Synthesis and properties of polyurethane modified with an aminoethylaminopropyl-substituted polydimethylsiloxane. II. Waterborne polyurethanes

A series of polyurethane (PU) emulsions modified with aminosilicone were sy nthesized, based on 2,4-toluene diisocyanate (TDI), poly(tetramethylene oxi de) (PTMO), and dimethylolpropionic acid (DMPA) as a prepolymer which was c hain-extended with aminoethylaminopropyl polydimethylsiloxane (AEAPS) in an aqueous emulsion. Their chemical compositions, structures, bulk and surfac e properties, and emulsion morphologies were investigated using Fourier tra nsform infrared spectrum analysis (FTIR), tensile and surface contact angle measurements, electron spectroscopy for chemical analysis (ESCA), water sw ellablity, an emulsion stability test, and transmission electron microscopy (TEM). It was shown that the PU emulsions were stable and the siloxane cha ins were enriched on the PU surface. The water resistance of the PU film in creased but the bulk tensile properties of the PU film were not changed sig nificantly with a small amount siloxane modification up to 6 wt %. (C) 2000 John Wiley & Sons, Inc.