Two methods are described for the preparation of macromonomers based predominantly on monosubstituted monomers. The first method involves the use of cobalt mediated catalytic chain transfer in copolymerizations of functional acrylic and styrene monomers with α-methylvinyl monomers to prepare macromonomers that are predominantly composed of the monosubstituted monomer. We examine the influence of the cobalt concentration, cobalt type, monomer/comonomer ratio, comonomer type, and reaction temperature on the relative amount of the desired 1,1-disubstituted alkene end group (derived from the α-methylvinyl monomer) to the 1,2-disubstituted alkene end group (derived from the monosubstituted monomer). An alternative procedure for macromonomer preparation uses no added chain transfer agent or α-methylvinyl comonomer. This procedure involves heating a mixture of the monosubstituted monomer in an appropriate solvent with an azo or peroxy initiator at temperatures between 80°C to 240°C. The effect of reaction temperature and monomer concentration on macromonomer molecular weight and the degree of branching are discussed.
|Number of pages||16|
|Journal||ACS Symposium Series|
|Publication status||Published - 1 Dec 2000|