The Effect of Nano-TiO<,2> on Ultraviolet Stability of Poly (p-phenylene Benzobisoxazole) Fiber

摘要

Poly (p-phenylene benzobisoxazole) (PBO)/titanium oxide (TiO<,2>) nanocomposites were first prepared by in-situ polymerization and the fibers had been successfully spun via dry-jet wet spinning technique. The weathering behavior of the fibers was investigated after being exposed under ultraviolet radiation for up to 100 hours. The results indicated that the pure PBO showed a large deterioration in mechanical properties, as a consequence of chemical degradation that resulted in chain scission reactions and surface deterioration. Slight content (0.3%wt) of TiO<,2> confirmed the protecting action of this additive in PBO fiber, and in the initial exposure time tensile strength droped slowly after 0.3%wt and 1.5%wt TiO2<,2> adding in polymer, also the protecting effect improveed with the content of TiO2 <,2> increased. However, from the observation of SEM image, nano-TiO<,2> facilitated surface cracking in PBO/TiO<,2> 1.5% fiber as the exposure time reached 40hr due to the anatase crystal part of TiO<,2>. Compared with the changes of tensile strength and intrinsic viscosity, it also could be concluded that surface deterioration took more important roles than macromolecule weigh decrease in the photodegradation of PBO and composites under UV exposure.