• 멤브레인
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• 제25권3호
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• pp.216-222
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• 2015

막증류(membrane distillation, MD)용 분리막의 장기 내구성능에 영향을 미치는 인자인 소수성 분리막의 젖음 현상에 대한 평가 지표로 사용되는 액체투과압력(liquid entry pressure, LEP) 측정 방법을 최적화하였다. PE (polyethylene) 분리막 및 PVDF (polyvinylidene di-fluoride) 중공사 분리막의 LEP를 측정하기 위하여 20 wt%의 고농도 염수를 제조하여 원수로 사용하고 투과수의 전도도를 모니터링하였다. PE와 PVDF 중공사 분리막의 신뢰성 있는 LEP 측정을 위해서는 5 min 이상의 holing time을 두고 주입 압력을 증가시켜야 하며, 증류수 수조의 물량대비 분리막의 면적비 또한 $10m^2/m^3$ 이상으로 부여되어야 함을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1007-1008
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• 2010

• 폴리머
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• 제38권4호
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• pp.530-534
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• 2014

다양한 기공도를 갖는 폴리에틸렌 분리막은 리튬이차전지의 격리막과 마이크로필터로 사용되고 있다. 폴리에틸렌 분리막을 대용량 리튬이차전지의 격리막에 응용하기 위해서는 고다공성 분리막의 제조가 요구된다. 본 연구에서는 열유도 상분리 공정으로 고다공성 폴리에틸렌 분리막을 제조하는데 있어, BET가 무독성 희석제로 사용 가능한지 여부를 실험하였다. 폴리에틸렌/BET 혼합물의 UCST-거동을 관찰하여 BET가 폴리에틸렌 다공막 제조용 희석제로 사용 가능함을 확인하였다. 폴리에틸렌/BET 혼합물로부터 제조된 분리막이 같은 조성에서 폴리에틸렌/파라핀 오일로부터 제조된 분리막에 비해 1.8배 높은 기공도를 나타내었다.

• 한국화재소방학회논문지
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• 제20권4호
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• pp.72-76
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• 2006

고분자/점토의 nanocomposite는 고분자에 소량의 점토를 첨가해도 물리적, 기계적, 열적 특성이 증가하기 때문에 최근 이에 관련된 연구가 증가되고 있다. 특히 montmorillonite(MMT)와 같은 smectite 계열의 점토는 높은 종횡비, 판형의 층상구조, 경제성 때문에 산업적으로 이용가치가 많다고 할 수 있다. 본 연구에서는 PE/MMT nanocomposite는 고분자를 용융시킨 후 점토를 삽입하여 시편을 제조하였다. 나노입자의 구조는 XRD 및 TEM을 이용하여 확인하였고, 난연성은 LOI, 탄화층 생성량, 연기중량농도의 측정을 통하여 검토하였다. 또한 PE/MMT nanocomposite의 열적 안정성은 DTG-DTA 분석을 통하여 검토하였다. 그 결과 종래의 화합물보다 그 특성이 보강되었다. 난연성은 연소시 탄화층 형성에 의하여 증가 되었음을 확인할 수 있었다.

• 방사선산업학회지
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• 제6권3호
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• pp.211-215
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• 2012

In this study, crosslinked polyethylene (PE) foam sheets were prepared through gamma-ray irradiation. PE foam sheets were prepared through a foaming process using sodium bicarbonate as a blowing and foaming agent. The prepared PE foam sheets were then crosslinked through gamma-ray irradiation. The crosslinking degree was increased to 86.0% with an increase in the absorption dose. The tensile strength of the crosslinked PE foam sheets was increased with an increase in the absorption dose. However, the elongation-at-break of the crosslinked PE foam sheets was decreased. The thermal decomposition temperature of the crosslinked PE foam sheets was increased to $421.2^{\circ}C$ with an increase in the absorption dose. The SEM analysis revealed that the morphology was not changed significantly after the crosslinking through gamma-ray irradiation.

• 한국수산과학회지
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• 제55권1호
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• pp.73-77
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• 2022

The shelf life of oysters Crassostrea gigas, in two different types of packaging containers, polyethylene (PE) and polyethylene terephthalate (PET), was determined by evaluating the pH, glycogen and soluble protein content, turbidity, and viable cell count. After 7 days of storage, the pH of the packing water in the PE container decreased to 5.88, while the pH in the PET container decreased to 6.03. In the PE container, the glycogen content of the oysters decreased by 0.85 g/100 g and the soluble protein content and turbidity of the packing seawater increased by 1,927.21 mg/100 g and 3.24 McF, respectively. In the PET container, the glycogen content of the oysters decreased by 0.96 g/100 g and the soluble protein content and turbidity of the packing seawater increased by 1,674.75 mg/100 g and 0.98 McF, respectively. The reaction rate constants (K) were as follows: glycogen content, -0.18 (PE) and -0.10 (PET); soluble protein content, 0.29 (PE) and 0.26 (PET); and turbidity, 0.41 (PE) and 0.06 (PET). These results suggested that PET can be used as a new packaging container material for raw oysters because the quality is maintained and it offers more convenient handling during distribution.

