• Title, Summary, Keyword: PVA

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A study on the Preparation Methods of the Immobilized Encapsulation PVA-media for Wastewater Treatment (포괄고정화 PVA-gel의 물리적 특성 연구)

  • Lee, Eun-Woo;Chang, In-Soung;Chung, Son-Young;Nam, Byeong-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.6 no.2
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    • pp.116-121
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    • 2005
  • Immobilization technique by PVA encapsulation is an effective alternative for wastewater treatment. However little information is available about the effect of PVA characteristics on physical properties as an encapsulation media. This study aims at investigating the effect of the preparation methods of PVA and filler addition to media on the solubility of PVA. The solubility decreased as the freezing temperature decreased and the vacuum-drying was applied. Addition of the PAC (Powered Activated Carbon) and organoclay decreased the solubility of the PVA gels. Organoclay was more effective for lowering the solubility about 25% than the PAC. Nitrification with the PVA-coating media was less sufficient than with the polyurethane media due to the mass transfer restriction for oxygen and nutrients.

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Blood Compatibility of Polyurethane-poly(vinyl alcohol) Polymer Blends (폴리우레탄-폴리비닐알콜 블렌드의 혈액적합성)

  • 김승수;유영미;신재섭;정규식
    • Polymer(Korea)
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    • v.24 no.1
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    • pp.82-89
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    • 2000
  • The blood compatibilities of PU/PVA polymer blends with different mixing ratios were evaluated using various methods, such as fibrinogen adsorption, plasma recalcification time, platelet adhesion, whole blood clotting time, and complement activation. In addition, PVA on the surface of the polymer blends was crosslinked by glutaraldehyde to restrain the mobility of PVA molecules for characterizing the effect of PVA in the polymer blends on blood compatibility. The fibrinogen adsorption on the polymer blends decreased with the increase of PVA amount in the polymer blends. The plasma recalcification times of the polymer blends with 10-50 wt% PVA were longer than those of PU, PVA, and polymer blends with higher amount of PVA. The morphological changes and adhesion of platelets on the polymer blends with 30-50 wt% PVA were less than those on the other materials. The blood clotting times and complement activation on the polymer blends with 30-50 wt% PVA were reduced, compared to the other materials. On the other hand, the blood compatibility of the crosslinked polymer blends was relatively decreased, compared to the non-crosslinked ones. According to these experimental results, the blood compatibility of the polymer blends with 30-50 wt% PVA was better than that of the other materials and such a blood compatibility of the polymer blends might be related to the mobility of PVA molecules on the surface.

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Review on PVA as a Water Soluble Packaging Material (수용성 폴리비닐알콜(PVA) 포장소재의 이용)

  • Lee, Ji-Youn;Jang, Si-Hun;Park, Su-Il
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.15 no.1
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    • pp.25-32
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    • 2009
  • It is now widely recognized that the disposal of packaging waste is an increasing environmental concern. Recent interest in polymer waste management of packaging materials has added incentive to the research. Poly(vinyl alcohol) is a readily biodegradable water-soluble polymer. However, this polymer cannot be processed by conventional extrusion technologies because the melting point of PVA is close to its decomposition temperature. Therefore, PVA films have been mostly prepared by solvent casting from water. Applications of PVA include sizing, binders, fibers, and films for agricultural chemicals and hospital laundry bags. A better understanding of PVA films, which also play important roles in the degradation of plastics, will expand the usage of PVA. Composite films based on PVA generally exhibit better mechanical and thermal properties than pure PVA. The aim of this review article is to review types, formation, and properties of PVA films and PVA based composite films used in packaging related researches.

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Characterization of PVA Degrading Enzymes from Microbacterium barkeri KCCM 10507 and Paenibacillus amylolyticus KCCM 10508 (Microbacterium barkeri KCCM 10507 및 Paenibacillus amylolyticus KCCM 10508에서 분비되는 PVA 분해 효소의 특성 연구)

