A sulfur-free poly alkyl(meth)acrylate copolymer having a sulfur content of less than 50 ppm and a weight average molecular weight (M w ) of 10,000 to 200,000 g/mol and obtainable by radical polymerization of a monomer composition comprising: (a) 10 to 50 wt.-% of a polybutadiene-based macromonomer having a number average molecular weight of 500 to 10,000 g/mol, or a mixture thereof; (b) 10 to 90 wt.-% of a monomer selected from linear or branched C 1 -C 6 alkyl(meth)acrylates, styrene, substituted styrene having an alkyl substituent in the side chain and having from 8 to 17 carbon atoms, or a mixture thereof; and (c) 0 to 30 wt.-% of a monomer selected from linear or branched C 7 -C 30 alkyl(meth)acrylates, or a mixture thereof; respectively based on the total weight of the monomer composition, and. wherein the radical polymerization of the monomer composition is carried out in the presence of a sulfur-free chain transfer agent selected from: (i) terpenoids; (ii) oligomers of methacrylate or methacrylic acid having a weight average molecular weight (M w ) of less than 15,000 g/mol; (iii) styrene oligomers having a weight average molecular weight (M w ) of less than 1,000 g/mol; (iv) Co(ll) complexes; (v) addition-fragmentation chain transfer agents represented by a chemical formula (I), wherein A is -O- or -CH 2 -, X is C 1 -C 4 alkyl, peroxy C 1 -C 6 alkyl, peroxy C 6 -C 10 aralkyl, -CH 2 Ph, or -COOR 1 with R 1 being C 1 -C 4 alkyl, and Z is Ph, -CN, -OR 1 with R 1 being C 1 -C 4 alkyl, COOR 1 with R 1 being C 1 -C 4 alkyl, or-CONH 2 ; (vi) quinones; (vii) ethylenically unsaturated hydrocarbons having 4-14 carbon atoms; (viii) isopropanol; or a mixture thereof. (a) 10 to 50 wt.-% of a polybutadiene-based macromonomer having a number average molecular weight of 500 to 10,000 g/mol, or a mixture thereof; (b) 10 to 90 wt.-% of a monomer selected from linear or branched C 1 -C 6 alkyl(meth)acrylates, styrene, substituted styrene having an alkyl substituent in the side chain and having from 8 to 17 carbon atoms, or a mixture thereof; and (c) 0 to 30 wt.-% of a monomer selected from linear or branched C 7 -C 30 alkyl(meth)acrylates, or a mixture thereof; respectively based on the total weight of the monomer composition, and. wherein the radical polymerization of the monomer composition is carried out in the presence of a sulfur-free chain transfer agent selected from: (i) terpenoids; (ii) oligomers of methacrylate or methacrylic acid having a weight average molecular weight (M w ) of less than 15,000 g/mol; (iii) styrene oligomers having a weight average molecular weight (M w ) of less than 1,000 g/mol; (iv) Co(ll) complexes; (v) addition-fragmentation chain transfer agents represented by a chemical formula (I), wherein A is -O- or -CH 2 -, X is C 1 -C 4 alkyl, peroxy C 1 -C 6 alkyl, peroxy C 6 -C 10 aralkyl, -CH 2 Ph, or -COOR 1 with R 1 being C 1 -C 4 alkyl, and Z is Ph, -CN, -OR 1 with R 1 being C 1 -C 4 alkyl, COOR 1 with R 1 being C 1 -C 4 alkyl, or-CONH 2 ; (vi) quinones; (vii) ethylenically unsaturated hydrocarbons having 4-14 carbon atoms; (viii) isopropanol; (i) terpenoids; (ii) oligomers of methacrylate or methacrylic acid having a weight average molecular weight (M w ) of less than 15,000 g/mol; (iii) styrene oligomers having a weight average molecular weight (M w ) of less than 1,000 g/mol; (iv) Co(ll) complexes; (v) addition-fragmentation chain transfer agents represented by a chemical formula (I), wherein A is -O- or -CH 2 -, X is C 1 -C 4 alkyl, peroxy C 1 -C 6 alkyl, peroxy C 6 -C 10 aralkyl, -CH 2 Ph, or -COOR 1 with R 1 being C 1 -C 4 alkyl, and Z is Ph, -CN, -OR 1 with R 1 being C 1 -C 4 alkyl, COOR 1 with R 1 being C 1 -C 4 alkyl, or-CONH 2 ; (vi) quinones; (vii) ethylenically unsaturated hydrocarbons having 4-14 carbon atoms; (viii) isopropanol; <EOS>