• Current Photovoltaic Research
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• v.8 no.1
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• pp.12-16
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• 2020

This study investigates the degradation characteristics of different material types of ethyl vinyl acetate (EVA) and polyolefin (POE) with combining transparent backsheet. To this end, we fabricated samples with structure of glass/encapsulant/transparent backsheet for each type of encapsulants, and shingled Si modules with the same structure. The samples were then subjected to accelerated test by storing under damp heat condition of 85℃ and 85% RH. As a result, encaplsulant discoloration was observed, which the transmittance of the samples with EVA decreased in a rapid rate than the samples with POE. The discoloration also affected a power degradation of the shingled modules with a reduction of current density, resulting that the module with EVA showed more drop on the efficiency than the modules with POE. Furthermore, corrosion of the soldered ribbon caused by acetic acid produced from the degraded EVA also contributed in fill factor reduction.

• Elastomers and Composites
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• v.39 no.1
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• pp.3-11
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• 2004

Plasma treatment is frequently used to increase surface functionality and surface activity. It enables to improve various surface properties such as catalytic selectivity, printability, and interfacial adhesion between various materials. Surface or the ethylene-vinyl acetate (EVA) is exposed under an atmospheric pressure plasma torch (APPT), generated by dielectric barrier discharge (DBD), and the treated surfaces are systemically investigated. Argon, air, and oxygen are used as a processing gas. Properties of the treated EVA surfaces are investigated by the zeta-potential measurements and surface free energies. It is shown that the plasma treatment leads to a drastic increase of surface functional groups of EVA, as the increase of its adhesion energy ($G_{IC}$). Therefore, it is concluded that the APPT process is an effective means to improve adhesion of EVA and polyurethane (PU).

• Elastomers and Composites
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• v.51 no.3
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• pp.212-217
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• 2016

Influence of poly(ethylene-co-vinyl acetate) (EVA) types and cure systems on cure characteristics of foaming EVA compounds were investigated. Three kind EVAs with different VA contents were employed. Influence of triallyl cyanurate (TAC) and dicumylperoxide (DCP) content on the cure characteristics were examined. The minimum torque ($T_{min}$) and delta torque (${\Delta}T$) decreased as the VA content increased. The ${\Delta}T$ was increased by adding TAC and by increasing the DCP content. For the foaming EVA compounds without TAC, the cure times such as the minimum cure time ($t_{min}$), scorch time ($t_2$), and optimal cure time ($t_{90}$) did not show a specific trend according to the DCP contents. For the foaming EVA compounds containing TAC, the cure times decreased as the DCP content increased. From the experimental results, it was found that efficienct DCP/TAC ratio for improvement of the crosslink density was 1.1~2.0.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.31-35
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• 2011

Photovoltaic modules are well known to be one of the most eco generation of electricity. But usually study solar cell. Otherwise, PV modules are also important in power generation. We have to check other subsidiary materials. In this work benefit of using optically superior encapsulation materials(EVA) in generation temperature is demonstrated. Optical characterization of three EVA products demonstrates reduced transmission in the visible ray region of the solar spectrum. It will have a decisive effect to the module efficiency. Test is shown reduction of reflectance and transmittance. Reflections is dependent on the low iron glass. It can be seen between a specific wave length(240~350mm) about 1%. Transmittance in the entire ray region of light is markedly reduced to depending on the temperature rise. The graph is shown optical properties on EVA. Transmission was reduced. about 1%.

• Textile Coloration and Finishing
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• v.30 no.3
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• pp.190-198
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• 2018

We fabricated high transmission and high scattering poly(ethylene-co-vinyl acetate)(EVA) films embedding $SiO_2$ nanoparticles to improve outcoupling efficiency in organic display. The 800nm diameter $SiO_2$ nanoparticles aggregated and formed $1.56{\mu}m$ (with ${\pm}0.853{\mu}m$ standard deviation) diameter microparticles in EVA. The total transmission of scattering film was 83.3% on Polyethylene terephthalate(PET), which was higher than reference 82.8% PET substrate. The diffuse transmission and haze of the $SiO_2$ embedded EVA film were 76.1% and 91.4%, respectively. The optimized condition was 1:1 weight ratio of $SiO_2$ nanoparticles to EVA in Tetrahydrofuran(THF) solution. When the ratio of $SiO_2$ was larger than 1, the total transmission decreased by the increase in backscattering of light due to high scattering. With the optimized condition, we could succeed to fabricate a large scale film(35m in length) with a roll-to-roll process.

