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

    Directory of Open Access Journals (Sweden)

    Jutakan Boonmee

    2016-01-01

    Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

  6. Nanoencapsulation of Nimodipine in Novel Biocompatible Poly(propylene-co-butylene succinate Aliphatic Copolyesters for Sustained Release

    Directory of Open Access Journals (Sweden)

    Sofia Papadimitriou

    2009-01-01

    Full Text Available Biocompatible poly(propylene-co-butylene succinate (PPBSu copolyesters, containing up to 50 mol% butylene succinate units, were synthesized by the two-stage melt polycondensation method (esterification and polycondensation. The copolymers were fully characterized and biocompatibility studies were also performed. They were proved to be biocompatible and they were used as polymer matrices for the preparation of drug loaded nanoparticles. Nimodipine was selected as a model hydrophobic poorly water soluble drug. From the results obtained by dynamic light scattering (DLS and scanning electron microscopy (SEM, drug loaded copolymer nanoparticles were found to exhibit a spherical shape and their mean diameter appeared in the range of 180–200 nm. Fourier Transformation-Infrared Spectroscopy (FTIR spectra indicated that no chemical interaction between the drug and the matrix could be justified, while Wide-Angle X-Ray Diffraction (WAXD patterns proved a low degree of crystallinity of Nimodipine in the nanoparticles. The release behavior of the model drug from nanoparticles was also investigated in order to identify modifications and find out any possible correlation between the chemical composition of the polymer matrix and the drug release rates.

  7. Polystyrene/TiO2 composite electrospun fibers as fillers for poly(butylene succinate-co-adipate): Structure, morphology and properties

    NARCIS (Netherlands)

    Neppalli, Ramesh; Causin, Valerio; Benetti, Edmondo Maria; Ray, Suprakas Sinha; Esposito, Antonella; Wanjale, Santosh; Birajdar, Mallinath; Saiter, Jean-Marc; Marigo, Antonio

    2014-01-01

    In this work, composite polystyrene/titanium dioxide (PS/TiO2) electrospun fibers were used as a reinforcement for a poly(butylene succinate-co-adipate) (PBSA) matrix. The structure, morphology, mechanical properties and degradation behavior of such materials were investigated, finding that, as a

  8. Alternating polyesteramides based on 1,4-butylene terephthalamide: 3. alternating polyesteramides based on mixtures of, linear diols (4NTm,p)

    NARCIS (Netherlands)

    Serrano, P.J.M.; Serrano, P.J.M.; van de Werff, B.A.; van der Werff, B.A.; Gaymans, R.J.

    1998-01-01

    Strictly alternating polyesteramides consisting of 1,4-butylene terephthalamide diester and mixtures of aliphatic diols have been synthesised in the melt in the presence of a titanium catalyst. To increase the molecular weight a solid state post condensation was applied. The composition was

  9. Poly(ethylene oxide)/poly(butylene terephthalate) segmented block copolymers: the effect of copolymer composition on physical properties and degradation behavior

    NARCIS (Netherlands)

    Deschamps, A.A.; Grijpma, Dirk W.; Feijen, Jan

    2001-01-01

    In this study, the influence of copolymer composition on the physical properties and the degradation behavior of thermoplastic elastomers based on poly(ethylene oxide) (PEO) and poly(butylene terephthalate) (PBT) segments is investigated. These materials are intended to be used in medical

  10. Effect of nanoclay on the nonisothermal crystallization of poly(propylene) and its blend with poly[(butylene succinate)-co-adipate

    CSIR Research Space (South Africa)

    Bandyopadhyay, J

    2012-05-01

    Full Text Available The non-isothermal crystallization behaviour and kinetics of neat poly(propylene)(PP), PP/poly[(butylene succinate)-co-adipate] (PP/PBSA) blend and its composite with nanoclay was studied by differential scanning calorimetry at six different cooling...

  11. Effect of planar extension on the structure and mechanical properties of polystyrene-poly(ethylene-¤co¤-butylene)-polystyrene triblock copolymers

    DEFF Research Database (Denmark)

    Daniel, C.; Hamley, I.W.; Mortensen, K.

    2000-01-01

    Two thermoplastic poly(styrene)-poly(ethylene-co-butylene) -poly(styrene) triblock copolymers containing either spherical or cylindrical poly(styrene) microdomains were pre-oriented through extensional flow. Small angle neutron scattering (SANS) measurements revealed that the pre-oriented triblock...

  12. Polystyrene/TiO2 composite electrospun fibers as fillers for poly(butylene succinate-co-adipate): Structure, morphology and properties

    CSIR Research Space (South Africa)

    Neppalli, R

    2014-01-01

    Full Text Available In this work, composite polystyrene/titanium dioxide (PS/TiO(sub2)) electrospun fibers were used as a reinforcement for a poly(butylene succinate-co-adipate) (PBSA) matrix. The structure, morphology, mechanical properties and degradation behavior...

  13. Processing and characterization of recycled poly(ethylene terephthalate) blends with chain extenders, thermoplastic elastomer, and/or poly(butylene adipate-co-terephthalate)

    Science.gov (United States)

    Yottha Srithep; Alireza Javadi; Srikanth Pilla; Lih-Sheng Turng; Shaoqin Gong; Craig Clemons; Jun Peng

    2011-01-01

    Poly(ethylene terephthalate) (PET) resin is one of the most widely used thermoplastics, especially in packaging. Because thermal and hydrolytic degradations, recycled PET (RPET) exhibits poor mechanical properties and lacks moldability. The effects of adding elastomeric modifiers, chain extenders (CE), and poly(butylenes adipate-co-terephthalate), PBAT, as a toughener...

  14. Effects of chemical versus enzymatic processing of kenaf fibers on poly(hydroxybutyrate-co-valerate)/poly(butylene adipate-co-terephthalate) composite properties

    Science.gov (United States)

    The effect of fiber retting on crystallization and mechanical performance was investigated. A poly(hydroxybutyrate-co-valerate) (PHBV) and poly(butylene adipate-co-terephthalate) (PBAT) blend in a 80/20 ratio was modified using 5% by weight kenaf (Hibiscus cannabinus L.) fiber. Fibers were retted us...

  15. Morphology, melting behavior, and non-isothermal crystallization of poly(butylene terephthalate)/poly(ethylene-co-methacrylic acid) blends

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.-W. [Department of Styling and Cosmetology, Tainan University of Technology, 529 Chung Cheng Rd., Yung Kang City 710, Taiwan (China)], E-mail: jw.huang@msa.hinet.net; Wen, Y.-L. [Department of Nursing, Meiho Institute of Technology, 23 Ping Kuang Rd., Neipu Hsiang, Pingtung 912, Taiwan (China); Department of Resources Engineering, National Cheng Kung University, No. 1, University Rd., Tainan City 701, Taiwan (China); Kang, C.-C. [R and D Center, Hi-End Polymer Film Co., Ltd. 15-1 Sin Jhong Rd., Sin Ying City 730, Taiwan (China); Yeh, M.-Y. [Department of Chemistry, National Cheng Kung University, No. 1, University Rd., Tainan City 701, Taiwan (China); Sustainable Environment Research Centre, National Cheng Kung University, Taiwan (China); Wen, S.-B. [Department of Nursing, Meiho Institute of Technology, 23 Ping Kuang Rd., Neipu Hsiang, Pingtung 912, Taiwan (China); Department of Resources Engineering, National Cheng Kung University, No. 1, University Rd., Tainan City 701, Taiwan (China)

    2007-12-15

    The morphology, melting behavior, and non-isothermal crystallization of poly(butylene terephthalate) (PBT) and poly(ethylene-co-methacrylic acid) (PEMA) blends were studied with scanning electron microscopy, X-ray diffraction and differential scanning calorimetry (DSC). PEMA forms immiscible, yet compatible, blends with PBT. Subsequent DSC scans on melt-crystallized samples exhibited two melting endotherms (T{sub mI} and T{sub mII}). The presence of PEMA would facilitate the recrystallization during heating scan and retard PBT molecular chains to form a perfect crystal in cooling crystallization. The dispersion phases of molten PEMA acts as nucleating agents to enhance the crystallization rate of PBT. The solidified PBT could act as nucleating agents to enhance the crystallization of PEMA, but also retard the molecular mobility to reduce crystallization rate. The U* and K{sub g} of Hoffman-Lauritzen theory were also determined by Vyazovkin's methods to support the interpretation.

  16. Delivery of paclitaxel using nanoparticles composed of poly(ethylene oxide)-b-poly(butylene oxide) (PEO-PBO).

    Science.gov (United States)

    Wang, Lijiang; Yao, Ju; Zhang, Xiaomin; Zhang, Yingxin; Xu, Chang; Lee, Robert J; Yu, Gary; Yu, Bo; Teng, Lesheng

    2017-11-07

    An amphiphilic block copolymer poly(ethylene oxide)-b-poly(butylene oxide) (PEO-PBO) was evaluated as a carrier for therapeutic delivery of paclitaxel (PTX). PEO-PBO and PTX form nanoparticles (NPs) by self-assembly upon hydration. The size of these NPs was about 92.71nm and the zeta potential was -5.06mV, which met the requirements for passive tumor targeting through the enhanced permeability and retention effect. Compared with a commonly used block copolymer poly(ethylene glycol)-b-poly-D,L-(lactic acid) (PEG-PDLLA), PEO-PBO forms nanoparticles with superior pharmacokinetic, biodistribution, and tumor inhibitory properties. Meanwhile, results of hemolysis study and CMC determination showed that PEO-PBO had better biocompatibility and stability than PEG-PDLLA. These data suggest that PEO-PBO has potential for application in drug delivery and warrant further evaluation. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Non-isothermal crystallization kinetics and characterization of biodegradable poly(butylene succinate-co-neopentyl glycol succinate) copolyesters.

    Science.gov (United States)

    Xie, Wen-Jie; Zhou, Xiao-Ming

    2015-01-01

    Both biodegradable aliphatic neat poly(butylene succinate) (PBS) and poly(butylene succinate-co-neopentyl glycol succinate) (P(BS-co-NPGS)) copolyesters with different 1,4-butanediol/neopentyl glycol ratios were synthesized through a two-step process of transesterification and polycondensation using stannous chloride and 4-Methylbenzenesulfonic acid as the co-catalysts. The structure, non-isothermal crystallization behavior, crystalline morphology and crystal structure of neat PBS and P(BS-co-NPGS) copolyesters were characterized by (1)H NMR, differential scanning calorimetry (DSC), polarized optical microscope (POM) and wide angle X-ray diffraction (WAXD), respectively. The Avrami equation modified by Jeziorny and Mo's method was employed to describe the non-isothermal crystallization kinetics of the neat PBS and its copolyesters. The modified Avrami equation could adequately describe the primary stage of non-isothermal crystallization kinetics of the neat PBS and its copolyesters. Mo's method provided a fairly satisfactory description of the non-isothermal crystallization of neat PBS and its copolyesters. Interestingly, the values of 1/t1/2, Zc and F(T) obtained by the modified Avrami equation and Mo's method analysis indicated that the crystallization rate increased first and then decreased with an increase of NPGS content compared that of neat PBS, whereas the crystallization mechanism almost kept unchanged. The results of tensile testing showed that the ductility of PBS was largely improved by incorporating NPGS units. The elongation at break increased remarkably with increasing NPGS content. In particular, the sample with 20% NPGS content showed around 548% elongation at break. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Ionic liquids as surfactants for layered double hydroxide fillers: effect on the final properties of poly(butylene adipate-co-terephthalate)

    Czech Academy of Sciences Publication Activity Database

    Livi, S.; Lins, L. C.; Peter, Jakub; Beneš, Hynek; Kredatusová, Jana; Donato, R. K.; Pruvost, S.

    2017-01-01

    Roč. 7, č. 10 (2017), s. 1-16, č. článku 297. ISSN 2079-4991 R&D Projects: GA ČR(CZ) GA17-08273S Institutional support: RVO:61389013 Keywords : ionic liquids * poly(butylene adipate-co-terephthalate) * layered double hydroxide Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.553, year: 2016

  19. Production and characterization of novel starch and poly(butylene adipate-co-terephthalate)-based materials and their applications

    Science.gov (United States)

    Stagner, Jacqueline Ann

    This work focuses on the production and characterization of blends of maleated thermoplastic starch (MTPS) and poly(butylenes adipate-co-terephthalate) and their application for use as thermoformed objects, films, and foams. First, by the production and characterization of maleated thermoplastic starch (MTPS) synthesized by reactive extrusion in a twin-screw extruder, a better understanding of MTPS was gained. This reactive thermoplastic starch was prepared with glycerol as the plasticizer, maleic anhydride (MA), and free-radical initiator, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (Luperox 101). Dynamic light scattering (DLS), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), soxhlet extraction in acetone, and environmental scanning electron microscopy (ESEM) were performed to determine the effect of maleation, extrusion temperature, initiator concentration, and maleic anhydride concentration on the resulting MTPS. Next, maleated thermoplastic starch (MTPS) and thermoplastic starch (TPS) were reactively blended in a twin-screw extruder with a biodegradable polyester, poly(butylene adipate-co-terephthalate) (PBAT). The blends were extruded to produce thermoformable sheets. The mechanical properties of the sheets were characterized by tensile and puncture tests. Proof of grafting was determined by soxhlet extraction in dichloromethane and FTIR analysis. Observations of the thermal properties were made using DSC, while the surface of the sheets was imaged using ESEM. Blends of MTPS and PBAT were also extruded to produce films. Mechanical testing (tensile and puncture tests) and barrier performance testing (carbon dioxide, oxygen, and water vapor permeability) were performed on the films. Transmission electron microscopy (TEM) was used to image the blends and to view the dispersion of the various phases. Finally, blends of MTPS and PBAT were extruded with an endothermic chemical blowing agent to produce foams. The foams were

  20. Computational Modeling of Polystyrene-b-(ethylene-co-butylene)-b-styrene and Mineral Oil Gels and Nanocomposites

    Science.gov (United States)

    Chantawansri, T. L.; Berg, M.; Mrozek, R.; Stokes, K.; Henz, B.; Chung, P.; Beyer, F.; Lenhart, J.; Andzelm, J. W.

    2010-03-01

    There has been substantial interest in thermoplastic elastomer (TPE) gels composed of poly(styrene-b-(ethylene-co-butylene)-b-styrene)(SEBS) and hydrocarbon oils. Although the effects of adding nanoparticles on TPE gels is relatively unexplored, research in polymer nanocomposites have shown that the addition of nanoparticles enhanced physical properties. The microstructure of such a system is dependent on a variety of parameters such as block copolymer and nanoparticle concentrations, temperature, nanoparticle size, and nanoparticle interaction; thus to perform an extensive study of phase space, mesoscale modeling should be used in conjunction with the experimentation. To complement our experimental system, mesoscale modeling of this TPE gel and the corresponding nanocomposite are preformed using dynamic density functional theory and self consistent field theory through Materials Studio, where morphology of the system is studied as a function of various parameters and conditions. The validity of the computational methods has been confirmed for a number of experimental results, and subsequently has been used to explore a larger design space than is accessible solely through experimental methods.

  1. Fabrication of Chitin/Poly(butylene succinate/Chondroitin Sulfate Nanoparticles Ternary Composite Hydrogel Scaffold for Skin Tissue Engineering

    Directory of Open Access Journals (Sweden)

    S. Deepthi

    2014-12-01

    Full Text Available Skin loss is one of the oldest and still not totally resolved problems in the medical field. Since spontaneous healing of the dermal defects would not occur, the regeneration of full thickness of skin requires skin substitutes. Tissue engineering constructs would provide a three dimensional matrix for the reconstruction of skin tissue and the repair of damage. The aim of the present work is to develop a chitin based scaffold, by blending it with poly(butylene succinate (PBS, an aliphatic, biodegradable and biocompatible synthetic polymer with excellent mechanical properties. The presence of chondroitin sulfate nanoparticles (CSnp in the scaffold would favor cell adhesion. A chitin/PBS/CSnp composite hydrogel scaffold was developed and characterized by SEM (Scanning Electron Microscope, FTIR (Fourier Transform Infrared Spectroscopy, and swelling ratio of scaffolds were analyzed. The scaffolds were evaluated for the suitability for skin tissue engineering application by cytotoxicity, cell attachment, and cell proliferation studies using human dermal fibroblasts (HDF. The cytotoxicity and cell proliferation studies using HDF confirm the suitability of the scaffold for skin regeneration. In short, these results show promising applicability of the developed chitin/PBS/CSnps ternary composite hydrogel scaffolds for skin tissue regeneration.

  2. Effect of dissolved oxygen on heterotrophic denitrification using poly(butylene succinate) as the carbon source and biofilm carrier.

    Science.gov (United States)

    Luo, Guozhi; Li, Li; Liu, Qian; Xu, Guimei; Tan, Hongxin

    2014-11-01

    The effect of dissolved oxygen (DO) on heterotrophic denitrification using poly(butylene succinate) as the carbon source and biofilm carrier was evaluated in a lab-scale experiment. Aerated, low-oxygen, and anoxic treatment groups were set up, which had average DO concentrations of 5.2±1.0, 1.4±1.2, and 0.5±0.3 mg L(-1), respectively. The NO3(-)-N and total nitrogen (TN) removal rates in the aerated group (37.44±0.24 and 36.24±0.48 g m(-3) d(-1), respectively) were higher than those in the other two groups. There was no significant difference between the low-oxygen and anoxic groups for the NO3(-)-N or TN removal rate. Accumulation of NO2(-)-N reached 5.0 mg L(-1) in the aerated group; no nitrite accumulation was found in the other two treatment groups. Bacterial communities of the low-oxygen and anoxic groups showed high similarity and were significantly different from those of the aerated group. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Biological denitrification using poly(butylene succinate) as carbon source and biofilm carrier for recirculating aquaculture system effluent treatment.

    Science.gov (United States)

    Zhu, Song-Ming; Deng, Ya-Le; Ruan, Yun-Jie; Guo, Xi-Shan; Shi, Ming-Ming; Shen, Jia-Zheng

    2015-09-01

    Nitrate removal is essential for the sustainable operation of recirculating aquaculture system (RAS). This study evaluated the heterotrophic denitrification using poly(butylene succinate) as carbon source and biofilm carrier for RAS wastewater treatment. The effect of varied operational conditions (influent type, salinity and nitrate loading) on reactor performance and microbial community was investigated. The high denitrification rates of 0.53 ± 0.19 kg NO3(-)-N m(-3) d(-1) (salinity, 0‰) and 0.66 ± 0.12 kg NO3(-)-Nm(-3) d(-1) (salinity, 25‰) were achieved, and nitrite concentration was maintained below 1mg/L. In addition, the existence of salinity exhibited more stable nitrate removal efficiency, but caused adverse effects such as excessive effluent dissolved organic carbon (DOC) and dissimilation nitrate reduce to ammonia (DNRA) activity. The degradation of PBS was further confirmed by SEM and FTIR analysis. Illumina sequencing revealed the abundance and species changes of functional denitrification and degradation microflora which might be the primary cause of varied reactor performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Poly(butylene 2,5-thiophenedicarboxylate: An Added Value to the Class of High Gas Barrier Biopolyesters

    Directory of Open Access Journals (Sweden)

    Giulia Guidotti

    2018-02-01

    Full Text Available Many efforts are currently devoted to the design and development of high performance bioplastics to replace traditional fossil-based polymers. In response, this contribution presents a new biobased aromatic polyester, i.e., poly(butylene 2,5-thiophenedicarboxylate (PBTF. Here, PBTF is characterized from the molecular, thermo-mechanical and structural point of view. Gas permeability is evaluated at different temperatures, in the range below and above glass transition, providing a full insight into the performances of this material under different operating conditions, and demonstrating the superior gas barrier behavior of PBTF with respect to other polyesters, such as PEF and PET. The combination of calorimetric and diffractometric studies allows for a deep understanding of the structure of PBTF, revealing the presence of a not-induced 2D-ordered phase (meso-phase, responsible for its outstanding gas permeability behavior. The simple synthetic strategy adopted, the exceptional barrier properties, combined with the interesting mechanical characteristics of PBTF open up new scenarios in the world of green and sustainable packaging materials.

  5. Toughening of biodegradable polylactide/poly(butylene succinate-co-adipate) blends via in situ reactive compatibilization.

    Science.gov (United States)

    Ojijo, Vincent; Ray, Suprakas Sinha; Sadiku, Rotimi

    2013-05-22

    Polylactide and poly(butylene succinate-co-adipate) (PLA/PBSA) were melt-blended in the presence of triphenyl phosphite (TPP). An increase in the torque during melt mixing was used to monitor the changes in viscosity as compatibilization of the blends occurred. Scanning electron micrographs showed not only a reduction in the dispersed-phase size with increased TPP content but also fibrillated links between the PLA and PBSA phases, signifying compatibilization. Moreover, optimization of parameters such as the mixing sequence and time, TPP content, and PBSA concentration revealed that blends containing 30 and 10 wt % PBSA and 2 wt % TPP, which were processed for 30 min, were optimal in terms of thermomechanical properties. The impact strength increased from 6 kJ/m(2) for PLA to 11 and 16 kJ/m(2) for blends containing 30 and 10 wt % PBSA, respectively, whereas the elongation-at-break increased from 6% for PLA to 20 and 37% for blends containing 30 and 10 wt % PBSA, respectively. Upon compatibilization, the failure mode shifted from the brittle fracture of PLA to ductile deformation, effected by the debonding between the two phases. With improved phase adhesion, compatibilized blends not only were toughened but also did not significantly lose tensile strength and thermal stability.

  6. Hybrids of HNBR and in situ polymerizable cyclic butylene terephthalate (CBT oligomers: properties and dry sliding behavior

    Directory of Open Access Journals (Sweden)

    2008-07-01

    Full Text Available A peroxide curable hydrogenated nitrile rubber (HNBR was modified by cyclic butylene terephthalate oligomer (CBT, added in 100 parts per hundred rubber (phr. CBT polymerization was expected to occur simultaneously with that of the curing of the HNBR rubber (T = 190°C, t = 25 min. Differential scanning calorimetry (DSC indicated that only a minor part of CBT has been polymerized (pCBT in the hybrid. Dynamic mechanical thermal analysis (DMTA revealed that HNBR formed the continuous whereas (pCBT the dispersed phase. Mechanical properties (hardness, tensile modulus, ultimate tensile strength and strain, tear strength of the HNBR and HNBR/CBT were determined and collated. Tribological properties were investigated with pin(steel-onplate(rubber (POP, with roller(steel-on-plate (rubber (ROP, with oscillating steel cylinder on rubber plate (Fretting test configurations. Coefficient of friction (COF and specific wear rate of the HNBR-based systems were determined. It was found that the resistance to wear increases with CBT hybridization. On the other hand, COF did not change much with CBT content. The friction and wear characteristics strongly depended on the test configurations. The worn surface of the HNBR systems was inspected in scanning electron microscope (SEM to conclude the typical wear mechanisms. SEM investigation showed that the CBT was predominantly recrystallized from its molten state under the curing conditions set. The well developed prism- and platy-like, micron-scaled CBT crystals were made responsible for the reinforcing effect observed.

  7. Phase Morphology and Mechanical Properties of Cyclic Butylene Terephthalate Oligomer-Containing Rubbers: Effect of Mixing Temperature

    Directory of Open Access Journals (Sweden)

    István Zoltán Halász

    2016-08-01

    Full Text Available In this work, the effect of mixing temperature (Tmix on the mechanical, rheological, and morphological properties of rubber/cyclic butylene terephthalate (CBT oligomer compounds was studied. Apolar (styrene butadiene rubber, SBR and polar (acrylonitrile butadiene rubber, NBR rubbers were modified by CBT (20 phr for reinforcement and viscosity reduction. The mechanical properties were determined in tensile, tear, and dynamical mechanical analysis (DMTA tests. The CBT-caused viscosity changes were assessed by parallel-plate rheometry. The morphology was studied by scanning electron microscopy (SEM. CBT became better dispersed in the rubber matrices with elevated mixing temperatures (at which CBT was in partially molten state, which resulted in improved tensile properties. With increasing mixing temperature the size of the CBT particles in the compounds decreased significantly, from few hundred microns to 5–10 microns. Compounding at temperatures above 120 °C and 140 °C for NBR and SBR, respectively, yielded reduced tensile mechanical properties most likely due to the degradation of the base rubber. The viscosity reduction by CBT was more pronounced in mixes with coarser CBT dispersions prepared at lower mixing temperatures.

  8. The influence of manganese-cobalt oxide/graphene on reducing fire hazards of poly(butylene terephthalate).

    Science.gov (United States)

    Wang, Dong; Zhang, Qiangjun; Zhou, Keqing; Yang, Wei; Hu, Yuan; Gong, Xinglong

    2014-08-15

    By means of direct nucleation and growth on the surface of graphene and element doping of cobalt oxide (Co3O4) nano-particles, manganese-cobalt oxide/graphene hybrids (MnCo2O4-GNS) were synthesized to reduce fire hazards of poly(butylene terephthalate) (PBT). The structure, elemental composition and morphology of the obtained hybrids were surveyed by X-ray diffraction, X-ray photoelectron spectrometer and transmission electron microscopy, respectively. Thermogravimetric analysis was applied to simulate and study the influence of MnCo2O4-GNS hybrids on thermal degradation of PBT during combustion. The fire hazards of PBT and its composites were assessed by the cone calorimeter. The cone test results had showed that peak HRR and SPR values of MnCo2O4-GNS/PBT composites were lower than that of pure PBT and Co3O4-GNS/PBT composites. Furthermore, the incorporation of MnCo2O4-GNS hybrids gave rise to apparent decrease of pyrolysis products containing aromatic compounds, carbonyl compounds, carbon monoxide and carbon dioxide, attributed to combined impact of physical barrier for graphene and cat O4 for organic volatiles and carbon monoxide. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Solution viscosity – molar mass relationships for poly(butylene succinate and discussion on molar mass analysis

    Directory of Open Access Journals (Sweden)

    Q. Charlier

    2015-05-01

    Full Text Available Poly(butylene succinate (PBS is currently developing due to its biodegradability and the similarity of its mechanical properties to those of polyolefins. Relationships between the number average molar mass, Mn, and solution viscosity such as [η] and ηred were derived for this aliphatic polyester. Mn values were determined by end-group analysis and size exclusion chromatography (SEC. Mark-Houwink-Sakurada (MHS parameters were proposed in two solvents and for the different molar masses and viscosity measurement methods. As an example, the MHS equations were respectively, [η] =6.4•10–4•Mn0.67 in chloroform and [η] = 7.1•10–4•Mn0.69 in 50/50 wt% 1,2-dichlorobenzene/phenol at 25°C for molar masses measured by SEC in hexafluoro isopropanol (HFIP with poly(methyl methacrylate (PMMA standards. Empirical relationships were also suggested to derive Mn directly from reduced viscosity, ηred, which is much easier to determine than intrinsic viscosity. With these data, the number average molar mass of PBS can be conveniently estimated from a single viscosity measurement. In addition, it was shown that PBS contains 1–2 wt% of cyclic oligomers produced during esterification and that molar masses determined by taking this fraction into account or not were significantly different, especially for long chains.

  10. Preparation of surface-modified poly(butylene terephthalate) nonwovens and their application as leukocyte removal filters.

    Science.gov (United States)

    Kim, Eun Jin; Yeo, Gwu-Dong; Pai, Chaul-Min; Kang, Inn-Kyu

    2009-08-01

    Blood transfusion-related adverse reactions have been reported to be caused by leukocytes in blood products. It is now generally accepted that it would be highly desirable to reduce leukocytes level as low as possible. In this study, melt-blown poly(butylene terephthalate) nonwoven (PBT-NW) was treated with a hydroxyapatite (HA) surface-modification method for removal of leukocytes from blood components. Acrylic acid was graft-polymerized onto the surface of the PBT-NW after oxygen plasma glow discharge treatment. The PBT-NW surface was covered with a thin layer of HA produced by immersing the polymer surface in an aqueous solution containing high concentrations of PO(4) (3-) and Ca(2+) after graft-polymerization of acrylic acid, which provided the nucleus for HA crystallization. The surface was characterized using water contact angles, attenuated total reflection-Fourier transform infrared (ATR-FT-IR), and electron spectroscopy for chemical analysis. When filtration was performed with a unit of red blood cell concentrates, HA-deposited PBT-NW (PBT-HA) removed 98.5% of the leukocytes and recovered 99.5% of the erythrocytes, suggesting that HA-deposited PBT-NW is a very promising blood filter for selective removal of leukocytes.

  11. Concurrent Enhancement of Multiple Properties in Reactively Processed Nanocomposites of Polylactide/Poly[(butylene succinate)-co-adipate] Blend and Organoclay

    CSIR Research Space (South Africa)

    Ojijo, Vincent O

    2014-05-01

    Full Text Available stream_source_info Ojijo2_2014_ABSTRACT ONLY.pdf.txt stream_content_type text/plain stream_size 1813 Content-Encoding UTF-8 stream_name Ojijo2_2014_ABSTRACT ONLY.pdf.txt Content-Type text/plain; charset=UTF-8... Macromolecular Materials and Engineering Vol. 299(5), pp 596- 608 Concurrent Enhancement of Multiple Properties in Reactively Processed Nanocomposites of Polylactide/Poly[(butylene succinate)-co-adipate] Blend and Organoclaya Vincent Ojijo, Suprakas Sinha...

  12. Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) elastomer via photo-initiated graft polymerization of poly(ethylene glycol)

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiaomeng [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Luan Shifang, E-mail: sfluan@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yang Huawei; Shi Hengchong; Zhao Jie; Jin Jing [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yin Jinghua, E-mail: yinjh@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Stagnaro, Paola [Istituto per Io Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, Via de Marini 6, 16149 Genova (Italy)

    2012-01-15

    Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) copolymer biomedical elastomer was covalently grafted with poly(ethylene glycol) methyl ether methacrylate (PEGMA) via a photo-initiated graft polymerization technique. The surface graft polymerization of SEBS with PEGMA was verified by ATR-FTIR and XPS. Effect of graft polymerization parameters, i.e., monomer concentration, UV irradiation time and initiator concentration on the grafting density was investigated. Comparing with the virgin SEBS film, the PEGMA-modified SEBS film presented an enhanced wettability and a larger surface energy. Besides, the surface grafting of PEGMA imparted excellent anti-platelet adhesion and anti-protein adsorption to the SEBS surface.

  13. Comparative Studies on the Mechanical Properties of Nonwoven- and Woven-Flax-Fiber-Reinforced Poly(Butylene Adipate-Co-Terephthalate)-Based Composite Laminates

    Science.gov (United States)

    Phongam, N.; Dangtungee, R.; Siengchin, S.

    2015-03-01

    Textile biocomposites made from woven- and nonwoven-flax-fiber-reinforced poly(butylene adipate-co-terephthalate) (PBAT) were prepared by compression molding using the film stacking method, and their tensile strength and stiffness, flexural strength and modulus, and impact strength were determined experimentally. The PBAT-based composites were subjected to water absorption tests. The mechanical properties of pure PBAT and the textile composites were compared, and the influence of flax weave styles on the properties were evaluated. The biocomposite reinforced with 4 × 4-plain weave fibers showed the highest strength and stiffness compared with those of the other textile biocomposites and pure PBAT.

  14. Synthesis and characterization of a novel multiblock copolyester containing poly(ethylene succinate) and poly(butylene succinate)

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Qunying; He Yisong [Center for Degradable and Flame-Retardant Polymeric Materials (ERCPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Zeng Jianbing, E-mail: zengjianbing@scu.edu.cn [Center for Degradable and Flame-Retardant Polymeric Materials (ERCPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Huang Qing [Center for Degradable and Flame-Retardant Polymeric Materials (ERCPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Wang Yuzhong, E-mail: yzwang@email.scu.edu.cn [Center for Degradable and Flame-Retardant Polymeric Materials (ERCPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China)

    2011-11-01

    Highlights: {yields} High-molecular-weight biodegradable multiblock copolyester containing PBS and PES segments was achieved. {yields} PBS and PES are miscible with a single glass transition regardless of composition. {yields} The multiblock copolyester showed excellent tensile strength and elongation at break. {yields} The multiblock copolyester can serve as a potential substitute for conventional non-biodegradable commodity plastics. - Abstract: Multiblock copolyester (PBS-b-PES) containing poly(butylene succinate) (PBS) and poly(ethylene succinate) (PES) was successfully synthesized by chain-extension of dihydroxyl terminated PBS (HO-PBS-OH) and PES (HO-PES-OH) using 1,6-hexmethylene diisocyanate (HDI) as a chain extender. The chemical structures, molecular weights, crystallization behaviors, thermal and mechanical properties of the copolyesters were characterized by proton nuclear magnetic resonance spectroscopy ({sup 1}H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), wide-angle X-ray diffraction (WAXD), tensile testing and hydrolytic degradation. High-molecular-weight copolyesters with M{sub w} more than 2.0 x 10{sup 5} g mol{sup -1} were easily obtained through chain-extension. The copolyesters showed a single glass transition temperature (T{sub g}) which increased with PES content. The melting point temperature (T{sub m}) and relative degree of crystallinity (X{sub c}) of the copolyesters decreased first and then increased with PES content. The copolyesters manifested excellent mechanical properties, for example, PBS{sub 5}-b-PES{sub 5} had fracture stress of 61.8 MPa and fracture strain of 1173%. The chain-extension reaction provided a very effective way to produce high molecular weight multiblock copolyesters.

  15. Reinforcement effect of poly(butylene succinate) (PBS)-grafted cellulose nanocrystal on toughened PBS/polylactic acid blends.

    Science.gov (United States)

    Zhang, Xuzhen; Zhang, Yong

    2016-04-20

    Poly(butylene succinate) (PBS)/polylactic acid (PLA) blends modified with dicumyl peroxide (DCP) were reinforced by PBS-g-cellulose nanocrystal (CNC) through melt mixing. PBS-g-CNC was prepared through in situ polymerization and its structure was confirmed by FTIR, (13)C NMR, XPS and GPC analysis after saponification. The morphological analysis of PBS/PLA/PBS-g-CNC composites before and after etched by CH2Cl2 shows that the addition of DCP and PBS-g-CNC could decrease the size of PBS as a dispersed phase in PLA matrix and improve the dispersion of PBS-g-CNC in both PBS and PLA phases, which could affect the crystallization and mechanical properties of composites. The crystallinity of PLA α'-phase crystal in PBS/PLA/PBS-g-CNC composites is increased obviously by the addition of PBS-g-CNC, leading to an increase of the crystallinity of the composites. PBS/PLA blends modified by DCP have high Notched Izod impact strength and moduli, and the values are increased by the addition of PBS-g-CNC. Both storage modulus and glass translation temperature of PBS/PLA blend are increased by DCP and PBS-g-CNC, which is proved by DMA results, showing a weak molecular segment mobility of PBS/PLA matrix. The addition of DCP decreases the crystallization temperature and crystallinity of PBS/PLA composite, but increases the thermal stability of composites, mostly because of the crosslink effect of DCP on PBS/PLA matrix. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Toughening modification of poly(butylene terephthalate)/poly(ethylene terephthalate) blends by an epoxy-functionalized elastomer

    Science.gov (United States)

    Zhang, Weizhou; Wang, Kai; Yan, Wei; Guo, Weihong

    2017-10-01

    New toughened poly(butylene terephthalate) (PBT)/poly(ethylene terephthalate) (PET) (40/60 wt%) blends were obtained by melting with Glycidyl methacrylate grafted poly(ethylene octane) copolymer (POE-g-GMA), varying the POE-g-GMA content up to 20 wt%, in a twin-screw extruder, followed by injection molding. The influence of POE-g-GMA on the properties of the PBT/PET blends was investigated by mechanical testing, Fourier transform infrared (FT-IR) analysis, gel fractions analysis, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and scanning electronic microscopy (SEM). The mechanical testing results indicated that the incorporation of POE-g-GMA led to increases in the notched impact strength and decreases in the tensile strength, flexural strength, and flexural modulus. When POE-g-GMA content reached 20 wt%, the notched impact strength (8.0 kJ m‑2) was achieved for the PBT/PET/POE-g-GMA blends. FT-IR results proved that some PBT/PET/POE-g-GMA copolymers were produced, which improved the compatibility between POE-g-GMA and the PBT/PET matrix. The extent of crosslinking was observed by gel fraction measurements. DMA results further testified chain-extending and micro-crosslink reactions occurred between POE-g-GMA and PBT/PET blends. In addition, the reactions induced by POE-g-GMA affected the crystallization behavior of PBT/PET blends obviously, as observed from DSC results. By means of SEM observation of the impact fracture surface morphology, and the discussion of the micro-crosslink reaction process between the epoxide-containing elastomers and PBT/PET matrix, the toughening mechanism was proposed to be taken into account the shear yielding of PBT/PET matrix and cavitation of elastomer particles.

  17. Biocompatibility and drug release behavior of scaffolds prepared by coaxial electrospinning of poly(butylene succinate) and polyethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Llorens, E.; Ibañez, H. [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Valle, L.J. del, E-mail: luis.javier.del.valle@upc.edu [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Puiggalí, J. [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering (CrNE), Universitat Politècnica de Catalunya, Edifici C, C/Pasqual i Vila s/n, Barcelona E-08028 (Spain)

    2015-04-01

    Scaffolds constituted by electrospun microfibers of poly(ethylene glycol) (PEG) and poly(butylene succinate) (PBS) were studied. Specifically, coaxial microfibers having different core–shell distributions and compositions were considered as well as uniaxial micro/nanofibers prepared from mixtures of both polymers. Processing conditions were optimized for all geometries and compositions and resulting morphologies (i.e. diameter and surface texture) characterized by scanning electron microscopy. Chemical composition, molecular interactions and thermal properties were evaluated by FTIR, NMR, XPS and differential scanning calorimetry. The PEG component of electrospun fibers could be solubilized by immersion of scaffolds in aqueous medium, giving rise to high porosity and hydrophobic samples. Nevertheless, a small amount of PEG was retained in the PBS matrix, suggesting some degree of mixing. Solubilization was slightly dependent on fiber structure; specifically, the distribution of PEG in the core or shell of coaxial fibers led to higher or lower retention levels, respectively. Scaffolds could be effectively loaded with hydrophobic drugs having antibacterial and anticarcinogenic activities like triclosan and curcumin, respectively. Their release was highly dependent on their chemical structure and medium composition. Thus, low and high release rates were observed in phosphate buffer saline (SS) and SS/ethanol (30:70 v/v), respectively. Slight differences in the release of triclosan were found depending on fiber distribution and composition. Antibacterial activity and biocompatibility were evaluated for both loaded and unloaded scaffolds. - Highlights: • Coaxial microfibers with different hydrophobicities were studied. • The surface morphology of the coaxial fiber shows the distribution of polymers. • Coaxial fiber microstructure favors the polymer molecular orientation. • These hybrid materials have greater advantages for loading and drug release. • PEG

  18. The influence of antioxidant and post-synthetic treatment on the properties of biodegradable poly(butylene succinates modified with poly(propylene oxide

    Directory of Open Access Journals (Sweden)

    DRAGANA PEPIC

    2007-12-01

    Full Text Available Novel poly(ester–ethers based on poly(butylene succinate (PBS as the hard segments and 30 mass % of poly(propylene oxide (PPO as the soft segments were synthesized with varying amount of the antioxidant (N,N'-diphenyl-p-phenylenediamine, DPPD. The influences of the addition of DPPD and the impact of post-synthetic treatment by precipitation on the molecular structure, thermal and physical properties, as well as on the storage stability of the biodegradable aliphatic copolyesters, were investigated. The structure and composition of the copolymers were determined by means of 1H-NMR spectroscopy. The molecular weight and polydispersity of the poly(ester–ethers were evaluated from solution viscosity and GPC measurements. The thermal properties and stability were evaluated, respecttively, by means of DSC and non-isothermal thermogravimetry in an inert nitrogen atmosphere. The biodegradability potential of the polymers was studied in hydrolytic and enzymatic degradation tests with Candida cylindracea lipase by monitoring the weight loss of polymer films after incubation. The weight losses of the samples increased with time and were in the range from 1 to 5 mass % after 4 weeks. GPC analysis confirmed that there were changes in the molecular weight of the copolyesters during both hydrolytic and enzymatic degradation tests, leading to the conclusion that the degradation mechanism of poly(butylenes succinate modified with PPO occurred through surface erosion and bulk degradation.

  19. Poly(butylene 2,5-furandicarboxylate-ε-caprolactone: A new bio-based elastomer with high strength and biodegradability

    Directory of Open Access Journals (Sweden)

    M. Y. Zheng

    2017-08-01

    Full Text Available A new bio-based elastomer, poly(butylene 2,5-furandicarboxylate-ε-caprolactone (PBFCL, has been synthesized from 2,5-furandicarboxylic acid, 1,4-butanediol, and ε-caprolactone successfully for the first time. The obtained copolyester was characterized in terms of chemical structure, thermal and mechanical properties, and enzymatic degradability. In PBFCL elastomer, butylene-2,5-furandiacrboxylate units (hard segments crystallize to serve as physical crosslinks while ε-caprolactone polyester diol (soft segments provide flexibility. PBFCL is a multi-blocked copolyester with randomly distributed rigid and soft segments. It possesses original feature of high strength and biodegradability stemming from the uses of aromatic and aliphatic monomers respectively. An important aspect of this new furanic-aliphatic polyester is its tailor-made properties simply achieved by changing the content of hard or soft segments. Typically, PBFCL-40 of optimal composition has Young’s modulus as low as 15.4 MPa, tensile strength as high 24.8 MPa, and elongation as long as 885%.

  20. 1, 6-diisocyanatohexane-extended poly (1, 4-butylene succinate / hydroxyl apatite nano particle scaffolds: Potential materials for bone regeneration applications

    Science.gov (United States)

    Kaur, Kulwinder; Singh, K. J.; Anand, Vikas; Bhatia, Gaurav; Nim, Lovedeep; Kaur, Manpreet; Arora, Daljit Singh

    2017-05-01

    Bioresorbable and bioactive scaffolds are promising materials for various biomedical applications including bone regeneration and drug delievrery. Authors present bioactive scaffolds prepared from 1, 6-diisocyanatohexane-extended poly (1, 4-butylene succinate) (PBSu-DCH) with different amount of hydroxyl apatite nanoparticles (nHAp) by solvent casting and particulate leaching techniques. Different weight ratios of nHAp (i.e. 0, 5 and 10 wt %) with fixed weight ratio (i.e. 10 wt %) of PBSu-DCH polymer have been prepared. Scaffolds have been assessed for their morphology, bioactivity, degradation, drug release and biological properties including cytotoxicity, cell attachment using MG-63 cell line and antimicrobial activity. Effectual drug release has been measured by incorporating gentamycin as an antibiotic in the scaffolds. The study is aimed at developing new biodegradable scaffolds to be used in skull, jaw and tooth socket for preserving bone mass.

  1. Enzymatic Synthesis of a Bio-Based Copolyester from Poly(butylene succinate) and Poly((R)-3-hydroxybutyrate): Study of Reaction Parameters on the Transesterification Rate.

    Science.gov (United States)

    Debuissy, Thibaud; Pollet, Eric; Avérous, Luc

    2016-12-12

    The enzyme-catalyzed synthesis of fully biobased poly(3-hydroxybutyrate-co-butylene succinate) (poly(HB-co-BS)) copolyesters is reported for the first time. Different Candida antarctica lipase B (CALB)-catalyzed copolyesters were produced in solution, via a one-step or a two-step process from 1,4-butanediol, diethyl succinate, and synthesized telechelic hydroxylated poly(3-hydroxybutyrate) oligomers (PHB-diol). The influence of the ester/hydroxyl functionality ratio, catalyst amount, PHB-diol oligomer chain length, hydroxybutyrate (HB) and butylene succinate (BS) contents, and the nature of the solvent were investigated. The two-step process allowed the synthesis of copolyesters of high molar masses (M n up to 18 000 g/mol), compared to the one-step process (M n ∼ 8000 g/mol), without thermal degradation. The highest molar masses were obtained with diphenyl ether as solvent, compared with dibenzyl ether or anisole. During the two-step process, the transesterification rate between the HB and BS segments (i) increased with increasing amount of catalyst and decreasing molar mass of the PHB-diol oligomer, (ii) decreased when anisole was used as the solvent, and (iii) was not influenced by the HB/BS ratio. Tendencies toward block or random macromolecular architectures were observed as a function of the reaction time, the PHB-diol oligomer chain length, and the chosen solvent. Immobilized CALB-catalyzed copolyesters were thermally stable up to 200 °C. The crystalline structure of the poly(HB-co-BS) copolyesters depended on the HB/BS ratio and the average sequence length of the segments. The crystalline content, T m and T c decreased with increasing HB content and the randomness of the copolymer structure.

