The nature of bonding matters: Benzoxazine based shape memory polymers

A novel shape memory polymer is presented based on polybenzoxazine and poly(e-caprolactone) (PCL). Polybenzoxazines with unbound and covalently incorporated PCL were prepared applying hydroxyl and tosyl terminated PCLs, respectively. Thermo-responsive and shape memory behavior with high shape fixity and recovery were demonstrated for samples containing a high ratio of covalently bonded PCL in a crosslinked benzoxazine structure. Samples with exclusively non-bonded PCL chains proved to be brittle, possessing a heterogeneous morphology and lacking shape memory properties. The type of bonding into benzoxazines network - covalent versus non-covalent bonding of PCL - strongly affects materials structure property relationship.