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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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Segmented block copolyetheramides based on nylon 6 and polyoxypropylene. III. SAXS analysis

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Journal of Applied polymer science 1998年第11期64卷

作者： Yeong Chool Yu Won Ho Jo Moo Sung Lee Department of Fiber and Polymer Science Seoul National University Seoul 151‐742 Korea Department of Textile Engineering Chonnam National University Kwangju 500‐757 Korea

Morphologic characteristics of segmented block copolyetheramides based on nylon 6 and polyoxypropylene (POP) were investigated as a function of the compositions and block lengths of the hard and soft segments using small angle X‐ray scattering (SAXS). Three POPs with different molecular weights were used as a soft segment. One‐dimensional correlation functions were obtained from the desmeared intensity SAXS curves using the method developed by Vonk and Kortleve. The interdomain spacings were determined from the correlation distance at the peak position of the correlation function. From the dependence of the correlation distance on soft segment content, we deduced that an increase in the hard‐segment length may lead to crystal formation by a chain‐folding mechanism. The thickness of phase boundary was determined from the smeared intensity data using the method of Koberstein. A decrease in the phase boundary thickness with increasing soft‐segment content suggests that an increase in the chain mobility by soft segment facilitates the regular arrangement of the hard segment, resulting in the formation of the hard domain with a narrow interfacial region. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2155–2163, 1997

关键词： copolyesteramides SAXS interfacial thickness morphology

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Effect of interchange reactions on the molecular weight distribution of poly(ethylene terephthalate): A Monte Carlo simulation

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Journal of polymer science 1996年第4期34卷

作者： Won Ho Jo Jae Woo Lee Moo Sung Lee Chung Yup Kim Department of Fiber and Polymer Science Seoul National University Seoul 151-742 Korea Department of Textile Engineering Chonnam National University Kwangju 500-757 Korea Polymer Materials Laboratory Korea Institute of Science and Technology Seoul 130-650 Korea

The effect of the interchange reactions of poly(ethylene terephthalate) (PET) on its molecular weight distribution (MWD) was analyzed using a Monte Carlo simulation method. Three kinds of motions, which correspond to the direct ester(SINGLEBOND)ester interchange reaction, alcoholysis, and internal alcoholysis in polyester, were performed in this simulation: bond flip, end attack, and backbite. Two systems with two different types of nonequilibrium distribution (monodisperse and bimodal distribution) were initially prepared. The initial biases from equilibrium MWD are rapidly relaxed to an equilibrium MWD as the reaction progresses. The MWD at equilibrium is well described by the most probable MWD proposed by Flory. From the polydispersity data, it is concluded that about 0.3 interchanges per segment are sufficient to equilibrate the nonequilibrium system. For the validity of the simulation, the variation of MWD of the mixtures of two PETs having different molecular weights were monitored using gel permeation chromatography. The agreement between simulation and experiment is remarkably good. © 1996 John Wiley & Sons, Inc.

关键词： poly(ethylene terephthalate) ester interchange reaction Monte Carlo simulation molecular weight distribution gel permeation chromatography

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Preparation of poly(ethylene terephthalate-co-isophthalate) by ester interchange reaction in the PET/PEI blend system

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Journal of polymer science 1998年第2期35卷

作者： Wan Shik Ha Yong Kun Chun Seung Soon Jang Do Mook Rhee Chong Rae Park Department of Fiber and Polymer Science College of Engineering Seoul National University Seoul 151-742 Korea Textile Research Department Sam Yang Group R&D Center Taejeon Korea Department of Textile Engineering College of Engineering Sung Kyun Kwan University Suwon 440-746 Korea

Optimum conditions for the synthesis of PEI of considerable molecular weight have been established. Poly(ethylene terephthalate- co -isophthalate) (PETI) has been prepared through the ester interchange reaction of a blend of poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate) (PEI). NMR analysis has indicated that the PETI changes from a block-type copolymer to a random type copolymer as the ester interchange reaction proceeds. If the reaction is limited to 20 min, the resulting PETI is crystallizable. The effects of catalysts that have been used during the synthesis of PEI on the characteristics of PETI are also discussed. © 1997 John Wiley & Sons, Inc.

关键词： PETI ester interchange reaction PET/PEI melt blend sequence randomness

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IEEE EMBS technical committee on wearable biomedical sensors & systems: position paper

IEEE EMBS technical committee on wearable biomedical sensors...

