PHASE-SEPARATION IN POLYMER-SOLUTIONS FROM A BORN-GREEN-YVON LATTICE THEORY

Phase separation in mixtures of polymers and alkanes is investigated w ith the aid of a recently developed lattice model, based on the Born-G reen-Yvon (BGY) integral equation approach to fluids. The system-depen dent parameters of the BGY lattice model for binary mixtures are deduc ed from those of its pure components, which in turn are determined fro m a comparison with experimental data. The lower critical solution tem peratures (LCSTs) for polyethylene (PE) in various n-alkanes were pred icted from the BGY lattice model and compared with experimental data. While the model underestimates the LCSTs for the smaller alkanes, it r eproduces the experimental values very well for the higher alkanes (de cane through tridecane), The effect of the chain length of the polymer on the solubility is investigated for the case of decane as a solvent . (C) 1998 Elsevier Science B.V. All rights reserved.