Synthesis of Polyethylene-g-polystyrene and Polyethylene-g-poly(p-methylstyrene) Graft Copolymers

Abstract

This paper describes a new method to prepare polyethylene graft copolymers, such as polyethylene-g-polystyrene and polyethylene-g-poly(p-methylstyrene), with a relatively well-controlled reaction mechanism. The chemistry involves a transformation process from the metallocene copolymerization of ethylene and p-methylstyrene to the anionic living polymerization of styrene or p-methylstyrene. The metallocene catalysis produces poly(ethylene-co-p-methylstyrene) random copolymers with molecular weight distribution (Mw/Mn) of about 2.5. The following selective metalation reaction of p-methylstyrene units in the copolymer and the subsequent anionic “living” graft-from polymerization were effective to produce polymeric side chains with well-defined structure. Both graft density and graft length can be controlled by p-methylstyrene content in the PE backbone, metalation reagent, and the quantity of monomer used in the graft-from reaction. In the bulk, the individual PE and PS segments in the graft copolymers are...