ORGANOPOLYSILOXANES CONTAINING AN UNSATURATED GROUP

摘要

The invention provides a composition comprising a diene elastomer and a polyorganosiloxane in which at least 50 mole % of the siloxane units are D units as herein defined and which contains at least one unsaturated group, characterized in that the unsaturated group is group of the formula -X-CH=CH-R" (I) or -X-C=C-R" (II), in which X represents a divalent organic linkage having an electron withdrawing effect with respect to the -CH=CH- or -C=C- bond and/or containing an aromatic ring or a further olefinic double bond or acetylenic unsaturation, the aromatic ring or the further olefinic double bond or acetylenic unsaturation being conjugated with the olefinic unsaturation of -X-CH=CH-R" or with the acetylenic unsaturation of -X-C=C-R", and R" represents hydrogen or a group having an electron withdrawing effect or any other activation effect with respect to the - CH=CH- or -C=C- bond. We have found that such a polyorganosiloxane containing unsaturated groups grafts readily to a diene elastomer. Such a blend has enhanced stability and mechanical properties.