• Korean Journal of Materials Research
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• v.20 no.12
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• pp.691-698
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• 2010

Magnesium hydroxide-melamine core-shell particles were prepared through the coating of melamine monomer on the surface of magnesium hydroxide in the presence of phosphoric acid. The melamine monomer was dissolved in hot water but recrystallized on the surface of magnesium hydroxide by quenching to room temperature in the presence of phosphoric acid. The core-shell particle was applied to low-density polyethylene/ ethylene vinyl acetate (LDPE/EVA) resin by melt-compounding at $180^{\circ}C$ as flame retardant. The effect of magnesium hydroxide and melamine content has been studied on the flame retardancy of the core-shell particles in LDPE/EVA resin according to the preparation process and purity of magnesium hydroxide. Magnesium hydroxide prepared with sodium hydroxide rather than with ammonia solution revealed higher flame retardancy in core-shell particles with LDPE/EVA resin. At 50 wt% loading of flame retardant, core-shell particles revealed higher flame retardancy compared to that of the exclusive magnesium hydroxide in LDPE/EVA composite, and it was possible to satisfy the V0 grade in the UL-94 vertical test. The synergistic flame retardant effect of magnesium hydroxide and melamine core-shell particles was explained as being due to the endothermic decomposition of magnesium hydroxide and melamine, which was followed by the evolution of water from the magnesium hydroxide and porous char formation due to reactive nitrogen compounds, and carbon dioxide generated from melamine.

• Journal of the Korean Ceramic Society
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• v.41 no.7
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• pp.560-566
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• 2004

To fabricate the continuously porous alumina bodies by multi-extrusion process, carbon powder and ethylene vinyl acetate were used as a pore forming agent and a binder, respectively. As the change of extrusion pass number, reduction ratio as well as the volume fraction of core and tube, the porous alumina bodies having various kind of pore size and porosity could be obtained. The porous bodies showed continuous pore shape, high specific surface as well as high bending strength, which were compared with those of commercial alumina bodies. In-vitro study was carried out using MG-63 osteoblast cells to investigate of their biocompatibility. As a result, the cells grew well on top and bottom as well as inside surface of pore. From the result of in-vivo study of 3-dimensional porous alumina bodies using rats, it was confirmed that any inflammatory response was not found in the subcutaneous tissue around porous body. Also the porous bodies removed from the rats were fully covered with well-developed fibrous tissues and showed the formation of new capillary blood vessels.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.51-56
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• 2015

The object of this study is to obtain the optimum mix proportion of halogen free compound with flame resistance and, for the purpose, thermal/electrical characteristics test are conducted using compatibilizing agents, flame resistance agents, hydroxide aluminum, sunscreen, antioxidant and silicon oil on the base resin of linear low density polyethylene (LLDPE), Ethylene vinyl acetate copolymer (EVA). Existing compound method accompanies many requirements to be satisfied including a lot of addition of flame resistance agents, prohibition of impact on mixing capability with base and property and etc. In this study, different from the existing method, the optimum mix proportion is determined and experimented by adding nano clay. Oxygen index test shows no difference between specimens while T-6, T-9 shows oxygen index of 29[%] and 26[%], respectively. This is concluded that hydroxide aluminum, which is a flame resistance agent, leads low oxygen index. From UL94-V vertical flame resistance test, the combustion behavior is determined as V-0, Fail based on UL94-V decision criteria. Viscometry shows low measurements in specimens with separate addition of compatibilizing agents or nano clay. Volume resistivity test shows low measurement mainly in specimens without compatibilizing agents. Therefore, with the flame resistance compound shows better performance for thermal/electrical property and the optimum mix proportion are achieved among many existing materials.

• Carbon letters
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• v.21
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• pp.23-32
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• 2017

A drop weight impact test was conducted in this study to analyze the mechanical and thermal properties caused by the changes in the ratio of carbon fiber reinforced plastic (CFRP) to ethylene vinyl acetate (EVA) laminations. The ratios of CFRP to EVA were changed from 10:0 (pure CFRP) to 9:1, 8:2, 6:4, and 5:5 by manufacturing five different types of samples, and at the same time, the mechanical/thermal properties were analyzed with thermo-graphic images. As the ratio of the CFRP lamination was increased, in which the energy absorbance is dispersed by the fibers, it was more likely for the brittle failure mode to occur. In the cases of Type 3 through Type 5, in which the role of the EVA sheet is more prominent because it absorbs the impact energy rather than dispersing it, a clear form of puncture failure mode was observed. Based on the above results, it was found that all the observation values decreased as the EVA lamination increased compared with the CFRP lamination. The EVA lamination was thus found to have a very important role in reducing the impact. However, the strain and temperature were inversely propositional.

• Journal of Hydrogen and New Energy
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• v.22 no.5
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• pp.706-713
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• 2011

The effects of silica-alumina type catalysts addition on the thermal decomposition of ethylene vinyl acetate (EVA) resin have been studied in a thermal analyzer (TGA, DSC) and a small batch reactor. The silica-alumina type compounds tested were kaolinite, bentonite, perlite, activated clay and clay. As the results of TGA experiments, pyrolysis starting temperature for EVA resin had the 1st pyrolysis temperature range of 300~$400^{\circ}C$ and the 2nd pyrolysis temperature range of 425~$525^{\circ}C$. The silica-alumina type catalysts did not affect the pyrolysis rate in EVA pyrolysis reaction. In the DSC experiments, addition of kaolinite and bentonite catalysts reduced the heat of fusion and heat of 2nd pyrolysis reaction. In the batch system experiments, the mixing of silica-alumina type catalysts enhanced the yield of fuel oil, and affected to the distribution of carbon numbers. In the silica-alumina type inorganic material used in this experiments, bentonite was the most effective from the pyrolysis heat, yields, and the characteristics of fuel oil.

