Ab initio reversible addition–fragmentation chain transfer emulsion polymerization of styrene/butyl acrylate mediated by poly(acrylic acid)‐block‐polystyrene trithiocarbonate

Abstract Ab initio reversible addition–fragmentation chain transfer ( RAFT ) emulsion polymerization of styrene/butyl acrylate was investigated with the trithiocarbonate macro‐ RAFT agent poly(acrylic acid)‐ block ‐polystyrene ( PAA ‐ b ‐ PS ) as a stabilizer and a RAFT agent. Influences of the amount of ammonium persulfate ( APS ), the amount of PAA ‐ b ‐ PS and the mass ratio of monomers on emulsion polymerization and film properties are discussed. The particle morphology exhibited spherical‐like structure with particles of about 90 nm in diameter and relatively narrow particle size distribution characterized using transmission electron microscopy and dynamic laser scattering. Fourier transform infrared and 1 H NMR spectra showed that the styrene/butyl acrylate emulsion was successfully synthesized. The monomer conversion increased initially with increasing amount of APS , from 0.4 up to 0.8 wt%, and then decreased. The particle size increased and its distribution decreased gradually with increasing amount of APS . The monomer conversion increased from 76.83 to 94.21% as the amount of PAA ‐ b ‐ PS increased from 3 to 4 wt%, and then decreased with further increase of PAA ‐ b ‐ PS . The particle size decreased and its distribution increased with increasing amount of PAA ‐ b ‐ PS . The water resistance and solvent resistance of the polymer films initially increased and then decreased with decreasing mass ratio of butyl acrylate to styrene. © 2014 Society of Chemical Industry