ABSTRACT
A wide spectrum of oligo- and polyisobutylenes with the polymerization degree P from 3 to 4000 and higher is obtained during polymerization of isobutylene. Oligoisobutylenes with molecular mass up to 2,000 are quite mobile liquids; low-molecular products with molecular mass from 5,000 to 50,000 are viscous liquids; high-molecular polyisobutylenes with molecular mass over 70,000 are elastomers, possessing cold flow and ability to crystallize at stretching. Beside other characteristics of thermodynamic flexibility smaller than for other non-polar polymers, for example, length of the segment equal to 1.83 nm, they indicate quite high flexibility of polyisobutylene in solution. On the other hand, concentrated polyisobutylene possesses a relatively rigid chain, the index of which is a low amplitude of vibration implying fast motion of internuclear vector C-H of the methylene group. Changing of many main properties of polyisobutylene is bound to the molecular mass and width of the MMD of polymers based on isobutylene.
