• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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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).

• Journal of the Korean Society for Precision Engineering
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• v.17 no.9
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• pp.196-201
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• 2000

There is a great demand for reducing the amount of material used in mass-produced plastics parts for material cost constitutes a large percentage of the total cost of a product up to 75% It may be noted that the price of plastics is directly related to the price of petroleum. Material reduction therefore decreases the amount of oil needed for the manufacture of plastics and thus help conserve this natural resource. Therefore microcellular foaming process(MCPs) was studied for solving this problems alternatively in 1980's at M. I. T. Until now in microcellular plastics processes carbon dioxide gas was mainly used for microcellular foaming Because carbon dioxide has more solubility than any other gases such as nitrogen gas or helium gas. The purpose of the this research is measurement of changing of the microcellular plastics' weight by using nitrogen gas in injection molding an comparing weight reduction of microcellular foamed plastics for using carbon dioxide gas with nitrogen gas.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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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