This research studied urethane oligomers, which contains the sulfonic acid group and different reactive groups. First, the transesterification of dimethyl 5-sulfoisophthalate sodium salt were performed with ethylene glycol or polyethylene glycol of different molecular weights to produce PEG soft chains possessing sulfonic acid group. Subsequently, isophorone diisocyanate used as a hard chain was connected to the two terminals of the sulfonated diols, which finally were blocked by methyl ethyl ketoxime or hydroxyethyl methacrylate or 2, 3-epoxy-1-propanol to form three kinds of aqueous reactive urethane oligomers (MSE, HSE, and OSE). The MSE oligomer had the greatest particle diameter, particle variance, and streaming current readings; the HSE oligomer, and the OSE oligomer had the second large and the smallest readings of the aforementioned measurements, respectively; whereas the contact angle and surface tension appeared with an opposite trend. Within the thermal properties of oligomer, the T-g of oligomer followed the trend: OSE < HSE < MSE; however, T-m and Delta H show an opposite tendency. With regard to the reactivity of the oligomers toward PET fabric, the add-on for the variety of oligomers was in the quantity order of MSE > HSE > OSE series, and the washing durability was rated in the order of HSE > MSE > OSE series. (c) 2007 Wiley Periodicals, Inc.