PHASE-SEPARATION OF COPOLYURETHANES - A STUDY OF ANNEALING AND SLOW SOLVENT EVAPORATION METHODS BY FTIR

Copolyether-urethane-ureas based on methylene bis(4-phenylisocyanate), polypropylene glycol (or polytetramethylene glycol), and ethylene dia mine showed improvement in packing order within the already present ph ases when subject to both thermal annealing and slow solvent evaporati on techniques using glass as the casting substrate. However, formation of these copolymer films directly onto IR salt crystals led to major disturbances in the copolymer morphology due to the dissolving of inor ganic salt into the polymer casting solution. These disturbances appea r to be caused by a salt-urea segment interaction. The urea amide I ba nd (1635 cm(-1)) appears to be a sensitive indicator of such changes i n these copolymers. (C) 1995 John Wiley and Sons, Inc.