Screening of stabilized crosslinked polyethylene using a novel wear tester

Article type: Research Article

Authors: Hoffmann, M.^; | Gonzalez‐Mora, V. | Chiesa, R. | Cigada, A. | Stroosnijder, M.F.

Affiliations: Institute for Health and Consumer Protection, The European Commission, 21020 Ispra (Va), Italy | Politecnico di Milano, Dipartimento di Chimica Fisica Applicata, via Mancinelli 7, 20133 Milano, Italy

Note: [] Corresponding author: Tel.: +39 0332 786282; Fax: +39 0332 789385; E‐mail: [email protected].

Abstract: A novel pin‐on‐disk type wear tester is described allowing a rapid screening of different types of polyethylene under both unidirectional and multidirectional sliding motion. The wear of four polyethylene materials sliding against a roughened CoCrMo alloy was evaluated: a non‐irradiated UHMWPE, a UHMWPE irradiated with a dose of 25 kGy in air, and two types of crosslinked UHMWPE (100 kGy, air), which were subjected to a stabilization heat treatment in nitrogen at 155°C for 72 hours (XLPE I) and in water at 130°C for 72 hours (XLPE II), respectively. Under multidirectional sliding conditions both types of XLPE exhibited significantly less wear with respect to the 25 kGy irradiated UHMWPE and the non‐irradiated UHMWPE, even under the rough counterface conditions applied. Under unidirectional sliding motion both types of XLPE exhibited the highest wear of all materials tested, because the orientation hardening effect acting under linear lubricated condition is less pronounced for crosslinked polyethylene.

Journal: Bio-Medical Materials and Engineering, vol. 12, no. 4, pp. 387-395, 2002