Survey of Graft Copolymer Synthesis

2 Survey of Graft Copolymer Synthesis using Macromonomers 

Even though some techniques of cationic grafting 125) and of free-radical grafting4 have been developed 126,127), the number of systems that can actually be used is very small, and the search for new and more general methods, applicable to systems that cannot respond to ionic techniques, has been one of the determining factors for research in the field of macromonomers. 

The chief reason for the interest in graft copolymers originates from the incompatibility between polymer chains of different chemical nature. Intramolecular phase separation results, because grafts and backbone repell each other, and these compounds exhibit a marked tendency to form mesomorphic phases like block copolymers and soaps do. When these species are mixed with a solvent that exhibits a preferential affinity for one of the components (grafts or backbone) the incompatibility may be enhanced. This intramolecular phase separation has led to a number of applications. If small amounts of a graft copolymer are included into a homopolymer of the same nature as the grafts (or the backbone), surface modifications can result as described below. 

4 Grafting can also be achieved by means of high energy irradiation techniques. However, in many cases, side reactions such as cross-linking, fragmentation, and homopolymerization may also occur 

Special attention was granted to amphiphilic graft copolymers in which hydrophilic grafts are attached to a hydrophobic backbone (or vice versa). Such materials can be used as emulsifiers, compatibilizers, surface modifiers, adhesives, etc. and they may play a role in many industrial developments. 

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