Novel starlike Amphiphilic graft copolymers with hydrophilic poly(acrylic acid) backbone and hydrophobic poly(methyl methacrylate) side chains

The first preparation of starlike amphiphilic graft copolymers with hydrophilic backbone totally free from ester groups by atom transfer radical polymerization (ATRP) was demonstrated. Methoxymethyl acrylate (MOMA) was selected as the monomer to synthesize the backbone due to its mild acidic hydrolysis conditions. ATRP initiation groups were connected to the α-carbon of the ester groups of poly-MOMA backbone to retain ester groups on the backbone so that they can be hydrolyzed to hydrophilic carboxylic groups. Graft copolymerization of methyl methacrylate (MMA) initiated by macroinitiator in bulk with CuBr/dhbpy as catalysts gave starlike PMOMA-g-PMMA with low molecular weight distributions either at 50 or 80°C.The results show that it is a significant progress for synthesis of amphiphilic star-graft copolymers since the hydrophobic side chains can be extended to other polymer blocks and the arm number can be regulated by the multifunctional initiators.