New synthesis of photocurable silanes and polysiloxanes bearing heterocyclic or olefinic functions

In this work, we described the synthesis of silanes and polysiloxanes bearing cationic photopolymerizable groups. Two new methods were used. The first one is the reaction between 3-mercapto-propyl-1-triethoxysilane (1) and chloromethylated olefins by a phase transfer catalysis. The second one is the radical addition of (1) or poly(dimethylsiloxane-co-methylmercaptopropylsiloxane) (9) to allyl or vinyl substituted heterocyclic monomers. These methods led to the expected adducts with an excellent yield. The polysiloxanes bearing heterocyclic functional groups linked through thioether bonds were photocurable by cationic route. Under UV light intensity of 17.5 mW/cm2 , these polymers harden after 15 or 20 s