Analysis of Dynamic Mechanical Responses of Carbon Black Filled Natural Rubber Composites Using Shear and Tensile Testing

ABSTRACT Natural rubber / high abrasion furnace (HAF) carbon black were prepared, and the frequency‐ dependent dynamic mechanical properties were investigated. Dynamic mechanical characterization was carried out using both Rubber Process Analyzer (RPA) and Dynamic Mechanical Analyzer (DMA) operating under different deformation modes. Despite the differences in testing geometry, comparable viscoelastic trends were observed between the two techniques, and a correlation between the dynamic mechanical parameters obtained from DMA and RPA could be established over the investigated frequency and filler‐loading ranges. The incorporation of carbon black significantly enhanced the modulus of the composites owing to the development of filler–rubber interactions and filler network formation within the NR matrix. The experimentally obtained modulus values were compared with theoretical reinforcement models, and the Modified Guth–Gold and Modified Fukahori Guth–Gold equations showed reasonable agreement with the experimental results. Time–temperature superposition analysis was employed to construct master curves for predicting the long‐term viscoelastic behavior of the composites beyond the experimental frequency range. The influence of the bifunctional organosilane coupling agent, bis (3‐triethoxysilylpropyl) tetrasulphide (TESPT), on the cure characteristics, mechanical performance, and filler‐rubber interaction of NR/HAF composites was also investigated. The presence of TESPT improved the cure rate and enhanced the tensile properties, particularly at lower filler loadings, indicating improved interfacial interaction between the rubber matrix and carbon black filler.