• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.149-153
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• 2003

In URD(Underground Residential Distribution) power cable, experiments of WVT(Water Vapor Transmission) test on the Base Resin accomplished to specimens which contained CB(Carbon Black), anti-oxidant to base resin and made by pressing to resin of pellet or lump form. a kind of specimens was HDPE(High Density Polyethylene), MDPE(Medium Density Polyethylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC(Polyvinyl Chloride). as a results of WVT test, we saw that WVT ratio was HDPE < LLDPE < MDPE≒LDPE${\ll}$ PVC. WVT properties of PVC using for jacket showed properties 15-20 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.52-56
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• 2001

Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB(Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC(Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE> LLDPE = MDP E> LDPE and WVT ratio was HDPE

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.489-492
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• 1997

Partial discharge characteristics of normal butyl acrylate grafted low density polyethylenes were investigated by an ultrasonic sensor made of ceramic piezoelectric material. It was found that the partial discharging activities in normal butyl acrylate grafted low density polyethylenes were considerably suppressed compared to those in plain low density polyethylene. It was found that acrylic acid grafted polyethylene was more effective than normal butyl acrylate grafted low density polyethylene.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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• pp.119-123
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• 2014

In this study, four kinds of specimens of PE(polyethylene)-based insulating materials were prepared for selecting the optimum insulation materials in a wet environment. The specimens were tested by various methods, the anti tracking test, the transmittance test in the water vapor transmittance(WVT) and the abrasion resistive test, etc. The HDPE(high-density polyethylene) specimen was showed excellent property in the tracking resistance test and the lowest transmittance in water vapor transmittance test. In the abrasion resistive test, the LLDPE(linear low-density polyethylene) and MDPE(medium-density Polyethylene) were showed excellent mechanical properties. The value of cut-through resistance for MDPE and HDPE were superior to that for LLDPE and LDPE(low-density polyethylene).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.52-56
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• 2001

Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB (Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC (Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE > LLDPE ≒ MDPE > LDPE and WVT ratio was HDPE < LLDPE < MDPE < LLDPE ≒ LDPE${\ll}$PVC. WVT of PVC using for jacket showed characteristic 15 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.122-127
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• 1963

Pyrolysis fo polyethylene and polypropylene has been studied in order to clarify the mechanism of chain scission and effect of oxygen on degradation. Rate of weight decrease was measured under nitrogen and air atmosphere at constant temperature for the samples of high density polyethylene, low density polyethylene and isotactic polypropylene, and then gaseous hydrocarbons produced from pyrolysis were analysed by gas chromatography. Although there is little substantial difference between composition of hydrocarbon gases from pyrolysis of high density polyethylene and low density polyethylene except some difference in quantity of total gas produced, gas composition from polypropylene pyrolysis differs from that of polyethylene pyrolysis. Gases from pyrolysis under air contain much more unsaturated hydrocarbons than those from pyrolysis under inert gas.

• Polymer(Korea)
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• v.25 no.6
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• pp.840-847
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• 2001

The crystallization characteristics of metallocene linear low density polyethylene (m-LLDPE)/linear low density polyethylene (LLDPE) blends were investigated. The effect of blending on the induction time for crystallization, spherulites growth rate, and maximum size of spherulites was mainly considered in this study. The formation of separate crystal which is well known crystallization behavior in LLDPE/LDPE blend was not found in m-LLDPE/LLDPE blends. The blending m-LLDPE to LLDPE caused the dramatic decrease in the induction time of m-LLDPE/LLDPE blends but it seems that the blend composition shows less effect on the induction time. Lower branching number in m-LLDPE resulted in the increasing of spherulites growth rate and the maximum size of spherulites is depend upon both the induction time and spherulites growth rate of LLDPE component affected by m-LLDPE.

• 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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• 2000.07a
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• pp.123-127
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• 2000

In order to investigate the influence of manufacturing process on the electrical properties, we used two kinds of low density polyethylene prepared using metallocene catalyst (mL), linear low density polyethylene prepared using Ziegler catalyst (LL) and low density polyethylene by high pressure process (LD). mL has the narrowest composition and molecular weight distributions. We measured the dc and impulse breakdown strengths and current densities at 3$0^{\circ}C$, 6$0^{\circ}C$ and 9$0^{\circ}C$. mL had a higher breakdown strength and a lower high-field current than LD and LL. These results were discussed from the point of manufacturing processes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.15-20
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• 2002

Quality variation of plastic pouch packing of Changran-Jeotgal produced by improved process and conventional process were investigated during storage at 10, 20 and $30^{\circ}C$, respectively. The kind of plastic pouch used in this study were polyethylene/nylon/linear low density polyethylene (PE/Ny), polyethylene terephthalatefpolyethyleneflinear low density polyethylene (PET) and low density polyethylene (PE). In the higher storage temperature, the faster increase of$ CO_2$, concentration and volume of pouch packing in all kinds of pouch. However, the highest value of pH, L-value, volatile basic nitrogen (VBN) and viable cell counts were shown in PE, the next was PET and PE/Ny, Overall, Changran-Jeotgal produced by improved process showed a little change of physical and chemical characteristics than conventional process. From above results, relationship between quality parameters were predicted pH, L-value, VBN and sensory score were highly correlated, therefore, these parameters is expected to uses as shelf-life indicated elements in cease of plastic pouch packaging.