Emulsion polymerization stabilized by polymeric surfactant prepared by γ-ray radiation

A series of random copolymers with different molecular weight and composition, poly[(n-butyl methacrylate)-co-(tert-butyl methacrylate)], were prepared by reversible addition fragmentation chain transfer (RAFT) living free radical polymerization by γ-ray radiation. The alkali soluble polymeric surfactants (ASPS) obtained by both the cleavage of the tert-butyl groups in the PnBMA-co-PtBMA and directly prepared by general radical copolymerization of n-butyl methacrylate and methacrylic acid were applied in the emulsion polymerization of styrene. The effects of molecular weight, concentration of ASPS and content of carboxyl in ASPS on emulsion polymerization were studied. The final latex was characterized by transmission electron microscopy (TEM). The results indicated that the rate of polymerization increased with increasing ASPS concentration. The higher content of carboxyl in ASPS is, the higher rate of polymerization is, and the smaller particle size of final latex was obtained. In addition, micron scale latex with narrow particle distribution could be easily obtained by the emulsion polymerization stabilized by ASPS prepared by living radical polymerization process, but only latex with smaller particle size and broader distribution was obtained when ASPS was synthesized by general radical polymerization process.