Effects of NO2 gas concentration on the degradation of polyphenylene sulfide non-woven bag filter at high temperature

The influence of NO2 concentration and exposure time on the degradation of polyphenylene sulfide (PPS) fabric filter at high temperature was investigated in detail. PPS fiber damage in the filter became more severe with increasing NO2 concentration and exposure time. The elastic modulus of the PPS filter increased rapidly during the initial stage of exposure, and then increased more slowly to reach an almost constant value, nearly independent of NO2 concentration. The tensile strength also decreased significantly during the initial stage, gradually attaining a constant value with increasing exposure time. Higher NO2 concentrations resulted in rapid reducing of the tensile strength. Short exposure time to lower NO2 concentrations caused the oxidation of S atoms in PPS to SO and OSO, whereas oxidation of benzene rings in PPS were induced only with longer exposure times and higher NO2 concentrations. The model proposed in our previous paper accurately expresses the change in PPS conversion and reaction rate for every NO2 concentration. An improved model that successfully estimated the degradation of tensile strength in both the machine direction and transverse direction, regardless of NO2 concentration, was also proposed.