Composite porous membrane for protecting high-performance fibers from ultraviolet-visible radiation

Abstract

High-strength fibers are used to produce high-strength-to-weight-ratio materials for applications such as composites, soft and hard body armor, bulletproof vests, and tendons for scientific balloons. Unfortunately, these fibers degrade when they are exposed to ultraviolet-visible (UV-vis) radiation. The objective of this research was to develop systems to improve the UV resistance of such fibers. Composite porous membranes from a polyurethane (PU) matrix loaded with rutile titanium dioxide (TiO2) nanoparticles were developed to protect a braid made of polybenzobisoxazole (PBO) yarns. The PU membranes loaded with TiO2 nanoparticles were prepared by a phase-inversion technique. The effects of the amount of TiO2 nanoparticles on the composite membrane morphological structure and UV-vis light transmission were evaluated. The results show that when the concentration of TiO2 nanoparticles was increased, the porosity of the membrane and its UV-vis blocking effectiveness increased. The UV-vis protection was evaluated by the wrapping of the PBO braid with the composite membranes and exposed to UV-vis radiation. The strength loss of the PBO fiber due to exposure was decreased from 75% for the unprotected sample to 7.8% for the protected sample in the PU loaded with 4% TiO2 nanoparticles. © 2012 Wiley Periodicals, Inc.