High temperature resistant polymer foam based on bi-functional benzoxazine-phthalonitrile resin

With the upgrading demand of various applications, it is essential to develop rigid foams with higher temperature resistance. In the current study, a new type of bi-functional benzoxazine-phthalonitrile (BZPN) foam was successfully prepared by using azodicarbonamide (AC) as a foaming agent. The influence of AC content on the curing behaviors, foaming performances and physical properties of BZPN foams was schematically studied. It was found that AC can play two roles as a foaming agent and curing agent in the BZPN/AC systems. BZPN exhibited a self-foaming behaviour with a limited foaming efficiency, usage of AC is helpful to foaming ratio, uniform cells, and closed-sphere structure. The compressive properties of BZPN foams depend on the cell structure rather than on the density. The macroscopic shape of BZPN foam is well preserved after burning on an alcohol lamp with a core temperature over 400 degrees C. Due to its bi-functional groups, the rigid phthalonitrile structure endow BZPN foams with more superior thermal stabilities in air than other BZ foams in nitrogen. This study not only gives us a glimpse of the foaming behaviour of the bi-functional BZPN, but also enriches the family of benzoxazine and phthalonitrile foam.

Automated summary

A new bi-functional benzoxazine-phthalonitrile foam was successfully prepared with azodicarbonamide as a foaming agent, showing improved foaming efficiency and uniform cell structure. The compressive properties of the foam depend on cell structure rather than density, and it exhibits superior thermal stabilities compared to other benzoxazine foams.