John C. Falk

Anionic Graft Copolymers. I. Vinylaromatic Grafts on Polydienes

Abstract Lithiated polydienes were readily prepared by direct metalation of the diene polymers with sec-butyllithium and tetramethylethylenediamine in cyclohexane at room temperature. Reaction of the polylithiodienes with styrene or a-methylstyrene formed graft copolymers. Poly-1, 4-butadiene, poly-1, 2-butadiene, cis-poly-1, 4-butadiene, and polyisoprene were the substrates lithiated. The extent of metalation was much greater than previously reported metalations with n-butyllithium and terramethylethylenediamine. The grafting efficiencies, determined by acetone extraction and gel permeation chromatography, were greater than 95%. The physical properties of the graft copolymers are compared as a function of molecular weight, graft site level, and composition. At certain molecular weights, graft site level, and compositions, elastomers are formed without vulcanization. Their properties are comparable to SBS rubber and offer higher melt flow as an advantage.

Anionic Graft Copolymers. ll. Styrene Grafts on EPT Rubbers

Abstract Rubbers containing a low level of unsaturation such as EPT may be metalated with a chelate made from s-butyllithium and N,N,N′- N′ -tetramethylethylethylenediamine. The lithiated polymers, reacted with styrene, result in polystyrene graft copolymers. The physical properties are affected by graft level and polystyrene content.

Anionic Graft Copolymers. III. Hydrogenation of Polydienes Grafted with Vinylaromatics

Abstract A new method is described to prepare graft copolymers of polystyrene and polyvinylcyclohexane on polyethylene and poly (ethylene, butene-1). Hydrogenation of the butadiene moieties of graft copolymers of polystyrene on poly-1, 4-butadiene and high vinyl polybutadiene forms graft copolymers of polystyrene on polyethylene and on poly (ethylene, butene-1). Graft copolymers of polyvinylcyclohexane on polyethylene and on poly (ethylene, butene-1) are prepared by completely hydrogenating graft copolymers of polystyrene on poly-1, 4-butadiene and on high vinyl polybutadiene. The physical properties of these polymer systems depend on composition and graft level, resulting in either tough polymers or elastomers.