  2. Miscibility, crystallization and mechanical properties of biodegradable blends of poly(L-lactic acid) and poly(butylene succinate-b-ethylene succinate) multiblock copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Ling; Huang, Cai-Li [Center for Degradable and Flame-Retardant Polymeric Materials, College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Zeng, Jian-Bing, E-mail: zengjianbing@scu.edu.cn [Center for Degradable and Flame-Retardant Polymeric Materials, College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Wang, Yu-Zhong [Center for Degradable and Flame-Retardant Polymeric Materials, College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China); Wang, Xiu-Li, E-mail: xiuliwang1@163.com [Center for Degradable and Flame-Retardant Polymeric Materials, College of Chemistry, State Key Laboratory of Polymer Materials Engineering, National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), Sichuan University, Chengdu 610064 (China)

    2012-07-10

    Highlights: Black-Right-Pointing-Pointer The blend of PLLA and PBES showed limited miscibility. Black-Right-Pointing-Pointer The crystallization rate of PLLA was accelerated by blending with PBES. Black-Right-Pointing-Pointer The crystal structures of PLLA and PBES did not change. - Abstract: Poly(L-lactic acid) (PLLA) is regarded as one of the most promising biobased and biodegradable polymers. However, its application was restricted due to the brittle nature. In the present study, PLLA was blended with a novel biodegradable flexible multiblock copolymer, poly(butylene succinate-b-ethylene succinate) (PBES) to produce new biodegradable materials. PLLA/PBES blends with different composition were prepared by solution blending and casting method with chloroform as a mutual solvent. Miscibility, crystallization behavior, and mechanical properties of the blends were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and tensile tests. The results indicated that PLLA and PBES showed limited miscibility in the amorphous phase. The crystallization rate of PLLA was accelerated with the increase of PBES in the blends while the crystallization mechanism did not change. The results of tensile tests suggest that the blends showed longer elongation at break than neat PLLA. The elongation at break of PLLA was obtained to be 10%, and those of PLLA/PBES 80/20, 60/40, 40/60 and 20/80 were 29, 110, 442, and 455%, respectively.

  3. Investigation on Polylactide (PLA/Poly(butylene adipate-co-terephthalate (PBAT/Bark Flour of Plane Tree (PF Eco-Composites

    Directory of Open Access Journals (Sweden)

    Qiang Dou

    2016-05-01

    Full Text Available Polylactide (PLA/poly(butylene adipate-co-terephthalate (PBAT/bark flour of plane tree (PF eco-composites were prepared via melt blending. The morphologies, mechanical properties, crystal structures and melting and crystallization behaviors of the eco-composites were investigated by means of scanning electron microscopy (SEM, mechanical tests, polarized light microscopy (PLM, wide angle X-ray diffraction (WAXD and differential scanning calorimetry (DSC, respectively. It is shown that the interfacial adhesion between PLA matrix and PF is weak and the mechanical properties of PLA/PF eco-composites are poor. The titanate treatment improves the adhesion between the matrix and the filler and enhances the stiffness of the eco-composites. The toughness is improved by PBAT and ductile fractured surfaces can be found. The spherulitic size of PLA is decreased by the addition of PF. The α crystalline form of PLA remains in the composites. Compared with PF, T-PF (PF treated by a titanate coupling agent and PBAT have negative effects on the crystallization of PLA.

  4. How Stress Treatments Influence the Performance of Biodegradable Poly(Butylene Succinate-Based Copolymers with Thioether Linkages for Food Packaging Applications

    Directory of Open Access Journals (Sweden)

    Valentina Siracusa

    2017-08-01

    Full Text Available Biodegradable poly(butylene succinate (PBS-based random copolymers containing thioether linkages (P(BSxTDGSy of various compositions have been investigated and characterized from the gas barrier, thermal, and mechanical point of view, after food contact simulants or thermal and photoaging processes. Each stress treatment was performed on thin films and the results obtained have been compared to the same untreated film, used as a standard. Barrier properties with different gases (O2 and CO2 were evaluated, showing that the polymer chemical composition strongly influenced the permeability behavior. The relationships between the diffusion coefficients (D and solubility (S with polymer composition were also investigated. The results highlighted a correlation between polymer chemical structure and treatment. Gas transmission rate (GTR mainly depending on the performed treatment, as GTR increased with the increase of TDGS co-unit amount. Thermal and mechanical tests allowed for the recording of variations in the degree of crystallinity and in the tensile properties. An increase in the crystallinity degree was recorded after contact with simulant liquids and aging treatments, together with a molecular weight decrease, a slight enhancement of the elastic modulus and a decrement of the elongation at break, proportional to the TDGS co-unit content.

  5. Investigation on sodium benzoate release from poly(butylene adipate-co-terephthalate)/organoclay/sodium benzoate based nanocomposite film and their antimicrobial activity.

    Science.gov (United States)

    Mondal, Dibyendu; Bhowmick, Biplab; Maity, Dipanwita; Mollick, Md Masud R; Rana, Dipak; Rangarajan, Vivek; Sen, Ramkrishna; Chattopadhyay, Dipankar

    2015-03-01

    Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significance, mainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate-co-terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process. A homogenous dispersion of organoclay (cetyltrimethylammonium-modified montmorillonite [CMMT]) in PBAT matrix was observed by X-ray diffraction and transmission electron microscopy. PBAT/CMMT nanocomposite film showed higher barrier properties against water and methanol vapor compared to the PBAT film. The release of SB from PBAT and its nanocomposite film was measured and the relevant data were fitted to the Weibull model. The higher values of Weibull's shape factor and scale parameter as corroborated by experimental findings indicated faster rate of SB release from PBAT/CMMT/SB nanocomposite film, when compared to the pristine PBAT film. Bacterial inhibition studies were accomplished against 2 food pathogenic bacteria, Bacillus subtilis and Staphylococcus aureus, by determining the zone of inhibition and corresponding growth profiles. Both bacterial inhibition studies and growth profiles established that PBAT/CMMT/SB demonstrated better antimicrobial activity than PBAT/SB film. Therefore, PBAT/CMMT/SB nanocomposite film can be used for food packaging application as it showed good barrier properties and antimicrobial activity against food pathogenic bacteria. © 2015 Institute of Food Technologists®

  6. Effect of nanoclay loading on the thermal and mechanical properties of biodegradable polylactide/poly[(butylene succinate)-co-adipate] blend composites.

    Science.gov (United States)

    Ojijo, Vincent; Sinha Ray, Suprakas; Sadiku, Rotimi

    2012-05-01

    Polylactide/poly[(butylene succinate)-co-adipate] (PLA/PBSA)-organoclay composites were prepared via melt compounding in a batch mixer. The weight ratio of PLA to PBSA was kept at 70:30, while the weight fraction of the organoclay was varied from 0 to 9%. Small angle X-ray scattering patterns showed slightly better dispersion in PBSA than PLA, and there was a tendency of the silicate layers to delaminate in PBSA at low clay content. Thermal analysis revealed that crystallinity was dependent on the clay content as well its localization within the composite. On the other hand, thermal stability marginally improved for composites with 2 wt %. Tensile properties showed dependence on clay content and localization. Composite with 2 wt % clay content showed slight improvement in elongation at break. Overall, the optimum property was found for a composite with 2 wt % of the organoclay. This paper therefore has demonstrated the significance of the clay content and localization on the properties of the PLA/PBSA blends.

  7. Role of specific interfacial area in controlling properties of immiscible blends of biodegradable polylactide and poly[(butylene succinate)-co-adipate].

    Science.gov (United States)

    Ojijo, Vincent; Sinha Ray, Suprakas; Sadiku, Rotimi

    2012-12-01

    Binary blends of two biodegradable polymers: polylactide (PLA), which has high modulus and strength but is brittle, and poly[(butylene succinate)-co-adipate] (PBSA), which is flexible and tough, were prepared through batch melt mixing. The PLA/PBSA compositions were 100/0, 90/10, 70/30, 60/40, 50/50, 40/60, 30/70, 10/90, and 0/100. Fourier-transform infrared measurements revealed the absence of any chemical interaction between the two polymers, resulting in a phase-separated morphology as shown by scanning electron microscopy (SEM). SEM micrographs showed that PLA-rich blends had smaller droplet sizes when compared to the PBSA-rich blends, which got smaller with the reduction in PBSA content due to the differences in their melt viscosities. The interfacial area of PBSA droplets per unit volume of the blend reached a maximum in the 70PLA/30PBSA blend. Thermal stability and mechanical properties were not only affected by the composition of the blend, but also by the interfacial area between the two polymers. Through differential scanning calorimetry, it was shown that molten PBSA enhanced crystallization of PLA while the stiff PLA hindered cold crystallization of PBSA. Optimal synergies of properties between the two polymers were found in the 70PLA/30PBSA blend because of the maximum specific interfacial area of the PBSA droplets.

  8. Effect of Fiber Esterification on Fundamental Properties of Oil Palm Empty Fruit Bunch Fiber/Poly(butylene adipate-co-terephthalate Biocomposites

    Directory of Open Access Journals (Sweden)

    Mohamad Zaki AB Rahman

    2012-01-01

    Full Text Available A new class of biocomposites based on oil palm empty fruit bunch fiber and poly(butylene adipate-co-terephthalate (PBAT, which is a biodegradable aliphatic aromatic co-polyester, were prepared using melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 wt% and characterized. Chemical treatment of oil palm empty fruit bunch (EFB fiber was successfully done by grafting succinic anhydride (SAH onto the EFB fiber surface, and the modified fibers were obtained in two levels of grafting (low and high weight percentage gain, WPG after 5 and 6 h of grafting. The FTIR characterization showed evidence of successful fiber esterification. The results showed that 40 wt% of fiber loading improved the tensile properties of the biocomposite. The effects of EFB fiber chemical treatments and various organic initiators content on mechanical and thermal properties and water absorption of PBAT/EFB 60/40 wt% biocomposites were also examined. The SAH-g-EFB fiber at low WPG in presence of 1 wt% of dicumyl peroxide (DCP initiator was found to significantly enhance the tensile and flexural properties as well as water resistance of biocomposite (up to 24% compared with those of untreated fiber reinforced composites. The thermal behavior of the composites was evaluated from thermogravimetric analysis (TGA/differential thermogravimetric (DTG thermograms. It was observed that, the chemical treatment has marginally improved the biocomposites’ thermal stability in presence of 1 wt% of dicumyl peroxide at the low WPG level of grafting. The improved fiber-matrix surface enhancement in the chemically treated biocomposite was confirmed by SEM analysis of the tensile fractured specimens.

  9. Novel ether-linkages containing aliphatic copolyesters of poly(butylene 1,4-cyclohexanedicarboxylate) as promising candidates for biomedical applications.

    Science.gov (United States)

    Gigli, Matteo; Lotti, Nadia; Vercellino, Marco; Visai, Livia; Munari, Andrea

    2014-01-01

    A new class of biodegradable and biocompatible poly(butylene 1,4-cyclohexanedicarboxylate) based random copolymers are proposed for biomedical applications. The introduction of ether-oxygen containing BDG sequences along the PBCE macromolecular chain is expected to remarkably improve chain flexibility and surface hydrophilicity due to the presence of highly electronegative oxygen atoms. P(BCExBDGy) copolymers were synthesized by polycondensation. The homopolymer PBCE and three copolymers, namely (P(BCE70BDG30), P(BCE55BDG45) and P(BCE40BDG60)) were characterized from the molecular, thermal, structural and mechanical point of view. Hydrolytic degradation studies in the presence and absence of hog-pancreas lipase were performed under physiological conditions. To evaluate the diffusion profile of small molecules through the polymer matrix, the release behaviour of fluorescein isothiocyanate (FITC) was investigated. For biocompatibility studies, cell adhesion and proliferation of murine fibroblast (L929) and endocrine pancreatic (INS-1) cells were performed on each polymeric film. Results showed that solid-state properties can be tailored by simply varying copolymers' composition. Crystallinity degree and hydrophobicity significantly decreased with the increase of BDG co-unit mol%. Moreover, mechanical properties and biodegradability of PBCE, both depending on crystallinity degree, were remarkably improved: P(BCE40BDG60) showed an elastomeric behaviour with εb over 600% and, as regard to biodegradability, after 98days it lost over 60% of its initial weight if incubated in the presence of the pancreatic lipase. Lastly, the newly developed biomaterials resulted not cytotoxic with both types of cells and could be properly tailored for biomedical applications varying the content of BDG co-unit mol%. © 2013.

  10. The impact of DO and salinity on microbial community in poly(butylene succinate) denitrification reactors for recirculating aquaculture system wastewater treatment.

    Science.gov (United States)

    Deng, Ya-Le; Ruan, Yun-Jie; Zhu, Song-Ming; Guo, Xi-Shan; Han, Zhi-Ying; Ye, Zhang-Ying; Liu, Gang; Shi, Ming-Ming

    2017-12-01

    The interactions between environmental factors and bacterial community shift in solid-phase denitrification are crucial for optimum operation of a reactor and to achieve maximum treatment efficiency. In this study, Illumina high-throughput sequencing was applied to reveal the effects of different operational conditions on bacterial community distribution of three continuous operated poly(butylene succinate) biological denitrification reactors used for recirculating aquaculture system (RAS) wastewater treatment. The results indicated that salinity decreased OTU numbers and diversity while dissolved oxygen (DO) had no obvious influence on OTU numbers. Significant microbial community composition differences were observed among and between three denitrification reactors under varied operation conditions. This result was also demonstrated by cluster analysis (CA) and detrended correspondence analysis (DCA). Hierarchical clustering and redundancy analysis (RDA) was performed to test the relationship between environmental factors and bacterial community compositions and result indicated that salinity, DO and hydraulic retention time (HRT) were the three key factors in microbial community formation. Besides, Simplicispira was detected under all operational conditions, which worth drawing more attention for nitrate removal. Moreover, the abundance of nosZ gene and 16S rRNA were analyzed by real-time PCR, which suggested that salinity decreased the proportion of denitrifiers among whole bacterial community while DO had little influence on marine reactors. This study provides an overview of microbial community shift dynamics in solid-phase denitrification reactors when operation parameters changed and proved the feasibility to apply interval aeration for denitrification process based on microbial level, which may shed light on improving the performance of RAS treatment units.

  11. Osteoconductive bio-based meshes based on Poly(hydroxybutyrate-co-hydroxyvalerate) and poly(butylene adipate-co-terephthalate) blends

    Energy Technology Data Exchange (ETDEWEB)

    Nar, Mangesh; Staufenberg, Gerrit; Yang, Bing [Department of Material Science and Engineering, University of North Texas, 1155 Union Circle #305310, Denton, TX 76203-5017 (United States); Robertson, Lesli [Department of Fibers, College of Visual Arts and Design, 1155 Union Circle #305100, Denton, TX 76203-5017 (United States); Patel, Rinkesh H. [Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A and M University Baylor College of Dentistry, Dallas, TX 75246 (United States); Varanasi, Venu G., E-mail: vvaranasi@bcd.tamhsc.edu [Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A and M University Baylor College of Dentistry, Dallas, TX 75246 (United States); D' Souza, Nandika Anne, E-mail: nandika.dsouza@unt.edu [Department of Material Science and Engineering, University of North Texas, 1155 Union Circle #305310, Denton, TX 76203-5017 (United States); Department of Mechanical and Energy Engineering, University of North Texas, 1155 Union Circle # 311098, Denton, TX 76203-5017 (United States)

    2014-05-01

    Poly(butylene adipate-co-terephthalate) (PBAT) and Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) are biopolymers that have the potential to be used in applications of bone healing. In this study, it is hypothesized that the polymer blend has the combined strength and osteoconductivity to support osteoblast collagen formation. PBAT (PBAT 100), and a blend with 20% PHBV (PBAT 80) were extruded in the form of fibers and then knitted in the form of mesh. These were tested in the warp as well as weft direction for the tensile properties; these showed that the weft direction had higher performance than the warp. The individual fibers were kept in phosphate buffered saline (PBS) over the period of 8 weeks and were tested for the storage and loss modulus using a dynamic mechanical analyser (DMA). The results indicated that mechanical relaxation strength showed a decrease and then an increase. In vitro osteoconductivity studies were done by using differentiating osteoblasts (MC3T3-E1 subclone 4 cells). Environmental Scanning Electron Microscopy (ESEM) showed that pre-soaking the samples in α-MEM for two weeks resulted in cell attachment and growth. X-ray diffraction (XRD) was used to determine the change in structure of polymers due to in vitro degradation for two weeks. Raman spectroscopy showed that all scaffolds supported the formation of a collagenous network over the scaffold surfaces. For a combination of knittable manufacturing, mechanical performance and osteoconductivity, blends offer an effective route. - Highlights: • PBAT and PHBV blend can be knitted to form mesh with good mechanical properties. • PBAT and PHBV blend do not show significant weight loss over a period of 8 weeks in PBS. • Osteoblast cell culture was done on these samples. • They support extracellular matrix and growth and hence are osteoconductive.

  12. Novel ether-linkages containing aliphatic copolyesters of poly(butylene 1,4-cyclohexanedicarboxylate) as promising candidates for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Gigli, Matteo [Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), University of Bologna, Via Terracini 28, 40131 Bologna (Italy); Lotti, Nadia, E-mail: nadia.lotti@unibo.it [Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), University of Bologna, Via Terracini 28, 40131 Bologna (Italy); Vercellino, Marco [Department of Molecular Medicine, UdR of INSTM, Viale Taramelli 3/B, University of Pavia, Pavia (Italy); Visai, Livia [Department of Molecular Medicine, UdR of INSTM, Viale Taramelli 3/B, University of Pavia, Pavia (Italy); Department of Occupational Medicine, Ergonomics and Disability, Salvatore Maugeri Foundation, IRCCS, Laboratory of Nanotechnology, Via S. Maugeri 8, 27100 Pavia (Italy); Munari, Andrea [Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), University of Bologna, Via Terracini 28, 40131 Bologna (Italy)

    2014-01-01

    A new class of biodegradable and biocompatible poly(butylene 1,4-cyclohexanedicarboxylate) based random copolymers are proposed for biomedical applications. The introduction of ether–oxygen containing BDG sequences along the PBCE macromolecular chain is expected to remarkably improve chain flexibility and surface hydrophilicity due to the presence of highly electronegative oxygen atoms. P(BCExBDGy) copolymers were synthesized by polycondensation. The homopolymer PBCE and three copolymers, namely (P(BCE70BDG30), P(BCE55BDG45) and P(BCE40BDG60)) were characterized from the molecular, thermal, structural and mechanical point of view. Hydrolytic degradation studies in the presence and absence of hog-pancreas lipase were performed under physiological conditions. To evaluate the diffusion profile of small molecules through the polymer matrix, the release behaviour of fluorescein isothiocyanate (FITC) was investigated. For biocompatibility studies, cell adhesion and proliferation of murine fibroblast (L929) and endocrine pancreatic (INS-1) cells were performed on each polymeric film. Results showed that solid-state properties can be tailored by simply varying copolymers' composition. Crystallinity degree and hydrophobicity significantly decreased with the increase of BDG co-unit mol%. Moreover, mechanical properties and biodegradability of PBCE, both depending on crystallinity degree, were remarkably improved: P(BCE40BDG60) showed an elastomeric behaviour with ε{sub b} over 600% and, as regard to biodegradability, after 98 days it lost over 60% of its initial weight if incubated in the presence of the pancreatic lipase. Lastly, the newly developed biomaterials resulted not cytotoxic with both types of cells and could be properly tailored for biomedical applications varying the content of BDG co-unit mol%. - Highlights: • Ether–oxygen atoms along PBCE chain as winning strategy to improve its properties • Adjustable solid-state properties of copolymers simply

  13. Cage-like mesoporous organosilicas with isocyanurate bridging groups synthesized by soft templating with poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) block copolymer.

    Science.gov (United States)

    Grudzien, Rafal M; Blitz, Jonathan P; Pikus, Stanislaw; Jaroniec, Mietek

    2009-05-01

    Ordered large-pore organosilicas with isocyanurate bridging groups were synthesized via co-condensation of tetraethyl orthosilicate (TEOS) and tris[3-(trimethoxysilyl)propyl]isocyanurate (ICS) in the presence of poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) (EO(39)BO(47)EO(39)) B50-6600 template under acidic conditions. It was shown that the extraction of the B60-5500 triblock copolymer with acidified ethanol solution was insufficient to remove completely the template; however, calcination of as-synthesized and extracted samples under air atmosphere at 200 degrees C, 250 degrees C and 300 degrees C caused not only the removal of the polymer but also a substantial decomposition of the ICS groups. In contrast, the heat treatment of extracted organosilicas at 360 degrees C in flowing nitrogen was able to fully remove the residual template without degradation of the ICS bridging groups. Characterization of the resulting materials by small angle X-ray scattering (SAXS) and X-ray powder diffraction (XRD) revealed that isocyanurate-containing organosilicas have a body-centered cubic symmetry (Im3m). Argon adsorption-desorption isotherms of these organosilicas revealed cage-like mesopores, high surface areas and large pore volumes. The diameters of spherical cages were found to be very uniform in the range of 12-14 nm. A complete removal of triblock copolymer was confirmed by high-resolution thermogravimetry (TG), Fourier transform infrared spectroscopy (FT-IR) and CHNS elemental analysis (EA). The latter showed that the isocyanurate rings are intact in the framework and their loading is up to 1 mmol g(-1). Moreover, these organosilicas were also synthesized using low acid concentration, double amount of polymer and sodium chloride; in this case the template was completely extracted and there was no need for additional heat treatment.

  14. O6-2'-Deoxyguanosine-butylene-O6-2'-deoxyguanosine DNA Interstrand Cross-Links Are Replication-Blocking and Mutagenic DNA Lesions.

    Science.gov (United States)

    Xu, Wenyan; Kool, Daniel; O'Flaherty, Derek K; Keating, Ashley M; Sacre, Lauralicia; Egli, Martin; Noronha, Anne; Wilds, Christopher J; Zhao, Linlin

    2016-11-21

    DNA interstrand cross-links (ICLs) are cytotoxic DNA lesions derived from reactions of DNA with a number of anti-cancer reagents as well as endogenous bifunctional electrophiles. Deciphering the DNA repair mechanisms of ICLs is important for understanding the toxicity of DNA cross-linking agents and for developing effective chemotherapies. Previous research has focused on ICLs cross-linked with the N7 and N2 atoms of guanine as well as those formed at the N6 atom of adenine; however, little is known about the mutagenicity of O 6 -dG-derived ICLs. Although less abundant, O 6 -alkylated guanine DNA lesions are chemically stable and highly mutagenic. Here, O 6 -2'-deoxyguanosine-butylene-O 6 -2'-deoxyguanosine (O 6 -dG-C4-O 6 -dG) is designed as a chemically stable ICL, which can be induced by the action of bifunctional alkylating agents. We investigate the DNA replication-blocking and mutagenic properties of O 6 -dG-C4-O 6 -dG ICLs during an important step in ICL repair, translesion DNA synthesis (TLS). The model replicative DNA polymerase (pol) Sulfolobus solfataricus P2 DNA polymerase B1 (Dpo1) is able to incorporate a correct nucleotide opposite the cross-linked template guanine of ICLs with low efficiency and fidelity but cannot extend beyond the ICLs. Translesion synthesis by human pol κ is completely inhibited by O 6 -dG-C4-O 6 -dG ICLs. Moderate bypass activities are observed for human pol η and S. solfataricus P2 DNA polymerase IV (Dpo4). Among the pols tested, pol η exhibits the highest bypass activity; however, 70% of the bypass products are mutagenic containing substitutions or deletions. The increase in the size of unhooked repair intermediates elevates the frequency of deletion mutation. Lastly, the importance of pol η in O 6 -dG-derived ICL bypass is demonstrated using whole cell extracts of Xeroderma pigmentosum variant patient cells and those complemented with pol η. Together, this study provides the first set of biochemical evidence for the

  15. Influence of low contents of superhydrophilic MWCNT on the properties and cell viability of electrospun poly (butylene adipate-co-terephthalate) fibers

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Bruno V.M.; Silva, Aline S. [Laboratory of Biomedical Nanotechnology, Institute of Research and Development - IP& D, University of Vale do Paraiba (UNIVAP), Av. Shishima Hifumi 2911, Sao Jose dos Campos, Sao Paulo (Brazil); Melo, Gabriela F.S.; Vasconscellos, Luana M.R. [Department of Bioscience and Oral Diagnosis, Institute of Science and Technology, Sao Paulo State University (UNESP), Av. Engenheiro Francisco Jose Longo 777, Sao Jose dos Campos, Sao Paulo (Brazil); Marciano, Fernanda R. [Laboratory of Biomedical Nanotechnology, Institute of Research and Development - IP& D, University of Vale do Paraiba (UNIVAP), Av. Shishima Hifumi 2911, Sao Jose dos Campos, Sao Paulo (Brazil); Lobo, Anderson O., E-mail: aolobo@pq.cnpq.br [Laboratory of Biomedical Nanotechnology, Institute of Research and Development - IP& D, University of Vale do Paraiba (UNIVAP), Av. Shishima Hifumi 2911, Sao Jose dos Campos, Sao Paulo (Brazil)

    2016-02-01

    The use of poly (butylene adipate-co-terephthalate) (PBAT) in tissue engineering, more specifically in bone regeneration, has been underexplored to date due to its poor mechanical resistance. In order to overcome this drawback, this investigation presents an approach into the preparation of electrospun nanocomposite fibers from PBAT and low contents of superhydrophilic multi-walled carbon nanotubes (sMWCNT) (0.1–0.5 wt.%) as reinforcing agent. We employed a wide range of characterization techniques to evaluate the properties of the resulting electrospun nanocomposites, including Field Emission Scanning Electronic Microscopy (FE-SEM), Transmission Electronic Microscopy (TEM), tensile tests, contact angle measurements (CA) and biological assays. FE-SEM micrographs showed that while the addition of sMWCNT increased the presence of beads on the electrospun fibers' surfaces, the increase of the neat charge density due to their presence reduced the fibers' average diameter. The tensile test results pointed that sMWCNT acted as reinforcement in the PBAT electrospun matrix, enhancing its tensile strength (from 1.3 to 3.6 MPa with addition of 0.5 wt.% of sMWCNT) and leading to stiffer materials (lower elongation at break). An evaluation using MG63 cells revealed cell attachment into the biomaterials and that all samples were viable for biomedical applications, once no cytotoxic effect was observed. MG-63 cells osteogenic differentiation, measured by ALP activity, showed that mineralized nodules formation was increased in PBAT/0.5%CNTs when compared to control group (cells). This investigation demonstrated a feasible novel approach for producing electrospun nanocomposites from PBAT and sMWCNT with enhanced mechanical properties and adequate cell viability levels, which allows for a wide range of biomedical applications for these materials. - Highlights: • Nanocomposites from PBAT and superhydrophilic MWCNT (sMWCNT) were successfully prepared by electrospinning

  16. Preparation of nanocomposites based on poly(Butylene Succinate) and montmorillonite organoclay via in situ polymerization; Preparo de nanocompositos de poli(succinato de butileno) (PDS) e argila motmorilonita organofilica via polimerizaco in situ

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Leticia P.; Moreira, Andrei N.; Souza Junior, Fernando G. de, E-mail: fgsj@ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas; Pinto, Jose Carlos Costa da Silva [Coordenacao dos Cursos de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Quimica

    2014-09-15

    Nanocomposites based on poly(butylene succinate) (PBS) and organophilic montmorillonite were synthesized via in situ polymerization using three different clay compositions (4, 6 and 8 wt%). The products were characterized by several different techniques. X-ray diffraction was useful to confirm the increase of the interlayer spacing of the clay due to the presence of the polymer chains among layers. Thermal analysis indicated that the polymerization method chosen led to materials with lower thermal stability compared to the pure PBS, due to the difficulty of chain growth in the presence of the clay. Low-field NMR technique was used to assess clay dispersion in the polymer, with exfoliated structures predominating in the nanocomposites. (author)

  17. The Influence of Green Surface Modification of Oil Palm Mesocarp Fiber by Superheated Steam on the Mechanical Properties and Dimensional Stability of Oil Palm Mesocarp Fiber/Poly(butylene succinate Biocomposite

    Directory of Open Access Journals (Sweden)

    Yoon Yee Then

    2014-08-01

    Full Text Available In this paper, superheated steam (SHS was used as cost effective and green processing technique to modify oil palm mesocarp fiber (OPMF for biocomposite applications. The purpose of this modification was to promote the adhesion between fiber and thermoplastic. The modification was carried out in a SHS oven at various temperature (200–230 °C and time (30–120 min under normal atmospheric pressure. The biocomposites from SHS-treated OPMFs and poly(butylene succinate (PBS at a weight ratio of 70:30 were prepared by melt blending technique. The mechanical properties and dimensional stability of the biocomposites were evaluated. This study showed that the SHS treatment increased the roughness of the fiber surface due to the removal of surface impurities and hemicellulose. The tensile, flexural and impact properties, as well as dimensional stability of the biocomposites were markedly enhanced by the presence of SHS-treated OPMF. Scanning electron microscopy analysis showed improvement of interfacial adhesion between PBS and SHS-treated OPMF. This work demonstrated that SHS could be used as an eco-friendly and sustainable processing method for modification of OPMF in biocomposite fabrication.

  18. Biodegradation of Poly(butylene succinate Powder in a Controlled Compost at 58 °C Evaluated by Naturally-Occurring Carbon 14 Amounts in Evolved CO2 Based on the ISO 14855-2 Method

    Directory of Open Access Journals (Sweden)

    Masahiro Funabashi

    2009-09-01

    Full Text Available The biodegradabilities of poly(butylene succinate (PBS powders in a controlled compost at 58 °C have been studied using a Microbial Oxidative Degradation Analyzer (MODA based on the ISO 14855-2 method, entitled “Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions—Method by analysis of evolved carbon dioxide—Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test”. The evolved CO2 was trapped by an additional aqueous Ba(OH2 solution. The trapped BaCO3 was transformed into graphite via a serial vaporization and reduction reaction using a gas-tight tube and vacuum manifold system. This graphite was analyzed by accelerated mass spectrometry (AMS to determine the percent modern carbon [pMC (sample] based on the 14C radiocarbon concentration. By using the theory that pMC (sample was the sum of the pMC (compost (109.87% and pMC (PBS (0% as the respective ratio in the determined period, the CO2 (respiration was calculated from only one reaction vessel. It was found that the biodegradabilities determined by the CO2 amount from PBS in the sample vessel were about 30% lower than those based on the ISO method. These differences between the ISO and AMS methods are caused by the fact that part of the carbons from PBS are changed into metabolites by the microorganisms in the compost, and not changed into CO2.

  19. Performance of polyethylene based radiation grafted anion exchange membrane with polystyrene-b-poly (ethylene/butylene)-b-polystyrene based ionomer using NiCo2O4 catalyst for water electrolysis

    Science.gov (United States)

    Gupta, Gaurav; Scott, Keith; Mamlouk, Mohamed

    2018-01-01

    A soluble anion exchange ionomer with high OH- ion conductivity comparable to that of H+ conductivity of Nafion is synthesised by chloromethylation of polystyrene-b-poly (ethylene/butylene)-b-polystyrene (SEBS) and used with NiCo2O4 electro-catalyst for water electrolysis. The ionomer has an ion exchange capacity of 1.9 mmol g-1 and ionic conductivity of 0.14 S cm-2 at 50 °C. The cell voltage at 20 °C at 100 mA cm-2 is 1.77 and 1.72 V in, 0.1 and 1.0 M NaOH, respectively, for an optimum loading of 10 mg cm-2 NiCo2O4. At 10 mg cm-2 NiCo2O4 electrolyser cell performance is at least equal to or superior to that of IrO2 at 2 mg cm-2 with excellent stability over 1 h. When the catalyst is sprayed on the GDL instead of CCM, the performance is further improved to 1.65 V at 100 mA cm-2 at 60 °C & 0.1 M KOH. The limited AEM electrolyser performance when operating with deionised water in comparison to PEM and alkaline electrolyser arises from the sluggish OER in the AEM environment equivalent to pH of 11.5 and the two orders of magnitude lower HER activity with respect to acid medium combined with the high Tafel slope of 120 mV dec-1.

  20. Study of the mechanical behavior of thermo reversible gels of PS-b-poly(ethylene/butylene)-b-PS triblock copolymers in a selective solvent for the middle block of the copolymer; Estudio del comportamiento mecanico de geles fisicos termoreversibles obtenidos a partir de copolimeros tribloques de PS-b-poli(etileno/butileno)-PS en un disolvente selectivo del bloque central

    Energy Technology Data Exchange (ETDEWEB)

    Hernaez, E.; Inchausti, I.; Quintana, J. R.; Katime, I.

    2001-07-01

    The thermo reversible gelation of three triblock copolymers polystyrene-b-poly(ethylene/butylene)-b-polystyrene, with different molar mass and a similar chemical composition, in n-octane was studied. The solvent is selective for the middle poly(ethylene/butylene) block of the copolymers. the influence of the molar mass of the three copolymers on the gelation and on the mechanical properties of the gels was analysed. The sol-gel transition temperatures. T{sub g}el have been determined and they increase with the copolymer concentration and the copolymer molar mass. On the other land, the mechanical properties of the different gels were examined through oscillatory shear and compressive stress relaxation measurements. The concentration dependence of the elastic storage modules, G' for the three copolymer studied fit a sole straight line in a double-logarithmic scale and its slope (2.22) is close to that expected for systems in good solvents (2.25). As the temperature is near to the sol-gel transition temperate, the elastic modulus are smaller and the relaxation rates are higher. (Author) 12 refs.

  1. Magnetic and dielectric properties of sulfonated (S) poly[(styrene)-(ethylene-co-butylene)]-styrene (SEBS) block copolymer/magnetic metal oxide nanocomposites synthesized via an in-situ precipitation method

    Science.gov (United States)

    Peddini, Sateesh Kumar

    Block copolymer/magnetic metal oxide nanocomposites were synthesized by growing metal oxide nanoparticles (cobalt ferrite, CoFe2O 4 and iron oxide, alpha-Fe2O3) in sulfonated (s) poly (styrene) (PS) block domains of sulfonated poly [(styrene)-(ethylene-co-butylene)-(styrene)] (SEBS) BCP preformed films via an in-situ precipitation method by dissolving the salts of respective metal chloride (s) in a suitable solvent that selectively swells the sPS regions. Inorganic uptake was determined using thermogravimetric analysis (TGA), and it was observed that none of the samples incorporated more than 5 wt % of the inorganic component. Dynamical mechanical analysis was used to observe the changes in the glass transition temperatures (T g) in both blocks of the BCP by plotting tan delta vs. temperature responses in tensile mode on all samples. The results showed that the T g of the sPS block domains increased with sulfonation level and further increased with the incorporation of both nanoparticles in the same blocks, indicating that growth of nanoparticles takes place only in sPS blocks. The crystalline structure of the nanoparticles was observed using wide angle X-ray diffractometry (WAXD), and it was determined that cobalt iron oxide nanoparticles in 20 mole % sulfonated SEBS exhibited an inverse spinel structure confirming the structure to be CoFe2O4. And with iron oxide nanoparticles in 10 mole % sulfonated SEBS exhibiting a hematite (alpha-Fe2O 3) phase. Transmission electron microscopy (TEM) was used to investigate the particle size and distribution of nanoparticles in sBCP matrices at all sulfonation levels. Select area electron diffraction in TEM was used to determine crystalline structures of individual nanoparticles to compare with the structure observed from WAXD. The changes in thickness of interfaces between the individual PS and EB block domains with increase in sulfonation of PS blocks were investigated semi-quantitatively using tapping mode atomic force

  2. Tissue engineering of fish skin: behavior of fish cells on poly(ethylene glycol terephthalate)/poly(butylene terephthalate) copolymers in relation to the composition of the polymer substrate as an initial step in constructing a robotic/living tissue hybrid.

    Science.gov (United States)

    Pouliot, Roxane; Azhari, Rosa; Qanadilo, Hala F; Mahmood, Tahir A; Triantafyllou, Michael S; Langer, Robert

    2004-01-01

    This study presents the development of a biosynthetic fish skin to be used on aquatic robots that can emulate fish. Smoothness of the external surface is desired in improving high propulsive efficiency and maneuvering agility of autonomous underwater vehicles such as the RoboTuna (Triantafyllou, M., and Triantafyllou, G. Sci. Am. 272, 64, 1995). An initial step was to determine the seeding density and select a polymer for the scaffolds. The attachment and proliferation of chinook salmon embryo (CHSE-214) and brown bullhead (BB) cells were studied on different compositions of a poly(ethylene glycol terephthalate) (PEGT) and poly(butylene terephthalate) (PBT) copolymer (Polyactive). Polymer films were used, cast of three different compositions of PEGT/PBT (weight ratios of 55/45, 60/40, and 70/30) and two different molecular masses of PEGT (300 and 1000 Da). When a 55 wt% and a 300-Da molecular mass form of PEGT was used, maximum attachment and proliferation of CHSE-214 and BB cells were achieved. Histological studies and immunostaining indicate the presence of collagen and cytokeratins in the extracellular matrix formed after 14 days of culture. Porous scaffolds of PEGT/PBT copolymers were also used for three-dimensional tissue engineering of fish skin, using BB cells. Overall, our results indicate that fish cells can attach, proliferate, and express fish skin components on dense and porous Polyactive scaffolds.

  3. Hidrofilicidade de filmes de amido/poli(butileno adipato co-tereftalato (Pbat adicionados de tween 80 e óleo de soja Hydrophilicity of starch and poly(butylene adipate-co-terephthalate (Pbat films containing tween 80 and soybean oil

    Directory of Open Access Journals (Sweden)

    Renata P. Herrera Brandelero

    2013-01-01

    Full Text Available A incorporação de amido ao polímero poli (butilenoadipatoco-tereftalato (PBAT através de blendas com alto teor de amido pode ser uma alternativa para obter embalagens biodegradáveis, minimizar custos e o uso de recursos não renováveis. No entanto, a adição de amido aumenta a permeabilidade ao vapor de água (PVA. A incorporação em filmes com amido de substâncias como óleos vegetais e surfactantes pode diminuir a hidrofilicidade, favorecendo as aplicações destes como embalagens. A hidrofilicidade dos filmes elaborados por blendas de amido/PBAT adicionados de óleo de soja (OS e tween 80 (TW foi avaliada considerando o efeito do OS e TW nas isotermas de sorção dos filmes, na PVA e nos coeficientes de difusão (Dw e solubilidade (β do vapor de água. Filmes com OS com ou sem TW apresentaram menor quantidade de água de sorção, sendo os filmes com menores quantidades de OS e sem TW menos hidrofílicos e menos permeáveis aos vapores de água. A adição de OS reduziu os valores de β e Dw dos filmes de amido/PBAT. O efeito foi relacionado com o aumento das porções hidrofóbicas e da compatibilidade entre o amido e PBAT na presença de OS.Incorporating starch into the poly(butylene adipate-co-terephthalate (PBAT polymer by means of blends with high starch contents is a possible option for producing biodegradable packaging using renewable resources and reducing costs. However, the addition of starch increases the water vapour permeability (WVP. The incorporation of substances as lipids and surfactants can reduce the hydrophilicity of films containing starch, favouring their use as packaging. The hydrophilicity of films produced from blends of starch/PBAT with added soybean oil (SO and tween 80 (TW was studied. The effects of these substances on the sorption isotherm, on the WVP and on the water vapour diffusion (Dw and solubility (β coefficients of the films were evaluated. The water sorption in films with SO, with or without TW

  4. Aerogel Poly(butylene succinate) Biomaterial Substrate for RF and Microwave Applications

    Science.gov (United States)

    Habib Ullah, M.; Mahadi, W. N. L.; Latef, T. A.

    2015-01-01

    Polybutylene succinate (PBS) has become a potential candidate, similar to polypropylene (PP) and acrylonitrile butadiene styrene (ABS), for use as an organic plastic material due to its outstanding mechanical properties as well as high thermal deformation characteristics. A new composition of silica aerogel nanoparticles extracted from rice waste with PBS is proposed for use as a dielectric (εr = 4.5) substrate for microwave applications. A microstrip patch antenna was fabricated on the proposed dielectric substrate for multi-resonant ultra-wideband (UWB) applications. The performance characteristics of the proposed biomaterial-based antenna were investigated in a far-field measurement environment. The results indicate that the proposed biocompatible material-based antenna covered a bandwidth of 9.4 (2.3–11.7) GHz with stop bands from 5.5 GHz to 5.8 GHz and 7.0 GHz to 8.3 GHz. Peak gains of 9.82 dBi, 7.59 dBi, 8.0 dBi and 7.68 dBi were measured at resonant frequencies of 2.7 GHz, 4.6 GHz, 6.3 GHz and 9.5 GHz, respectively. PMID:26238975

  5. Study of the thermal properties of Acrylonitrile Butadiene Styrene - High Impact Polystyrene blends with Styrene Ethylene Butylene Styrene

    OpenAIRE

    PEYDRO Miguel Angel; JUAREZ David; Sanchez-Caballero, Samuel; PARRES Francisco

    2013-01-01

    A binary blend Acrylonitrile Butadiene Styrene ¿ High Impact Polystyrene (ABS-HIPS 50% wt) was prepared on a twin-screw extruder at 190-210 oC. The different properties were then analyzed using melt flow index (MFI), thermogravimetric analysis (TGA), and Fourier Transform Infrared spectroscopy (FTIR). FTIR analysis indicated heterogeneous distribution of the blend in injected pieces and SEM micrographs show heterogeneous distribution of both phase (ABS and HIPS). On the other hand, we have pr...

  6. Effect of nanoclay loading on the thermal and mechanical properties of biodegradable Polylactide/Poly[(butylene succinate)- co-adipate] blend composites

    CSIR Research Space (South Africa)

    Ojijo, Vincent O

    2012-04-01

    Full Text Available to 9%. Small angle X-ray scattering patterns showed slightly better dispersion in PBSA than PLA, and there was a tendency of the silicate layers to delaminate in PBSA at low clay content. Thermal analysis revealed that crystallinity was dependent...

  7. Effect of Hydroxyapatite Nanoparticles on the Degradability of Random Poly(butylene terephthalate-co-aliphatic dicarboxylates Having a High Content of Terephthalic Units

    Directory of Open Access Journals (Sweden)

    Nina Heidarzadeh

    2016-07-01

    Full Text Available Copolyesters derived from 1,4-butanediol and constituted also of aliphatic and aromatic dicarboxylate units in a molar ratio of 3:7 were synthesized by a two-step polycondensation procedure. Succinic, adipic, and sebacic acids were specifically selected as the aliphatic component whereas terephthalic acid was chosen as the aromatic moiety. The second synthesis step was a thermal transesterification between the corresponding homopolymers, always attaining a random distribution as verified by NMR spectroscopy. Hybrid polymer composites containing 2.5 wt % of hydroxyapatite (HAp were also prepared by in situ polymerization. Hydroxyl groups on the nanoparticle surface allowed the grafting of polymer chains in such a way that composites were mostly insoluble in the typical solvents of the parent copolyesters. HAp had some influence on crystallization from the melt, thermal stability, and mechanical properties. HAp also improved the biocompatibility of samples due to the presence of Ca2+ cations and the damping effect of phosphate groups. Interestingly, HAp resulted in a significant increase in the hydrophilicity of samples, which considerably affected both enzymatic and hydrolytic degradability. Slight differences were also found in the function of the dicarboxylic component, as the lowest degradation rates was found for the sample constituted of the most hydrophobic sebacic acid units.

  8. Role of special interfacial area in controlling properties of immiscible blends of biodegradable polylactide and poly[(butylene succinate)-co-adipate

    CSIR Research Space (South Africa)

    Ojijo, Vincent O

    2012-12-01

    Full Text Available stream_source_info Ojijo_2012_ABSTRACT ONLY.pdf.txt stream_content_type text/plain stream_size 1661 Content-Encoding ISO-8859-1 stream_name Ojijo_2012_ABSTRACT ONLY.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ACS...