• Archives of Pharmacal Research
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• v.21 no.5
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• pp.503-507
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• 1998

Percutaneous absorption and model membrane variations of melationin (MT) in aqueous-based propylene glycol and $2-hydroxypropyl-{\beta}-cyclodextrin $vehicles were investigatted. the excised hairless mouse skin (HMS) and two synthetic ethylene vinyl acetate (EVA) and microporous polyethylene (MPE) were selected as a model membrane. the solubility of MT was determined by phase equilibrium study. the vertical $Franz{\circledR}$ type cell was used for diffusion study. The concentration of MT was determined using reverse phse HPLC system. The MT solubility was the highest in a mixture of PG and $2-HP{\beta}CD$. The percutaneous absorption of MT through excised HMS increased as the solubility increased. However, the permeability coefficient decreased and then slightly increased in mixture of PG and $2-HP{\beta}CD$. On the other hand, both flux and permeability coefficient through EVA membrane decreased as the solubility increased. No MT was detected over 12 h after starting diffusion through MPE membrane. The flux of MT was dependent on the type of membrane selected. Flux of MT was greatest in excised HMS followed by EBA and MPE membrane. Flux of MT through EVA membrane was 5-20 times lower when compared to excised HMS. Interestingly, volumes of donor phase when MPE membrane was used, significantly increased during the study period. the HMS might be applicable to expect plasma concentration of MT in human subjects based on flux and pharmacokinetic parameters as studied previously. the current studies may be applied to deliver MT transdermally using aqueous-based vehicles and to fabricate MT dosage forms.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.76-82
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• 2013

The solar cell is a device to convert light energy into electric, which supplies power to the external load when exposed to the incident light. The photocurrent and voltage occurred in the device are significant factors to decide the output power of solar cells. The crystalline silicon solar cell module has photocurrent loss due to light reflections on the glass and EVA(Ethylene Vinyl Acetate). These photocurrent loss would be a hinderance for high-efficiency solar cell module. In this paper, the quantitative analysis for the photocurrent losses in the 300-1200 wavelength region was performed. The simulation method with MATLAB was used to analyze the reflection on a front glass and EVA layer. To investigate the intensity of light that reached solar cells in PV(Photovoltaic) module, the reflectance and transmittance of PV modules was calculated using the Fresnel equations. The simulated photocurrent in each wavelength was compared with the output of real solar cells and the manufactured PV module to evaluate the reliability of simulation. As a result of the simulation, We proved that the optical loss largely occurred in wavelengths between 300 and 400 nm.

• Resources Recycling
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• v.18 no.1
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• pp.13-21
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• 2009

A research on material separation of EVA and PET mixture plastic waste using a triboelectrostatic separator has been carried out. It was found that PP was the best charging material to give the highest charge on the surface of EVA and PET mixture plastics with an opposite polarity. Therefore, a charger of pipe line type using PP material was manufactured for separation of EVA and PET mixture plastic waste. At optimum test conditions that used PP cyclone charger developed in this study, we could separate out PET with a glade of 98.7% and a recovery of 89.7%.

• Journal of the Korean Wood Science and Technology
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• v.25 no.4
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• pp.17-21
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• 1997

This study was carried out to develop the manufacturing technique of Korean paper(Hanji) and find out new uses of machine-made Hanji produced on a a large scale by paper machine. Six kinds of Hanji were made and laminated with backpaper by acryl-based or vinyl acetate ethylene-based adhesive. Six kinds of wallpapers were made such as WH 1, WH 2-1, WH 2-2, WH 3-1, WH 3-2 and WH 4. Physical properties and quality test on the wallpapers were examined. Physical strength of the wallpapers was better than each strength of the Hanji and backpaper. It might be a roll of adhesive. And so, Production cost of the Hanji could be brought down if the Hanji was made thin to get strength not enough to cut during lamination of two papers(Hanji and backpaper). Hanji wallpapers of WH 3-1 and WH 4 are lower than a standard in sunlight resistance and WH 1 is in properties of opacity. WH 2-1, WH 2-2 and WH 3-2 were better than Korean standard in some quality tests. WH 2-2 and WH 3-2 were superior to other wallpapers as a whole. About, twenty kinds of wallpapers with surface treatment, are now being produced on the basis of these two types of wallpapers.

• Journal of the Korean Wood Science and Technology
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• v.48 no.1
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• pp.95-106
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• 2020

The purpose of this study was to determine the effects of coniferous essential oils (EOs) blended films on insect repellence and crop productivity. Low-density polyethylene (LDPE) film is widely used, especially in agriculture and for food packaging. Ethylene vinyl acetate was blended with LDPE to reduce volatilization of EOs. An EO from Japanese cypress (Chamaecyparis obtusa) was incorporated into the blend film to conduct field research on antimicrobial and insect repellent properties. Among the various concentrations of EO, the highest concentration (2.5%) showed the highest efficiency in terms of pesticidal activity. The ability to inhibit microbial growth can be explained by the lipophilic properties of the EO component, and many studies have already demonstrated this. Agricultural films containing all types of EO have been tested on various crops such as chili, cucumber, Korean melon and have been able to verify their effectiveness in avoiding pests and increasing yields. From these results, it was found that it is reasonable to use a modified film such as a composite film containing an EO for agriculture. Thus, the modified film containing EO has undoubtedly shown impressive potential for reducing the use of pesticides in a variety of ways, not only for agricultural mulching film but also for food and agricultural product packaging. This product is an environmentally friendly chemical and is safe for agricultural and industrial and food packaging applications, among others. In particular, the use of agricultural films significantly reduces the use of pesticides, suggesting that farmers can increase their incomes by reducing working hours and costs, and increasing production.