• 한국수산과학회지
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• 제57권3호
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• pp.227-238
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• 2024

This study aimed to evaluate the effects of polyethylene microplastic (PE-MPs) via measuring the growth performance, hematological parameters, and antioxidant responses in Korean rockfish Sebastes schlegelii exposed to waterborne polyethylene microplastic with dimensions of 22-71 ㎛. S. schlegelii (mean weight, 34.55±5.82 g; mean length, 12.59±0.79 cm) were exposed to PE-MPs at concentrations of 0, 400, 800, 1,600 and 3,200 ㎍/L for 10 and 20 days. PE-MPs significantly affected growth performance, hematological parameters, plasma components, and antioxidant responses in a concentration-dependent manner. At a concentration ≥1,600 ㎍/L, PE-MPs significantly decreased body weight gain and specific growth rate, and significantly increased the hepatosomatic index. Hematological parameters showed a significant decrease in total red blood cell count and hemoglobin levels. Plasma components showed a significant increase in glucose, aspartate aminotransferase, and alanine transaminase levels, whereas total protein, calcium, and magnesium levels significantly decreased. Exposure to ≥1,600 ㎍/L PE-MPs also induced reactive oxygen species generation in the gill and liver, significantly increasing superoxide dismutase and catalase activity. These findings suggest that exposure to ≥1,600 ㎍/L PE-MPs could significantly change growth performance, hematological parameters, plasma components, and antioxidant responses, resulting in physiological toxicity.

• 한국응용과학기술학회지
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• 제20권2호
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• pp.141-147
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• 2003

Oxidized polyethylene wax is obtained by oxidation of polyethylene wax and it is composed of various chemicals, e.g., fatty acid, alcohol, ketone and ester. The application of oxidized polyethylene wax is determined by the composition of these chemical substances. In this basic study we observed the basic reaction parameters of time, temperature, oxygen concentration and catalysts on the oxidation reaction of low molecular weight polyethylene(PE wax) by analyzing the acid value, physical and chemical properties of oxidized PE wax to develop a new oxidation process. Acid values are increased with temperature increase in the rage of $150^{\circ}C^{\sim}180^{\circ}C$ but decreased beyond 190$^{\circ}C$. Acid values are also increased with oxygen concentration. As the oxidation reaction proceeds the molecular weight and softening points of oxidation products are decreased by cracking reaction, but the viscosities are increased. To observe the crystallinity of oxidation products SEM experiment was performed. To obtain a high acid-value product in a mild condition, we adopted free radical catalysts and the acid value of the product using catalyst was higher than the product obtained without catalyst in the same reaction condition. The effective initiators were dicumyl peroxide(DCPO), t-butylperoxy-2-ethyl hexanoate(HOPO) and benzoyl peroxide(BPO) having long half-life.

• 전기화학회지
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• 제15권1호
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• pp.48-53
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• 2012

리튬 이차전지의 대표적인 분리막인 polyethylene(PE) 분리막은 열에 의한 수축 및 기계적 파열의 단점을 가지고 있다. 본 연구에서는 이러한 기존 PE 분리막을 개선하기 위해 $Si_3N_4$ 코팅 분리막 (SCS, Silicon-nitride Coated Separator)을 제작하였다. $Si_3N_4$ 코팅이 분리막의 열적/기계적 수치안정성, 이온전도도, 및 전지의 출력 특성에 미치는 영향을 알아보았다. $Si_3N_4$ 분말을 polyvinylidene fluoride(PVdF) 결착재를 이용하여 PE 분리막의 한 쪽 면에 10 ${\mu}m$ 두께로 코팅하여 SCS를 제작하였다. SCS는 PE 분리막보다 $100{\sim}150^{\circ}C$에서 우수한 열적안정성을 나타냈으며, 특히 $150^{\circ}C$에서의 수축률은 10~20% 감소를 보였다. 또한, SCS의 인장강도는 PE 분리막에 비해 증가를 보였다. SCS는 PE 분리막에 비해 다소 낮은 이온 전도도를 보였지만, $LiCoO_2$/Li 코인전지의 C-rate(0.2~3C) 특성 평가에서는 유사한 결과를 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.260-260
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• 2010

In recent years, polymer/clay nanocomposites have generated a great interest, both in industry and in academia, because they often exhibit remarkable improvement in material properties when compared with the virgin polymer or conventional micro and macro-composites. Among these properties are stiffness, strength, dimensional stability and permeability. [1-3] The dispersion of hydrophilic silicates in a hydrophobic matrix like Polyethylene (PE) is difficult because of the difference in character between PE and Montmorillonite (MMT). Therefore, it is necessary to modify PE with polar groups, which can increase the hydrophilicity of PE. In this study, High density polyethylene (HDPE)/$Mg(OH)_2$/Montmorillonite (MMT) nanocomposites having a various compositions were prepared by a melt blending technique with an internal mixer and properties namely mechanical, morpology, rheological and thermal properties were investigated