EMULSION COPOLYMERIZATION OF VINYL-ACETATE IN PRESENCE OF ACID COMONOMERS

The interaction of acid comonomers, crotonic acid, maleic monoesters, maleic acid with the surfactant, the sodium salt of sulfosuccinic acid semiester with nonyl phenol etoxylated with 25 moles ethylene oxide ( NPEO(25)SS) depends on the hydrophilicity of comonomers. The rate of i nitiator splitting reaction (potassium persulfate - KPS) in presence o f NPEO(25)SS and of comonomers decreases with the increasing of acid c omonomer concentration This rule is valid in copolymerization of acid comonomers with vinyl acetate (VAc) below a small comonomer concentrat ion, then the rate increases. The presence of some more hydrophobic co monomers maleic diesters, lowers the decomposition rate of KPS. These results are the effect of the stronger interaction of NPEO(25)SS with more hydrophobic polymer particles. In their presence the concentratio n of free NPEO(25)SS is lower and it can participate in the KPS - surf actant reaction and rise its rate to a lesser extent. Owing to some se condary acid comonomer - KPS reactions the productivity of initiator s plitting decreases with acid comonomer concentration. The glass transi tion temperatures of the thin films obtained in presence of acid comon omers, may increase or decrease, depending on the volume of the substi tuents of these comonomers.