• Polymer(Korea)
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• 제35권5호
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• pp.409-418
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• 2011

A novel silicone (Si) containing vinylic monomer, N-(3-(triethoxysilyl)propyl) methacrylamide (TESPMA), based on 3-aminopropyltriethoxysilane (APTES) and methacryloyl chloride (MCl) has been synthesized for formulation of waterborne polyurethane (WPU). Two types of vinyl group containing Si, methacryloxypropyltriethoxysilane (MPTES) and triethoxyvinylsilane (TEVS), have been used as coupling reagents for comparison of the effects of Si kinds with TESPMA on the WPU. A series of new siliconized WPU, vinyl acetate/vinyl ester of versatic acid (VAc-Veova), TESPMA, MPTES and TEVS hybrid latexes have been successfully prepared by emulsion polymerization in the presence of WPU dispersion.

• Proceedings of the Korean Fiber Society Conference
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• 한국섬유공학회 2007년도 학술발표회 논문집
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• pp.223-224
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• 2007

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• Applied Chemistry for Engineering
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• 제10권3호
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• pp.362-366
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• 1999

Membranes for biosensor were prepared from poly(vinyl chloride) (PVC)l derivatives using the solution casting method, and their gas permeabilities were studied. The polymer membranes dried slowly in air showed higher permeability coefficients than those dried in vacuum. The permeabilily coefficients of carboxylated poly(vinyl chloride) (CPVC) membranes for $O_2$ and $CO_2$ decreased as the pressure of the feed gas increased. The addition of dioctylphthalate (DOP) enhanced the permeation rates for $O_2$ and $CO_2$. For example, the permeability coefficients of CPVC membranes containing 30 wt. % DOP for $O_2$ and $CO_2$ at 100 psig were 2.03 and 0.96 Barrer, respectively, which were about 4~5 times higher than those of the membranes without DOP. Poly(vinyl chloride-co-vinyl acetate-co-vinyl alcohol) (Syn-PVCAcAl) obtained by hydrolysis of poly(vinyl chloride-co-vinyl acetate (PVCA) showed a higher permeability coefficient for $CO_2$ in the presence of DOP than that for commercial PVCAcAl, but did not show any significant difference in permeability for $O_2$.

• Clean Technology
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• 제12권4호
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• pp.191-197
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• 2006

Polymerization in supercritical carbon dioxide has been getting attention since it is easier to separate the remaining reactants from product polymer and since it is a cleaner process that produces neither wastewater nor air pollutants, compared to the conventional polymerization processes. In this study, poly(vinyl acetate) (PVAc) that is necessary in producing poly(vinyl alcohol) (PVA) with a lot of industrial applications was manufactured in the presence of supercritical carbon dioxide for the second time in the world. A poly(dimethylsiloxane)(PDMS)-derivative surfactant and three initiators were employed in the polymerization of vinyl acetate (VAc) at 338.15 K and 34.5 MPa. Investigation was carried out to find out the effect of the amounts and types of initiators and surfactants as well as the effect of reaction time on the yield and the molecular weight of PVAc. The weight average molecular weight (Mw) of PVAc was in the range of 60,000 ~ 140,000 g/mol, and the number average molecular weight was in the range of 30,000 ~ 70,000 g/mol. The yield of PVAc was spread over 10 ~ 80%, based on the amount of VAc monomer.

