Effect of Foaming Agent Concentration on Bubble Structure and Properties of Bismaleimide Foam

Bismaleimide foam using azodicarbonamide (AC) as the foaming agent was prepared through prepolymerization and foaming. The influence of AC on bubble structure, density, high-temperature dimensional stability temperature(HDT) as well as compressive properties of the bismaleimide(BMI) foam was investigated. The results show that foam density could be adjusted from 60kg/m super(3) to 280kg/m super(3) by content of AC, meanwhile, AC dosage has little influence on cell size and its distribution. As the content of AC decreases, the HDT and compressive strength increase. When the foam density is 280kg/m super(3), the HDT is 220[degrees]C, compressive strength and modulus are 4.8MPa and 200MPa respectively, meeting the requirements of the high-temperature and mechanical properties of structural foams.