Mixtures of layered silicates (vermiculite and kaolinite) and carbon fibers were investigated as filler materials for polytetrafluoroethylene. The supramolecular structure and the tribological and mechanical properties of the resulting polymer composite materials were evaluated. The yield strength and compressive strength of the polymer increased by 55% and 60%, respectively, when a mixed filler was used, which was attributed to supramolecular reinforcement of the composites. In addition, the wear resistance increased by 850 times when using vermiculite/kaolinite fillers, which was due to protection of the surface by the formation of hard tribofilms.

Deficiencies in wear and frost resistance as well as mechanical strength constitute the main causes of equipment failure under the harsh climatic conditions of the Earth's polar regions. To improve the properties of the materials used in this equipment, nanoparticle composites have been prepared from clays such as kaolinite, hectorite, and montmorillonite in combination with polytetrafluoroethylene (PTFE) or ultrahigh molecular weight polyethylene (UHMWPE). A number of techniques have been proposed to disperse silicate particles in PTFE or UHMWPE polymer matrices, and several successful processes have even been widely applied. Polymer nanocomposites that exhibit enhanced mechanical and thermal properties are promising materials for replacing metals and glass in the equipment intended for Arctic use. In this article, we will review PTFE-and UHMWPE-based layered silicate nanocomposites.

No abstract

No abstract

We investigated tribological properties and worn surfaces morphology of polymer nanocomposite (PNCs) based on ultrahigh-molecular-weight polyethylene and aluminum and silicon oxide and nitride nanoparticle (NP) fillers by several methods to establish wear mechanisms. Joint mechanical activation in a planetary mill was used for the PNC preparation. PNCs with Al2O3 showed the best wear resistance. Scanning electron microscopy suggests that worn surfaces of PNCs with different fillers had different wear mechanisms. IR-spectroscopy and EDS analysis showed that oxidation processes occurred during friction and wear. Oxides of aluminum and silicon might be catalysts of oxidation processes. Due to tribochemical processes, cross-linked structures were formed on the PNCs surfaces. Probably, these cross-linked structures provide increase of wear resistance.