Synthesis of functional polyolefin copolymers with graft and block structures

This paper reviews a very useful approach in the preparation of polyolefin graft and block copolymers, containing both polyolefin block (PE, PP, s-PS, EP, etc.) and functional polymer block (acrylic and methacrylate polymers), with good control of molecular structure. The chemistry involves polyolefin 'intermediates' containing reactive borane, p-methylstyrene, and divinylbenzene units in the side chains or at the chain end, which are prepared by the combination of metallocene catalysts and reactive comonomers and chain transfer agents. The incorporated borane and p-MS groups can be transformed into 'living' radical and anion, respectively, for initiating graft-from polymerization. On the other hand, the incorporated DVB unit resembles to a styrene monomer that can involve the subsequent polymerization reactions. A broad range of polyolefin graft and block copolymers have been prepared, which have high functional (polar) group concentration without compromising the desirable polyolefin properties, such as crystallinity, melting temperature, elasticity, etc. They are very effective interfacial agents to improve compatibility of polyolefin in polymer blends and composites. (C) 2001 Elsevier Science Ltd. All rights reserved.