Wood Flour as a Filler of Natural and Epoxidised Natural Rubber

Abstract

It was found that the wood flour (WF; both from coniferous trees and deciduous trees) can be used as the fillers of natural rubber (NR) or epoxidised natural rubber (ENR). It was confirmed by the decrease of the curing time, especially in the case of ENR. The incorporation of WF into rubbers positive effects on the crosslinking density, wherein the wood flour derived from coniferous trees influences more those properties, that are associated with a greater surface area of this filler. Both types of WF weaken the tensile strength and elongation at break, but clearly improved stress at 100, 200 and 300% elongation. The presence of epoxy groups in the ENR does not lead to a greater reinforcement of this elastomer with wood flour in relation to natural rubber without functional groups on the surface. Additionally it was found that the WF content in NR or ENR vulcanisates leads to the formation of more amount of disulfide crosslinks and simultaneously causes lower friction coefficient of obtained vulcanisates.