Abstract
For the purpose of modifying the mecahnical properties of cis-polybutadiene and natural rubbers by the addition of bulky groups to the unsaturated double bonds, the rubbers were reacted with saligenin. The reaction was carried out at 180°C under a nitrogen atmosphere in a sealed tube. The amount of combined saligenin and the change of the micro-structure were measured by elementary and infra-red analyses. Dynamic and tensile properties were investigated with the vulcanizates of those modified rubbers.
It was found that saligenin reacted with natural rubber quantitatively to give rise to a shift in the transition temperature of the modified rubber and an increase of the tensile modulus according to the amount of the saligenin charged. On the contrary, butadiene rubber did not react with saligenin but formed a large amount of gel. The cis-trans isomerization does not seem to occur in these reactions.
