PARTITION-COEFFICIENTS OF VINYL-CHLORIDE BETWEEN PVC-LIQUID-VAPOR PHASES

The distribution of vinyl chloride monomer (VCM) in solid (unplasticized PVC), liqid (water or a 1:1 water—ethanol mixture) and vapor phases is measured under equilibrium conditions. Because VCM has only recently been found to be a carcinogen and because difficulties have been encountered in the sampling and analysis of VCM in solvents and suspended PVC particles, only very limited data are available in the literature about the partition coefficients of VCM between solid/liquid/vapor phases. The equilibrium distribution of VCM in two contacting phases (solid/water or water/vapor), is reported at different temperatures and concentrations. As the solid phase concentration increases to 100, 000 ppm, the solid/liquid partition coefficient, H, attains a value which is almost indepednent of temperature. The liquid/vapor partition coefficient, H, is independent of concentration and varies only with temperature. A 1: 1 ethanol—water mixture is used to simulate the food content inside a PVC container. When this fluid mixture is used as the liquid phase, the H value was found to be lower as compared to that for pure water. The results reported in this paper should find application in the study of VCM emission control, stripping of VCM from PVC, pollution from waste streams, and migration of VCM from PVC containers to their food contents. © 1979 The Society of Polymer Science, Japan.