• Macromolecular Research
• /
• 제17권12호
• /
• pp.950-955
• /
• 2009

The physical and rheological properties of thermoplasticized irradiation-crosslinked polyethylene foam using supercritical methanol treatment were investigated by GPC, FTIR, DSC, WAXS, DMTA and UDS. The polyethylene foam was selectively decrosslinked into thermoplasticized polyethylene in an appropriate supercritical methanol condition without any undesirable side reactions such as oxidation and disproportionation. The thermoplasticization was promoted with increasing reaction temperature to reach completion above $380^{\circ}C$. The supercritical reaction condition affected the crystallization behavior, and mechanical and rheological properties of the decrosslinked polyethylene foam, but not its crystallographic structure or crystallinity.

• 한국전기전자재료학회논문지
• /
• 제15권8호
• /
• pp.687-694
• /
• 2002

In order to replace the jacket material for URD power cables, the 6 kinds of polyethylene compounds were manufactured and evaluated. The characteristics of the compounds were investigated by water vapor transmission (WVT) test, thermal and mechanical test. In WVT test, all the polyethylene compounds showed the superior water resistance to conventional PVC. The molecular structure and density of polyethylene play an important role in WVT. Also, the polyethylene compounds showed the suitable characteristics in thermal and mechanical test. Especially, the linear polyethylene compounds showed the superior characteristics to LDPE ones. Due to the fillers in compounds, the abrasion resistance was decreased and the cut-through resistance was increased. From this study, it can be considered that the polyethylene compounds may be suitable to jacket material for URD power cables.

• 한국식품영양과학회지
• /
• 제28권2호
• /
• pp.423-428
• /
• 1999

Potato starches were hydroxypropylated with 2.5, 5.0, 7.5, and 10.0% propylene oxide(PO) to improve mechanical properties of starch polyethylene film. Starch polyethylene cast films were prepared that contained 5% or 10% of the hydroxypropylated potato starch. Mechanical properties of these films were measured and compared to those of the films containing native potato starch. DS(degree of substitution) increased proportionally as propylene oxide concentration increased. Relative crystallinity in X ray diffraction patterns was decreased and starch granule observed by scanning electron micro scopy was destroyed by severe hydroxypropylation. In color properties of films, b value was not significantly different in the films but 5% starch polyethylene films with 2.5 PO starch showed the lowest L and a value. Tensile strength and strain energy of the films except the film containing 10.0 PO starch were higher than those of the containing native starch.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.52-56
• /
• 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

• Journal of Pharmaceutical Investigation
• /
• 제16권1호
• /
• pp.8-11
• /
• 1986

There have been many difficulties in utilization of polyethylene (PE) container for volatile ingredients because of its high permeability. We selected glycol-modified polyethylene terephthalate (PETG) lately being used and evaluated the stability of 0.5% chlorobutanol solution for PETG. We used PE bottle, glass flask and rubber stoppered vial for comparison and assayed chlorobutanol contents of the samples stored at various temperatures for nine weeks by HPLC method. The results indicated that the stability of chlorobutanol in PETG container was almost similar to that in glass flask, and was superior to that in PE bottle and rubber stoppered vial.

• 약학회지
• /
• 제29권2호
• /
• pp.70-75
• /
• 1985

The influence of polyethylene glycol derivatives on heparin release from cylindrical monolithic type silicone segment devices was examined in physical saline solution. This water-soluble carrier caused the devices to absorb the water in aqueous media. The release rate of heparin from the devices was increased as molecular weight of polyethylene glycol was increased. Water soluble carrier incorporated into silitone segment devices permits controlled release of heparin that otherwise would be released extremly slowly from the polymer. Heparin released from the silicone segment containing polyethylene glycol showed the first-order kinetics. Without changing the release-pattern, the release rate of heparin could be controlled by varing molecular weight of polyethylene glycol, the water-soluble carrier and depleting polyethylene glycol on the outlayer of devices. The mechanism of release probably showed the creation of pore or microdomine through the devices secondary to the swelling.

• 대한전자공학회논문지
• /
• 제13권4호
• /
• pp.6-11
• /
• 1976

beewax와 polyethylene을 혼합한 모체에 탄색 및 연분말을 징량첨가시켜서 정특성감온소자를 제조하였다. C.(beewax·Polyethylene)시편은 온도범위 20°∼90℃에서 104-1010Ωcm의 PTC특성을 나타내었으며 제조과정상에 분말혼합 및 가압냉각방법를 도입함으로써 그 재현성과 안정성을 현저히 개선시킬 수 있었다. 또한 Fe-(betwax· polyethylene)시편은 같은 온도범위에서 102-1010Ωcm의 PTC특성을 나타내었으며 저저항범위에서 PTC효과를 얻을 수 있었다. The carbon (the iron) -beewax·polyethylene thermistors have been prepared by heating the well ground mixture of carbon (iron), beewax and polyethylene at 160℃ for one hour and by cooling it under pressure of 12kgw/cm2. The resistivity for the former (the latter) increased from 102Ω·cm (104Ω·cw) to 1010Ω·cm(1010Ω·cm) as temperature changed from 20℃ to 90℃. The resistivity, 102Ω·cm at room temperature for the former, was lower by order Q( two than that for the papostor made by the earlier reporter. The reproducibility, which has been an important Problem for this type of thermistors to be industrialized, was improved by introducing pressure in cooling procedure for both carbon and iron thermistors.

