• Korean Membrane Journal
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• 제7권1호
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• pp.19-27
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• 2005

PP hollow fiber membrane was hydrophilized by EVOH dip coating followed by low temperature plasma treatment and UV irradiation. EVOH coating attained high water flux without any prewetting but its stability did not guaranteed at high water permeation rate. At high water permeation rate, water flux declined gradually due to swelling and delamination of the EVOH coating layer causing pore blocking effect. However, plasma treatment reduces the swelling, which suppress delamination of the EVOH coating layer from PP support result in relieving the flux decline. Also, UV irradiation helped the crosslinking of the EVOH coating layer to enhance the performance at low water permeation rate. FT-IR and ESCA analyses reveal that EVOH dip coating performed homogeneously through not only membrane surface but also matrix. Thermogram of EVOH film modified plasma treatment and W irradiation show that crosslinking density of EVOH layer increased. Chemical modification by plasma treatment and UV irradiation stabilized the hydrophilic coating layer to increase the critical flux of the submerged membrane.

• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.71-73
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• 2008

The development of polymer/inorganic nanocomposites has attracted a great deal of interest due to the improved hybrid properties derived from the two different components. Various nanoscale fillers have been used to enhance polymer mechanical and thermal properties, such as toughness, stiffness, and heat resistance. The effects of the filler on the final properties of the nanocomposites are highly dependent on the filler shape, particle size, aggregate size, surface characteristics, polymer/inorganic interactions, and degree of dispersion. In this paper, we describe the influence of different $CaCO_3$ dispersion methods on the thermal properties of polyethylene terephthalate (PET)/$CaCO_3$ composites: i.e., the adsorption of $CaCO_3$ on the modified PET surface, and the hydrophobic modification of the hydrophilic $CaCO_3$ surface. We prepared PET/$CaCO_3$ nanocomposites using a twin-screw extruder, and investigated their thermal properties and morphology.

• 대한의용생체공학회:의공학회지
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• 제10권1호
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• pp.43-52
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• 1989

We modified polymer surfaces, polyethylene, polystyrene and polyester, to improve cellcompatibility. For surface modification of the polymers, we used various surface treatment methods; physicochemical oxidation methods such as plasma discharge, corona discharge, sulfuric acid and chloric acid treatments, and biological methods such as adsorption of plasma protein and fibronectin onto the polymer surfaces. The treated polymer surfaces were characterized by electron spectroscopy for chemical analysis ( ESCA ). The physicochemically treated polymers showed different surface chemical structures depending on the treated methods. The sulfuric acid-treated surfaces showed greater carboxyl groups than those of plasma- or corona- treated surfaces, while the chloric acid-treated one showed high density of hydroxyl group on the surface. By the biological treatments, the surfaces were uniformly coated with proteins. The fibronectin adsorbed on the surface seems to have unique properties for cell binding.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.418.1-418.1
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• 2002

Recombinant interferon alpha is widely used for the treatment of diseases including chronic hepatitis C. However. it has drawbacks such as relatively short serum half-life and rapid clearance like other therapeutic proteins. Using PFGylFltioo which is one of the well-established methods to fulfill the requirements of a long-lasting form of protein. wIe prepared mono-PEG modified interferon alpha-2a in which polyethylene glycol moiety was covalently attached to the amino groups of interfelon alpha-2a. (omitted)

• 전기화학회지
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• 제11권2호
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• pp.125-129
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• 2008

