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Relationships between antithrombogenicity and surface free energy of regenerated silk fibroin films

fibers and polymers 2001年第2期2卷 58-63页

作者： Park, Won Ho Ha, Wan Shik Ito, Hiraku Miyamoto, Takeaki Inagaki, Hiroshi Noishiki, Yasuharu Department of Textile Engineering Chungnam National University Taejon Korea Department of Fiber and Polymer Science Seoul National University Seoul Korea Saint Agnes’ Junior College Osaka Japan Institute for Chemical Research Kyoto University Uji Kyoto Japan First Department of Surgery School of Medicine Yokohama City University Yokohama Japan

Silk fibroin (SF) was dissolved in calcium chloride/ethanol/water mixture (1/2/8 in mole ratio) at 70°C for 4 h. The dissolved silk fibroin was regenerated by casting the dialyzed solution into the films. The films were treated with 50% aqueous solution of methanol for different times, and their antithrombogenicity was evaluated byin vitro andin vivo *** vivo blood tests were made by a method of peripheral vein indwelling suture. It was found that the silk fibroin had a good anti-thrombogenicity and an absorbability even though the polymer showed foreign body reaction. Finally, the blood compatibilty of silk fibroin films which were subjected to structural change by the methanol treatment, was examined in connection with their interfacial surface energy, and a correlation between these properties was found to be present.

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Formation of metal complex in a poly(hydroxamic acid) resin bead

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fibers and polymers 2001年第1期2卷 13-17页

作者： Lee, Taek Seung Jeon, Dong Won Kim, Jai Kyeong Hong, Sung Il Organic & Optoelectronic Materials Lab. Department of Textile Engineering Chungnam National University Taejon Korea Department of Clothing and Textiles Ewha Womans University Seoul Korea Electronic Materials and Devices Research Center Korea Institute of Science and Technology Cheongryang Seoul Korea Department of Fiber and Polymer Science Seoul National University Seoul Korea

Poly(hydroxamic acid) resin beads were prepared and complexed with various metal ions. We used IR spectroscopy to investigate the structure of metal complex. It proved that the products formed by introduction of metal ions gave stable and colored complex. It was found that the resin bead as synthesized would be a good column packing material for continuous extraction. Energy dispersive spectroscopy was used to study the distribution of metal ions in the resin matrix. It could be tentatively concluded that adsorption and diffusion of metal ions in the chelating resins mainly depended on the loading of the resin matrix which indicated interacting sites with metal ions.

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Effect of comonomers on the melt intercalation of styrenics/organosilicate hybrids

American Chemical Society, Polymer Preprints, Division of Po...

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American Chemical Society, polymer Preprints, Division of polymer Chemistry 2000年第1期41卷 598-599页

作者： Jo, Won Ho Yoon, Jong Tae Lee, Moo Sung Ko, Moon Bae Hyperstructured Organ. Mat. Res. C. Dept. of Fiber and Polymer Science Seoul National University Seoul 151-742 Korea Republic of Department of Textile Engineering Adv. Materials Research Institute Chonnam National University Kwangju 500-757 Korea Republic of Polymer Hybrid Research Center Korea Inst. of Sci. and Technology Seoul 130-650 Korea Republic of

The effect of comonomers on the intercalation behavior of the styrenics/organosilicate hybrids was investigated because they can change the degree of intermolecular interaction and the stress-transfer during mixing. Two different polar comonomers, acrylonitrile (AN) and methylvinyloxazoline (OZ), were incorporated into non-polar polystyrene (PS) chains. The degree of intercalation was estimated using an X-ray diffraction technique and the interaction between polymer and montmorillonite was investigated using a Fourier transform infrared spectroscopy.

