Improved cure characteristics and mechanical properties of an epoxidized natural rubber filled with cerium oxide nanoparticles: Influence of epoxide levels and filler loading

Abstract

In this study, cerium oxide nanoparticles (nanoceria, CeNP) were used as a nanofiller in epoxidized natural rubber with varying epoxide levels, including 25% epoxidation (ENR‐25) and 50% epoxidation (ENR‐50). Co‐precipitation methods were employed to synthesize a pure phase of CeNP with an average particle size of 11.4 ± 2.0 nm. CeNP was characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), and X‐ray photoelectron spectroscopy. The effect of CeNP loading with 0–3 parts per hundreds of rubber (phr) on the properties of rubber nanocomposites was explored. ENR‐25 nanocomposites with 1 phr of CeNP exhibited higher tensile strength and elongation at break compared to ENR‐50 nanocomposites. These findings correspond to a lower Payne effect, improved scorch safety, and better processability. The strongest and most effective CeO2–ENR interactions via silane linkages are expected to outperform sulfur crosslinking in ENR‐25 having 1 phr of CeNP. Microstructural evaluation of an ENR‐25 sample containing 1 phr of CeNP indicated well‐distributed nanofillers in the ENR‐25 matrix, indicating that CeNP and ENR‐25 appeared to be well‐matched. Hardness of all ENR nanocomposites increased with CeNP loading. The cracking resistance, creep properties, and thermal stability of rubber nanocomposites were unaffected by addition of CeNP in the ENR‐25 and ENR‐50 samples.