• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.698-706
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• 2019

Over the last few decades, there have been a lot of efforts to develop soft actuators, which can be external stimuli-responsive and applied to the human body. In order to fabricate medical soft actuators with a dynamic precision control, the 3D crosslinked poly(acrylic acid) (PAAc)/poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) hydrogels were synthesized in this study by using a radiation technique without noxious chemical additives or initiators. After irradiation, all hydrogels showed high gel fraction over 75% and the ATR-FTIR spectra indicated that PAAc/PVA/PEG hydrogels were successfully synthesized. In addition, the gel fraction, equilibrium water content, and compressive strength were measured to determine the change in physical properties of PAAc/PVA/PEG hydrogels according to the irradiation dose and content ratio of constituents. As the irradiation dose and amount of poly(ethylene glycol) diacrylate (PEGDA) increased, the PAAc/PVA/PEG hydrogels showed a high crosslinking density and mechanical strength. It was also confirmed that PAAc/PVA/PEG hydrogels responded to electrical stimulation even at a low voltage of 3 V. The bending behavior of hydrogels under an electric field can be controlled by changing the crosslinking density, ionic group content, applied voltage, and ionic strength of swelling solution.

• Macromolecular Research
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• v.15 no.5
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• pp.459-464
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• 2007

Polymer electrolyte membranes, featuring ionic channels, were prepared from sulfonated dextran/ poly(vinyl alcohol) (sD/PVA) membranes. A stiff sulfated dextran was chosen as the route for ionic transport, since ionic sites are located along the stiff dextran main chain. The sD/PVA blend membranes were annealed and then chemically crosslinked. The characteristics of the crosslinked sD/PVA membranes were investigated to determine their suitability as proton exchange membranes. The proton conductivity was found to increase with increasing amounts of sD inside the membrane, which reached a maximum and then decreased when the sD content exceeded 30 wt%, while the methanol permeability increased with increasing sD content. The good dispersion of sD inside the membrane, which serves as an ionic channels mimic, played a significant role in proton transportation.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.13-16
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• 1998

Poly(vinyl alcohol) (PVA) gels are easily formed via physical pathway. Most PVA solutions including PVA/water solution are well known to form thermally reversible gels at low temperature but these gels showed poor mechanical properties. In order to overcome this weak point, transparent crosslinked PVA hydrogels were prepared by electron beam irradiation or by chemical process with crosslinking agents or additives. (omitted)

• Journal of the Korean Graphic Arts Communication Society
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• v.16 no.3
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• pp.1-13
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• 1998

Some photopolymer, poly(vinyl cinnamoyl acetate)(PVCiA) was synthesized by esterification of polymer(vinyl alcohol(PVA) with monochloroacetic acid, followed by reaction poly(vinyl monochloroacetate)(PVChA) and potassium cinnamate. When esterification of PVA with monochloroacetic acid was reacted in the dimethyl sulfoxide(DMSO), in the synthesis of PVChA, it is very good yield and the successive cinnamoyl acetoxyl esterification of PVCiA can be successfully synthesized. But PVCiA is low photosensitive polymer if not added photosensitizing dyes. Here, we synthesized photosensitizing dyes. trifluoromethylindol squarylium dye derivatives(TFSQ). Indolization of 3-trifluoromethylphenyl-hydrazine formed 4- and 6-substituted indoles, the rate of 4- and 6-substituted indoles is close to unity. Absorption's coefficient of 1,3-bis(4-trifluoromethyl-1,3,3-trimethylindol) squarylium dye(TFSQ) is 7.57$\times$10\ulcorner, PVCiA added with TFSQ(3%) was highly sensitized six times than not added.

• Textile Coloration and Finishing
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• v.20 no.6
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• pp.75-81
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• 2008

This paper dealt with the synthesis and characterization of the polymeric product by the reaction of the water-soluble poly(vinyl alcohol)[PVA] nonwoven fabrics and the phosphoryl chloride ($POCl_3$), which has been applied to prepare water-proofing materials or intermediates for increasing water-proofing or fire-proofing ability of commercially available water-soluble PVA support layer. $POCl_3$ was reacted with PVA nonwoven fabrics under non-aqueous condition, and their reactivity, and chemical structure were checked and discussed. PVA was reacted with $POCl_3$ under the reaction condition of 1:1, or 1:2 mole ratios at 70, 80 and $90^{\circ}C$, and the reaction products were further hydrolyzed. The structure of the resulting products from water soluble PVA nonwoven fabrics reacted with $POCl_3$ were identified by FT-IR or X-ray fluorescence spectrophotometer, and they indicated the PVA polymer chains to have phosphorous and chlorine moieties.

