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Li, Guang-Hua,Cho, Chang-Gi The Polymer Society of Korea 2002 Macromolecular Research Vol.10 No.6
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.
Payam Zahedi,Iraj Rezaeian,Seyed Hassan Jafari,Zeinab Karami 한국고분자학회 2013 Macromolecular Research Vol.21 No.6
The main purpose of this work was to develop biomedical electrospun nanofibrous mats based on a poly(vinyl alcohol)/poly(ε-caprolactone) (80/20) hybrid with a defined drug release rate using tetracycline hydrochloride as a model drug. The electrospinning process parameters, such as polymer solution concentration, distance between injecting syringe tip/collector, voltage, injected flow rate and the polyvinyl alcohol crosslinking time were optimized via a D-optimal design method for a suitable nanofiber diameter with an optimal drug release rate. The morphology of nanofibers and their mean diameters were studied by a scanning electron microscopy technique. The results showed that the mean diameters of nanofibers were significantly reduced after drug loading. The swelling,weight loss and biodegradability of nanofibers samples investigated by FTIR were also determined. Two main mechanisms via penetration and erosion were evaluated. In vitro drug release in a phosphate buffer environment at pH=7.2for the samples demonstrated that the polymer type and hydrophilic nature of the polymer/drug system is very effective in the kinetics and mechanism of drug release. Hybridization of poly(vinyl alcohol)/poly(ε-caprolactone) with a known ratio showed to be a suitable and useful method in the electrospinning of nanofibers samples for superior control of the drug release rate. Finally, nanofibrous mats of polyvinyl alcohol and polyvinyl alcohol/poly(ε-caprolactone)hybrid (80/20) had much better drug release rate characteristics for tetracycline hydrochloride as a model drug compared with cast film samples loaded with the same drug.
Characterization of Poly(vinyl phosphate-b-styrene) by Solid-State $^{31}P$ NMR and Titration
Li, Guang-Hua,Kim, Sang-Hun,Cho, Chang-Gi,Park, Tae-Joon,Kim, Yong-Ae The Polymer Society of Korea 2006 Macromolecular Research Vol.14 No.5
Poly(vinyl phosphate-b-styrene) (PVPP-b-PS) block copolymers were synthesized successfully from poly(vinyl alcohol-b-styrene) (PVA-b-PS) by reaction with phosphorus oxychloride and subsequent hydrolysis. The obtained block copolymers were slightly crosslinked, and were characterized by various analytical techniques. The total phosphorus content and the ratio of the differently bound phosphorus were obtained by both solid-state $^{31}P$ NMR and pH titration, but the results differed slightly. Characterization by energy dispersion X-ray analysis (EDS) or Rutherford back scattering (RBS), on the other hand, determined the total phosphorus contents, but the results were quite different from those by solid-state $^{31}P$ NMR.
셀룰로스 나노크리스탈 복합화에 의한 Poly(vinyl alcohol-co-ethylene) 필름의 기체차단성 향상 효과
안홍주,최준호,조세연,곽효원,진형준 한국섬유공학회 2017 한국섬유공학회지 Vol.54 No.6
Barrier properties of packaging materials can be enhanced by controlling their microstructure and/or blending them with nanofillers such as cellulose nanocrystals (CNCs). CNCs have attracted considerable attention for use in reinforcing composite materials because of their exceptionally high specific strength and modulus, low density, chemical tunability, renewable nature, and relatively low cost. In this study, barrier films were prepared by incorporating CNCs into a poly(vinyl alcohol-co-ethylene) (EVOH) matrix. The CNCs prepared by acid hydrolysis of microcrystalline cellulose were ~348 nm long and 20 nm in diameter, with aspect ratios of 16. The nanocomposites were prepared by incorporating 1, 2, and 3 wt.% CNCs into an EVOH matrix using solution casting. Turbiscan analysis and contact angle measurements show that the EVOH/CNC composite films possessed interfacial interactions and good dispersion properties. As a result, these composite films may not show any decrease in their transparency. In particular, the oxygen transmission rate in the composite films significantly decreased from 3.2 cm3/(m2·day) to 1.3 cm3/ (m2·day) when the CNC was added, indicating that the EVOH/CNC nanocomposite films can be used as barrier packaging materials.
