Influence of γ irradiation on the structure and tribological properties of polyphenylene sulfide

Polyphenylene sulfide (PPS) was irradiated with six different γ radiation doses to investigate its effect on the structural and tribological properties. Fourier transform infrared-atomic absorption spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results revealed that irradiation induced significant oxidation of PPS, leading to the formation of C-O, C=O, S=O, and O=S=O groups. The degree of oxidation increased with higher irradiation doses. X-ray diffraction (XRD) analysis showed that the irradiation damage to PPS primarily affected the amorphous region, where molecular chains underwent cross-linking and fracture, resulting in both cross-linked structures and shortened molecular chains. Wear tests indicated that the oxidative degradation of the material's surface due to irradiation was the main factor driving changes in the frictional properties of PPS. As the irradiation dose increased from 0 to 5 MGy, both the average friction coefficient and wear rate of PPS exhibited an upward trend. The wear mechanism of PPS samples at 0, 0.1 and 0.5 MGy was characterized by abrasive wear combined with adhesive wear, while at 1, 3 and 5 MGy, the wear mechanism included abrasive wear accompanied by material spalling.