• Textile Coloration and Finishing
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• v.22 no.3
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• pp.229-238
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• 2010

Poly($\varepsilon$-caprolactone) nano/microcapsules(nmcPCL) containing phytoncide oil were synthesized by emulsion diffusion method using ethyl acetate and poly(vinyl alcohol) (PVA) as an organic solvent and an emulsion stabilizer respectively. The influence of the degree of saponofication of the PVA and the weight ratio of core to wall materials was investigated to design nanocapsules in terms of particle size, morphology, and emulsion stability. The encapsulated nmcPCL were characterized by FT-IR spectrometry, particle size analyzer and scanning electron microscope. Mean size of nanocapsules prepared with PVA with a degree of saponofication of 87% was smaller than those of PVA with a degree of saponofication of 98.5% and the mean particle size of the capsules decreased with increasing core/shell ratio.

• Korean Membrane Journal
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• v.11 no.1
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• pp.1-7
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• 2009

This work reports the preparation of proton conductive crosslinked polymer electrolyte membranes by blending poly(vinyl chloride)-g-poly(hydroxyl ethyl acrylate) (PVC-g-PHEA) and poly(vinyl alcohol) (PVA). The PHEA chains of the graft copolymer were crosslinked with PVA using sulfosuccinic acid (SA) via the esterification reaction between -OH of polymer matrix and -COOH of SA. The PVC-g-PHEA graft copolymer was synthesized via atom transfer radical polymerization (ATRP) using direct initiation of the secondary chlorines of PVC backbones. Ion exchange capacity (IEC) continuously increased with increasing concentrations of SA, due to the increasing portion of charged groups in the membrane. However, the water uptake increased up to 20.0 wt% of SA concentration above which it decreased monotonically. The membrane exhibited a maximum proton conductivity of 0.026 S/cm at 20.0 wt% of SA concentration, which is presumably due to competitive effect between the increase of ionic sites and the crosslinking reaction.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.187-190
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• 2002

Poly(vinyl alcohol) (PVA) is a representative hydrophilic and water-soluble polymer and widely employed in various applications such as fibers for clothes and industries, films, membranes, medicines for drug delivery system, and cancer cell-killing embolic materials. Moreover, PVA fibers, gels, and films are potentially high-performance materials because they have high tensile and impact strengths, high tensile modulus, high abrasion resistance, excellent alkali resistance, and oxygen barrier property which are superior to those of any known polymers[1,2]. (omitted)

• Membrane Journal
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• v.15 no.3
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• pp.206-212
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• 2005

Acid-resistant poly(vinyl alcohol) (PVA) membranes connected with ethylene and ether groups were prepared via a thermal crosslinking reaction by varying the ratio of PVA to ethylene glycol diglycidyl ether (EGDE). The crosslinked membranes were characterized using FT-IR and swelling tests, respectively. Pervaporation behaviors with the PVA membranes were investigated for aqueous TFEA (2,2,2-trifluoroethanol) as a function of EGDE content and operating temperature. The pervaporation properties far MA (methacrylic acid)/water mixture were also carried out with the optimized PVA membrane. The PVA membranes prepared with EGDE showed more excellent acid-resistance than those crosslinked with gluaraldehyde. The membranes showed high permeation fluxes of 0.1 and $0.3\;km^2h$ and high separation factors of 100 and 900 in the $96\;wt\%$ TFEA and MA aqueous fred mixtures at high temperature above $80^{\circ}C$, respectively. These confirmed theses membranes could be used in esterification membrane reactor process for the production of 2,2,2-trifluoroethylmetacrylate (TFEMA).

• Polymer(Korea)
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• v.34 no.5
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• pp.415-423
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• 2010

Poly(vinyl alcohol)(PVA) with high degree of hydrolysis of above 98% was dissolved in dimethyl sulfoxide(DMSO), and the shear viscosity was measured up to $C{\simeq}0.14\;g/mL$ in the semi-dilute solution regime. Next, as probe particle, polystyrene(PS) latex was introduced into this matrix system and its delayed diffusion due to polymer concentration was investigated by means of dynamic light scattering. When the solution viscosity of PVA/DMSO was plotted against the reduced concentration $C[{\eta}]$, which is scaled by the intrinsic viscosity, the molecular weight dependence was strongly appeared at C$[{\eta}]$ >2. Some heterogeneties in polymer solution were considered as its source. Contrary, the diffusion of probe particle in the matrix solution was observed as a single mode motion at whole concentration range but its ratio of its diffusion coefficient at solution to that at solvent, D/Do did not show any molecular weight dependence at all. However, the application limit of the stretched exponential function was disclosed at C$[{\eta}]$ >2.5.