Emulsion polymerization of vinyl acetate initiated by intermittent γ radiation

摘要

AbstractThe reaction kinetics of emulsion polymerization of vinyl acetate (VAc) monomer have been studied by using intermittent γ radiation. The purpose of this technique is to take advantage of the poly merization reaction which still continues after the radiation production has been stopped, as expected by the Smith–Ewart rate theory. Tween 20 (polyoxyethylene sorbitan monolaurate), was used as the emulsifier. The polymer conversion was determined by using the dilatometric method. The polymerization rateRpdecreased with increase in emulsifier content. The Smith–Ewart rate theory cannot explain the experimental evidence satisfactorily. The average polymerization rateRpbetween 20 and 80 conversion is a function of irradiation dose rate and can be written$$ overline {R_p } = a_1 I^{a_2 } $$wherea1anda2is a constant in which the value depends on the emulsifier content in the emulsion andIis the irradiation dose