• Journal of Radiation Protection and Research
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• 제23권2호
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• pp.83-88
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• 1998

키토산은 키틴의 탈아세틸화반응을 통해서 얻어진 유전적 독성이 없는 천연착화제로써 방사성동위원소 혹은 중금속 이온의 제거제 및 체내 흡수 억제제로 알려져 왔다. 본 연구에서는 분자량이 다른 C-14 chitosan을 정맥투여 한 후 C-14 chitosan 분자량별 마우스 체내 대사과정을 알아보고자 하였다 ICR계 웅성 마우스(8-10주령, 체중 30-35g)를 사용하였다. C-14 chitosan은 증류수로 희석한 다음, 꼬리정맥을 통해 정맥 투여하였다. C-14 chitosan 투여후 6시간, 1일, 3일, 5일, 7일째 마우스를 희생시켜 혈액, 간, 신장, 비장, 폐, 근육, 고환, 오줌을 채취하였으며, 각각의 ${\beta}$-방사능을 측정하여 상대농도를 구하였다. 대부분의 C-14 chitosan이 6시간째에 오줌을 통해 체외 배출되었고, 체내대사과정은 분자량이 서로 다름에도 불구하고 비슷하였다. 간, 신장, 비장등에서 높은 방사능을 나타내었다. 조직간의 상대농도는 6시간째에 증가하다가 서서히 감소함을 알 수 있었다. 결론적으로 정맥 투여한 키토산은 분자량에 상관없이 대부분 오줌을 통해 체외배출 되고, 체내 장기중의 대사과정은 비슷하게 나타났다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Proceedings of Pre-symposium of the 10th ISWPC
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• pp.34-42
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• 1999

The present investigation has focused up on the study of the adsorption of three different molecular mass fractions of a polyDiMethylDiAllylAmmoniumChloride (DMDAAC) (8750(LM\ulcorner), 48000(MM\ulcorner) and 1200000(HM\ulcorner)) on bleached chemical fibres. Both kinetics of adsorption and equilibrium adsorption measurements have been conducted and each adsorption has been measured by polyelectrolyte titration. The results show that the LM\ulcorner polymer can reach all of the charges in the fibre wall whereas the MM\ulcorner and HM\ulcorner can only reach the external surfaces of the fibres. It is also shown that the kinetics of adsorption of the LMw polymer is not at all affected by the presence of a saturated layer of HMw polymer on the surface of the fibres. Finally, the results from the investigation show that it is possible to have full coverage of the external surface of the fibres by a high molecular mass polymer and a full coverage of the internal surface of the fibres with a low molecular mass polymer. This is true if the high molecular masspolymer is added first followed by addition of the low molecular masspolymer.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3762-3766
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• 2013

This article examines the modification of surface properties of ultrahigh-molecular-weight polyethylene (UHMWPE) with nanoscale ceramic particles to fabricate an improved composite with butadiene-nitrile rubber (BNR). Adhesion force data showed that ceramic zeolite particles on the surface of UHMWPE modulated the surface state of the polymer and increased its compatibility with BNR. Atomic force microscopy phase images showed that UHMWPE made up the microphase around the zeolite particles and formed the evolving layer with a complex interface. The complex interface resulted in improvements in the mechanical properties of the composite, especially its low-temperature resistance coefficients, thereby improving its performance in low-temperature applications.

• Macromolecular Research
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• 제17권3호
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• pp.156-162
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• 2009

