Visualization Study of Solid Poly (Ester-Amine Salt) Precursor Foaming Process

Abstract

In this research, solid poly (ester-amine salt) precursor was used to prepare polyimide foams. The foaming process was observed by microscope, and effects of particle size on bubble growth were highlighted. The results showed that the powder particles with a size between 25 and 150 μm favor to grow into single bubble mesostructure, and the ones which grow into a multi-bubble mesostructure beyond this size. On the contrary, the bubble growth terminated when the particle size below 25 μm. Sieving was an effective method to narrow size distribution and uniform the particle size, which is of benefit to the formation of polyimide foams. After filtrated with 100 mesh sieve, the retreated particles were situated in optimal band to produce polyimide foams with single bubble mesostructure.