Tribological performance analysis of sustainable basalt micro-filler loaded bio-based polypropylene and high density polyethylene composites

The current research work involves the fabrication and tribological properties analysis of constant basalt filler reinforced (30 wt %) bio-based polypropylene (PP) and high density polyethylene (HDPE) thermoplastic composites. Compression molding technique is used after an internal mixing process in order to produce composite samples. The physical and hardness properties have been evaluated for both neat polymers and composite samples. In order to study the coefficient of friction (COF) and specific wear rate (SWR) of PP and HDPE composite samples, the Taguchi and Analysis of Variance (ANOVA) methodologies were applied. For PP samples, the optimum parameters in response to COF are found to be 0 wt% basalt (rank 3), 9 N load (rank 1), 200 r/min speed (rank 4), and 100 m distance (rank 2); for the SWR output, the optimum parameters are 30 wt% basalt (rank 1), 6 N load (rank 4), 100 r/min speed (rank 2), and 200 m distance (rank 3). For HDPE samples, the optimum parameters in response to COF are 0 wt% basalt (rank 1), 6 N load (rank 3), 100 r/min speed (rank 4), and 100 m distance (rank 2); for the SWR output, the optimum parameters are 30 wt% basalt (rank 1), 6 N load (rank 3), 100 r/min speed (rank 4), and 150 m distance (rank 2). Consistently, it has been shown that incorporating basalt fillers to PP and HDPE composites has more dramatically decreased SWR than COF. The depth of wear constantly rises according to increasing load, irrespective of the processing variables, as shown in 2D depth profiles. It is discovered that the confirmation tests carried out for the optimum parameters are within statistically acceptable bounds. The depth profile plots revealed that the worn track edges are found with polymer bumps because of deep grooves and softened polymer debris, which commonly observed more with HDPE samples due to low softening temperature. Moreover, the worn surfaces of the composites have plowed lines and cracks that are brought about by the micro-cutting and micro-plowing activity of the erosive asperities counterface. In addition to surface characteristics, the transfer films created during sliding also significantly influenced the mode of sample wear.