Degradation of Polypropylene Filament Under Elevated Temperature and High Oxygen Pressure

The oxidation degradation of a stabilized polypropylene filament was evaluated in incubation conditions that combined elevated temperature and high oxygen pressure. The incubation temperatures ranged from 45 to 105 degrees C; oxygen pressures were 1.3, 2.8, 4.9, and 6.3 MPa. The antioxidant content in the filament was measured using the high pressure oxidative induction time (HP-OIT) test. while the oxidation of the polymer was evaluated by measurement of the tensile strength. Onset of oxidation corresponded to 10% HP-OIT retained. The temperature effect on the oxidation rate obeys the Arrhenius equation; the oxidation rate is exponentially related to the pressure. Temperature and pressure were found to act independently on the oxidation of the PP filament. The service life at 25 degrees C and one atmosphere was predicted based on a master curve that was generated by applying time-temperature superposition and time-pressure superposition principles.