  9. Enhanced bone marrow stromal cell adhesion and growth on segmented poly(ether ester)s based on poly(ethylene oxide) and poly(butylene terephthalate)

    NARCIS (Netherlands)

    Claase, M.B.; Olde riekerink, M.B.; de Bruijn, Joost Dick; Grijpma, Dirk W.; Engbers, G.H.M.; Feijen, Jan

    2003-01-01

    In previous studies in rats and goats, hydrophilic compositions of the PEOT/PBT block copolymer family have shown in vivo calcification and bone bonding. These copolymers are therefore interesting candidates as scaffolding materials in bone tissue engineering applications. Model studies using goat

  10. Surface modification of poly (styrene-b-(ethylene-co-butylene)-b-styrene) elastomer and its plasma protein adsorption by QCM-D

    Energy Technology Data Exchange (ETDEWEB)

    Li, Rui [Northeast Normal University, School of Physics, Changchun 130022 (China); Jin, Jing, E-mail: jjin@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Sun, Yingchun, E-mail: sunyc149@nenu.edu.cn [Northeast Normal University, School of Physics, Changchun 130022 (China)

    2014-05-01

    Graphical abstract: - Highlights: • Grafting concentration of PEG was defined by the peak-area ratio of [C–O]/[C]. • Quantitatively investigated the adsorption processes of BSA and fibrinogen using QCM-D. • The inactivated BSA on SEBS surface could induce the subsequent fibrinogen adsorption. • SEBS-g-PEG with graft concentration of 0.207 has excellent protein resistance. - Abstract: Protein adsorption is a dynamic process and plays a major role in determining the hemocompatibility of biomaterials. We have obtained different poly (ethylene glycol) (PEG) graft concentrations of SEBS-g-PEG and the surface chemical compositions are confirmed by X-ray photoelectron spectroscopy (XPS). Graft concentration is defined by peak-area ratio of [C-O]/[C] on modified SEBS surface. With increasing graft concentration, water contact angles of the modified SEBS have significantly decreased. The platelet adhesion and static protein adsorption demonstrate that the hemocompatibility of copolymers films are improved effectively and SEBS-g-PEG-2 with larger graft concentration has more superior anticoagulation than that of SEBS-g-PEG-1. Moreover, we have quantitatively investigated the adsorption process of bovine serum albumin (BSA) and fibrinogen (Fib) on the surfaces of pristine SEBS and modified SEBS using quartz crystal microbalance with dissipation (QCM-D) in real time. The results indicate that the inactivated BSA on the pristine SEBS can continuously induce the subsequent Fib adsorption. The hemocompatibility of SEBS-g-PEG-2 with the graft concentration of 0.207 has excellent anti-protein property and the bio-inert BSA layer on the film can resist the subsequent Fib adsorption.

  11. Reduction of protein adsorption to a solid surface by a coating composed of polymeric micelles with a glass-like core

    NARCIS (Netherlands)

    Hofs, B.; Brzozowska, A.; de Keizer, A.; Norde, W.; Stuart, Martien A. Cohen

    2008-01-01

    Adsorption studies by optical reflectometry show that complex coacervate core micelles (C3Ms) composed of poly([4-(2-amino-ethylthio)-butylene]hydrochloride)(49)-block-poly(ethylene oxide)(212) and poly([4-(2carboxy-ethylthio)-butylene] sodium salt)(47)-block-poly(ethylene oxide)(212) adsorb in

  12. Reduction of protein adsorption to a solid surface by a coating composed of polymeric micelles with a glass-like core

    NARCIS (Netherlands)

    Hofs, P.S.; Brzozowska, A.M.; Keizer, de A.; Norde, W.; Cohen Stuart, M.A.

    2008-01-01

    Adsorption studies by optical reflectometry show that complex coacervate core micelles (C3Ms) composed of poly([4-(2-amino-ethylthio)-butylene] hydrochloride)49-block-poly(ethylene oxide)212 and poly([4-(2-carboxy-ethylthio)-butylene] sodium salt)47-block-poly(ethylene oxide)212 adsorb in equal

  13. Irreversible structural transitions in mixed micelles of oppositely charged diblock copolymers in aqueous solution

    NARCIS (Netherlands)

    Voets, I.K.; Keizer, de A.; Cohen Stuart, M.A.; Justynska, J.; Schlaad, H.

    2007-01-01

    Using light scattering (titration) measurements, we have shown that micelles can be formed in aqueous solutions of a mixture of poly(4-(2-amino hydrochloride-ethylthio)butylene)-block-poly(ethylene oxide), PAETB(49)-b-PEO212, and poly(4-(2-sodium carboxylate-ethylthio)butylene)-block-poly(ethylene

  14. Unique morphology of dispersed clay particles in a polymer nanocomposite

    CSIR Research Space (South Africa)

    Malwela, T

    2011-02-01

    Full Text Available This communication reports a unique morphology of dispersed clay particles in a polymer nanocomposite. A nanocomposite of poly[butylene succinate)-co-adipate] (PBSA) with 3 wt% of organically modified montmorillonite was prepared by melt...

  15. Investigating the crystal growth behavior of biodegradable polymer blend thin films using in situ atomic force microscopy

    CSIR Research Space (South Africa)

    Malwela, T

    2014-01-01

    Full Text Available This article reports the crystal growth behavior of biodegradable polylactide (PLA)/poly[(butylene succinate)-co-adipate] (PBSA) blend thin films using atomic force microscopy (AFM). Currently, polymer thin films have received increased research...

  16. Effect of uncoated calcium carbonate and stearic acid coated ...

    Indian Academy of Sciences (India)

    Administrator

    butylene terephthalate) (PBT)/ ... Calcium carbonate particles, plain and coated with stearic acid, were kindly supplied by 20 MICRONS .... absorbed by the CaCO3 surface thus increasing the tem- perature of the point of maximum degradation ...

  17. Metal cleaner poisoning

    Science.gov (United States)

    Metal cleaners are very strong chemical products that contain acids. This article discusses poisoning from swallowing or ... Metal cleaners contain organic compounds called hydrocarbons, including: 1,2-butylene oxide Boric acid Cocoyl sarcosine Dicarboxylic ...

  18. Microspheres for protein delivery prepared from amphiphilic multiblock copolymers. 1. influence of preparation techniques on particle characteristics and protein delivery

    NARCIS (Netherlands)

    Bezemer, J.M.; Radersma, R.; Grijpma, Dirk W.; Dijkstra, Pieter J.; van Blitterswijk, Clemens; Feijen, Jan

    2000-01-01

    The entrapment of lysozyme in amphiphilic multiblock copolymer microspheres by emulsification and subsequent solvent removal processes was studied. The copolymers are composed of hydrophilic poly(ethylene glycol) (PEG) blocks and hydrophobic poly(butylene terephthalate) (PBT) blocks. Direct solvent

  19. Proceedings of International Wire and Cable Symposium (24th), Held at Cherry Hill, New Jersey, on November 18, 19 and 20, 1975

    Science.gov (United States)

    1975-11-01

    Isopropyl Triisostearoyl Titanate Isopropyl Tri (Lauryl-Myristyl) Titanate Isopropyl Isostearoyl, Dimethacryl Titanate TB2NS-26 TTM-33 TSN2C...polystyrene agregates referred to as domains. These domains are dispersed in a contin- uous rubber matrix of ethylene- butylene polymer...Each individual S-EB-S molecule has its chain ends in a polystyrene domain and its center segment in the con- tinuous poly(ethylene- butylene

  20. Analise térmica e microscópica de laminados biodegradáveis obtidos a partir de farinha de mandioca, sorbitol e poli (butileno adipato co-tereftalato PBAT. Thermal and microscopic analysis of biodegradable laminates made from cassava flour, sorbitol and poly (butylene adipate-co-terephthalate PBAT - doi: 10.4025/actascitechnol.v35i4.13183

    Directory of Open Access Journals (Sweden)

    Henrique Tirolli Rett

    2013-10-01

    Full Text Available O objetivo deste trabalho foi desenvolver blendas de materiais laminados biodegradáveis, utilizando farinha de mandioca como fonte de amido, fibras naturais, sorbitol como plastificante e PBAT. Primeiro obteve-se peletes de três formulações diferentes e a partir destes, utilizou-se a termoprensagem a alta temperatura como alternativa na formação dos laminados. A caracterização foi feita através de microscopia eletrônica de varredura (MEV e calorimetria diferencia de varredura (CDV. A quantidade se sorbitol que melhor se ajustou à extrusão foi a de 15% (peso/peso; a formulação do laminado mais homogêneo, observada pela microscopia, foi de 55:40:15 (farinha/sorbitol/PBAT. As fibras ficaram dispersas por toda a superfície nos três tratamentos estudados, porém, por dentre eles, observaram-se zonas dispersas das fibras. Conforme se aumentou o teor de farinha, houve aumento no ponto de fusão dos laminados em comparação ao PBAT puro.Blends of biodegradable laminated materials were developed using cassava flour as starch and natural fibers source, sorbitol as a plasticizer and PBAT as a biodegradable polyester. After obtaining pellets from three different formulations, high temperature thermopressure was used to form laminates. The characterization was performed by scanning electron microscopy (SEM and by differential scanning calorimetry (DSC. The amount of sorbitol for the best extrusion process was 15% (weight/weight and the formulation of the best homogeneity observed by microscopy was 55:40:15 (flour/sorbitol/PBAT. Although fibers were dispersed throughout the surface in the three treatments, scattered areas of fibers could be found among them. As rates of flour increased, an increase in the melting point of the laminates occurred when compared to pure PBAT.  

  1. Biomineralization of Engineered Spider Silk Protein-Based Composite Materials for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    John G. Hardy

    2016-07-01

    Full Text Available Materials based on biodegradable polyesters, such as poly(butylene terephthalate (PBT or poly(butylene terephthalate-co-poly(alkylene glycol terephthalate (PBTAT, have potential application as pro-regenerative scaffolds for bone tissue engineering. Herein, the preparation of films composed of PBT or PBTAT and an engineered spider silk protein, (eADF4(C16, that displays multiple carboxylic acid moieties capable of binding calcium ions and facilitating their biomineralization with calcium carbonate or calcium phosphate is reported. Human mesenchymal stem cells cultured on films mineralized with calcium phosphate show enhanced levels of alkaline phosphatase activity suggesting that such composites have potential use for bone tissue engineering.

  2. Combination chemotherapy using core-shell nanoparticles through the self-assembly of HPMA-based copolymers and degradable polyester.

    Science.gov (United States)

    Jäger, Eliézer; Jäger, Alessandro; Chytil, Petr; Etrych, Tomáš; Ríhová, Blanka; Giacomelli, Fernando Carlos; Stěpánek, Petr; Ulbrich, Karel

    2013-01-28

    The preparation of core-shell polymeric nanoparticles simultaneously loaded with docetaxel (DTXL) and doxorubicin (DOX) is reported herein. The self-assembly of the aliphatic biodegradable copolyester PBS/PBDL (poly(butylene succinate-co-butylene dilinoleate)) and HPMA-based copolymers (N-(2-hydroxypropyl)methacrylamide-based copolymers) hydrophobically modified by the incorporation of cholesterol led to the formation of narrow-size-distributed (PDIHPMA copolymer on the particle surface for simultaneous passive and active targeting and different combination therapies. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Processing of poly(hydroxybutyrate-co-hydroxyvalerate)-based bionanocomposite foams using supercritical fluids

    Science.gov (United States)

    Alireza Javadi; Yottha Srithep; Craig C. Clemons; L-S. Turng; Shaoqin. Gong

    2012-01-01

    Supercritical fluid (SCF) N2 was used as a physical foaming agent to fabricate microcellular injection-molded poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)–poly(butylene adipate-co-terephthalate) (PBAT)–hyperbranched-polymer (HBP)–nanoclay (NC) bionanocomposites. The effects of incorporating HBP and NC on the morphological, mechanical, and...

  4. Phase structure and properties of poly(ethylene terephthalate)/polyethylene based on recycled materials

    Science.gov (United States)

    Yong Lei; Qinglin Wu; Craig M. Clemons; Weihong. Guo

    2009-01-01

    Blends based on recycled high density polyethylene (R-HDPE) and recycled poly(ethylene terephthalate) (R-PET) were made through reactive extrusion. The effects of maleated polyethylene (PE-g-MA), triblock copolymer of styrene and ethylene/butylene (SEBS), and 4,40-methylenedi(phenyl isocyanate) (MDI) on blend properties were studied. The 2% PE-g-MA improved the...

  5. Study of morphology and crystal growth behaviour of nanoclay-containing biodegradable polymer blend thin films using atomic force microscopy

    CSIR Research Space (South Africa)

    Malwela, T

    2012-04-01

    Full Text Available Thin films of unmodified and nanoclay-modified polylactide/poly(butylene succinate) (PLA/PBS) blends were prepared on a glass substrate with a spin coater. The morphology and crystal growth behaviours for the films, crystallized at different...

  6. Structure–property relationship of specialty elastomer–clay ...

    Indian Academy of Sciences (India)

    The present work deals with the synthesis of specialty elastomer [fluoroelastomer and poly (styrene--ethylene-co-butylene--styrene (SEBS)]–clay nanocomposites and their structure–property relationship as elucidated from morphology studies by atomic force microscopy, transmission electron microscopy and X-ray ...

  7. Control of protein delivery from amphiphilic poly(ether ester) multiblock copolymers by varying their water content using emulsification techniques

    NARCIS (Netherlands)

    Bezemer, J.M.; Grijpma, Dirk W.; Dijkstra, Pieter J.; van Blitterswijk, Clemens; Feijen, Jan

    2000-01-01

    Protein-containing films and microspheres, based on poly(ethylene glycol)–poly(butylene terephthalate) (PEG–PBT) multiblock copolymers, were prepared from water-in-oil (w/o) emulsions. The properties of the matrices could be controlled by the water-to-polymer ratio (w/p) in the w/o emulsion. A

  8. CO2-selective PEO–PBT (PolyActive™)/graphene oxide composite membranes

    KAUST Repository

    Karunakaran, Madhavan

    2015-07-31

    CO2-selective graphene oxide (GO) nano-composite membranes were prepared for the first time by embedding GO into a commercially available poly(ethylene oxide)–poly(butylene terephthalate) (PEO–PBT) copolymer (PolyActive™). The as-prepared GO membrane shows high CO2 permeability (143 Barrer) and CO2/N2 selectivity (α = 73).

  9. PEOT/PBT based scaffolds with low mechanical properties improve cartilage repair tissue formation in osteochondral defects

    NARCIS (Netherlands)

    Jansen, Edwin J. P.; Pieper, Jeroen; Gijbels, Marion J. J.; Guldemond, Nick A.; Riesle, Jens; Van Rhijn, Lodewijk W.; Bulstra, Sjoerd K.; Kuijer, Roel

    The aim of our Study was to compare the healing response of biomechanically and biochemically different scaffolds in osteochondral defects created in rabbit medial femoral condyles. A block copolymer comprised of poly(ethylene oxide terephthalate) and poly(butylene terephthalate) was used to prepare

  10. Are reactive thermoplastic polymers suitable for future wind turbine composite materials blades?

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran

    2014-01-01

    , it was found that only two potential reactive thermoplastic resin systems qualify for different processing requirements for blade manufacturing. Hence, the article focuses on the issues with the use of reactive polymers like APA-6 (Caprolactam) and CBT (Cyclic Butylene Terephtalate) resin systems for composite...

  11. Direct production of lower olefins from synthesis gas using supported iron catalysts

    NARCIS (Netherlands)

    Torres Galvis, H.M.

    2013-01-01

    Lower olefins (ethylene, propylene and butylenes) are important commodity chemicals used for the manufacture of, amongst others, plastics, solvents and lubricants to cosmetics and drugs. C2 to C4 olefins are conventionally produced by steam cracking of naphtha. In view of economic, strategic, and

  12. Nano-apatite/polymer composites: mechanical and physicochemical characteristics

    NARCIS (Netherlands)

    Liu, Qing; de Wijn, J.R.; van Blitterswijk, Clemens

    1997-01-01

    Hydrothermally synthesized acicular nano-apatite (Nap) was used as filler to make composites with a polyethylene glycol/poly(butylene terephthalate) (PEG/PBT) block copolymer (Polyactive™70:30). The Nap had a particle diameter of 9–25 nm and a length of 80–200 nm. The mechanical properties and the

  13. Biodegradable composites from polyester and sugar beet pulp with antimicrobial coating for food packaging

    Science.gov (United States)

    Totally biodegradable, double-layered antimicrobial composite Sheets were introduced for food packaging. The substrate layers of the sheets were prepared from poly (lactic acid) (PLA) and sugar beet pulp (SBP) or poly (butylene adipate-co-terephthalate (PBAT) and SBP by a twin-screw extruder. The ac...

  14. Design of porous scaffolds for cartilage tissue engineering using a three-dimensional fiber-deposition technique

    NARCIS (Netherlands)

    Woodfield, T.B.F.; Malda, J.; de Wijn, J.; Peters, F.; Riesle, J.U.; van Blitterswijk, Clemens

    2004-01-01

    In this study, we present and characterize a fiber deposition technique for producing three-dimensional poly(ethylene glycol)-terephthalate—poly(butylene terephthalate) (PEGT/PBT) block co-polymer scaffolds with a 100% interconnecting pore network for engineering of articular cartilage. The

  15. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    J D Ekhe. Articles written in Bulletin of Materials Science. Volume 33 Issue 3 June 2010 pp 277-284 Composites. Effect of uncoated calcium carbonate and stearic acid coated calcium carbonate on mechanical, thermal and structural properties of poly(butylene terephthalate) (PBT)/calcium carbonate composites.

  16. In vitro degradation of polyactive® 1000PEOT70PBT30 devices

    NARCIS (Netherlands)

    Kellomäki, M.; Paasimaa, S.; Grijpma, Dirk W.; Kolppo, K.; Törmälä, P.

    2002-01-01

    Polyactive® 1000PEOT70PBT30 (a segmented block copolymer of poly(ethylene oxide terephtalate)/poly(butylene terephtalate) with 70/30 PEOT/PBT ratio) was processed into three different types of samples: injection molded to rods, hot-pressed to films and to composite membranes made by hot-pressing a

  17. Processing and characterization of solid and microcellular PHBV/PBAT blend and its RWF/nanoclay composites

    Science.gov (United States)

    Alireza Javadi; Yottha Srithep; Jungjoo Lee; Srikanth Pilla; Craig Clemons; Shaoqin Gong; Lih-Sheng Turng

    2010-01-01

    Solid and microcellular components made of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/ poly (butylenes adipate-co-terephthalate) (PBAT) blend (weight ration of PHBV:PBAT = 30:70), recycled wood fiber (RWF), and nanoclay (NC) were prepared via a conventional and microcellular-injection molding process, respectively. Morphology, thermal properties, and...

  18. Biological resistance of polyethylene composites made with chemically modified fiber or flour

    Science.gov (United States)

    Rebecca E. Ibach; Craig M. Clemons

    2002-01-01

    The role of moisture in the biological decay of wood-plastic composites was investigated. Southern pine wood fiber and ponderosa pine wood flour were chemically modified using either acetic anhydride (AA), butylene oxide (BO), or propylene oxide (PO). A 50:50 mixture of high density polyethylene and either chemically modified fiber or flour, or untreated fiber or flour...

  19. International Traffic in Arms Regulations (ITAR), (22 CFR 120-130)

    Science.gov (United States)

    1996-06-01

    chlathrates of CL- 20); (30) Polynitrocubanes with more than four nitro groups; (31) Ammonium dinitramide ( ADN or SR-12); (32) Cyclotrimethylentrinitramine...Nitratomethylmethyloxetane or poly (3-nitratomethyl, 3- methyl oxetane); (Poly- NIMMO); (NMMO); (13) Azidomethylmethyloxetane (AMMO) and its polymers; (14...isophthalic, trimesic BITA or butylene imine tri- mesamide isoyanuric, or trimethyladipic back- bone structures and 2- methyl or 2-ethyl substitutions on

  20. Gas plasma etching of PEO/PBT segmented block copolymer films

    NARCIS (Netherlands)

    Olde riekerink, M.B.; Claase, M.B.; Engbers, G.H.M.; Grijpma, Dirk W.; Feijen, Jan

    2003-01-01

    A series of poly(ethylene oxide)/poly(butylene terephthalate) (PEO/PBT) segmented block copolymer films was treated with a radio-frequency carbon dioxide (CO2) or with argon (Ar) plasma. The effects of (preferential) etching on surface structure, topography, chemistry, and wettability were studied

  1. Marine Exposure of Preservative-Treated Small Wood Panels.

    Science.gov (United States)

    1984-10-01

    Chemical modification of panels with propylene oxide (table 5) has prevented . -. attack by Limnoria and teredines for 8 years. Panels treated with butylene ...exposure rating ɞ . -’ Pot Years -. Butylene oxide 123.7 12/77 10 5-1/2 6 󈧠.5 6/78 10 5 Propylene oxide 󈧚.1 6/75 10 8 26.6 6/75 10 8 󈧣.6 6/75 10 8... dimethacrylate 29.3 6/77 10 60 TBTM 35.0 6/77 10 6 27.0 12177 10 5-1/2 TBTM in mineral spirits 3.08 (polymer) 12J77 10 5-1/2 TBTMIGMA4 37.0 6/77 10 6

  2. Biodegradable Plastic-degrading Activity of Various Species of Paraphoma.

    Science.gov (United States)

    Koitabashi, Motoo; Sameshima-Yamashita, Yuka; Koike, Hideaki; Sato, Toyozo; Moriwaki, Jouji; Morita, Tomotake; Watanabe, Takashi; Yoshida, Shigenobu; Kitamoto, Hiroko

    2016-07-01

    The fungal strain B47-9, isolated from barley, was previously selected as an effective degrader of various biodegradable plastic (BP) films such as poly(butylene succinate-co-adipate) (PBSA) and poly(butylene succinate) (PBS). The strain has not been identified based on mycological methods because it does not form fruiting bodies, which are the key to morphological identification. Here, we performed molecular phylogenetic analyses of the nuclear ribosomal RNA gene regions and their internal transcribed spacer region of B47-9 and related fungi. The results suggest that B47-9 is closely related to the genus Paraphoma. Investigation of the abilities of six strains belonging to the genus Paraphoma to degrade BPs indicated that all strains could degrade PBSA and PBS films to varying degrees. Based on our approach, we conclude that strain B47-9 is a species belonging to the genus Paraphoma.

  3. Modification of Biodegradable Polyesters Using Electron Beam

    OpenAIRE

    M. Suhartini

    2013-01-01

    Poly(4-Hydroxybutirat) P4HB, Poly(butylene succinate-co-adipate) PBSA and Poly(-caprolactone) PCL were electron beam (EB)-irradiated. Poly(4-Hydroxybutirat) was irradiated without any polyfunctional monomers (PFM). While PBSA and PCL were irradiated in the presence of polyfunctional monomers such as Trimethallyl isocyanurate (TMAIC), Polyethyleneglycol dimethacrylate (2G, 4G), Trimethylolpropane trimethacrylate (TMPT) and Tetramethylolmethane tetraacrylate (A-TMMT) at ambient temperature. Ai...

  4. Modification of Biodegradable Polyesters Using Electron Beam

    OpenAIRE

    M. Suhartini

    2013-01-01

    Poly(4-Hydroxybutirat)p4hb, Poly(butylene succinate-co-adipate) PBSA and Poly(e-caprolactone) PCL were electron beam (EB)-irradiated. Poly(4-Hydroxybutirat) was irradiated without any polyfunctional monomers (PFM). While PBSA and PCL were irradiated in the presence of polyfunctional monomers such asTrimethallyl isocyanurate (TMAIC), Polyethyleneglycol dimethacrylate (2G, 4G), Trimethylolpropane trimethacrylate (TMPT) and Tetramethylolmethane tetraacrylate (A-TMMT) at ambient temperature. Ai...

  5. 49 CFR 173.313 - UN Portable Tank Table for Liquefied Compressed Gases.

    Science.gov (United States)

    2010-10-01

    ... Normal 0.51 7.0 7.0 7.0 1012 Butylene 8.0 Allowed Normal 0.53 7.0 7.0 7.0 1017 Chlorine 19.0 Not § 178... Vinyl bromide, stabilized 7.0 Allowed Normal 1.37 7.0 7.0 7.0 1086 Vinyl chloride, stabilized 10.6...

  6. 3D-Printed Millimeter Wave Structures

    Science.gov (United States)

    2016-03-14

    demonstrates the resolution of the printer with a 10 micron nozzle. Figure 2: Measured loss tangent of SEBS and SBS samples. 3D - Printed Millimeter... 3D printing of styrene-butadiene-styrene (SBS) and styrene ethylene/butylene-styrene (SEBS) is used to demonstrate the feasibility of 3D - printed ...Additionally, a dielectric lens is printed which improves the antenna gain of an open-ended WR-28 waveguide from 7 to 8.5 dBi. Keywords: 3D printing

  7. Isolation and characterization of Arctic microorganisms decomposing bioplastics

    OpenAIRE

    Urbanek, Aneta K.; Rymowicz, Waldemar; Strzelecki, Mateusz C.; Kociuba, Waldemar; Franczak, ?ukasz; Miro?czuk, Aleksandra M.

    2017-01-01

    The increasing amount of plastic waste causes significant environmental pollution. In this study, screening of Arctic microorganisms which are able to degrade bioplastics was performed. In total, 313 microorganisms were isolated from 52 soil samples from the Arctic region (Spitsbergen). Among the isolated microorganisms, 121 (38.66%) showed biodegradation activity. The ability of clear zone formation on emulsified poly(butylene succinate-co-adipate) (PBSA) was observed for 116 microorganisms ...

  8. Polypropylene/organoclay/SEBS nanocomposites with toughness-stiffness properties

    DEFF Research Database (Denmark)

    Sanporean (nee Potarniche), Catalina-Gabriela; Vuluga, Zina; Radovici, Constantin

    2014-01-01

    Polypropylene nanocomposites with a different amount of styrene-ethylene-butylene-styrene block copolymer (SEBS)/clay were prepared via a melt mixing technique. To improve the dispersion of commercial organoclay (denoted as OMMT), various amounts of SEBS were incorporated. At a fixed content...... of OMMT, the mechanical properties were improved with increasing SEBS content. The obtained nanocomposites were characterized through X-ray diffraction (XRD), differential scanning calorimetry (DSC-TG) and mechanical tests. The thermal-morphological-mechanical properties were investigated...

  9. Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

    OpenAIRE

    J. B. Olivato; Grossmann, M. V. E.; Bilck, A. P.; Yamashita, F.; DE OLIVEIRA, L M

    2013-01-01

    Blends of starch/polyester have been of great interest in the development of biodegradable packaging. A method based on multiple responses optimisation (Desirability) was used to evaluate the properties of tensile strength, perforation force, elongation and seal strength of cassava starch/poly(butylene adipate-co-terephthalate) (PBAT) blown films produced via a one-step reactive extrusion using tartaric acid (TA) as a compatibiliser. Maximum results for all the properties were set as more des...

  10. Degradation of biodegradable plastic mulch films in soil environment by phylloplane fungi isolated from gramineous plants.

    Science.gov (United States)

    Koitabashi, Motoo; Noguchi, Masako T; Sameshima-Yamashita, Yuka; Hiradate, Syuntaro; Suzuki, Ken; Yoshida, Shigenobu; Watanabe, Takashi; Shinozaki, Yukiko; Tsushima, Seiya; Kitamoto, Hiroko K

    2012-08-02

    To improve the biodegradation of biodegradable plastic (BP) mulch films, 1227 fungal strains were isolated from plant surface (phylloplane) and evaluated for BP-degrading ability. Among them, B47-9 a strain isolated from the leaf surface of barley showed the strongest ability to degrade poly-(butylene succinate-co-butylene adipate) (PBSA) and poly-(butylene succinate) (PBS) films. The strain grew on the surface of soil-mounted BP films, produced breaks along the direction of hyphal growth indicated that it secreted a BP-degrading enzyme, and has directly contributing to accelerating the degradation of film. Treatment with the culture filtrate decomposed 91.2 wt%, 23.7 wt%, and 14.6 wt% of PBSA, PBS, and commercially available BP polymer blended mulch film, respectively, on unsterlized soil within 6 days. The PCR-DGGE analysis of the transition of soil microbial community during film degradation revealed that the process was accompanied with drastic changes in the population of soil fungi and Acantamoeba spp., as well as the growth of inoculated strain B47-9. It has a potential for application in the development of an effective method for accelerating degradation of used plastics under actual field conditions.

  11. Synthesis of thermoplastic poly(ester-olefin elastomers

    Directory of Open Access Journals (Sweden)

    Tanasijević Branka

    2004-01-01

    Full Text Available A series of thermoplastic poly(ester-olefin elastomers, based on poly(ethylene-stat-butylene, HO-PEB-OH, as the soft segment and poly (butylene terephthalate, PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene segments into the copolyester backbone was accomplished by the polycondensation of α, ω-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol with 1,4-butanediol (BD and dimethyl terephthalate (DMT in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu4, and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD, as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu4 for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylenes were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefins were investigated by differential scanning calorimetry (DSC. The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA. The rheological properties of poly(ester-olefins were investigated by dynamic mechanical spectroscopy in the melt and solid state.

  12. Morphology and properties of nanocomposites based on polymer blend and organoclay

    CSIR Research Space (South Africa)

    Gcwabaza, T

    2008-10-01

    Full Text Available commercial product from Sigma- Aldrich with molecular weight Mw = 174k g/mol and a melting point of 165 oC. Poly(1,4-butylene succinate) (PBS) used in this study is a commercial product from Sigma- Aldrich with melting point of 120°C. According... min and then cool down to room temperature. Characterization The freeze-fractured surface morphologies of pure blend and nanocomposite were investigated by scanning electron microscopy (SEM) (LEO 1525 FE-SEM), operated at an acceleration...

  13. Refining of Military Jet Fuels from Shale Oil. Part IV. Process Computer Modeling Studies.

    Science.gov (United States)

    1982-08-01

    Thermal Units C1 Methane C2 Ethane C3 Propane C3 Propylene C4 Mixed Butanes n-C4 Normal Butane i-C4 Isobutane C4 " Butylene C5 Pentane C6...for lighter products such as fuel gas, propane , propylene, C4 ’s, and C5 1 s. For heavier stream components, a set of pseudocomponents was developed...yields rapidly rise in the crack- ing unit as hydrotreating severity in the crude shale hydro- treater is reduced. This phenomenon results in the

  14. Composites structures for bone tissue reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Neto, W.; Santos, João [Universidade Federal de São Carlos, Departament of Materials Engineering - Rd. Washington Luis, Km 235, 13565-905, São Carlos-SP (Brazil); Avérous, L.; Schlatter, G.; Bretas, Rosario, E-mail: bretas@ufscar.br [Université de Strasbourg, ECPM-LIPHT - 25 rue Becquerel, 67087, Strasbourg (France)

    2015-05-22

    The search for new biomaterials in the bone reconstitution field is growing continuously as humane life expectation and bone fractures increase. For this purpose, composite materials with biodegradable polymers and hydroxyapatite (HA) have been used. A composite material formed by a film, nanofibers and HA has been made. Both, the films and the non-woven mats of nanofibers were formed by nanocomposites made of butylene adipate-co-terephthalate (PBAT) and HA. The techniques used to produce the films and nanofibers were spin coating and electrospinning, respectively. The composite production and morphology were evaluated. The composite showed an adequate morphology and fibers size to be used as scaffold for cell growth.

  15. Influence of ECR-RF plasma modification on surface and thermal properties of polyester copolymer

    Directory of Open Access Journals (Sweden)

    Fray Miroslawa El

    2015-12-01

    Full Text Available In this paper we report a study on influence of radio-frequency (RF plasma induced with electron cyclotron resonance (ECR on multiblock copolymer containing butylene terephthalate hard segments (PBT and butylene dilinoleate (BDLA soft segments. The changes in thermal properties were studied by DSC. The changes in wettability of PBT-BDLA surfaces were studied by water contact angle (WCA. We found that ECR-RF plasma surface treatment for 60 s led to decrease of WCA, while prolonged exposure of plasma led to increase of WCA after N2 and N2O2 treatment up to 70°–80°. The O2 reduced the WCA to 50°–56°. IR measurements confirmed that the N2O2 plasma led to formation of polar groups. SEM investigations showed that plasma treatment led to minor surfaces changes. Collectively, plasma treatment, especially O2, induced surface hydrophilicity what could be beneficial for increased cell adhesion in future biomedical applications of these materials.

  16. The influence of chemical composition of aliphatic-aromatic copolyesters on their properties

    Energy Technology Data Exchange (ETDEWEB)

    Wojtczak, Malgorzata; Galeski, Andrzej; Piorkowska, Ewa [Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz (Poland); Dutkiewicz, Slawomir [Institute of Biopolymers and Chemical Fibres, Marii Sklodowskiej-Curie 19/27, 90-570 Lodz (Poland)

    2014-05-15

    The chain microstructure and properties of a series of aliphatic-aromatic copolyesters in a range of compositions from 10 to 100% of aromatic components were studied by examining melting and crystallization behaviors, dynamic mechanical response, morphology, wide- (WAXS) and small-angle X-ray scattering (SAXS), and tensile deformation. Chain microstructure was analyzed by {sup 1}H NMR. The results indicate that most of copolyesters used in this study have essentially random distribution of comonomers. Copolyesters with more than 30 mol% of aromatic part crystallize with a crystal structure characteristic for homopolymer poly(butylene terephthalate) (PBT). However, some of the reflections from crystal planes are shifted towards lower diffraction angles as compared to butylene terephthalate homoplymer. The phase transition temperatures decrease with increasing aliphatic content. By means of polarized light microscopy (PLM), small-angle light scattering (SALS) and SAXS, crystallization behavior of a selected aliphatic-aromatic copolyester was further explored. Selected copolyester crystallizes in the form of thin fibrous crystals, few nanometers thick, which is the main factor influencing the depression of its melting temperature.

  17. Decay kinetics of benzophenone triplets and corresponding free radicals in soft and rigid polymers studied by laser flash photolysis.

    Science.gov (United States)

    Levin, Peter P; Efremkin, Alexei F; Sultimova, Natalie B; Kasparov, Valery V; Khudyakov, Igor V

    2014-01-01

    The kinetics of transients formed under photoexcitation of benzophenone (B) dissolved in three different polymers was studied by ns laser flash photolysis. These polymers were the soft rubbers poly (ethylene-co-butylene) (EB), polystyrene block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) and hard polystyrene (PS). We monitored the decay kinetics of triplet state (3)B(*) and of ketyl radicals BH(●). We observed exponential decay of (3)B(*) and two-stage decay kinetics of BH(●) in EB. The first stage is a fast cage recombination of a radical pair (BH(●), radical of polymer R(●)). The second slow stage of BH(●) decay follows the second-order law with a relatively high rate constant, which corresponds to recombination of BH(●) in a homogeneous liquid with a viscosity of only ~0.1 P (about five times of 2-propanol viscosity). Application of a magnetic field (MF) of 0.2 T leads to deceleration of both stages of BH(●) decay in EB by approximately 20%. Decay kinetics of both transients were observed in SEBS. There was no MF effect on BH(●) decay in SEBS. We only observed (3)B(*) in PS. Decay kinetics of (3)B(*) in this case were described as polychromatic dispersive first-order kinetics. We discuss the effects of polymer structure on transient kinetics and the MF effect. © 2013 The American Society of Photobiology.

  18. Transition-Metal-Free Synthesis of 1,3-Butadiene-Containing π-Conjugated Polymers.

    Science.gov (United States)

    Cai, Xuediao; Liu, Yating; Lu, Tian; Yang, Rui; Luo, Chuxin; Zhang, Qi; Chai, Yonghai

    2016-12-01

    This work describes the synthesis of π-conjugated polymers possessing arylene and 1,3-butadiene alternating units in the main chain by the reaction of α,β-unsaturated ester/nitrile containing γ-H with aromatic/heteroaromatic aldehyde compound. By using 4-(4-formylphenyl)-2-butylene acid ethyl ester as a model monomer, the different polymerization conditions, including catalyst, catalyst amount, and solvent, are optimized. The polymerization of 4-(4-formylphenyl)-2-butylene acid ethyl ester is carried out by refluxing in ethanol for 72 h with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a catalyst to give a 1,3-butadiene-containing π-conjugated polymer, poly(phenylene-1,3-butadiene), in 84.3% yield with M¯n and M¯w/M¯n (PDI) estimated as 6172 and 1.65, respectively. Based on this new methodology, a series of π-conjugated polymers containing 1,3-butadiene units with different substituents are obtained in high yields. A possible mechanism is proposed for the polymerization through a six-membered ring transition state and then a 1,5-H shift intermediate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Enzyme-catalyzed synthesis of unsaturated aliphatic polyesters based on green monomers from renewable resources.

    Science.gov (United States)

    Jiang, Yi; Woortman, Albert J J; van Ekenstein, Gert O R Alberda; Loos, Katja

    2013-08-12

    Bio-based commercially available succinate, itaconate and 1,4-butanediol are enzymatically co-polymerized in solution via a two-stage method, using Candida antarctica Lipase B (CALB, in immobilized form as Novozyme® 435) as the biocatalyst. The chemical structures of the obtained products, poly(butylene succinate) (PBS) and poly(butylene succinate-co-itaconate) (PBSI), are confirmed by 1H- and 13C-NMR. The effects of the reaction conditions on the CALB-catalyzed synthesis of PBSI are fully investigated, and the optimal polymerization conditions are obtained. With the established method, PBSI with tunable compositions and satisfying reaction yields is produced. The 1H-NMR results confirm that carbon-carbon double bonds are well preserved in PBSI. The differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results indicate that the amount of itaconate in the co-polyesters has no obvious effects on the glass-transition temperature and the thermal stability of PBS and PBSI, but has significant effects on the melting temperature.

  20. Effects of Thermal and Solvent Aging on Breakdown Voltage of TPE, PBT/PET Alloy, and PBT Insulated Low Voltage Electric Wire

    Directory of Open Access Journals (Sweden)

    Eun-Soo Park

    2013-01-01

    Full Text Available Tests were performed to evaluate the effects of thermal and solvent aging on the mechanical and dielectric breakdown properties of four types of polyester resins, namely, the insulation layer of poly(butylene terephthalat (PBT- based thermoplastic elastomer (TPE, TPE1, poly(butylene 2,6-naphthalate-based TPE (TPE2, PBT/poly(ethylene terephthalate alloy (Alloy, and PBT extruded onto a copper conductor of low voltage electric wire. The tensile specimens used in this series were prepared from the same extruded resins. The prepared electric wires and tensile specimens were thermally aged in air and in toluene, xylene, TCB, and NMP. When Alloy and PBT were thermally aged in toluene, xylene and TCB at 120°C for 6 h, the tensile properties were significantly decreased compared to TPE1 and TPE2 at the same condition. The reduction of elongation at break of Alloy was more discernible than that of PBT. This result indicated that Alloy is more affected by thermal and solvent ageing. Among them, TPE2 showed the highest breakdown voltage (BDV, and it has also the highest BDV after thermal and solvent aging.

  1. Isocyanate toughened pCBT: Reactive blending and tensile properties

    Directory of Open Access Journals (Sweden)

    T. Abt

    2013-02-01

    Full Text Available Cyclic butylene terephthalate oligomers (CBT were reacted in a ring-opening polymerization with three types of isocyanates: a bifunctional aromatic type, a bifunctional aliphatic type and a polymeric aromatic isocyanate. All reactions took place in a batch mixer. The use of 0.5 to 1 wt% isocyanate led to a dramatic increase in elongation at break of polymerized cyclic butylene terephthalate (pCBT, from 8 to above 100%. The stiffness and strength of the modified pCBT, however, were found to slightly decrease. Proton nuclear magnetic resonance (NMR analysis shows that the formation of thermally stable amide groups is the dominant chain extension reaction mechanism. Gel content measurements suggest a linear structure for samples containing bifunctional isocyanates while pCBT modified with polyfunctional isocyanate exhibited some gel formation at higher isocyanate content. Melting and crystallization temperatures as well as degree of crystallinity were found to decrease with increasing isocyanate content. No phase separation was detected by scanning electron microscopy (SEM analysis. Moreover, a high degree of polymerization is deduced due to the absence of CBT oligomer crystals.

  2. Catalyst Activity Comparison of Alcohols over Zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Ramasamy, Karthikeyan K.; Wang, Yong

    2013-01-01

    Alcohol transformation to transportation fuel range hydrocarbon on HZSM-5 (SiO2 / Al2O3 = 30) catalyst was studied at 360oC and 300psig. Product distributions and catalyst life were compared using methanol, ethanol, 1-propanol or 1-butanol as a feed. The catalyst life for 1-propanol and 1-butanol was more than double compared to that for methanol and ethanol. For all the alcohols studied, the product distributions (classified to paraffin, olefin, napthene, aromatic and naphthalene compounds) varied with time on stream (TOS). At 24 hours TOS, liquid product from 1-propanol and 1-butanol transformation primarily contains higher olefin compounds. The alcohol transformation process to higher hydrocarbon involves a complex set of reaction pathways such as dehydration, oligomerization, dehydrocyclization, and hydrogenation. Compared to ethylene generated from methanol and ethanol, oligomerization of propylene and butylene has a lower activation energy and can readily take place on weaker acidic sites. On the other hand, dehydrocyclization of propylene and butylene to form the cyclic compounds requires the sits with stronger acid strength. Combination of the above mentioned reasons are the primary reasons for olefin rich product generated in the later stage of the time on stream and for the extended catalyst life time for 1 propanol and 1 butanol compared to methanol and ethanol conversion over HZSM-5.

  3. An artificial neural network model for the prediction of mechanical and barrier properties of biodegradable films.

    Science.gov (United States)

    Nobrega, Marcelo Medre; Bona, Evandro; Yamashita, Fabio

    2013-10-01

    Nowadays, the production of biodegradable starch-based films is of great interest because of the growing environmental concerns regarding pollution and the need to reduce dependence on the plastics industry. A broad view of the role of different components, added to starch-based films to improve their properties, is required to guide the future development. The self-organizing maps (SOMs) provide comparisons that initially were complicated due to the large volume of the data. Furthermore, the construction of a model capable of predicting the mechanical and barrier properties of these films will accelerate the development of films with improved characteristics. The water vapor permeability (WVP) analysis using the SOM algorithm showed that the presence of glycerol is very important for films with low amounts of poly (butylene adipate co-terephthalate) and confirms the role of the equilibrium relative humidity in the determination of WVP. Considering the mechanical properties, the SOM analysis emphasizes the important role of poly (butylene adipate co-terephthalate) in thermoplastic starch based films. The properties of biodegradable films were predicted and optimized by using a multilayer perceptron coupled with a genetic algorithm, presenting a great correlation between the experimental and theoretical values with a maximum error of 24%. To improve the response of the model and to ensure the compatibility of the components more information will be necessary. © 2013.

  4. Application of reactive siloxane prepolymers for the synthesis of thermoplastic poly(ester–siloxanes and poly(ester–ether–siloxanes

    Directory of Open Access Journals (Sweden)

    VESNA V. ANTIC

    2007-02-01

    Full Text Available Thermoplastic poly(ester–siloxanes (TPES and poly(ester–ether–siloxane s, (TPEES, based on poly(butylene terephthalate (PBT as the hard segment and different siloxane-prepolymers as the soft segments, were prepared. The TPES and TPEES were synthesized by catalyzed two-step transesterification from dimethyl terephthalate, (DMT, 1,4-butanediol, (BD and a siloxane-prepolymer. Incorporation of dicarboxypropyl- or disilanol-terminated poly(dimethylsiloxanes (PDMS into the polar poly(butylene terephthalate chains resulted in rather inhomogeneous TPES copolymers, which was a consequence of a prononuced phase separation of the polar and non-polar reactants during synthesis. Two concepts were employed to avoid or reduce phase separation: 1 the use of siloxane-containing triblock prepolymers with hydrophilic terminal blocks, such as ethylene oxide (EO, poly(propylene oxide (PPO or poly(caprolactone (PLC when the terminal blocks serve as a compatibilizer between the extremely non-polar PDMS and the polar DMT and BD, and 2 the use of a high-boiling solvent (1,2,4-trichlorobenzene during the first phase of the reaction. Homogeneity was significantly improved in the case of copolymers based on PCL–PDMS–PCL.

