Cellulose and lignin as carbon black replacement in natural rubber

Lignocellulosic fillers have gained attention as biofillers due to their low cost, availability, and eco-friendly nature. Various lignocellulosic fillers from different sources having different chemical compositions have been used in natural rubber (NR) without sufficient comparison. So the objective of this study is to investigate the effect of two well defined industrial fillers (lignin and cellulose) along with black spruce cellulosic pulps obtained from an organosolv process on the properties of NR. To this end, a range (0/100–100/0) of lignin/cellulose (L/C) ratios is prepared. The biobased materials are chemically extracted from black spruce sawdust to partially replace carbon black (CB) in NR composites. The results show that higher L/C ratios provide higher tensile strength and elongation break, while lower ratios produce higher tensile modulus and hardness. These results indicate that a balance between different mechanical properties can be achieved by controlling the L/C ratio. A discussion on the total replacement of CB by lignin or cellulose is also presented to produce a more biobased compound.