Poly(ε-caprolactone)-based hyperbranched polyurethanes prepared via A2 + B3 approach and its shape-memory behavior

Novel hyperbranched shape-memory polyurethanes based on F.-caprolactone were prepared via A(2) + B-3 approach with different molecular weights (M-w); the molecular weights ranged from 7.2 x 10(4) to 32.3 x 10(4) g/mol. The hard segment content was varied minimally and the B-3 monomer was also varied. The polymers were characterized by GPC, DSC, DMA, WAXD and shape-memory test. The crystallinity calculated from DSC and WAXD data indicated that the highly branched architecture does not affect the crystallization of these polymers. More interestingly the storage modulus ratios (E' ratios) of hyperbranched polymers were found to be significantly high compared to the linear analogue. As a consequence, hyperbranched polymers show 100% more shape-recovery rate compared to their linear counterpart. Antimicrobial susceptibility tests confirmed that these polymers have good antimicrobial activity which is an essential requirement of medical implants. (C) 2009 Elsevier Ltd. All rights reserved.