• Proceedings of the Korean Fiber Society Conference
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• 한국섬유공학회 2007년도 학술발표회 논문집
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• pp.307-308
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• 2007

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.697-698
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• 2005

• Macromolecular Research
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• 제13권3호
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• pp.243-252
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• 2005

The effect of the vinyl acetate (VA) content on the thermal, viscoelastic, rheological, morphological and mechanical behaviors in various blends of ethylene-vinyl acetate (EVA)/ethylene-$\alpha$-olefin copolymers was investigated using 28, 22 and $15 mol\%$ of VA in EVA. In the DSC melting and crystallization thermograms of all of the EVA systems blended with ethylene-$\alpha$-olefin copolymers, discrete peaks were observed which were related to the constituents. In the dynamic mechanical thermal analysis, the storage modulus increased with increasing content of ethylene-$\alpha$-olefin copolymers. In addition, the transition regions relating to the tan bpeaks varied with the VA content. The crossover point between G' and G" varied depending on the VA contents, and shear-thinning was more prominent in the EVA/EtBC system. In the SEM investigation, a discrete phase morphology was observed in both the EVA/EtBC and EVA/EtOC blends, but the contrast improved with decreasing VA content. However, the tensile strength and modulus improved, but the elongation at break reduced with decreasing VA content, implying that the ethylene-$\alpha$-olefin copolymers play the role of reinforcing materials. Thus, the EVA and ethylene-$\alpha$-olefin components in the copolymers are immiscible in the molten and solid states, but are nevertheless mechanically compatible.

• Journal of the Korea Safety Management & Science
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• 제17권4호
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• pp.397-401
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• 2015

In this study, analysed the characteristics of power drop and surface damage in solar cell through high temperature and humidity test in the 3 case of EVA(ethylene vinyl acetate) and 2 case ribbon thickness. The solar cells were tested during the 500hr in $85^{\circ}C$ temperature and 85% relative humidity conditions, that excerpted standard of PV Module(KS C IEC-61215). Through the EL(Electroluminescence) shots, specimen's surface have partialy damaged. Before and after high humidity and high temperature test, ribbon thickness $200{\mu}m$ EVA1 case power drop rate was 8.463%, EVA2 case was 6.667%, EVA3 case was 6.373%. In the ribbon thickness $250{\mu}m$ EVA1 case power drop rate was 6.521%, EVA2 case was 8.517%, EVA3 case was 6.019%. EVA3 case was the lowest power and FF(fill factor) drop rate at the 2 case of ribbon thickness, because EVA3 is laerger than EVA1 and EVA2 in thickness, elongation and tensile strength.

• Applied Chemistry for Engineering
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• 제20권4호
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• pp.459-463
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• 2009

In this study, physical properties of poly(vinyl acetate-co-ethylene) (VAE) emulsion were investigated by adding different amounts of di-butyl phthalate (DBP) which is a common plasticizer of VAE. The glass transition temperature $(T_g)$ of the dried plasticized VAE emulsion film, which measured by Differential Scanning Calorimeter, was decreased with increasing the DBP contents while the viscosity of the plasticized VAE emulsion was increased with the DBP contents. These results suggest that the plasticizer in the dried VAE film can prevent the strong interaction between chains, resulted by the decrease of $T_g$. In the emulsion, however, the particle sizes were swelled by the penetration of plasticizers and then its viscosity increased with the DBP content. When the DBP was added, the mechanical properties of the plasticized VAE films, such as tensile strength, elongation and creep resistance, were decreased while the water resistance was increased.

• Polymer(Korea)
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• 제38권3호
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• pp.307-313
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• 2014

The physical properties of functionalized graphene sheet (FGS)/poly(ethylene-co-vinyl acetate) (EVA) was examined with various kinds of EVA, having vinyl acetate (VA) contents in the range of 0 to 40 wt%. The compatibility between FGS and EVA was enhanced as the polar VA content of EVA increased. Thus, the dispersion of FGS in EVA became finer, and the decrease of surface resistivity and the increase of tensile modulus by the added FGS became more effective when the VA content of EVA was high. When the VA content was low, the elongation at break was reduced drastically by added FGS due to the poor adhesion of FGS/EVA interface. The crystallization of EVA was generally retarded by the interaction with dispersed FGS. However, when both the VA content of EVA and the added amount of FGS were low, the crystallization of EVA was enhanced, probably due to the predominant nucleating effect by FGS.