• Polymer(Korea)
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• v.29 no.2
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• pp.122-126
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• 2005

The effect of Al-MCM-41 preparation methods on the catalytic degradation of linear low density polyethylene (LLDPE) was investigated. Al-MCM-41 catalysts were synthesized by direct method (Al-MCM-41-D) and post treatment method (Al-MCM-41-P) and their characteristics were elucidated by XRD, BET, $NH_3\;TPD,\;^{27}Al$ MAS NMR. TGA kinetic analysis showed that the catalytic activation energies of Al-MCM-41-D and Al-MCM-41-P were 191.54 and 114.26 kJ/mol, respectively. The higher catalytic activity of Al-MCM-41-P would be attributed to its smaller pore size as well as higher number of acid sites that are accessible.

• Journal of the Korean Applied Science and Technology
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• v.28 no.4
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• pp.386-392
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• 2011

We are crystallized to the linear low density polyethylene(LLDPE) particles by a thermally induced phase separation(TIPS). TIPS process based on the phase separation mechanism was performed for the LLDPE system which undergoes liquid-solid phase separation. The linear low density polyethylene particle formation occurred by the nucleation and growth mechanism in the metastable region. Although the growth rates depended on the experimental conditions such as the polymer concentration and temperature, the particles were larger when the polymer concentration was higher or temperature was higher. The particles were observed by SEM. The LLDPE particle size distribution became broader when the polymer concentration was higher.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.195-198
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• 1998

In this paper, the physical and the volume resistivity properties due to linear low density polyethylene(LLDPE)/ethylene vinyl acetate(EVA) blends are studied. In order to measure the volume resistivity properties. the micro electrometer is used, the range of temperature and applying voltage are 25 to 120[$^{\circ}C$], form 100 to 1000[V] respectively. From FT-IR spectrum, LLDPE blended with EVA shows an absence of carbonyl and ether groups. From the experimental result of the volume resistivity properties, it is confirmed that the volume resistivity is decreased, which was attributed to the increase of molecular motions with the increase of temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.552-555
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• 1999

In this paper, the volume resistivity properties due to mixture ration of linear low density polyethylene(LLDPE) and ethylene vinyl acetate(EVA) are studied. Electrodes is composed of upper electrode 37(mm $\Phi$), guardring electrode(inner 55(mm $\Phi$ ), and lower electrode 87(mm $\Phi$ In order to measure the leakage current, We used electrometer and stable oven with temperature controller. Measurement method is to measure the leakage current of next specimen after applying the voltage according to 'Step Apply Methods' for ten minutes. In order to measure the volume resistivity properties, the micro electrometer is used, the range of temperature and applying voltage are 25 to 100[$^{\circ}C$] to 100[V] respectively.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.87-90
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• 2011

Copyrolysis of biomass/plastic mixture was carried out from room temperature to $600^{\circ}C$ with varing the heating rates of 10, 20, and $30^{\circ}C/min$ using a thermogravimetric analyzer. Waste wood chip (WWC) and linear low density polyethylene (LLDPE) were selected as a biomass and plastic, respectively. Individual pyrolysis temperature ranges were $430{\sim}550^{\circ}C$ and $230{\sim}600^{\circ}C$ for LLDPE and WWC, respectively. For the copyrolysis of WWC and LLDPE, the decomposition temperature range of WWC was not varied, while the decomposition temperature range of LLDEP was increased to a higher temperature. The results imply that the interaction might occur between LLDEP and WWC during copyolyis of LLDPE and WWC.

• Journal of Life Science
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• v.9 no.1
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• pp.44-49
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• 1999

A study was conducted to investigate the possibility of processing seasoned and semi-dried right-eyed flounder (Pseudopleuronects herzensteini) and to examine its quality during storage at $\pm$$3^{\circ}C$ by analyzing the factors such as moisture content, pH, volatile basic nitrogen (VBN), viable cell count and peroxide value (POV). For processing of the seasoned and semi-dried product, optimum conditions of drying temperature and drying time were $20^{\circ}C$ and 4 hrs, respectively, under 50$\pm$5$\%$ of relative humidity and 2 m/sec of air blast speed. The shelf-lives of the products by vacuum-packaging method in nylon/polyethylene/linear low density polyethylene (0.015/0.045/0.040 mm) laminated film bag were 35 and 16 days during storage at $-3^{\circ}C$ and $3^{\circ}C$, respectively.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.925-931
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• 1997

