Application of waste tire rubber particles in non-asbestos organic brake friction composite materials

Industrial, automotive, and municipal waste poses significant environmental and health issues if not treated properly. Over the years, some types of waste have been utilized successfully in recycling and in the development of new products. Therefore, in the current study, the applicability of waste tire rubber particles as functional additives to non-asbestos organic brake friction materials has been explored. The physical, mechanical, chemical and tribological properties of a series of rubber-containing friction materials have been examined. Results from standard European industry tests (ECE R-90) indicate that the tribological properties of the candidate friction materials are highly dependent on their waste tire rubber contents. The friction composite with lower tire waste rubber content exhibits a high and stable coefficient of friction, low fade, low frictional variability and the least fluctuations during sliding. On the other hand, the composite with the highest waste tire rubber content exhibits high recovery, lowest wear and the least disc temperature rise. Scanning electron microscopy of worn surfaces was used to reveal how the rubber content greatly influences the tribo-performance of the composites.