Morphology and properties of waterborne polyurethane/clay nanocomposites

Aqueous emulsion of polyurethane ionomers, based on poly(tetramethylene glycol) or poly(butylene adipate) as soft segment, isophorone diisocyanate as diisocyanate, 1,4-butandiol as chain extender, dimethyl propionic acid as potential ionic center, triethylene tetramine as crosslinker, and triethyl amine as neutralizer., were reinforced with organoclay to give nanocomposites. The particle size of emulsion was measured and the morphology of these nanocomposites was observed by transmission electron microscope, where the effectively intercalated or exfoliated organoclay was observed. The reinforcing effects of organoclay in mechanical properties of these nanocomposites were examined by dynamic mechanical and tensile tests, and the Shore A hardness was measured. Enhanced thermal and water resistance and marginal reduction in transparency of these nanocomposites were observed compared with pristine polymer. (C) 2002 Elsevier Science Ltd. All rights reserved.