Atlantic Richfield Company

Harold L Nicholson

Stewart Carl Feinberg

David R Warfel

Cloudy material in organic diluent solutions of polymers prepared by anionic polymerization with a lithium initiator is removed by treating the polymer solutions resulting from the polymerization with boric acid, separating the solid material from the solutions, and isolating the polymer.

Purification of polymer solutions

A thermoplastic molding composition containing a non-equimolar copolymer containing less than 50 mole percent of an .alpha.,.beta.-ethylenically unsaturated dicarboxylic acid or its anhydride and more than 50 mole percent of a monovinyl-substituted hydrocarbon monomer and an impact modifying substance consisting of a styrene/butadiene star block thermoplastic elastomer, is disclosed.

Thermoplastic molding composition

A semi-continuous process for the preparation of star-block copolymers of 60 to 90% by weight of monovinyl aromatic compound and 10 to 40% by weight of conjugated diene monomer has been developed. The process reduces the time needed to produce the copolymer by shortening reaction time and eliminating the need for costly cleanout between runs. Novel star-block copolymers are prepared which have bimodal arm structures containing a series of tapered copolymer segments.

Semi-continuous process for making star-block copolymers

A semi-continuous process for the preparation of star-block copolymers of 25-55% by weight of monovinyl aromatic compound and 45-75% by weight of conjugated diene monomer has been developed. The process reduces the time needed to produce the copolymer by shortening reaction time and eliminating the need for costly cleanout between runs.

Growing community of inventors

West Chester, PA, United States of America

Harold L Nicholson