Abstract: The copolymer latex of MMA-BA-HEMA-DMAEMA was prepared in the batch and semi-continuous emulsion copolymerization process. The effects of emulsifier type and concentration, polymerization temperature and the feeding rate of emulsified monomer on the stability of polymerization were studied systematically. The results show that the HLB is not critical parameter for selecting the emulsifier used for the emulsion polymerization containing water-soluble monomers. The available method for determining emulsifier system is still directly by the stability observation of the polymerization runs. The increase of functional monomer HEMA and DMAEMA content is beneficial to polymerization stability. The decrease of the polymerization temperature and the reduction of the feeding rate of the emulsified monomers are favorable to the stability of polymerization. The stability of batch polymerization is inferior to that of semi-continuous polymerization for this system. The results also show that the increase of the emulsifier concentration will improve the stability of polymerization and uniformerize the particle size.

Key words: Water-soluble monomer, Emulsion copolymerization, Polymerization stability, Coagulation ratio