A reactive fluorine-free, efficient superhydrophobic and flame-retardant finishing agent for cotton fabrics

A novel finishing agent, N,N-dimethyl-octadecyl phosphate acrylamide (NDOPA), was synthesized with octadecanol, phosphorous acid, formaldehyde and acrylamide, and applied to cotton fabrics by ultraviolet curing to endow cotton fabrics with superhydrophobicity and flame retardancy. Results showed that NDOPA could be grafted onto cotton fabrics through C–O–C covalent bonds during the ultraviolet curing process. The contact angle of cotton fabric treated with the 10% NDOPA agent could reach 157.5°. The treated cotton fabrics exhibited clear flame retardancy. The treated cotton retained strong hydrophobicity and flame retardancy after 30 laundering cycles, indicating that the treated cotton fabrics had excellent durability. Thermogravimetric analysis revealed that the treated samples had flame-retardant properties. The results of Fourier-transform infrared spectroscopy, energy dispersive X-ray analysis and scanning electron micrography showed that NDOPA was successfully grafted onto the cotton fabrics; X-ray diffraction analysis indicated that the crystallized structure of treated cotton fibers nearly did not change. Graphical abstract