An attempt was made in this study to investigate the possibility of processing seasoned and semi-dried horse mackerel (Tracharus japonnicus) and to examine its keeping quality, by analyzing the factors such as water content, pH, volatile basic nitrogen, viable cell count, peroxide value, color value and sensory evaluation. For processing of the seasoned and semi-dried product, optimum conditions of drying temperature and drying time were $20^{\circ}C$ and 4 hr, respectively, under $50{\pm}5%$ of relative humidity and 2 m/sec of air blast speed. The shelf-life of the products, vacuum-packaging method in nylon/polyethylene/linear low density polyethylene $(0.015/0.045/0.04\;{\mu}m)$ film bag, was 42 days during storage at $-3{\pm}0.5^{\circ}C$, while that of unpackaged one was only 28 days.

• Journal of the Korean Society of Safety
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• v.14 no.2
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• pp.83-89
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• 1999

The electrical properties due to mixture ratio of linear low density polyethylene(LLDPE) and ethylene vinyl acetate(EVA) films are studied. An experimental specimen is selected as LLDPE/EVA of thickness 200${\mu}{\textrm}{m}$ produced by mixture ratio of 50 : 50, 60 : 40, 70 : 30 and 80 : 2 wt%. In temperature range from $25^{\circ}C$ to 12$0^{\circ}C$, the measurement of volume resistivity using a highmegohm meter is performed within 10 minutes since each voltage of DC 100 V, 250 V, 500 V and 1000 V is applied, according to the step voltage method. From FT-IR spectrum for an analysis of physical properties, it can be confirmed that LLDPE blended with EVA shows an absence of carbonyl groups(1735 $cm^{-1}$, C=0) and ether groups(1242 $cm^{-1}$, C-O). The peak of LLDPE and EVA made of mixture ratio of 70 : 30 at 2$\theta$ =21.4$^{\circ}$ in the results of XRD is higher than the others. In the experiment for volume resistivity characteristics in order to investigate the electrical properties of specimen, it is confirmed that volume resistivity is decreased with the increase of the molecular motion and temperature.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.875-877
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• 1998

In this paper, the physical and electrical properties of electrical insulating materials due to linear low density polyethylene (LLDPE)/ethylene vinyl acetate(EVA) blends are studied. The peak of LLDPE/EVA made by blend ratio of 70:30 at $2{\theta}=21.4^{\circ}$ in the results of XRD is higher than the others. In the experiment for electrical conduction properties in order to investigate the electrical properties of specimen, it is confirmed that electrical conduction is increased with the increase of molecular motions with the increase of temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.476-480
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• 2003

Polyethylene used as insulating material of power cable is nonpolar and low dielectric loss polymer. But it has defects of tree generation and accumulation of space charge by an applied voltage resulting in the decreased life and performance. To solve these problems, mixed films with LLDPE and EVA that is similar to LLDPE at physical properties in case of low VA contents were made and tested due to the blend ratios of 80:20, 70:30, 60:40 and 50:50[wt%] respectively. We investigated AC electrical treeing characteristics to acquire the best mixture ratio and effect of the tip radius of needle electrode to develop excellent treeproof materials. The degree of crystallity calculated with XRD pattern is higher for pure LLDPE, 50:50 and 70:30. For DSC analysis, it is confirmed that the melting points of mixed specimens are lower than that of pure LLDPE and higher than pure EVA's. The shape of tree propagation showed that pure EVA was electrical tree shape of the branch type, pure LLDPE and blended specimens was able to confirm tree shape of the bush type. As the tip radius go up in the blend ratio 70:30 specimen, the tree inception voltage rise. Probably the reason is the relaxation of electric field in the specimen with bigger tip ratio. As the 6 specimens were applied AC 5[KV],7.5[KV],10[KV] respectively, tree growth length is far shorter in the specimen with blend ratio 70:30, 50:50 than in pure EVA and pure LLDPE specimen. Conclusively, it is confirmed that specimens of which blend ratio are 70:30 and 50:50 are good in electrical tree retardant characteristics, especially, 70:30 has lower dielectric loss than 50:50 and its mixture ratio is the best.