Degradation study of polyester fiber in swimming pool water

The disinfection of swimming pool water is vital to maintain water quality. The chemicals used in this practice can damage the fabrics of bathing suits and shorten the shelf life of the textile substrate. The degradation of polyester, a polymer that is widely used in bathing suits for swimming pools, was investigated. For this, a 23 factorial design was employed for the experimental methodology. The effect of several variables was analyzed in a simulated swimming pool batch, such as textile-exposure time, concentration of the used disinfection product, and batch temperature. The response variables were enthalpy of fusion ΔHm, melting temperature and crystallinity (obtained by differential scanning calorimetry), percentage of weight loss, temperature of maximum rate of weight loss, onset temperature and endset temperature (measured through thermogravimetric analysis), and Young's modulus values (measured in strain-stress tests in the row and column directions). The factors of temperature, time, and the concentration of disinfectant were significant for melting temperature, crystallinity, onset temperature, and Young's modulus for columns. The analyses of variance were obtained using software Design-Expert DX7. Attenuated total reflectance-Fourier transform infrared spectroscopy analysis showed changes in band intensities at 695 cm−1, which were attributed to ester groups, as well as a decrease of the carbonyl band at 1712 cm−1, which was attributed to the hydrolysis of the material. Analysis through scanning electronic microscopy images showed the appearance of stretch marks in the constituent filaments of the tested textiles, which suggests a surface degradation occurred.