Deterioration of polyaramid and polybenzimidazole woven fabrics after ultraviolet irradiation

摘要

In this study the degradation of woven fabrics of meta-aramid and the blend of para-aramid and polybenzimidazole fibers when exposed to environmental conditions has been investigated under accelerated ageing conditions. Generally, these polymeric materials have been used for the outer layer of protective clothing, particularly for fire-fighting. The performance of these fabrics plays an important role in preventing burn-injuries to fire fighters. Frequent exposure of these materials to various environmental conditions (especially sunlight) can degrade the polymeric chain and affect their performance properties. Hence, the degradation of the fabrics has been studied in terms of loss of tensile and tear strength; reduction in abrasion resistance; and extension at break. It was observed that ultraviolet (UV) irradiation negatively impacted on the mechanical properties of both the polymeric materials significantly. This can be attributed to chemical changes in the polymeric chains due to the photo-oxidation of the polymer. Scanning electron microscopy images revealed surface decomposition of the filaments due to UV irradiation. Exposure of polybenzimidazole resulted in rapid loss of mechanical and chemical properties in comparison with meta-aramid. However, decomposition and degradation of polybenzidimazole was not statistically significant. (C) 2015 Wiley Periodicals, Inc.