• 한국도로학회논문집
• /
• 제15권4호
• /
• pp.43-51
• /
• 2013

PURPOSES : The main purposes of this study are to examine the influences of polyethylene wax-based WMA additive on the optimum asphalt content of warm-recycled asphalt mixture based on the Marshall mix design and to evaluate performance of warm-recycled asphalt mixture containing 30% RAP with polyethylene wax-based WMA additive. METHODS: Physical and rheological properties of the residual asphalt were evaluated in terms of penetration, softening point, ductility and performance grade (PG) in order to examine the effects of polyethylene wax-based WMA additive on the residual asphalt. Also, To evaluate performance characteristics of the warm-recycled asphalt mixtures using polyethylene wax-based WMA additive along with a control hot-recycled asphalt mixture, indirect tensile strength test, modified Lottman test, dynamic immersion test, wheel tracking test and dynamic modulus test were conduced in the laboratory. RESULTS : Based on the limited laboratory test results, polyethylene wax-based WMA additive is effective to decrease mixing and compacting temperatures without compromising the volumetric characteristics of warm-recycled asphalt mixtures compared to hot-recycled asphalt mixture. Also, it doesn't affect the optimum asphalt content on recycled-asphalt mixture. All performance test results show that the performance of warm-recycled asphalt mixture using polyethylene wax-based WMA additive is similar to that of a control hot-recycled asphalt mixture. CONCLUSIONS: Overall, the performance of warm-recycled asphalt mixture using polyethylene wax-based WMA additive is comparable to hot-recycled asphalt mixture.

• Journal of the Korean Wood Science and Technology
• /
• 제37권4호
• /
• pp.340-348
• /
• 2009

본 연구에서는 소경저질재를 원료로 한 목재 파티클과 폐플라스틱 중에서도 많이 발생되고 있는 열가소성 재생폴리에틸렌을 결합제로 사용하여 복합패널을 제조하였다. 목재 파티클의 크기(1/32", 1/4", 1/2")와 재생폴리에틸렌의 혼합비(10%, 30%, 50%)에 따라 복합패널을 제조하여 물성을 조사하였다. 복합패널의 밀도는 같은 혼합비에서 목재 파티클이 클수록 다소 감소하는 경향을 나타냈다. 흡수 두께팽창률과 수분흡수율은 재생폴리 에틸렌의 혼합비가 증가할수록 감소하였으며, 재생폴리에틸렌이 30% 이상 혼합될 경우 14일간의 침지실험에서 치수안정성이 매우 우수하였다. 재생폴리에틸렌의 혼합비가 증가할수록 박리강도가 높아 졌으며, 휨강도 또한 같은 경향을 나타냈다. 습윤 휨강도 실험에서 30% 이상 재생폴리에틸렌을 혼합하여 제조된 복합패널은 기건 휨강도와 큰 차이를 보이지 않았다. SEM 사진 관찰을 통해 재생폴리에틸렌이 용융되어 목재 조직 내에 일부 침투되어 쐐기 형태의 기계적 결합을 형성하고 있었으며, 목재 파티클을 감싸는 매질(matrix)로써 결합되어 있는 것을 관찰할 수 있었다.

• 한국식품영양과학회지
• /
• 제15권1호
• /
• pp.39-44
• /
• 1986

Kacdugi fermented in the subatomospheric pressure(350mmHg) and polyethylene film package to improve the quality and to investigate the effect of fermentative control at $25^{\circ}C$. Brix degree, acidity, vitamin C content and number of total microbe and Lactobacilli was determined and also, the edible period of kacdugi was checked up by sensory assessment. The increasing rate of brix degree during kacdugi fermentation was high in the subatomospheric pressure, but decreased at the last period of fermentation as same tendency to the control, and it was preferably increased at the last period of fermentation in the polyethylene film package. However, the acidity was higher in the control than sbuatomospheric pressure but it was low in the polyethylene film package. Vitamin C content was high in the control at beginning and middle period of fermentation but high in sbuatomospheric pressure, and was low in the polyethylene film package at the last period of fermentation. The number of Lactobacilli was more in the subatomospheric pressure and polyethylene film package than the control, but it was suddenly incressed for the total microbe in the polyethylene film package at last period of fermentation. The edible periods of kacdugi by the sensory assessment of sour flavor, hardness and complex flavor was second days in the control. third days in the polyethylene film package, and fifth days in the subatomospheric pressure after soaking.