关键词： Reinforced plastics

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Biodegradable dextran-polylactide hydrogel network and its controlled release of albumin

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Journal of Biomedical Materials Research Part B: Applied Biomaterials 2000年第1期54卷

作者： Yeli Zhang Chih-Chang Chu Fiber and Polymer Science Program Department of Textiles and Apparel & Biomedical Engineering Program Cornell University Ithaca New York 14853-4401

The objective of this paper was to study the release of bovine serum albumin (BSA) from a series of biodegradable hydrogels having a wide range of hydrophilicity to hydrophobicity, swelling, and biodegradation properties. BSA was incorporated into a series of biodegradable hydrogels made from a dextran derivative of allyl isocyanate (dex-AI, as the hydrophilic constituent) and poly( DL -lactic acid) diacrylate macromer (PDLLAM, as the hydrophobic constituent). The release kinetics of BSA from these dex-AI/PDLLAM hydrogels was studied. Laser confocal scanning microscopy was used to investigate the morphological change of the hydrogels, as well as BSA distribution in the hydrogels, as a function of dex-AI to PDLLAM composition ratio and incubation time. We found that the incorporation of PDLLAM into dex-AI reduced the initial burst release of BSA due to its more homogeneous distribution in the hydrogels. As the PDLLAM component increased, the rate of formation of a loose three-dimensional (3D) network structure increased; consequently, the sustained rate and extent of BSA release increased. Both release index and diffusion coefficient (from release kinetics data) increased as the PDLLAM component increased in the hydrogels. The data suggest that the release of BSA was controlled by both diffusion of BSA through swelling of the hydrophilic phase during an early stage, and degradation of the hydrophobic phase during a late stage, and also that the magnitude of diffusion versus degradation controlled release is dependent on composition ratio and immersion time. © 2000 John Wiley & Sons, Inc.

关键词： dextran poly(lactic acid) hydrogel controlled release albumin laser confocal microscope biodegradation

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Synthesis and characterization of biodegradable network hydrogels having both hydrophobic and hydrophilic components with controlled swelling behavior

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Journal of polymer science 2000年第24期37卷

作者： Yeli Zhang Chee-Youb Won Chih-Chang Chu Fiber and Polymer Science Program Department of Textiles and Apparel & Biomedical Engineering Program Cornell University Ithaca New York 14853-4401

A new class of biodegradable hydrogels, consisting of hydrophobic poly( D , L )lactic acid (PDLLA) and hydrophilic dextran segments with a polymer network structure, was synthesized with UV photopolymerization. Unsaturated vinyl groups first were introduced onto the PDLLA and dextran polymer backbones, then followed by a crosslinking reaction of diacrylate-terminated PDLLA and dextran acrylate. The chemical crosslinking forced the hydrophobic PDLLA and hydrophilic dextran segments to mix with each other in the network hydrogels. The new polymers were characterized by standard polymer characterization methods such as NMR, Fourier transform infrared spectroscopy, and gel permeation chromatography. The effects of reaction time, temperature, and molar ratio of the reactants on the incorporation of acrylate onto the polymer backbone were examined. A series of hydrogels with different dextran/PDLLA composition ratios was prepared, and their swelling behaviors were studied. These new bicomponent network hydrogels had a wide range of hydrophilicity to hydrophobicity that was difficult to achieve in totally hydrophilic hydrogels. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4554–4569, 1999

关键词： biodegradable hydrogel dextran poly(D,L)lactic acid polymer network photocrosslinking acrylate biodegradable polymers swelling ratio

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Synthesis and absorbency of a superabsorbent from sodium starch sulfate‐g‐polyacrylonitrile

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Journal of Applied polymer science 2000年第8期79卷

作者： Doo‐Won Lim Hyun Suk Whang Kee‐Jong Yoon Sohk‐Won Ko Department of Fiber and Polymer Science Seoul National University Seoul 151‐742 Korea College of Engineering Textile Engineering Dankook University Seoul 140‐714 Korea

A sodium starch sulfate–based superabsorbent was synthesized to improve water and saline absorbencies. A sodium starch sulfate with high degree of substitution was synthesized by the reaction of starch gelatinized with dimethyl acetamide (DMAc)/lithium chloride (LiCl) and a dimethyl formamide–sulfur trioxide (DMF–SO 3 ) complex. The sodium starch sulfate was then graft‐polymerized with acrylonitrile and the nitrile groups of the sodium starch sulfate‐ g ‐polyacrylonitrile were converted to a mixture of hydrophilic carboxamide and carboxylate groups by alkaline hydrolysis. The hydrolyzed sodium starch sulfate‐ g ‐polyacrylonitrile copolymer exhibited improved water and saline absorbencies compared with that of existing starch‐based superabsorbents, resulting from the presence of sulfate groups. The maximum water and saline absorbencies of the sodium starch sulfate–based superabsorbent were 1510 and 126.4 g/g, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1423–1430, 2001

