Polymer-polymer composites fabricated by thein situ release and coalescence of polymer chains from their inclusion compounds with urea into a carrier polymer phase

Abstract

Inclusion compounds (ICs) can be formed between small-molecule hosts and guest polymers, where the crystalline host lattice confines the guest polymers to occupy narrow cylindrical channels. The included polymers are highly extended by the narrow channel diameters and are separated from neighboring polymer chains by the walls of the small-molecule host lattice. It is possible to coalesce the polymer chains from their ICs by exposure to a solvent for the small-molecule host which is not a solvent for the included polymer chains. When crystallizable polymers are coalesced from their ICs by solvent treatment, they are observed to crystallize in an extended-chain morphology accompanied by much less chain-folding than occurs when crystallization of the same polymers take place from their disordered melt or solution environments. In this report we outline our initial efforts to create polymer-polymer molecular composites based on the coalescence of polymer chains from their IC crystals with urea, which were previously embedded in a carrier polymer phase. Both film and fiber composites made with chemically identical or distinct IC-included and carrier polymers are described. Water vapor permeation, differential scanning calorimetry (DSC) and microscopic observations are used to probe these composites; and several applications are suggested. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 281–287, 1997