Abstract
This study examines the use of acrylic acid–modified halloysite nanotubes to achieve simultaneous reinforcement and intrinsic self-healing in natural rubber via reversible ionic interactions. Surface modification of halloysite nanotubes (2–8 wt.% acrylic acid) improves compatibility with the non-polar rubber matrix and introduces carboxylic groups that enable reversible Zn²⁺ mediated interactions with zinc thiolate functionalized rubber, forming dynamic networks. An optimal composition at 6 wt.% grafting shows a balanced enhancement in performance, delivering ~35% higher tensile strength along with near-complete healing efficiency. These findings highlight a synergistic mechanism where acid-modified nanotubes function as both reinforcing agents and active healing enablers, offering a practical strategy for designing robust, self-healing rubber composites.