• 폴리머
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• 제31권5호
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• pp.385-392
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• 2007

Poly (N-vinylpyrrolidone) (PVP) groups were grafted onto a poly(3-hydroxybutyrate-co-3-hydroryvalerate) (PHBV) backbone in order to modify its properties and synthesize a novel biocompatible copolymer. The crystallization behavior of PHBV and grafted PHBV was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). During the cooling-induced crystallization process, the crystallization temperature and the crystallization rate of the grafted PHBV decreased with increasing PVP weight fraction. On the heating scans of all grafted PHBV samples, a new crystallization exothermic peak appeared at almost the same temperature, suggesting the operation of a recrystallization process, while the melting temperature ($T_m$) and the apparent enthalpy of fusion (${\Delta}H_f$) were not affected by graft modification. During the isothermal crystallization process at the same temperature, the presence of side PVP groups decreased the spherulitic growth rate and the spherulitic band spacing with increasing PVP weight fraction in samples.

• 폴리머
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• 제26권6호
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• pp.792-802
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• 2002

본 연구에서는, 방사선($^{60}$Co ${\gamma}$-rays) 가교를 이용하여 poly(vinyl alcohol)(PVA)/poly(N-vinylpyrrolidone)(PYP)/글리세린/키토산의 혼합물로부터 하이드로겔을 제조하였다 하이드로겔이 상처 치료용 드레싱으로 사용될 수 있는지 예측하기 위해 겔화율, 팽윤도, 겔강도 같은 기계적 성질을 측정하였다. PVV와 PVP의 조성비는 6 : 4, 키토산은 0.3 wt%, 글리세린은 0~5 wt%, PVA/PVP/글리세린/키토산 수용액의 고형분의 농도는 15 wt%이었다. 하이드로겔의 기계적 성질에 조사선량이 미치는 영향을 예측하기 위해 PVA/PVP/글리세린/키토산 혼합물에 25~60 kGy의 감마선을 조사하였다. 겔화율과 겔강도는 글리세린 조성비가 작을수록 조사선량이 커질수록 증가하였다. 팽윤도는 글리세린 조성비가 클수록, 조사선량이 작을수록 증가하였다. PVA/PVP/글리세린/키토산 하이드로겔에서 글리세린은 겔 모양의 변형을 막는다. 제조된 하이드로겔이 상업용 바셀린 거즈보다 치료 효과가 우수하였다.

• Transactions on Electrical and Electronic Materials
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• 제12권5호
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• pp.222-225
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• 2011

Lead zirconate titanate (PZT) films were fabricated on Pt/Ti/$SiO_2$/Si substrate by the sol-gel method using a sol containing poly(N-vinylpyrrolidone) (PVP). PVP in alkoxide solutions can suppress the condensation reaction in gel films during heat treatment, and increase the viscosity of alkoxide solutions. Single-phase PZT films as thick as 1 ${\mu}m$ were deposited by repetitive coating with successive third-step heat treatments at 150$^{\circ}C$, 350$^{\circ}C$ and 650$^{\circ}C$. After heat treatment, the films were crack free, and optically transparent. As a result, we demonstrated a PZT film with a PVP molar ratio of 0.5, which has a permittivity of 734, a dielectric loss of 0.042, a $P_r$ of 40.5 ${\mu}C/cm^2$ and an $E_c$ of 156 kV/cm.

• 대한의용생체공학회:의공학회지
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• 제9권1호
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• pp.67-72
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• 1988

Poly (HPMA/NVP) hydrogel was synthesized according to the composition and the con- centration of the crosslinking agent. The swelling degree of the P(HPMA/NVP) hydrogel decreased with increasing of P(HPMA) composition and crosslinking agent. The glass transi- tion and softening temperatures of the P(HPMA/NVP) increased with increasing of P(HPMA) composition. The composition of P(HPMA/NVP) : 70/30 and the concentration of the crosslin- king agent of 0.5 wt % gave the optimum condition in the application to the contact lens. There were also adequate in the mechanical, refractive properties and in vivo test in the P(HPMA/ NVP): 70/30 system.

• Advances in environmental research
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• 제3권2호
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• pp.107-116
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• 2014

This study aimed to synthesize dispersed and reactive nanoscale zero-valent iron (nZVI) with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), nontoxic and biodegradable stabilizer. The nZVI used for the experiments was prepared by reduction of ferric solution in the presence of PVP/VA with specific weight ratios to iron contents. Colloidal stability was investigated based on the rate of sedimentation, hydrodynamic radius and zeta potential measurement. The characteristic time, which demonstrated dispersivity of particles resisting aggregation, increased from 21.2 min (bare nZVI) to 97.8 min with increasing amount of PVP/VA (the ratios of 2). For the most stable nZVI coated by PVP/VA, its reactivity was examined by nitrate reduction in a closed batch system. The pseudo-first-order kinetic rate constants for the nitrate reduction by the nanoparticles with PVP/VA ratios of 0 and 2 were 0.1633 and $0.1395min^{-1}$ respectively. A nitrogen mass balance, established by quantitative analysis of aqueous nitrogen species, showed that the addition of PVP/VA to nZVI can change the reduction capacity of the nanoparticles.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1993년도 ACT 93
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• pp.841-845
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• 1993

