Date of Award
Doctor of Philosophy
Christian J. Schwartz
This work examines two high performance polymer tribology systems. Polyetheretherketone (PEEK) is a high temperature, low wear thermoplastic that has potential for several modern industries, but the understanding of its wear mechanisms in relation to transfer film is not well understood. An investigation into these mechanisms would benefit the utility of PEEK in several applications. The second polymer system investigated is high performance silicone used in implantable cardiac devices (ICDs). Understanding the wear mechanisms of silicone in-vivo is challenging, and examining the fundamental causes of wear would benefit device design in surgical implantation methods. First, the viability of using finite element analysis as a way to understand fundamental contact behavior is investigated. It was found that for high-level contact models, average roughness is a weak sole descriptor of contact behavior. Next, two PEEK studies in dry sliding were conducted. The first study examined multi-linear and reciprocating sliding in relation to roughness orientation, while proposing hypotheses to explain transfer film behavior. The second PEEK study, examined the development of transfer film and wear with respect to roughness orientation for a variety of sliding distances. From these studies, it was found that frictional heating affects the volume of transfer film, multi-directional sliding and reciprocation play a role in wear and transfer film development, and roughness orientation can greatly impact both wear and transfer film of PEEK. Lastly, a silicone lead in implantable cardiac devices was studied by using three key parameters thought to affect its wear: load, albumin protein, and silica abrasive. It was found that none of these parameters greatly impacted the wear scar metrics, but silica and albumin can lead to wear mechanisms that might impact long-term wear or other wear modes.
Placette, Mark, "Friction and wear mechanisms of high performance polyetheretherketone and silicone" (2018). Graduate Theses and Dissertations. 17289.