POLYURETHANE-AMIDE HYBRID DISPERSIONS

Aqueous polyurethanes (PU) with amide groups in hard segments were prepared by chain-extending the prepolymer with various dicarboxylic acids of adipic acid, azelaic acid, terephthalic acid and isophthalic acid and the effects were studied in terms of particle size, mechanical and dynamic mechanical properties of the cast films along with water swell and adhesion. DMTA measurements showed that adipic acid extended PU gave great soft segment-hard segment phase separation due probably to the increased cohesion of hard segments.