Polyurethane elastomer was prepared from polycaprolactone (PCL), diphenylme
thane diisocyanate (MDI), 1, 4-butanediol (1, 4-BD) and Trimethylolpropane
(TMP) by prepolymer method. This amine catalyst was used:1, 4-diazabicyclo-
(2, 2, 2) octane (DABCO). Effects of the catalyst on molecule structure and
physical properties of polyurethane elastomer were also studied. When a ca
talyst was used, the reaction rate was rapider than with the non-catalyzed
system. In the observation of the polarizing microscope, some spherulites o
f small hard segments were found dispersed in the soft segments. In the def
ferential scanning calorimetry (DSC) measurements, the transition width whi
ch originated from the glass transition temperature (T-g) of amorphous hard
segments become larger, and it became clear that phase mixing of the hard
segment advances. In the mechanical properties, by using amine catalyst, th
e elastic modulus in the extension rose in comparison with non-catalyzed PU
E, and the build-up of the stress was observed in the extension over 300%.
A remarkable elongation drill effect was shown. Also, the stress relaxation
slowed down, and so the stress continued throughout the long term and the
elasticity rose.