Study on foaming of PMI foam materials

PMI foam materials were prepared using two steps, bulk polymerization through free radical copolymerization and then foaming. Effects of foaming agents, nucleating agents and other additives on the microstructure of PM I foam materials were investigated. Nucleating agents could markedly eliminate air bubbles amalgamation. When the mass ratio of the nucleating and foaming agent was 1:3, foaming multiple was the highest. Addition of other additives could do help to foaming, which induced transparent closed-cellular PMI foam materials with uniform cell diameter and distribution. When foaming time was increased, the microstructure of PM! foam materials remained unchanged, the mechanical properties of PMI foam materials were increased because the content of the imide ring was increased.