Novel ingredients for sustainable brake pad friction materials: Benzoxazine resins and rice husk

This work explores two approaches aimed at improving the sustainability of automotive brake systems: incorporating rice husk as renewable raw material and using benzoxazine resins as an alternative binder in brake pad friction material formulations. The automotive brake system generates wear and PM emission during operation, contributing significantly to the traffic-related pollution. The need for the brake industry to address these emissions has been further promoted by the EURO 7 legislation, prompting a shift towards more sustainable brake systems. Rice husk and benzoxazine resins were chosen considering some attractive properties related to the friction material application but also to an actual industrial implementation, such as their favourable storing requirements. Four different friction material compositions underwent tribological testing on a reduced-scale dynamometer, also monitoring the airborne emissions. The contact surfaces were characterized through SEM, EDXS and XRD analysis. RH showed promising results towards a commercial application, and benzoxazine resin meaningfully lowered the wear of the friction material. • Braking performance was overall maintained with all modifications (RH, resin) • Benzoxazine-bound material showed superior wear behaviour • Rice husk suffered increased wear in harsh braking conditions • Friction layer extension correlated with wear and changed with modifications