Tribological studies of polyamide 6 and high-density polyethylene blends filled with PTFE and copper oxide and reinforced with short glass fibers

The mechanical and tribological behaviors of polyamide 6 (PA6) and high density polyethylene (HDPE) polyblends made using maleic anhyride polypropylene as the compatibilizing agent were studied. The compositions investigated for tribological behavior were 80 wt.% PA6-20 wt.% HDPE and 60 wt.% PA6-40 wt.% HDPE. The polyblends were reinforced with glass fiber (GF) and filled with polytetrafluoroethylene (PTFE) and copper oxide (CuO). The polymeric materials were blended using a modular intermeshing co-rotating twin-screw extruder. The reinforced composite specimens with different fiber proportions were made in a reciprocating screw injection molding machine using the blended materials as the feed stock. The friction and wear experiments were run under ambient conditions in a pin-on-disk machine with the polymer pin riding on the flat surface of a steel disk at a sliding speed of 1 ms^-1 and under a nominal pressure of 0.64 MPa. The tensile strength of the polyblend with composition 80 wt.% PA6-20 wt.% HDPE increased with fiber reinforcement but the material became brittle. The maximum reductions in wear and the coefficient of friction were obtained by filling the polyblends with 10 wt.% PTFE. The fiber glass reinforcement was not found effective in lowering the already low wear rate of the polyblend.