On the enhanced thermal stability of self-healing polymers: Experiments and thermoelastic modeling

The remarkable elasticity, excellent resilience, and outstanding mechanical properties of NR has made it a candidate material for heavy-engineering applications ranging from, aerospace, automobile, defence, and allied rubber industries. However, the high degree of unsaturation in the polymer backbone of NR significantly reduces its resistance to oxidative degradation, thereby limiting its performance and durability in demanding environments. In the present study, we investigate sulfur-cured natural rubber (NR) and ionically modified epoxidized natural rubber (ENR) systems treated with dicarboxylic acid (DA) and dimethylimidazole (DMI). The novel high temperature bulge tests are performed to ensure their thermal stability under multiaxial state of stress. Constitutive modeling is also done to quantify theory in terms of the energy limiters. This study demonstrates that epoxidised NR treated with DMI/DA (ENR-DMI-DA) outperforms traditional sulphur-cured NR (NR-S) composites in terms of thermal stability up to a very high temperature of 423 K. The ultimate pressure at failure is observed to be 18% more for ENR-DMI-DA when compared with NR-S self-healing composites. The current study provides a brief insight for designers/researchers developing self-healing rubber composites for high-temperature applications. • Novel Bulge testing of self healing rubber composites. • Enhanced thermal stability of epoxidized natural rubber based composites. • Thermoelastic deformation and modeling of self healing rubber composites.