The Constant Copolymer Composition Technique

The Constant Copolymer Compositon (CCC) technique readily produces copolymers with constant (homogeneous) macro-and microcompositions (microstructures) even from monomer pairs with significantly different reactivities, for example with monomers whose reactivity ratios differ by an order of magnitude. The CCC technique eliminates the compositional drift along copolymer chains which always arise in copolymers made by batch or forced ideal techniques and necessarily lead to inhomogeneous often ill-defined products. In the CCC technique a stream of comonomers is fed continuously to the active copolymerization charge such that the composition of the feed and the rate of feed addition are respectively equal to the composition of the copolymer produced and the rate of copolymerization. The fundamentals of the CCC technique together with a detailed quantitative analysis are presented, and the differences of the conventional and CCC techniques are discussed and illustrated with the industrially important isobutylene-p-methylstyrene copolymerization system.