  5. Compatibility and Impact Resistance of Biodegradable Polymer Blends Using Clays and Natural Nanotubes

    Science.gov (United States)

    Guo, Yichen; Yuan, Xue; Zuo, Xianghao; Rafailovich, Miriam

    Montmorillonite clays and Halloysite nanotubes (HNTs) were modified by surface adsorption of resorcinol di (phenyl phosphate) (RDP) oligomers. Biodegradable poly (lactic acid) (PLA) and poly (butylene adipate-co-butylene terephthalate) (PBAT) polymers were blended together with RDP coated clays and tubes. TEM images of thin sections indicated that even though both RDP coated clay nanotubes and platelets located on the interfacial region between two immiscible polymers, only the platelets, having the larger aspect ratio, were able to reduce the PBAT domain sizes. The ability of clay platelets to partially compatibilize the blend was further confirmed by the dynamic mechanical analysis (DMA) which showed that the glass transition temperatures of two polymers tend to shift closer. Izod impact testing demonstrated that the rubbery PBAT phase greatly increased the impact strength of the unfilled blend, but addition of only 5% of clay filler decrease the impact strength by nearly 50% while a small increase was observed with nanotubes at that concentration. A simple model is proposed. The clay platelets are observed to cover the interfacial area. Although they are effective at reducing the interfacial tension, they block the entanglements between two polymer phase and increase the overall brittleness. On the other hand, the HNTs are observed to lie perpendicular to the interface, which makes them less effective in reducing interfacial tension, but far more effective at retarding micro-crack propagation.

  6. ABC triblock surface active block copolymer with grafted ethoxylated fluoroalkyl amphiphilic side chains for marine antifouling/fouling-release applications.

    Science.gov (United States)

    Weinman, Craig J; Finlay, John A; Park, Daewon; Paik, Marvin Y; Krishnan, Sitaraman; Sundaram, Harihara S; Dimitriou, Michael; Sohn, Karen E; Callow, Maureen E; Callow, James A; Handlin, Dale L; Willis, Carl L; Kramer, Edward J; Ober, Christopher K

    2009-10-20

    An amphiphilic triblock surface-active block copolymer (SABC) possessing ethoxylated fluoroalkyl side chains was synthesized through the chemical modification of a polystyrene-block-poly(ethylene-ran-butylene)-block-polyisoprene polymer precursor. Bilayer coatings on glass slides consisting of a thin layer of the amphiphilic SABC spray coated on a thick layer of a polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) thermoplastic elastomer were prepared for biofouling assays with the green alga Ulva and the diatom Navicula. Dynamic water contact angle analysis and X-ray photoelectron spectroscopy (XPS) were used to characterize the surfaces. Additionally, the effect of the Young's modulus of the coating on the release properties of sporelings (young plants) of the green alga Ulva was examined through the use of two different SEBS thermoplastic elastomers possessing modulus values of an order of magnitude in difference. The amphiphilic SABC was found to reduce the settlement density of zoospores of Ulva as well as the strength of attachment of sporelings. The attachment strength of the sporelings was further reduced for the amphiphilic SABC on the "low"-modulus SEBS base layer. The weaker adhesion of diatoms, relative to a PDMS standard, further highlights the antifouling potential of this amphiphilic triblock hybrid copolymer.

  7. Tetranuclear uranyl polyrotaxanes: preferred selectivity toward uranyl tetramer for stabilizing a flexible polyrotaxane chain exhibiting weakened supramolecular inclusion

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Lei; Wang, Lin; Zhao, Yu-liang; Shi, Wei-qun [Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Liu, Cai-ming [Beijing National Laboratory for Molecular Sciences, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences (China); Chai, Zhi-fang [Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); School of Radiological and Interdisciplinary Sciences and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou (China)

    2015-07-06

    Introduction of mechanically interlocked components into actinide-based metal-organic materials such as polyrotaxanes will generate an entirely new type of inorganic-organic hybrid materials showing more supramolecular encapsulation-based dynamics. In this work, tetranuclear uranyl-directed polyrotaxanes (UO{sub 2}){sub 4}O{sub 2}-C5A3-CB6 (1) and (UO{sub 2}){sub 4}O{sub 2}-C6A3-CB6 (2), which are the first actinide pseudorotaxanes with high-nuclearity uranium centers, were obtained through systematic extension of the string spacer in pseudorotaxane ligands from 1,4-butylene (C4) to 1,5-pentylene (C5) and 1,6-hexylene (C6). Both of the as-synthesized tetranuclear uranyl polyrotaxanes were structurally characterized and analyzed. Considering the structure of UO{sub 2}-C4A3-CB6 and the 1,4-butylene string spacer, the preference for the uranyl tetramer may be related to the configurational inversion of the pseudorotaxane ligands from trans mode to cis mode on coordination to the uranyl center. Detailed structural analysis suggests that the length of the stretched string molecules for CB6-encapsulated pseudorotaxanes has remarkable effect on the supramolecular inclusion interactions and the configurations of pseudorotaxanes, and should be responsible for the configurational inversion of pseudorotaxane spacers and subsequent distinct changes of the uranyl building units and geometric structures. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Characterization of Mode I Fracture and Morphological Properties of PLLA Blends with Addition of Lysine Triisocyanate

    Science.gov (United States)

    Vannaladsaysy, Vilay; Todo, Mitsugu

    Poly(L-lactic acid) (PLLA) was toughened by blending with three different ductile biopolymers such as poly (ε-caprolactone) (PCL), poly(butylene succinate-co-e-caprolactone) (PBSC), poly (butylene succinate-co-L-lactate) (PBSL). The blend ratio was fixed to 50:50. Lysine triisocyanate (LTI) was added to the blends as a compatibilizer. Characterizations such as Fourier transform infra-red (FT-IR) spectroscopy, field-emission electron microscope (FE-SEM), and mode I fracture test were used to characterize the effectiveness of LTI on the mechanical and morphological properties of various PLLA blends. It was found that PLLA/PCL blend shows the highest toughness energy among the binary blends. On the other hand, addition of LTI in PLLA/PBSC blend exhibits the best toughness property. Based on the FE-SEM observation, fractured surfaces of PLLA blends with LTI indicate ductile fracture with dense elongated fibrils. The largest damage zone is generated in the vicinity of crack-trip, suggesting that high energy dissipation occurred in the crack-trip region. FT-IR analysis also suggested that the NCO groups of LTI were acted as a compatibilizer, as the results of interaction between the two phases of the polymer blends.

  9. Bionanohybrid based on bioplastic and surface-functionalized carbon nanotubes.

    Science.gov (United States)

    Singh, Ravina; Ray, Suprakas Sinha

    2010-12-01

    A bionanohybrid consisting of biodegradable/biocompatible poly(butylene succinate) (PBS) and surface-oxidized carbon nanotubes (o-CNTs) was prepared via melt-mixing method. The inherent properties of PBS were concurrently improved by the incorporation of a small amount of o-CNTs. For example, at room temperature, elongation at break increased from approximately 21.2% for pure PBS to approximately 55.1% for the nanohybrid and an increase of about approximately 150% in the value of toughness with moderate improvement in tensile modulus and strength. The dynamic mechanical properties of PBS also increased significantly after nanocomposite formation with o-CNTs. Electron microscopy and Raman spectroscopy were used to investigate the mechanical properties and improvement mechanism of surface-functionalized o-CNTs containing PBS nanohybrid.

  10. Biodegradable polyester-based eco-composites containing hemp fibers modified with macrocyclic oligomers

    Science.gov (United States)

    Conzatti, Lucia; Utzeri, Roberto; Hodge, Philip; Stagnaro, Paola

    2016-05-01

    An original compatibilizing pathway for hemp fibers/poly(1,4-butylene adipate-co-terephtalate) (PBAT) eco-composites was explored exploiting the capability of macrocyclic oligomers (MCOs), obtained by cyclodepolymerization (CDP) of PBAT at high dilution, of being re-converted into linear chains by entropically-driven ring-opening polymerization (ED-ROP) that occurs simply heating the MCOS in the bulk. CDP reaction of PBAT was carried out varying solvent, catalyst and reaction time. Selected MCOs were used to adjust the conditions of the ED-ROP reaction. The best experimental conditions were then adopted to modify hemp fibers. Eco-composites based on PBAT and hemp fibers as obtained or modified with PBAT macrocyclics or oligomers were prepared by different process strategies. The best fiber-PBAT compatibility was observed when the fibers were modified with PBAT oligomers before incorporation in the polyester matrix.

  11. Syntheses of crosslinked latex nanoparticles using differential microemulsion polymerization

    Science.gov (United States)

    Hassmoro, N. F.; Rusop, M.; Abdullah, S.

    2013-06-01

    The differential microemulsion polymerization was used to synthesize latex nanoparticles. In this paper, 1, 3-butylene glycol dimethacrylate (1, 3-BGDMA) was used as a crosslinker respectively 1-5 weight% of monomer total. Butyl acrylate (BA), butyl methacrylate (BMA), and methacrylic acid (MAA) was used as the monomer. The thin film of latex nanoparticles were prepared by using spin coating method and have been dried at 100°C for 5 minutes. The amount of the crosslinker added in the polymerization was optimized and we found that the particle sizes fall in the range of 30-60 nm. The structural morphology of the uncrosslinked latex represented the most homogeneous image compared to the crosslinked latex. The effect of the amount of crosslinker on the particle sizes investigated by the Zeta-sizer Nano series while Atomic Force microscopy (AFM) was used to study the structural properties of latex nanoparticles.

  12. Zeolites Modified Metal Cations as Catalysts in Hydrocarbon Oxidation and the Alkyl Alcohol

    Directory of Open Access Journals (Sweden)

    Agadadsh Makhmud Aliyev

    2014-09-01

    Full Text Available The results of studies on the creation of highly metalltceolitnyh systems and the study of their catalytic activities in the oxidation of lower olefin hydrocarbons (ethylene to acetaldehyde, acetone, propylene, butylene methyl ethyl ketone; aliphatic C1-C5 alcohols to their corresponding aldehydes, ketones, carboxylic acids and carboxylic acid esters; oxidative dehydrogenation of naphthenes in the alicyclic diene hydrocarbons and the oxidative dimerization of methane to acetylene. It has been established that the selectivity of these catalysts determined optimal combination of metal components with the acidity and the structure of the zeolite. Selected highly effective catalysts for the reactions studied. Based on the results of experimental studies of the kinetics of the reactions of oxidation of lower olefin hydrocarbons and aliphatic alcohols, the oxidative dehydrogenation of naphthenes and oxidative coupling of methane on the synthesized catalysts are represented by their probable stepwise mechanism and kinetic models developed reactions.

  13. Lignin-based cement fluid loss control additive

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, P.

    1990-05-22

    This patent describes a hydraulic cement slurry composition. It comprises: a hydraulic cement, and the following expressed as parts by weight per 100 parts of the hydraulic cement, water from about 25 to 105 parts, and from abut 0.5 to 2.5 parts of a compound selected from the group consisting of a sulfonated lignin and a sulfomethylated lignin, wherein the lignin has been sequentially crosslinked by reacting the lignin with a member of the group consisting of formaldehyde and epichlorohydrin and alkoxylated with between about 2 to about 6 moles of a compound selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide and a combination thereof per 1000 g of the lignin.

  14. Tailor-Made Onion-Like Stereocomplex Crystals in Incompatible Enantiomeric Polylactide Containing Block Copolymer Blends

    Science.gov (United States)

    Zhu, Lei; Sun, Lu; Rong, Lixia; Hsiao, Benjamin

    2007-03-01

    Stereocomplexes formed by blending enantiomeric PLA block copolymers have demonstrated great potential for applications in biomedical devices. Here, we successfully synthesized well-defined enantiomeric PLA containing block copolymers by living ring-opening polymerization of L- and D-lactides from hydroxyl-terminated hydrophilic [poly(ethylene oxide) or PEO] and hydrophobic [poly(ethylene-co-1,2-butylene) or PEB] oligomers. Quantitative stereocomplex formation was achieved by equimolar mixing of the incompatible PEO-b-PLLA and PEB-b-PDLA. Intriguingly, in the blend of PEB-b-PDLA and PEO-b-PLLA with different PEB and PEO molecular weights, onion-like stereocomplex crystals were observed because of unbalanced surface stresses caused by different PEO and PEB molecular weights.

  15. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.

    2004-01-01

    The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order...... to evaluate the influence of the compatibility between gel and filler. Time-resolved SANS and small-angle X-ray scattering (SAXS) shows that the presence of silica particles affects the ordering of the polystyrene domains during gelsetting. The scattering pattern of silica-reinforced gels reveals strong...... scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from...

  16. Elaboration, morphology and properties of starch/polyester nano-biocomposites based on sepiolite clay.

    Science.gov (United States)

    Olivato, J B; Marini, J; Pollet, E; Yamashita, F; Grossmann, M V E; Avérous, L

    2015-03-15

    The incorporation of nano-sized sepiolite clays into thermoplastic starch/poly(butylene adipate-co-terephthalate) (TPS/PBAT) blends has been investigated with the goal of improving the matrix properties. TPS/PBAT nano-biocomposites were elaborated with two different proportions of the polymeric phases. The influence of the sepiolite nanoclays on the mechanical, thermal and structural properties of the corresponding blends was evaluated. SEM images confirmed the good dispersion of the sepiolite clay, with a low occurrence of small aggregates in the polymeric matrix. Wide-angle X-ray diffraction showed no significant alteration of the crystalline structures of PBAT and starch induced by the sepiolite clay. The addition of sepiolite slightly affected the thermal degradation of the nano-biocomposites; however, the mechanical tests revealed an increase in some mechanical properties, demonstrating that sepiolite is a promising nanofiller for TPS-based materials. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    2012-01-01

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  18. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  19. Mechanism of nanocapsules of Matricaria recutita L. extract formation by the emulsion-diffusion process

    Science.gov (United States)

    Esmaeili, Akbar; Saremnia, Betsabe; Koohian, Ata; Rezazadeh, Shamsali

    2011-10-01

    Nanocapsules coated by medicinal plants have many applications in drug manufacturing. Medicinal plants can be loaded on nanocapsules with polyesteric triblock copolymer poly ethylene glycol-poly butylene adipate-poly ethylene glycol (PEG-PBA-PEG) as shell and olive oil can be introduced as a core of nanocapsules by a method known as polymer deposition solvent evaporation method. In this research, first, certain amount of polymer, Matricaria recutita extract and olive oil were mixed with acetone and then, water was added to the solution using magnetic stirrer. After which the acetone was removed by vacuuming and finally nanocapsules were found by freezing-drier. The study showed the size of nanocapsules depends on variety of factors such as the ratio of polymer to oil and concentration of polymers and plant extract. The nanocapsules were identified by scanning electron microscopy (SEM) and zeta potential sizer (ZPS), Fourier-transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR).

  20. Application of radiation technology to develop green tea leaf as a natural resource for the cosmetic industry

    Science.gov (United States)

    Byun, Myung Woo; Jo, Cheorun; Lee, Ju Woon; Jo, Sung Kee; Kim, Kwan Soo

    2004-09-01

    The irradiation of natural resources such as green tea leaf, persimmon leaf, licorice root and stolon or Lonicera japonica improved the color of the extract, resulting in a higher applicability without any adverse change to the beneficial functions such as the inhibitory effects of oxidation, melanin hyperpigmentation on the skin, and others. To investigate the application of irradiated natural resources for a real cosmetic composition, the physiological activities of irradiated green tea leaf extract powder dissolved in butylene glycol and ethanol were compared to a commercial green tea extract product. Furthermore, a cream lotion was manufactured using the powder and the physiological activities were compared. Results showed that the irradiation of the green tea leaf extract and the freeze-dried powder from the extract had the same physiological activities as the commercial product in a cosmetic composition.

  1. Property profile of nanostructured blends of amine functionalized elastomer and epoxy

    Energy Technology Data Exchange (ETDEWEB)

    Zulfiqar, Sonia; Sarwar, Muhammad Ilyas [National University of Sciences and Technology (NUST), Islamabad (Pakistan); Fatima, Irum [Quaid-i-Azam University, Islamabad (Pakistan)

    2015-01-15

    Pure polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene (SEBS) was functionalized with amine moiety first through nitration, followed by reduction. The resulting amine modified SEBS was blended with various amounts of epoxy via in situ reactive approach. Thin blend films were initially cured at 120 .deg. C for 30 min and post cured at 180 .deg. C for 2 h. These films were then analyzed for their mechanical, thermal and morphological profile. Optimum improvement in tensile strength, modulus and toughness was observed with different epoxy loading in the blends. These blends were found thermally stable up to 300 .deg. C. The morphological studies indicated ample compatibility between the two components of blends.

  2. A "catalyst switch" Strategy for the sequential metal-free polymerization of epoxides and cyclic Esters/Carbonate

    KAUST Repository

    Zhao, Junpeng

    2014-06-24

    A "catalyst switch" strategy was used to synthesize well-defined polyether-polyester/polycarbonate block copolymers. Epoxides (ethylene oxide and/or 1,2-butylene oxide) were first polymerized from a monoalcohol in the presence of a strong phosphazene base promoter (t-BuP4). Then an excess of diphenyl phosphate (DPP) was introduced, followed by the addition and polymerization of a cyclic ester (ε-caprolactone or δ-valerolactone) or a cyclic carbonate (trimethylene carbonate), where DPP acted as both the neutralizer of phosphazenium alkoxide (polyether chain end) and the activator of cyclic ester/carbonate. This work has provided a one-pot sequential polymerization method for the metal-free synthesis of block copolymers from monomers which are suited for different types of organic catalysts. © 2014 American Chemical Society.

  3. One-pot synthesis of linear- and three-arm star-tetrablock quarterpolymers via sequential metal-free ring-opening polymerization using a "catalyst switch" strategy

    KAUST Repository

    Zhao, Junpeng

    2014-08-06

    A "catalyst switch" strategy has been used to sequentially polymerize four different heterocyclic monomers. In the first step, epoxides (1,2-butylene oxide and ethylene oxide) were successively polymerized from a monohydroxy or trihydroxy initiator in the presence of a strong phosphazene base promoter (t-BuP4). Then, an excess of diphenyl phosphate (DPP) was introduced, followed by addition and polymerization of a cyclic carbonate (trimethylene carbonate) and a cyclic ester (δ-valerolactone or ε-caprolactone). DPP acted as both neutralizer of the phosphazenium alkoxide (polyether chain end) and activator of the cyclic carbonate/ester. Using this method, linear- and star-tetrablock quarterpolymers were prepared in one pot. This work is emphasizing the strength of the previously developed catalyst switch strategy for the facile metal-free synthesis of complex macromolecular architectures. © 2014 Wiley Periodicals, Inc.

  4. The influence of polychromic light on the surface of MDI based polyurethane elastomer

    Energy Technology Data Exchange (ETDEWEB)

    Rosu, Dan, E-mail: drosu@icmpp.ro [' Petru Poni' Institute of Macromolecular Chemistry, 41A Gr. Ghica-Voda Alley, Iasi, 700487 Romania (Romania); Ciobanu, Constantin; Rosu, Liliana; Teaca, Carmen-Alice [' Petru Poni' Institute of Macromolecular Chemistry, 41A Gr. Ghica-Voda Alley, Iasi, 700487 Romania (Romania)

    2009-09-15

    A polyurethane elastomer was synthesized starting from 4,4' diphenylmethane diisocyanate and poly(ethyleneadipate)diol. Butylene glycol was used as chain extender. Surface properties after photo-degradation of the elastomer under the action of the radiation with {lambda} > 300 nm was monitored by FT-IR spectroscopy and contact angle measurements. The quality of polymer surface was observed under optical microscope. The formation of photo-Fries rearrangement and Norrish II reaction products during irradiation was associated with the gloss loss (from 100% for non-irradiated sample to 27% after 200 h irradiation time) and modification of wettability. There were also found significant modifications with irradiation time of both the glass transition temperature (T{sub g} decreases from 64 deg. C for non-irradiated sample to 53 deg. C after 200 h irradiation) and the swelling coefficient (an increase from 1.2% up to 2.5% is observed after 200 h irradiation).

  5. Antimicrobial Behavior of Semifluorinated-Quaternized Triblock Copolymers against Airborne and Marine Microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Park, D.; Finlay, J; Ward, R; Weinman, C; Krishnan, S; Park, M; Sohn, K; Callow, M; Callow, J; et. al.

    2010-01-01

    Semifluorinated-quaternized triblock copolymers (SQTCs) were synthesized by chemical modification of polystyrene-block-poly(ethylene-ran-butylene)-block-polyisoprene ABC triblock copolymers. Surface characterization of the polymers was performed by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) analysis. The surface of the SQTC showed very high antibacterial activity against the airborne bacterium Staphylococcus aureus with >99 % inhibition of growth. In contrast in marine fouling assays, zoospores of the green alga Ulva settled on the SQTC, which can be attributed to the positively charged surface. The adhesion strength of sporelings (young plants) of Ulva and Navicula diatoms (a unicellular alga) was high. The SQTC did not show marked algicidal activity.

  6. Comparison of precursor infiltration into polymer thin films via atomic layer deposition and sequential vapor infiltration using in-situ quartz crystal microgravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Padbury, Richard P.; Jur, Jesse S., E-mail: jsjur@ncsu.edu [Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-07-01

    Previous research exploring inorganic materials nucleation behavior on polymers via atomic layer deposition indicates the formation of hybrid organic–inorganic materials that form within the subsurface of the polymer. This has inspired adaptations to the process, such as sequential vapor infiltration, which enhances the diffusion of organometallic precursors into the subsurface of the polymer to promote the formation of a hybrid organic–inorganic coating. This work highlights the fundamental difference in mass uptake behavior between atomic layer deposition and sequential vapor infiltration using in-situ methods. In particular, in-situ quartz crystal microgravimetry is used to compare the mass uptake behavior of trimethyl aluminum in poly(butylene terephthalate) and polyamide-6 polymer thin films. The importance of trimethyl aluminum diffusion into the polymer subsurface and the subsequent chemical reactions with polymer functional groups are discussed.

  7. Hybrid ion-exchange membranes for fuel cells and separation processes

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Carretero, F.J.; Compan, V. [Departamento de Termodinamica Aplicada, ETSII, Universidad Politecnica de Valencia, 46020 Valencia (Spain); Riande, E. [Instituto de Ciencia y Tecnologia de Polimeros (CSIC), 28006 Madrid (Spain)

    2007-11-08

    This work reports the preparation and characterization of hybrid membranes cast from dispersions of inorganic fillers in sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene solutions. Silica gel, SBA-15 and sepiolite, all of them functionalized with phenylsulfonic acid groups, were used as fillers. For comparative purposes, the performance of composite membranes cast from dispersions of functionalized inorganic fillers in Nafion {sup registered} solutions was investigated. Inspection of the texture of the membranes by using SEM techniques shows that the fillers are better dispersed in sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene than in Nafion {sup registered}. The value of the water uptake for the membranes prepared from the former polyelectrolyte is in most cases at least three times that measured for hybrid Nafion {sup registered} membranes. The conductivity of the membranes was measured at 80 C by impedance spectroscopy obtaining values of 3.44, 6.90 and 3.54 S m{sup -1} for the hybrid membranes based on the triblock copolymer containing functionalized silica gel, SBA-15 and sepiolite fillers, respectively. These results compare very favourably with those obtained at 80 C for Nafion {sup registered} hybrid membranes containing silica gel, SBA-15 and sepiolite, all of them fuctionalized with phenylsulfonic acid groups, whose conductivities are, 2.84, 6.75 and 3.31 S m{sup -1}, respectively. Resistance measurements carried out under controlled humidity conditions show that the conductivity of sulfonated triblock copolymer membranes containing functionalized SBA-15 filler undergoes a rather sharp increase when they are conditioned under an atmosphere of 75%, or larger, relative humidity. (author)

  8. Isolation and characterization of Arctic microorganisms decomposing bioplastics.

    Science.gov (United States)

    Urbanek, Aneta K; Rymowicz, Waldemar; Strzelecki, Mateusz C; Kociuba, Waldemar; Franczak, Łukasz; Mirończuk, Aleksandra M

    2017-12-01

    The increasing amount of plastic waste causes significant environmental pollution. In this study, screening of Arctic microorganisms which are able to degrade bioplastics was performed. In total, 313 microorganisms were isolated from 52 soil samples from the Arctic region (Spitsbergen). Among the isolated microorganisms, 121 (38.66%) showed biodegradation activity. The ability of clear zone formation on emulsified poly(butylene succinate-co-adipate) (PBSA) was observed for 116 microorganisms (95.87%), on poly(butylene succinate) (PBS) for 73 microorganisms (60.33%), and on poly(ɛ-caprolactone) (PCL) for 102 microorganisms (84.3%). Moreover, the growth of microorganisms on poly(lactic acid) (PLA) agar plates was observed for 56 microorganisms (46.28%). Based on the 16S rRNA sequence, 10 bacterial strains which showed the highest ability for biodegradation were identified as species belonging to Pseudomonas sp. and Rhodococcus sp. The isolated fungal strains were tested for polycaprolactone films and commercial corn and potato starch bags degradation under laboratory conditions. Strains 16G (based on the analysis of a partial 18S rRNA sequence, identified as Clonostachys rosea) and 16H (identified as Trichoderma sp.) showed the highest capability for biodegradation. A particularly high capability for biodegradation was observed for the strain Clonostachys rosea, which showed 100% degradation of starch films and 52.91% degradation of PCL films in a 30-day shake flask experiment. The main advantage of the microorganisms isolated from Arctic environment is the ability to grow at low temperature and efficient biodegradation under this condition. The data suggest that C. rosea can be used in natural and laboratory conditions for degradations of bioplastics.

  9. Enhancing the Mechanical Properties of Biodegradable Polymer Blends Using Tubular Nanoparticle Stitching of the Interfaces.

    Science.gov (United States)

    Guo, Yichen; He, Shan; Yang, Kai; Xue, Yuan; Zuo, Xianghao; Yu, Yingjie; Liu, Ying; Chang, Chung-Chueh; Rafailovich, Miriam H

    2016-07-13

    "Green" polymer nanocomposites were made by melt blending biodegradable poly(lactic acid) (PLA) and poly(butylene adipate-co-butylene terephthalate) (PBAT) with either montmorillonite clays (Cloisite Na(+)), halloysite nanotubes (HNTs), the resorcinol diphenyl phosphate (RDP)-coated Cloisite Na(+), and coated HNTs. A technique for measuring the work of adhesion (Wa) between nanoparticles and their matrixes was used to determine the dispersion preference of the nanoparticles in the PLA/PBAT blend system. Transmission electron microscopy (TEM) images of thin sections indicated that even though both RDP-coated nanotubes and clay platelets segregated to the interfacial regions between the two immiscible polymers, only the platelets, having the larger specific surface area, were able to reduce the PBAT domain sizes. The ability of clay platelets to partially compatibilize the blend was further confirmed by the dynamic mechanical analysis (DMA) which showed that the glass transition temperatures of two polymers tended to shift closer. No shift was observed with either coated or uncoated HNTs samples. Izod impact testing demonstrated that the rubbery PBAT phase greatly increased the impact strength of the unfilled blend, but addition of only 5% of treated clay decreased the impact strength by nearly 50%. On the other hand, an increase of 9% relative to the unfilled blend sample was observed with the addition of 5% treated nanotubes. TEM cross-section analysis confirmed that the RDP-coated clay platelets covered most of the interfacial area. On one hand, this enabled them to reduce the interfacial tension effectively; on the other hand, it prevented chain entanglements across the phase boundary and increased the overall brittleness, which was confirmed by rheology measurements. In contrast, the RDP-coated HNTs were observed to lie perpendicular to the interface, which made them less effective in reducing interfacial tension but encouraged interfacial entanglements across

  10. Amphiphilic Surface Active Triblock Copolymers with Mixed Hydrophobic and Hydrophilic Side Chains for Tuned Marine Fouling-Release Properties

    Energy Technology Data Exchange (ETDEWEB)

    Park, D.; Weinman, C; Finlay, J; Fletcher, B; Paik, M; Sundaram, H; Dimitriou, M; Sohn, K; Callow, M; et al.

    2010-01-01

    Two series of amphiphilic triblock surface active block copolymers (SABCs) were prepared through chemical modification of two polystyrene-block-poly(ethylene-ran-butylene)-block-polyisoprene ABC triblock copolymer precursors. The methyl ether of poly(ethylene glycol) [M{sub n} {approx} 550 g/mol (PEG550)] and a semifluorinated alcohol (CF{sub 3}(CF{sub 2}){sub 9}(CH{sub 2}){sub 10}OH) [F10H10] were attached at different molar ratios to impart both hydrophobic and hydrophilic groups to the isoprene segment. Coatings on glass slides consisting of a thin layer of the amphiphilic SABC deposited on a thicker layer of an ABA polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene thermoplastic elastomer were prepared for biofouling assays with algae. Dynamic water contact angle analysis, X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) measurements were utilized to characterize the surfaces. Clear differences in surface structure were realized as the composition of attached side chains was varied. In biofouling assays, the settlement (attachment) of zoospores of the green alga Ulva was higher for surfaces incorporating a large proportion of the hydrophobic F10H10 side chains, while surfaces with a large proportion of the PEG550 side chains inhibited settlement. The trend in attachment strength of sporelings (young plants) of Ulva did not show such an obvious pattern. However, amphiphilic SABCs incorporating a mixture of PEG550 and F10H10 side chains performed the best. The number of cells of the diatom Navicula attached after exposure to flow decreased as the content of PEG550 to F10H10 side chains increased.

  11. Structure and Barrier Properties of Multinanolayered Biodegradable PLA/PBSA Films: Confinement Effect via Forced Assembly Coextrusion.

    Science.gov (United States)

    Messin, Tiphaine; Follain, Nadège; Guinault, Alain; Sollogoub, Cyrille; Gaucher, Valérie; Delpouve, Nicolas; Marais, Stéphane

    2017-08-30

    Multilayer coextrusion processing was applied to produce 2049-layer film of poly(butylene succinate-co-butylene adipate) (PBSA) confined against poly(lactic acid) (PLA) using forced assembly, where the PBSA layer thickness was about 60 nm. This unique technology allowed to process semicrystalline PBSA as confined polymer and amorphous PLA as confining polymer in a continuous manner. The continuity of PBSA layers within the 80/20 wt % PLA/PBSA layered films was clearly evidenced by atomic force microscopy (AFM). Similar thermal events to the reference films were revealed by thermal studies; indicating no diffusion of polymers during the melt-processing. Mechanical properties were measured for the multilayer film and the obtained results were those expected considering the fraction of each polymer, revealing the absence of delamination in the PLA/PBSA multinanolayer film. The confinement effect induced by PLA led to a slight orientation of the crystals, an increase of the rigid amorphous fraction (RAF) in PBSA with a densification of this fraction without changing film crystallinity. These structural changes allowed to strongly improve the water vapor and gas barrier properties of the PBSA layer into the multilayer film up to two decades in the case of CO2 gas. By confining the PBSA structure in very thin and continuous layers, it was then possible to improve the barrier performances of a biodegradable system and the resulting barrier properties were successfully correlated to the effect of confinement on the microstructure and the chain segment mobility of the amorphous phase. Such investigation on these multinanolayers of PLA/PBSA with the aim of evidencing relationships between microstructure implying RAF and barrier performances has never been performed yet. Besides, gas and water permeation results have shown that the barrier improvement obtained from the multilayer was mainly due to the reduction of solubility linked to the reduction of the free volume while

  12. Estudio del comportamiento mecánico de gelés físicos termorreversibles obtenidos a partir de copolímeros tribloques de PS-b-poli(etileno/butileno-PS en un disolvente selectivo del bloque central

    Directory of Open Access Journals (Sweden)

    Hernáez, E.

    2001-04-01

    Full Text Available The thermoreversible gelation of three triblock copolymers polystyrene-bpoly( ethylene/butylene-b-polystyrene, with different molar mass and a similar chemical composition, in n-octane was studied. The solvent is selective for the middle poly(ethylene/butylene block of the copolymers. The influence of the molar mass of the three copolymers on the gelation and on the mechanical properties of the gels was analysed. The sol-gel transition temperatures, Tgel, have been determined and they increase with the copolymer concentration and the copolymer molar mass. On the other hand, the mechanical properties of the different gels were examined through oscillatory shear and compressive stress relaxation measurements. The concentration dependence of the elastic storage modulus, G’, for the three copolymer studied fit a sole straight line in a doublelogarithmic scale and its slope (2.22 is close to that expected for systems in good solvents (2.25. As the temperature is near to the sol-gel transition temperature, the elastic modulus are smaller and the relaxation rates are higher.

    Se ha estudiado la influencia del peso molecular del copolímero en la formación de geles físicos termoreversibles de copolímeros tribloque de la forma poliestireno-b-poli(etileno/butileno-b-poliestireno (SEBS en n-octano y en sus propiedades mecánicas. Se ha determinado la temperatura de formación de los geles, Tgel, concluyendo que éstas aumentan con la concentración y el peso molecular del copolímero. Por otra parte, se han medido las propiedades mecánicas de los geles empleando ensayos de torsión y relajación de tensión, en función de la concentración de copolímero. La dependencia doble logarítmica del módulo G' con la concentración de copolímero para los tres SEBS se ajusta a una línea recta de pendiente 2,22, próxima a la predicha para geles preparados químicamente (2,25. Cuanto más próxima está la temperatura de medida

  13. Interaction of surfactants with block-copolymer systems in the presence of Hofmeister anions

    Science.gov (United States)

    Jadoon, Quratulain; Bibi, Iram; Mehmood, Khalid; Sajjad, Saman; Nawaz, Mohsan; Ali, Farman; Bibi, Saira; ur-Rehman, Wajid; Bano, Shakeela; Usman, Mohammad

    2017-03-01

    The interactions of block copolymers poly (ethylene oxide butylene oxide), E58B7 and E58B11 with anionic surfactant sodium dodecyl sulfate and cationic surfactant cetyltrimethylammonium bromide were studied by using different techniques such as surface tension, conductivity, and dynamic light scattering. The effect of salts in the Hofmeister series on polymer-surfactant systems was also investigated. The interactions were found to be dependent on both surfactant and polymer concentrations. The results were utilized to compute different thermodynamic parameters including enthalpy of micellization (ΔH m), entropy of micellization (ΔS m), free energy of adsorption (ΔG ads) and free energy of micellization (ΔG mic). For diblock-copolymer surfactant systems the negative value of (ΔG mic) shows that the process of micelle formation is thermodynamically favorable. The solubilization in surfactant micelles altered the physicochemical properties of the block copolymer. The value of critical aggregation concentration decreases with the addition of Hofmeister anions, and the decrease is more pronounced for sodium fluoride as compared to sodium iodide.

  14. Novel flexible nerve conduits made of water-based biodegradable polyurethane for peripheral nerve regeneration.

    Science.gov (United States)

    Hsu, Shan-Hui; Chang, Wen-Chi; Yen, Chen-Tung

    2017-05-01

    Peripheral nerve conduits were fabricated from biodegradable polyurethane (PU) which was synthesized by a waterborne process. The biodegradable PU was based on poly(ε-caprolactone) diol and polyethylene butylene adipate diol (2:3 molar ratio) as the soft segment. Conduits formed by the freeze-drying process had asymmetric microporous structure. The PU nerve conduits were used to bridge a 10-mm gap in rat sciatic nerve. Nerve regeneration was evaluated by walking track analysis, magnetic resonance imaging (MRI), electrophysiological, and histological analyses. Results demonstrated that after 6 weeks, walking function was recovered by 40%. MR images showed that the transected nerve was reconnected after 3 weeks and the diameter of the regenerated nerve increased from 3 to 6 weeks. The nerve conduction velocity of the regenerated nerve reached 50% of the normal value after 6 weeks. Histological examination revealed that the cross-sectional area of the regenerated nerve at the midconduit was 0.24 mm2 after 6 weeks. The efficacy of PU nerve conduits based on functional recovery and histology was superior to that of commercial conduits (Neurotube). The PU nerve conduit developed in this study may be a potential candidate for clinical peripheral nerve tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1383-1392, 2017. © 2017 Wiley Periodicals, Inc.

  15. The micro thermal analysis of polymers

    CERN Document Server

    Grandy, D B

    2002-01-01

    This study is concerned with the development of micro-thermal analysis as a technique for characterising heterogeneous polymers. It is divided into two main parts. In the first part, the use of miniature Wollaston wire near-field thermal probes mounted in an atomic force microscope (AFM) to carry out highly localised thermal analysis (L-TA) of amorphous and semi-crystalline polymers is investigated. Here, the temperature of the probe sensor or tip is scanned over a pre-selected temperature range while in contact with the surface of a sample. It is thereby used to heat a volume of material of the order of several cubic micrometres. The effect of the glass transition, cold crystallisation, melting and degree of crystallinity on L-TA measurements is investigated. The materials used are poly(ethylene terephthalate), polystyrene and fluorocarbon-coated poly(butylene terephthalate). The primary measurements are the micro- or localised analogues of thermomechanical analysis (L-TMA) and differential thermal analysis ...

  16. Investigation of Thermal and Thermomechanical Properties of Biodegradable PLA/PBSA Composites Processed via Supercritical Fluid-Assisted Foam Injection Molding

    Directory of Open Access Journals (Sweden)

    Sai Aditya Pradeep

    2017-01-01

    Full Text Available Bio-based polymer foams have been gaining immense attention in recent years due to their positive contribution towards reducing the global carbon footprint, lightweighting, and enhancing sustainability. Currently, polylactic acid (PLA remains the most abundant commercially consumed biopolymer, but suffers from major drawbacks such as slow crystallization rate and poor melt processability. However, blending of PLA with a secondary polymer would enhance the crystallization rate and the thermal properties based on their compatibility. This study investigates the physical and compatibilized blends of PLA/poly (butylene succinate-co-adipate (PBSA processed via supercritical fluid-assisted (ScF injection molding technology using nitrogen (N2 as a facile physical blowing agent. Furthermore, this study aims at understanding the effect of blending and ScF foaming of PLA/PBSA on crystallinity, melting, and viscoelastic behavior. Results show that compatibilization, upon addition of triphenyl phosphite (TPP, led to an increase in molecular weight and a shift in melting temperature. Additionally, the glass transition temperature (Tg obtained from the tanδ curve was observed to be in agreement with the Tg value predicted by the Gordon–Taylor equation, further confirming the compatibility of PLA and PBSA. The compatibilization of ScF-foamed PLA–PBSA was found to have an increased crystallinity and storage modulus compared to their physically foamed counterparts.

  17. Preparation and application of conducting polymer/Ag/clay composite nanoparticles formed by in situ UV-induced dispersion polymerization.

    Science.gov (United States)

    Zang, Limin; Qiu, Jianhui; Yang, Chao; Sakai, Eiichi

    2016-02-03

    In this work, composite nanoparticles containing polypyrrole, silver and attapulgite (PPy/Ag/ATP) were prepared via UV-induced dispersion polymerization of pyrrole using ATP clay as a templet and silver nitrate as photoinitiator. The effects of ATP concentration on morphology, structure and electrical conductivity were studied. The obtained composite nanoparticles with an interesting beads-on-a-string morphology can be obtained in a short time (10 min), which indicates the preparation method is facile and feasible. To explore the potential applications of the prepared PPy/Ag/ATP composite nanoparticles, they were served as multifunctional filler and blended with poly(butylene succinate) (PBS) matrix to prepare biodegradable composite material. The distribution of fillers in polymer matrix and the interfacial interaction between fillers and PBS were confirmed by scanning electron microscope, elemental mapping and dynamic mechanical analysis. The well dispersed fillers in PBS matrix impart outstanding antibacterial property to the biodegradable composite material as well as enhanced storage modulus due to Ag nanoparticles and ATP clay. The biodegradable composite material also possesses modest surface resistivity (10(6)~ 10(9) Ω/◻).

  18. [The determination of glucose, sucrose and fructose by the method of capillary electrophoresis].

    Science.gov (United States)

    Yakuba, Yu F; Markovsky, M G

    2015-01-01

    The possibilities of different regimes of micellar capillary electrophoresis using negative polarity and alkaline electrolyte for determination of glucose, sucrose, fructose in extracts of vegetative organs of plants and products of fruits and grapes processing have been studied. A comparative evaluation of the limits of detection of glucose, sucrose, fructose for developed electrolytes have been performed, the advantages and disadvantages of techniques have been discussed. It is recommended to use an aqueous electrolyte containing 0.5% potassium sorbate, 0.62% cetyltrimethylammonium bromide, and 0.02% potassium hydroxide. The analyzed components were detected at 254 nm. The sample was dosed hydrodynamically (30 mbar, 5 sec). Negative voltage 16 kV is recommended, current--54 ± 4 µA, capillary thermostating at 24 °C is applied, the analysis time--15 min. The detection limits for fructose and glucose is 0.03 g/dm3 to 0.07 g of sucrose/dm3. Linearity is stored for each component to 5.0 g/dm 3 inclusive. Electrophoretic mobility of carbohydrates was (10(-4) sm2V(-1)sec(-1)): fructose--3.12, glucose--3.03, sucrose--2.74. Approximate time of release: glucose--13 min, sucrose--13.5 min, fructose--12.5 min. The developed options for mass concentration determining of mono- and disaccharides provide complete separation of the components. Anions, glycerol, ethylene glycol, propylene glycol and butylene isomers do not affect the analysis results.

  19. Controlled lecithin release from a hierarchical architecture on blood-contacting surface to reduce hemolysis of stored red blood cells.

    Science.gov (United States)

    Shi, Qiang; Fan, Qunfu; Ye, Wei; Hou, Jianwen; Wong, Shing-Chung; Xu, Xiaodong; Yin, Jinghua

    2014-06-25

    Hemolysis of red blood cells (RBCs) caused by implant devices in vivo and nonpolyvinyl chloride containers for RBC preservation in vitro has recently gained much attention. To develop blood-contacting biomaterials with long-term antihemolysis capability, we present a facile method to construct a hydrophilic, 3D hierarchical architecture on the surface of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS) with poly(ethylene oxide) (PEO)/lecithin nano/microfibers. The strategy is based on electrospinning of PEO/lecithin fibers onto the surface of poly [poly(ethylene glycol) methyl ether methacrylate] [P(PEGMEMA)]-modified SEBS, which renders SEBS suitable for RBC storage in vitro. We demonstrate that the constructed 3D architecture is composed of hydrophilic micro- and nanofibers, which transforms to hydrogel networks immediately in blood; the controlled release of lecithin is achieved by gradual dissolution of PEO/lecithin hydrogels, and the interaction of lecithin with RBCs maintains the membrane flexibility and normal RBC shape. Thus, the blood-contacting surface reduces both mechanical and oxidative damage to RBC membranes, resulting in low hemolysis of preserved RBCs. This work not only paves new way to fabricate high hemocompatible biomaterials for RBC storage in vitro, but provides basic principles to design and develop antihemolysis biomaterials for implantation in vivo.

  20. Fluorinated Amphiphilic Polymers and Their Blends for Fouling-Release Applications: The Benefits of a Triblock Copolymer Surface

    KAUST Repository

    Sundaram, Harihara S.

    2011-09-28

    Surface active triblock copolymers (SABC) with mixed polyethylene glycol (PEG) and two different semifluorinated alcohol side chains, one longer than the other, were blended with a soft thermoplastic elastomer (TPE), polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS). The surface composition of these blends was probed by X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The surface reconstruction of the coatings in water was monitored qualitatively by dynamic water contact angles in air as well as air bubble contact angle measurements in water. By blending the SABC with SEBS, we minimize the amount of the SABC used while achieving a surface that is not greatly different in composition from the pure SABC. The 15 wt % blends of the SABC with long fluoroalkyl side chains showed a composition close to that of the pure SABC while the SABC with shorter perfluoroakyl side chains did not. These differences in surface composition were reflected in the fouling-release performance of the blends for the algae, Ulva and Navicula. © 2011 American Chemical Society.

  1. Binary release of ascorbic acid and lecithin from core-shell nanofibers on blood-contacting surface for reducing long-term hemolysis of erythrocyte.

