• Title/Summary/Keyword: Poly Vinyl Alcohol

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Influence of preparation parameters on rheological behavior and microstructure of aqueous mixtures of hyaluronic acid/poly(vinyl alcohol)

  • Park Hyun-Ok;Hong Joung Sook;Ahn Kyung Hyun;Lee Seung Jong;Lee Seong Jae
    • Korea-Australia Rheology Journal
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    • v.17 no.2
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    • pp.79-85
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    • 2005
  • Aqueous mixtures of hyaluronic acid and poly(vinyl alcohol) system and hydrogels thereof were introduced to obtain new bioartificial materials that have excellent mechanical properties, biocompatibility and enhanced rheological properties. The interactions between hyaluronic acid and poly(vinyl alcohol) and/or borax were investigated by rheological measurements. Preparation parameters of the aqueous mixtures were mixture composition, the degree of hydrolysis of poly(vinyl alcohol) and borax concentration. From the rheological behavior, it could be deduced that the key factor of the interaction between hyaluronic acid and poly(vinyl alcohol) was the hydrogen bonding between them and the effect was pronounced with borax. Enhanced viscosity was observed at the composition of $20wt\%$ of hyaluronic acid solution and $80wt\%$ of poly(vinyl alcohol) and borax solution. Rheological properties were influenced by the degree of hydrolysis of poly(vinyl alcohol) and borax concentration. As the degree of hydrolysis and borax concentration increased, rheological properties increased due to the increased hydrogen bonding and networking of hyaluronate aggregates. Physical hydrogels from hyaluronic acid and poly(vinyl alcohol) were prepared and the composition dependence of the gels was rheologically investigated as well.

Effect of Poly(vinyl alcohol) and Poly(vinyl alcohol) Mono Thiol on the Stability Properties of Poly(vinyl acetate) Latex (폴리비닐알코올과 폴리비닐알코올모노티올이 폴리초산비닐 라텍스의 안정성에 미치는 영향)

  • 이서용;박이순
    • Polymer(Korea)
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    • v.24 no.5
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    • pp.579-588
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    • 2000
  • The effects of protective colloids on the colloid stability of poly(vinyl acetate) (PVAc) latex was investigated. The stability of PVAc latex in reactive poly(vinyl alcohol) mono thiol (PVALT) (DP=1080) having 78.4% saponification value was better than poly (vinyl alcohol)(PVA) (DP=1100) having 81.6% saponification value. The colloidal stability of PVAc latex particles improved drastically with increase of the reactive PVALT. The particle surface morphology of PVAc latex was examined by transmission electron microscopy (TEM). It was shown that particle size of 1ha latexes decreased with increasing reactive PVALT concentration. Therefore, the stabilities of latex for reactive PVALT protective colloid was superior to that of PVA ones. This result is due to the introduction of many thiol groups that induce chemical bonds at PVAc latexes surface, so that the formation of PVALT-b-PVAc block copolymer via the reaction of PVAc with reactive PVALT. In addition, zeta potential of the PVAc latexes decreased with increasing sodium carbonate concentration.

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Synthesis and Characterization of Poly(vinyl alcohol-b-styrene) via Atom Transfer Radical Polymerization and Saponification

  • Li, Guang-Hua;Cho, Chang-Gi
    • Macromolecular Research
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    • v.10 no.6
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    • pp.339-344
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    • 2002
  • Poly(vinyl alcohol-b-styrene) (poly(VA-b-St)) diblock copolymer containing high syndiotactic poly (vinyl alcohol) (PVA) was synthesized by the saponification of poly(vinyl pivalate-b-styrene) (poly(VPi-b-St)). For the block copolymer, poly(vinyl pivalate) (PVPi) with trichloromethyl end group was obtained via telomerization of vinyl pivalate with carbon tetrachloride as a telogen and 2,2-azobisisobutyronitrile (AIBN) as an initiator. Then resulting poly(vinyl pivalate) with trichloromethyl end group was used as an effient macroinitiator for the synthesis of poly(VPi-b-St) using atom transfer radical polymerization (ATRP) in the presence of CuCl/2,2'-bipyridine at 130 $^{\circ}C$. The poly(vinyl pivalate) macroinitiator, poly(VPi-b-St), poly(VA-b-St) were characterized by GPC, FT-IR and $^1$H-NMR. And the analysis showed that integrity of the block copolymer was maintained during saponification reaction.

Effect of Poly(vinyl alcohol) on the Thermally Induced Conformational Change of Poly(D-Glutamic acid)

  • Cho Chong-Su
    • Bulletin of the Korean Chemical Society
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    • v.3 no.2
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    • pp.60-66
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    • 1982
  • In relation to denaturation of proteins, thermally induced conformational change of poly(D-glutamic acid) was studied in the presence of poly(vinyl alcohol) at low pH, where poly(D-glutamic acid) undergoes a helix-to-${\beta}$ transition without any other polymer. In a dilute solution, poly(vinyl alcohol) enhanced the ${\alpah}-to-{\beta}_1$ transition of poly(D-glutamic acid) due to intermolecular interaction between the two polymers. On the other hand, this conformational change was interrupted to a large extent in a concentrated solution, due to the interpenetration of poly(vinyl alcohol) chain into poly(D-glutamic acid) chain which prevented the intramolecular association of poly(D-glutamic acid) chain. A conformational change from ${\beta}_1\;to\;{\beta}_2$ of poly(D-glutamic acid) was observed for the films obtained by casting during annealing the mixture solutions. The ${\beta}_2$ content in the cast film increased with increasing poly(vinyl alcohol) content in the mixture.

