• Elastomers and Composites
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• v.50 no.4
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• pp.286-291
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• 2015

Polyvinylacetate (PVAc) was prepared using thermal initiation and redox initiation via emulsion polymerization at $80^{\circ}C$. The polymerization conditions had a significant effect on the properties of the synthesized PVAc. When hydrogen peroxide and tartaric acid as the initiator for redox polymerization were used, the synthesized PVAc had a low molecular weight. In comparison with thermal polymerization, smaller PVAc particles were formed during the redox polymerization due to relatively faster polymerization rate, which in turn resulted in improved adhesion property. It is considered that the rapid generation of smaller particles induces the formation of a large surface area.

• Macromolecular Research
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• v.11 no.1
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• pp.36-41
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• 2003

Holographic gratings in two kinds of photopolymers (PPs) were fabricated by optical interference method. Polyvinylalcohol (PVA) and polyvinylacetate (PVAc) were employed as polymer binders and photopolymerization of acrylamide (AA) was confirmed using infrared spectroscopy. Dynamic behavior of the diffraction efficiency was monitored and its temporal stability at room temperature was also observed. Additionally, the temperature dependence of these gratings was investigated in two PPs. The surface topographical change of the photopolymer layer was observed by atomic force microscope (AFM).

• Proceedings of the Korean Vacuum Society Conference
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• 2004.02a
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• pp.99-99
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• 2004

• Polymer(Korea)
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• v.25 no.1
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• pp.78-89
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• 2001

Morphological changes of unsaturated polyester/polyvinylacetate semi-IPN were studied while the phase separation and the cure reaction occurred in a competing fashion. The light scattering and thermal analysis techniques were used to investigate the phase separation rates and mechanical properties resultantly induced by molecular diffusion of thermoplastic polymer during the curing process of thermosetting polymer. The reaction activation energy was calculated by using Flynn-Wall method and the semi-IPN structure exhibited various phase-separation morphological characteristics. When PVAc composition was 10 wt%, the phase separation was not observed during the curing reaction, but the phase separation occurred in a similar fashion to nucleation and growth(NG) mechanism at room temperature. On the other hand, when PVAc composition was over 11.65 wt%, the phase separation was generated in the middle of the curing process. Consequently, the phase separation seemed to influence the curing reaction rate, which was also supported by the changing activation energy with conversion and PVAc composition. Finally, the total scattered intensity was measured at various temperature, and subsequently the diffusion rates of phase separation R(${\beta}m$) were evaluated.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.25-25
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• 2012

농업용 비닐하우스에 사용되는 EVA (ethylene-vinylacetate copolymer)고분자 필름의 무적성을 향상시킬 목적으로 EVA 및 PVAc (polyvinylacetate)필름을 가성소다 용액으로 가수분해하여 친수성을 검토하였다. EVA는 분말상의 고분자를 프레스로 압착하여 필름으로 성형하였으며, PVAc는 아세톤에 용해한 후에 필름으로 성형하였다. 가수분해에 따른 필름의 구조변화는 적외선 분광분석으로, 친수성 변화는 접촉각으로 평가하였다. 가수분해 시간이 증가함에 따라 친수성이 증가하였다. 이는 가수분해에 의해 소수성인 아세테이트기가 친수성인 수산기로 변했기 때문으로 생각되었다. 한편, 가수분해시킨 EVA 및 PVAc를 사용하여 프레스로 압착하여 제조한 필름에서는 친수성이 그다지 크게 증가하지 않았다.

• Journal of the Korean Chemical Society
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• v.17 no.3
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• pp.207-212
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• 1973

The mechanical degradation of poly (-vinylacetate) in several mixed solvents (dioxane-n-butanol, dioxane-sec-butanol, dioxane-ethyleneglycol, dioxane-kerosene.) was studied using the capillary flow method. The velocity constant of scission reaction (k) and the limited degree of polymerization (g) were compared at the same value of [${\eta}$], which is considered as the parameter of molecular dimension of polymers in solution. As result, (k) did not change much, even if the species and the volume fraction of poor (non-) solvents changed, while the value of (g) changed according to the species of poor solvents and the value of [${\eta}$]. From the facts described above, It follows that the limited degree of polymerization (g) were affected by the composition and distribution of mixed solvent molecules around the polymer chain, and the value of $\alpha$ (at [${\eta}$] = $KM^a$) in the polymer solution.