    Science.gov (United States)

    Shi, Qiang; Fan, Qunfu; Ye, Wei; Hou, Jianwen; Wong, Shing-Chung; Xu, Xiaodong; Yin, Jinghua

    2015-01-01

    There is an urgent need to develop blood-contacting biomaterials with long-term anti-hemolytic capability. To obtain such biomaterials, we coaxially electrospin [ascorbic acid (AA) and lecithin]/poly (ethylene oxide) (PEO) core-shell nanofibers onto the surface of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS) that has been grafted with poly (ethylene glycol) (PEG) chains. Our strategy is based on that the grafted layers of PEG render the surface hydrophilic to reduce the mechanical injure to red blood cells (RBCs) while the AA and lecithin released from nanofibers on blood-contacting surface can actively interact with RBCs to decrease the oxidative damage to RBCs. We demonstrate that (AA and lecithin)/PEO core-shell structured nanofibers have been fabricated on the PEG grafted surface. The binary release of AA and lecithin in the distilled water is in a controlled manner and lasts for almost 5 days; during RBCs preservation, AA acts as an antioxidant and lecithin as a lipid supplier to the membrane of erythrocytes, resulting in low mechanical fragility and hemolysis of RBCs, as well as high deformability of stored RBCs. Our work thus makes a new approach to fabricate blood-contacting biomaterials with the capability of long-term anti-hemolysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Mejora de la inercia térmica de mezclas de sebs mediante la adición de materiales con cambio de fase (PCMS a 28º

    Directory of Open Access Journals (Sweden)

    David Juárez Varón

    2012-05-01

    Full Text Available In this work, microencapsulated phase change materials (PCMs with a melting temperature of 28 ºC have been used to improve thermal inertia phenomena on an elastomeric matrix of styrene-ethylene/butylenes-styrene (SEBS material. The amount of PCMs has varied in the 1-10 wt. % and these materials have been processed by conventional injection molding without PCM degradation. Mechanical characterization of SEBS-PCM compounds has been carried out and the obtained results show good maintenance of both resistant and ductile properties for PCM amounts comprised in the 1-5 wt. % range. SEM analysis has revealed good interaction between PCM microcapsules and SEBS matrix which is a critical aspect to obtain good mechanical performance. The effect of PCM addition on thermal inertia has been evaluated by active infrared thermography, showing a remarkable effect on thermal regulation of SEBS in the temperature range close to the melting point of the PCM (28 ºC. This thermoregulation effect is more accurate as the PCM content increases. Also, cooling curves have been constructed in order to quantify the thermal inertia effect in a cooling process.

  3. Oil-based gel phantom for ultrasound and optical imaging

    Science.gov (United States)

    Cabrelli, Luciana C.; Pelissari, Pedro I. B. G. B.; Aggarwal, Lucimara P.; Deana, Alessandro M.; Carneiro, Antonio A. O.; Pavan, Theo. Z.

    2015-06-01

    Water-based materials are commonly used in phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. Styrene-Ethylene/Butylene-Styrene (SEBS) copolymer in mineral oil samples were made varying the SEBS concentration between 5-15%, and low-density polyethylene (LDPE) between 0-9%. Acoustic properties such as speed of sound and attenuation coefficient were obtained by the substitution technique with frequencies ranging from 2.25-10 MHz, and were consistent to that of soft tissue. These properties were controlled varying SEBS and LDPE concentration; speed of sound from 1445-1480 m/s, and attenuation from 0.86-11.31 dB/cm were observed. SEBS gels with 0% of LDPE were optically transparent, presenting low optical absorption and scattering coefficients in the visible region of the spectrum. In order to fully characterize the optical properties of the samples, the reflectances of the surfaces were measured, along with the absorption. Scattering and absorption coefficients ranging from 400 nm to 1200 nm were calculated for each compound. The results showed that the presence of LDPE increased absorption and scattering of the phantoms. The results suggest the copolymer gels are promising for ultrasound and optical imaging, what make them also potentially useful for photoacoustic imaging.

  4. Time-composition superpositioning in the rheological behavior of triblock copolymer/selective co-solvent blends

    Science.gov (United States)

    Krishnan, Arjun; Bukovnik, Rudolf; Spontak, Richard

    2009-03-01

    Thermoplastic elastomers composed of styrenic triblock copolymers are of great importance in applications such as adhesives and vibration dampening due to their resilience and facile processing. The swelling of these polymers by adding midblock selective solvents or oligomers provides an easy route by which to modify the morphology and mechanical behavior of these systems. In this study we consider a ternary blend of a poly[styrene-b-(ethylene-co-butylene)-b-styrene] triblock copolymer and mixtures of two midblock selective co-solvents: a mineral oil that is liquid at ambient temperature, and a glassy tackifier resin that exhibits limited solubility in the midblock matrix. We use dynamic rheology to study the viscoelastic response of a wide variety of systems under oscillatory shear. The copolymer concentration is varied between 15 to 35 wt%, while the resin/oil ratio in the midblock-solvent matrix is independently varied. Frequency spectra acquired at ambient temperature display viscoelastic behavior that shifts in the frequency domain depending on the resin/oil ratio. At high oil loadings, the materials behave as physical gels. For each copolymer concentration, all the frequency data can be shifted by time-composition superpositioning to yield a single master-curve.

  5. Morphology of biaxially stretched triblock copolymer gels using SAXS

    Science.gov (United States)

    Krishnan, Arjun; Ghosh, Tushar; Spontak, Richard

    2009-03-01

    Gels of styrenic triblock copolymers swollen by a low-volatility, midblock-selective oil behave as high-strain, low-field dielectric elastomers in the design of electroactive polymeric actuators. A standard configuration of such devices involves stretching, or ``prestraining,'' the elastomer film biaxially. However, little is known about the effect of biaxial prestrain on copolymer morphology. In this study, small-angle X-ray scattering (SAXS) is used to probe the nanostructure of gels composed of poly[styrene-b-(ethylene-co-butylene)-b-styrene] and mineral oil by systematically changing the concentration of polymer from 5 to 30 wt% and the biaxial prestrain from 0 to 300%. In the azimuthally integrated intensity profiles, the form factor due to scattering from polystyrene microdomains correlates strongly with polymer concentration and does not change with the applied prestrain, indicating that the polystyrene crosslinks remain as polydisperse spheres. The structure factor data correlates with prestrain, and is fitted using the Percus-Yevick approximation for interacting spheres. While a hard sphere interaction model is sufficient for unstrained gels, we resort to a square shoulder hard sphere potential for strained samples.

  6. Development of an active biodegradable film containing tocopherol and avocado peel extract

    Directory of Open Access Journals (Sweden)

    J.C.F. Fidelis

    2015-12-01

    Full Text Available Thermoplastic starch (TPS films and poly(butylene adipate co-terephthalate (PBAT (60/40 m/m containing TOCO-70 (tocopherol/soybean oil 70/30 m/m and avocado peel extract (ExA were produced using blown film extrusion. The formulations of the 5 films (FC/F1/F2/F3 and F4 were established through mixture design with constraints maintaining constant PBAT and TPS proportion, and varying the antioxidant concentrations. Adding antioxidants reduced the water vapour permeability (Kw of the films, with formulation F2 presenting higher decrease in relationto FC, 77.8%. The presence of ExA improved the mechanical properties of the films. The production of the films was determined to be viable after they presented good processability in a pilotextruder, as well as mechanical properties appropriate to production and utilization in industry.The presence of ExA and TOCO 70 provided the films with antioxidant activity; their application as active packaging requires further studies.

  7. Novel Random PBS-Based Copolymers Containing Aliphatic Side Chains for Sustainable Flexible Food Packaging

    Directory of Open Access Journals (Sweden)

    Giulia Guidotti

    2017-12-01

    Full Text Available In the last decade, there has been an increased interest from the food packaging industry toward the development and application of biodegradable and biobased plastics, to contribute to the sustainable economy and to reduce the huge environmental problem afflicting the planet. In this framework, the present paper describes the synthesis of novel PBS (poly(butylene succinate-based random copolymers with different composition containing glycol sub-units characterized by alkyl pendant groups of different length. The prepared samples were subjected to molecular, thermal, diffractometric and mechanical characterization. The barrier performances to O2, CO2 and N2 gases were also evaluated, envisioning for these new materials an application in food packaging. The presence of the side alkyl groups did not alter the thermal stability, whereas it significantly reduced the sample crystallinity degree, making these materials more flexible. The barrier properties were found to be worse than PBS; however, some of them were comparable to, or even better than, those of Low Density Polyethylene (LDPE, widely employed for flexible food packaging. The entity of variations in the final properties due to copolymerization were more modest in the case of the co-unit with short side methyl groups, which, when included in the PBS crystal lattice, causes a more modest decrement of crystallinity degree.

  8. CO2-Philic polymer membrane with extremely high separation performance

    KAUST Repository

    Yave, Wilfredo

    2010-01-12

    Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)-poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high ( > 2 m3 m -2 h-1 bar-1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO 2 capture. © 2009 American Chemical Society.

  9. Changing Mechanical Strength in Cr(III)- Metallosupramolecular Polymers with Ligand Groups and Light Irradiation.

    Science.gov (United States)

    Razgoniaev, Anton O; Butaeva, Evgeniia V; Iretskii, Alexei V; Ostrowski, Alexis D

    2016-06-06

    We have demonstrated the ability to control the mechanical properties of metallosupramolecular materials via choice of ligand binding group, as well as with external light irradiation. These photoresponsive Cr(III)-based materials were prepared from a series of modified hydrogenated poly(ethylene-co-butylene) polymers linked through metal-ligand interactions between a Cr(III) metal center and pyridyl ligand termini of the polymers. The introduction of these Cr(III)-pyridine bonds gave rise to new mechanical and optical properties of the polymer materials. Depending on the type of pyridyl ligand, density functional theory calculations revealed changes in coordination to the Cr(III), which ultimately led to materials with significantly different mechanical properties. Electronic excitation of the Cr(III) materials with 450 and 655 nm CW lasers (800 mW/cm(2)) resulted in generation of excited state photophysical processes which led to temporary softening of the materials up to 143 kPa (41.5%) in storage modulus (G') magnitude. The initial mechanical strength of the materials was recovered when the light stimulus was removed, and no change in mechanical properties was observed with light irradiation where there was no absorbance by the Cr(III) moiety. These materials demonstrate that introduction of metal-ligand bonding interactions into polymers enables the design and synthesis of photoresponsive materials with tunable optical-mechanical properties not seen in traditional polymeric materials.

  10. [1,4-Bis(diphenylphosphanylbutane-κ2P,P′]dibromidopalladium(II

    Directory of Open Access Journals (Sweden)

    Kwang Ha

    2014-02-01

    Full Text Available In the title complex, [PdBr2(C28H28P2], the PdII ion has a distorted cis-Br2P2 square-planar coordination geometry defined by two P atoms from the chelating 1,4-bis(diphenylphosphanylbutane ligand and two Br− anions. The four phenyl rings are inclined to the least-squares plane of the PdBr2P2 unit [maximum deviation = 0.1294 (7 Å], making dihedral angles of 66.3 (2, 87.2 (2, 68.8 (2 and 86.8 (2°. The butylene chain is in a gauche conformation, with a C—C—C—C torsion angle of 57.0 (8°. Intermolecular C—H...Br hydrogen bonds link the complex molecules into supramolecular layers in the ab plane. Weak π–π interactions, both intra- and intermolecular [shortest inter-centroid distance = 4.598 (5 Å], are also noted in the three-dimensional architecture.

  11. The effect of multifunctional monomers/oligomers Additives on electron beam radiation crosslinking of poly (styrene-block-isoprene/butadiene-block-styrene) (SIBS)

    Science.gov (United States)

    Wu, Jinping; Soucek, Mark D.

    2016-02-01

    The effect of multifunctional monomers or oligomers (MFM/O) additives on electron beam (E-beam) radiation induced crosslinking of poly (styrene-block-isoprene/butadiene-block-styrene) (SIBS) was studied. Ten types of MFM/O were investigated, including trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane triacrylate (TMPTA), triallyl cyanurate (TAC), polybutadiene diacrylate (PB-diacrylate), ethylene glycol dimethylacrylate (EGDMA), butylene glycol dimethacrylate (BGDMA), 1,2-polybutadiene. The effects of MFM/O concentration and E-beam radiation dose on properties of SIBS were studied including tensile strength, elongation-at-break, modulus, gel content, equilibrium swelling and crosslink density. TMPTA significantly improved the tensile modulus and crosslink density of SIBS. SIBS with TMPTMA and TMTPMA with inhibitor showed a 50% increase in tensile strength. The solubility of MFM/O in SIBS was also investigated by a selective swelling method. The MFM/O were found to be soluble in both phases of SIBS. The viscosity of SIBS with methacrylate type MFM/O was stable at 200 °C.

  12. Modification of Biodegradable Polyesters Using Electron Beam

    Directory of Open Access Journals (Sweden)

    M. Suhartini

    2013-12-01

    Full Text Available Poly(4-Hydroxybutirat P4HB, Poly(butylene succinate-co-adipate PBSA and Poly(-caprolactone PCL were electron beam (EB-irradiated. Poly(4-Hydroxybutirat was irradiated without any polyfunctional monomers (PFM. While PBSA and PCL were irradiated in the presence of polyfunctional monomers such as Trimethallyl isocyanurate (TMAIC, Polyethyleneglycol dimethacrylate (2G, 4G, Trimethylolpropane trimethacrylate (TMPT and Tetramethylolmethane tetraacrylate (A-TMMT at ambient temperature. Aim of the study is to improve the properties of biodegradable polyester. It was pointed out that crosslinking yield of P4HB (6.39% gel was formed at dose of 90 kGy irradiated in vacuum conditions. Radiation degradation promoted, when P4HB was irradiated in air. The optimum crosslinking yield of PCL and PBSA respectively, were formed in the presence of 1% TMAIC at dose of 50 kGy. The biodegradability of the crosslinked PBSA evaluated by soil burial test is slightly retarded by increasing crosslinking yields.

  13. Impact of Alkyl Spacer Length on Aggregation Pathways in Kinetically Controlled Supramolecular Polymerization.

    Science.gov (United States)

    Ogi, Soichiro; Stepanenko, Vladimir; Thein, Johannes; Würthner, Frank

    2016-01-20

    We have investigated the kinetic and thermodynamic supramolecular polymerizations of a series of amide-functionalized perylene bisimide (PBI) organogelator molecules bearing alkyl spacers of varied lengths (ethylene to pentylene chains, PBI-1-C2 to PBI-1-C5) between the amide and PBI imide groups. These amide-functionalized PBIs form one-dimensional fibrous nanostructures as the thermodynamically favored states in solvents of low polarity. Our in-depth studies revealed, however, that the kinetic behavior of their supramolecular polymerization is dependent on the spacer length. Propylene- and pentylene-tethered PBIs follow a similar polymerization process as previously observed for the ethylene-tethered PBI. Thus, the monomers of these PBIs are kinetically trapped in conformationally restricted states through intramolecular hydrogen bonding between the amide and imide groups. In contrast, the intramolecularly hydrogen-bonded monomers of butylene-tethered PBI spontaneously self-assemble into nanoparticles, which constitute an off-pathway aggregate state with regard to the thermodynamically stable fibrous supramolecular polymers obtained. Thus, for this class of π-conjugated system, an unprecedented off-pathway aggregate with high kinetic stability could be realized for the first time by introducing an alkyl linker of optimum length (C4 chain) between the amide and imide groups. Our current system with an energy landscape of two competing nucleated aggregation pathways is applicable to the kinetic control over the supramolecular polymerization by the seeding approach.

  14. Nucleation Mechanisms of Aromatic Polyesters, PET, PBT, and PEN, on Single-Wall Carbon Nanotubes: Early Nucleation Stages

    Directory of Open Access Journals (Sweden)

    Adriana Espinoza-Martínez

    2012-01-01

    Full Text Available Nucleation mechanisms of poly(ethylene terephthalate (PET, poly(butylene terephthalate (PBT, and poly(ethylene naphthalate (PEN on single-wall carbon nanotubes (SWNTs are proposed, based on experimental evidence, theoretical epitaxy analysis, and semiempirical quantum chemical calculations. In order to elucidate early nucleation stages polyester-coated nanotubes were obtained from highly diluted solutions. High-resolution transmission electron microscopy (HRTEM revealed helical morphologies for PET/SWNTs and PEN/SWNTs and the formation of lobules with different orientations for PBT/SWNTs. To explain the morphological behavior one model was proposed based on crystallographic interactions, that is, epitaxy. Theoretical epitaxy calculations indicated that epitaxy is not possible from the strict epitaxy point of view. Instead, aromatic self-assembly mechanism was proposed based on π-π interactions and the chirality of the nanotube. It was proposed that the mechanism implies two steps to produce helical or lobular morphologies with different orientations. In the first step polymer chains were approached, aligned parallel to the nanotube axis and adsorbed due to electrostatic interactions and the flexibility of the molecule. However, due to π-π interactions between the aromatic rings of the polymer and the nanotube, in the second step chains reoriented on the nanotube surface depending on the chirality of the nanotube. The mechanism was supported by semi-empirical calculations.

  15. Colloidal Gold Nanoclusters Spiked Silica Fillers in Mixed Matrix Coatings: Simultaneous Detection and Inhibition of Healthcare-Associated Infections

    KAUST Repository

    Alsaiari, Shahad K.

    2017-01-25

    Healthcare-associated infections (HAIs) are the infections that patients get while receiving medical treatment in a medical facility with bacterial HAIs being the most common. Silver and gold nanoparticles (NPs) have been successfully employed as antibacterial motifs; however, NPs leaching in addition to poor dispersion and overall reproducibility are major hurdles to further product development. In this study, the authors design and fabricate a smart antibacterial mixed-matrix membrane coating comprising colloidal lysozyme-templated gold nanoclusters as nanofillers in poly(ethylene oxide)/poly(butylene terephthalate) amphiphilic polymer matrix. Mesoporous silica nanoparticles-lysozyme functionalized gold nanoclusters disperse homogenously within the polymer matrix with no phase separation and zero NPs leaching. This mixed-matrix coating can successfully sense and inhibit bacterial contamination via a controlled release mechanism that is only triggered by bacteria. The system is coated on a common radiographic dental imaging device (photostimulable phosphor plate) that is prone to oral bacteria contamination. Variation and eventually disappearance of the red fluorescence surface under UV light signals bacterial infection. Kanamycin, an antimicrobial agent, is controllably released to instantly inhibit bacterial growth. Interestingly, the quality of the images obtained with these coated surfaces is the same as uncoated surfaces and thus the safe application of such smart coatings can be expanded to include other medical devices without compromising their utility.

  16. Stereocomplex Formation in Incompatible Racemic Chiral Polylactide Block Copolymers

    Science.gov (United States)

    Sun, Lu; Zhu, Lei

    2006-03-01

    Stereocomplexes in incompatible racemic chiral polylactide (PLA) block copolymers have not been widely studied. In this work, we synthesized PLLA and PDLA containing block copolymers by ring opening polymerization of L- and D-lactides from hydroxyl-terminated hydrophilic [poly(ethylene oxide) (PEO)] and hydrophobic [poly(ethylene-co-1,2-butylene) (PEB)] oligomers, respectively. Two samples PEO-b-PLLA (2,000-5,400) and PEB-b-PDLA (4,200-5,400) were chosen. The stereocomplexes were cast from equal molar blends of above two block copolymers in chloroform solution, followed by two different thermal treatments before stereocomplex formation; The blend was either heated to 250 C and quickly quench to 160 C or heated to 250 C for 15 min and quench to 160 C for stereocomplex crystal growth. Before the formation of stereocomplexes, lamellar and cylindrical morphologies were observed in blends for the first and second thermal treatments, respectively, as evidenced by small-angle X-ray scattering (SAXS). After complete crystal growth, the 100% stereocomplexes was confirmed by differential scanning calorimetry and wide-angle X-ray diffraction (WAXD). The morphologies of stereocomplexes grown from these two pre-existing microphases (lamellar vs. cylindrical) were studied by time-resolved SAXS and transmission electron microscopy (TEM).

  17. Effect of O/W process parameters on Crataegus azarolus L nanocapsule properties.

    Science.gov (United States)

    Esmaeili, Akbar; Rahnamoun, Soraya; Sharifnia, Fariba

    2013-05-29

    Nanocapsules have many applications in the drug, cosmetic, fragrance, and food industries. In this study, Crataegus azarolus L. nanocapsules were prepared by a modified emulsion diffusion technique. In this technique a shell was first made from the polyester triblock copolymer poly(ethylene glycol)-poly(butylene adipate)-poly(ethylene glycol) (PEG-PBA-PEG) and then olive oil was set as the core of the nanocapsule by a method known as the polymer deposition solvent evaporation method. Varying amounts of C. azarolus extract, polymer, and olive oil were mixed in acetone and then added to water on a shaker. Finally, the acetone was removed by vacuuming. The size of the prepared nanocapsules were measured with a particle size analysis report (PSAR) and identified by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). Our experiments showed that the size of the nanocapsules depends on the preparation conditions, i.e., the ratio of polymer to oil and concentrations of polymer and plant extract. A ratio of 1:0.25 polymer to oil was shown to be more suitable for the formation of smaller nanocapsules of C. azarolus.

  18. Triblock Copolymers with Grafted Fluorine-Free Amphiphilic Non-Ionic Side Chains for Antifouling and Fouling-Release Applications

    Energy Technology Data Exchange (ETDEWEB)

    Y Cho; H Sundaram; C Weinman; M Paik; M Dimitriou; J Finlay; M Callow; J Callow; E Kramer; C Ober

    2011-12-31

    Fluorine-free, amphiphilic, nonionic surface active block copolymers (SABCs) were synthesized through chemical modification of a polystyrene-block-poly(ethylene-ran-butylene)-block-polyisoprene triblock copolymer precursor with selected amphiphilic nonionic Brij and other surfactants. Amphiphilicity was imparted by a hydrophobic aliphatic group combined with a hydrophilic poly(ethylene glycol) (PEG) group-containing moiety. The surfaces were characterized by dynamic water contact angle, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure (NEXAFS) analysis. In biofouling assays, settlement (attachment) of both spores of the green alga Ulva and cells of the diatom Navicula on SABCs modified with Brij nonionic side chains was significantly reduced relative to a PDMS standard, with a nonionic surfactant combining a PEG group and an aliphatic moiety demonstrating the best performance. Additionally, a fouling-release assay using sporelings (young plants) of Ulva and Navicula suggested that the SABC derived from nonionic Brij side chains also out-performed PDMS as a fouling-release material. Good antifouling and fouling-release properties were not demonstrated for the other two amphiphilic surfaces derived from silicone and aromatic group containing nonionic surfactants included in this study. The results suggest that small differences in chemical surface functionality impart more significant changes with respect to the antifouling settlement and fouling-release performance of materials than overall wettability behavior.

  19. Starch, cellulose acetate and polyester biodegradable sheets: Effect of composition and processing conditions.

    Science.gov (United States)

    Fialho E Moraes, Allan Robledo; Pola, Cícero Cardoso; Bilck, Ana Paula; Yamashita, Fabio; Tronto, Jairo; Medeiros, Eber Antonio Alves; Soares, Nilda de Fátima Ferreira

    2017-09-01

    The production of biodegradable plastic materials using natural resources has aroused increased attention due to environmental concerns. This study aimed to manufacture novel, commercially feasible, biodegradable sheets by flat die extrusion-calendering process produced with thermoplastic starch/plasticized cellulose acetate (TPS/PCA) and thermoplastic starch/plasticized cellulose acetate/poly (butylene adipate-co-terephthalate) (TPS/PCA/PBAT) blends, and to investigate the effects of composition and processing conditions, morphological characteristics, and thermal properties. The results showed that TPS/PCA and TPS/PCA/PBAT biodegradable sheets properties were highly dependent upon both composition and processing temperature. The morphological characteristics and thermal properties of the sheets demonstrated the good compatibility between TPS and PCA in TPS/PCA blends, mainly at higher processing temperatures, whereas TPS/PCA/PBAT sheets present a heterogeneous structure due to the poor compatibility between the components. TPS/PCA biodegradable sheets presented suitable processability and handleability characteristics that allow them to be considered as a novel eco-friendly, economically feasible alternative to conventional plastic materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Microwell scaffolds for the extrahepatic transplantation of islets of Langerhans.

    Directory of Open Access Journals (Sweden)

    Mijke Buitinga

    Full Text Available Allogeneic islet transplantation into the liver has the potential to restore normoglycemia in patients with type 1 diabetes. However, the suboptimal microenvironment for islets in the liver is likely to be involved in the progressive islet dysfunction that is often observed post-transplantation. This study validates a novel microwell scaffold platform to be used for the extrahepatic transplantation of islet of Langerhans. Scaffolds were fabricated from either a thin polymer film or an electrospun mesh of poly(ethylene oxide terephthalate-poly(butylene terephthalate (PEOT/PBT block copolymer (composition: 4000PEOT30PBT70 and were imprinted with microwells, ∼400 µm in diameter and ∼350 µm in depth. The water contact angle and water uptake were 39±2° and 52.1±4.0 wt%, respectively. The glucose flux through electrospun scaffolds was three times higher than for thin film scaffolds, indicating enhanced nutrient diffusion. Human islets cultured in microwell scaffolds for seven days showed insulin release and insulin content comparable to those of free-floating control islets. Islet morphology and insulin and glucagon expression were maintained during culture in the microwell scaffolds. Our results indicate that the microwell scaffold platform prevents islet aggregation by confinement of individual islets in separate microwells, preserves the islet's native rounded morphology, and provides a protective environment without impairing islet functionality, making it a promising platform for use in extrahepatic islet transplantation.

  1. Biodegradable PBAT/PLA Blend with Bioactive MCPA-PHBV Conjugate Suppresses Weed Growth.

    Science.gov (United States)

    Kwiecien, Iwona; Adamus, Grazyna; Jiang, Guozhan; Radecka, Iza; Baldwin, Timothy C; Khan, Habib R; Johnston, Brian; Pennetta, Valentina; Hill, David; Bretz, Inna; Kowalczuk, Marek

    2018-01-09

    The herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) conjugated with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was prepared via a melt transesterification route. The resultant bioactive oligomer was then mixed with a blend of polylactide (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) with different loadings to manufacture films to be used as a bioactive, biodegradable mulch to deliver the herbicide to target broadleaf weed species. The biological targeting of the MCPA-PHBV conjugate in the mulch film was investigated under glasshouse conditions using faba bean (Vicia faba) as a selective (nontarget) model crop species having broadleaf morphology. The presence of the MCPA-PHBV conjugate in the biodegradable PBTA/PLA blend was shown to completely suppress the growth of broadleaf weed species while displaying only a mild effect on the growth of the model crop. The degradation of the mulch film under glasshouse conditions was quite slow. The release of the MCPA-PHBV during this process was detected using NMR, GPC, EDS, and DSC analyses, indicating that the majority of the MCPA diffused out after MCPA-PHBV conjugate bond scission. These data provide a strong "proof of concept" and show that this biodegradable, bioactive film is a good candidate for future field applications and may be of wide agricultural applicability.

  2. Rheokinetic study of crosslinking of a,w-dihydroxy oligo(alkylene maleates with a trisisocyanate

    Directory of Open Access Journals (Sweden)

    NICOLAS SPASSKY

    2003-03-01

    Full Text Available The crosslinking reaction of three series of a,w-dihydroxy oligo(alkylene maleates with a trifunctional isocyanate was followed by dynamic mechanical analysis and FTIR spectroscopy. The evaluation of rheological parameters, such as storage G’ and loss modulus G", was recorded. A typical G’ versus time curve has a characteristic “S” shape, indicating autoacceleration of the crosslinking reaction. The whole curing process starting from G’ equal G" or the beginning of gelation is described by a second - order phenomenological rheokinetic equation which takes into account the autoacceleration effect, the latter being a consequence of the superposition of both the chemical reaction and phase segregation. It appears that the crosslinking reaction rate depends on the concentration of the functional groups, i.e., on the molecular weight of the polyester prepolymer and on the length of the aliphatic sequence in the repeating unit or the segmental mobility. The crosslinking rate decreases in the order: poly(octamethylene maleate > poly(hexamethylene maleate > poly(butylene maleate.

  3. Wetting of Hydrophilic Electrospun Mats Produced by Blending SEBS with PEO-PPO-PEO Copolymers of Different Molecular Weight.

    Science.gov (United States)

    Kurusu, Rafael S; Demarquette, Nicole R

    2016-02-23

    The interaction of electrospun mats with water is critical for many possible applications, and the water contact angle on the surface is the parameter usually measured to characterize wetting. Although useful for hydrophobic surfaces, this approach is limited for hydrophilic mats, where wicking also has to be considered. In this case, it is still unclear how the fiber surface chemical composition and morphology will affect the wetting behavior of electrospun mats. In this work, wetting was studied with different hydrophilic membranes produced by blending thermoplastic elastomer poly(styrene)-b-poly(ethylene-butylene)-b-poly(styrene) (SEBS) with amphiphilic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) molecules. Three different types of PEO-PPO-PEO, with different molar masses, PEO content, and physical form were used. The effect of these differences on the wetting behavior of the electrospun mats was evaluated by contact angle goniometry, wicking measurements, and different imaging techniques. X-ray photoelectron spectroscopy was used to characterize the surface chemical composition. The smaller molecules quickly saturated the surface at low concentrations, making the mats hydrophilic. The sheath of PEO-PPO-PEO also resulted in fast absorption of water, when comparing the saturated and nonsaturated surfaces. Longer PEO chain-ends seemed to hinder complete segregation and also led to a higher activation time when in contact with water. Liquid PEO-PPO-PEO was easily leached by water.

  4. Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

    Directory of Open Access Journals (Sweden)

    J. B. Olivato

    2013-01-01

    Full Text Available Blends of starch/polyester have been of great interest in the development of biodegradable packaging. A method based on multiple responses optimisation (Desirability was used to evaluate the properties of tensile strength, perforation force, elongation and seal strength of cassava starch/poly(butylene adipate-co-terephthalate (PBAT blown films produced via a one-step reactive extrusion using tartaric acid (TA as a compatibiliser. Maximum results for all the properties were set as more desirable, with an optimal formulation being obtained which contained (55:45 starch/PBAT (88.2 wt. (%, glycerol (11.0 wt. (% and TA (0.8 wt. (%. Biodegradable plastic bags were produced using the film with this formulation, and analysed according to the standard method of the Associação Brasileira de Normas Técnicas (ABNT. The bags exhibited a 45% failure rate in free-falling dart impact tests, a 10% of failure rate in dynamic load tests and no failure in static load tests. These results meet the specifications set by the standard. Thus, the biodegradable plastic bags fabricated with an optimised formulation could be useful as an alternative to those made from non-biodegradable materials if the nominal capacity declared for this material is considered.

  5. Biodegradable compounds: Rheological, mechanical and thermal properties

    Science.gov (United States)

    Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

    2015-12-01

    Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

  6. Isocyanate toughening of pCBT/organoclay nanocomposites with exfoliated structure and enhanced mechanical properties

    Directory of Open Access Journals (Sweden)

    T. Abt

    2014-12-01

    Full Text Available Cyclic butylene terephthalate (CBT® is an interesting matrix material for the preparation of nanocomposites due to its very low, water-like melt viscosity which favours clay exfoliation. Nevertheless, polymerized CBT (pCBT is inherently brittle. This paper reports the preparation of isocyanate-toughened nanocomposites made from CBT and organo-modified montmorillonite. The role of the organoclay as reinforcement and the polymeric isocyanate (PMDI as toughening agent on the properties of pCBT was studied. The organoclay increased the stiffness and strength by up to 20% whereas the PMDI improved the deformation behaviour. However, the PMDI did not affect the degree of clay dispersion or exfoliation and flocculated-intercalated structures were observed. The compatibility between the pCBT matrix and clay was further increased by preparing PMDI-tethered intercalated organoclay. The modified organoclay then exfoliated during ring-opening polymerization and yielded true pCBT/clay nanocomposites. This work demonstrates that reactive chain extension of CBT with a polyfunctional isocyanate is an effective method to obtain toughened pCBT nanocomposites. Moreover, isocyanates can enhance the compatibility between pCBT and nanofiller as well as the degree of exfoliation.

  7. Preparation and characterization of an aromatic polyester/polyaniline composite and its improved counterpart

    Directory of Open Access Journals (Sweden)

    C. S. Wu

    2012-06-01

    Full Text Available Poly(butylene terephthalate (PBT composites containing polyaniline (PANI were prepared using a melt-blending process. Maleic anhydride-grafted PBT (PBT-g-MA and PANI were used to improve the compatibility of PANI within the PBT matrix. PBT-g-MA/PANI composites exhibited noticeably superior mechanical properties compared with those of PBT/PANI due to greater compatibility with the added PANI. The antibacterial and antistatic properties of the composites were also evaluated. Escherichia coli were chosen as the standard bacteria for determining the antibacterial properties of the composite materials. The PBT-g-MA/PANI composites showed markedly enhanced antibacterial and antistatic properties compared to PBT/PANI composites due to the formation of imide bonds from condensation of the anhydride carboxyl acid groups of PBT-g-MA with the amino groups of PANI. The optimal level of PANI in the composites was 9 wt%, as excess PANI led to separation of the two organic phases, lowering their compatibility.

  8. Performance and environmental impact of biodegradable polymers as agricultural mulching films.

    Science.gov (United States)

    Touchaleaume, François; Martin-Closas, Lluís; Angellier-Coussy, Hélène; Chevillard, Anne; Cesar, Guy; Gontard, Nathalie; Gastaldi, Emmanuelle

    2016-02-01

    In the aim of resolving environmental key issues such as irreversible soil pollution by non-biodegradable and non-recoverable polyethylene (PE) fragments, a full-scale field experiment was set up to evaluate the suitability of four biodegradable materials based on poly(butylene adipate-co-terephtalate) (PBAT) to be used as sustainable alternatives to PE for mulching application in vineyard. Initial ultimate tensile properties, functional properties during field ageing (water vapour permeability and radiometric properties), biodegradability and agronomical performance of the mulched vines (wood production and fruiting yield) were studied. In spite of their early loss of physical integrity that occurred only five months after vine planting, the four materials satisfied all the requested functional properties and led to agronomic performance as high as polyethylene. In the light of the obtained results, the mulching material lifespan was questioned in the case of long-term perennial crop such as grapevine. Taking into account their mulching efficiency and biodegradability, the four PBAT-based studied materials are proven to constitute suitable alternatives to the excessively resistant PE material. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Synthesis and characterization of novel dimethacrylates of different chain lengths as possible dental resins.

    Science.gov (United States)

    Podgórski, Maciej

    2010-06-01

    In this study three novel dimethacrylates of different chain lengths having bulky bicycloaliphatic rings were synthesized and proposed as possible dental monomers for dental resin mixtures. The monomers were prepared by the reaction of glycidyl methacrylate with dicarboxylic acid esters obtained from nadic anhydride and ethylene, 1,4-butylene and 1,6-hexylene glycols. The addition reaction of glycidyl methacrylate and the acidic compound was carried out in the presence of basic catalyst-tetraethylammonium bromide. The monomers were photopolymerized in the presence of a photoinitiator which was 2,2-dimethoxy-2-phenyloacetophenone. Unfilled homopolymers were evaluated for photopolymerization conversion and volumetric curing shrinkage. Water sorption, water solubility, flexural strength and hardness were measured. The prepared polymers were also subjected to dynamic mechanical studies (DMA). The proposed dimethacrylates exhibit low curing shrinkage (about 4-5%) and high degree of double bond conversion (up to 84%). Their water sorption and water solubility are comparable to those of Bis-GMA composite resin. Furthermore, their thermo-mechanical properties are better than those of the commonly known dimethacrylates. The new dimethacrylates are promising photocurable dental monomers owning to simple synthesis, high degree of conversion coupled with low curing shrinkage and good mechanical properties. Copyright (c) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  10. Synthesis, structure and properties of thermoplastic poly(ester–siloxane elastomers

    Directory of Open Access Journals (Sweden)

    VESNA V. ANTIC

    2006-07-01

    Full Text Available Two series of thermoplastic poly(ester–siloxane elastomers (TPES, with hard segments based on poly(butylene terephthalate (PBT and soft segments based on poly(dimethylsiloxane (PDMS, were synthesized by high-temperature, two-step transesterification reaction in the melt. In series I, themass ratio of hard and soft segments was kept constant (57:43, while the length of the segments was varied, whereas in series II, the mass ratio of hard and soft segments was varied in range from 70:30 to 40:60, with a constant length of the soft segments. The segmented structure of the poly(ester–siloxane copolymers was verified by 1H-NMR spectroscopy of the soluble and insoluble fractions, obtained after extraction of the samples with chloroform. The influence of the structure and composition of the TPES on the melting temperatures and degrees of crystallinity was investigated by differential scanning calorimetry (DSC. The rheological properties were investigated by dynamic mechanical analysis (DMA.

  11. Rheological behaviour of thermoplastic poly(ester-siloxanes

    Directory of Open Access Journals (Sweden)

    Antić Vesna V.

    2010-01-01

    Full Text Available Two series of thermoplastic elastomers (TPES based on poly(dimethylsiloxane, (PDMS as the soft segment and poly(butylene terephthalate (PBT as the hard segment, were analyzed by dynamic mechanical spectroscopy. In the first TPES series the lengths of both hard and soft segments were varied while the mass ratio of the hard to soft segments was nearly constant (about 60 mass%. In the second series, the mass ratio of hard and soft segments was varied in the range from 60/40 to 40/60, with a constant length of soft PDMS segments. The influence of the structure and composition of TPESs on the rheological properties, such as complex dynamic viscosity, η*, the storage, G’, and loss, G”, shear modulus as well as the microphase separation transition temperature, TMST, was examined. The obtained results showed that the storage modulus of the TPESs increased in a rubbery plateau region with increasing degree of crystallinity. The rheological measurements of TPESs also showed that a microphase reorganization occurred during the melting process. The microphase separation transition temperatures were in the range from 220 to 234 °C. In the isotropic molten state, the complex dynamic viscosity increased with increasing both the content and lenght of hard PBT segments.

  12. Conditioned medium as a strategy for human stem cells chondrogenic differentiation.

    Science.gov (United States)

    Alves da Silva, M L; Costa-Pinto, A R; Martins, A; Correlo, V M; Sol, P; Bhattacharya, M; Faria, S; Reis, R L; Neves, Nuno M

    2015-06-01

    Paracrine signalling from chondrocytes has been reported to increase the synthesis and expression of cartilage extracellular matrix (ECM) by stem cells. The use of conditioned medium obtained from chondrocytes for stimulating stem cells chondrogenic differentiation may be a very interesting alternative for moving into the clinical application of these cells, as chondrocytes could be partially replaced by stem cells for this type of application. In the present study we aimed to achieve chondrogenic differentiation of two different sources of stem cells using conditioned medium, without adding growth factors. We tested both human bone marrow-derived mesenchymal stem cells (hBSMCs) and human Wharton's jelly-derived stem cells (hWJSCs). Conditioned medium obtained from a culture of human articular chondrocytes was used to feed the cells during the experiment. Cultures were performed in previously produced three-dimensional (3D) scaffolds, composed of a blend of 50:50 chitosan:poly(butylene succinate). Both types of stem cells were able to undergo chondrogenic differentiation without the addition of growth factors. Cultures using hWJSCs showed significantly higher GAGs accumulation and expression of cartilage-related genes (aggrecan, Sox9 and collagen type II) when compared to hBMSCs cultures. Conditioned medium obtained from articular chondrocytes induced the chondrogenic differentiation of MSCs and ECM formation. Obtained results showed that this new strategy is very interesting and should be further explored for clinical applications. Copyright © 2013 John Wiley & Sons, Ltd.

  13. Phase diagrams in blends of poly(3-hydroxybutyric acid with various aliphatic polyesters

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available Phase behavior with immiscibility, miscibility, crystalline morphology, and kinetic analysis in blends of poly(3-hydroxybutyric acid (PHB with aliphatic polyesters such as poly(butylene adipate (PBA, poly(ethylene adipate (PEA, poly(trimethylene adipate (PTA, or poly(ethylene succinate (PESu, respectively, were explored mainly using differential scanning calorimeter (DSC and polarized-light optical microscopy (POM. Immiscibility phase behavior with reversible upper-critical-solution-temperature (UCST is common in the PHB/polyester blends. The polyester/polyester blend of PHB/PTA is partially miscible with no UCST in melt and amorphous glassy states within a composition range of PTA less than 50 wt%. The miscible crystalline/crystalline blend exhibits ring-banded spherulites at Tc = 50~100°C, with inter-ring spacing dependent on Tc. All immiscible or partially miscible PHB/polyester blends, by contrast, exhibit disrupted ringbanded spherulites or discrete spherical phase domains upon cooling from UCST to crystallization. The blends of PHB with all other aliphatic polyesters, such as PESu, PEA, PBA, etc. are only partially miscible or immiscible with an upper critical solution temperature (UCST at 180~221°C depending on blend composition. UCST with reversibility was verified.

  14. Phase morphological study on SEBS compatibilized PS/LDPE blends

    Directory of Open Access Journals (Sweden)

    Chatchai Kunyawut

    2014-09-01

    Full Text Available The co-continuous phase morphology of polystyrene (PS/low density polyethylene (LDPE blends compatibilized with poly(styrene-block-ethylene/butylene-block-styrene triblock copolymers (SEBS with varying molecular weights has been investigated. The blend samples were prepared in a mini-twin screw extruder. The barrel length and diameter are 224 and 16 mm, respectively. The diameter of the capillary die is 1 mm. The concentration of the blends was 70/30 wt% of PS/LDPE while that of the SEBS used was 5 wt% of the blend. The mixing temperatures used were 180, 250, and 280o C, and a screw speed of 60 rpm. The morphology of the blends was investigated using an AFM technique. Average droplet diameters of the blend samples were determined using an OM technique. The co-continuous morphology has not been obtained in all the blends, although the mixing temperature used is as high as 280o C. The experimental results indicated that the model prediction of the co-continuous morphology proposed by Willemse and co-worker was not applicable to the blend systems studied. Only droplet-type dispersion was observed. This is considered to arise from the processing conditions and the mixing device used. The blend compatibilized with the high molecular weight SEBS had higher dispersed phase size than that of the blend compatibilized with the medium and low molecular weight SEBSs. This behaviour is likely to arise from coalescence during melt processing.

  15. Isolation and screening of biopolymer-degrading microorganisms from northern Thailand.

    Science.gov (United States)

    Penkhrue, Watsana; Khanongnuch, Chartchai; Masaki, Kazuo; Pathom-Aree, Wasu; Punyodom, Winita; Lumyong, Saisamorn

    2015-09-01

    Forty agricultural soils were collected from Chiang Mai and Lampang provinces in northern Thailand. Bacteria, actinomycetes and fungi were isolated and screened for their ability to degrade polylactic acid (PLA), polycaprolactone (PCL) and poly(butylene succinate) (PBS) by the agar diffusion method. Sixty-seven actinomycetes, seven bacteria and five fungal isolates were obtained. The majority of actinomycetes were Streptomyces based on morphological characteristic, chemotaxonomy and 16S rRNA gene data. Seventy-nine microorganisms were isolated from 40 soil samples. Twenty-six isolates showed PLA-degradation (32.9 %), 44 isolates showed PBS-degradation (55.7 %) and 58 isolates showed PCL-degradation (73.4 %). Interestingly, 16 isolates (20.2 %) could degrade all three types of bioplastics used in this study. The Amycolatopsis sp. strain SCM_MK2-4 showed the highest enzyme activity for both PLA and PCL, 0.046 and 0.023 U/mL, respectively. Moreover, this strain produced protease, esterase and lipase on agar plates. Approximately, 36.7 % of the PLA film was degraded by Amycolatopsis sp. SCM_MK2-4 after 7 days of cultivation at 30 °C in culture broth.

  16. Potential fungal inhibition by immobilized hydrolytic enzymes from Trichoderma asperellum.

    Science.gov (United States)

    Silva, Bárbara Dumas S; Ulhoa, Cirano J; Batista, Karla A; Yamashita, Fábio; Fernandes, Kátia F

    2011-08-10

    The use of cell wall degrading enzymes from Trichoderma asperellum immobilized on biodegradable support is an alternative for food packaging. In this study, hydrolytic enzymes produced by T. asperellum were tested as a fungal growth inhibitor, in free form or immobilized on a biodegradable film composed of cassava starch and poly(butylene adipate-co-terephtalate) (PBAT). The inhibitory activity was tested against Aspergillus niger , Penicillium sp., and Sclerotinia sclerotiorum , microorganisms that frequently degrade food packaging. The use of chitin as carbon source in liquid medium induced T. asperellun to produce N-acetylglucosaminidase, β-1,3-glucanase, chitinase, and protease. The presence of T. asperellun cell wall degradating enzymes (T-CWD) immobilized by adsorption or covalent attachment resulted in effective inhibition of fungal growth. The enzymatic activity of T-CWD was stronger on S. sclerotiorum than on the Aspergillus or Penicillum isolates tested. These results suggest that T-CWD can be used in a free or immobilized form to suppress fungi that degrade food packaging.

