ANALYSIS OF EQUATIONS OF STATE OF POLYOLEFIN MELTS IN TERMS OF SIMHA-SOMCYNSKY HOLE THEORY

Pressure-volume-temperature data on melts of polyolefins, that have been previously reported by the author, as well as literature data have been evaluated in terms of the Simha-Somcynsky hole theory of polymeric liquids by a determination of the reducing parameters P, V, and T for each system. Agreement with theory is best for the polyethylenes and deteriorates markedly in the series PBT:PP:PMP. These higher polyolefins have very low values of P, thus suggesting a deficiency of the Simha-Somcynsky theory at high reduced pressures. Correlations found previously between T and the molecular weight M//0 of the effective segment of the theory or its hard-core volume M//0V are obeyed by the polyethylenes only. The higher polyolefins show serious deviations from these correlations.