Improving bonding strength between a hydrophilic coating layer and poly(ethylene terephthalate) braid for preparing mechanically stable braid‐reinforced hollow fiber membranes

ABSTRACT A braid‐reinforced hollow fiber membrane with mechanically stable coating layer was prepared by coating a blended polymer dope solution on an alkaline‐treated poly(ethylene terephthalate) (PET) braid. The alkaline treatment was carried out to endow the PET braid surface with more polar groups and better hydrophilicity. The results showed that the bonding strength between the hydrophilic coating layer and modified PET braid was about two times as great as that between the coating layer and original PET braid, while the pure water permeability (PWP) of the membrane remained unchanged when the PET braid was simply treated in 3 wt % potassium hydroxide (KOH) solution at 90 °C for 1 h or 1 wt % KOH solution for 6 h. The proposed modification approach proved to be a facile, low‐cost, and effective method to improve bonding strength between the coating layer and the braid, while other properties, such as PWP and morphology of the coating layer, of the braid‐reinforced hollow fiber membranes were not altered, indicating promising potential in membrane engineering. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46104