• Polymer(Korea)
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• v.39 no.3
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• pp.433-440
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• 2015

Aluminum trihydroxide (ATH) has been commonly employed as a flame retardant for ethylene vinyl acetate (EVA) copolymers. In the present work, ATH was obtained from a recycling process of multi-layer packaging film wastes. EVA/ATH composite samples were prepared using a two roll-mill and flame retardancy of EVA/ATH composites were examined using limiting oxygen index (LOI) and flame retardancy test (UL94). We observed excellent flame retardancy in case of adding 150 phr or more of recycled ATH to EVA. Particle size and specific surface area play crucial roles in LOI value and UL-94 classification of the EVA/ATH composites. Smaller particle size and higher specific surface area of ATH was found out to improve the flame retardancy. Regarding tensile properties, crosslinked EVA/ATH compounds which is practically used for electric cables had similar to or even better tensile property values than the ones without ATH.

• Polymer(Korea)
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• v.28 no.6
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• pp.468-477
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• 2004

The polymer blends of waste poly(vinyl chloride) (RPVC) and waste polyethylene (RPE) were prepared by melt mixing. Various ethylene-vinyl acetate copolymers (EVA) and ethylene-methacrylic acid Na salt copolymer (ionomer) were used as compatibilizer. Their morphologies and mechanical properties were evaluated as a funtion of mixing sequence and time. EVA with high vinyl acetate contents showed a rapid increment of tensile properties when small amount was added. Tensile properties of the blends were gradually increased with the addition of ionomer. Morphologies of RPVC/RPE blends were analyzed by scanning electron microscopy. FT-IR data showed that EVA was a good compatibilizer in RPVC/RPE blend compared to ionomer. Mechanical properties of the blends were highly enhanced when RPVC and compatibilizer were mixed and first RPE was added later.

• Polymer(Korea)
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• v.26 no.6
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• pp.812-820
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• 2002

The positive temperature coefficient (PTC) characteristics of polymer composites were investigated with the nano-sized carbon black particles using solution tasting and melt compounding methods. The polymeric PTC composites should the electrical threshold at 35 wt% for the melt compounding method and 40 wt% for the solution casting method. The ethylene vinylacetate copolymer (EVA) composite showed a gradual increase of resistance as a function of temperature and showed a maximum at the polymer molting point. The resistance of the high-density polythylene (HDPE) composite remains unchanged with temperature but started to Increase sharply near the melting point of HDPE and showed a maximum resistance at the melting point of HDPE. The dispersion of nano-sized carbon black particles was investigated by scanning electron microscopy (SEM) and low resistance after electrical threshold, and both methods exhibited a well dispersed morphology. When the electric current was applied to the PTC composites, the resistance started increasing at the curie temperature and further increased until the trip temperature was roached. Then the resistance remained stable over the trip temperature. The secondary increase started at T$\sub$m/ of matrix polymer and kept increasing up to the trip temperature.

• Journal of Adhesion and Interface
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• v.11 no.4
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• pp.155-161
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• 2010

A series of ethylene vinyl acetate (EVA) based hot melt adhesives containing different types and compositions of tackifier resins were prepared to investigate their rheological behavior and T-peel adhesion strength on polyurethane (PU) elastomeric sheets. C5 aliphatic hydrocarbon resin (C5 resin), C9 aromatic hydrocarbon resin (C9 resin), hydrogenated dicyclopentadiene resin ($H_2$-DCPD resin), and dicyclopentadiene and acrylic monomer copolymer resin (DCPD-acrylic resin) were used as the tackifiers for the hot melt adhesives. To determine the polarity of the tackifiers, their oxygen contents were analyzed, and the DCPDacrylic resin was found to contain an oxygen content higher than the other tackifiers. Only the DCPD-acrylic resin showed complete miscibility with EVA and the homogeneous phase of the hot melt adhesive blends at all compositions. The T-peel adhesion strength between the hot melt adhesives and polyurethane elastomeric sheets was mainly affected by the polarity of the tackifier resins in the hot melt adhesives, rather than by the storage moduli, G', of the hot melt adhesives themselves.

• Journal of Pharmaceutical Investigation
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• v.25 no.3
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• pp.53-59
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• 1995

Ethinylestradiol (EE)-containing matrix was fabricated with ethylene-vinyl acetate(EVA) copolymer to control the release of the drug, Effect of addition of PEG 400 as receptor solution, the stripping of skin and Azone pretreatment on skin on the permeation of EE through the excised mouse skin was also studied. The permeation rate of EE through the excised mouse skin was affected by the PEG 400 volume fraction. The Azone pretreatment on skin didn't affect on the steady state flux, however, the lag time was shortened. The permeation rate of EE through the stripped skin was much larger than that through the whole skin. It showed that the stratum corneum acts as a barrier of skin permeation. The fact that there is little difference in EE permeation between the intact skin and the stripped skin with EVA membrane shows the permeation of EE through the mouse skin is mainly controlled by the membrane.

