Heterogeneous Catalyzed Copolymerization of Octamethylcyclotetrasiloxane with 1,3,5,7-Tetravinyl-1,3,5,7-tetramethylcyclo-Tetrasiloxane

For the introduction of vinyl groups at the Si atom of the siloxanic chain, copolymerization of octamethylcyclotetrasioloxane (D4) with 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (V4) was performed. Vionit CS-34 C, a styrene-divinylbenzene copolymer with SO3H groups, was used as catalyst. To estimate the reactivity ratios by the Mayo-Lewis scheme, the reaction was stopped at maximum 10% conversion. The probabilities of triads existence were calculated from 29Si NMR, then the microstructure parameters of the formed copolymers were estimated. It was noticed that the dimethylsiloxy units have a higher tendency to form blocks.