A facile preparation strategy of polycaprolactone (PCL)-based biodegradable polyurethane elastomer with a highly efficient shape memory effect

We report an efficient and environment-friendly method of synthesizing biodegradable, shape memory polyurethanes via a catalyst-free polymerization process. Two different polyurethanes (poly(PCL-1,4-butanediol-urethane) PCBU and poly(PCL-5,5 ',6,6 '-tetrahydroxy-3,3,3 ',3 '-tetramethyl-1,1 '-spirobisindane-urethane) PCTU) were composed by the soft segment of polycaprolactone diol and the hard segment of non-planar ring structure/hexamethylene diisocyanate. The polyurethane products obtained were confirmed by FTIR spectroscopy and Atomic Force Microscopy (AFM). PCTU and PCBU exhibited a shape fixation rate of 99.3% and 91.1% and shape recovery rate of 98.3% and 85.1%, respectively during a triple-shape memory procedure. Notably, these PUs had superior biodegradability in buffer solution without enzyme catalysis and the biodegradation weight loss ratio of the PCBU reached 48% within 3 months in the buffer solution.