The effect of initiator system on acrylate emulsion copolymerization with higher hydroxyl monomer content

The influence of the initiator (ammonium persulfate, APS) and APS/reducer system on the acrylate emulsion copolymerization of methyl methacrylate/butyl acrylate/acrylic acid/hydroxylethyl methacrylate (HEMA) was studied. The initiator level, reaction temperature, reducer type and reducer level on the effect of polymerization rate, particle size and size distribution were investigated. It was found that with the existence of hydrophilic monomer HEMA, polymerization rate increased but the particle size decreased and the size distribution became narrowed with the increase of initiator level, reaction temperature and reducer sodium hydrogen carbonate (NaHSO3) level. The APS/NaHSO3 system had better initiation efficiency than the APS/FeSO4 system. Copyright © 2006 John Wiley & Sons, Ltd.