Supramolecular hydrogels were instantaneously fabricated by mixing aqueous solutions of $\alpha$-cyclodextrins ($\alpha$-CDs) and amphiphilic methoxy (polyethylene glycol) (MPEG)-$\varepsilon$-caprolactone (CL) oligomer, which was synthesized via the ring-opening polymerization of the CL monomer using low-molecular-weight MPEG ($M_n$ of MPEG=2,000 g/mol) as an initiator. The supramolecular structure of the hydrogels was revealed by X-ray diffraction (XRD) analyses. Rheological studies of the hydrogels revealed an elastic character when the number of CL units in the oligomer was more than 2, and the obtained hydrogels showed high storage modulus but relatively low shearing viscosity due to the low-molecular-weight character of the oligomer, which was more preferable for use as an injectable delivery system. The physical properties of the hydrogels could be modulated by controlling the chain morphology and concentration of the oligomers, as well as the feed molar ratio of the oligomer to $\alpha$-CD. The components of the supramolecular hydrogels are biocompatible and can readily be eliminated from the body. These features render the supramolecular hydro gels suitable as drug delivery systems and tissue engineering scaffolds.

• 대한화학회지
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• 제43권1호
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• pp.28-42
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• 1999

크기가 큰 치환기의 폴리실란-[2-($R^1R^2$-phenyl)propyl]Si[$R^3$]-[예:$R^1=R^2$=H, $R^3$=n-hexyl; 폴리(2-페닐프로필)(n-헥실)실란]을 초음파 화학적 방법을 사용하여 Wurtz 축합반응에 의해 합성하였다. 초음파는 톨루엔 용매 중 금속 나트륨을 분산시켜 작은 크기와 높은 표면 활성의 나트륨을 형성하였으며 이에 의해 Wurtz 축합반응이 진행되었고 또한 초음파는 부 생성물인 염화나트륨이 나트륨 표면에 침착되는 것을 방지하여 표면활성이 지속적으로 유지되도록 하여 효율적인 반응이 기대되었다. 폴리실란 생성물은 저분자량의 중합체(분자량~$10^3$)와 고분자량의 중합체(분자량~$10^6$)의 혼합물로 얻어 졌다. 전체 수득률은 75-99% 이었으나 $R^3$가 n-hexyl기인 경우에는 혼합비율은 고분자량 중합체가 주 생성물로, cyclohexyl 또는 2-phenylethyl기인 경우에는 저분자량 중합체가 주 생성물로 얻어져 폴리실란의 치환기 종류에 영향을 받는 것으로 나타났으나 $R^1, R^2$의 변화는 영향을 나타내지 않았다.

• 산업식품공학
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• 제13권3호
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• pp.169-175
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• 2009

마치현을 압출성형 및 효소분해 처리할 경우 원료에 비하여 수용성 고분자 다당류 및 아라비노갈락탄 함량이 증가하였다. 마치현 수용성 다당류 중 아라비노스와 갈락토오스의 함량이 원료 마치현보다 1.5배 증가하였으며, 람노스 함량도 2.6배 증가한 유의적인 결과를 보였다. 압출성형 처리효과로 고분자 분획(I)은 Ext I, Ext II 및 Ext III 시료에서 각각 37, 29 및 26% 정도 저분자 분획(II)으로 분자 재배열이 발생함과 동시에 66,000-74,000 Da범위의 분자량을 갖는 다당체로 구조변형 되었다. 특히, 저분자 분획의 분자량과 조성비에 있어서 압출성형 처리한 마치현은 처리하지 않은 원료에 비하여 9-13% 정도 증가하여 유의성이 있었다. 이같은 다당류의 붕괴 및 변형 정도는 압출성형 처리시 투입된 기계적 소모 에너지와 비례적인 상관성을 보였다. 압출성형 처리를 한 수용성 다당류의 경우 압출성형 처리온도 120$^{\circ}C$ 및 140$^{\circ}C$인 경우 자유 라디칼소거활성능이 압출성형 처리하지 않은 원료에 비하여 높게 증가하였다. 상기와 같은 마치현 유래 아라비노갈락탄의 항산화 활성 기능의 결과에 비추어볼 때 보다 폭 넓은 범위의 분자량을 갖는 분획물 제조 및 생리활성 평가실험을 지속적으로 추진한다면 새로운 기능성 식품소재로 활용할 가치가 있다고 기대된다.

