UV photo‐stabilization of tetrabutyl titanate for aramid fibers via sol–gel surface modification

Tetrabutyl titanate was used as sol–gel precursor of a nanosized TiO2 coating to improve the photo‐stability of aramid fibers. The nanosized TiO2 coating was characterized by XRD and XPS. The influence of the TiO2 coating on photo‐stability of aramid fibers was investigated by an accelerated photo‐ageing method. The photo‐stability of aramid fiber showed obvious improvement after coating. After 156 h of UV exposure, the coated fibers showed less deterioration in mechanical properties with the retained tensile strength and elongation at break greater than 36 and 50% of the original values, respectively, whereas the uncoated fibers degraded completely and became powdery. SEM analysis showed no significant surface morphological change on the coated fiber after the exposure, while some latitudinal crack fractures appeared on the uncoated aramid fiber. The effect of the nanosized TiO2 coating was also well demonstrated by examining the difference of distributions of C1s in XPS deconvolution analysis on the surface of uncoated/coated fibers with increasing UV exposure time.