Experimental Investigations on Nanomechanical, Tribological, and Electrical Properties of TiO₂/Polyimide-Based Nanocomposites Fabricated by SPS Technique

In this study, TiO₂ reinforced polyimide nanocomposites were successfully fabricated at varying TiO₂ nanoparticles concentrations via spark plasma sintering process. The morphology of the samples were characterized by scanning electron microscopy (SEM). The nanomechanical, tribological, and dielectric/electrical properties of the sintered samples was examined using nanoindentation tester, tribometer, and LCR meter equipment, respectively. The SEM results indicate that the TiO₂ nanofillers were equally diffused into polyimide matrix without agglomeration, hence the better interfacial bonding between the matrix and the nanofillers. Result shows that the hardness and elastic modulus of TiO₂/polyimide composite sample with 6wt% TiO₂ addition was improved by 179.3 and 76.4%, respectively, meanwhile, further addition of the nanoparticles above 6wt%, 314% improvement in hardness and 59.5% improvement in modulus was recorded compared to that of the pristine polyimide (PI). The reason for the decrease in modulus beyond 6wt% was the dosage contents of TiO₂ particles and poor stress transfer within the nanocomposites with 8wt% TiO₂ particles as elastic properties of composites depends on load transfer mechanism. In addition, the tribology and insulation performances of the virgin PI were also improved with the introduction of the TiO₂ nanoparticles. Finally, the results indicate the cost-effective measure of fabricating PI nanocomposites and its potential for mechanical loadbearing, anti-wear, and insulation applications.