Organosilane and organopolysiloxane free radical initiators and macromonomers and graft copolymers which can be prepared with them

An organosilane or organopolysiloxane containing groups which form free radicals and consisting essentially of from 0.1% to 100.0% by weight of units of the formula

• (R.sub.a Si(O.sub.(3-a)/2) --R.sup.1 --C.sub.6 H.sub.4-x --R.sup.5.sub.x --N.dbd.N--S.sub.y --R.sup.1 --R.sup.2) (1),
• 0% to 80.0% by weight of units of the formula
• (R.sup.2.sub.3 SiO.sub.1/2) (2),
• 0% to 99.9% by weight of units of the formula
• (R.sup.2.sub.2 SiO.sub.2/2) (3)
• 0% to 80.0% by weight of units of the formula
• (R.sup.2 SiO.sub.3/2) (4)
• and
• 0% to 80.0% by weight of units of the formula
• (SiO.sub.4/2) (5),
• in which
• R is identical or different chlorine or bromine atoms, hydroxyl groups, C.sub.1 - to C.sub.18 -alkoxy radicals, or monovalent C.sub.1 - to C.sub.18 -hydrocarbon radicals which are optionally substituted by halogen atoms, amino groups, hydroxyl groups, epoxyalkyl radicals or cyano groups,
• R.sup.1 is a chemical bond, or identical or different divalent C.sub.1 - to C.sub.18 - saturated, optionally branched alkylene radical or an unsaturated alkylene radical which is optionally substituted by halogen atoms, amino groups, hydroxyl groups, acyloxy groups, epoxyalkyl radicals or cyano groups and can be interrupted by divalent radicals, bonded to carbon atoms on both sides, from the group consisting of --O--, --S--, --COO--, --OOC--, --CONR.sup.2 --, --NR.sup.2 CO--, --NR.sup.2 -- and --CO--,
• R.sup.5 is identical or different halogen atoms, cyano groups, nitro groups, or radicals --R, --OR or --C(O)R,
• R.sup.2 is a hydrogen atom or a radical R and
• a is 0, 1, 2 or 3,
• x is 0, 1, 2, 3 or 4 and
• y is0or 1, with the proviso that if 100% by weight of units of formula (I) are present, a has the value 3.