  • Choi Kwang-Keun;Kim Sang-Yong;Lyoo Won-Seok;Lee Jin-Won
    • KSBB Journal
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    • v.21 no.1
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    • pp.54-58
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    • 2006
  • The purpose of this study is to search the characteristics of PVA degrading enzymes which were obtained from Microbacterium barkeri KCCM 10507 and Paenibacillus amylolyticus KCCM 10508, respectively. As a result of the PVA degrading test using crude enzymes, the activity of SAO (secondary alcohol oxidase) was maximized after 2 or 3 days from start of the test, while the activity of BDH (${\beta}$-diketone hydrolase) was gradually increased during the test. Activities of them were maintained in the presence of PVA, but as PVA was gradually degraded, their activity was decreased. PVA was inoculated again into the media, their activity was revealed. This result indicated that above two different enzymes were closely connected with PVA degradation and PVA was degraded by activity of SAO and BDH. Maximum activity of them was 1.5-1.8 unit for SAO and 1.5-2.0 unit for BDH under $35^{\circ}C$ and pH 7.8-8.8, respectively.

Isolation and Characteris tics of Polyvinyl Alcohol Degrading Bacteria (폴리비닐 알콜 분해균주의 분리 및 특성)

  • 정선용;조윤래;김정목;조무환
    • Microbiology and Biotechnology Letters
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    • v.20 no.1
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    • pp.96-101
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    • 1992
  • Two strains of polyvinyl alcohol (PVA) utilizing bacteria were isolated from the waste water and soil. These strains, G5Y and PW, were able to utilize PVA symbiotically as a carbon source, but could not utilize PVA separately. In the mixed culture of these strains, 0.5 percent of PVA was almost completely degraded in 3 days. Effect of degree of PVA polymerization on the its utilization was examined, and there was no remarkable difference among three kind of PVA (PVA 500, 1500, a d 2000). These bacteria were able to utilize PV,4 in the desizing waste water of factory as well as enrichment PVA medium. These strains, C5Y and PW, were identified as Pseudomonas cepucia and Pseudomonus pseudomallei, respectively, based on morpholofical and biological characteristics.

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Interfacial Electric Property of PVA/PVAc Particles (PVA/PVAc 입자의 계면 전기적 성질)

  • Lee, Ha-Na;Lee, Jae-Woong;Kim, Ji-Young;Lee, Won-Chul;Kim, Sam-Soo
    • Textile Coloration and Finishing
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    • v.20 no.6
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    • pp.8-17
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    • 2008
  • Poly (vinyl acetate) (PVAc) was used as a precursor of PVA/PVAc (skin/core) bicomponent. In order to investigate the possibility of PVA particles for electrical applications, PVA/PVAc particles were produced with an emulsifier, SDS (Sodium Dodecyl Sulfate) and an initiator, V-50 (2,2'-azobis(2-amidinopropane)digydrochloride). In this study, we investigated the electrical property of PVA/PVAc (skin/core) particles. The hydroxyl group of the PVA/PVAc (skin./core) was confirmed by the analysis of PVAc and PVA/PVAc (skin/core) using Fourier Transform Infrared Spectroscopy (FT-IR). The zeta-potential of the PVA/PVAc (skin/core) and PVAc has similarity; however, charge control agent (CCA) treated PVA/PVAc (skin/core) particles has lower zeta-potential than untreated PVA/PVAc particles. The zeta-potential (negative values) of the PVA/PVAc (skin/core) were enhanced in proportion to the increased concentration of CCA.

Structure-Property Relationship of PVA-SbQ Water Soluble Photosensitive Polymer and its Application to Screening Process of Color Monitor (PVA-SbQ 수용성 감광성 고분자의 구조와 감도관계 및 칼라 수상관 스크린 공정에의 응용)

  • Park, Lee Soon;Han, Yoon Soo;Kim, Bong Chul
    • Applied Chemistry for Engineering
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    • v.7 no.2
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    • pp.379-386
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    • 1996
  • Photosensitive compound, 1-methyl-4-[2-(4-diethylacetylphenyl)ethenyl] pridinium methosulfate(SbQ-A salt), was synthesized from dimethyl sulfate, terephthalaldehyde mono-(diethylacetal) and 4-picoline. SbQ-A salts were reacted with poly(vinyl alcohol)s, (PVA) in aqueous solution with phosphoric acid as catalyst to give photosensitive PVA-SbQ with different SbQ content and molecular weight. Relative photosensitivity of PVA-SbQ was determined by gray scale(GS) method. The rotative sensitivity of PVA-SbQ increased with increasing amount of bound SbQ in the case of high molecular weight(MW=77,000-79,000g/mol) as substrate and decreased with decreasing molecular weight of PVA with about constant(1.3mol%) amount of bound SbQ. The most sensitive polymer was obtained when SbQ group content in PVA-SbQ reached about 2.63mol% in the case of high molecular weight(77,000-79,000g/mol) PVA. This sample showed 90 times greater sensitivity than dichromated PVA as reference photosensitive system. PVA-SbQ photosensitive polymer synthesized was applied to the photolithographic screening process of phosphor on the panel of cathode ray tube(CRT). Phosphor slurry was made with PVA-SbQ, phosphor, a small amount of surfactant and other additives using water as medium. The slurry was coated onto panel, dried by heater, exposed to UV light and then developed by distilled water. When a small amount of cationic surfactant such as cetyltrimethylammonium chloride was used in the slurry formulation, the sharpness of phosphor pattern was equal to or better than that of dichromated PVA photosensitive polymer system used currently.

