Authors: Qi Cao Pengsheng Liu
Publish Date: 2006/07/27
Volume: 57, Issue: 6, Pages: 889-899
Abstract
Hyperbranched shape memory polyurethane HBSMPU were prepared from 44’diphenylmethane diisocyanate poly butylenes adipate glycol and hyperbranched polyester as chain extender via a twostep process The morphology of the HBSMPU films was investigated by the use of wideangle Xray diffraction WAXD atomic force microscopy AFM DSC and dynamic mechanical analysis DMA It was found that the PBAG soft segments in HBSMPU with 15–35 wt of hard segments were in a crystalline state however the PBAG segments were in an amorphous state in the HBSMPU with 40 wt hard segments The increase of the hard segment content resulted in the decrease of the melt transition temperature of the HBSMPU The HBSMPU with 25 wt of hard segment content possessed highest loss tangent Heat of crystallization was dependent on the content of hard segment in the HBSMPU 96–98 wt shape recovery could be obtained for the HBSMPU with 15–35 wt of hard segment The content of hard segments in HBSMPU was very important in determining their physical properties
Keywords: