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고선택성 폴리이미드 소재의 합성 및 분자동력학 연구를 통한 기체투과도의 비교
이정무,김득주,정문기,이명건,박치훈,남상용,Lee, Jung Moo,Kim, Deuk Ju,Jeong, Moon Ki,Lee, Myung Gun,Park, Chi Hoon,Nam, Sang Yong 한국막학회 2015 멤브레인 Vol.25 No.2
In this study, gas permeability of polyimide materials having a various amine group was measured and molecular dynamics was used to analyze the dynamic characteristics of the gas molecules in the polyimide by calculating the position and velocity of the gas molecules with change of the time. The gas permeability of polyimide membrane having substitution site which increase free volume in the polymer was increased. However, polyimide with rigid structure showed decreased gas permeability. As a result of analyzing the change in the gas permeation behavior using molecular dynamics simulations, we confirmed that the results show the same tendency with actual measurements of the gas permeability. 본 연구에서는 다양한 아민기를 가지는 폴리이미드 소재 및 분리막을 제조하여 그들의 구조의 변화에 따른 기체 투과도를 측정하였으며 동력학(Molecular dynamics; MD) 기술을 이용하여 해당 기체의 시간의 변화에 따른 위치와 속도를 계산하여, 기체분자의 동적 특성을 분석하는데 활용하였다. 투과도 측정결과 합성된 고분자 소재의 경우 고분자 내의 free volume을 증가시키는 치환기를 도입시켰을 경우 기체투과도가 증가되었으나 rigid한 구조가 도입된 폴리이미드는 투과도가 감소되는 경향을 확인하였다. 또한 분자동력학 시뮬레이션을 이용하여 기체투과거동 변화를 분석한 결과 실제 기체투과도 측정결과와 유사한 결과를 나타냄을 확인할 수 있었다.
Carbamoylethyl Starch의 製造와 종이 製造時 添加效果에 관한 硏究
尹世永,崔正箕,鄭文箕,趙炳默,吳正壽 동국대학교 생명자원과학대학 연습림 1995 연습림논문집 Vol.- No.4
Recently, paper strength properties come up to be lowered by increasing ratio of utilization of recycling paper. In order to overcome these problems, strengthening agents which may cause enviromental problems have been used. Therefore, acrylamide was added to starch which is a cheap natural polymer, carbamoylethyl starch(CES) with high activity was prepared, and so the applicability as a paper additive was examined. The results are following; FT-IR spectra of CES of which degree of substitution was 0.25 showed strong C=O band at 1680㎝^-1 which corresponds the carbonyl group n amides(amide Ⅰ). Analysis of bravender viscosity showed that cooking start point of CES is 60℃ and instant viscosity is 830 B.U.(bravender unit). Effect of carbamoylethl DS on strength properties was resulted that CES of DS 0.20 appeared to be the best choice for making handsheets from KOCC with good overall strength properties, and it was selected as standard sample. Effect of pH on strength properties was obvious for their increasing values as decreasing pH. Also, a 5-fold increase in size rate as well as significant increase in wet-tensile strength were obtained in handsheets from KOCC by 3% wet-end addition of CES.