Kh. Hsieh et al., CRAFT-INTERPENETRATING POLYMER NETWORKS OF POLYURETHANE AND BISMALEIMIDE, Journal of applied polymer science, 57(3), 1995, pp. 319-327
Graft-interpenetrating polymer networks (graft-IPNs) of polyurethane (
PU) and bismaleimide (BMI) were prepared by using a simultaneous polym
erization technique. The effects of the PU molecular weight and the am
ounts of the PU on the mechanical properties, thermal stability, dynam
ic mechanical properties, density, and morphology of the IPNs are disc
ussed. The graft-IPNs exhibited superior ultimate tensile strength and
large improvement in flexural strength when the short soft segments o
f the PU were introduced. Better thermal stability of the IPNs was sho
wn by increasing the BMI content. The heterogeneous and phase-separate
d characteristics were found from the results of dynamic mechanical an
alysis. The maximum density was achieved by the graft-IPNs structure w
hen 33.3 wt % of PU with short soft chain length was added. The graft-
IPNs also showed heterogeneous morphology in the micrographs when a la
rge amount of PU was incorporated. (C) 1995 John Wiley & Sons, Inc.