Accelerated UV Degradation Behavior of High Tensile Nylon 6, 6 Webbings

Abstract The paper sought to investigate the UV degradation behaviour of high tensile nylon 6, 6 webbings used in military applications. Following the military specification MIL-DTL-4088, webbings of 4 colors – navy, black, tan and white, were selected. The webbings were then subjected to a modified ASTM D2565 test standard in xenon-arc Weather-Ometer with 1.5x narrowband irradiance or 0.83 W/m2 ∙ nm at 340nm under Arizona conditions (43°C, 30% RH). SEM analysis showed no morphological changes even after 15 days of continuous exposure, contrary to literature available on degradation of nylon polymer. However, FTIR spectroscopy showed evidence of change in molecular structure of nylon webbings with increasing UV exposure duration. The finding showed that the peak at 1740cm− 1 associated with -COOH bond energy increased as exposure increased confirming hydrolysis phenomena being initiated by UV radiation. This was also confirmed by tensile test results, that showed that the strength of the webbings decreased by 20% for all color expect white webbings. The full factorial analysis showed that while exposure duration increased degradation, color of webbing also played an important role which could be the result of the dye chemistry associated with different colors. This study highlights the use of chemical characterization techniques to understand UV degradation in nylon 6, 6. Further analytical chemistry tools are necessary to quantify and correlate the chemical changes in the nylon 6, 6 webbings to breaking strength loss due to UV degradation.