Synergistic Effects of Metal Oxides in Styrene–Butadiene Rubber for High‐Voltage Cable Applications

ABSTRACT The demand for high‐performance materials in electrical insulation has increased in modern days. Keeping this in mind, we have developed polymer composite materials based on styrene butadiene rubber (SBR) and two metal oxides namely MgO and TiO 2 . To fulfill the requirements, we have prepared the composites using a two‐roll open mixing mill and tested their mechanical strength, flexibility, modulus, thermal stability, rheology, FTIR, morphology, electrical and dielectric properties, and most importantly the dielectric breakdown strength. The tested results indicate the highest crosslink density at ~6 phr, maximum tensile strength of 2.4 MPa and 3.2 MPa, T g shifts of +6.9°C and +5.4°C, and peak degradation temperature increases of +9°C and +7°C for SBR/MgO and SBR/TiO 2 composites, respectively, compared to pure SBR, at the optimum filler loadings. RPA showed increased G ′ and reduced Payne effect at 2–6 phr. FTIR verified that curing proceeds via sulfur/CBS‐activated pathways with intensified interfacial lattice bands Mg–O at 400–700 cm −1 and Ti–O/Ti–O–Ti at 400–700 cm −1 and Zn‐stearate formation 1390–1550 cm −1 . Differential scanning calorimetry analyses revealed the substantial shifting of glass transition temperature to higher value with the increase in both filler loadings up to 6 phr loading. The electrical conductivity, dielectric constant, and dielectric loss improved with filler loadings, particularly more improved for TiO 2 ‐filled composites. The dielectric breakdown strength exhibited 44% and 37% increment for SBR/MgO and SBR/TiO 2 composites compared to pure SBR, respectively, at the optimal filler loading 6 phr, beyond which it declines. The improvement in dielectric breakdown strength of our study has been compared with some similar types of published research work and it is revealed that this study provides valuable insights into the impact of filler type and loading on the properties of SBR composites, aiding in the development of advanced materials for high‐voltage cable insulation.