Stereoregulated copolymers of butadiene and piperylene

Claim 1

Process for the production of a copolymer of 1,3-butadiene and piperylene characterized by a random distribution of monomer units in the polymer chain; vinyl unsaturation pendant to the main polymer chain which is equal to or less than 10 percent of the total unsaturation present in the polymer; enchainment of at least 95 percent of the piperylene in a 1,2-trans and 1,4-trans-stereoisomeric configuration; and selective enchainment of between about 50 and 95 percent of the butadiene monomer units in the 1,4-trans-stereoisomeric configuration; which comprises reacting a mixture of butadiene and piperylene in a solvent, said piperylene having a trans-stereoisomer content in the range of 50 to 100 percent, in the presence of an iodine-containing catalyst system comprising TiX n -xMI n -yI 2 -zAlR 3 -QLB wherein X is a halogen independently selected from the group consisting of chlorine, bromine and iodine; M is a metal from Groups IIIa and IVa of the Periodic Table of the Elements; R is a monovalent hydrocarbon radical selected from the group consisting of C 1 to C 12 alkyl, aryl, alkyl-aryl, arylalkyl and cycloalkyl radicals; LB is a Lewis Base, said Lewis Base being a thia heterocyclic compound selected from the group consisting of thiolane, tetrahydrothiapyran and alkyl substituted derivatives thereof or an oxa heterocyclic compound selected from the group consisting of tetrahydrofurans, tetrahydropyrans and alkyl substituted derivatives thereof; n is a number from 2 to 4; x has a numerical value of from 0 to 20; y has a numerical value of from 0 to 5; z has a numerical value of from 1 to 40; and Q has a numerical value of from 5 to 500; and isolating the copolymer from the solvent and catalyst.