• Macromolecular Research
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• v.15 no.1
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• pp.22-30
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• 2007

High water vapor permeable coating materials were prepared by blending aqueous poly(vinyl alcohol) (PVA) solution with waterborne polyurethane-urea (WBPU) dispersions synthesized by prepolymer mixing process. Stable WBPU/PVA dispersions were achieved at PVA content below 30 wt%. As the water soluble polymer PVA content increased, the number and density of total micro-pores (tunnel-like/isolated micro-pores) formed after the dissolution of PVA in water increased, and the water vapor permeability of coated Nylon fabric also increased significantly. Using WBPU/water soluble polymer PVA blends as a coating material and then dissolving PVA in water was confirmed to be an effective method to obtain prominent breathable fabrics.

• Korea-Australia Rheology Journal
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• v.19 no.2
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• pp.81-88
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• 2007

Blends of collagen dispersion (COL) with poly(vinyl alcohol) (PVA) in different weight ratios were investigated by oscillatory rheometry, Fourier transform-infrared spectroscopy and scanning electron microscopy. It was found that even with 80% of PVA, the COL/PVA blends behaved more like collagen dispersion than pure PVA solution in the dynamic thermal and frequency processing, for instance, a dominant elastic appearance (G'>G"), a similar shear thinning behavior and the thermal denaturation below $40^{\circ}C$. However, influence on the blend behaviour by PVA was noticeable, for instance, an increase of dynamic denaturation temperature, the decreasing intensity of amide I, II and III bands as well as the diminishing irregular pores on the surface of blends. The interaction between collagen and PVA could be observed, especially at the regions with low content or high content of PVA.

• Carbon letters
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• v.15 no.4
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• pp.282-289
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• 2014

Blends of poly(vinyl alcohol) (PVA), polyethyleneimine (PEI), and graphene oxide (GO) were prepared by solution casting method. Calorimetric thermal properties of the blends were investigated. The $T_gs$ of PVA/PEI blends were higher than the $T_gs$ of either of the component polymers at low concentrations of PEI. These abnormal increases of $T_gs$ may be due to the negative entropy of mixing which is associated with strong hydrogen bonding between PVA and PEI. The degree of depression of $T^0_ms$ was not reduced by the negative entropy of mixing, since strong hydrogen bonding also causes an increase in the magnitude of negative ${\chi}$ between PVA and PEI. The $T_g$ of PVA was increased significantly by adding 0.7 wt.% GO into PVA. The magnitude of negative ${\chi}$ was increased by adding GO into the blends of PVA and PEI.

• Journal of the Korean institute of surface engineering
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• v.42 no.2
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• pp.59-62
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• 2009

Antireflection pattern, moth-eye structure, was fabricated on lens using Ultra Violet nanoimprint lithography and flexible template. Ni template with conical shaped structure was used as a master template to molding. The flexible poly vinyl alcohol template was fabricated by molding. This poly vinyl alcohol template was used as an imprint template of imprint at lens. Using Ultra Violet nanoimprint lithography and poly vinyl alcohol template, polymer based moth-eye structure was formed on lens and its transmittance was increased up to 94% from 92% at 550 nm wavelength.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.33-36
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• 2002

폴리비닐알코올 (poly(vinyl alcohol), PVA)은 의류 및 산업용 섬유, 막, 약물전달, 암세포 괴사용 색전제등에 널리 사용되고 있다[1,2]. 이런 PVA와 같은 비닐계 고분자는 분자량 이외에도 입체규칙성에 따라 그 물리적 성질이 변화하는데 그 입체규칙성에 따라 혼성배열, 동일배열 및 교대배열 고분자로 분류할 수 있다. PVA는 일반적으로 55% 이상의 교대배열 다이애드기 함량을 가질 때 교대배열 PVA라고 불린다. (중략)

• Membrane Journal
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• v.26 no.1
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• pp.32-37
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• 2016

The poly(vinyl alcohol) $(PVA)/AgCF_3SO_3/Al(NO_3)_3$ electrolyte membrane was fabricated to prepare for highly permeable facilitated olefin transport membrane, compared with poly(vinylpyrrolidone) $(PVP)/AgCF_3SO_3/Al(NO_3)_3$ complex. In order to examine the characteristics of $PVA/AgCF_3SO_3/Al(NO_3)_3$ membrane, we used the analytical methods such as SEM, FT-IR, and FT-Raman. The best separation performance was observed at the mole ratio of 1 : 1 : 0.01 $PVA/AgCF_3SO_3/Al(NO_3)_3$ among various $Al(NO_3)_3$ concentration. As a result, the selectivity was 12 and mixed-gas permeability was 3.5 Barrer. Furthermore, the selectivity and permeability remained constant for up to 115 h.