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International Workshop on Wearable and Implantable Body Sensor Networks (BSN)

作者： P. Bonato D. De Rossi A. Dittmar S. Jayaraman I. Korhonen A. Lymberis E. Me Adams Y.-T. Zhang The Harvard-MIT Division of Health Science and Technology Cambridge USA Department of PM&R Harvard Medical School Spaulding Rehabilitation Hospital Boston USA Interdepartmental Research Center Enrico Piaggio Pisa Italy LPM CNRS/INSA Lyon France School of Polymer Textile & Fiber Engineering Georgia Institute of Technology Atlanta USA Ubiquitous Computing VTT Information Technology Tampere Finland Information Society Directorate-General European Commission Brussels Belgium Joint Research Center for Biomedical Engineering Chinese University of Hong Kong China

The IEEE engineering in Medicine and Biology Society (EMBS) established a technical committee on wearable biomedical sensors and systems (WBSS) in 2004. This position paper presents the view of the technical committee on the field of wearable sensors and systems in medicine, and shortly introduces its plan of action. The purpose of the position paper is to raise awareness of the initiatives of EMBS concerning WBSS and to encourage collaborations in order to advance research and development in the field of WBSS

关键词： Biosensors Biomedical monitoring Wearable sensors Medical services textile technology Biomedical engineering Humans Medical diagnostic imaging Research and development Actuators

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Biopolymers-based microencapsulation technology for sustainable textiles development: A short review

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Case Studies in Chemical and Environmental engineering 2023年 7卷

作者： Peng, Xiongyi Umer, Muhammad Pervez, Md. Nahid Hasan, K.M. Faridul Habib, Md Ahsan Islam, Md. Shahinoor Lin, Lina Xiong, Xiaorong Naddeo, Vincenzo Cai, Yingjie Hubei Provincial Engineering Laboratory for Clean Production and High Value Utilisation of Bio-based Textile Materials Wuhan Textile University Hubei Wuhan 430200 China School of Computing Huanggang Normal University Huanggang 438000 China Sanitary Environmental Engineering Division (SEED) Department of Civil Engineering University of Salerno via Giovanni Paolo II 132 SA Fisciano 84084 Italy Fiber and Nanotechnology Program University of Sopron Sopron 9400 Hungary South China Advanced Institute for Soft Matter Science and Technology School of Emergent Soft Matter South China University of Technology Guangzhou 510640 China Department of Chemical Engineering Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh

Microencapsulation methods in product development may result in innovative products with improved stability, functionality, and active chemical release (s). Microcapsules may be made out of biopolymers instead of synthetic polymers because of their biodegradability, lower production costs, and greater accessibility. The potential of biopolymers-based microencapsulation technology in sustainable textiles is substantial despite this field only getting started. This short review explores the role of biopolymers such as chitosan, gelatin, alginate, and cellulose in microencapsulation-mediated sustainable textile technology. The long-term effects of using microencapsulation made from biopolymers are also discussed, with an eye toward sustainability. © 2023 The Authors

关键词： Cellulose Chitosan Functional textiles Microencapsulation Sustainable textiles

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Oriented noncrystalline structure in PET fibers prepared with threadline modification process

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Journal of polymer science 1996年第12期34卷

作者： Gang Wu Jiao-Dong Jiang Paul A. Tucker John A. Cuculo Department of Polymer Science 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

The development of an oriented noncrystalline phase in a semicrystalline polymer filament has been studied via X-ray scattering. These unique PET fibers contain a relatively high noncrystalline content and also have high tenacity, high modulus, and low breaking elongation. fiber properties were found to be very responsive to the oriented amorphous phase content. This phase was utilized for interpreting noncrystalline orientation in PET fibers produced by a new extrusion technique. Here, the oriented noncrystalline regions in a series of PET fibers varies from 6% to 63%, depending strongly on the production conditions. In particular, samples produced with a newly developed threadline modification process possess a high content of oriented noncrystalline polymer. Measurements such as dynamic and static mechanical properties have been performed on various samples, and these properties are related to the oriented noncrystalline phase. The results provide direct evidence for the existence of highly oriented noncrystalline material in these unique PET fibers spun with a threadline modification process. © 1996 John Wiley & Sons, Inc.

关键词： poly(ethylene terephthalate) controlled threadline dynamics orientation oriented noncrystalline phase fiber properties crystallinity

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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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