Fluoro-modified epoxidized natural rubber for superior performance in industrial applications
Kanokwan Phraeksong, Siwarote Boonrasri, Sunisa Suchat
Abstract
This study demonstrates a pioneering approach to synthesize fluoro-modified natural rubber (FNR) via hydrofluoric acid (HF) treatment of epoxidized natural rubber (ENR). Structural confirmation of fluorination was definitively established through comprehensive FTIR and NMR spectroscopies, including 1 H NMR, 13 C NMR, and 19 F NMR, which were employed to confirm the structure of the FNR. The key characteristic fluorine signal at −148.78 ppm in 19 F NMR spectrum and the distinctive C-F stretching vibrations at 1020 cm −1 in FTIR spectrum provide evidence of the fluorine incorporation into the rubber backbone. The performance characteristics of FNR revealed it exhibiting the highest maximum torque (0.96 dNm) and having improved mechanical properties: the highest tensile strength (14.1 MPa), 100 % modulus (1.0 MPa), and hardness (36.1 Shore A) when compared to both ENR and unmodified natural rubber (NR). FNR demonstrated excellent resistance to oil with only 0.72 % swelling in diesel, and thermal stability at up to 406°C when tested by thermogravimetric analysis. Therefore, FNR can reduce costs while maintaining oil and heat resistance properties comparable to high-grade materials like FKM, making it well-suited for use in fuel system components that require a balance between performance and cost. The development of FNR represents a significant contribution to sustainable materials science as an advanced performance material from renewable natural rubber resources.