• Membrane Journal
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• v.12 no.4
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• pp.255-261
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• 2002

Poly(vinyl alcohol) (PVA) membranes crosslinked with poly(acrylic acid-co-maleic anhydride) (PAM) as a polymeric crosslinking agent were prepared to investigate the pervaporation performance for the dehydration separation of aqueous ethanol solution. The characteristics of the resulting membranes crosslinked(x) were analysed by FT-IR and water swelling test. The water swelling decreased with increasing crosslinking agent content. The crosslinked PVA membranes with PAM showed lower water swelling than those of PVA membrane crosslinked with glutaraldehyde and modified PVA membrane. The swelling of water molecules in the crosslinked PVA membranes is more restricted by both chemical crosslinking between PVA and polymeric crosslinking agent chains and physical crosslinking by the entanglement between the PVA and polymeric crosslinking agent chains. For the pervaporation of aqueous ethanol solution through the crosslinked membrane, as the contents of crosslinking agent increased, the separation factor increased while the permeation flux decreased. The separation factor slightly decreased and permeation flux increased with increasing feed water content. As a result it could be considered that PVA-PAM membranes suppressed the plasticization effect even in the range of high water concentration in fled.

• Membrane Journal
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• v.25 no.4
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• pp.327-331
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• 2015

Poly(vinyl alcohol) (PVA) membranes cross-linked with sulfosuccinic acid (SSA) in which poly(4-styrene sulfonic acid-co-maleic acid) (PSSA_MA) was blended to endow more ion exchange capacity were prepared to measure the permselectivities of water-alcohol mixtures by pervaporation separation technique. The feed mixtures of binary aqueous methanol, ethanol and iso-propyl alcohol solution by 90 wt% alcohol portion were used. Typically, for PVA10/SSA9/PSSA_MA90 membrane, the flux of 202.6, 47.8, $20.2g/m^2hr$ for aqueous methanol, ethanol and iso-propyl alcohol solutions was shown while the best separation factors of 34.2, 291 and 991 were given by PVA10/SSA11/PSSA_MA80 membrane. More details are discussed in main text of this article.

• Fibers and Polymers
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• v.7 no.3
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• pp.229-234
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• 2006

Poly(vinyl acetate) (PVAc)/poly(vinyl alcohol) (PVA)/montmorillonite (MMT) clay nanocomposite microspheres with a core/shell structure have been developed via a suspension polymerization approach. In order to prepare the PVAc/ MMT and PVAc/PVA/MMT nanocomposite microspheres, which are promising precursor of PVA/MMT nanocomposite microspheres, suspension polymerization of vinyl acetate with organophilic MMT and heterogeneous saponification were conducted. A quaternary ammonium salt, cetyltrimethylammonium bromide, was mixed with the MMT in the monomer phase prior to the suspension polymerization. The rate of conversion decreased with an increase in MMT concentration. The incorporation of MMT into the PVAc was verified by FT-IR spectroscopy. Organic vinyl acetate monomers were intercalated into the interlayer regions of organophilic clay hosts and followed by suspension polymerization. Partially saponified PVA/MMT nanocomposite microspheres with a core/shell structure were successfully prepared by heterogeneous saponification.

• Polymer(Korea)
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• v.38 no.3
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• pp.378-385
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• 2014

Multiwall carbon nanotubes (MWCNTs) were modified with a water soluble polymer, poly(vinyl alcohol), PVA, using a simple ultrasonic wave in water. Under the irradiation of ultrasound, PVA chains were severed as macroradicals and instantly grafted onto the surface of MWCNTs due to the radical scavenging effect of MWCNTs. To control the grafting PVA onto MWCNTs, the ultrasonication power and irradiation time were changed from 300 to 500 W and from 10 to 50 min, respectively. The grafted PVA onto MWCNTs was confirmed by FTIR, TGA, SEM, and TEM. Dispersion stability of the modified MWCNTs was monitored by Turbiscan. The amount of grafted PVA on MWCNTs increased with the increase in the sonication power and irradiation time. The grafted PVA on MWCNTs induced the improved dispersion stability of the modified MWCNTs in water. These findings exhibit that ultrasound can be readily used for the grafting polymer chains on MWCNTs.