Eggshell improves dynamic properties of durable guayule rubber composites co-reinforced with silanized silica

Abstract

Bio-renewable, inexpensive, reinforcing fillers for rubber composites are being developed to replace nonrenewable versions, in order to reduce carbon footprint of production. In this study, bifunctionally silanized silica (BSS), a commercial synthetic filler, was partially or completely replaced by micro-sized eggshell (ES), at three different loadings, in guayule (Parthenium argentatum, Gray) natural rubber (GNR) composites, and the dynamic mechanical properties, and durability (resistance to aging, fatigue and ozone) were characterized.Replacement of BSS with ES decreased the dynamic property of estimated rolling resistance, more than BSS by itself and, unusually, concomitantly increased the estimated wet grip of GNR composites. The composites filled with ES and BSS had comparable resistance to aging and fatigue. However, ozone resistance was greatest in composites made with a mixture of the two fillers. Durable GNR composites made with ES and BSS with improved dynamic mechanical properties, may support further expansion of the GNR industry.