  17. Effects of different level addition of zeolite ZSM-5 additive on quality and composition of the dry gas, LPG (Liquefied Petroleum Gas) and gasoline, produced in FCC (Fluid Catalytic Cracking); Efeito dos diferentes niveis de adicao de aditivos de ZSM-5 na qualidade e composicao do gas combustivel, GLP e gasolina produzidos em FCC

    Energy Technology Data Exchange (ETDEWEB)

    Bastiani, Raquel; Pimenta, Ricardo D.M.; Almeida, Marlon B.B.; Lau, Lam Y. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The effects of the addition of different level of ZSM-5 additives on different FCC catalysts formulations have been studied on laboratory scale FST (Fluidized Simulation Test). The main objective of the present work is to perform a qualitative identification of the main parameters of FCC catalyst which affect the ZSM-5 additives performance concerning quality and composition of Dry Gas, LPG and Gasoline. The product composition of each test was analyzed by PIANO groups separated by carbon number. The effect of ZSM-5 on products composition was evaluated. The results showed that the ZSM-5 additive cracks gasoline range olefins and isoparaffins into Dry Gas and LPG, favoring the formation of ethylene, propylene and butylenes, while the absolute yield of gasoline aromatics changes little. The aromatics fraction in gasoline, MON and RON numbers in gasoline increase. The ZSM-5 effectiveness is negatively affected by high levels of rare earth on FCC catalyst (RE-USY). Higher hydrogen transfer provides lower olefins (higher than C6) formation, which are the most reactive species for ZSM-5 cracking. (author)

  18. Maximizing light olefins production in fluid catalytic cracking (FCC) units; Maximizacao de olefinas leves em unidades de craqueamento catalitico fluido

    Energy Technology Data Exchange (ETDEWEB)

    Pimenta, Ricardo D.M.; Pinho, Andrea de Rezende [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The Fluid Catalytic Cracking (FCC) process is widely spread over the ten PETROBRAS refineries in its thirteen industrial units. The importance of the FCC process resides on its high gasoline output, being the main supplier of this important product to the system. Additionally, FCC process is the main source of light hydrocarbons in the LPG range, including light olefins. The increasing demand for ethylene, propylene and butylenes was encouraging to concentrate the research efforts on studies about alternatives for the traditional FCC process. In the present work, the proposals from main licensors (UOP, KBR, Stone and Webster) for a light-olefins-driven FCC process (Petrochemical FCC) will be compared. Furthermore, the catalytic route for light olefins production in FCC units is also described. An additive based on ZSM- 5 zeolite, which is produced following a PETROBRAS proprietary technology, is being largely applied into the catalyst inventories of all FCC units. An analysis of different scenarios was performed to estimate the maximum potential of light olefins production from the highest possible ZSM-5 additive usage. More specifically for the case of ethylene, which production is also boosted by the same type of additive, studies are being conducted with the objective of recovering it from a C2 stream using specific units to do the splitting (UPGR). The search for increasing light olefins production in the refining processes is in line with PETROBRAS strategic plan which targeted for the company a more intense activity in the Brazilian petrochemical market (author)

  19. Anticancer activity of newly synthesized azaphenothiazines from NCI's anticancer screening bank.

    Science.gov (United States)

    Pluta, Krystian; Jeleń, Małgorzata; Morak-Młodawska, Beata; Zimecki, Michał; Artym, Jolanta; Kocieba, Maja

    2010-01-01

    The activity of the newly synthesized azaphenothiazines: tricyclic 10-substituted dipyridothiazines 1-9, pentacyclic 6-substituted diquinothiazines 10-22 and hexacyclic diquinothiazinium salt 23 was tested on 55-60 in vitro cell lines. The cell lines included nine types of cancer: leukemia, non-small cell lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer and breast cancer (National Cancer Institute, Bethesda, MD, USA). The features of the chemical substituent at the thiazine nitrogen atom confer the anticancer activity of diquinothiazines 10-23. Unexpectedly, the most active of the dipyridothiazines 1-9 was the unsubstituted compound 1 (the substituent is a hydrogen atom). The most cytotoxic compound was the half-mustard derivative 18. The GI(50) value of this compound was -7.06 (corresponding to 40 ng/ml) when tested on the melanoma cell line SK-MEL-5 and -6.0 - -6.62 using cell lines from various cancers including: leukemia (CCRF-CEM), the MOLT-4 cell line, colon cancer (HCT-116), central nervous system cancer (SNB-75 and SF-295), prostate cancer (PC-3), non-small cell lung cancer (NCI-H460 and HOP-92), ovarian cancer (IGROV1 and OVCAR-4) and breast cancer (MDA-MB-460). The ethylene group in the aminoalkylazaphenothiazines is as a good linker and is similar to the propylene and butylene linkers in aminoalkylphenothiazines. To our knowledge, this is the first demonstration of significant azaphenothiazine anticancer activity.

  20. Comparative Studies on Thermal, Mechanical, and Flame Retardant Properties of PBT Nanocomposites via Different Oxidation State Phosphorus-Containing Agents Modified Amino-CNTs

    Directory of Open Access Journals (Sweden)

    San-E Zhu

    2018-01-01

    Full Text Available High-performance poly(1,4-butylene terephthalate (PBT nanocomposites have been developed via the consideration of phosphorus-containing agents and amino-carbon nanotube (A-CNT. One-pot functionalization method has been adopted to prepare functionalized CNTs via the reaction between A-CNT and different oxidation state phosphorus-containing agents, including chlorodiphenylphosphine (DPP-Cl, diphenylphosphinic chloride (DPP(O-Cl, and diphenyl phosphoryl chloride (DPP(O3-Cl. These functionalized CNTs, DPP(Ox-A-CNTs (x = 0, 1, 3, were, respectively, mixed with PBT to obtain the CNT-based polymer nanocomposites through a melt blending method. Scanning electron microscope observations demonstrated that DPP(Ox-A-CNT nanoadditives were homogeneously distributed within PBT matrix compared to A-CNT. The incorporation of DPP(Ox-A-CNT improved the thermal stability of PBT. Moreover, PBT/DPP(O3-A-CNT showed the highest crystallization temperature and tensile strength, due to the superior dispersion and interfacial interactions between DPP(O3-A-CNT and PBT. PBT/DPP(O-A-CNT exhibited the best flame retardancy resulting from the excellent carbonization effect. The radicals generated from decomposed polymer were effectively trapped by DPP(O-A-CNT, leading to the reduction of heat release rate, smoke production rate, carbon dioxide and carbon monoxide release during cone calorimeter tests.

  1. Interaction of the organic tin chloride with the liquid model membranes

    Energy Technology Data Exchange (ETDEWEB)

    Podolak, M; Engel, G; Man, D [Institute of Physics, Opole University, Oleska 48, 45-052 Opole (Poland)

    2007-08-15

    The objective of the work was to investigate the effect of organic tin chloride (C{sub 3}H{sub 7}){sub 3}SnCl on the electric parameters of membranes in the form of filters of the company Synpor (Czech Republic) impregnated with various fatty acids, dissolved with carbon tetrachloride (CCl{sub 4}). Three carboxylic acids were used in the study: palmitic, arachidic and oleic, and dissolvent of the acids (CCl{sub 4}) as well as butylene ester of lauric acid. In all cases, introduction of tin chloride of constant concentration amounting to 0.15 mM to the measurement chamber resulted in induction of membrane voltage. In case of pure lauric acid and CCl{sub 4}, the voltage reached the maximum value and then decreased to a certain constant value. In the case of all acids dissolved in CCl{sub 4}, the voltage increased only up to a certain constant value. Voltage drop (below the value) was observed after application of appropriately high concentration of tin chloride, in case of membranes impregnated with the mixture of lauric acid ester with CCl{sub 4} and palmitic acid with CCl{sub 4}. The study also demonstrated that electrical resistance of membranes impregnated with carboxylic acid increased in the presence of tin chloride and decreased in case of membranes impregnated with lauric acid ester. However, electric capacities of membranes did not significant change.

  2. Effect of Organic Tin Compounds on Electric Properties of Model Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Podolak, M.; Engel, G.; Man, D. [Inst. of Physics, Opole Univ., Opole (Poland)

    2006-05-15

    The objective of the present work was to investigate the effect of selected organic tin compounds and potassium chloride (used as a reference substance) on the trans-membrane electric voltage and electric resistance of model membranes, the latter being nitrocellulose filters impregnated with butylene ester of lauric acid. The increasing KCl concentration (in the measurement chambers) caused a rapid rise of the negative trans-membrane voltage, whose value stabilized afterwards. In the case of (C{sub 3}H{sub 7}){sub 3}SnCl an abrupt maximum of the negative voltage was observed followed by a monotonic drop to zero. In the case of highest concentrations of this compound the voltages, after having reached zero, changed their polarization to the opposite. Within the range of small concentrations two slight voltage maxima were observed. Non-ionic tin compounds like (CH{sub 3}){sub 4}Sn and (C{sub 2}H{sub 5}){sub 4}Sn had an insignificant influence on the electric properties of the studied membranes. (orig.)

  3. Waterborne Polyurethane Coatings with Covalently Linked Black Dye Sudan Black B

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2017-10-01

    Full Text Available Colored waterborne polyurethanes have been widely used in paintings, leathers, textiles, and coatings. Here, a series of black waterborne polyurethanes (WPUs with different ratios of black dye, Sudan Black B (SDB, were prepared by step-growth polymerization. WPU emulsions as obtained exhibit low particle sizes and remarkable storage stability at the same time. At different dye loadings, essential structural, statistical and thermal properties are characterized. FTIR (fourier transform infrared spectra indicate that SDB is covalently linked into waterborne polyurethane chains. All of the WPUs with covalently linked SDB show better color fastness and resistance of thermal migration than those with SDB mixed physically. Besides, WPUs incorporated SDB covalently with different polymeric diols, polytetramethylene ether glycol (PTMG, polypropylene glycol (PPG, poly-1, 4-butylene adipate glycol (PBA and polycaprolactone glycol (PCL, were prepared to obtain different properties to cater to a variety of practical demands. By a spraying method, the black WPUs can be directly used as metal coatings without complex dyeing process by simply mixing coating additive and other waterborne resins, which exhibit excellent coating performance.

  4. Significant Enhancement of Mechanical and Thermal Properties of Thermoplastic Polyester Elastomer by Polymer Blending and Nanoinclusion

    Directory of Open Access Journals (Sweden)

    Manwar Hussain

    2016-01-01

    Full Text Available Thermoplastic elastomer composites and nanocomposites were fabricated via melt processing technique by blending thermoplastic elastomer (TPEE with poly(butylene terephthalate (PBT thermoplastic and also by adding small amount of organo modified nanoclay and/or polytetrafluoroethylene (PTFE. We study the effect of polymer blending on the mechanical and thermal properties of TPEE blends with and without nanoparticle additions. Significant improvement was observed by blending only TPEE and virgin PBT polymers. With a small amount (0.5 wt.% of nanoclay or PTFE particles added to the TPEE composite, there was further improvement in both the mechanical and thermal properties. To study mechanical properties, flexural strength (FS, flexural modulus (FM, tensile strength (TS, and tensile elongation (TE were all investigated. Thermogravimetric analysis (TGA and differential scanning calorimetry (DSC were used to analyze the thermal properties, including the heat distortion temperature (HDT, of the composites. Scanning electron microscopy (SEM was used to observe the polymer fracture surface morphology. The dispersion of the clay and PTFE nanoparticles was confirmed by transmission electron microscopy (TEM analysis. This material is proposed for use as a baffle plate in the automotive industry, where both high HDT and high modulus are essential.

  5. Experimental and One-Dimensional Mathematical Modeling of Different Operating Parameters in Direct Formic Acid Fuel Cells

    Directory of Open Access Journals (Sweden)

    Shingjiang Jessie Lue

    2017-11-01

    Full Text Available The purpose of this work is to develop a one-dimensional mathematical model for predicting the cell performance of a direct formic acid fuel cell and compare this with experimental results. The predicted model can be applied to direct formic acid fuel cells operated with different formic acid concentrations, temperatures, and with various electrolytes. Tafel kinetics at the electrodes, thermodynamic equations for formic acid solutions, and the mass-transport parameters of the reactants are used to predict the effective diffusion coefficients of the reactants (oxygen and formic acid in the porous gas diffusion layers and the associated limiting current densities to ensure the accuracy of the model. This model allows us to estimate fuel cell polarization curves for a wide range of operating conditions. Furthermore, the model is validated with experimental results from operating at 1–5 M of formic acid feed at 30–80 °C, and with Nafion-117 and silane-crosslinked sulfonated poly(styrene-ethylene/butylene-styrene (sSEBS membrane electrolytes reinforced in porous polytetrafluoroethylene (PTFE. The cell potential and power densities of experimental outcomes in direct formic acid fuel cells can be adequately predicted using the developed model.

  6. Mechanical and thermal properties of PP/PBT blends compatibilized with triblock thermoplastic elastomer

    Directory of Open Access Journals (Sweden)

    Ignaczak Wojciech

    2015-09-01

    Full Text Available A linear triblock copolymer, poly(styrene-b-etylene/butylene-b-styrene(SEBS thermoplastic elastomer (TPE grafted with maleic anhydride was used for compatibilization of PP/PBT blends. PP/PBT blends of different mass ratios 60/40, 50/50, 40/60 were mixed with 2.5, 5.0 and 7.5 wt.% of SEBS copolymer in a twin screw extruder. Differential scanning calorimetry and dynamic mechanical analysis were performed to define the phase structure of PP/PBT blends. TPE with a rubbery mid-block shifted the glass transition of PP/PBT blend towards lower temperatures, and significant decrease the crystallization temperature of a crystalline phase of PP component was observed. The influence of the amount of compatibilizer and the blend composition on the mechanical properties (tensile and flexural strengths, toughness and moduli was determined. Addition of 5 wt.% of a triblock TPE led to a three-fold increase of PP/PBT toughness. A significant increase of impact properties was observed for all materials compatibilized with the highest amount of SEBS copolymer.

  7. Application of polymer nanocomposites in the nanomedicine landscape: envisaging strategies to combat implant associated infections.

    Science.gov (United States)

    Dwivedi, Poushpi; Narvi, Shahid S; Tewari, Ravi P

    2013-12-16

    This review article presents an overview of the potential biomedical application of polymer nanocomposites arising from different chemistries, compositions, and constructions. The interaction between the chosen matrix and the filler is of critical importance. The existing polymer used in the biomedical arena includes aliphatic polyesters such as polylactide (PLA), poly(ε-caprolactone) (PCL), poly(p-dioxanone) (PPDO), poly(butylenes succinate) (PBS), poly(hydroxyalkanoate)s, and natural biopolymers such as starch, cellulose, chitin, chitosan, lignin, and proteins. The nanosized fillers utilized to fabricate the nanocomposites are inorganic, organic, and metal particles such as clays, magnetites, hydroxyapatite, nanotubes chitin whiskers, lignin, cellulose, Au, Ag, Cu, etc. These nanomaterials are taking root in a variety of diverse healthcare applications in the sector of nanomedicine including the domain of medical implants and devices. Despite sterilization and aseptic procedures the use of these biomedical devices and prosthesis to improve the patient's 'quality of life' is facing a major impediment because of bacterial colonization causing nosocomial infection, together with the multi-drug-resistant 'super-bugs' posing a serious threat to its utility. This paper discusses the current efforts and key research challenges in the development of self-sterilizing nanocomposite biomaterials for potential application in this area.

  8. Comparison of primary monoatomic with primary polyatomic ions for the characterisation of polyesters with static secondary ion mass spectrometry.

    Science.gov (United States)

    Van Royen, Pieter; Taranu, Anca; Van Vaeck, Luc

    2005-01-01

    Static secondary ion mass spectrometry (S-SIMS) emerges as one of the most adequate methods for the surface characterisation of polymers with an information depth of essentially one monolayer. The continuing search for increased analytical sensitivity and specificity has led to exploring the use of polyatomic primary ions as an alternative to the traditionally applied monoatomic projectiles. As part of a systematic investigation on polyatomic bombardment of organic and inorganic solids, this paper focuses on selected polyesters. Mass spectra and ion yields are compared for layers deposited on silicon wafers by spincoating solutions with different concentrations of poly(epsilon-caprolactone) (PCL), poly(butylene adipate) (PBA) and poly(ethylene adipate) (PEA). Accurate mass measurements have been used to support the assignment of the ions and link the composition of the detected ions to the analyte structure. Use of polyatomic projectiles increases the yield of structural ions with a factor of +/-15, +/-30 and +/-10 for PCL, PBA and PEA, respectively, in comparison to bombardment with Ga+ primary ions, while the molecular specificity is improved by the detection of additional high m/z ions. Copyright 2005 John Wiley & Sons, Ltd.

  9. Study of Syngas Conversion to Light Olefins by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Hossein Atashi

    2013-01-01

    Full Text Available The effect of adding MgO to a precipitated iron-cobalt-manganese based Fischer-Tropsch synthesis (FTS catalyst was investigated via response surface methodology. The catalytic performance of the catalysts was examined in a fixed bed microreactor at a total pressure of 1–7 bar, temperature of 280–380°C, MgO content of 5–25% and using a syngas having a H2 to CO ratio equal to 2.The dependence of the activity and product distribution on MgO content, temperature, and pressure was successfully correlated via full quadratic second-order polynomial equations. The statistical analysis and response surface demonstrations indicated that MgO significantly influences the CO conversion and chain growth probability as well as ethane, propane, propylene, butylene selectivity, and alkene/alkane ratio. A strong interaction between variables was also evidenced in some cases. The decreasing effect of pressure on alkene to alkane ratio is investigated through olefin readsorption effects and CO hydrogenation kinetics. Finally, a multiobjective optimization procedure was employed to calculate the best amount of MgO content in different reactor conditions.

  10. Improving the circular economy via hydrothermal processing of high-density waste plastics.

    Science.gov (United States)

    Helmer Pedersen, Thomas; Conti, Federica

    2017-10-01

    Rising environmental concerns on climate changes are causing an increasing attention on circular economies. The plastic economy, in particular, is in focus due to the accelerating consumption of plastics, mainly derived from virgin feedstock, combined with the lack of plastic recycling strategies. This work presents a novel outlook on the potential of using supercritical hydrothermal processing of waste plastic fractions for tertiary recycling. The study investigates hydrothermal processing of nine different, high-density types of plastics into original resin monomers and other value-added chemical compounds. The outlook presents conversion yields, carbon balances, and chemical details on the products obtained. It is found that all the investigated resins are prone to hydrothermal treatment, and that high yields of monomers and high value compounds (up to nearly 100%), suitable for chemicals and fuels applications, can be obtained. For instance, for polycarbonate, styrene-butadiene, poly(lactic acid), poly(ethylene terephthalate), and poly(butylene terephthalate), original monomeric compounds can be reclaimed for manufacturing new resins. The promising results presented demonstrate that hydrothermal processing of high-density plastics is a prospective technology for increasing the circularity of the plastic economy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Mutational analysis of cutinase-like enzyme, Cut190, based on the 3D docking structure with model compounds of polyethylene terephthalate.

    Science.gov (United States)

    Kawabata, Takeshi; Oda, Masayuki; Kawai, Fusako

    2017-07-01

    The cutinase-like enzyme, Cut190, from Saccharomonospora viridis AHK190 can degrade the inner block of polyethylene terephthalate (PET) in the presence of Ca(2+), and its mutant, S226P/R228S, exhibited increased activity and higher thermostability. The crystal structures of the Cut190 S226P mutant in the absence and presence of Ca(2+) were determined, and revealed the large conformational change induced upon Ca(2+) binding. However, the substrate-bound 3D structures of Cut190 remained unknown. In this study, to determine the substrate-binding site and improve the enzyme activity, we first built 3D structures of a PET model compound bound to the crystal structures, using the distance restraints between the scissile carbonyl group of the compound and the catalytic site of the enzyme. We then mutated the putative substrate-binding site predicted from the models, and experimentally determined the enzymatic activities of the mutants for the model substrate poly(butylene succinate-co-adipate). The mutated sites with decreased activity were consistent with the putative binding sites predicted by the 3D model from the Ca(2+)-bound crystal structure, suggesting that the structure of the Ca(2+)-bound state represents the active state. Notably, we generated two mutants with significantly increased activities. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  12. Biological production of functional chemicals from renewable resources

    Energy Technology Data Exchange (ETDEWEB)

    Tokiwa, Y.; Calabia, B.P. [National Inst. of Advanced Industrial Science and Technology, Tsukuba (Japan)

    2008-06-15

    The biological conversion of biomass into commodity and specialty chemicals is gaining interest due to an increased awareness of the impacts of greenhouse gases (GHGs) on the environment. New processing techniques for renewable feedstocks must be developed in order to facilitate the shift from fossil fuels to renewable energy sources. This article reviewed developments for renewable feedstocks for the production of multifunctional chemicals. Biotechnological methods of replacing chemical processes were outlined, including the fermentative production of lactic acid, as well as the production of bio-materials for use as monomers in plastics, lactic acid for polylactide (PLA), (R)-3-hydroxybutyric acid (R-3HB), poly(R)-3-hydroxybutyrate (PHB) and poly(butylene succinate) (PBS). Studies on lactic acid production and methods of developing effective substrates for biochemical production were reviewed along with mechanisms related to acid tolerance. The distribution of lactic acid bacteria (LAB) was discussed together with methods of increasing lactic acid concentrations. The article also reviewed species of microorganisms capable of producing significant amounts of functional chemicals. 54 refs., 2 tabs., 7 figs.

  13. Electron beam damage in high temperature polymers

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. (Dayton Univ., OH (USA). Research Inst.); Adams, W.W. (Air Force Materials Lab., Wright-Patterson AFB, OH (USA))

    1990-01-01

    Electron microscopic studies of polymers are limited due to beam damage. Two concerns are the damage mechanism in a particular material, and the maximum dose for a material before damage effects are observed. From the knowledge of the dose required for damage to the polymer structure, optimum parameters for electron microscopy imaging can be determined. In the present study, electron beam damage of polymers has been quantified by monitoring changes in the diffraction intensity as a function of electron dose. The beam damage characteristics of the following polymers were studied: poly(p-phenylene benzobisthiazole) (PBZT); poly(p-phenylene benzobisoxazole) (PBO); poly(benzoxazole) (ABPBO); poly(benzimidazole) (ABPBI); poly(p-phenylene terephthalamide) (PPTA); and poly(aryl ether ether ketone) (PEEK). Previously published literature results on polyethylene (PE), polyoxymethylene (POM), nylon-6, poly(ethylene oxide) (PEO), PBZT, PPTA, PPX, iPS, poly(butylene terephthalate) (PBT), and poly(phenylene sulphide) (PPS) were reviewed. This study demonstrates the strong dependence of the electron beam resistivity of a polymer on its thermal stability/melt temperature. (author).

  14. Functional groups grafted nonwoven fabrics for blood filtration-The effects of functional groups and wettability on the adhesion of leukocyte and platelet

    Science.gov (United States)

    Yang, Chao; Cao, Ye; Sun, Kang; Liu, Jiaxin; Wang, Hong

    2011-01-01

    In this work, the effects of grafted functional groups and surface wettability on the adhesion of leukocyte and platelet were investigated by the method of blood filtration. The filter materials, poly(butylene terephthalate) nonwoven fabrics bearing different functional groups including hydroxyl (OH), carboxyl (COOH), sulfonic acid group (SO3H) and zwitterionic sulfobetaine group (⊕N((CH3)2)(CH2)3SO3⊖) with controllable wettability were prepared by UV radiation grafting vinyl monomers with these functional groups. Our results emphasized that both surface functional groups and surface wettability had significant effects on the adhesion of leukocyte and platelet. In the case of filter materials with the same wettability, leukocytes adhering to filter materials decreased in the order: the surface bearing OH only > the surface bearing both OH and COOH > the surface bearing sulfobetaine group > the surface bearing SO3H, while platelets adhering to filter materials decreased as the following order: the surface bearing SO3H > the surface bearing both OH and COOH > the surface bearing OH only > the surface bearing sulfobetaine group. As the wettability of filter materials increased, both leukocyte and platelet adhesion to filter materials declined, except that leukocyte adhesion to the surface bearing OH only remained unchanged.

  15. Effect of reinforcement nanoparticles addition on mechanical properties of SBS/curaua fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Borba, Patricia M. [Servico Nacional de Aprendizagem Industrial (CETEPO/SENAI/RS), Sao Leopoldo, RS (Brazil). Centro Tecnologico de Polimeros; Tedesco, Adriana [Braskem S. A., III Polo Petroquimico, Triunfo, RS (Brazil); Lenz, Denise M., E-mail: denise.lenz@gmail.com [Universidade Luterana do Brasil (ULBRA), Canoas, RS (Brazil). Programa de Pos-graduacao em Engenharia de Materiais e Processos Sustentaveis

    2014-03-15

    Composites of styrene-butadiene-styrene triblock copolymer (SBS) matrix with curauá fiber and/or a nanoparticulated mineral (montmorillonite clay - MMT) used as reinforcing agents were prepared by melt-mixing. The influence of clay addition on properties like tensile and tear strength, rebound resilience, flex fatigue life, abrasion loss, hardness and water absorption of composites with 5, 10 and 20 wt% of curauá fiber was evaluated in presence of maleic anhydride grafted styrene-(ethylene-co-butylene)-styrene triblock copolymer (MA-g-SEBS) coupling agent. Furthermore, the effect of mineral plasticizer loading on tensile strength of selected composites was investigated. The hybrid SBS composite that showed the best overall mechanical performance was composed by 2 wt% of MMT and 5 wt% of curauá fiber. Increasing fiber content up to 20 wt% resulted in a general decrease in all mechanical properties as well as incorporation of 5 wt% MMT caused a decrease in the tensile strength in all fiber contents. The hybrid composites showed clay agglomerates (tactoids) poorly dispersed that could explain the poor mechanical performance of composites at higher concentrations of curauá fiber and MMT nanoparticles. The addition of plasticizer further decreased the tensile strength while the addition of MMT nanoparticles decreased water absorption for all SBS composites. (author)

  16. Synthesis and characterization of biodegradable aliphatic copolyesters with hydrophilic soft segments

    Directory of Open Access Journals (Sweden)

    JASNA DJONLAGIC

    2004-12-01

    Full Text Available In this study, the synthesis, structure and physical properties of two series of segmented poly(ester-ethers based on poly(butylene succinate and two different types of polyethers were investigated. The poly(ester-ethers were synthesized by transesterification reaction of dimethyl succinate, 1,4-butanediol and poly(ethylene oxide (PEO, Mn = 1000 g/mol in the first series, and poly(tetramethylene oxide (PTMO, Mn = 1000 g/mol in the second. The mass fraction of soft segments was varied between 10 and 50 mass. %. The effect of the introduction of two different polyether soft segments on the structure, thermal and rheological properties were investigated. The composition of the poly(ester-ethers, determined from their 1H-NMR spectra, showed that incorporation of soft polyether segments was successfully performed by the transesterification reaction in bulk. The molecular weight was estimated from solution viscosity measurements and complex dynamic viscosities. The thermal properties investigated by DSC indicated that the presence of soft segments lowers the melting and crystallization temperature of the hard phase, as well as the degree of crystallinity. Dynamical mechanical analysis was used to investigate the influence of composition on the rheological behavior of the segmented poly(ester-ethers. The results obtained from an enzymatic degradation test performed on some of the synthesized polymers showed that the biodegradability is enhanced with increasing hydrophilicity.

  17. Fatigue damage mechanisms in short fiber reinforced PBT+PET GF30

    Energy Technology Data Exchange (ETDEWEB)

    Klimkeit, B. [Institut PPRIME, CNRS, Universite de Poitiers, ENSMA, UPR 3346, Departement Physique et Mecanique des Materiaux, ENSMA, Teleport 2, 1 Avenue Clement Ader, BP 40109, 86961 Futuroscope Chasseneuil Cedex (France); RENAULT Technocentre, Material Engineering Department, TCR LAB 035, 1 avenue du Golf, 78288 Guyancourt Cedex (France); Castagnet, S. [Institut PPRIME, CNRS, Universite de Poitiers, ENSMA, UPR 3346, Departement Physique et Mecanique des Materiaux, ENSMA, Teleport 2, 1 Avenue Clement Ader, BP 40109, 86961 Futuroscope Chasseneuil Cedex (France); Nadot, Y., E-mail: yves.nadot@ensma.fr [Institut PPRIME, CNRS, Universite de Poitiers, ENSMA, UPR 3346, Departement Physique et Mecanique des Materiaux, ENSMA, Teleport 2, 1 Avenue Clement Ader, BP 40109, 86961 Futuroscope Chasseneuil Cedex (France); Habib, A. El; Benoit, G. [Institut PPRIME, CNRS, Universite de Poitiers, ENSMA, UPR 3346, Departement Physique et Mecanique des Materiaux, ENSMA, Teleport 2, 1 Avenue Clement Ader, BP 40109, 86961 Futuroscope Chasseneuil Cedex (France); Bergamo, S.; Dumas, C.; Achard, S. [RENAULT Technocentre, Material Engineering Department, TCR LAB 035, 1 avenue du Golf, 78288 Guyancourt Cedex (France)

    2011-01-25

    Research highlights: {yields} Final macroscopic cracking only affects the few last percent of the lifetime {yields} Classical approach based on fracture surface observation is not sufficient to characterize micro-mechanisms {yields} Different techniques (scanning electron microscopy, replica technique, infra-red imaging) are compared to the macroscopic mechanical behavior evolution (stiffness, viscous damping, ratcheting effect) {yields} The influence of surrounding fibers on some observed damage processes is being evidenced for the first time. - Abstract: The fatigue damage of a glass-reinforced PolyButylene Terephthalate and PolyEthylene Terephthalate with the fiber volume fraction of 30% (PBT+PET GF30) is investigated by means of various techniques. Fatigue tests at R = 0.1 are carried out on dogbone specimens and tubular specimens with different fiber orientations. The macroscopic evolution of the material behavior is evaluated and fatigue damage mechanisms are observed with a replica technique, Infrared imaging and scanning electron microscopy. A fatigue damage scenario is finally proposed. It is shown that the propagation of a single macroscopic crack is not the major fatigue mechanism under fatigue loading. Damage is spatially distributed in the material and the classical circular crack at the end of the fiber is confirmed as the based fatigue mechanisms. It is also shown that the damage observed alongside the fibers is related to spatial distribution of fiber rather than stress distribution around one single fiber.

  18. Functional groups grafted nonwoven fabrics for blood filtration-The effects of functional groups and wettability on the adhesion of leukocyte and platelet

    Energy Technology Data Exchange (ETDEWEB)

    Yang Chao [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Cao Ye [Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu 610081 (China); Sun Kang, E-mail: ksun@sjtu.edu.cn [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Liu Jiaxin; Wang Hong [Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu 610081 (China)

    2011-01-15

    In this work, the effects of grafted functional groups and surface wettability on the adhesion of leukocyte and platelet were investigated by the method of blood filtration. The filter materials, poly(butylene terephthalate) nonwoven fabrics bearing different functional groups including hydroxyl (OH), carboxyl (COOH), sulfonic acid group (SO{sub 3}H) and zwitterionic sulfobetaine group ({sup +}N((CH{sub 3}){sub 2})(CH{sub 2}){sub 3}SO{sub 3}{sup Circled-Minus }) with controllable wettability were prepared by UV radiation grafting vinyl monomers with these functional groups. Our results emphasized that both surface functional groups and surface wettability had significant effects on the adhesion of leukocyte and platelet. In the case of filter materials with the same wettability, leukocytes adhering to filter materials decreased in the order: the surface bearing OH only > the surface bearing both OH and COOH > the surface bearing sulfobetaine group > the surface bearing SO{sub 3}H, while platelets adhering to filter materials decreased as the following order: the surface bearing SO{sub 3}H > the surface bearing both OH and COOH > the surface bearing OH only > the surface bearing sulfobetaine group. As the wettability of filter materials increased, both leukocyte and platelet adhesion to filter materials declined, except that leukocyte adhesion to the surface bearing OH only remained unchanged.

  19. Caracterização de géis termorreversíveis de SEBS Characterization of thermoreversible gels of SEBS

    Directory of Open Access Journals (Sweden)

    Antonio José F. Carvalho

    2000-03-01

    Full Text Available RESUMO: Géis termorreversíveis preparados a partir de um copolímero em bloco de estireno - etileno/butileno - estireno (SEBS e polietileno de baixa densidade dissolvidos em óleos minerais parafínicos e óleos polibutênicos, bem como em suas misturas, foram preparados e caracterizados por calorimetria diferencial de varredura (DSC e análise dinâmico mecânica (DMA. Os termogramas obtidos por DMA mostraram um comportamento bastante distinto em função do óleo utilizado como solvente. O valor de Tg e o módulo de estocagem, G' correspondente à temperatura de "onset" variaram de 25 a 47ºC e 0,25 a 9 MPa, respectivamente. Os géis compostos com óleos parafínicos apresentaram os maiores valores de Tg e de G'. As análises de DSC revelaram um pico endotérmico que foi designado como sendo de dissolução, entre 75°C e 90°C e o correspondente pico exotérmico (60°C e 40°C verificado durante o resfriamento. Esse processo de dissolução foi atribuído aos processos de fusão e solvatação dos cristalitos de polietileno. As transições observadas por DMA estão relacionadas aos domínios de poliestireno do copolímero em bloco, em conjunto com as transições do polietileno e são muito afetadas pelo tipo de solvente. Os géis estudados apresentam dois mecanismos distintos de gelificação, via formação de cristalitos de polietileno e via formação de agregados de poliestireno dos blocos terminais do SEBS. O efeito dos óleos aromáticos e naftênicos sobre o módulo dos materiais foi relacionado com um aumento na interação entre os agregados de poliestireno e a fase etileno-butileno.Thermoreversible gels of styrene-ethylene/butylene-styrene block copolymers (SEBS and low density polyethylene dissolved in mineral paraffinic and polybutene oils, as well its mixtures, were prepared and characterized by differential scanning calorimetry (DSC and dynamic mechanical analysis (DMA. DMA analysis showed distinct behavior depending on the

  20. Development of Ultrafiltration Membrane-Separation Technology for Energy-Efficient Water Treatment and Desalination Process

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Woosoon [Univ. of Nevada, Las Vegas, NV (United States); Bae, Chulsung [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2016-10-28

    The growing scarcity of fresh water is a major political and economic challenge in the 21st century. Compared to thermal-based distillation technique of water production, pressure driven membrane-based water purification process, such as ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO), can offer more energy-efficient and environmentally friendly solution to clean water production. Potential applications also include removal of hazardous chemicals (i.e., arsenic, pesticides, organics) from water. Although those membrane-separation technologies have been used to produce drinking water from seawater (desalination) and non-traditional water (i.e., municipal wastewater and brackish groundwater) over the last decades, they still have problems in order to be applied in large-scale operations. Currently, a major huddle of membrane-based water purification technology for large-scale commercialization is membrane fouling and its resulting increases in pressure and energy cost of filtration process. Membrane cleaning methods, which can restore the membrane properties to some degree, usually cause irreversible damage to the membranes. Considering that electricity for creating of pressure constitutes a majority of cost (~50%) in membrane-based water purification process, the development of new nano-porous membranes that are more resistant to degradation and less subject to fouling is highly desired. Styrene-ethylene/butylene-styrene (SEBS) block copolymer is one of the best known block copolymers that induces well defined morphologies. Due to the polarity difference of aromatic styrene unit and saturated ethylene/butylene unit, these two polymer chains self-assemble each other and form different phase-separated morphologies depending on the ratios of two polymer chain lengths. Because the surface of SEBS is hydrophobic which easily causes fouling of membrane, incorporation of ionic group (e,g, sulfonate) to the polymer is necessary to reduces fouling

  1. Mechanochemistry with metallosupramolecular polymers.

    Science.gov (United States)

    Balkenende, Diederik W R; Coulibaly, Souleymane; Balog, Sandor; Simon, Yoan C; Fiore, Gina L; Weder, Christoph

    2014-07-23

    The transduction of mechanical force into useful chemical reactions is an emerging design approach to impart soft materials with new functions. Here, we report that mechanochemical transductions can be achieved in metallosupramolecular polymers. We show that both reversible and irreversible reactions are possible and useful to create mechanically responsive materials that display new functions. The metallopolymer studied was a cross-linked network assembled from a europium salt and a telechelic poly(ethylene-co-butylene) with 2,6-bis(1'-methylbenzimidazolyl)pyridine (Mebip) ligands at the termini. The Eu(3+) complexes serve both as mechanically responsive binding motifs and as built-in optical probes that can monitor the extent of (dis)assembly due to their characteristic photoluminescent properties. Indeed, dose-dependent and reversible metal-ligand dissociation occurs upon exposure to ultrasound in solution. The absence of ultrasound-induced dissociation of a low-molecular weight model complex and in-depth studies of temperature effects confirm that the dissociation is indeed the result of mechanical activation. The influence of the strength of the metal-ligand interactions on the mechanically induced dissociation was also explored. Metallopolymers in which the Mebip ligands were substituted with more strongly coordinating dipicolinate (dpa) ligands do not dissociate upon exposure to ultrasound. Finally, we show that mechanochemical transduction in metallosupramolecular polymers is also possible in the solid state. We demonstrate mending of damaged objects through ultrasound as well as mechanochromic behavior based on metal-exchange reactions in metallopolymers imbibed with an auxiliary metal salt.

  2. Stable phantom materials for ultrasound and optical imaging

    Science.gov (United States)

    Cabrelli, Luciana C.; Pelissari, Pedro I. B. G. B.; Deana, Alessandro M.; Carneiro, Antonio A. O.; Pavan, Theo Z.

    2017-01-01

    Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

  3. Conductive paint-filled cement paste sensor for accelerated percolation

    Science.gov (United States)

    Laflamme, Simon; Pinto, Irvin; Saleem, Hussam S.; Elkashef, Mohamed; Wang, Kejin; Cochran, Eric

    2015-04-01

    Cementitious-based strain sensors can be used as robust monitoring systems for civil engineering applications, such as road pavements and historic structures. To enable large-scale deployments, the fillers used in creating a conductive material must be inexpensive and easy to mix homogeneously. Carbon black (CB) particles constitute a promising filler due to their low cost and ease of dispersion. However, a relatively high quantity of these particles needs to be mixed with cement in order to reach the percolation threshold. Such level may influence the physical properties of the cementitious material itself, such as compressive and tensile strengths. In this paper, we investigate the possibility of utilizing a polymer to create conductive chains of CB more quickly than in a cementitious-only medium. This way, while the resulting material would have a higher conductivity, the percolation threshold would be reached with fewer CB particles. Building on the principle that the percolation threshold provides great sensing sensitivity, it would be possible to fabricate sensors using less conducting particles. We present results from a preliminary investigation comparing the utilization of a conductive paint fabricated from a poly-Styrene-co-Ethylene-co-Butylene-co-Styrene (SEBS) polymer matrix and CB, and CB-only as fillers to create cementitious sensors. Preliminary results show that the percolation threshold can be attained with significantly less CB using the SEBS+CB mix. Also, the study of the strain sensing properties indicates that the SEBS+CB sensor has a strain sensitivity comparable to the one of a CB-only cementitious sensor when comparing specimens fabricated at their respective percolation thresholds.

  4. Biodegradable polyesters based on succinic acid

    Directory of Open Access Journals (Sweden)

    Nikolić Marija S.

    2003-01-01

    Full Text Available Two series of aliphatic polyesters based on succinic acid were synthesized by copolymerization with adipic acid for the first series of saturated polyesters, and with fumaric acid for the second series. Polyesters were prepared starting from the corresponding dimethyl esters and 1,4-butanediol by melt transesterification in the presence of a highly effective catalyst tetra-n-butyl-titanate, Ti(0Bu4. The molecular structure and composition of the copolyesters was determined by 1H NMR spectroscopy. The effect of copolymer composition on the physical and thermal properties of these random polyesters were investigated using differential scanning calorimetry. The degree of crystallinity was determined by DSC and wide angle X-ray. The degrees of crystallinity of the saturated and unsaturated copolyesters were generally reduced with respect to poly(butylene succinate, PBS. The melting temperatures of the saturated polyesters were lower, while the melting temperatures of the unsaturated copolyesters were higher than the melting temperature of PBS. The biodegradability of the polyesters was investigated by enzymatic degradation tests. The enzymatic degradation tests were performed in a buffer solution with Candida cylindracea lipase and for the unsaturated polyesters with Rhizopus arrhizus lipase. The extent of biodegradation was quantified as the weight loss of polyester films. Also the surface of the polyester films after degradation was observed using optical microscopy. It could be concluded that the biodegradability depended strongly on the degree of crystallinity, but also on the flexibility of the chain backbone. The highest biodegradation was observed for copolyesters containing 50 mol.% of adipic acid units, and in the series of unsaturated polyesters for copolyesters containing 5 and 10 mol.% of fumarate units. Although the degree of crystallinity of the unsaturated polyesters decreased slightly with increasing unsaturation, the biodegradation

  5. Light-induced bonding and debonding with supramolecular adhesives.

    Science.gov (United States)

    Heinzmann, Christian; Coulibaly, Souleymane; Roulin, Anita; Fiore, Gina L; Weder, Christoph

    2014-04-09

    Light-responsive supramolecular polymers were applied as reversible adhesives that permit bonding and debonding on demand features. A telechelic poly(ethylene-co-butylene) (PEB) was functionalized with either self-complementary hydrogen-bonding ureidopyrimidinone (UPy) motifs (UPy-PEB-UPy) or 2,6-bis(1'-methylbenzimidazolyl)-pyridine (Mebip) ligands (Mebip-PEB-Mebip), which can coordinate to metal ions (Zn(NTf2)2) and form a metallosupramolecular polymer with the sum formula [Znx(Mebip-PEB-Mebip)](NTf2)2x, with x ≈ 1. In the latter case, light-heat conversion is facilitated by the ultraviolet (UV) light-absorbing metal-ligand motifs, while in the case of UPy-PEB-UPy a UV absorber was added for this purpose. Single lap joints were prepared by sandwiching films of the supramolecular polymers of a thickness of 80-100 μm between two glass, quartz, or stainless steel substrates and bonded by exposure to either UV light (320-390 nm, 900 mW/cm(2)) or heat (80 or 200 °C for UPy-PEB-UPy and the metallopolymer, respectively). UPy-PEB-UPy and [Zn0.8Mebip-PEB-Mebip](NTf2)1.6 displayed a shear strength of 0.9-1.2 and 1.8-2.5 MPa, respectively. When lap joints were placed under load and exposed to light or heat, the samples debonded within seconds. They could be rebonded through exposure to light or heat, and the original adhesive properties were recovered.

  6. Block copolymer micelles with pendant bifunctional chelator for platinum drugs: effect of spacer length on the viability of tumor cells.

    Science.gov (United States)

    Huynh, Vien T; Quek, Jing Yang; de Souza, Paul L; Stenzel, Martina H

    2012-04-09

    Three monomers with 1,3-dicarboxylate functional groups but varying spacer lengths were synthesized via carbon Michael addition using malonate esters and ethylene- (MAETC), butylene- (MABTC), and hexylene (MAHTC) glycol dimethacrylate, respectively. Poly[oligo-(ethylene glycol) methylether methacrylate] (POEGMEMA) was prepared in the presence of a RAFT (reversible addition-fragmentation chain transfer) agent, followed by chain extension with the prepared monomers to generate three different block copolymers (BP-E80, BP-B82, and BP-H79) with similar numbers of repeating units, but various spacer lengths as distinguishing features. Conjugation with platinum drugs created macromolecular platinum drugs resembling carboplatin. The amphiphilic natures of these Pt-containing block copolymers led to the formation micelles in solution. The rate of drug release of all micelles was similar, but a noticeable difference was the increasing stability of the micelle against dissociation with increasing spacer length. The platinum conjugated polymer showed high activity against A549, OVCAR3, and SKOV3 cancer cell lines exceeding the activity of carboplatin, but only the micelle based on the longest spacer had IC(50) values as low as cisplatin. Cellular uptake studies identified a better micelle uptake with increasing micelle stability as a possible reason for lower IC(50) values. The clonogenic assay revealed that micelles loaded with platinum drugs, in contrast to low molecular weight carboplatin, have not only better activity within the frame of a 72 h cell viability study, but also display a longer lasting effect by preventing the colony formation A549 for more than 10 days.

  7. Cyclization Phenomena in the Sol-Gel Polymerization of a,w-Bis(triethoxysilyl)alkanes and Incorporation of the Cyclic Structures into Network Silsesquioxane Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Alam, T.M.; Carpenter, J.P.; Dorhout, P.K.; Greaves, J.; Loy, D.A.; Shaltout, R.; Shea, K.J.; Small, J.H.

