Preparation and properties of polyester fibers with polyacrylamide hydrogel grafted by UV-irradiation

It is widely recognized that polyester (PET) fibers with swelling properties are necessary for advanced applications of PET fibers in waterproof fabrics. This study presented the UV-initiated methods to graft polyacrylamide (PAM) hydrogel on the surface of PET fibers. In the one-step method, PET fibers are impregnated with a mixed solution of the photoinitiator benzophenone (BP) and the monomer acrylalkylamine (AM). Then, the PET fiber was directly exposed to UV light. In the two-step method, PET fibers were first impregnated with a photoinitiator solution to generate BP radicals. Then, the fibers impregnated with a monomer solution before being grafted by UV light. Both two methods ultimately achieve PAM gelation-modified PET fibers. The chemical composition and surface structure were detected by Fourier transform infrared spectroscopy and scanning electron microscope. The findings demonstrate that the PAM hydrogel was successfully grafted on the PET fibers through one-step method or a two-step method. In addition, the properties of the grafted PET fibers were evaluated by grafting yield, contact angle, and swelling test. The study indicated that the modified PET fibers via a two-step method exhibited a superior grafting yield up to 29.3% (PET-2n) and 54% (PET-2) compared to the one-step technique (PET-1). It was shown that the grafting efficacy of PET fibers modified by two-step method is better than one-step method. The static contact angles of PET fibers by UV-Induced were all reduced. For instance, the contact angles of PET-2n were decreased from 115 degrees to 62.9 degrees; and the two-step modified PET fiber after acetone cleaning (PET-2) decreased from 115 degrees to 60 degrees. It was suggested that the hydrophilicity of the modified PET fibers significantly increased. In addition, the research shows that the gelation-modified fibers were all possessed swelling properties.