• Environmental Analysis Health and Toxicology
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• 제23권3호
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• pp.201-211
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• 2008

This study was performed to find the atmospheric concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) at four different heights (l0, 50, 150 and 1,500 cm) using low volume polyurethane foam (PUF) plug air sampler in semi-rural area. ${\alpha}-/{\beta}-/{\gamma}-HCH$ with low molecular weights and Koa (octanol-air partitioning coefficient) in OCPs were similarly high concentrations at all heights, but the other OCPs (p,p'-DDE, p,p'-DDD, p,p'-DDT, Heptachlor epoxide, ${\gamma}$-CHL, ${\alpha}$-CHL, Trans-nonachlor) with high molecular weights and Koa decreased with increasing heights. However, the concentrations of PCBs increased with increasing height.

• Preventive Nutrition and Food Science
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• 제7권3호
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• pp.293-298
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• 2002

Carnitine is considered a conditionally essential nutrient because dietary sources may become important under conditions which either reduce biosynthesis or increase urinary excretion of carnitine. Therefore, it is important to have a database for dietary analysis for carnitine content. Because there is limited data available for the carnitine content of Korean foods, this study was undertaken to analyze the total carnitine (TCNE) content of 146 commonly consumed Korean foods. TCNE concentrations were assayed using a modified radioisotopic method. Beef and pork contained 91.09 and 17.21 mg TCNE / 100 g weight, respectively. Fish and shellfish ranged from 0.28 to 24.87 mg TCNE / 100g weight. TCNE concentration in milk was 1.77 mg / 100 mL and cheese was 0.49 mg / 100 g weight. Cereals and pulses contained between 0 and 1.43 mg TCNE / 100 g weight. The TCNE concentration of most fruits and vegetables was between 0 and 0.7 mg 1100 g weight. However, mushrooms contained between 2.77 and 7.02 mg of TCNE / 100 g weight. Soy sauce, soybean paste and fermented red pepper soybean paste contained 1.05, 0.28 and 0.5 mg TCNE / 100 g weight, respectively. These results demonstrate that TCNE concentrations are high in meat, fish, shellfish and milk, but low or non-existent fruits and vegetables. However, mushrooms are a substantial source of vegetable derived TCNE. These data will be useful in establishing a database for determining the TCNE content of Korean diets.

• 한국염색가공학회지
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• 제29권4호
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• pp.223-230
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• 2017

Three super hydrophobic fluorescence dyes were selected to dye high molecular weight polyethylene fiber and their molar absorptivity, emission spectrum, and quantum yield were measured. From the results of color strength on the fiber, all the three dyes exhibited linear increase according to the dye concentration and Fluoro3 dye showed the highest color strength among them. Emission strength of the fluorescence dyes on the fiber was investigated according to the dye concentrations. The emission was increased with the increase of the dye concentration at relatively low dye concentration and then after showing the maximum emission strength the emission was decreased at higher dye concentrations. The highest emission was obtained in Fluoro2 dye. Color fastness to washing and rubbing was generally good enough, however, especially to light, only Fluoro3 dye exhibited rating 3 acceptable practically and Fluoro1 and 2 was ratings 1 which is unacceptable level.

• Macromolecular Research
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• 제17권4호
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• pp.240-244
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• 2009

High molecular weight(MW), 3-arm star poly(methyl methacrylate)(PMMA) with a narrow MW distribution($M_n$=570,000 g/mol, PDI=1.36) was successfully synthesized by activators regenerated by electron transfer(ARGET) atom transfer radical polymerization(ATRP). The polymerization was carried out with a trifunctional initiator/$CuBr_2$/N,N,N',N",N"-pentamethyldiethy lenetriamine(PMDETA) initiator/catalyst system in the presence of a tin(II) 2-ethylhexanoate [$Sn(EH)_2$] reducing agent at $90^{\circ}C$. The concentration of the copper catalyst was as low as 30 ppm, and a high initiation efficiency of the initiating sites was obtained. The chain-end functionality of the high MW, 3-arm star PMMA was confirmed by a chain extension experiment with styrene via ARGET ATRP, using the same catalyst system.