In the study, we allowed PEG and dimethyl 5-sulfoisophthalate sodium salt (SIP) to undergo transesterification to obtain PEG containing sulfonic groups (SE), then used SE and isophorone diisocyanate as soft and hard chains, respectively, and methyl ethyl ketoxime, hydroxyethyl methacrylate or 2,3-Epoxy-1-propanol as blocking reagents to synthesize three kinds of reactive urethane oligomers (MSE, HSE, and OSE). PET textiles treated by oligomers were investigated for their effects to the durable hydrophilic properties of PET fibers under different processing temperatures, time lengths, and oligomer concentrations. The results are concluded and described later: The add-on and durability of processed fabrics both were improved following the rise of processing temperature and a longer processing time. When oligomer concentration was increased, the add-on on processed textiles also increased, but their durability decreased. When PEG segment was larger, the add-on and durability both decreased. The hydrophilicity of processed textiles was proportional to the increase of oligomer concentration. The processing time was more crucial to the hydrophilic property of HSE processed textiles, but for that of MSE, the processing temperature was more important. The hydrophilic property of OSE processed textiles absolutely depended on the add-on of processed textiles. Textiles processed in oligomers of PEG molecular weight 1000 showed the highest vertical wicking height. Within these three kinds of oligomers, MSE led to the highest add-on on processed textiles and HSE textiles possessed the best of durability. OSE processed textiles possessed the best hydrophilic efficiency and electrostatic dissipating property. Textiles processed in HSE containing PEG molecular weight 1000 could have the best hydrophilic and durability. (c) 2007 Wiley Periodicals, Inc.