Polymer nanocomposites with enhanced performances are becoming a trend in the current research field, overcoming the limitations of bulk polymer and meeting the demands of market and society in tribological applications. Polytetrafluoroethylene, poly(ether ether ketone) and ultrahigh molecular weight polyethylene are the most popular polymers in recent research on tribology. Current work comprehensively reviews recent advancements of polymer nanocomposites in tribology. The influence of different types of nanofiller, such as carbon-based nanofiller, silicon-based nanofiller, metal oxide nanofiller and hybrid nanofiller, on the tribological performance of thermoplastic and thermoset nanocomposites is discussed. Since the tribological properties of polymer nanocomposites are not intrinsic but are dependent on sliding conditions, direct comparison between different types of nanofiller or the same nanofiller of different morphologies and structures is not feasible. Friction and wear rate are normalized to indicate relative improvement by different fillers. Emphasis is given to the effect of nanofiller content and surface modification of nanofillers on friction, wear resistance, wear mechanism and transfer film formation of its nanocomposites. Limitations from the previous works are addressed and future research on tribology of polymer nanocomposites is proposed.

Regenerated cellulose (RC)/ poly(3-hydroxybutyrate) (PHB) composite was prepared via melt compounding with different RC contents from 1 to 7 wt.%. Regenerated cellulose fiber was prepared in NaOH/urea aqueous solution. The properties of the cellulose and the regenerated cellulose were compared using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). The results of TGA and DSC revealed that the regenerated cellulose had lower thermal properties than cellulose. Meanwhile, the FTIR of regenerated cellulose showed that the intensity portrayed by a few peaks had reduced or disappeared as compared to cellulose. Besides, PHB composites were characterized using TGA and flexural testing. Moreover, thermal stability of the composites insignificantly changed with the incorporation of RC. Improvement in flexural strength and modulus were observed, whereas 3 wt.% was found to be the optimum RC content.