Strategies for improving the performance of diallyl bisphenol A-based benzoxazine resin: Chemical modification via acetylene and physical blending with bismaleimide

Abstract

The benzoxazine resin (DBA-a) synthesized from raw materials of 2,2′-diallyl bisphenol A (DBA), aniline and paraformaldehyde has been well-commercialized, but a reduction in its polymerization temperature and improved comprehensive properties are highly challenging to satisfy the requirements of various composites. Here, we have developed three strategies for improving the performance of DBA-a resin: the first is the chemical modification, synthesizing a novel DBA-based bisbenzoxazine containing acetylene functionality (DBA-ac); the second is the physical blend of bismaleimide (DDM-BMI) and DBA-a, forming a homogenous copolymer; and the third is combining both chemical and physical methods, achieving the DBA-ac/DDM-BMI blend as a new precursor for high-performance thermosets. The newly obtained DBA-ac possesses the advantages of relatively lower polymerization temperature and good thermal stability during the polymerization process. In addition, the polymerization temperature of DBA-ac can be further lowered by blending with DDM-BMI via multiple polymerization mechanisms. Specifically, the resulting copolymeric thermoset derived from DBA-ac/DDM-BMI blend is found to show fascinating properties such as exceptionally low coefficient of thermal expansion (CTE of 37.1 ppm/oC), high thermal stability (Tg of 370 °C), outstanding flame retardancy (THR of 17.6 KJg−1), and low dielectric constant (2.86 at 1 MHz). The current study delivers readily approaches to enhance the performance of thermosetting resins via both chemical modification and physical blending.