Progress report - ESR 8: Maksim Nikonovich

date: May 12, 2022

category: News

Experimental and numerical study of low-wear reinforced self-lubricating polymers

The shift to eco-friendly energy sources, including hydrogen, introduces new requirements to be fulfilled by the new materials. Being unexposed to hydrogen embrittlement, polymers are expected to perform better, than metals in long-term period. During last year, the mechanical and thermal properties of the selected commercial materials based on PEEK, PI and PA46 polymers were studied. Thermal tests include thermal expansion coefficient measurements (CTE) as well as differential scanning calorimetry (DSC). DSC helped to understand the main thermal parameters of the polymers and reveal some polymer additives, which were not mentioned by the manufacturer. CTE tests proved the expected thermal stability of the materials with higher melting point and/or reinforced with carbon fibres. The mechanical tests include fracture toughness measurements and compressions. Fracture toughness tests were conducted in air at room and cryogenic temperature at -100oC. The mechanisms responsible for the material fracture were found to be dependent on the ambient temperature, the matrix nature, and the composition. The brittle fracture was observed for major polymer composites at low temperatures, whilst some grades remained brittle fracture even at room temperature. Based on compression tests the Young’s modulus, the yield and maximum compressive strength were calculated. Expectedly, the results correlated to the fracture toughness data. The composites reinforced with carbon fibres tend to have higher stiffness and toughness.  Based on the results the best composites were selected for further tribological tests in ball-on-disk configuration, and aging in liquid nitrogen.