• Elastomers and Composites
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• v.54 no.1
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• pp.7-13
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• 2019

Recycling of waste polyvinyl chloride plastics has attracted much attention due to environmental problems, but the poor mechanical properties, low thermal stability, frequent breakage of strands, and melt cracking of the waste plastics have limited their widespread use. To overcome these disadvantages of waste PVC (W-PVC), recycled PVC powder blend was prepared by adding high-density polyethylene (HDPE) and ethylene vinyl acetate (EVA) as a heat stabilizer and compatibilizer, respectively. An intermeshing co-rotating twin screw extruder was used to prepare the blend, and the characteristics of the blend were analyzed by SEM and TGA, and by using a UTM and Izod impact tester. The impact strength was improved as the EVA content increased for the W-PVC/HDPE (80/20 wt%) blend. As the HDPE and EVA contents increased in the W-PVC/HDPE/EVA blend, the impact strength increased. SEM observations also revealed the improved interfacial adhesion for the EVA-containing blend.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.365-370
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• 2013

Generally, photovoltaic modules consist of glass, EVA, Solar Cell, back sheet and ribbon. But EVA, solar cell, ribbon affect electric output with temperature. EVA is a change in the transmittance of light from the sun. In addition, the solar cell output is decreased with temperature and the ribbon increases resistance. Transmittance and reflectance of glass and EVA were measured. In this paper, the characteristics of the components of PV module as EVA and Glass, ribbon were studied by variable temperature. effects on material properties investigated. As a result, glass is independent in temperature variation. EVA was the reduction 1~4% in transmittance. Solar cell decrease 0.469[%/$^{\circ}C$] in electric output by temperature variation. Other factors was controlled in solar cell..

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.783-786
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• 2000

In this paper, physical properties and dielectric characteristics of LLDPE and EVA which are used as a blending material to improve PE's performance are studied. LLDPE of 0.92[g/cm3] and EVA with the EVA contents of 12.5[%1 were selected as specimens, and X-ray diffraction(XRD) are used to analysis physical properties. We measured dielectric constant with the frequency range from 20[Hz] to 1 [MHz], applied voltage 6[V] and the temperature from 25[$^{\circ}C$] to 110[$^{\circ}C$]. From XRD, LLDPE has a crystallinity of 53[%] and, 46[%] for EVA. LLDPE has as low tan$\delta$ as of 10$^{-3}$ ~10$^{-4}$ and inflection point near 500[Hz]. At frequency region lower than 500[Hz], tan$\delta$ decreases with frequency and increases with temperature and it is considered to be caused by conductive carriers within specimen. Over 500[Hz], it is the reverse and we thought that it was caused by decrease of relaxation time due to Debye theory, EVA has tan$\delta$with the values of 10$^{-2}$ ~10$^{-3}$ , which is higher than that of LLDPE, and it has inflection point at 60[Hz]. It is shown that Dielectric characteristics of EVA are similar to LLDPE's.

• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.239-250
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• 2014

The purpose of this research is to implement and develop the Economic Cost Driver Size(ECDS) extended model to determine the optimal cash driver size with measurement complexity cost and allocation fail cost. ECDS model can be used to seek both measurement accuracy and time efficiency of the Activity-Base Costing (ABC). The study also develops Activity Priority Number (APN) to evaluate the importance of nonvalue-added activities improvement and to determine the representative cost driver of value-added activities when applying ECDS model. APN consists of Severity Priority Number (SPN), Undetectablitiy Priority Number (UPN) and Occurrence Priority Number (OPN). APN can be obtained from lower-stream activity, current activity, upper-stream activity in terms of hierarchical dependency of SIPOC (Supplier, Input, Process, Output, and Customer). In order to seek both efficiency of invested capital and reduction of overhead cost, the paper proposes the integrated ABC and Economic Value Added (EVA) model using redesigned ABC-based statement of comprehensive income and EVA-based statement of financial position. For a better understanding of the proposed ABC-EVA integrated model, numerical examples are demonstrated in this paper. Cost drivers of ABC and capital drivers of EVA in the proposed model can be used to reduce activity overhead cost from ABC-based statement of comprehensive income and to lessen activity capital charge from EVA-based statement of financial position.

• Macromolecular Research
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• v.13 no.4
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• pp.297-305
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• 2005

The compatibilizing effect of maleic anhydride (MA) in the immiscible blends of EVA22 (vinyl acetate content 22%)/ethylene-${\alpha}$-olefin copolymers with 1-butene (EtBC) and 1-octene (EtOC)) comonomers was studied. By adding 1, 2, and 3 phr of MA in the presence of dicumylperoxide, the morphology, tensile strength at break, and 100 and 300 % modulus of EVA22/EtBC and EVA22/EtOC blends were significantly enhanced. The melting point and crystallization point depression were observed upon the addition of MA. The changes in the ${\beta}$ transition and glass transition temperature of ethylene-${\alpha}$-olefin copolymers and ethylene-vinyl acetate copolymers, respectively, indicate that MA plays a role of compatibilizer for these immiscible blends. The TGA thermograms, measured from the blends with MA, show that thermal stability is slightly enhanced with MA, indicating that MA acts as a reinforcing agent either by grafting or crosslinking with other copolymers.