Curing behavior and properties of benzoxazine-co-self-promoted phthalonitrile polymers

A new high-performance copolymer was successfully obtained via concerted catalysis polymerization of mono-functional benzoxazine (P-a) and self-promoted 4-aminophenoxy phthalonitrile (4-APN) monomers. The FTIR and DSC curves of the P-a/4-APN in different blend ratios suggested that the monomer blends can be completely cured without the addition of curing additive. The P-a/4-APN copolymers were cured at relatively lower curing temperatures and time. The TGA curves revealed that the P-a/4-APN copolymers have good thermal stability in terms of T-5, T-10, and char yield. A gradual increase in the glass transition temperature (T-g) values and decline were seen in the storage modulus as the loading of 4-APN was increased from 10 to 30 wt % in the copolymer. The SEM analyses showed that copolymer's fracture surface is dendritic, showing the stress has been dispersed to a certain extent. The study revealed that the poly(P-a/4-APN) copolymer have much better thermal stabilities than the poly(P-a), and the prepared copolymer can be used as a high-performance thermosetting resin. (C) 2018 Wiley Periodicals, Inc.