Materials science and engineering are essential for advancing energy-efficient
mechanical systems through lightweight structures and friction reduction. Among
engineering polymers, polyphthalamides (PPA) are widely used for their superior
thermochemical and mechanical properties. This study investigates the influence
of polytetrafluoroethylene (PTFE) on the mechanical and tribological performance
of a commercial polymer matrix composite (PMC) reinforced with 30wt% glass
fiber. Self-lubricating composites were manufactured by injection molding with
PTFE contents ranging from 0-15 wt%. Density was measured using Archimedes’
method. Mechanical properties were measured through ISO 527 tensile testing,
while tribological behavior was evaluated using ball-on-flat reciprocating tests
under 189N (630 MPa), 2 H frequency, and 10 mm strokes for 60 minutes, employing
a 10 mm diameter AISI 52100 steel sphere as counter-body. Friction coefficient
(COF) was monitored throughout testing, and wear mechanisms were investigated
using white-light interferometry (WLI), scanning electron microscopy (SEM), and
energy-dispersive X-ray spectroscopy (EDS). Wear volumes were obtained from
contact profilometry. Results show that PTFE addition reduced mechanical
strength decreasing by 7.9%, 8.5% and 14.8% for 2%, 5% and 15% PTFE,
respectively. In contrast, tribological performance improved, with COF
stabilizing between 0.03-0.08 and wear rate decreasing from 5.6 ×
10-4 mm3/N.m (no lubricant) to 1.0 × 10-4
mm3/N.m for 2 and 5% PTFE. At 15% PTFE, wear rate and COP
increased to 2.3 × 10-4 mm3/N.m and 0.08, respectively.
EDS analysis detected fluorine on the wear surfaces, confirming the formation of
PTFE-rich tribolayers. However, excessive PTFE compromises mechanical integrity
due to the formation of large reservoirs, leading to increased deformation and
wear under high pressure. Thus, optimal performance results from balancing PTFE
content and mechanical in robustness.