EFFECTS OF CONSTRAINED CHAIN CONFORMATIONS ON POLYMER-SOLUTE INTERACTIONS IN SEMICRYSTALLINE POLYMERS

The chemical potential of a solute in a solid polymer includes contributions from solute-polymer chain conformations, Flory-Huggins type interaction, and elastic energy of swelling. Presence of impermeable and rigid crystallites in such systems is expected to affect all these contributions. Theoretical calculations have been performed to check the direct effects of constrained chain conformations in the amorphous domains in semicrystalline polymers. Experimental results are used to determine Flory-Huggins coefficient and elastic modulus. From all these, the primary effects are shown to be on the entropic part of the Flory-Huggins coefficient and an increase in the elastic modulus by one or two order of magnitude. Finally, these results are used to calculate the rates of solvent-induced crystallization to show that these rates can drop to negligible values as the amount of crystals formed rises. Thus, the actual degree of crystallization can lie well below the Flory-Yoon limit. © 1990, Taylor & Francis Group, LLC. All rights reserved.