Correlation of Decompression Time and Foaming Temperature on Cell Density of Amorphous Foamed Plastics

摘要

The correlation of decompression rate (decompression time) and foaming temperature about cell density of amorphous foamed plastic was investigated. The foaming process took up a method which a sample is made to carry out impregnation of the blowing agent by high pressure under the high temperature more than glass transition temperature, and cell nucleation and cell growth were performed by decompression after that, and cell growth was stopped by cooling, using batch foaming system. The polymethylmethacrylate (PMMA) specimens were foamed under various decompression rates and foaming temperatures based on above method. As results, it was found that cell density of foamed PMMA has time and temperature dependence that cell density increases with a decrease in decompression time and foaming temperature, and cell density decrease with an increase in decompression time and foaming temperature. And the correlation was held to the decompression time and foaming temperature, which affect cell density.