The Dow Chemical Company

Jerald A Griggs

Lu H Tung

Grace Y Lo

Narrow molecular weight telechelic and/or block copolymers are prepared by anionic polymerization using multifunctional lithium initiator in combination with a C.sub.2-16 lithium alkoxide.

Polymerization process and initiator system therefor

Block copolymers having two or more blocks may be prepared from vinyl-substituted aromatic hydrocarbons and a mixed isomer mixture of 1,3-pentadiene. At least one block is polymerized from the cis and trans-isomer mixture of 1,3-pentadiene. The amount of the mixed isomer mixture of 1,3-pentadiene polymerized may be increased by including in the mixed isomer mixture a cis-isomer polymerization promoter.

Block copolymers utilizing a mixture of cis and trans-isomers of

An improved method for the polymerization of mixtures of mixed cis and trans-isomers of 1,3-pentadiene in the production of block copolymers. By continuously or incrementally adding a cis-isomer of 1,3-pentadiene polymerization promoter, using a hydrocarbon solvent with no aprotic solvents of a polar nature and not exceeding specified temperature ranges, the cis-isomer of 1,3-pentadiene is polymerized, resulting in a greater 1,3-pentadiene polymerization yield. The polymerization promoter is a vinyl-substituted aromatic monomer, for example styrene.

Process for the polymerization of mixtures of cis and trans-isomers of

.alpha.-Methylstyrene-styrene copolymer is blended with an .alpha.-methylstyrene-styrene diene block copolymer or copolymers to provide impact resistant molding material.

Growing community of inventors

Midland, MI, United States of America

Jerald A Griggs