Effect of tannic acid chelating treatment on thermo-oxidative aging property of natural rubber

Metal ions are crucial in the production and preservation of fresh natural rubber latex. However, they also catalyze the thermo-oxidative aging of rubber products, leading to premature product degradation. This study investigates the use of tannic acid (TA) to chelate metal ions, thereby enhancing the thermo-oxidative aging resistance of natural rubber (NR). The findings indicate that NR treated with a 1.5 g·L−1 TA solution exhibits superior tensile strength, elongation at break, and crosslink density post-thermo-oxidative aging compared to untreated samples. Analysis of ultraviolet–visible absorption spectra, Fourier transform infrared spectra, and X-ray photoelectron spectroscopy confirms that TA’s resistance to thermo-oxidative aging stems from its ability to form stable chelates with metal ions, reducing their catalytic activity and mitigating oxidative degradation. Consequently, TA chelation treatment is proposed as an effective method to enhance the thermo-oxidative aging resistance of NR.