Phase systems of polystyrene and polyisobutylene in carbon tetrachloride

Because of the increased use of polymers in coating and lacquers, it was of interest to investigate the phase separation of polystyrene of differing molecular weight ranges and a fixed molecular weight sample of polyisobutylene with carbon tetrachloride as solvent. Three samples of polystyrene were prepared, fractioned into molecular weight ranges from 25,200 to 838,000. The polyisobutylene, of average molecular weight of 238,000, was obtained by fractionation of a commercial sample. Molecular weights were determined by viscosity measurements. Four ternary phase diagrams were determined. Several tie lines were determined for three phase systems by s modified Bancroft-Hubard method. Osmotic pressure measurements were used to determine the tie lines for the other system and for ta supplemental ternary system. The osmotic pressure method is suggested as a more suitable means of determining ties lines.