GOALI: Melt Processable Polymer Nanocomposites for Low Friction and Low Wear Applications

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Nearly every machine has at least one performance-critical sliding interface. Joints, bushings and bearings must operate reliably with low friction and low wear in order for the machine to move and perform desired tasks. The costs of friction and wear are estimated to be greater than $500 billion per year in the U.S. alone. There is a broad and substantial need to develop new materials for sustainable sliding applications. This award supports the development of an ultralow-wearing polymer system that can be manufactured by injection molding and other desirable manufacturing techniques. The relationship between DuPont and Lehigh University will enable the technical, industrial and commercial development of this material. Finally, despite the obvious impacts, education on tribology (friction and wear) is insufficient in the US, falling behind many countries. This project addresses these challenges through increased education, exposure and interest in tribology at all levels of society, including: 1) hands-on K-12 tribology experiments, 2) incorporating tribology in Lehigh engineering curriculum, 3) graduate and undergraduate student training at Lehigh and DuPont labs, and 4) provide industry engineers with seminars and online resources.This Grant Opportunity for Academic Liaison with Industry (GOALI) Program award supports a collaboration among researchers at Lehigh University and DuPont, to develop and study ultralow-wear melt processable fluoropolymer composites with goals of 1) understanding the relationship between tribological performance and material structure, composition, processing and operating conditions and 2) developing a complete mechanistic understanding of the complex tribomechanical and tribochemical processes in the sliding wear of ultralow wear perfluoropolymers. The intellectual merit is rooted in a mechanistic understanding of the substantial (10,000 x) improvement in wear performance of perfluoropolymers (e.g. perfluoroalkoxy -a melt processable fluoropolymer) with 5 vol percent nanofillers. The coupled, multi-scale, physical, material, mechanical and chemical mechanisms have been largely elusive. The hypothesized mechanism includes tribochemical chain scission of the fluoropolymer resulting in a transfer film that is covalently attached to the surface of a countersample as well as formation of virtual crosslinks (multiple end groups bonded to the nanofiller) that stabilize the wear surface of the polymer. The research will use student-built instruments to directly validate the hypothesized mechanism that in situ tribochemical reaction products alter the properties of otherwise inert fluoropolymers. A multi-faceted characterization approach will systematically test the hypotheses and discover new mechanisms of these materials that could, ultimately, enable science-based design of materials.