• 폴리머
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• 제25권2호
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• pp.270-278
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• 2001

의료용 고분자로 널리 알려진 poly(vinylalcohol)(PVA)와 poly(N-vinylpyrrolidone)(PVP)를 이용하여 상처치료용 하이드로겔을 제조하였다. PVP 하이드로겔의 기계적 강도를 향상시키기 위해 PVA/PVP 혼합용액에 \"freezing and thawing (동결융해)\"을 반복한 후 방사선 ($^{60}$Co${\gamma}$-rays)을 조사하여 하이드로겔을 얻었다. PVA와 PVP의 조성비 (30 : 70 ~ 100 : 0), 동결융해의 반복횟수, PVA 분자량을 변화시키면서 PVA/PVP 하이드로겔의 겔화율, 팽윤도, 겔강도를 측정하였다. PVA/PVP 하이드로겔은 방사선 조사로만 제조되었을 때 보다 동결융해 반복 후 방사선조사했을 때 겔화율과 겔강도가 향상되었다. 이외에 동결융해의 반복정도에 따른 물성의 특징을 논의하였다.특징을 논의하였다.

• 공업화학
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• 제24권4호
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• pp.416-422
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• 2013

알지네이트에 은이온을 첨가하기 위하여, 질산은 수용액을 이용하여 은-알지네이트를 제조하였다. 본 연구에서는 은-알지네이트를 Poly vinylpyrrolidone (PVP) 수용액과 블렌드하였고, 전기방사는 블렌드 용액을 이용하여 수행하였다. 은-알지네이트/PVP 혼합 용액의 항균효과는 colony counting test로 대장균과 포도상 구균에 대해 확인하였다. 은-알지네이트/PVP 혼합용액의 전기방사 조건은 조성물의 농도를 다양하게 하여 방사거리 22 cm, 방사속도 0.01 mL/min, 전압 26 kV 조건하에서 수행하여 나노섬유를 제조하였다. 은-알지네이트 나노 섬유의 형태와 크기는 SEM과 Image J를 통해 확인하였으며, 전기방사된 SA5P15 섬유들의 평균 직경은 124 nm를 보였으며, 균일하게 방사되는 것을 확인하였다. SA5P15의 균 감소율은 24 시간 후 99.9%를 보였다.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1869-1874
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• 2010

By reducing PVP with $H_2NOH$.HCl and NaOH 2:2:1 mass ratios in aqueous ethanol, poly-N-vinyl pyrrolidone oxime [PVPO] was prepared with 92% yield. Applying the sol-gel concept, orthosilicic acid [OSA] was made by hydrolyzing TEOS with ethanol in 1:0.5 molar ratios using 1 N KOH aqueous solution as a catalyst. The OSA + PVPO + $_L$-Valine ($\alpha$-amino acid) were mixed with pure ethanolic medium in 1:2:2 mass ratios and refluxed at $78^{\circ}C$ and 6 pH for 6.5 h. A white residue of poly-N-vinyl pyrrolidone oximo-L-valyl-siliconate [POVS] appeared after 5 h. The heating of reaction mixture was stopped and the contents were brought to NTP. The residue formation of POVS was intensified with lowering a temperature and completely solidified within 5 h, was filtered using a vacuum pump with Whatmann filter paper no. 42. The residue of POVS was washed several times with 20% aqueous cold ethanolic solution and dried in vacuum chamber at $25^{\circ}C$ for 24 h. The MP was noted above $350^{\circ}C$. Structural and internal morphology were analyzed with IR and $^1H$-NMR, and SEM respectively. A drug loading and transporting ability of the POVS in water and at pH = 5 and 8 was determined chromatographically.

• Macromolecular Research
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• 제10권2호
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• pp.115-121
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• 2002

Synthesis of polymers with controlled thermosensitive properties was carried out by conventional radical copolymerization of N-isopropylacrylamide (NIPAAm) with N-vinylpyrrolidone (NVP) taken as a hydrophilic comonomer. Lower activity of NVP rather than NIPAAm was revealed by gravimetric and $^1$H NMR analysis. Thermosensitive properties of the copolymers were investigated. It was found that aqueous solutions of the copolymers undergo thermo-induced phase transition and become opaque, precipitate or gel with heating. After formation of the gels their significant contraction was observed at storage. Swelling degree and amount of expelled water were measured in dependence on the copolymer composition, temperature and ionic strength of environment medium and concentration of the solution. It was determined that in collapsed state gels exhibit quite high water content. According to physico-chemical properties of the copolymers observed they could be suitable for biomedical application as an injectable implant material.