Hydrogenated block copolymers of butadiene containing a block of 1,4 and a block of 1,2-microstructure

摘要

The composition described herein is a hydrogenated polymer derived from a butadiene diblock copolymer having 85-100%, preferably 95-100% 1,2-structure in one block and the other block comprising essentially 1,4-butadiene. The 1,2-block comprises at least 10%, preferably at least 25%, of the total weight of the diblock copolymer. The hydrogenated product is an elastomeric material which is oxidation-resistant and stable against ozone. Moreover, since the original polymer may be made by a method which permits control of the molecular weight, the molecular weight of the ultimate hydrogenated product is also controllable. The control of molecular weight and microstructure give highly desirable properties in the ultimate elastomeric product, and also control of tacticity and crystallinity.