Thermodynamics of flow-induced phase separation in polymers. II. The effect of molecular weight distribution
Article first published online: 9 MAR 2003
Copyright © 1986 John Wiley & Sons, Inc.
Journal of Applied Polymer Science
Volume 31, Issue 2, pages 399–417, 5 February 1986
How to Cite
Vrahopoulou, E. P. and McHugh, A. J. (1986), Thermodynamics of flow-induced phase separation in polymers. II. The effect of molecular weight distribution. J. Appl. Polym. Sci., 31: 399–417. doi: 10.1002/app.1986.070310209
- Issue published online: 9 MAR 2003
- Article first published online: 9 MAR 2003
- Manuscript Accepted: 3 MAY 1985
- Manuscript Received: 26 MAR 1985
A thermodynamic analysis of flow-induced phase transformations in polymers is presented. Calculations are based on the assumption that stresses on the polymer coils lower their effective flexibility. This leads to the possibility of a spontaneous liquid separation in which the more concentrated phase contains chains having a lower flexibility relative to those in the more dilute phase. The effects of molecular weight distribution are included, and calculations demonstrate that reducing the flexibility also enhances fractionation in that the more concentrated phase is preferentially enriched with the higher molecular weight fraction of the original polydisperse system. These results offer a quantitative basis for understanding flow-induced structure formation and phase transformation phenomena in polymers in general and the phenomena of precursor formation and polymer fractionation in flow-induced crystallization in particular. Application to the latter phenomenon is also discussed.