Properties and Microstructure Study of Polyimide Foam Plastic

Five kinds of polyimide (PI) foams were prepared from dianhydride and diamine by esterification process. The microstructure of foam was characterized by SEM and visualization methods, and many properties of material were measured, including heat resistance, fire resistance, compressive strength, heat insulation and acoustic absorption. It was shown that the cell size of foam was from 1 to 1.5 mm. The cell edge of PI _BM and PI _BO foam was obscure, and the cell wall was thinner than the PI _BD , PI _OD and PI _BO-DM foam with thicker cell edge and poor cell size homogeneity. Five types of PI foams presented the trait of flexible foam plastics. All of them possess high decompose temperature, and their limiting oxygen index surpassed 40 percent, and thermal diffusion coefficients were less than 0.030 W/m·°C. In addition, PI _BO , PI _OD , and PI _BO-DM foam had excellent acoustic absorption.