The polybutadiene polyol was prepared locally [5] with low vinyl microstructures and
Mn being about 2500 gr/mol. Polybutadiene polyol was degassed at 50 °C for 24 hr
before use. MDI (4,4-diphenylmethane diisocyanate), BDO (1,4-butane diol ) from
Merck were used after drying at 50 °C and 800 mm-Hg vacuum for 8 hr.