HETEROGENEOUS CATALYZED COPOLYMERIZATION OF OCTAMETHYLCYCLOTETRASILOXANE WITH 7-TETRAVINYL-1,3,5,7-TETRAMETHYLCYCLOTETRASILOXANE

For the introduction of vinyl groups at the Si atom of the siloxanic c hain, copolymerization of octamethylcyclotetrasiloxane (D-4) with 7-te travinyl-1,3,5,7-tetramethylcyclotetrasiloxane (V-4) was performed. Vi onit 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 proba bilities of triads existence were calculated from Si-29 NMR, then the microstructure parameters of the formed copolymers were estimated. It was noticed that the dimethylsiloxy units have a higher tendency to fo rm blocks.