Polybenzoxazine thermosets with enhanced toughness via blending with phthalazinone-bearing thermal plastic copoly(aryl ether nitrile)s

Matrix resin with excellent toughness finds extensive applications in structural material fields recently. In this article, phthalazinone-bearing copoly(biphenyl ether nitrile) (PPBEN) was synthesized, followed by solution blending with commercial benzoxazine resins to enhance their toughness. The relationship between loading amount of PPBEN and combined performance of the blend system was systematically detected via the characterization of their curing behavior, thermal properties, mechanical properties, and surface morphology. The results indicated that the presence of PPBEN significantly improved the impact strength of polybenzoxazine (PBOZ) when with 10% PPBEN loading, the impact strength of PPBEN/PBOZ blends was 202% higher than that of neat PBOZ. Simultaneously, the blending system maintained a commendable flexural strength, modulus, glass transition temperature, and thermal stability. The morphology study suggested that PPBEN microparticles dispersing uniformly in bulk played an important role in releasing external energy and were responsible for final toughness during impact process. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48508.