FRACTAL DIMENSIONALITY OF VINYL-CHLORIDE MONOMER ADSORPTION ON POLYVINYL-CHLORIDE PARTICLES

The extent of adsorption of vinyl chloride monomer (VCM) on polyvinyl chloride (PVC) beads of various size was examined using the inverse ga s chromatography technique at 288, 295, 303, and 313 K. The sizes of t he PVC beads were 60-80, 100-120, and 150-200 mesh. On them the specif ic retention volume V-g(ml/g) of the injected gaseous monomer was dete rmined. V-g depends on the mean particle size (d) over bar of PVC bead s according to the relationship log V-g = (D - 3)log (d) over bar, fro m which the mass fractal D values were determined between 2.95 and 2.6 3 depending on the temperature and the dilution of monomer. Higher tem peratures (313 K) are associated with lower D values (2.63-2.67), wher eas lower temperatures (288 K) are associated with higher D values (2. 87-2.95). These results suggest that the PVC behaves more as a two-dim ensional material in relation to VCM adsorption at higher temperatures , whereas at lower temperatures it looks more like a three-dimensional Euclidean solid. (C) 1997 Academic Press.