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The Crosslinking Characteristic of Poly(vinyl alcohol) by Natural Dye (천연 염료에 의한 폴리(비닐 알코올)의 가교 특성)

  • Kim, Gwan-Hoon;Kim, Hyo-Gap;Kang, Ho-Jong
    • Polymer(Korea)
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    • v.35 no.1
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    • pp.72-76
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    • 2011
  • The physical properties of crosslinked poly(vinyl alcohol)(PVA) by natural dyes as crosslinking agents were investigated and a comparison was made with chemically crosslinked PVA by Polycup 172. It was found that natural anthocyanin and crocin made possible to crosslink PVA physically through the hydrogen bonding of OH in both PVA and natural dyes in the present with NaCl as a catalyst. The water swellability dramatically decreased and the physical crosslinking led to decreasing of crystallinity of PVA. The lowering of thermal stability was noticed in the physically crosslinked PVA compared to chemically crosslinked PVA due to its lower crosslink density. However even natural dyes have polysaccharides in their chain, their thermal stability was higher than uncrosslinked PVA.

Isolation and Characterization of Microbacterium barkeri LCa and Paenibacillus amylolyticus LCb for PVA [Poiyvinyl Alcohol]Degradation (PVA [Poiyvinyl Alcohol]분해용 균주 Microbacterium barkeri LCa 및 Paenibacillus amylolyticus LCb의 분리 및 특성 연구)

  • 최광근;신종철;전현희;김상용;류원석;이진원
    • KSBB Journal
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    • v.18 no.6
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    • pp.479-484
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    • 2003
  • 34 strains were isolated from dyeing wastewater in order to improve treatment efficiency of dyeing wastewater containing PVA. Two strains of them were finally selected through the PVA degrading test, and identified as Microbacterium barkeri LCa and Paenibacillus amylolyticus LCb. As a result, optimal conditions for microbial growth and PVA degradation were 30$^{\circ}C$, neutral pH, starch as a carbon source, and peptone as a nitrogen source. And it was concluded that these two strains have good ability for PVA degradation. And 90% over PVA was degraded by single culture as well as a mixed culture of 2 different strains.

Effect of PVA Concentration on Strength and Cell Growth Behavior of PVA/gelatin Hydrogels for Wound Dressing

  • Kim, Soyeun;Lim, Hyunju;Kim, Sojeong;Lee, Deuk Yong
    • Journal of Biomedical Engineering Research
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    • v.41 no.1
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    • pp.1-7
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    • 2020
  • Polyvinyl alcohol (PVA)/gelatin hydrogels were prepared by repeating freezing/thawing three times to evaluate the influence of PVA concentration on the strength and the cell growth behavior of the PVA/gelatin hydrogels. The swelling rate of the PVA/gelatin hydrogels decreased with raising the PVA content from 6 wt% to 12 wt% due to the formation of 3-D network inside the hydrogel. No appreciable degradation of the hydrogels was detected. As the PVA content increased from 6 wt% to 12 wt%, the strength of the PVA/gelatin hydrogels increased drastically from 6.4±0.9 kPa to 46.6±9.0 kPa. The PVA/gelatin hydrogels did not show any evidence of causing cell lysis or toxicity, implying that the hydrogels are clinically safe and effective. Although the strength increased with increasing the PVA content, the PVA/gelatin hydrogels containing 8 wt% exhibited the fastest cell growth, which is highly suitable for wound dressing requiring fast healing regeneration.