Study on wear and friction behavior of graphite flake-filled PTFE composites

Effect of glass fibers length on the properties of polytetrafluoroethylene composites reinforced by glass fibers and graphite: Experimental and simulation study

Polytetrafluoroethylene (PTFE)-based matrix composites filled with glass fibers (GF) and graphite (GR) were prepared by an internal mixer and molded using a compression mold to produce test samples. The objective was to study the mechanical and tribological properties of PTFE composites filled with different lengths of GF. The fillers of GR and GF were 5 and 15 wt.%, respectively, with the lengths of the GF of 15, 20, 25, 30, and 35-μm in the work. The mechanical performance tests and tribological tests were carried out under the same conditions. The experimental results revealed that the mechanical properties and tribological properties of the PTFE composites filled with GF and GR were associated with the lengths of GF. When the length of GF increased from 15 to 20 μm, GF could be homogeneously dispersed in the PTFE-based matrix composites and the tensile strength reached the maximum value of 21.68 MPa. Also, with 20-μm long GF, the composites exhibited the lowest coefficient of friction values and wear rates compared to PTFE with GF of the other lengths. The changes in frictional heat generation and frictional force of the composites during sliding friction were simulated using the finite element method. The theoretical simulation results matched with the experimental values, which proved the accuracy of the theoretical simulations.

Fabrication of high-performance polytetrafluoroethylene microporous membranes filled with nano-alumina

In this article, polytetrafluoroethylene (PTFE) microporous membranes with excellent tensile strength and good wear durability were successfully fabricated by the addition of nano-alumina (Al2O3). The friction and mechanical behavior of PTFE microporous membranes with different nano-Al2O3 contents were investigated by Martindale abrasion tester, dynamic mechanical analysis, and universal testing machine. Scanning electron microscopy was applied to analyze the surface, longitudinal section, and worn surface of the microporous membranes. Results demonstrated that nano-Al2O3 particles were dispersed into the “node” structures of PTFE microporous membranes and acted as the skeleton, leading to the increasing of the tensile strength remarkably. The wear rate reduced significantly with the addition of nano-Al2O3 and was affected by nano-Al2O3 content. Additionally, the wear mechanism of the microporous membranes was also discussed based on the study results.

Polymer composites prepared by low-temperature post-irradiation polymerization of C2F4 in the presence of graphene-like material: synthesis and characterization

Study of PTFE–microwave exfoliated graphene oxide (MEGO) composites synthesized using a low temperature post-irradiation polymerization technique. SEM images of MEGO (left) and PTFE–MEGO composite (right).