Two-fluid polymer coordination solution theory - Equation of state for pure components and its applications

A new model named polymer's two-fluid coordination thermodynamic statistic model based on Flory's cell theory coupled with local composition is proposed, The hole similar to that in the Simha-Socmcynsky hole theory is introduced and two concepts of site fraction and local site fraction in Flory's theory are replaced by coordination fraction and local coordination fraction, Quasi-chemical treatment is applied to calculate the local coordination fraction, An equation of state of pure components based on the new model is derived and the P-V-T properties of three systems [polystyrene, polypropylene and poly(1-betene)], were correlated by the new equation, The results were fine, According to the relation between segment structure of polymer and holes, we predict that if polymers are similar to each other in structure, their holes and flow properties of melts decrease with the increase of size of subgroup of polymer's segment.