• 한국정밀공학회지
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• 제16권9호
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• pp.18-24
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• 1999

Microcellular foaming is being researched as a method of maintaining and improving the mechanical characteristics of plastics as well as saving the material costs. This can not only improve the mechanical properties including impact strength of plastic by producing cells with the size of few ${\mu}$m diameters within the plastic, but also can save the material cost of plastic products with the general volumetric expansion of 2 to 10 times. But quite a long time is required for the gas to be absorbed in the plastic. Therefore consistent research should be done to reduce the saturation time of gas into the plastic and this paper provides the method of water microcellular foaming process as one of the methods using the high diffusivity of water. In addition, we can improve impact property of foamed plastic by using this method.

• Macromolecular Research
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• 제16권5호
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• pp.404-410
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• 2008

In order to obtain 'value added products' from polypropylene (PP)/waste ground rubber tire powder (WGRT) composites, PP/WGRT microcellular foams were prepared via supercritical carbon dioxide. The effects of blend composition and processing condition on the cell size, cell density and relative density of PP/WGRT micro-cellular composites were studied. The results indicated that the microcellular structure was dependent on blend composition and processing condition. An increased content of waste ground rubber tire powder (WGRT) and maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) reduced the cell size, and raised the cell density and relative density, whereas a higher saturation pressure increased the cell size, and reduced the cell density and relative density. With increasing saturation temperature, the cell size increased and the relative density decreased, whereas the cell density initially increased and then decreased.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.351-352
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• 2007

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1187-1188
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.213-214
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• 2008

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.57-58
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• 2008

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1367-1370
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• 2005

Microcellular foam processing of polymers requires a nucleated cell density greater than $10^9\;cells/cm^3$ so that the fully grown cells are smaller than 10 mm. A microcellular foam can be developed by first saturating a polymer sample with a volatile blowing agent, followed by rapidly decreasing its solubility in the polymer. In general, the cellular structure of crystalline polymer foams is difficult to control, compared to that of amorphous polymer foams. Since the gas does not dissolved in the crystallites, the polymer/gas solution formed during the microcellular processing is nonuniform. Moreover, the bubble nucleation is nonhomogeneous because of the heterogeneous nature of the crystalline polymer. In this paper, the effects of the crystallinity and morphology of crystalline polymers on the microcellular foam processing and on reflectivity of products are investigated. First, polymer specimens with various morphology and amount of solved blowing agent were prepared by varying the saturation pressure, saturation time and foaming condition. Then, cell morphologies according to several conditions were studied. The specimens with differing gas amount of solved and morphologies were foamed and their cellular structures were compared. The experimental results of reflectivity are compared to raw specimen and another specimen of different experimental conditions. After the experiments, recognize whether how reflectivity changes according to solved gas amount. And the effect of cell density and cell size on reflectivity is studied

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1366-1369
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• 2003

Today, the industries use polymer material for many purpose. Specially, it is important in automobile industry because tile costs of polymer hold high proportion of the overall cost. If we reduce the weight of automobile, fuel efficiency of car is raised and cost of bumper is lower. Therefore there are many efforts to reduce of car currently. The purpose of this paper is to reduce polymer used in car bumper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.421-422
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• 2006

According to the industrialization the using of polymers is increased by their mechanical or commercial demands. At now, the using of polymers is become bigger and bigger than yet. On the other words, our whole life is covered by the polymers. Due to the extended polymer using, the material cost is higher and higher. Therefore, the people used the polymer foaming process using the gas. The polymer foaming using the pentane or butane gas is prohibited by the government cause of the explosiveness and non-environmental friendly. Therefore, the members of MIT invented the Micro-cellular Polymer Foaming in 1980. The Micro-cellular Polymers has many cells in the polymer matrix. By compare between non-foamed polymers, the Micro-cellular Polymers have low material cost, soundproof and shock less. The purpose of this study is to study the twice foamed polymer by batch process. To know the reaction by step of microcellular foaming process, we measure the density of polymer. And to viewing the cell morphology, we used the scanning electron microscopy(SEM).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.240-245
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• 2001

In axiomatic approach for design evaluation, even if a mutual relation don't appear physical mapping of high level, it can appear in process mapping of low level through coupled PVs(Process Variables), but we must solve it for correct design evaluation. This paper handle a method for solving of coupled PVs by using axiomatic approach and CBR(Case-Based Reasoning). The methodology of proposal took still more shape through the instance of MCPs(Microcellular Plastics).