Fatma Kurs¸ un,Nuran Is¸ ıklan 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.41 No.-
This study aims to develop thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm) graftedpoly(vinyl alcohol) (PVA-g-PNIPAAm) copolymer membranes for separation of isopropyl alcohol(IPA)/water mixtures via pervaporation. PVA-g-PNIPAAm copolymers were synthesized by microwavesupportedgraft copolymerization. Structure of copolymers was characterized by element analysis, FTIR,TGA/DTG/DSC, 13C NMR and SEC. PVA-g-PNIPAAm membranes prepared with casting technique werecharacterized by SEM-AFM. Effects of grafting yield, operation temperature, and feed concentration onseparation factor and flux were investigated to determine the membrane performance. The maximumseparation factor was 95 with flux of 0.011 kg/m2 h at 87.4% IPA. Thermo-responsive PVA-g-PNIPAAmmembranes developed in this study are promising for pervaporation.
최선호,홍상은,윤국로 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Hydrogel for biomaterials need to good mechanical property like a tissue. But, usually natural hydrogels have a low mechanical property. Therefore, biocompatible polymer based double-network (DN) hydrogel with high toughness and biocompatibility have been good application as biomaterials. In this study, we synthesized a double crosslinking alginate/poly (vinyl alcohol-co-acrylamide) through a two-step process. First network, sodium alginate (SA) as grafted to the dopamine (DA) and then add to natural extracts. Second network, P(VA-AM) was conjugation with first network by schiff base reaction. Also, crosslinking agents used ammonium persulfate, and N,N'-methylenebis-acrylamide to form SA-DA/P(VA-AM) DN hydrogel. Finally, the chemicophysical properties of the DN hydrogel was confirmed by mechanical properties, swelling ratio, Field-Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FT-IR), MTT assay, Thermogravimetric Analysis (TGA).
Titilope John Jayeoye,Ozioma Forstinus Nwabor,Thitima Rujiralai 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.89 No.-
A highly stable and dispersed aqueous nanocomposite of silver nanoparticles/poly(vinyl alcohol-coethyleneglycol)/poly(3-aminophenyl boronic acid) (Ag/(PVA-PEG)/PABA) was synthesized. PVA and PEGwas blended at the optimum volume ratio of 16:4 to obtain poly(vinyl alcohol-co-ethylene glycol)(PVA-PEG) blend. 3-Aminophenyl boronic acid served as the reductant of silver nitrate and was in situoxidatively polymerized to obtain poly(3-aminophenyl boronic acid) (PABA). Subsequently, (PVA-PEG)blend served as matrix for PABA polymerization. The polymer blend helped to improve PABA solubility byproviding platform for PABA anchoring, through covalent bonding with the free hydroxyl groups of theblend. Additionally, PABA is a highly conducting polymer, hence the synthesized nanocompositedemonstrated improved conductivity. The maximum absorption peak of Ag/(PVA-PEG)/PABA was at422 nm, with particle sizes between 10 and 15 nm and zeta potential value of 25.8 mV. FESEM showedspherical AgNPs sprinkled on the surface of the nanocomposite while 40% Ag was presented in EDXresult. The Ag/(PVA-PEG)/PABA exhibited good antibacterial potency against Bacillus cereus andEscherichia coli where the ruptured bacterial cell was observed on FESEM. Importantly, it showed reliablebiocompatibility without imparting deleterious red blood cell hemolysis and non-cytotoxic to normalhuman cell line. Overall, these results emphasized the exciting biomedical potentials of Ag/(PVA-PEG)/PABA nanocomposite.
Rikarani R. Choudhury,Jaydevsinh M. Gohil 한국고분자학회 2022 폴리머 Vol.46 No.5
Development of proton conducting membrane electrolyte is one of the most important research area within thedomain of direct methanol fuel cells (DMFCs). This study reports the preparation of glutaraldehyde-crosslinkedpoly(vinyl alcohol-co-styrenesulfonic acid) proton exchange membrane (PEM) for DMFC. In order to understand theeffect of the extent of crosslinking on the PEM properties, varying concentration of glutaraldehyde was used. Key properties of PEMs such as water uptake, swelling behavior, ion-exchange capacity, proton conductivity, and methanol permeability were thoroughly analyzed. PEM formed using 0.5 M glutaraldehyde solution resulted in a crosslinked PEMwith the moderate properties, such as swelling, water uptake, proton conductivity and mechanical strength, along withthe exhibition of high proton conductivity and lower methanol permeability compared to commercial Nafion-117. In addition, optimized PEM produced a peak power density of 58 W/m2at a current density of 300 A/m2, when DMFC fed with2 M methanol solution at 60 °C.