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가스를 포함하는 고분자 재료(PETG)의 유리전이온도 변화
차성운,윤재동,Cha, Seong-Un,Yun, Jae-Dong 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.4
The industries use polymer materials for many purposes because they have many merits. But these materials' costs take up too much proportion in overall cost of products that use these materials as their major material. So it is very economical for polymer industries to reduce these costs. Microcellular foaming process appeared in 1980's to solve this problem and it proved to be quite successful. This process uses inert gases such as CO2, N2. As these gases are dissolved into polymer matrices. many properties are changed. Glass transition temperature is one of these properties. DSC, DMA are devices that measures this temperature, but these are not sufficient to measure the temperature of polymer containing gas. In this paper, we devised a new tester that uses magnetism. We used this device to acquire data of the change of glass transition temperature and made Cha-Yoon model that can predict the change of glass transition temperature. Using this model, the change of this temperature can be estimated as a function of weight gain of gas. Cha-Yoon model proved that Chow's model is inappropriate to predict the change of glass transition temperature of polymer matrices containing gas.
차성운(Cha Sung Woon),김대은(Kim Dae-eun),이수홍(Lee Soo-hong),이경수(Lee Kyung Soo),김민수(Kim Minsoo) 한국공학교육학회 2007 공학교육연구 Vol.10 No.4
현재 대학의 공학교육은 산업계 수요를 반영한 인재 양성에 적합한 교육을 하고 있지 못한 것이 현실이 며, 이에 대한 극복을 위하여 대학과 정부에서는 새로운 교육모델의 개발을 위하여 많은 노력을 하고 있다. 본 연구는 공학에서 가장 중요한 분야 중 하나인 설계분야에 적합한 현장 적응형 인재를 양성하기 위한 공학설계 교육의 방향을 살펴보는데 있다. 설계기술역량과 ABEEK의 학습성과 문항을 설문 문항으로 이용하여 산업체, 교수 그리고 학생의 입장에서 창의설계프로젝트 (3)라는 공학설계 교육을 어떻게 바라보는지 비교, 분석하여 공학설계 교육의 방향을 제시하였다. 이를 위해 휴대전화 업체의 기구설계 분야의 전문가들을 통해 설계자가 설계업무 수행을 위해서 반드시 갖추어야할 필수 역량인 설계기술역량 3요소를 선정하였 다. 또, 이 3요소에 기반한 교수의 교육목표, 학생의 학습성과 그리고 산업체에서 생각하는 교육방향을 도출하고, 이를 비교 분석한 결과 창의설계프로젝트 (3)의 공학설계 교육이 산업체의 설계분야 요구사항을 유사하게 반영하고 있음을 확인하였다. that current engineering education is insufficient to cultivate engineers who can fulfill industrial demands. Engineering colleges and the government have expended much effort to develop new education model to overcome these shortcomings. The purpose of the present research is to formulate direction of engineering design education to cultivate talented engineers meeting engineering and industrial needs. We compared and analyzed Creative Design Project (3) (a core subject in engineering design) from the feedback of practising engineers, professors and students based on essential design technology factors and the educational achievement contents of ABEEK. The three essential factors of design technology which are prerequisites for the designers to implement design work were selected by surveying experts in the field of device design of cellular phone company. Moreover, educational purpose of the professors, educational achievement of the students, and educational direction of industry needs are deduced based on the three factors. It is also ascertained that Creative Design Project (3) meets most of the requirements of industrial design field by comparing and analyzing deduced results.
초미세 발포 플라스틱의 유리전이온도를 변화시키는 가스 용해량의 영향
황윤동,차성운,Hwang, Yun-Dong,Cha, Seong-Un 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.5
The thermoforming process is widely used in the plastics industry to produce articles for the packaging, automotive, domestic construction and leisure industries. The microcellular foaming process appeared at M.I.T. in 1980s to save a quantity of polymer materials and increase their mechanical properties. The glass transition temperature of polymer materials is one of many important process variables in appling the microcellular foaming process to the conventional thermoforming process. The goal of this research is to evaluate the relation between gas absorption and glass transition temperature in batch process using microcellular foaming process. The weight gain ratio of polymer materials has a conception of gas absorption. Polymers such as acrylonitrile-butadiene-styrene(ABS), polystyrene(PS) have been used in this experiment. According to conventional Chows model and Cha-Yoon model, it was estimated with real experimental result to predict a change of glass transition temperature as a function of the weight gain ratio of polymer materials in batch process to gain microcellular foamed plastic products.