    1999-01-04

    Intramolecular cyclizations during acid-catalyzed, sol-gel polymerizations of ct,co- bis(tietioxysilyl)aWmes substintidly lengtien gelties formonomers witietiylene- (l), propylene- (2), and butylene-(3)-bridging groups. These cyclizations reactions were found, using mass spectrometry and %i NMR spectroscopy, to lead preferentially to monomeric and dimeric products based on six and seven membered disilsesquioxane rings. 1,2- Bis(triethoxysilyl)ethane (1) reacts under acidic conditions to give a bicyclic drier (5) that is composed of two annelated seven membered rings. Under the same conditions, 1,3- bis(triethoxysilyl)propane (2), 1,4-bis(triethoxysilyl)butane (3), and z-1,4- bis(triethoxysilyl)but-2-ene (10) undergo an intramolecular condensation reaction to give the six membemd and seven membered cyclic disilsesquioxanes 6, 7, and 11. Subsequently, these cyclic monomers slowly react to form the tricyclic dirners 8,9 and 12. With NaOH as polymerization catalyst these cyclic silsesquioxanes readily ~aeted to afford gels that were shown by CP MAS z%i NMR and infr=d spectroscopes to retain some cyclic structures. Comparison of the porosity and microstructwe of xerogels prepared from the cyclic monomers 6 and 7 with gels prepared directly from their acyclic precursors 2 and 3, indicate that the final pore structure of the xerogels is markedly dependent on the nature of the precursor. In addition, despite the fact that the monomeric cyclic disilsesquioxane species can not be isolated from 1-3 under basic conditions due to their rapid rate of gelation, spectroscopic techniques also detected the presence of the cyclic structures in the resulting polymeric gels.

  8. Acoustic and Elastic Properties of Glycerol in Oil-Based Gel Phantoms.

    Science.gov (United States)

    Cabrelli, Luciana C; Grillo, Felipe W; Sampaio, Diego R T; Carneiro, Antonio A O; Pavan, Theo Z

    2017-09-01

    Phantoms are important tools for image quality control and medical training. Many phantom materials have been proposed for ultrasound; most of them use water as the solvent, but these materials have disadvantages such as dehydration and low temporal stability if not properly stored. To overcome these difficulties, copolymer-in-oil gel was proposed as an inert and stable material; however, speed of sound for these materials is still lower than what is described for most biological tissues. Here, we propose the glycerol dispersion in oil-based gels to modify the acoustic and elastic properties of copolymer-in-oil phantoms. We manufactured copolymer-in-oil gels using styrene-ethylene/butylene-styrene (SEBS) in concentrations 8%-15%. We used 2 types of mineral oils with different viscosities. Glycerol was added in a volume fraction 0%-30% of the total amount of liquid. The acoustic (i.e., speed of sound, attenuation and backscattering) and the mechanical (i.e., density and Young's modulus) properties of the samples were within the range of values observed for soft tissues. The acoustic parameters of the samples were dependent on oil viscosity and glycerol concentration. The speed of sound ranged 1423 m/s - 1502 m/s, while the acoustic attenuation and the ultrasonic backscattering increased by adding glycerol. The density and the Young's moduli were less affected by the presence of glycerol. We conclude that glycerol can be used to control the acoustic parameters of copolymer-in-oil gels. Additionally, it opens the possibility of incorporating other oil-insoluble substances to control further properties of the phantom. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  9. Preparation and properties of polystyrene encapsulated paraffin wax as possible phase change material in a polypropylene matrix

    Energy Technology Data Exchange (ETDEWEB)

    Mochane, M.J. [Department of Chemistry, University of the Free State (Qwaqwa Campus), Phuthaditjhaba (South Africa); Luyt, A.S., E-mail: LuytAS@qwa.ufs.ac.za [Department of Chemistry, University of the Free State (Qwaqwa Campus), Phuthaditjhaba (South Africa)

    2012-09-20

    Highlights: Black-Right-Pointing-Pointer Polystyrene microcapsules containing about 30 wt% soft paraffin wax were successfully prepared. Black-Right-Pointing-Pointer The presence of microcapsules in polypropylene influenced the morphology and properties of the matrix. Black-Right-Pointing-Pointer The SEBS modifier had little influence on the interaction between polypropylene and microcapsules. - Abstract: The study deals with the preparation and characterization of polystyrene (PS) capsules containing Fischer-Tropsch paraffin wax (PS:wax) as phase change material (PCM) for thermal energy storage embedded in a polypropylene (PP) matrix. Blends of PP/PS:wax were prepared without and with polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) as a modifier. The influence of PS:wax microcapsules on the morphology, as well as thermal and mechanical properties of the PP was investigated. The scanning electron microscopy (SEM) images of the microencapsulated PCM show that the capsules were grouped in irregular spherical agglomerates of size 16-24 {mu}m. However, after melt-blending with PP smaller, perfectly spherical microcapsules were well dispersed in the PP matrix. There was fairly good interaction between the microcapsules and the matrix, even in the absence of SEBS modification. The FTIR spectrum of the microcapsules is almost exactly the same as that of polystyrene, which indicates that the microcapsules were mostly intact and that the FTIR only detected the polystyrene shell. The amount of wax in the PS:wax microcapsules was determined as 20-30% by weight. An increase in PS:wax content resulted in a decrease in the melting peak temperatures of PP. The thermal stability of the blends decreased with an increase in PS:wax microcapsules content as a consequence of the lower thermal stability of both the wax and PS. There was a drop in storage modulus with increasing PS:wax microcapsules content.

  10. Comparison of Extruder Systems for 3D Printer Filament Fabrication

    Science.gov (United States)

    Ramirez, Adriana

    Additive Manufacturing (AM) has grown in popularity over the past thirty years, due to its versatility, short design to product cycle, and capability to fabricate complex geometries, which cannot otherwise be produced. There exist several platforms that are able to print objects composed of different materials, making this technology significant in different fields such as: automotive, aerospace, medical, electronics, amongst others. Though several types of AM technologies are available, the expiration of the patents on fused deposition modeling (FDM) in 2009 has led to a widespread use of this platform in academia and home use settings. Widespread use of FDM-type AM platforms has led to a demand to fabricate feedstock materials for this AM platform. Particularly, in the home do it yourself (DIY) community there has been a widespread interest for users to manufacture their own feedstock filament leading to a large growth in home-use extrusion systems. The low cost of these desktop-grade systems has also made them attractive to academics, but there has not been a widespread effort into determining the efficacy of these small scale extrusion systems as compared to industrial quality extruders which are typically used to manufacture feedstock for FDM platforms. The aim of this study was to compare two extrusion processes: 1) a desktop grade single-screw extruder; and 2) an industrial scale twin-screw extruder. In order to understand differences between their performance and quality of mixing, a rubberized blend of acrylonitrile butadiene styrene (ABS) mixed with styrene ethylene butylene styrene with a maleic anhydride graft (SEBS-g-MA) at different ratios was compounded on each extrusion system. Melt flow index, and mechanical properties were compared. In addition, a raster pattern sensitivity study was performed to evaluate the effect of the extruder system on 3D printed objects. Finally, scanning electron microscopy (SEM) was used to examine the fracture surfaces

  11. Temperature-dependent absorption cross-section measurements of 1-butene (1-C4H8) in VUV and IR

    KAUST Repository

    Es-sebbar, Et-touhami

    2013-01-01

    Vacuum ultraviolet (VUV) and infrared (IR) absorption cross-section measurements of 1-butene (1-C4H8; CH2=CHCH2CH3; Butylene) are reported over the temperature range of 296-529K. The VUV measurements are performed between 115 and 205nm using synchrotron radiation as a tunable VUV light source. Fourier Transform Infrared (FTIR) spectroscopy is employed to measure absorption cross-section and band strengths in the IR region between 1.54 and 25μm (~6500-400cm-1). The measured room-temperature VUV and IR absorption cross-sections are compared with available literature data and are found to be in good agreement. The oscillator strength for the electronic transition (A1A\\'→X1A\\') around 150-205nm is determined to be 0.32±0.01.The gas temperature has a strong effect on both VUV and IR spectra. Measurements made in the VUV region show that the peak value of the band cross-section decreases and the background continuum increases with increasing gas temperature. This behavior is due to a change in the rotational and vibrational population distribution of 1-butene molecule. Similar changes in rotational population are observed in the IR spectra. Moreover, variation of the IR spectra with temperature is used to measure the enthalpy difference between syn and skew conformations of 1-butene and is found to be 0.24±0.03. kcal/mol, which is in excellent agreement with values reported in the literature. The measurements reported in this work will provide the much-needed spectroscopic information for the development of high-temperature quantitative diagnostics in combustion applications and validation of atmospheric chemistry models of extra-solar planets. © 2012 Elsevier Ltd.

  12. Proton exchange membranes based on PVDF/SEBS blends

    Science.gov (United States)

    Mokrini, A.; Huneault, M. A.

    Proton-conductive polymer membranes are used as an electrolyte in the so-called proton exchange membrane fuel cells. Current commercially available membranes are perfluorosulfonic acid polymers, a class of high-cost ionomers. This paper examines the potential of polymer blends, namely those of styrene-(ethylene-butylene)-styrene block copolymer (SEBS) and polyvinylidene fluoride (PVDF), in the proton exchange membrane application. SEBS/PVDF blends were prepared by twin-screw extrusion and the membranes were formed by calendering. SEBS is a phase-segregated material where the polystyrene blocks can be selectively functionalized offering high ionic conductivity, while PVDF insures good dimensional stability and chemical resistance to the films. Proton conductivity of the films was obtained by solid-state grafting of sulfonic acid moieties. The obtained membranes were characterized in terms of conductivity, ionic exchange capacity and water uptake. In addition, the membranes were characterized in terms of morphology, microstructure and thermo-mechanical properties to establish the blends morphology-property relationships. Modification of interfacial properties between SEBS and PVDF was found to be a key to optimize the blends performance. Addition of a methyl methacrylate-butyl acrylate-methyl methacrylate block copolymer (MMA-BA-MMA) was found to compatibilize the blend by reducing the segregation scale and improving the blend homogeneity. Mechanical resistance of the membranes was also improved through the addition of this compatibilizer. As little as 2 wt.% compatibilizer was sufficient for complete interfacial coverage and lead to improved mechanical properties. Compatibilized blend membranes also showed higher conductivities, 1.9 × 10 -2 to 5.5 × 10 -3 S cm -1, and improved water management.

  13. Stable phantom materials for ultrasound and optical imaging.

    Science.gov (United States)

    Cabrelli, Luciana C; Pelissari, Pedro I B G B; Deana, Alessandro M; Carneiro, Antonio A O; Pavan, Theo Z

    2017-01-21

    Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

  14. Preparation and characterization of composites based on PBAT/Starch blend, micro and nanofillers of bio-CaCO{sub 3}; Preparacao e caracterizacao de compositos baseados na blenda de PBAT/amido, micro e nanocargas de bio-CaCo{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Valquiria A.; Neto, Jose C. de M.; Moura, Esperidiana A.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil); Tiimob, Boniface; Rangari, Vijaya K. [Department of Materials Science and Engineering, Tuskegee University, Tuskegee, AL (United States); Silva, Raimundo N.A. da, E-mail: jmacedo@uea.edu.br [Universidade do Estado do Amazonas (UEA), Manaus, AM (Brazil). Escola Superior de Tecnologia. Coordenacao de Engenharia de Materiais

    2015-07-01

    Biodegradable polymeric materials have been used as an alternative to synthetic polymeric materials due to their reduced environmental impact. Among the biodegradable polymers is investigated poly (butylene adipate-co-terephthalate) (PBAT). This polymer has the flexibility, high strain at break and easy processing, but a high cost and low toughness that limits their applications. The development of PBAT blends with thermoplastic starch or other biodegradable polymers may lead to a balance of properties, expand its range of applications and also make it more economically viable. The mechanical properties of biodegradable PBAT blends may be further improved by incorporating micro or nanofillers from renewable sources. This study aimed to the processing and characterization of a PBAT/Starch blend reinforced with 2% (wt.) of bioCaCO{sub 3} nanoparticles (nano-bioCaCO{sub 3}) and 5% (wt.) of bioCaCO{sub 3}-micro (particles ≤ 125 μm). For the preparations were used a co-rotating twin-screw extruder. For the characterization of the prepared materials were used X-ray diffraction (XRD) and tensile test. The XRD results showed the greatest intensity peak of CaCO{sub 3} in the matrix for composites containing bio-CaCO{sub 3} nanofillers suggesting a better interaction between matrix and nanofillers. The results of the tensile test confirmed the better interaction between matrix and nanofillers. These results showed that the addition of only 2 % (wt.) of bio-CaCO{sub 3} nanoparticles in PBAT/Starch blend led to obtaining a tougher material with improved tensile strength and elastic modulus properties regarding the polymer blend. (author)

  15. Identification of dominant lactic acid bacteria isolated from grape juices. Assessment of its biochemical activities relevant to flavor development in wine

    Directory of Open Access Journals (Sweden)

    Fabiana Maria Saguir

    2009-06-01

    Full Text Available Fabiana Maria Saguir1,3, Iris Eleonora Loto Campos1, Carmen Maturano1, Maria Cristina Manca de Nadra1,2,31Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Tucumán, Argentina; 2Centro de Referencia para Lactobacilos (Cerela, Tucumán, Argentina; 3Career Investigators from Consejo Nacional de Investigaciones Científicas y Técnicas, ArgentinaAbstract: We investigated the dominant lactic acid bacteria (LAB from grape juice and commencement of malolactic fermentation (MLF samples of a cellar located in Argentina and assessment of its β-glucosidase activity and butter aroma compounds production. LAB number found in grape juice (approximately log10 3.3 was lower than that obtained in the MLF samples. Oenococcus oeni was predominant, accounting for 68% of the 81 LAB isolated. Majority of whole cells derived from O. oeni cultures at the end of the exponential growth showed detectable β-glucosidase activity. Contrarily, the highest proportion of them did not produce diacetyl, acetoin, and 2,3-butylene glycol. A direct relation between both properties among the O. oeni strains could not be established. In the selected MS25 strain, L-malic acid was compatible with good enzyme activity and was partially able to annul the negative influence of the low pH (3.8. In different conditions, the aroma compounds were lower than 4 mg/ml, especially at pH 3.8 and in presence of L-malic acid (2.5 g/l. This strain could have adequate characteristics for potential use in winemaking. Finally, the assessment of both biochemical properties in O. oeni should be considered as a quality criterion for selecting starter cultures for the improvement of the wines aroma.Keywords: isolation, lactic acid bacteria, biochemical properties, aroma, wine

  16. Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with l-ascorbic acid, as materials for soft tissue regeneration.

    Science.gov (United States)

    Kucinska-Lipka, J; Gubanska, I; Strankowski, M; Cieśliński, H; Filipowicz, N; Janik, H

    2017-06-01

    In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with l-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ( 1 HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test with

  17. Structure-property relationship in new photo-cured dimethacrylate-based dental resins.

    Science.gov (United States)

    Podgórski, Maciej

    2012-04-01

    In this study five novel dimethacrylates of different chain lengths having rigid aromatic rings were synthesized and proposed as possible dental monomers for dental resin mixtures. Four monomers were prepared by the reaction of glycidyl methacrylate with dicarboxylic acid esters obtained from phthalic anhydride and 1,3-propylene, 1,4-butylene, 1,5-penthylene and 1,6-hexylene glycols. The addition reaction of glycidyl methacrylate and the acidic compound was carried out in the presence of tetraethylammonium bromide. The fifth monomer was obtained from 1,5-penthylene glycol-based dimethacrylate by blocking its hydroxyl groups with acetyl groups. The monomers were photo-copolymerized with triethyleneglycol dimethacrylate (TEGDMA) in the presence of a photoinitiator which was 2,2-dimethoxy-2-phenyloacetophenone. Unfilled polymers were evaluated for photopolymerization conversion and volumetric curing shrinkage. Water sorption, water solubility, flexural strength and hardness were measured. The prepared polymers were also subjected to dynamic mechanical studies (DMA). Results show that, increasing the distance between double bonds decreases flexural modulus and hardness. As expected, the curing shrinkage increased with increasing degree of conversion. The acetylation of hydroxyl groups resulted in improved water uptake properties of the compositions. It was demonstrated that, depending upon the content of acetyl groups in the network, the glass transition temperature may be significantly lowered. In polymers with large amounts of pendant groups, β relaxation overlaps with α relaxation (glass transition temperature), and it is the former that discloses the maximum on the tanδ curve. The systematic change in the length of the new dimethacrylates provided insight into the effects on the resultant material properties. It was shown in the article that the properties of the new monomers compare favorably with properties of the commercially available resins. Copyright

  18. Development of an Arm Phantom for Testing Non-Invasive Blood Pressure Monitors

    Science.gov (United States)

    Anderson-Jackson, LaTecia D.

    Approximately one in every three adults age 20 older are diagnosed with high blood pressure or hypertension. It is estimated that hypertension affects 78 million people in the United States, is equally prevalent in both men and woman (Crabtree, Stuart-Shor, & McAllister, 2013). In the United States, around 78% of people suffering from hypertension are aware of their condition, with only 68% using hypertensive medications to control their blood pressure (Writing Group et al., 2010). Clinically, blood pressure measurements may lack accuracy, which can be attributed to various factors, including device limitations, cuff mis-sizing and misplacement, white-coat effect, masked hypertension, and lifestyle factors. The development of an arm phantom to simulate physiologic properties of a human arm and arterial BP waveforms may allow us to better assess the accuracy of non-invasive blood pressure (NIBP) monitors. The objective of this study are to: (1) Develop an arm phantom to replicate physiological properties of the human arm, and (2) Incorporate the arm phantom into a mock circulatory flow loop to simulate different physiological blood pressure readings on the bench. A tissue mimicking material, styrene-ethylene-butylene-styrene (SEBS), a co-block polymer was used to develop the arm phantom for in-vitro testing. To determine the optimal mechanical properties for the arm phantom, individual arm components were isolated and tested. A protocol was developed to evaluate various components for optimal arm phantom development. Mechanical testing was conducted on 10%, 15%, and 20% SEBS gel samples for modulus of elasticity measurements in order to simulate physiological properties of the human arm. As a result of the SEBS polymer being a new material for this application, this investigation will contribute to resolving the limitations that occurred during experimentation. In this study, we demonstrated that although SEBS polymer may be an ideal material to use for simulating

  19. Enhancement of the optical properties of a new radiochromic dosimeter based on aliphatic-aromatic biodegradable polymers

    Energy Technology Data Exchange (ETDEWEB)

    Schimitberger, Thiago, E-mail: tschimitberger@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Departamento de Engenharia Nuclear; Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    The development of a dosimeter that is of low cost, easy to process without dependence on expensive complex instruments and environment friendly is a challenging in irradiation quality control. Recently, an aliphatic-aromatic biodegradable polymer has been proposed as radiochromic dosimeter. The dosimeter is based on biodegradable poly(butylene adipate-co-terephthalate) copolymers (PBAT). In order to improve the photoluminescence (PL) properties of PBAT, increasing its range of applicability (50 kGy to 1000 kGy), this work investigates the influence of solution concentration in the dose response. Films with thickness of c.a. 80 μm were produce by wirebar coating, a simple deposition method for preparing large areas of organic films at low cost. The irradiation of samples was performed at room temperature using a Co-60 source at dose rate of 20 kGy/h. The films were exposed to doses ranging from 501 kGy to 1000 kGy. A 405 nm LED light source was used to excite the films. The USB2000 spectrometer made by Ocean Optics was used to collect the emission spectra of the luminescent films. The photoluminescent intensity captured by the spectrometer present linear radiation dose dependence. The maximum PL for the film sample made from a 0.05 g.mL{sup -1} solution is 1.5 (a.u.) while it is about 3.5 (a.u.) for a film sample made from a 0.2 mg.mL{sup -1} solution, when irradiated with 1000 kGy. These results indicate that PBAT films have great potential to be used as a high gamma dose radiochromic dosimeter over a wide dose range, expanding its applicability for different radiations process. (author)

  20. Rinse-resistant superhydrophobic block copolymer fabrics by electrospinning, electrospraying and thermally-induced self-assembly

    Science.gov (United States)

    Wu, Jie; Li, Xin; Wu, Yang; Liao, Guoxing; Johnston, Priscilla; Topham, Paul D.; Wang, Linge

    2017-11-01

    An inherent problem that restricts the practical application of superhydrophobic materials is that the superhydrophobic property is not sustainable; it can be diminished, or even lost, when the surface is physically damaged. In this work, we present an efficient approach for the fabrication of superhydrophobic fibrous fabrics with great rinse-resistance where a block copolymer has been electrospun into a nanofibrous mesh while micro-sized beads have been subsequently electrosprayed to give a morphologically composite material. The intricate nano- and microstructure of the composite was then fixed by thermally annealing the block copolymer to induce self-assembly and interdigitation of the microphase separated domains. To demonstrate this approach, a polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) nanofibrous scaffold was produced by electrospinning before SEBS beads were electrosprayed into this mesh to form a hierarchical micro/nanostructure of beads and fibers. The effects of type and density of SEBS beads on the surface morphology and wetting properties of composite membranes were studied extensively. Compared with a neat SEBS fibrous mesh, the composite membrane had enhanced hydrophobic properties. The static water contact angle increased from 139° (±3°) to 156° (±1°), while the sliding angle decreased to 8° (±1°) from nearly 90°. In order to increase the rinse-resistance of the composite membrane, a thermal annealing step was applied to physically bind the fibers and beads. Importantly, after 200 h of water flushing, the hierarchical surface structure and superhydrophobicity of the composite membrane were well retained. This work provides a new route for the creation of superhydrophobic fabrics with potential in self-cleaning applications.

  1. Double Crystalline Multiblock Copolymers with Controlling Microstructure for High Shape Memory Fixity and Recovery.

    Science.gov (United States)

    Huang, Miaoming; Zheng, Liuchun; Wang, Lili; Dong, Xia; Gao, Xia; Li, Chuncheng; Wang, Dujin

    2017-09-06

    The shape memory performance of double crystalline poly(butylene succinate)-co-poly(ε-caprolactone) (PBS-co-PCL) multiblock copolymers with controlling microstructure was studied, and the corresponding microstructure origin was further quantitatively analyzed by wide and small-angle X-ray scattering (WAXS and SAXS) experiments. It was found that the multiblock copolymer with higher PCL content, proper deformation strain, and inhibited crystallization of PBS (lower crystallinity and smaller crystal size, which could be realized by quenching from the melt) would exhibit better shape memory fixity and recovery performance. WAXS and SAXS results revealed that the shape fixity ratio (Rf) was closely related with the relative crystallinity of the PCL component, while the shape recovery ratio (Rr) strongly relied on the deformation and recovery behavior of the PBS and PCL components that changed along with compositions and deformation strains. For the copolymer with higher PCL content (BS30CL70), at the lower deformation strain (0% ∼ 90%), both the PBS and PCL components after recovery had no orientation (labeled as stage I), resulting in almost complete recovery; with the deformation strain increasing (90% ∼ 200%), it was the irreversible deformation of the PCL component that largely took responsibility for the decreased Rr (stage II). On the contrary, when the PCL content decreased to 50 wt % (BS50CL50), stage I (0% ∼ 50%) and stage II (50% ∼ 100%) appeared in much lower strains; with the deformation strain increasing (100% ∼ 200%), the irreversible deformation of both PBS and PCL components was mainly responsible for the further reduction of Rr (stage III). It could exhibit excellent shape memory performance for biodegradable double crystalline multiblock copolymers by controlling the composition, deformation strain, and crystallization, which might have wide application prospects in biomedical areas.

  2. Acceleration of percolation for cementitious sensors using conductive paint filler

    Science.gov (United States)

    Pinto, Irvin Jude Joseph

    Structural health monitoring has emerged as an important branch of civil engineering in recent times, with the need to automatically monitor structural performance over time to ensure structural integrity. More recently, the advent of smart sensing materials has given this field a major boost. Research has shown that smart sensing materials fabricated with conductive filler at a concentration close to the percolation threshold results in high sensitivity to strain due to the piezoresistive effect. Of particular interest to this research are cementitious sensors fabricated using carbon black fillers. Carbon black is considered because of its widespread availability and low cost over other conductive fillers such as carbon nanotubes and carbon nanofibers. A challenge in the fabrication of these sensors is that cementitious materials require a significant amount of carbon black to percolate, resulting in a loss in mechanical properties. This research investigates a new method to accelerate percolation of the materials, enabling cementitious sensors with fewer carbon black particles. A carbon black-based conductive paint that allows earlier percolation by facilitating conducting networks in cementitious sensors is used. The conductive paint consists of a block copolymer, SEBS (styrene-co-ethylene-co-butylene-co-styrene), filled with carbon black particles. The percolation thresholds of sensors fabricated both with and without conductive paint are, as well as their strain sensing characteristics and compressive strength. The study found that SEBS could successfully reduce the percolation threshold by 42%, and that samples with SEBS showed better electrical responses in dynamic conditions. Despite showing lower compressive strength, cementitious sensors fabricated with this novel conductive paint show promise for real time health monitoring applications.

  3. Polypropylene/Short Glass Fibers Composites: Effects of Coupling Agents on Mechanical Properties, Thermal Behaviors, and Morphology

    Directory of Open Access Journals (Sweden)

    Jia-Horng Lin

    2015-12-01

    Full Text Available This study uses the melt compounding method to produce polypropylene (PP/short glass fibers (SGF composites. PP serves as matrix while SGF serves as reinforcement. Two coupling agents, maleic anhydride grafted polypropylene, (PP-g-MA and maleic anhydride grafted styrene-ethylene-butylene-styrene block copolymer (SEBS-g-MA are incorporated in the PP/SGF composites during the compounding process, in order to improve the interfacial adhesion and create diverse desired properties of the composites. According to the mechanical property evaluations, increasing PP-g-MA as a coupling agent provides the composites with higher tensile, flexural, and impact properties. In contrast, increasing SEBS-g-MA as a coupling agent provides the composites with decreasing tensile and flexural strengths, but also increasing impact strength. The DSC results indicate that using either PP-g-MA or SEBS-g-MA as the coupling agent increases the crystallization temperature. However, the melting temperature of PP barely changes. The spherulitic morphology results show that PP has a smaller spherulite size when it is processed with PP-g-MA or SEBS-g-MA as the coupling agent. The SEM results indicate that SGF is evenly distributed in PP matrices, but there are distinct voids between these two materials, indicating a poor interfacial adhesion. After PP-g-MA or SEBS-g-MA is incorporated, SGF can be encapsulated by PP, and the voids between them are fewer and indistinctive. This indicates that the coupling agents can effectively improve the interfacial compatibility between PP and SGF, and as a result improves the diverse properties of PP/SGF composites.

  4. Nanoengineered Eggshell-Silver Tailored Copolyester Polymer Blend Film with Antimicrobial Properties.

    Science.gov (United States)

    Tiimob, Boniface J; Mwinyelle, Gregory; Abdela, Woubit; Samuel, Temesgen; Jeelani, Shaik; Rangari, Vijaya K

    2017-03-08

    In this study, the reinforcement effect of different proportions of eggshell/silver (ES-Ag) nanomaterial on the structural and antimicrobial properties of 70/30 poly(butylene-co-adipate terephthalate)/polylactic acid (PBAT/PLA) immiscible blends was investigated. The ES-Ag was synthesized using a single step ball milling process and characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). These results confirmed the existence of silver nanoparticles (Ag NPs) in the interstitial spaces of the eggshell particles. The thin films in this study were prepared using hot melt extrusion and 3D printing for mechanical and antimicrobial testing, respectively. These films were also characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), XRD, tensile testing, and antimicrobial analysis. It was found that the incorporation of ES-Ag (0.5-2.0% content) compromised the tensile properties of the blend, due to poor interaction between the matrix and the ES-Ag in the ternary systems, but thermal analysis revealed improvement in the onset of degradation temperature and char yield at 500 °C. Though film toughness was better than that of PLA, the strength was lower, yet synergistic to those of PBAT and PLA. In general, the PBAT/PLA/ES-Ag ternary system had properties intermediate to those of the pure polymers. In vitro assessment of the antimicrobial activity of these films conducted on Listeria monocytogenes and Salmonella Enteritidis bacteria revealed that the blend composite films possessed bacteriostatic effects, due to the immobilized ES-Ag nanomaterials in the blend matrix. Atomic absorption spectroscopy (AAS) analysis of water and food samples exposed to the films showed that Ag NPs were not released in distilled water and chicken breast after 72 and 168 h, respectively.

  5. Functional analysis of FarA transcription factor in the regulation of the genes encoding lipolytic enzymes and hydrophobic surface binding protein for the degradation of biodegradable plastics in Aspergillus oryzae.

    Science.gov (United States)

    Garrido, Sharon Marie; Kitamoto, Noriyuki; Watanabe, Akira; Shintani, Takahiro; Gomi, Katsuya

    2012-05-01

    FarA is a Zn(II)(2)Cys(6) transcription factor which upregulates genes required for growth on fatty acids in filamentous fungi like Aspergillus nidulans. FarA is also highly similar to the cutinase transcription factor CTF1α of Fusarium solani which binds to the cutinase gene promoter in this plant pathogen. This study determines whether FarA transcriptional factor also works in the regulation of genes responsible for the production of cutinase for the degradation of a biodegradable plastic, poly-(butylene succinate-co-adipate) (PBSA), in Aspergillus oryzae. The wild-type and the farA gene disruption strains were grown in minimal agar medium with emulsified PBSA, and the wild-type showed clear zone around the colonies while the disruptants did not. Western blot analysis revealed that the cutinase protein CutL1 and a hydrophobic surface binding protein such as HsbA were produced by the wild-type but not by the disruptants. In addition, the expressions of cutL1, triacylglycerol lipase (tglA), and mono- and di-acylglycerol lipase (mdlB) genes as well as the hsbA gene were significantly lower in the disruptants compared to the wild-type. These results indicated that the FarA transcriptional factor would be implicated in the expression of cutL1 and hsbA genes that are required for the degradation of PBSA as well as lipolytic genes such as mdlB and tglA for lipid hydrolysis. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  6. Short-term organic carbon migration from polymeric materials in contact with chlorinated drinking water.

    Science.gov (United States)

    Mao, Guannan; Wang, Yingying; Hammes, Frederik

    2018-02-01

    Polymeric materials are widely used in drinking water distribution systems. These materials could release organic carbon that supports bacterial growth. To date, the available migration assays for polymeric materials have not included the potential influence of chlorination on organic carbon migration behavior. Hence, we established a migration and growth potential protocol specifically for analysis of carbon migration from materials in contact with chlorinated drinking water. Four different materials were tested, including ethylene propylene dienemethylene (EPDM), poly-ethylene (PEX b and PEX c) and poly-butylene (PB). Chlorine consumption rates decreased gradually over time for EPDM, PEXc and PB. In contrast, no free chlorine was detected for PEXb at any time during the 7 migration cycles. Total organic carbon (TOC) and assimilable organic carbon (AOC) was evaluated in both chlorinated and non-chlorinated migrations. TOC concentrations for EPDM and PEXb in chlorinated migrations were significantly higher than non-chlorinated migrations. The AOC results showed pronounced differences among tested materials. AOC concentrations from chlorinated migration waters of EPDM and PB were higher compared to non-chlorinated migrations, whereas the opposite trend was observed for PEXb and PEXc. There was also a considerable difference between tested materials with regards to bacterial growth potential. The results revealed that the materials exposed to chlorine-influenced migration still exhibited a strong biofilm formation potential. The overall results suggested that the choice in material would make a considerable difference in chlorine consumption and carbon migration behavior in drinking water distribution systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Transesterification Reactions in PC/PBT Blend in Presence of Nanoclay Particles and Their Effect on Blend Morphology

    Directory of Open Access Journals (Sweden)

    Razieh Mehrabi Kooshki

    2013-06-01

    Full Text Available Recently, using nanoparticles in polymeric blend have been considered by many researchers a new epoch for generation of materials to meet different requirements in various industries such as car, sport, military, structure and electronic. The transesterification reaction in polyester blends during melt mixing plays an important role in the components compatibility, and the ultimate properties of the blend affected by this reaction. In this study the transesterification reaction in the blend of poly(butylene terephthalate (PBT/polycarbonate (PC was studied at the presence of three commercial organic modified montmorillonite namely Cloisite 30B, Cloisite 20A and Cloisite 15A. The main difference among these nanoparticles is their surface chemical structures and initial gallery heights. Fourier transform infrared spectroscopy (FTIR and small angel X-ray scattering (SAXS analysis showed that tranesterification reaction was improved at the presence of Cloisite 20A and Cloisite 15A and an intercalation morphology was obtained. While in the samples containing Cloisite 30B a thermal degradation occurred and initial gallery of the nanoparticles was increased. Dynamical mechanical thermal analysis results revealed that by addition of nanoclay to polymer blend, the glass transition of polymers draw on to each other which means more compatibility has been obtained and transestrification reaction has been improved at presence of the nanoparticles. Scanning electron microscope (SEM micrographs showed droplet-matrix morphology for PC/PBT: 70/30 ratio and co-continuous for PC/PBT: 50/50. By incorporation of nanoparticles the finer morphology was obtained in PC/PBT: 70/30 and co- continuous morphology changed to micro co-continuous in PC/PBT: 50/50.

  8. Three-dimensional assembly of tissue-engineered cartilage constructs results in cartilaginous tissue formation without retainment of zonal characteristics.

    Science.gov (United States)

    Schuurman, W; Harimulyo, E B; Gawlitta, D; Woodfield, T B F; Dhert, W J A; van Weeren, P R; Malda, J

    2016-04-01

    Articular cartilage has limited regenerative capabilities. Chondrocytes from different layers of cartilage have specific properties, and regenerative approaches using zonal chondrocytes may yield better replication of the architecture of native cartilage than when using a single cell population. To obtain high seeding efficiency while still mimicking zonal architecture, cell pellets of expanded deep zone and superficial zone equine chondrocytes were seeded and cultured in two layers on poly(ethylene glycol)-terephthalate-poly(butylene terephthalate) (PEGT-PBT) scaffolds. Scaffolds seeded with cell pellets consisting of a 1:1 mixture of both cell sources served as controls. Parallel to this, pellets of superficial or deep zone chondrocytes, and combinations of the two cell populations, were cultured without the scaffold. Pellet cultures of zonal chondrocytes in scaffolds resulted in a high seeding efficiency and abundant cartilaginous tissue formation, containing collagen type II and glycosaminoglycans (GAGs) in all groups, irrespective of the donor (n = 3), zonal population or stratified scaffold-seeding approach used. However, whereas total GAG production was similar, the constructs retained significantly more GAG compared to pellet cultures, in which a high percentage of the produced GAGs were secreted into the culture medium. Immunohistochemistry for zonal markers did not show any differences between the conditions. We conclude that spatially defined pellet culture in 3D scaffolds is associated with high seeding efficiency and supports cartilaginous tissue formation, but did not result in the maintenance or restoration of the original zonal phenotype. The use of pellet-assembled constructs leads to a better retainment of newly produced GAGs than the use of pellet cultures alone. Copyright © 2013 John Wiley & Sons, Ltd.

  9. Coalescence in PLA-PBAT blends under shear flow: Effects of blend preparation and PLA molecular weight

    Energy Technology Data Exchange (ETDEWEB)

    Nofar, M. [Center for High Performance Polymer and Composite Systems (CREPEC), Chemical Engineering Department, Polytechnique Montreal, Montreal, Quebec H3T 1J4, Canada and CREPEC, Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2 (Canada); Heuzey, M. C.; Carreau, P. J., E-mail: pierre.carreau@polymtl.ca [Center for High Performance Polymer and Composite Systems (CREPEC), Chemical Engineering Department, Polytechnique Montreal, Montreal, Quebec H3T 1J4 (Canada); Kamal, M. R. [CREPEC, Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2 (Canada); Randall, J. [NatureWorks LLC, 15305 Minnetonka Boulevard, Minnetonka, Minnesota 55345 (United States)

    2016-07-15

    Blends containing 75 wt. % of an amorphous polylactide (PLA) with two different molecular weights and 25 wt. % of a poly[(butylene adipate)-co-terephthalate] (PBAT) were prepared using either a Brabender batch mixer or a twin-screw extruder. These compounds were selected because blending PLA with PBAT can overcome various drawbacks of PLA such as its brittleness and processability limitations. In this study, we investigated the effects of varying the molecular weight of the PLA matrix and of two different mixing processes on the blend morphology and, further, on droplet coalescence during shearing. The rheological properties of these blends were investigated and the interfacial properties were analyzed using the Palierne emulsion model. Droplet coalescence was investigated by applying shear flows of 0.05 and 0.20 s{sup −1} at a fixed strain of 60. Subsequently, small amplitude oscillatory shear tests were conducted to investigate changes in the viscoelastic properties. The morphology of the blends was also examined using scanning electron microscope (SEM) micrographs. It was observed that the PBAT droplets were much smaller when twin-screw extrusion was used for the blend preparation. Shearing at 0.05 s{sup −1} induced significant droplet coalescence in all blends, but coalescence and changes in the viscoelastic properties were much more pronounced for the PLA-PBAT blend based on a lower molecular weight PLA. The viscoelastic responses were also somehow affected by the thermal degradation of the PLA matrix during the experiments.

  10. Design of porous scaffolds for cartilage tissue engineering using a three-dimensional fiber-deposition technique.

    Science.gov (United States)

    Woodfield, T B F; Malda, J; de Wijn, J; Péters, F; Riesle, J; van Blitterswijk, C A

    2004-08-01

    In this study, we present and characterize a fiber deposition technique for producing three-dimensional poly(ethylene glycol)-terephthalate-poly(butylene terephthalate) (PEGT/PBT) block co-polymer scaffolds with a 100% interconnecting pore network for engineering of articular cartilage. The technique allowed us to "design-in" desired scaffold characteristics layer by layer by accurately controlling the deposition of molten co-polymer fibers from a pressure-driven syringe onto a computer controlled x-y-z table. By varying PEGT/PBT composition, porosity and pore geometry, 3D-deposited scaffolds were produced with a range of mechanical properties. The equilibrium modulus and dynamic stiffness ranged between 0.05-2.5 and 0.16-4.33 MPa, respectively, and were similar to native articular cartilage explants (0.27 and 4.10 MPa, respectively). 3D-deposited scaffolds seeded with bovine articular chondrocytes supported a homogeneous cell distribution and subsequent cartilage-like tissue formation following in vitro culture as well as subcutaneous implantation in nude mice. This was demonstrated by the presence of articular cartilage extra cellular matrix constituents (glycosaminoglycan and type II collagen) throughout the interconnected pore volume. Similar results were achieved with respect to the attachment of expanded human articular chondrocytes, resulting in a homogeneous distribution of viable cells after 5 days dynamic seeding. The processing methods and model scaffolds developed in this study provide a useful method to further investigate the effects of scaffold composition and pore architecture on articular cartilage tissue formation.

  11. Surface energy and stiffness discrete gradients in additive manufactured scaffolds for osteochondral regeneration.

    Science.gov (United States)

    Di Luca, Andrea; Longoni, Alessia; Criscenti, Giuseppe; Lorenzo-Moldero, Ivan; Klein-Gunnewiek, Michel; Vancso, Julius; van Blitterswijk, Clemens; Mota, Carlos; Moroni, Lorenzo

    2016-02-27

    Swift progress in biofabrication technologies has enabled unprecedented advances in the application of developmental biology design criteria in three-dimensional scaffolds for regenerative medicine. Considering that tissues and organs in the human body develop following specific physico-chemical gradients, in this study, we hypothesized that additive manufacturing (AM) technologies would significantly aid in the construction of 3D scaffolds encompassing such gradients. Specifically, we considered surface energy and stiffness gradients and analyzed their effect on adult bone marrow derived mesenchymal stem cell differentiation into skeletal lineages. Discrete step-wise macroscopic gradients were obtained by sequentially depositing different biodegradable biomaterials in the AM process, namely poly(lactic acid) (PLA), polycaprolactone (PCL), and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymers. At the bulk level, PEOT/PBT homogeneous scaffolds supported a higher alkaline phosphatase (ALP) activity compared to PCL, PLA, and gradient scaffolds, respectively. All homogeneous biomaterial scaffolds supported also a significantly higher amount of glycosaminoglycans (GAGs) production compared to discrete gradient scaffolds. Interestingly, the analysis of the different material compartments revealed a specific contribution of PCL, PLA, and PEOT/PBT to surface energy gradients. Whereas PEOT/PBT regions were associated to significantly higher ALP activity, PLA regions correlated with significantly higher GAG production. These results show that cell activity could be influenced by the specific spatial distribution of different biomaterial chemistries in a 3D scaffold and that engineering surface energy discrete gradients could be considered as an appealing criterion to design scaffolds for osteochondral regeneration.

  12. Efeito da adição de diferentes copolímeros em blendas HDPE/HIPS pós-consumo: morfologia de fases e propriedades térmicas The effect of different block copolymers on post consumer HDPE/HIPS Blends: phase morphology and thermal properties

    Directory of Open Access Journals (Sweden)

    Igor S. B. Perez

    2008-09-01

    Full Text Available Blendas de poliolefinas/HIPS têm sido exploradas para obter filmes especiais com determinadas propriedades desejadas, tornando imperativo desenvolver vários estudos para um melhor conhecimento do comportamento desses materiais. Neste trabalho, efeitos da adição dos copolímeros comerciais de estireno-butadieno multibloco (SBS e de estireno-(etileno-co-butileno-estireno (SEBS tribloco linear em blendas pós-consumo de HDPE e HIPS são reportados. A diminuição nas dimensões da microfase dispersa, aliada à rugosidade superficial da fase HDPE após extração seletiva do HIPS, independentemente de a fase matriz ser HIPS ou HDPE, mostraram mais eficiência do SEBS como modificador interfacial de tensão ou como surfactante entre os diferentes domínios quando comparado com o SBS. Os resultados das caracterizações térmicas, por exemplo, menor Tm e menor grau de cristalinidade do HDPE, e maior Tg do poliestireno na presença de SEBS corroboraram esta conclusão, como será discutido posteriormente.Blending of post-consumer polyolefins/HIPS has been exploited for obtaining special films with a desired set of properties, which has required studies to understand the behavior of these materials. In this work the effects of commercial multiblock styrene-butadiene (SBS and linear triblock styrene-(ethylene-co-butylene-styrene (SEBS copolymers in blends of post-consumer high density polyethylene (HDPE and HIPS are reported. Thermal properties and phase morphology were comparatively analyzed for the additives aiming at verifying possible correlations between them. Decreased dimensions of the minor micro phase along with HDPE surface roughness after HIPS selective extraction, independently of the matrix being HIPS or HDPE, showed better effectiveness for SEBS as interfacial tension modifier or as surfactant at the different domains interface when compared with SBS. The results of thermal characterizations, e.g. lower HDPE melting temperature, lower

  13. Effect of anti-inflamentation extracts from Korean traditional medicinal herb

    Directory of Open Access Journals (Sweden)

    Zhang Xiaowan

    2014-09-01

    Full Text Available Five Mix Plant Extracts according to different extraction solvents were assessed for its cell viability and anti-inflammatory activity by in vitro methods. The single plant extract was extracted with 70% ethanol(EtOH and the mix plants(C.kousa, R.multiflora, T.nucifera, M.basjoo and S.glabra were extracted with EtOH 30%, 70%; Butylene Glycol(BG 30%, 70%; Propylene Glycol(PG 30%, 70%; Distilled Water(D.W. Cell viability was measured using the Micro culture tetrazolium (MTT assay method and Human fibroblast cells, CCD 1102 KERTr were used. The plant extracts with the maximum concentration that none toxic to the cells were evaluated for anti-inflammatory activity. Anti-inflammatory activity was evaluated using lipoxygenase inhibition assay method. A dose response curve was plotted to determine the IC50 values. Results showed that, at the 5 kinds of single plant extracts by 70% EtOH extraction solvent, it showed the IC50 was 280ug/ml of S1, 370ug/ml of S2, 380ug/ml of S3, 170ug/ml of S4 and 190ug/ml of S5. At the mix plant extracts by 7 kinds of extraction solvents (70%, 30% EtOH; 70%, 30% BG; 70%, 30% PG; D.W, it showed the IC50 was 140ug/ml of M E70, 140ug/ml of M E30, 120ug/ml of M BG70, 110ug/ml of M BG30, 120ug/ml of M PG70, 136ug/ml of M PG30 and 120ug/ml of M D.W. From the results, it is concluded that when these five plants mixed before extraction, it will extract more active ingredients with anti-inflammatory effects. Further study we will analyzing plants effective single compound using high performance liquid chromatography (HPLC profiling and progressing the experiments in vivo.