关键词： sodium starch sulfate superabsorbent DMAc/LiCl DMF–SO3 complex acrylonitrile polyacrylonitrile

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Synthesis and characterization of biodegradable poly(L-aspartic acid-co-PEG)

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Journal of polymer science 2000年第16期36卷

作者： Chee-Youb Won Chih-Chang Chu Jong Doo Lee Fiber and Polymer Science Program and Biomedical Engineering Program Cornell University Ithaca New York 14853 Department of Materials Science and Engineering Cornell University Ithaca New York 14853

The melt polycondensation reaction of the prepolymer prepared from N -(benzyloxycarbonyl)- L -aspartic acid anhydride ( N -CBz- L -aspartic acid anhydride) and low molecular weight poly(ethylene glycol) (PEG) using titanium isopropoxide (TIP) as a catalyst produced the new biodegradable poly( L -aspartic acid- co -PEG). This new copolymer had pendant amine functional groups along the polymer backbone chain. The optimal reaction conditions for the preparation of the prepolymer were obtained by using a 0.12 mol % of p -toluenesulfonic acid with PEG 200 for 48 h. The weight-average molecular weight of the prepolymer increased from 1,290 to 31,700 upon melt polycondensation for 6 h at 130°C under vacuum using 0.5 wt % TIP as a catalyst. The synthesized monomer, prepolymer, and copolymer were characterized by FTIR, 1 H- and 13 C-NMR, and UV spectrophotometers. Thermal properties of the prepolymer and the protected copolymer were measured by DSC. The glass transition temperature ( T g ) of the prepolymer shifted to a significantly higher temperature with increasing molecular weight via melt polycondensation reaction, and no melting temperature was observed. The in vitro hydrolytic degradation of these poly( L -aspartic acid- co -PEG) was measured in terms of molecular weight loss at different times and pHs at 37°C. This pH-dependent molecular weight loss was due to a simple hydrolysis of the backbone ester linkages and was characterized by more rapid rates of hydrolysis at an alkaline pH. These new biodegradable poly( L -aspartic acid- co -PEG)s may have potential applications in the biomedical field. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2949–2959, 1998

关键词： aspartic acid anhydride poly(ethylene glycol) poly(L-aspartic acid-co-PEG) biodegradable polymers

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Hydrolysis of biodegradable polymers by superoxide ions

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Journal of polymer science 2000年第18期37卷

作者： K. H. Lee C. Y. Won C. C. Chu Ivan Gitsov Fiber Science Program Department of Textile and Apparel and Biomedical Engineering Program Cornell University Ithaca NY 14853-4401 Department of Chemistry State University of New York College of Environmental Science and Forestry Syracuse NY 13210 Cornell Center for Materials Research and Department of Chemistry and Chemical Biology Cornell University Ithaca NY 14853-1301

The objective of this study was to examine the reactivity of superoxide ion as an oxygen nucleophile towards biodegradable biomaterials having an aliphatic polyester structure, such as poly( D , L -Lactide) (PDLLA). The changes in molecular weights and thermal properties of PDLLA were studied as a function of the superoxide ion concentration, hydrolysis time, and hydrolysis temperature. The superoxide ion induced fragmentation of PDLLA yielded a mixture of various species with different chain length. A combined size exclusion chromatography (SEC) method with a chemical tagging by phenyl isocyanate revealed that the structure of the oligomer species with the lowest molecular weight formed in the superoxide ion induced degradation mixture was linear. The significant reduction in T g was consistent with the significant reduction in the molecular weight of PDLLA. The linear low molecular fragments (dimers and trimers) in the reaction mixture could act as an internal plasticizers to enhance the T g reduction by increasing the free volume of chain ends. The relationship of T g with molecular weight of PDLLA followed the general theory of Fox–Flory. The mechanism of simple hydrolysis of ester by superoxide ion proposed by Forrester et al. was modified to interpret the data obtained from the synthetic biodegradable polymers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3558–3567, 1999

