Toughening of natural rubber nanocomposites by the incorporation of nanoscale lignin combined with an industrially relevant leaching process

Strong and tough nanocomposite materials based on natural rubber (NR) latex demonstrate increasing potential to be used in advanced engineering applications and personal care products. Among many approaches for improving the toughness of NR-based products, the use of renewable and bio-based nanofillers is persuaded by environmental and economic trends. In this study, we report the preparation and incorporation of nanoscale organosolv lignin (OSL) particles in NR latex to improve its mechanical properties. We showed that the tensile strength, toughness, and Shore hardness of NR films reinforced with 5 wt % nanoscale OSL were improved by 39 %, 53 % and 12 %, respectively, while retaining high elongation at break (∼1800 %). This substantially improved mechanical property profile can be attributed to the enhanced nanoscale dispersion of OSL and the associated favourable interfacial adhesion of OSL with the NR matrix. Furthermore, the impact of an industrially applicable leaching process on the toughness and thermo-oxidative stability of rubber films is also discussed. For an instance, after the leaching process, the tensile strength, elongation, and toughness of 1 wt % OSL/NR were increased by 27 %, 9 %, and 32 %, respectively.