Fine tuning microfibrillated cellulose dispersity and sulphur reactivities with dual modifiers for improving elastomer nanocomposite reinforcement

Micro fibrillated cellulose (MFC) is a promising filler that can reinforce elastomeric compounds, and make tire materials more sustainable, lightweight and highly reinforced. Due to the hydrophilic nature of MFC, modification is required to promote dispersion and adhesion in hydrophobic elastomers. The modification process can compromise fiber properties, and achieving both dispersion and adhesion simultaneously could be challenging. To address this, MFC was modified with both oleoyl chloride and acryloyl chloride and the dual modification process was controlled to reduce impact on the MFC fibers. The long chain oleoyl chloride was grafted to hydrophobized MFC to promote good dispersion while the acryloyl chloride was grafted with the goal of inserting reactive double bonds to promote adhesion by sulphur crosslinks between MFC fibers and curable elastomers. Interestingly, the modification process had negligible impact on both crystallinity and morphology while thermal stability of the modified MFC was improved. The modified MFC was used to partially substitute silica in styrene butadiene rubber (SBR)/silica (Zeosil MP200) cured nanocomposites. Our MFC design improved the properties of MFC/Silica/SBR nanocomposites, especially storage modulus, tensile strength by 30% and wear resistance by 60%, compared to those of non-acryloyl modified MFC and the standard silica-reinforced compounds.