Bis-benzoxazine resins with high char yield and toughness modified by hyperbranched poly(resorcinol borate)

In this work, hyperbranched poly(resorcinol borate) (HPRB) was introduced to bis-benzoxazine (BF-a) resin to prepare a modified BF-a (mBF-a) resin with lower curing temperature, good thermal resistance and mechanical properties. The cure reaction of BF-a was catalyzed by the phenol groups in HPRB which facilitate the ring-opening process of BF-a. The char yield of mBF-a resin was increased due to the rigid backbone and boron element of HPRB. The mBF-a resin matrix composite reinforced with high silica glass cloths had excellent mechanical properties which may be benefited from the high toughness of mBF-a resin and good interfacial adhesion of the composite.