Structure of Copolymers of Isobutylene and Isoprene

Abstract By means of ozone degradation experiments it has been shown that the isoprene units in copolymers of isoprene and isobutylene unite in the 1,4 positions. This conclusion is based on negative evidence. Since no evidence was found that would indicate a tendency for the isoprene units to occur in sequences, it is concluded that one isoprene unit cannot exert any directing influence on another, as far as their relative positions along the polymer chain are concerned. The existence of such an influence would necessitate the assumption of unprecedented long-range forces. Hence, the isoprene units must enter the chain in a random manner.