Design of Low Wear Polymer Composites

Abstract

Multifunctional tribological coatings rely on combinations of materials to improve properties, such as lubricity and wear resistance. For example, some polymer composites exhibit favorable tribological performance as solid lubricants. Here, classical molecular dynamics simulations are used to investigate the tribological behaviors of a mixed system of polyethylene (PE) sliding over polytetrafluoroethylene (PTFE) with the results compared with the sliding of the relevant homogeneous systems. In particular, oriented cross-linked PTFE and PE surfaces are slid in several relative sliding directions such that the surface chains are in-registry or out-of-registry and at various applied normal loads. The simulation results quantify the ways in which the mixed PTFE-PE system behaves differently than either of the homogeneous systems due to the lack of interlocking phases at the interface. These findings are compared with experimental production of polyetheretherketone (PEEK)-PTFE composites that have unusually low wear rates of 7.0 9 10 -8 mm 3 /Nm, coupled with a steady, low friction coefficient of l = 0.11 for over two million sliding cycles. The simulation results explain the atomic-scale origins of the frictional properties of this composite.

Degradation of polymer films

“…[168][169][170] Numerous studies have been undertaken which concentrate mostly on numerical models and experimentation, but still there is no real consensus on what the most appropriate models to use for predicting behaviour of polymer thin lms in general. [168][169][170][171][172][173][174][175][176][177][178][179][180][181][182] One signicant reason for this is that analytical equipment such as atomic force microscope, Raman spectroscopy, interferometry and scanning electron microscopy, etc. with the resolution to measure forces and image bond energies and topologies at this scale have only recently been developed.…”

The mechanical and frictional properties of poly(ether ether ketone) composites with modified aluminum borate whiskers

“…15 However, the solid lubrications (such as nanoparticles, polytetrafluoroethylene (PTFE), graphite, and so on) application in reduction friction will lead to the deterioration of mechanical properties and decreases of the wear resistance. 16 –19…”

“…15 However, the solid lubrications (such as nanoparticles, polytetrafluoroethylene (PTFE), graphite, and so on) application in reduction friction will lead to the deterioration of mechanical properties and decreases of the wear resistance. [16][17][18][19] The performance of polymer composites depends on the interfacial bonding strength between fillers and polymer matrix; inorganic fillers are usually first treated by coupling agents before compounding to promote the dispersion and improve the interfacial adhesion with polymer matrix. A novel boric acid-containing poly(arylene ether ketone) was prepared according to the previous literatures.…”

The tribological behaviour of carbon fibre reinforced polyaryletherketones (PAEKs) through their glass transitions

“…In many systems, PAEKs are used without a liquid lubricant and in such cases a solid lubricant is also often added to the polymer to further reduce friction e.g. graphite, 11–17 PTFE, 11–14,16–21 molybdenum disulphide, 16,22 or a combination. 11,12,17 Some systems are also liquid lubricated 23–25 and, as may be expected, solid lubricants are not typically used in these situations.…”