The Mechanism of Tribological Wear of Thermoplastic Materials

Molecular Deformation Mechanisms in UHMWPE During Tribological Loading in Artificial Joints

“…Wear as a result of creep leads to changes in the form and dimensions of the tibia inlays as well as molecular orientations without any loss of mass. This in turn influences the kinematics of the knee joint and therefore the tribological behavior [13]. It is known that close to the surface a highly oriented layer often occurs in UHMWPE during sliding [14][15][16][17].…”

Effect of Polypropylene Modification by Impregnation with Oil on Its Wear and Friction Coefficient at Variable Load and Various Friction Rates

“…However, when more heat is generated at higher linear velocity and thus temperature on the contact surface rises, the main wear mechanism becomes thermal wear. This type of wear is connected with deformation and next plastic flow of the material, which leads to its significant loss and, in consequence, to catastrophic wear [39]. As a result of thermal wear, value of friction coefficient decreases, so a change of shape of the friction torque curve can be confirmed by observation.…”

Friction coefficient and wear resistance of a modified polypropylene impregnated with different oils

“…13 , classic bearings can be used because a lubricant gap has already formed at this velocity value. In the research, for each variant of tribological pair and conditions of its work, constant values of sliding distance and load amounting to 1840 m and 343 N, respectively, were assumed.…”

“…However, at the high sliding velocity, when a higher temperature was generated, the predominant mechanism of wear was thermal wear, which was confirmed by observation of the worn surface. With this type of wear, spreading or even gluing of the rubbing surfaces often occurred, which led to catastrophic wear [13]. The thermal wear in the case of unmodified PP took place at sliding velocity between 0.44 and 0.62 m s −1 while in the case of impregnated PPs it took place at sliding velocity between 0.62 and 0.80 m s .…”

“…The evaluation of the functional features of the polymers is made on the basis of parameters describing their properties, such as the value of the coefficient of friction, the wear rate, the permissible operating temperature, and chemical resistance to materials with which they make contact. A major problem in the selection of the polymer is to determine the type of wear to which it will be subjected during operation, because depending on the type of material and loads, the wear process may occur in different ways [12,13].…”