Crosslinking and mechanical property of liquid rubber. I. Curative effect of aliphatic diols

Abstract

Abstract The structure–property relationships of polyurethane elastomer derived from liquid hydroxylterminated polybutadiene/low molecular weight aliphatic diol/diisocyanate system were studied. The effects of the amount of low molecular weight diol on the mechanical properties of elastomer were discussed on the basis of the results of the stress–strain curve, swelling, dynamic viscoelasticity, x‐ray diffraction, and others. It was found that some particular combinations of low molecular weight diol and diisocyanate specifically affect the properties of elastomers. When the mechanical properties of the elastomers were plotted against the number of methylene carbons in low molecular weight diol, the characteristic zigzag patterns were obtained. These patterns were explained by the difference in the packing and the dependence of the ability of intermolecular hydrogen bonding on whether the number of the methylene carbons was even or odd. This assumption was confirmed by x‐ray diffraction.