Optimizing Natural Rubber With Cassava Rhizome Biochar: A Multifaceted Evaluation of Rheological, Thermal, Mechanical, Physical, and Dielectric Properties

The goal of this research is to produce biochar, a bio‐reinforcing filler for natural rubber, from the agricultural waste cassava rhizome. The chemical composition, particle size, and morphology of biochar were examined. The effects of varying cassava rhizome biochar content on the rheological, thermal, mechanical, physical, and dielectric properties of natural rubber were investigated. The proportions of cassava rhizome biochar were 0, 5, 10, and 15 phr (parts per hundred rubber). The results showed that the chemical composition of the biochar was primarily carbon (80%), oxygen (19%), and potassium as a minor component (1%). The addition of cassava rhizome biochar reduced both the scorch time and cure time of natural rubber while increasing the crosslink density, which resulted in a decreased swelling index. Furthermore, the natural rubber compound experienced a decrease in its glass transition. The natural rubber/cassava rhizome biochar composites exhibited a slight increase in bulk density. The addition of cassava rhizome biochar enhanced all the mechanical properties of natural rubber. Specifically, adding 15 phr of cassava rhizome biochar increased tensile strength by 121%, 300% modulus by 114%, hardness by 61%, and tear strength by 21%. The dielectric constant of natural rubber increased by 7.8% with the addition of 5 phr of cassava rhizome biochar. Additionally, the morphology of the natural rubber/cassava rhizome biochar composites showed good distribution and adhesion between the biochar and the rubber matrix.