Carboxylic acid mono functional poly(methyl methacrylate) was prepared by emulsion photopolymerization using 4-diethylthiocarbamoylsulfanylmethyl benzoic acid (DTBA) as sur-iniferter agent. DTBA is efficient to obtain mono functional polymers with a linear evolution of M-n vs. monomer conversion up to 60%. Beyond 60% monomer conversion, Mn decreases drastically and addition of a supplementary surfactant seems to disturb the effect of sur-iniferter. Secondly, an alpha-functional polymer presenting a M-n = 43500 g/mol, a polydispersity index I-p = 2.67 and a functionality f(COOH) = 98% was grafted in the molten state onto a statistical copolymer of ethylene and glycidyl methacrylate and the amount of PMMA grafts was about 10 wt%. In a final step, the graft copolymer was used as emulsifier in LDPE/PVDF blends. Blends including the graft copolymer present a better interfacial adhesion and a reduction of the size of the dispersed phase in comparison with blends without additive. (C) 2003 Elsevier Ltd. All rights reserved.