Free-radical grafting of monomers onto polymers by reactive extrusion: principles and applications

Abstract

In recent years, increasing activities have been directed towards chemical modifications of existing polymers in order to obtain functional and/or engineered new materials [1, 2]. Chemical modifications of existing polymers are important for at least two reasons: 1. they can be an inexpensive and rapid way of obtaining new polymers without having to search for new monomers¹; 2. sometimes they may be the only way to synthesise intended polymers². One of the important chemical modification methods is the free-radical grafting of reactive monomers, which involves reaction of a polymer with a vinyl-containing monomer or a mixture of monomers capable of forming grafts onto the polymer backbone. If the grafts are long, the modified polymer becomes a true graft copolymer, of which the properties will be very different from those of the original polymer substrate. When the grafts are short with less than, say, five moieties, most of the physical and/or mechanical properties of the original polymer substrate will be retained. However, the chemical properties of the modified polymer may become quite different, this often being the ultimate objective.

This Chapter is dedicated to the memory of M. Lambla who has sadly died before the completion of this book.