Polysilalkylene or silarylene siloxanes said hybrid silicones

This paper reviews different methods of synthesis of polysilalkylene or silarylene siloxanes that are sometimes called "hybrid" silicones. This special type of silicone has been developed to avoid the drawback of the depolymerization of classical polysiloxanes in certain conditions and to obtain elastomers with enhanced thermal and fuel resistance properties. These silicones have been prepared through two main routes: the polycondensation of alpha, omega-bis silanol monomers (prepared either via an organometallic route or via hydrosilylation of alpha, omega-dienes) and the polyhydrosilylation of alpha, omega-dienes with dihydrodisiloxanes or oligosiloxanes.