Sustainable reinforcement of natural rubber with redispersed cellulose nanofibers assisted by lignosulfonate: Enhancing mechanical, anti-swelling, and self-healing properties

Nanocellulose has gained significant attention as a sustainable reinforcing agent for enhancing the mechanical and functional properties of natural rubber (NR) composites. However, the practical application of nanocellulose is often limited by challenges in redispersion after drying, which can lead to poor filler dispersion and weak interfacial compatibility with the hydrophobic NR matrix. This study presents a novel approach for overcoming these challenges by using sodium lignosulfonate (LS) to aid in the redispersion of TEMPO-oxidized cellulose nanofibers (TOCN), resulting in redispersed TOCN/LS (Re-TOCN/LS) systems. The Re-TOCN/LS was incorporated into NR to prepare high-performance NR-RTL composites. At a low filler content (1 wt%), the NR-1 %RTL composites exhibited a significant improvement in mechanical properties, with tensile strength increasing from 0.8 ± 0.2 MPa to 1.1 ± 0.1 MPa, and toughness enhancing from 7.1 ± 1.2 MJ/m³ to 10.7 ± 1.8 MJ/m³ . Scanning electron microscopy (SEM) analysis confirmed the homogeneous dispersion of TOCN in the NR matrix, which was attributed to the synergistic effects of LS. Additionally, the NR-1 %RTL composites demonstrated enhanced resistance to solvent swelling, reducing the toluene absorption rate by 1200 %, and exhibited impressive self-healing properties, retaining a tensile strength of 1.0 ± 0.3 MPa after healing. These findings highlight the potential of Re-TOCN/LS systems as an effective, environmentally sustainable reinforcement strategy for improving the mechanical, anti-swelling, and self-healing properties of NR composites, with important implications for advancing green materials in industrial applications. • Sodium lignosulfonate (LS) enables the redispersion of TOCN for natural rubber composites. • With only 1 wt% filler content, the Re-TOCN/LS system improves natural rubber's tensile strength from 0.8 MPa to 1.1 MPa and toughness from 7.1 MJ/m 3 to 10.7 MJ/m 3 . • The composites demonstrate excellent solvent resistance and maintain 1.1 MPa tensile strength after self-healing.