Functionalized nanoparticles

A functionalized nanoparticle comprising on the surface a covalently bound radical of the formula I

• wherein
• the nanoparticle is a SiO2, Al2O3 or mixed SiO2 and Al2O3 nanoparticle,
• X is oxygen, sulfur or
• R1 is C1-C25alkyl, C3-C25alkyl which is interrupted by oxygen, sulfur or
• hydroxyl-substituted C2-C24alkyl which is interrupted by oxygen, sulfur or
• C2-C24alkenyl, C5-C12cycloalkyl, C5-C12cycloalkenyl, a polymerizable group, a polymer, or an additive selected from the group consisting of radical scavengers, hydroperoxide decomposers, UV-absorbers, light stabilizers, flame retardants and photoinitiators;
• R2 and R3 independently of each other are hydrogen, C1-C25alkyl, C3-C25alkyl which is interrupted by oxygen or sulfur;
• C2-C24alkenyl, phenyl, C7-C9phenylalkyl, —OR5,
• R4 is hydrogen, C1-C25alkyl or C3-C25alkyl which is interrupted by oxygen or sulfur;
• R5 is hydrogen, C1-C25alkyl, C3-C25alkyl which is interrupted by oxygen or sulfur;
• C2-C24alkenyl, phenyl, C7-C9phenylalkyl,
• or the nanoparticle surface,
• R6 and R7 independently of each other are hydrogen, C1-C25alkyl, C3-C25alkyl which is interrupted by oxygen or sulfur;
• C2-C24alkenyl, phenyl, C7-C9phenylalkyl or —OR5,
• R8, R9 and R10 independently of each other are hydrogen, C1-C25alkyl, C3-C25alkyl which is interrupted by oxygen or sulfur;
• C2-C24alkenyl, phenyl or C7-C9phenylalkyl, and
• n is 1, 2, 3, 4, 5, 6, 7 or 8.