  14. VOCs emission rate estimate for complicated industrial area source using an inverse-dispersion calculation method: A case study on a petroleum refinery in Northern China.

    Science.gov (United States)

    Wei, Wei; Lv, Zhaofeng; Yang, Gan; Cheng, Shuiyuan; Li, Yue; Wang, Litao

    2016-11-01

    This study aimed to apply an inverse-dispersion calculation method (IDM) to estimate the emission rate of volatile organic compounds (VOCs) for the complicated industrial area sources, through a case study on a petroleum refinery in Northern China. The IDM was composed of on-site monitoring of ambient VOCs concentrations and meteorological parameters around the source, calculation of the relationship coefficient γ between the source's emission rate and the ambient VOCs concentration by the ISC3 model, and estimation of the actual VOCs emission rate from the source. Targeting the studied refinery, 10 tests and 8 tests were respectively conducted in March and in June of 2014. The monitoring showed large differences in VOCs concentrations between background and downwind receptors, reaching 59.7 ppbv in March and 248.6 ppbv in June, on average. The VOCs increases at receptors mainly consisted of ethane (3.1%-22.6%), propane (3.8%-11.3%), isobutane (8.5%-10.2%), n-butane (9.9%-13.2%), isopentane (6.1%-12.9%), n-pentane (5.1%-9.7%), propylene (6.1-11.1%) and 1-butylene (1.6%-5.4%). The chemical composition of the VOCs increases in this field monitoring was similar to that of VOCs emissions from China's refineries reported, which revealed that the ambient VOCs increases were predominantly contributed by this refinery. So, we used the ISC3 model to create the relationship coefficient γ for each receptor of each test. In result, the monthly VOCs emissions from this refinery were calculated to be 183.5 ± 89.0 ton in March and 538.3 ± 281.0 ton in June. The estimate in June was greatly higher than in March, chiefly because the higher environmental temperature in summer produced more VOCs emissions from evaporation and fugitive process of the refinery. Finally, the VOCs emission factors (g VOCs/kg crude oil refined) of 0.73 ± 0.34 (in March) and 2.15 ± 1.12 (in June) were deduced for this refinery, being in the same order with previous direct

  15. Fabrication of zeolitic imidazolate framework-8-methacrylate monolith composite capillary columns for fast gas chromatographic separation of small molecules.

    Science.gov (United States)

    Yusuf, Kareem; Badjah-Hadj-Ahmed, Ahmed Yacine; Aqel, Ahmad; ALOthman, Zeid Abdullah

    2015-08-07

    A composite zeolitic imidazolate framework-8 (ZIF-8) with a butyl methacrylate-co-ethylene dimethacrylate (BuMA-co-EDMA) monolithic capillary column (33.5cm long×250μm i.d.) was fabricated to enhance the separation efficiency of methacrylate monoliths toward small molecules using conventional low-pressure gas chromatography in comparison with a neat butyl methacrylate-co-ethylene dimethacrylate (BuMA-co-EDMA) monolithic capillary column (33.5cm long×250μm i.d.). The addition of 10mgmL(-1) ZIF-8 micro-particles increased the BET surface area of BuMA-co-EDMA by 3.4-fold. A fast separation of five linear alkanes in 36s with high resolution (Rs≥1.3) was performed using temperature program. Isothermal separation of the same sample also showed a high efficiency (3315platesm(-1) for octane) at 0.89min. Moreover, the column was able to separate skeletal isomers, such as iso-octane/octane and 2-methyl octane/nonane. In addition, an iso-butane/iso-butylene gas mixture was separated at ambient temperature. Comparison with an open tubular TR-5MS column (30m long×250μm i.d.) revealed the superiority of the composite column in separating the five-membered linear alkane mixture with 4-5 times increase in efficiency and a total separation time of 0.89min instead of 4.67min. A paint thinner sample was fully separated using the composite column in 2.43min with a good resolution (Rs≥0.89). The perfect combination between the polymeric monolith, with its high permeability, and ZIF-8, with its high surface area and flexible 0.34nm pore openings, led to the fast separation of small molecules with high efficiency and opened a new horizon in GC applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Propriedades mecânicas e morfologia de uma blenda polimérica de PP/HIPS compatibilizada com SEBS Mechanical properties and morphology of a PP/HIPS polymer blend compatibilized with SEBS

    Directory of Open Access Journals (Sweden)

    Tomás J. A. de Mélo

    2000-06-01

    Full Text Available Neste trabalho o efeito da adição de 2 a 7% em peso de um copolímero tribloco estireno-b-etileno-co-butileno-b-estireno (SEBS em uma blenda polipropileno/poliestireno de alto impacto (PP/HIPS 70:30 foi determinado. As propriedades em tração e impacto, temperatura de amolecimento Vicat e morfologia da blenda PP/HIPS (70:30 em função da concentração de SEBS foram determinadas. As blendas foram processadas em extrusora dupla-rosca contra-rotativa interpenetrante e as amostras moldadas por compressão. Os resultados mostraram que, embora a adição do SEBS tenha promovido um aumento muito leve na resistência tênsil e no módulo elástico, observou-se um expressivo aumento no alongamento na ruptura e na resistência ao impacto das blendas; a temperatura Vicat das blendas foi superior à do HIPS e que a adição do SEBS promoveu uma redução significativa do tamanho de partícula, indicando que o SEBS exerceu um efeito emulsificante e estabilizador na morfologia das blendas investigadas. Resultados otimizados foram obtidos para a composição contendo 5% de SEBS, o que foi atribuido à uma maior compatibilidade entre as fases.In this work the effect of a 2-7% w/w styrene-b-ethylene-co-butylene-b-styrene triblock copolymer (SEBS addition on the properties of a 70:30 polypropylene/high impact polystyrene (PP/HIPS polymer blend was investigated. Tensile and impact properties, the Vicat temperature and blend morphology were determined as a function of SEBS content. Processing was carried out in a twin-screw intermeshing counter-rotating extruder and the samples were compression moulded. Our results indicate that the SEBS addition, albeit promoting very slight increases on tensile strenght and modulus, led to increases on the elongation at break and impact strenght of the blends, and the Vicat temperature of the blends was higher than that of HIPS. The SEM analysis showed that SEBS addition promotes a significant reduction on particle size

  17. Processing and characterization of solid and microcellular biobased and biodegradable PHBV-based polymer blends and composites

    Science.gov (United States)

    Javadi, Alireza

    Petroleum-based polymers have made a significant contribution to human society due to their extraordinary adaptability and processability. However, due to the wide-spread application of plastics over the past few decades, there are growing concerns over depleting fossil resources and the undesirable environmental impact of plastics. Most of the petroleum-based plastics are non-biodegradable and thus will be disposed in landfills. Inappropriate disposal of plastics may also become a potential threat to the environment. Many approaches, such as efficient plastics waste management and replacing petroleum-based plastics with biodegradable materials obtained from renewable resources, have been put forth to overcome these problems. Plastics waste management is at its beginning stages of development which is also more expensive than expected. Thus, there is a growing interest in developing sustainable biobased and biodegradable materials produced from renewable resources such as plants and crops, which can offer comparable performance with additional advantages, such as biodegradability, biocompatibility, and reducing the carbon footprint. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is one of the most promising biobased and biodegradable polymers, In fact many petroleum based polymers such as poly(propylene) (PP) can be potentially replaced by PHBV because of the similarity in their properties. Despite PHBV's attractive properties, there are many drawbacks such as high cost, brittleness, and thermal instability, which hamper the widespread usage of this specific polymer. The goals of this study are to investigate various strategies to address these drawbacks, including blending with other biodegradable polymers such as poly (butylene adipate-coterephthalate) (PBAT) or fillers (e.g., coir fiber, recycled wood fiber, and nanofillers) and use of novel processing technologies such as microcellular injection molding technique. Microcellular injection molding technique

  18. Engineering of Mixed Matrix Membranes for Water Treatment, Protective Coating and Gas Separation

    KAUST Repository

    Hammami, Mohamed Amen

    2017-11-01

    Mixed Matrix Membranes (MMMs) have received worldwide attention during the last decades. This is due to the fact that the resulting materials can combine the good processability and low cost of polymer membranes with the diverse functionality, high performance and thermal properties of the fillers. This work explores the fabrication and application of MMMs. We focused on the design and fabrication of nanofillers to impart target functionality to the membrane for water treatment, protective coating and gas separation. This thesis is divided into three sections according to the application including: I- Water Treatment: This part is divided into three chapters, two related to the membrane distillation (MD) and one related to the oil spill. Three different nanofillers have been used: Periodic mesoporous organosilica (PMO), graphene and carbon nanotube (CNT). Those nanofillers were homogeneously incorporated into polyetherimide (PEI) electrospun nanofiber membranes. The doped nanoparticle not only improved the mechanical properties and thermal stability of the pristine fiber but also enhanced the MD and oil spill performance due to the functionality of those nanofillers. II- Protective coating: This part includes two chapters describing the design and the fabrication of a smart antibacterial and anti-corrosion coating. In the first project, we fabricated colloidal lysozyme-templated gold nanoclusters gating antimicrobial-loaded silica nanoparticles (MSN-AuNCs@lys) as nano-fillers in poly(ethylene oxide)/poly(butylene terephthalate) polymer matrix. MSN-AuNCs@lys dispersed homogeneously within the polymer matrix with zero NPs leaching. The system was coated on a common radiographic dental imaging device that is prone to oral bacteria contamination. This coating can successfully sense and inhibit bacterial contamination via a controlled release mechanism that is only triggered by bacteria. In the second project, the coaxial electrospinning approach has been applied to

  19. New results of studying of the Devonian shale formation in the Volga-Ural region

    Science.gov (United States)

    Plotnikova, Irina; Pronin, Nikita; Morozov, Vladimir; Nosova, Fidania

    2015-04-01

    matter). Organic matter is characteristic mainly of the most siliceous formations. In "pure" carbonates, which are represented by micro-layers with different capacities, OM is not observed at all or its content is quite low. We found a connection between the type of organic matter and the composition of adsorbed gas. The study of adsorbed gases show the following: all samples have increased, high and abnormally high concentration of selected gases. Their common characteristic is that the gases are heavy, fatty, and have low methane content and hydrocarbons of unsaturated series (ethylene, propylene and butylene). Heavy hydrocarbons of saturated series are dominating, their share is changing irregularly in the homologous series. The use of aromatic carotenoids and alkyl toluenes can restore paleo facies conditions of sedimentation of the Domanik strata and paleo geodynamics of the part passive continental margin of the Baltica Late-Proterozoic continent.

  20. Geochemical Features of Shale Hydrocarbons of the Central Part of Volga-Ural Oil and Gas Province

    Science.gov (United States)

    Nosova, Fidania F.; Pronin, Nikita V.; Plotnikova, Irina N.; Nosova, Julia G.

    2014-05-01

    heterogeneity in the composition of organic matter, which varies from sapropel to sapropel - humus. The study of adsorbed gases show the following: all samples have increased, high and abnormally high concentration of selected gases. Their common characteristic is that the gases are heavy, fatty, and have low methane content and hydrocarbons of unsaturated series (ethylene, propylene and butylene). Heavy hydrocarbons of saturated series are dominating, their share is changing irregularly in the homologous series . There is a relation between silica and organic matter content, the amount of organic matter and adsorbed gas, the presence of lube fraction and isotopic composition.

  1. Comportamento mecânico e termo-mecânico de blendas poliméricas PBT/ABS Mechanical and thermo-mechanical behavior of PBT/ABS polymer blends

    Directory of Open Access Journals (Sweden)

    Luís Antonio S. Ferreira

    1997-03-01

    Full Text Available RESUMO: Blendas de poli(tereftalato de butileno (PBT e copolímero ABS foram estudadas usando-se três tipos diferentes de ABS. As blendas foram caracterizadas mecanicamente através de ensaios de tração e de impacto, e termo-mecanicamente através da determinação da temperatura de deflexão térmica (HDT. Uma influência mais pronunciada foi observada para a variação da composição química do ABS, em relação às diferentes composições de fase, onde blendas com ABS de maior proporção de acrilonitrila mostraram melhor comportamento. Foi observado que baixos níveis de ABS nas blendas proporcionam principalmente um aumento pronunciado da HDT e sem variação da resistência ao impacto, em relação ao PBT puro. Por outro lado, baixos níveis de PBT nas blendas não alteram as propriedades em relação ao ABS puro, com exceção da resistência ao impacto, que mostrou uma redução significativa.ABSTRACT: Polymer blends of poly(butylene terephthalate, PBT, and three grades of Acrylonitrile-Butadiene-Styrene copolymer, ABS, were studied. Polymer blends were characterized by impact resistance, tensile strength and heat deflection temperature tests. It was observed a stronger influence of the chemical composition of the ABS resin on the blends properties, mainly for the blends with higher ABS content which show better properties, than the phase composition of the ABS. It was observed that low levels of ABS in the blends promote mainly a high increase in HDT at the same level of impact resistance, as compared to neat PBT. On the other hand, low levels of PBT in the blend basically keep all the properties at the same level except the impact resistance which shows a significant decrease.

  2. Studies in reactive extrusion processing of biodegradable polymeric materials

    Science.gov (United States)

    Balakrishnan, Sunder

    Various reaction chemistries such as Polymerization, Polymer cross-linking and Reactive grafting were investigated in twin-screw extruders. Poly (1,4-dioxan-2-one) (PPDX) was manufactured in melt by the continuous polymerization of 1,4-dioxan-2-one (PDX) monomer in a twin-screw extruder using Aluminum tri-sec butoxide (ATSB) initiator. Good and accurate control over molecular weight was obtained by controlling the ratio of monomer to initiator. A screw configuration consisting of only conveying elements was used for the polymerization. The polymerization reaction was characterized by a monomer-polymer dynamic equilibrium, above the melting temperature of the polymer, limiting the equilibrium conversion to 78-percent. Near complete (˜100-percent) conversion was obtained on co-polymerizing PDX monomer with a few mol-percent (around 8-percent) Caprolactone (CL) monomer in a twin-screw extruder using ATSB initiator. The co-polymers exhibited improved thermal stability with reduction in glass transition temperature. The extruder was modeled as an Axial Dispersed Plug Flow Reactor for the polymerization of CL monomer using Residence Time Distribution (RTD) Analysis. The model provided a good fit to the experimental RTD and conversion data. Aliphatic and aliphatic-aromatic co-polyesters, namely Polycaprolactone (PCL) and Poly butylenes (adipate-co-terephthalate) (Ecoflex) were cross-linked in a twin-screw extruder using radical initiator to form micro-gel reinforced biodegradable polyesters. Cross-linked Ecoflex was further extrusion blended with talc to form blends suitable to be blown into films. A screw configuration consisting of conveying and kneading elements was found to be effective in dispersion of the talc particles (5--10 microns) in the polyester matrix. While the rates of crystallization increased for the talc filled polyester blends, overall crystallinity reduced. Mechanical, tear and puncture properties of films made using the talc filled polyester blends

  3. Water-enhanced solvation of organics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jane H. [Univ. of California, Berkeley, CA (United States)

    1993-07-01

    Water-enhanced solvation (WES) was explored for Lewis acid solutes in Lewis base organic solvents, to develop cheap extract regeneration processes. WES for solid solutes was determined from ratios of solubilities of solutes in water-sat. and low-water solvent; both were determined from solid-liquid equilibrium. Vapor-headspace analysis was used to determine solute activity coefficients as function of organic phase water concentration. WES magnitudes of volatile solutes were normalized, set equal to slope of log γs vs xw/xs curve. From graph shape Δ(log γs) represents relative change in solute activity coefficient. Solutes investigated by vapor-headspace analysis were acetic acid, propionic acid, ethanol, 1,2-propylene glycol, 2,3-butylene glycol. Monocarboxylic acids had largest decrease in activity coefficient with water addition followed by glycols and alcohols. Propionic acid in cyclohexanone showed greatest water-enhancement Δ(log γacid)/Δ(xw/xacid) = -0.25. In methylcyclohexanone, the decrease of the activity coefficient of propionic acid was -0.19. Activity coefficient of propionic acid in methylcyclohexanone stopped decreasing once the water reached a 2:1 water to acid mole ratio, implying a stoichiometric relation between water, ketone, and acid. Except for 2,3-butanediol, activity coefficients of the solutes studied decreased monotonically with water content. Activity coefficient curves of ethanol, 1,2-propanediol and 2,3-butanediol did not level off at large water/solute mole ratio. Solutes investigated by solid-liquid equilibrium were citric acid, gallic acid, phenol, xylenols, 2-naphthol. Saturation concentration of citric acid in anhydrous butyl acetate increased from 0.0009 to 0.087 mol/L after 1.3 % (g/g) water co-dissolved into organic phase. Effect of water-enhanced solvation for citric acid is very large but very small for phenol and its derivatives.

  4. Chelating agents for uranium(VI): 2. Efficacy and toxicity of tetradentate catecholate and hydroxypyridinonate ligands in mice.

    Science.gov (United States)

    Durbin, P W; Kullgren, B; Ebbe, S N; Xu, J; Raymond, K N

    2000-05-01

    Uranium(VI) (UO2(2+), uranyl) is nephrotoxic. Depending on isotopic composition and dosage, U(VI) is also chemically toxic and carcinogenic in bone. Several ligands containing two, three, or four bidentate catecholate or hydroxypyridinonate metal binding groups, developed for in vivo chelation of other actinides, were found, on evaluation in mice, to be effective for in vivo chelation of U(VI). The most promising ligands contained two bidentate groups per chelator molecule (tetradentate) attached to linear 4- or 5-carbon backbones (4-LI, butylene; 5-LI, pentylene; 5-LIO, diethyl ether). New ligands were then prepared to optimize ligand affinity for U(VI) in vivo and low acute toxicity. Five bidentate binding groups--sulfocatechol [CAM(S)], carboxycatechol [CAM(C)], methylterephthalamide (MeTAM), 1,2-hydroxypyridinone (1,2-HOPO), or 3,2-hydroxypyridinone (Me-3,2-HOPO)--were each attached to two linear backbones (4-LI and 5-LI or 5-LIO). Those ten tetradentate ligands and octadentate 3,4,3-LI(1,2-HOPO), an effective actinide chelator, were evaluated in mice for in vivo chelation of 233U(VI) (injection at 3 min, 1 h, or 24 h or oral administration at 3 min after intravenous injection of 233UO2Cl2) and for acute toxicity (100 micromol kg(-1) injected daily for 10 d). The combined efficacy and toxicity screening identified 5-LIO(Me-3,2-HOPO) and 5-LICAM(S) as the most effective low-toxicity agents. They chelate circulating U(VI) efficiently at ligand:uranium molar ratios > or = 20, remove useful amounts of newly deposited U(VI) from kidney and bone at molar ratios > or = 100, and reduce kidney U(VI) levels significantly when given orally at molar ratios > or = 100. 5-LIO(Me-3,2-HOPO) has greater affinity for kidney U(VI) while 5-LICAM(S) has greater affinity for bone U(VI), and a 1:1 mixture (total molar ratio = 91) reduced kidney and bone U(VI) to 15 and 58% of control, respectively--more than an equimolar amount of either ligand alone.

  5. Defeating anisotropy in material extrusion 3D printing via materials development

    Science.gov (United States)

    Torrado Perez, Angel Ramon

    ABS, UHMWPE (Ultra High Molecular Weight Polyethylene) and SEBS (Styrene Ethylene Butylene Styrene) were further examined due to the potential they demonstrated as low anisotropic materials in terms of strength. Also, the geometrical influence of different standard tensile specimens was studied. The development of materials that lead to lowered anisotropy on the strength of 3D printed parts has been successfully demonstrated, and alternative methodologies for the evaluation of anisotropic characteristics has been proposed as well. The present work shows the beginning to a better understanding of the mechanics taking place during the fusion of deposited material in MEAM.

  6. Design of supported bi-metallic nanoparticles based on Platinum and Palladium using Surface Organometallic Chemistry (SOMC)

    KAUST Repository

    Al-Shareef, Reem A.

    2017-11-01

    Well-defined silica supported bimetallic catalysts Pt100-x Pdx (where x is the molar ratio of Pd) are prepared by Surface Organometallic Chemistry (SOMC) via controlled decomposition of Pd2(allyl)2Cl2 on Pt/SiO2. For comparison purposes, Pt100-x Pdx bimetallic catalysts is also prepared by ion-exchange (IE). According to the results of STEM, XAS and H2 chemisorption, all bimetallic nanoparticles, prepared using neither SOMC nor IE, produce discrete formation of monometallic species (either Pt or Pd). Most catalysts exhibit a narrow particle size distribution with an average diameter ranging from 1 to 3 nm for samples prepared by IE and from 2 to 5 nm for the ones synthesized by SOMC. For all catalysts investigated in the present work, iso-butane reaction with hydrogen under differential conditions (conversions below 5%) leads to the formation of methane and propane (hydrogenolysis), n-butane (isomerization), and traces of iso-butylene (dehydrogenation). The total rate of reaction decreases with increasing the Pd loading for both catalysts series as a result of decreasing turnover rate (expressed as moles converted per total surface metal per second) of both isomerization and hydrogenolysis. In the case of Pt100-x Pdx(SOMC) catalysts, the results suggest a selective coverage of Pt (100) surface by a Pd layer, followed by a buildup of Pd overcoat onto a Pd layer assuming that each metal keeps its intrinsic catalytic properties. There is no mutual electronic charge transfer between the two metals (DFT). For the PtPd catalysts prepared by IE, the catalytic behavior cannot simply be explained by a surface coverage of highly active Pt metal by less active Pd (not observed), suggesting there is formation of a surface alloy between Pt and Pd collaborated by EXAFS and DFT. The catalytic results are explained by a simple structure activity relationship based on the previously proposed mechanism of C-H bond and C-C Bond activation and cleavage for iso-butane hydrogenolysis

  7. Final report on the safety assessment of Arnica montana extract and Arnica montana.

    Science.gov (United States)

    2001-01-01

    Arnica Montana Extract is an extract of dried flowerheads of the plant, Arnica montana. Arnica Montana is a generic term used to describe a plant material derived from the dried flowers, roots, or rhizomes of A. montana. Common names for A. montana include leopard's bane, mountain tobacco, mountain snuff, and wolf's bane. Two techniques for preparing Arnica Montana Extract are hydroalcoholic maceration and gentle disintegration in soybean oil. Propylene glycol and butylene glycol extractions were also reported. The composition of these extracts can include fatty acids, especially palmitic, linoleic, myristic, and linolenic acids, essential oil, triterpenic alcohols, sesquiterpene lactones, sugars, phytosterols, phenol acids, tannins, choline, inulin, phulin, arnicin, flavonoids, carotenoids, coumarins, and heavy metals. The components present in these extracts are dependent on where the plant is grown. Arnica Montana Extract was reported to be used in almost 100 cosmetic formulations across a wide range of product types, whereas Arnica Montana was reported only once. Extractions of Arnica Montana were tested and found not toxic in acute toxicity tests in rabbits, mice, and rats; they were not irritating, sensitizing, or phototoxic to mouse or guinea pig skin; and they did not produce significant ocular irritation. In an Ames test, an extract of A. montana was mutagenic, possibly related to the flavenoid content of the extract. No carcinogenicity or reproductive/developmental toxicity data were available. Clinical tests of extractions failed to elicit irritation or sensitization, yet Arnica dermatitis, a delayed type IV allergy, is reported in individuals who handle arnica flowers and may be caused by sesquiterpene lactones found in the flowers. Ingestion of A. montana-containing products has induced severe gastroenteritis, nervousness, accelerated heart rate, muscular weakness, and death. Absent any basis for concluding that data on one member of a botanical

  8. Final report on the safety assessment of Calendula officinalis extract and Calendula officinalis.

    Science.gov (United States)

    2001-01-01

    Calendula Officinalis Extract is an extract of the flowers of Calendula officinalis, the common marigold, whereas Calendula Officinalis is described as plant material derived from the flowers of C. officinalis. Techniques for preparing Calendula Officinalis Extract include gentle disintegration in soybean oil. Propylene glycol and butylene glycol extractions were also reported. Components of these ingredients are variously reported to include sugars, carotenoids, phenolic acids, sterols, saponins, flavonoids, resins, sterins, quinones, mucilages, vitamins, polyprenylquinones, and essential oils. Calendula Officinalis Extract is reported to be used in almost 200 cosmetic formulations, over a wide range of product categories. There are no reported uses of Calendula Officinalis. Acute toxicity studies in rats and mice indicate that the extract is relatively nontoxic. Animal tests showed at most minimal skin irritation, and no sensitization or phototoxicity. Minimal ocular irritation was seen with one formulation and no irritation with others. Six saponins isolated from C. officinalis flowers were not mutagenic in an Ames test, and a tea derived from C. officinalis was not genotoxic in Drosophila melanogaster. No carcinogenicity or reproductive and developmental toxicity data were available. Clinical testing of cosmetic formulations containing the extract elicited little irritation or sensitization. Absent any basis for concluding that data on one member of a botanical ingredient group can be extrapolated to another in a group, or to the same ingredient extracted differently, these data were not considered sufficient to assess the safety of these ingredients. Additional data needs include current concentration of use data; function in cosmetics; ultraviolet (UV) absorption data; if absorption occurs in the UVA or UVB range, photosensitization data are needed; gross pathology and histopathology in skin and other major organ systems associated with repeated dermal

  9. Adjustment of surface chemical and physical properties with functionalized polymers to control cell adhesion

    Science.gov (United States)

    Zhou, Zhaoli

    Cell-surface interaction is crucial in many cellular functions such as movement, growth, differentiation, proliferation and survival. In the present work, we have developed several strategies to design and prepare synthetic polymeric materials with selected cues to control cell attachment. To promote neuronal cell adhesion on the surfaces, biocompatible, non-adhesive PEG-based materials were modified with neurotransmitter acetylcholine functionalities to produce hydrogels with a range of porous structures, swollen states, and mechanical strengths. Mice hippocampal cells cultured on the hydrogels showed differences in number, length of processes and exhibited different survival rates, thereby highlighting the importance of chemical composition and structure in biomaterials. Similar strategies were used to prepare polymer brushes to assess how topographical cues influence neuronal cell behaviors. The brushes were prepared using the "grown from" method through surface-initiated atom transfer radical polymerization (SI-ATRP) reactions and further patterned via UV photolithography. Protein absorption tests and hippocampal neuronal cell culture of the brush patterns showed that both protein and neuronal cells can adhere to the patterns and therefore can be guided by the patterns at certain length scales. We also prepared functional polymers to discourage attachment of undesirable cells on the surfaces. For example, we synthesized PEG-perfluorinated alkyl amphiphilic surfactants to modify polystyrene-block-poly(ethylene-ran-butylene)- block-polyisoprene (SEBI or K3) triblock copolymers for marine antifouling/fouling release surface coatings. Initial results showed that the polymer coated surfaces can facilitate removal of Ulva sporelings on the surfaces. In addition, we prepared both bioactive and dual functional biopassive/bioactive antimicrobial coatings based on SEBI polymers. Incubating the polymer coated surfaces with gram-positive bacteria (S. aureus), gram

  10. Chemical and enzymatic catalytic routes to polyesters and oligopeptides biobased materials

    Science.gov (United States)

    Zhu, Jianhui

    My Ph.D research focuses on the synthesis and property studies of different biobased materials, including polyesters, polyurethanes and oligopeptides. The first study describes the synthesis, crystal structure and physico-mechanical properties of a bio-based polyester prepared from 2,5-furandicarboxylic acid (FDCA) and 1,4-butanediol. Melt-polycondensation experiments were conducted by a two-stage polymerization using titanium tetraisopropoxide (Ti[OiPr] 4) as catalyst. Polymerization conditions (catalyst concentration, reaction time and 2nd stage reaction temperature) were varied to optimize poly(butylene furan dicarboxylate), PBF, molecular weight. A series of PBFs with different Mw were characterized by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), X-Ray diffraction and tensile testing. Influence of molecular weight and melting/crystallization enthalpy on PBF material tensile properties was explored. Cold-drawing tensile tests at room temperature for PBF with Mw 16K to 27K showed a brittle-to-ductile transition. When Mw reaches 38K, the Young's Modulus of PBF remains above 900 MPa, and the elongation at break increases to above 1000%. The mechanical properties, thermal properties and crystal structures of PBF were similar to petroleum derived poly(butylenes terephthalate), PBT. Fiber diagrams of uniaxially stretched PBF films were collected, indexed, and the unit cell was determined as triclinic (a=4.78(3) A, b=6.03(5) A, c=12.3(1) A, alpha=110.1(2)°, beta=121.1(3)°, gamma=100.6(2)°). A crystal structure was derived from this data and final atomic coordinates are reported. We concluded that there is a close similarity of the PBF structure to PBT alpha- and beta-forms. In the second study, a biobased long chain polyester polyol (PC14-OH) was synthesized from o-hydroxytetradecanoic acid (o-HOC14) and 1,4-butanediol. The first section about polyester polyurethanes describes the synthesis

  11. Design of biobased and biodegradable - compostable engineered plastics based on poly(lactide)

    Science.gov (United States)

    Schneider, Jeffrey Samuelson

    Poly(lactide) (PLA) is a biobased and biodegradable - compostable plastic that is derived from renewable resources such as corn and sugar cane. It possesses excellent strength and stiffness properties and is recognized as safe for biomedical and food packaging applications. Commercially, it costs $1/lb and is now competitive with petroleum based polymers that have dominated the industry for decades. However, the material has some inherently weak properties that prevent it from certain applications - most notably, its rheological properties, brittleness, and poor high temperature performance. Cost effective modifications of the polymer to enhance these deficiencies could allow for increased applications and further its commercial growth. Multiple synthetic strategies have been developed to address PLA's performance property deficiencies. PLA typically exhibits poor melt strength and does not have the ability to strain harden, partially a result of its highly linear nature. Strain hardening and high melt strength are crucial elements of a material when producing blown films, a large untapped market for PLA. By increasing molecular weight and introducing long-chain branching into the material, these properties can be improved. Epoxy-functionalized PLA (EF-PLA) was synthesized by reacting PLA with a multifunctional epoxy polymer (MEP) using reactive extrusion processing (REX). These modified PLA polymers can function as a rheology modifier for PLA and a compatibilizer for blends with other biopolyesters. The modified PLA showed an increased melt strength and exhibited significant strain hardening, thus making it more suited for blown film applications. Blown films comprised of PLA and poly(butylene adipate-co-terephthalate) (PBAT) were produced using EF-PLA as a reactive modifier for rheological enhancement and compatibilization. This resulted in films with better processability (as seen by increased bubble stability) and improved mechanical properties, compared to a

  12. Viabilidade celular de nanofibras de polímeros biodegradáveis e seus nanocompósitos com argila montmorilonita Cell viability of nanofibers from biodegradable polymers and their nanocomposites with montmorillonite

    Directory of Open Access Journals (Sweden)

    Alfredo M. Goes

    2012-01-01

    Full Text Available Mantas não tecidas de nanofibras de três polímeros biodegradáveis poli(ácido láctico, PDLLA, poli(Ε-caprolactona, PCL, e poli(butileno adipato-co-tereftalato, PBAT e seus nanocompósitos com uma nanoargila montmorilonita (MMT foram produzidas por eletrofiação. A morfologia, o comportamento térmico e a estrutura interna das nanofibras foram analisados por microscopia eletrônica de varredura e transmissão, calorimetria diferencial de varredura e difração de raios X, respectivamente. Observou-se que as nanofibras dos nanocompósitos possuíam diâmetros menores do que os correspondentes polímeros puros e que as nanofibras de PBAT puro e de PBAT/MMT apresentavam a menor cristalinidade de todas as mantas. A viabilidade celular de todas as nanofibras foi analisada pela técnica de redução do sal de tetrazolium pelo complexo enzimático piruvato desidrogenase presente na matriz de mitocôndrias (teste MTT. Os resultados mostraram que nenhuma manta nanofibrílica apresentou toxicidade às células e que as nanofibras de PBAT puro e seu nanocompósito propiciaram ainda um ambiente mais favorável ao desenvolvimento celular de fibroblastos de cardiomiócitos do que as condições oferecidas pelo controles, provavelmente por apresentarem menores diâmetros e baixa cristalinidade em relação às demais nanofibras. Estes resultados mostram o potencial de uso destas mantas nanofibrílicas como suportes de crescimento celular.Non-woven mats of nanofibers of three biodegradable polymers, viz. poly(lactic acid, PDLLA, poly(Ε-caprolactone, PCL, and poly(butylene adipate-co-terephthalate, PBAT, and their nanocomposites with montmorillonite nanoclay (MMT were produced by electrospinning. The morphology, thermal behavior and internal structure of the nanofibers were analyzed by scanning and transmission electron microscopy, differential scanning calorimetry and wide angle X-ray diffraction, respectively. The nanofibers of the nanocomposites had

  13. Final report on the safety assessment of Hypericum perforatum extract and Hypericum perforatum oil.

    Science.gov (United States)

    2001-01-01

    Hypericum Perforatum Extract is an extract of the capsules, flowers, leaves, and stem heads of Hypericum perforatum, commonly called St. John's Wort. Hypericum Perforatum Oil is the fixed oil from H. perforatum. Techniques for preparing Hypericum Perforatum Extract include crushing in stabilized olive oil, gentle maceration over a period of weeks, followed by dehydration and filtration. Propylene Glycol and Butylene Glycol extractions were also reported. The following components have variously been reported to be found in H. perforatum: hypericin, naphtodianthrones, flavonoids, terpene and sesquiterpene oils, phenylpropanes, biflavones, tannins, xanthones, phloroglucinols, and essential oils. Hypericum Perforatum Extract is used in over 50 cosmetic formulations and Hypericum Perforatum Oil in just over 10, both across a wide range of product types. Acute toxicity studies using rats, guinea pigs, and mice indicate that the extract is relatively nontoxic. Animals fed H. perforatum flowers for 2 weeks showed significant signs of toxicity, including erythema, edema of the portion of the body exposed to light, alopecia, and changes in blood chemistry. In a chronic study, rats fed H. perforatum gained less weight than control animals. Mixtures containing the extract and the oil were not irritants or sensitizers in animals. Because of the presence of hypericin, H. perforatum is a primary photosensitizer. In clinical tests, a single oral administration of Hypericum extract resulted in hypericin appearing in the blood. With long-term dosing, a steady-state level in blood was reached after 14 days. The polyphenol fraction of H. perforatum had immunostimulating activity, whereas the lipophilic portion had immunosuppressing properties. Mixtures of the extract and the oil produced minimal or no ocular irritation in rabbit eyes. Mutagenic activity in an Ames test was attributed to flavonols in one study and to quercitin in another, but other genotoxicity assays were negative. No

  14. Phenolic resin-based porous carbons for adsorption and energy storage applications

    Science.gov (United States)

    Wickramaratne, Nilantha P.

    view. So far, carbons with high surface area and nitrogen content have been vastly studied. Also, there are several reports showing the importance of pore size towards CO2 adsorption at ambient conditions. In the case of nitrogen containing carbons, it was shown that the incorporation of nitrogen into carbon matrix is a challenging task. In chapter 3, we discussed how to improve the surface area and pore size distribution of phenolic resin-based carbons to obtain optimum CO 2 adsorption capacities at ambient conditions. The chemical and physical activation of polymer/carbon particles is used to generate necessary physical properties of the final carbons, which display unprecedented CO2 adsorption capacities at ambient conditions. Moreover, the modified Stober-like methods are used for the synthesis of nitrogen containing carbon particles. These facile synthesis methods afford highly porous nitrogen containing carbons with comparatively high CO2 adsorption capacities at ambient conditions. Chapter 4 begins with synthesis of ultra large mesoporous carbons using (ethylene oxide)38 (butylene oxide)46 (ethylene oxide) 38 triblock copolymer as a soft template and phenolic resins as the carbon precursors. Even though, there are many reports dealing with the synthesis of mesoporous silica with large pores for bio-molucular adsorption their high cost discourage them to use in industrial applications. However, cheap mesoporous carbons with large pores (>15 nm) are potential materials for bio-molecular adsorption on large scale. The first part of chapter 4 is demonstrates the synthesis of mesoporous carbons with ultra large pores for bio-molecular adsorption. Lysozyme was selected as a model biomolecule for adsorption processes. The second part of Chapter 4 is focused on functionalized polymer spheres for heavy metal ions adsorption. It is shown that the synthesis of functionalized polymer spheres can be achieved by using modified Stober method; the reacting spheres show very

  15. Electroactive behavior of nanostructured polymers

    Science.gov (United States)

    Shankar, Ravi

    Electroactive polymers (EAPs) offer a new class of actuator materials, which display physical response to electrical excitation. EAPs can be classified into two groups based on their response mechanism: electronic EAPs and ionic EAPs. Electronic EAPs respond due to electrostatic or Coulomb forces developed on application of an electric field, whereas ionic EAPs are driven by mobility or diffusion of ions. Electronic EAPs display better properties than ionic EAPs in terms of their high actuation strain, reliability and durability, efficiency, and response time. Dielectric electroactive polymers or D-EAPs produce large actuation strain on application of an electric field due to Maxwell stress effect. D-EAPs have superior performance than other EAPs, which is ascribed to their high actuation strain, fast response time, high energy density, and high efficiency. Acrylic elastomer is known to be superior amongst electric EAPs due to its highest areal actuation strain (˜160 %), highest elastic energy density (3.4 MJ/m3), and highest pressure (7 MPa). Generally, all the D-EAPs require very high electric field for actuation. In this work, we demonstrate that incorporation of a low-volatility, aliphatic-rich solvent (mineral oil) into a nanostructured poly [styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) triblock copolymer yields physically cross-linked micellar networks, known as thermoplastic elastomer gels (TPEG). This nanostructured material exhibits excellent displacement under an external electric field, therefore refers as electroactive nanostructured polymers (ENP). Comparison of the ENPs investigated here with EAPs previously reported, confirms that the ENP217 system with 5 wt% copolymer yields the highest areal actuation amongst all D-EAPs currently known. Dielectric strength of both ENPs (ENP of 217kDa and 161kDa molecular weights) increases with increasing copolymer fraction. The ENPs introduced here exhibit coupling efficiencies that are comparable, if not

  16. Localization of solid micro and nano-inclusions in heterophase bioplastic blends

    Science.gov (United States)

    Dil, Ebrahim Jalali

    Blending poly(lactic acid), PLA, with other high impact bioplastics has been introduced as an effective method for improving the toughness of PLA; however, this strategy considerably reduces the modulus and mechanical strength of PLA. The addition of solid particles is a well-known method for tuning the stiffness/toughness balance in toughened polymer matrices. Notwithstanding the significance of controlling the localization of solid inclusions in polymer blends, the literature is lacking a detailed analysis of the migration mechanisms and the effects of thermodynamic and kinetic parameters on the localization of solid particles in polymer blends. In this dissertation, the localization and migration of spherical micro- and nano-silica particles in two bioplastic blends of PLA/low density polyethylene (LDPE) and PLA/poly(butylene adipateco-terephthalate), PBAT, were studied. In the first part of this work, a detailed study on the miscibility and morphology development in the PLA/PBAT blend was carried out. The interfacial tension between PLA and PBAT was determined to be 0.6 +/- 0.15 mN/m by fitting Palierne's model on the rheological data. The miscibility of PLA/PBAT was then examined by studying the shift in the glass transition temperature (Tg) of the polymer phases at different blend compositions. The obtained results indicate a limited one-way partial miscibility of PBAT molecules in the PLA-rich phase. This partial miscibility depends significantly on the molecular weight of PBAT, which underlines its entropic nature. The morphology analysis of the blend samples revealed that the dispersed phase in PLA/PBAT blends exists in the form of fibers, even at low compositions of 1 vol.% of the dispersed phase. Finally, the co-continuity region in PLA/PBAT blends was determined using a rheological approach and it was shown that PLA/PBAT has a wide symmetric co-continuous region located between 30-40 and 60-70 vol.% of PBAT. In the second part of this project, the

  17. Development of Modified Pag (Polyalkylene Glycol) High VI High Fuel Efficient Lubricant for LDV Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gangopadhyay, Arup [Ford Motor Company, Dearborn, MI (United States); McWatt, D. G. [Ford Motor Company, Dearborn, MI (United States); Zdrodowski, R. J. [Ford Motor Company, Dearborn, MI (United States); Liu, Zak [Ford Motor Company, Dearborn, MI (United States); Elie, Larry [Ford Motor Company, Dearborn, MI (United States); Simko, S. J. [Ford Motor Company, Dearborn, MI (United States); Erdemir, Ali [Argonne National Lab. (ANL), Argonne, IL (United States); Ramirez, Giovanni [Argonne National Lab. (ANL), Argonne, IL (United States); Cuthbert, J. [Dow Chemical Company, Midland, MI (United States); Hock, E. D. [Dow Chemical Company, Midland, MI (United States)

    2015-09-30

    Test Procedure) metro/highway cycles. Five different PAG chemistries were selected by varying the starting alcohol, the oxide monomers (ethylene oxide, propylene oxide, or butylene oxide), capped or uncapped, homopolymer or random copolymer. All formulations contained a proprietary additive package and one which contained additional antiwear and friction modifier additives. Laboratory bench tests (Pin-on-Disk, High Frequency Reciprocating Rig (HFRR), Block-on-Ring, Mini-Traction Machine (MTM) identified formulations having friction, wear, and load carrying characteristics similar to or better than baseline GF-5 SAE 5W-20 oil. Motored valvetrain and motored piston ring friction tests showed nearly 50% friction reduction for some of the PAG formulations compared to GF-5 SAE 5W-20 oil. Motored engine tests showed up to 15% friction benefit over GF-5 SAE 5W-20 oil. It was observed that friction benefits are more related to PAG base oil chemistry than their lower viscosity compared to GF-5 SAE 5W-20 oil. Analysis of wear surfaces from laboratory bench tests and bucket tappets from motored valvetrain tests confirmed the presence of PAG molecules. The adsorption of these polar molecules is believed to be reason for friction reduction. However, the wear surfaces also had thin tribo-film derived from additive components. The tribo-film consisting of phosphates, sulfides, and molybdenum disulfide (when molybdenum additive was present) were observed for both GF-5 SAE 5W-20 and PAG fluids. However, when using PAG fluids, motored valvetrain tests showed high initial wear, which is believed to be due to delay in protective tribo-film formation. After the initial wear, the wear rate of PAG fluids was comparable to GF-5 SAE 5W-20 oil. The PAG oil containing additional antiwear and friction reducing additives showed low initial wear as expected. However, when this oil was evaluated in Sequence IVA test, it showed initially low wear comparable to GF-5 oil but wear accelerated with oil

  18. Spectroelectrochemical Sensor for Pertechnetate Applicable to Hanford and Other DOE Sites

    Energy Technology Data Exchange (ETDEWEB)

    Heineman, William R; Seliskar, Carl J; Bryan, Samuel A

    2012-09-18

    The general aim of our work funded by DOE is the design and implementation of a new sensor technology that offers unprecedented levels of specificity needed for analysis of the complex chemical mixtures found at DOE sites nationwide. The specific goal of this project was the development of a sensor for technetium (Tc) that is applicable to characterizing and monitoring the vadose zone and associated subsurface water at the Hanford Site and other DOE sites. The concept for the spectroelectrochemical sensor is innovative and represents a breakthrough in sensor technology. The sensor combines three modes of selectivity (electrochemistry, spectroscopy, and selective partitioning) into a single sensor to substantially improve selectivity. The sensor consists of a basic spectroelectrochemical configuration that we have developed under our previous DOE grants: a waveguide with an optically transparent electrode (OTE) that is coated with a thin chemically-selective film that preconcnetrates the analyte. The key to adapting this generic sensor to detect TcO4- and Tc complexes lies in the development of chemically-selective films that preconcentrate the analyte and, when necessary, chemically convert it into a complex with electrochemical and spectroscopic properties appropriate for sensing. Significant accomplishments were made in the general areas of synthesis and characterization of polymer films that efficiently preconcentrate the analyte, development and characterization of sensors and associated instrumentation, and synthesis and characterization of relevant Re and Tc complexes. Two new polymer films for the preconcentration step in the sensor were developed: partially sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SSEBS) and phosphine containing polymer films. The latter was a directed polymer film synthesis that combined the proper electrostatic properties to attract TcO4- and also incorporated a suitable ligand for covalently trapping a