Poly(vinyl butyral) based polymer networks with dual-responsive shape memory and self-healing properties

In this work, polymer networks are prepared by a simple cross-linked reaction of poly(vinyl butyral) (PVB) and hexamethylene diisocyanate. The cross-linked reaction was evaluated by Fourier transition infrared spectroscopy, degree of swelling and gel content. The polymer networks show high mechanical strength with tensile modulus and tensile strength over 1 GPa and 40 MPa, respectively, at rt. With PVB as switching domain, the polymer networks exhibit excellent thermal- and solvent-induced shape memory properties. Also, the influence of cross-linked density and solvents' properties on solvent-induced recovery speed were carefully investigated. Moreover, with the assistance of a shape memory effect, the polymer networks also show scratch self-healing behavior which was monitored using optical and scanning electron microscopy.