Synthesis and evaluation of catalytic curing behavior of novel nitrile-functionalized benzoxazine for phthalonitrile resins

In the present embodiment, bisphthalonitrile resin has been cured using synthesized novel bisphenyl nitrile-containing benzoxazine (NBZ) vis-a-vis traditional curing agents such as 4-(3′aminophenoxy)diphenyl sulphone (m-DDS) and amino-functionalized phthalonitrile (APN) to study the curing efficacy coupled with processing window and mechanism of curing. It has been established by FT-IR and DSC that NBZ molecules cure the bisphthalonitrile resin matrix by formation of free phenolic groups which act as nucleophile triggering the curing reaction through nitrile–nitrile addition polymerization reaction. Additionally, it has been seen that NBZ-catalyzed phthalonitrile resin curing system showed better processing window in comparison to m-DDS- and APN-catalyzed system. Considering the end-user applications, the NBZ- and m-DDS-cured resins have also been studied for their TG, DMA, water uptake, thermo-oxidative and dielectric properties.