• Title/Summary/Keyword: Poly(vinylpyrrolidone)

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Preparation and Crystallization Behavior of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Grafted with Poly(N-vinylpyrrolidone) (Poly(N-vinylpyrrolidone)이 그래프트된 Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) 공중합체의 합성 및 결정화 거동)

  • Wang, Wei;Zhang, Yu;Chen, Yanmo
    • Polymer(Korea)
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    • v.31 no.5
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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.

Interaction between Poly(vinylpyrrolidone) and Ionic Dyes in Aqueous Solution System (I)

  • Lee, Sangchul;Kim, Heain;Park, Soomin
    • Textile Coloration and Finishing
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    • v.24 no.4
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    • pp.239-246
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    • 2012
  • The binding isotherms of ionic dyes with Poly(vinylpyrrolidone) in aqueous solution were determined by the dynamic dialysis technique. The shape of the isotherms of cationic dye, C. I. Basic Red 18 with poly(vinlypyrrolidone) showed a partition type. It suggests that the binding involves a non-cooperative mode. Isotherms of an anion dye, a synthesized dye by coupling of diazotized m-trifluoromethylaniline with 2-naphthol-6-sulfonic acid, were sigmoid type and showed multimode interaction. The results were interpreted by the McGhee von Hippel theory. The thermodynamic parameters for the complex formation of the dyes-polymer were calculated from their temperature dependences of the intrinsic binding constant.

Preparation and Characterization of Poly(vinyl alcohol)/Poly(N-vinylpyrrolidone)/Glycerin/Chitosan Hydrogels by Radiation (방사선 가교에 의해 제조된 Poly(vinyl alcohol)/Poly(N-vinylpyrrolidone)/글리세린/키토산 하이드로겔의 제조 및 특성)

  • 박경란;노영창
    • Polymer(Korea)
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    • v.26 no.6
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    • pp.792-802
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    • 2002
  • In this study, hydrogels from mixtures of poly (vinyl alcohol) (PVA)/poly(N-vinylpyrrolidone) (PVP)/glycerin/chitosan were prepared by γ-ray irradiation and the mechanical properties such as gelation, water absorptivity, and gel strength were examined to evaluate the applicability of these for wound dressing. Then PVA:PVP was weight ratio of 6 : 4, the concentration of chitosan was 0.3 wt%, the concentration of glycerin was in the range of 0∼5 wt%t. The solid concentration of PVA/PVP/glycerin/chitosan solution was 15 wt%. Gamma irradiation doses of 25, 35, 50, and 60 kGy were exposed to a mixture of PVA/PVP/glycerin/chitosan to evaluate the effect of irradiation dose. Gel content and gel strength increased as glycerin concentration in PVA/PVP/glycerin/chitosan decreased, and as irradiation dose increased. Swelling degree increased as glycerin concentration in PVA/PVP/glycerin/chitosan increased, and as irradiation dose decreased. The glycerin in PVA/PVP/glycerini/chitosan hydrogel prevented the transformation of shape. These hydrogel dressings had better curing effect than vaseline gauge.

Fabrication of 1 ㎛ Thickness Lead Zirconium Titanate Films Using Poly(N-vinylpyrrolidone) Added Sol-gel Method

  • Oh, Seung-Min;Kang, Min-Gyu;Do, Young-Ho;Kang, Chong-Yun;Yoon, Seok-Jin;Nahm, Sahn
    • Transactions on Electrical and Electronic Materials
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    • v.12 no.5
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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.

Synthesis of Poly(hydroxypropyl methacrylate-co-N-vinylpyrrolidone) hydrogel and its Application to the Contact Lens (Poly(hydroxypropyl methacrylate-co-N-vinylpyrrolidone) hydrogel의 합성과 콘텍트렌즈에의 응용)

  • 조종수
    • Journal of Biomedical Engineering Research
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    • v.9 no.1
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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.

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Miscibility of Polysulfone/Poly(1-vinylpyrrolidone-co-styrene) Blends and Their Application to the Ultrafiltration Membrane

  • Kim, Joo-Heun;Yoo, Jung-Eun;Kim, Chang-Keun
    • Macromolecular Research
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    • v.10 no.4
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    • pp.209-214
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    • 2002
  • Miscibility of polysulfone (PSf) with various hydrophilic copolymers was explored. Among these blends, PSf gives homogeneous mixtures with poly(1-vinylpyrrolidone-co-styrene) copolymers [P(VP-S)] when these copolymers contained VP from 68 to 88 wt%. Microporous membranes for the ultrafiltration process were prepared from PSf blends with P(VP-S) copolymers. The membranes prepared from the PSf/(VP-S) blends exhibited higher water flux than the membranes prepared from PSf irrespective of the VP content. The solute rejection examined with the membranes fabricated from the miscible blends was similar to that of PSf membrane. However, the solute rejection examined with the membranes fabricated from the immiscible blends was lower than that of PSf membranes.

Synthesis of PVA/PVP Hydrogel by Irradiation Crosslinking (방사선 가교에 의한 PVA/PVP 하이드로겔 제조 및 드레싱에의 응용)

  • 김태훈;노영창
    • Polymer(Korea)
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    • v.25 no.2
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    • pp.270-278
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    • 2001
  • Hydrogels for wound dressing were manufactured using poly(vinylalcohol)(PVA) and poly(N-vinylpyrrolidone)(PVP). The hydrogels were obtained by exposing to $^{60}$ Co${\gamma}$-rays after freezing and thawing of aqueous solutions of PVA and PVP to improve mechanical strength. Mechanical properties such as gelation, water absorptivity and gel strength were examined after repeating the \"freezing and thawing\" of PVA/PVP hydrogels, and then irradiating them at 40 kGy. The PVA/PVP ratio was in the range of 30:70 ~ 100:0, and the solid concentration of PVA/PVP was 20 wt%. The gelation and strength of hydrogels were much higher when \"freezing and thawing\" and the irradiation process were used than when only the irradiation process was utilized. In addition, the mechanical properties of PVA/PVP hydrogels after repetition of \"freezing and thawing\" are discussed. thawing\" are discussed.ssed.

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Antibacterial Properties of Silver-alginate/PVP Nanofiber (은-알지네이트/PVP 나노섬유의 항균 특성)

  • Choi, Yoo-Sung;Min, Kyung-Du;Yoon, Doo-Soo
    • Applied Chemistry for Engineering
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    • v.24 no.4
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    • pp.416-422
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    • 2013
  • In order to incorporate silver ions into the alginate, silver-alginate was prepared with aqueous solutions of silver nitrate. In the study, the silver-alginate was prepared by blending with poly vinylpyrrolidone solutions and the electrospinning was performed by using this blend solution. Antibacterial properties of silver-alginate/PVP solutions were estimated for Escherichia coli and Staphylococcus aureus by the colony counting test. Electrospinning conditions of silver-alginate/PVP solution were the tip-to-collector distance of 22 cm, the flow rate of the solution at 0.01 mL/min, and the voltage at 26 kV. The form and size of silver-alginate/PVP nanofibers were estimated by SEM and Image J. The average diameter of the electrospun SA5P15 fibers was 124 nm and showed a narrow diameter distribution. The reduction of bacteria for SA5P15 exhibited 99.9% after 24 h.