Morphological Changes in Polyesters and Polyamides Induced by Blending with Small Concentrations of Polymer Diluents

Abstract

Unexpected morphological changes have been found in a number of aliphatic polyesters (poly(є-caprolactone) and the suberate, azelate, and sebacate polyesters of ethylene glycol) upon blending with small concentrations (~1%) of compatible polar polymeric diluents, notably poly(vinyl butyral) and poly(vinyl chloride). Among these changes are striking reduction in frequency of nucleation of spherulites, marked enhancement in regularity of lamellar organization in banded spherulites (also manifested by improved regularity of banding), modification of interlamellar spacings, and, in some instances, modification of molecular packing in crystals. It is believed that adsorption of diluent on crystal boundaries (growth faces and fold surfaces of lamellae) underlies most of these effects. Preliminary experiments indicate that similar morphological changes may occur in nylon 66 and nylon 610 when blended with poly(vinylpyrrolidone). © 1989, American Chemical Society. All rights reserved.