Improving Mechanical Properties and Aging Resistance of Natural Rubber Composites by Modification of Zirconium Dioxide Nanoparticles Synergized With Chitosan and Zinc Dimethacrylate

Aiming at the poor reinforcement and aging resistance of natural rubber (NR), this study proposes a strategy to fill NR with zirconium dioxide (ZrO 2 ) nanoparticles synergistically modified by chitosan (CS) and zinc dimethacrylate (ZDMA). First, CS is grafted on the surface of ZrO 2 to construct a cladding layer rich in amino(NH 2 ) and hydroxyl(OH) groups. Then, the carbon–carbon double bond(CC) of ZDMA undergoes an addition reaction with the NH 2 of CS. CS synergizes with ZDMA to trap free radicals in the matrix and act as an antioxidant, while simultaneously improving the cross‐linking degree of the composites. Research data show, NR composites exhibit optimal performance when the CS concentration is 0.6%, achieving tear and tensile strength, abrasion of 64.51 kN/m, 28.93 MPa, and 143.79 mm 3 respectively. These values represent 19.92%, 26.46%, and 15.9% improvements over the unmodified system. The tensile strength retention rates remain at 87.16% and 93.88% after 48 h of thermo‐oxidative and humid‐heat aging, respectively, demonstrating excellent aging resistance. This study provides innovative solutions for developing high‐performance aging‐resistant rubber materials.