Effect of SiO 2 nanoparticles and gas discharge surface modification on the mechanical lifetime of PVC-based nanocomposites

This study investigates the effects of SiO2 nanoparticle concentration and gas-discharge surface treatment on the mechanical lifetime of PVC-based nanocomposites. PVC/SiO2 composites containing 1, 3, 5, 7, and 10 vol.% SiO2 were prepared using solution casting and hot pressing. Their structural and morphological characteristics were investigated by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM). The mechanical lifetime was evaluated using the Zhurkov kinetic approach over the investigated temperature and stress ranges. Among the studied compositions, the composite containing 5 vol.% SiO2 demonstrated the highest mechanical lifetime, representing a 21.3% increase compared with neat PVC. Activation-energy analysis also revealed a higher fracture activation energy for the 5 vol.% SiO2 composite, whereas no systematic variation in the extrapolated U0 and τ0 parameters was observed with increasing SiO2 concentration. Subsequent double-sided gas-discharge treatment at 7 kV further enhanced the mechanical lifetime, with the maximum improvement obtained after 25 min of treatment. Prolonged treatment, however, caused more pronounced surface modification and a subsequent reduction in mechanical performance, which may be associated with degradation processes induced by extended discharge exposure. FTIR and AFM analyses confirmed treatment-dependent changes in the near-surface chemical environment and surface morphology. Overall 5 vol.% SiO2 and 25 min of gas-discharge treatment at 7 kV were identified as favorable conditions for improving the mechanical lifetime of the investigated PVC/SiO2 nanocomposites. Results demonstrate that combined optimization of nanofiller concentration and surface treatment can effectively enhance durability of PVC-based nanocomposite materials.