리튬이온폴리머전지는 휴대용 전자기기와 전기자동차 등의 차세대 동력원으로 주목을 받고 있다. 본 연구에서는 폴리에틸렌 분리막에 소량의 부기 화합물과 고분자를 코팅하여 제조된 표면 개질 분리막을 리튬이온폴리머전지에 적용함으로써 전지 특성을 향상시키고자 하였다. 불화 알루미늄과 아크릴로니트릴-메틸 메타크릴레이트 공중합체를 폴리에틸렌 지지체에 코팅하여 얻어진 표면 개질 분리막을 이용하여 제조된 리튬이온폴리머전지는 충 방전 싸이클 과정 중에 균일한 전도성 고체 전해질 계면이 전극 표면에 형성되어 낮은 계면 저항값을 보였으며, 이에 따라 불화 알루미늄을 포함하고 있지 않는 리튬이온폴리머전지와 비교하여 싸이클 특성과 고율 방전 특성이 크게 향상되었다. 표면 개질된 분리막을 이용하여 제조된 리튬이온폴리머전지를 0.5 C rate로 충 방전한 결과, 초기 방전용량 150 mAh/g을 나타내었으며, 300싸이클에서 133 mAh/g의 방전 용량을 유지하여 우수한 용량 보존특성을 나타내었다.

• 자원리싸이클링
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• 제14권3호
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• pp.55-62
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• 2005

굴 양식의 부산물인 패각과 혼합 폐플라스틱을 이용하여서 패각의 함유 및 패각 표면 재질에 따른 물성과의 상관관계에 관한 연구를 하였다. 먼저 패각과 순수 LDPE를 twin screw extruder를 시용하여 40 wt%의 마스터배치(masterbatch, M/B)를 제조한 후, 다시 이를 순수 LDPE와 섞어서 패각 함유 10 wt%에서 40 wt%까지의 사출용 시편을 제조하였다. 한편 순수 LDPE 대신에 혼합 폐플라스틱을 이용하여 상기와 동일한 방법으로 사출용 시편을 제조하였고, 패각과 혼합 폐플라스틱과의 상용성을 향상시키기 위해서 패각의 표면을 양이온과 양이온성 계면활성제로 치환하였다. 표면 개질 패각을 이용하여 혼합 폐플라스틱과의 혼입을 통해 상기와 동일 함량을 갖는 사출 시편을 제조한 후 기계적 물성을 측정하였다. 측정 결과 표면을 개질한 패각을 함유한 혼합 폐플라스틱은 미개질 패각 함유 시편에 비해 매트릭스와의 상용성 증가로 인해 굴곡강도, 압축강도, 열변형 온도 등의 물성 향상을 나타내었다. 따라서 패각을 함유시 혼합 폐플라스틱의 기계적 물성의 향상으로 인해 새로운 용도 개발이 가능한 것을 확인하였다.

• Macromolecular Research
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• 제13권2호
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• pp.120-127
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• 2005

Conventional poly(methyl methacrylate) (PMMA) bone cement has been widely used as an useful biopolymeric material to fix bone using artificial prostheses. However, many patients had to be reoperated, due to the poor mechanical and thermal properties of conventional PMMA bone cement, which are derived from the presence of unreacted MMA liquid, the shrinkage and bubble formation that occur during the curing process of the bone cement, and the high curing temperature ($above 100^{\circ}C$) which has to be used. In the present study, a composite PMMA bone cement was prepared by impregnating conventional PMMA bone cement with ultra high molecular weight polyethylene (UHMWPE) powder, in order to improve its mechanical and thermal properties. The UHMWPE powder has poor adhesion with other biopolymeric materials due to the inertness of the powder surface. Therefore, the surface of the UHMWPE powder was modified with two kinds of silane coupling agent containing amino groups (3-amino propyltriethoxysilane ($TSL 8331^{R}$) and N-(2-aminoethyl)-3-(amino propyltrimethoxysilane) ($TSL 8340^{R}$)), in order to improve its bonding strength with the conventional PMMA bone cement. The tensile strengths of the composite PMMA bone cements containing $3 wt\%$ of the UHMWPE powder surface-modified with various ratios of $TSL 8331^{R}$ and $TSL 8340^{R}$ were similar or a little higher than that of the conventional PMMA bone cement. However, no significant difference in the tensile strengths between the conventional PMMA bone cement and the composite PMMA bone cements could be found. However, the curing temperatures of the composite PMMA bone cements were significantly decreased.

