Aging Resistance and Antibacterial Properties of Natural Rubber Latex Composites Reinforced With Pre‐Dispersed Cerium Oxide Nanoparticles

ABSTRACT Natural rubber latex is widely used in biomedical applications for its elasticity and processability, yet it is vulnerable to thermo‐oxidative degradation and microbial attack during service. Conventional organic antioxidants and silver‐based antibacterial agents can alleviate these issues but are constrained by migration, potential toxicity, and high cost. Recently, nanomaterials have emerged as multifunctional additives to improve rubber durability and functionality. Cerium oxide nanoparticles (CeO 2 NPs), featuring reversible Ce 3+ /Ce 4+ redox behavior and enzyme‐mimicking antioxidant activity, can simultaneously enhance aging resistance and antibacterial performance, but uniform dispersion and effective interfacial interaction in natural rubber latex remain challenging. Here, a pre‐dispersion strategy enables homogeneous incorporation of CeO 2 NPs into silica‐reinforced natural rubber latex, delivering concurrent improvements in mechanical performance, aging resistance, and antibacterial functionality. At 6 phr CeO 2 , tensile strength, tear strength, and abrasion resistance increase by 16.06%, 15.91%, and 10.81%, respectively. After 48 h thermo‐oxidative aging, tensile strength and elongation retention reach 95.69% and 86.82%, indicating structural stability. The composites also show > 99.99% antibacterial efficiency against Escherichia coli . Overall, CeO 2 NPs act via synergistic reinforcement, free‐radical scavenging, and microbial inhibition, establishing them as environmentally friendly multifunctional additives for durable, hygienic rubber materials.