POLYMER-POLYMER COMPOSITES FABRICATED BY THE IN-SITU RELEASE AND COALESCENCE OF POLYMER-CHAINS FROM THEIR INCLUSION-COMPOUNDS WITH UREA INTO A CARRIER POLYMER PHASE

Inclusion compounds (ICs) can be formed between small-molecule hosts a nd guest polymers, where the crystalline host lattice confines the gue st polymers to occupy narrow cylindrical channels. The included polyme rs are highly extended by the narrow channel diameters and are separat ed 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 polyme rs are coalesced from their ICs by solvent treatment, they are observe d to crystallize in an extended-chain morphology accompanied by much l ess chain-folding than occurs when crystallization of the same polymer s take place from their disordered melt or solution environments. In t his report we outline our initial efforts to create polymer-polymer mo lecular composites based on the coalescence of polymer chains from the ir IC crystals with urea, which were previously embedded in a carrier polymer phase. Both film and fiber composites made with chemically ide ntical or distinct IC-included and carrier polymers are described. Wat er vapor permeation, differential scanning calorimetry (DSC) and micro scopic observations are used to probe these composites; and several ap plications are suggested. (C) 1997 John Wiley & Sons, Inc.