Soap-free emulsion polymerization of vinyl acetate initiated by potassium persulfate-sodium bisulfite redox system in the presence of poly(vinyl alcohol) mono thiol: III

Effects of potassium persulfate(KPS) and sodium bisulfite(SBS) as redox pair initiation system on soap-free emulsion polymerization of vinyl acetate in the presence of poly (vinyl alcohol) mono thiol(PVALT) were studied. Variation of polymerization I ate, particle size, and the particle size distribution were monitored as concentration of redox initiator and PVALT, ratio of water/monomer, polymerization temperature, and stirring speed changed. Both polymerization rate and particle size were increased when concentration of KPS increased or the ratio of water/monomer decreased. The redox reaction of KPS and SBS were found to be quantitative. The polymerization rate and particle size could be changed by controlling the PVALT concentration. Increased particle size was observed when stirring speed increased or the concentration of sodium carbonate increased. But the stirring speed of 200 to 300 rpm did not induce any significant change in polymerization rate or particle size. The maximum conversion rate of polymerization was achieved at pH 7.8.