| abstract |
The invention relates to crosslinked organopolysiloxanes which contain groups which form free radicals and are built up from units of the formula n n [R.sub.a Si(O.sub.(3-a)/2)-R.sup.1 -X-(R.sup.1 -Si(O.sub.(3-a)/2)).sub.b n n R a ] (1), n in which n X is a radical from the group consisting of --N═N--, --O--O--, --S--S-- and --C(C 6 H 5 ) 2 --C(C 6 H 5 ) 2 --, and n R is monovalent SiC-bonded, optionally substituted C 1 - to C 18 -hydrocarbon radicals, n R 1 is divalent SiC-bonded, optionally substituted C 1 - to C 18 -hydrocarbon radicals which can be interrupted by divalent radicals, bonded to carbon atoms on both sides, from the group consisting of --O--, --COO--, --OOC--, --CONR 2 --, --NR 2 CO-- and --CO--, n R 2 is a hydrogen atom or a radical R, n a has the values 0, 1 or 2 and n b has the values 0 or 1, n and further organosiloxane units. The organopolysiloxanes are used as free radical macroinitiators for grafting polymerization of ethylenically unsaturated monomers. |