Segmented polyurethanes

Poly(hexamethylene adipate)／liquified 4

4'-methylenedi(phenylisoeyanate) (L-MDI)／butanediol(PHMA／L-MDI／BDO)were prepared by a two-step process．and their structure and shape memory effect were investigated by DSC、WAXD testing．the tensile mechanical．dynamical mechanical properties were discussed also in this paper．It was found that the hard segment regions of these PUs were amorphous．and the soft segment ones were crystalline．The samples exhibited obvious shape memory behavior with shape recovery temperature around 35—45℃．The strain fxity was close to 100％．and the maximum shape recovery rate was mole than 97％．The sample showed high tensile strength

28—50 MPa

and large elongation at break

900％～1400％

aI room temperature．Dynamic mechanical tests indicated that the modulus at room temperature was about 140 times as high as that in the rubbery platean region．it shown an excellent dynamical property．