• Journal of Microbiology and Biotechnology
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• 제26권12호
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• pp.2051-2059
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• 2016

To date, there has been no employment of a magnetoelastic (ME) biosensor method to detect Salmonella enterica serovar Typhimurium in soil. The ME biosensor method needs to be investigated and modified for its successful performance. The filtration method, cation-exchange resin method, and combinations of both methods were employed for the extraction of S. Typhimurium from soil. The number of S. Typhimurium and the resonant frequency shift of the ME sensor were then compared using a brilliant green sulfa agar plate and an HP 8751A network analyzer. A blocking study was performed using bovine serum albumin (BSA), polyethylene glycol (PEG), and casein powder suspension. Finally, the modified ME biosensor method was performed to detect S. Typhimurium in soil. The number of S. Typhimurium was significantly decreased from 7.10 log CFU/soil to 4.45-4.72 log CFU/soil after introduction of the cation-exchange resin method. The greatest resonant frequency shift of the measurement sensor was found when employing centrifugation and filtration procedures. The resonant frequency shift of the PEG-blocked measurement sensor was $3,219{\pm}755Hz$, which was significantly greater than those of the BSA- and casein-blocked ME sensor. The optimum concentration of PEG was determined to be 1.0 mg/ml after considering the resonant shift and economic issue. Finally, the modified ME biosensor method was able to detect S. Typhimurium in soil in a dose-response manner. Although these modifications of the ME biosensor method sacrificed some advantages, such as cost, time effectiveness, and operator friendliness, this study demonstrated a novel approach of the ME biosensor method to detect S. Typhimurium in soil.

• 접착 및 계면
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• 제3권3호
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• pp.7-14
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• 2002

Poly(ethylene-co-methylacrylate)(PEMA)를 KOH, 암모니아 수용액으로 가수분해, ammonolysis 시켜서 측기에 -COOK, $-CONH_2$, -COOH를 갖는 수분산 형태의 변성 폴리에틸렌(m-PE)을 제조하였다. Infrared spectroscopy, 원소 분석 및 atomic absorption 분석 등을 통하여 m-PE 측기의 종류 및 조성비를 조사하였으며 수분산액의 고형분 함량에 따른 점도 및 표면장력을 측정하였다. 제조된 수분산액은 측기의 조성에 따라 안정도, 투명도 등이 변화하였다. 측기 중에서 -COOK가 수분산에 가장 큰 영향을 주었으며 -COOK 조성비가 20 mol% 이상이 되어야 안정한 분산을 얻을 수 있었고 또한 -COOK 조성비가 높을수록 수분산액은 투명하였다. 동일 -COOK 조성비에서는 아마이드의 농도가 높을수록 탁도가 증가하여 친수성이 떨어짐을 알 수 있었다. 분산액의 고형분 함량에 따른 점도를 측정하면 -COOK 조성비가 클 경우 낮은 고형분 함량에서 급격한 점도 증가가 일어나 고분자 사슬사이의 얽힘이 쉽게 일어남을 알 수 있으며 표면장력은 -COOK 조성비가 클 경우 작은 값을 나타내었다.

• 한국포장학회지
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• 제9권1호
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• pp.33-54
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• 2003

The aim of this study was to develop a model that could be used in the design of modified atmosphere packaging (MAP) for peaches. Respiratory data at 5, 10, $20^{\circ}C$ for peaches were gathered and altered for create useful respiration model. Packaging materials were conventional low density polyethylene and polypropylene with anti-fog, and anti-fungi treatments, and thickness was $30{\mu}m$ and $50{\mu}m$ each. Permeability tests were performed to find their oxygen, carbon dioxide, water vapor transmission rate as increases in temperature. Test results were then converted to logarithm format for MAP modeling. The maximum rate of oxygen uptake increased with increasing temperature. Optimum gas composition in the package system for fruits were set according to literature and upper or lower limits of oxygen and dioxide established. To predict gas composition at certain storage time, weight of fruits, film thickness, film type, and other variables, respiration rate was studied at various storage conditions. The results of tests were used to calculate Cameron's model and converted to a cubic estimation equation. The validity of the model was tested experimentally by observing actual atmospheric changes inside packages. This result of study may be useful for designing dynamic gas exchange MAP systems for similar agricultural products.