Polycarbosilanes containing siloxy and/or silanamine units by polycondensation using hydrosilylation

Poly(1,1‐dimethyl‐1‐silylethylene): ‐(SiMe 2 ‐CH 2 ‐CH 2 )‐ n was prepared by polycondensation of HSiMe 2 ‐CH 2 ‐CH 2 ‐SiHMe 2 ( A ) with CH 2 =CH‐SiMe 2 ‐CH 2 ‐CH 2 ‐SiMe 2 ‐CH=CH 2 ( B ) under suitable hydrosilylation conditions. Functional oligomers with either two SiH or two Si‐CH=CH 2 end groups were obtained by using an excess of A or B respectively. These bifunctional oligomers were used as precursors for the preparation of well‐defined networks by reaction with different tetrafunctional crosslinking agents such as D 4 H, D 4 Vi b) and tetravinylsilane (TVS). They were also used for the preparation of multiblock copolymers by reaction with dimethylsiloxane oligomers. Alternating copolymers were obtained from monomers containing siloxy or silanamine units. Thermal properties of these polymeric materials are presented.