Identifying differences in the tribological performance of GUR 1020 and GUR 1050 UHMWPE resins associated to pressure × velocity conditions in linear reciprocating sliding tests

• Published in: Journal of the mechanical behavior of biomedical materials Vol. 145; p. 106038
• Main Authors: Kapps, Vanessa, Maru, Marcia Marie, Kuznetsov, Oleksii, Achete, Carlos Alberto
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.09.2023
• Subjects: GUR 1050 and GUR 1020; Materials Testing; Polyethylenes - chemistry; Pressure-velocity; Reciprocating test; Scatter; Stability; Surface Properties; UHMWPE; Reciprocating test; Stability; GUR 1050 and GUR 1020; UHMWPE; Scatter; Pressure-velocity
• ISSN: 1751-6161; 1878-0180; 1878-0180
• DOI: 10.1016/j.jmbbm.2023.106038

In this work, two commercial UHMWPE (ultra-high molecular weight polyethylene) resins used in orthopedics, GUR 1050 and GUR 1020, were evaluated through linear reciprocating dry friction tests. Average contact pressures (P) of 34 MPa and 50 MPa and sliding velocities (V) of 0.02 m/s and 0.10 m/s were selected to perform tests in four PV conditions. The friction coefficient (COF) with both resins was around 0.18 in average, without significant distinctions by PV; however, a distinction was seen in COF dispersion; it was in the range of 5%–19%, in dependence of the PV condition and resin type. COF with GUR 1020 was more disperse, and it was related to the vulnerability of the resin to undergoing dynamic changes in the intensity of adhesive (higher COF) or abrasive (lower COF) wear mechanisms. Both wear mechanisms are displayed simultaneously, but random changes in intensity may occur during the friction process. Such randomness was associated to the susceptibility to have the structure modified by friction, higher in GUR 1020 than GUR 1050. Concerning wear amount, contact pressure was the most influencing parameter on it. GUR 1020 performed more than 30% inferior than GUR 1050 under contact pressure higher than the yield strength of the material. Under pressures near the material strength, the wear level was in the range of surface roughness and both resins performed equal in average; however, in this case, the dispersion was systematically lower for GUR 1050, evidencing its better tribological stability. It was concluded that analyses on the dispersion of the tribological responses disclosed relevant information on stability related performance. Also, when procedural dependent properties, as such friction and wear, are considered as evaluation parameters, care must be taken to compare results from different tribosystems. •UHMWPE GUR1020 and GUR1050 were compared regarding tribological performance under linear reciprocating dry ball-on-plate.•Experiments performed at four pressure-velocity levels, revealed that pressure was the most influencing test parameter.•Friction and wear volume were analyzed considering dispersion values. Dispersion was associated with stability performance.•GUR1020 friction was more unstable, lower resistance to structural deformation. Wear amount GUR 1020 was almost 30% higher.•Dispersion in friction due to variation in the intensity of wear mechanisms, abrasion (lower) and adhesion (higher).