| abstract |
Tough gels and elastomers are prepared using compositions curable by a platinum catalyzed hydrosilation reaction that are characterized by the presence of a chain extender containing two silicon-bonded hydrogen atoms per molecule and a cross-linking agent containing at least three silicon bonded hydrogen atoms or alkenyl radicals per molecule, with the proviso that the chain extender contains at least 80 percent of the silicon bonded hydrogen atoms present in the composition or, when said cross-linking agent contains alkenyl radicals, said chain extender contains at least 80 percent of the total moles of silicon bonded hydrogen and said alkenyl radicals. |