Jn. Hou et al., THERMALLY STIMULATED DEFORMATION RECOVERY EFFECT OF SEGMENTED POLYURETHANES, Vysokomolekularnye soedinenia. Seria A, 37(8), 1995, pp. 1377-1381
The thermally stimulated deformation recovery effect of 4,4'-diphenylm
ethane diisocyanate (MDI)- and toluene diisocyanate (TDI)-based segmen
ted polyurethanes with polycaprolactone (PCL) soft segments was invest
igated. It was found that these segmented polyurethanes may exhibit ty
pical shape memory behavior with very large recoverable deformation an
d recovery rates. Their critical recovery temperature was around 50-60
degrees C, close to the melting temperature of the PCL crystals of th
e specimens. A schematic diagram was given to describe the shape recov
ery function of these copolymers. Repeated tests indicate that, after
the destruction of some weak crosslinks in the first stretching, the p
olyurethane specimens may become dynamically ideal elastic networks, a
nd their deformation is almost completely recoverable.