A Bio‐Composite Based on Fluoroelastomers and Cellulose: A Sustainable Reinforcement Strategy

Carbon black (CB) is widely used as a reinforcing filler in fluoroelastomers (FKM) to improve mechanical properties, but it often contains harmful organic impurities such as polycyclic aromatic hydrocarbons (PAHs), raising environmental and health concerns. This study presents a bio‐composite based on FKM and cellulose, a natural biopolymer composed of glucose units linked by β‐glycosidic bonds, as a sustainable alternative. Cure, mechanical, and thermal properties of the FKM/cellulose composites were evaluated and compared with FKM‐carbon black composites. Rubber process analyzer (RPA) results showed a significant increase in the state of cure from 10.7 to 27.2 dN m with cellulose addition. Tensile strength improved markedly from 1.3 to 6.7 MPa at 20 phr cellulose loading, as measured using a universal testing machine (UTM). The state of cure for the FKM composite containing 20 phr cellulose and the FKM/CB composite was found to be 27.2 and 28.1 dN m, respectively dynamic mechanical analysis (DMA) revealed enhanced storage modulus and an increase in glass transition temperature ( T g ) with cellulose incorporation. Overall, cellulose demonstrates strong potential as an eco‐friendly reinforcing filler for FKM, offering comparable performance to CB while addressing environmental concerns. This bio‐composite demonstrates promising application prospects in different automotive components such as seals, gaskets, and hoses, where the combination of fluoroelastomer performance and sustainable reinforcement can meet the growing demand for durable yet environmentally conscious materials.