关键词： superoxide ion biodegradable polymers hydrolysis polylactide degradation

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Photoactive polyamideimides synthesized by the polycondensation of azo‐dye diamines and rosin derivative

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Journal of Applied polymer science 2000年第4期79卷

作者： Seung Ju Kim Beom Jun Kim Dong Wook Jang Se Hun Kim Soo Young Park Ju‐Hyun Lee Sin‐Doo Lee Dong Hoon Choi Department of Fiber and Polymer Science Seoul National University Seoul 151‐742 South Korea School of Electrical Engineering Seoul National University Seoul 151‐742 South Korea Division of Textile Chemistry & Industrial Engineering Kyung Hee University Kyungki 449‐701 South Korea

New rosin‐based photoactive polyamideimides (PAI‐a and PAI‐b) with a large second‐order nonlinear optical coefficient and photoinduced birefringence were synthesized by the polycondensation of rosin–maleic anhydride adduct (RMA) with azo‐dye diamines, 2‐(2‐{ethyl‐[4‐(4‐nitrophenylazo)phenyl]aminoethoxy)benzene‐1,4‐diamine (4a) or 2‐(2‐{ethyl‐[4‐(4‐methylsulfonylphenylazo)phenyl]amino}ethoxy)benzene‐1,4‐diamine (4b). Due to the bulky alicyclic structure of the rosin, these polymers were highly soluble in organic solvents and could easily be processed by spin‐coating into thin films of high optical quality. Fabricated polymer films were very smooth, tough, adhesive to the substrate, and optically clear. Second‐order nonlinear optical coefficients ( d 33 ) of the corona‐poled PAI‐a and PAI‐b films were 83 and 54 pm/V, respectively, at the fundamental wavelength of 1064 nm. Birefringences as high as 0.072 for PAI‐a and 0.035 for PAI‐b could be induced and erased repeatedly by the irradiation of linearly polarized and circularly polarized 532‐nm light, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 687–695, 2001

关键词： rosin nonlinear optical photoinduced birefringence azo polyamideimide

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Structure development and physical properties achieved in the drawing and/or annealing of PEN fibers

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Journal of polymer science 2000年第11期38卷

作者： Gang Wu Ming Liu Xiaoning Li John A. Cuculo College of Material Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Department of Fibrous Material Engineering Beijing Institute of Clothing Technology Beijing 100029 China Fiber & Polymer Science Program College of Textiles North Carolina State University Raleigh North Carolina 27695

As-spun poly(ethylene-2,6-naphthalate) (PEN) fibers (i.e., precursors) prepared from high molecular weight polymer were drawn and/or annealed under various conditions. Structure and property variations taking place during the treatment process were followed via wide-angle X-ray scattering (WAXS), small-angle X-ray scattering, differential scanning calorimetry (DSC), and mechanical testing. Both the WAXS and DSC measurements of the cold-drawn samples stretched from a low-speed-spun amorphous fiber indicate that strain-induced crystallization can occur at a temperature below the glass-transition temperature and that the resultant crystal is in the α-form modification. In contrast, when the same precursor was subjected to constrained annealing, its amorphous characteristics remained unchanged even though the annealing was performed at 200 °C. These results may imply that the application of stretching stress is more important than elevated temperatures in producing α-form crystallization. The crystalline structure of the hot-drawn samples depends significantly on the morphology of the precursor fibers. When the precursor was wound at a very low speed and in a predominantly amorphous state, hot drawing induced the formation of crystals that were apparently pure α-form modification. For the β-form crystallized precursors wound at higher speeds, a partial crystalline transition from the β form to the α form was observed during the hot drawing. In contrast with the mechanical properties of the as-spun fibers, those of the hot-drawn products are not improved remarkably because the draw ratio is extremely limited for most as-spun fibers in which an oriented crystalline structure has already formed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1424–1435, 2000

关键词： poly(ethylene-2,6-naphthalate) fiber drawing annealing structural change crystalline transition

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