Performance Study of Membrane Capacitive Deionization Installed with Sulfonated Poly(ether ether ketone) and Poly(vinyl amine)/poly(vinyl alcohol) Membranes (Sulfonated Poly(ether ether ketone) 및 Poly(vinyl amine)/poly(vinyl alcohol) 혼합막이 장착된 막결합형 축전식 탈염공정의 성능 연구)

  • Kim, Ka young;Rhim, Ji Won
    • Membrane Journal
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    • v.26 no.1
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    • pp.62-69
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    • 2016
  • In this study, sulfonated poly(ether ether ketone) (SPEEK) as cation exchange membrane and blended and crosslinked poly(vinyl amine) (PVAm) with poly(vinyl alcohol) (PVA) membrane as anion exchange membrane were used and then the performance experiments of the membrane capacitive deionization (MCDI) installed with both membranes were carried out. The newly prepared anion exchange membrane were characterized through water content, ion exchange capacity and FT-IR. The crosslinking time of 3 h to 5 h indicated that the salt removal was reduced from 81.3, 65.7% to 53.8%. The effect of PVAm contents from 40, 60, to 80% on the salt removal was shown 81.3, 75.2 and 37.7%, respectively. As a result, it was concluded that the crosslinking time and the content of PVAm had an influence on the salt removal efficiency.

Influence of the Syndiotacticity of Poly(vinyl alcohol) block on the formation of micelles for Poly(vinyl alcohol-b-styrene) (Poly(vinyl alcohol) block의 신디오탁틱이 Poly(vinyl alcohol-b-styrene)의 micelle형성에 미치는 영향)

  • 이광화;조창기
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.04a
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    • pp.291-292
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    • 2003
  • Amphiphilic block copolymer는 self-assembly특성을 가지고 있기 때문에 선택된 용매 속에서 nanoscale-domain 즉 micelle을 형성할 수 있다. 이러한 특성은 기타 불용성 물질을 가용화하고 colloidal particle을 안정화시키거나 micro-emulsion을 형성할 수 있어 pharmaceutics, drug delivery system등 영역, 그리고 emulsion stabilizer, thickener, dispersion agent등으로 사용될 수 있다. (중략)

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Synthesis of High Molecular Weight Poly(vinyl Alcohol) with High Yield by 1 Batch Suspension Polymerization and Saponification and Its Characterization (일욕 현탁중합과 비누화에 의한 고분자량 폴리비닐알코올의 고수율 제조 및 그의 특성해석)

  • Lee, Hee-Won;Lyoo, Won-Seok
    • Proceedings of the Korean Fiber Society Conference
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    • 2001.10a
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    • pp.187-190
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    • 2001
  • The poly(vinyl alcohol) (PVA) fiber is recognized as the best candidate because of its good machanical properties together with excellent resistance to alkalis[1-5]. PVA cannot be prepared by the direct polymerization due to tautomerism of vinyl alcohol monomer. Thus PVA is obtained by the saponification of poly(vinyl ester) like poly(vinyl acetate) (PVAc). (omitted)

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Non-Newtonian Rheological Properties of Poly(vinyl alcohol) hydrogel (Poly(vinyl alcohol) hydrogel의 비 뉴톤 유변학적인 성질)

  • Kim, Nam-Jeong
    • Elastomers and Composites
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    • v.44 no.3
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    • pp.323-328
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    • 2009
  • The rheological properties of complex materials such as polymer melts show complicated non-Newtonian flow phenomena when they are subjected to shear flow. These flow properties are controlled by the characteristics of flow units and the interactions among the flow segments. The non-Newtonian flow curves of poly(vinyl alcohol) hydrogel were obtained in various concentrations and temperatures by using a cone-plate rheometer. By applying non-Newtonian flow equation to the flow curves for PVA hydrogel samples, the rheological parameters were obtained. The PVA hydrogel samples are shear thinning under increasing shear rate modes which result in thixotropic behavior.

폴리프로필렌의 친수화 개질 -Polypropylene-poly(vinyl alcohol-co-ethylene) 블렌드의 특성-

  • 임상규;손태원
    • Proceedings of the Korean Fiber Society Conference
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    • 1996.04a
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    • pp.64-68
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    • 1996
  • PP-EVOH(poly(vinyl alchol-co-ethylene)) blends were prepared by the mixing of polypropylene and poly(vinyl alcohol-co-ethylene) containing 38mol% of ethylene units (EVOH38) at melt state above PP melting temperature. The materials were characterized by using dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and contact angle measurement to detemine the glass transition, meltin, decomposition temperatures, and wettability respectively. From the results, PP-EVOH(poly(vinyl alcohol-co-ethylene)) blends exgibits partial miscibility.

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Studies on the Addition of the Hydroquinonesulfonic Acid to Poly(vinyl alcohol)/poly(acrylic acid-co-maleic acid) Membranes to Improve the Ion Conductivity for Fuel Cell Applications (Poly(vinyl alcohol)/poly(acrylic acid-co-maleic acid) 이온교환막에 이온전도도 향상을 hydroquinonesulfonic acid 첨가 연구)

  • 임지원;황호상
    • Membrane Journal
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    • v.14 no.1
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    • pp.44-52
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    • 2004
  • This paper concerns the development of a cationic polymeric membranes for direct methanol fuel cell. The crosslinked poly(vinyl alcohol) (PVA) membranes with poly(acrylic acid-co-maleic acid) (PAM) and hydroquinonesulfonic acid (HQSA) as the crosslinking agents were prepared according to the amount of crosslinking agents. The resulting membranes were characterized in terms of methanol permeability, proton conductivity, water content and ion exchange capacity. The methanol permeability and proton conductivity increased with increasing PAM content up to 9 wt% and then decreased. This trend is considered the effect of the cross linking rather than the introduction of hydrophilic groups. When the HQSA contents were varied, no interesting increases of proton conductivity, water content and ion exchange capacity were found.