title: Triple shape memory effect of star-shaped polyurethane.
abstract: In this study, we synthesized one type of star-shaped polyurethane (SPU) with star-shaped poly(ε-caprolactone) (SPCL) containing different arm numbers as soft segment and 4,4'-diphenyl methane diisocyanate (MDI) as well as chain extender 1,4-butylene glycol (BDO) as hard segment. Proton nuclear magnetic resonance (1H-NMR) confirmed the chemical structure of the material. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) results indicated that both the melting temperature (Tm) and transition temperature (Ttrans) of SPU decreased with the hard segment composition increase. X-ray diffraction (XRD) results demonstrated that the increase of the crystallinity of SPU following the raised arm numbers endowed a high shape fixity of six-arm star-shaped polyurethane (6S-PU) and a wide melting temperature range, which resulted in an excellent triple-shape memory effect of 6S-PU. The in vitro cytotoxicity assay evaluated with osteoblasts through Alamar blue assay demonstrates that this copolymer possessed good cytocompatibility. This material can be potentially used as a new smart material in the field of biomaterials.
authors.affiliation: Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, P.R. China.
authors.forename: Xifeng
authors.initials: X
authors.lastname: Yang
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Wenxi
authors.initials: W
authors.lastname: Wang
authors.forename: Hongmei
authors.initials: H
authors.lastname: Chen
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
authors.forename: Shaobing
authors.initials: S
authors.lastname: Zhou
mesh_terms: D002152:Calorimetry, Differential Scanning; D015394:Molecular Structure; D011140:Polyurethanes / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D011140:Polyurethanes