Experimental investigation of vinyl chloride polymerization at high conversion—conversion and tracer response relationships

Abstract A model for suspension polymerization which relates the conversion of vinyl chloride monomer (VCM) to polymerization conditions and a tracer response measured by online gas chromatography has been developed. This model can be used to determine monomer conversion with measurements of tracer response by gas chromatograph. A series of experiments using inert mixtures of H 2 O/PVC/VCM/ n ‐butane and using suspension polymerization of VCM with n ‐butane as tracer were carried out to evaluate the model. The solubility of n ‐butane in vinyl chloride was determined in the temperature range 40–70°C. The solubility of n ‐butane in polyvinylchloride (PVC) was estimated using nonlinear regression comparing model and experimental data for both inert mixtures and for suspension polymerization. Correlations of the solubility constants of n ‐butane in VCM and PVC, respectively, were obtained from the experimental data. Under the present experimental conditions, conversions can be measured online every 7–8 min using the n ‐butane tracer method.