MODELING SUSTAINED OSCILLATIONS IN CONTINUOUS EMULSION POLYMERIZATION OF VINYL-CHLORIDE

A simple mathematical model for the continuous emulsion polymerization of vinyl chloride based on nonlinear ordinary differential equations for the variation of particle concentration, total particle volume, and water-soluble oligomeric products was developed and used to investigate which reactions influence whether or not sustained oscillations of latex properties occur at high conversion steady state. Results of the calculations are in good qualitative agreement with experimental data. Specifically, numerical analysis showed that the occurrence of sustained oscillations depends on particle coalescence as well as on the conversion dependence of both particle volume growth rate and particle coalescence rate. The model makes it possible to calculate the dynamic behavior of continuous emulsion polymerization reactors with regard to latex properties such as particle concentration, mean particle size, latex surface tension, solid content, and degree of coverage of latex surface with emulsifier from the start-up into a high conversion steady state.