• Journal of the Korean Ceramic Society
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• v.31 no.7
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• pp.745-752
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• 1994

A polymer reinforced grouts using ordinary portland cement mortar and water soluble polymer{polyvinyl alcohol(PVA), styrene-butadiene rubbre(SBR), etylene-vinyl acetate copolymer(EVA)} were made. The mechanical properties of the hardened specimens were investigated through the observation of the microstructure and application of fracture mechanics. When the PVA, SBR and EVA was added with 1.5 wt% to the grouts, the compressive strength were about 54 MPa, 63 MPa and 68 MPa respectively, and the flexural strength was about 11 MPa, 12.8 MPa, and 13.6 MPa respectively, and Young's modulus was about 3.8 GPa, 4.4 GPa and 4.6 GPa respectively, and critical stress intensity was about 0.73 MNm-1.5, 0.85 MNm-1.5 and 0.9 MNm-1.5 respectively. It can be considered that the strength improvement of polymer mortar grouts may be due to the removal of macropores and the increase of various fracture toughness effects, such as grain bridging, frictional interlocking and polymer bridging.

• Journal of Pharmaceutical Investigation
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• v.28 no.1
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• pp.1-5
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• 1998

The effect of synthetic polymer membranes on the permeation rate of dideoxynucleoside-type anti-HIV drugs through hairless rat skin was studied using ethylene/vinyl acetate copolymer (EVA) and ethylene/methyl acrylate copolymer (EMA) membranes fabricated by solvent casting method. In vitro skin permeation kinetics study of DDC (2',3'-dideoxythymidine), DDI (2',3'-dideoxyinosine) and AZT (3'-azido-3'-deoxythymidine) across the (membrane/skin) composite was conducted for 24 hours at $37^{\circ}C$ using the Valia-Chien skin permeation system. The results showed that skin permeation rate of each drug across the (skin/membrane) composite was mainly dependent on the property of the membrane. Proper selection of the polymeric membrane which resembles hydrophilicity/lipophilicity of the delivering drug was important in controlling the skin permeation rate.

• Polymer(Korea)
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• v.26 no.1
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• pp.37-44
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• 2002

The polymer blends of waste polyvinyl chloride (RPVC) and waste polyethylene(RPE) were prepared by melt mixing, and their morphology and tensile properties were evaluated after the copolymers having an ethylene group in backbone and ester group in side position were added as comptatibilizers. The blend compositions were varied as follows ; RPVC/RPE 85/15 wt%, where RPVC formed a continuous phase : 50/50, mid composition : 15/85, RPE a continuous phase. The blends revealed a very low compatibility between component polymers because they showed domain sizes greater than $10\mu\textrm{m}$ over all compositions, especially the worst compatibility around mid composition. The blends showed higher compatibility when ethylene vinylacetate copolymer(EVA) and ethylene ethylacrylate-graft-methyl methacrylate copolymers(EEA-MMA) were added.

• Clean Technology
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• v.5 no.2
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• pp.45-52
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• 1999

Recycling of red mud from the aluminium manufacturing process was investigated to be utilized as plastic fillers. High density polyethylene(HDPE), low density polyethylene(LDPE) and polypropylene(PP) were found to be the suitable plastic material for which red mud can be used as fillers. With the addition of red mud the plastic showed red brown color. As the ratio of amount of red mud to plastic increased, the tensile strength increased while the Izod impact strength decreased. About five percent of ethylene vinyl alcohol(EVA) was needed as an additive to prevent the lowering of impact strength. Maleic anhydride modified polypropylene was effective for reduction of impact strength lowering of PP. Mixed waste plastics containing LDPE, HDPE, PP, polystyrene and ABS could also accommodate red mud as fillers. In this case, significant loss in mechanical properties were observed due to immiscibility between the components. Ethylene propylene rubber(EPR) and styrene butadiene styrene block copolymer (SBS) could be used to improve the impact properties of the commingled waste plastics.

• Journal of the Semiconductor & Display Technology
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• v.17 no.3
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• pp.10-16
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• 2018

In silicon crystalline PV (Photo Voltaic) industry, PV module or panel electric power is directly related to the companies' profit. Thus, many PV companies have invested and focused on R&D activities to get the higher module power. The main BOM (Bills of Material) on the module consists of PV solar cell, ribbon, EVA (Ethylene-Vinyl Acetate copolymer), glass and back sheet. Based on consistent research efforts on enhancing module power using BOM, there have been increase of around 5 watt per module every year as results. However, there are lack of studies related to enhancing accuracy of measurement. In this study, the enhancing on the metrology is investigated and the improvement shows actually contribution to company's profit. Especially, the measurement issues related to heat and to quasi state of bandgap diagram by EL(Electro Luminescence) are described in this study.