Optimizing Rubber Vulcanizate Performance: Investigating the Impact of Mixing Time on Rheological and Cured Characteristics Through Advanced Characterization

Abstract

The mixing process plays a crucial role in determining rubber compounds' rheological and mechanical properties, directly influencing their performance and durability. This study explores the impact of varying mixing times on the properties of rubber compounds based on natural rubber (NR) and styrene-butadiene rubber (SBR). By employing advanced characterization techniques such as the rubber process analyzer (RPA) and dynamic mechanical analyzer (DMA), key parameters including viscoelastic behavior, processability, hardness, tensile strength, resilience, aging resistance, crosslink density, air permeability, fatigue resistance, and so forth were systematically evaluated. The study also investigates filler–filler interactions and microstructural characteristics to establish a fundamental understanding of how mixing time affects material performance. Also, the Maier and Goritz model was utilized to predict rubber–filler interactions under different mixing conditions. The analysis of chain mobility using DMA provided insights into the molecular dynamics governing viscoelastic properties. Results indicate a 5-min mixing duration optimizes processability and mechanical performance in NR and SBR compounds. These findings highlighted the critical role of precise mixing time control in optimizing the quality, consistency, and longevity of rubber products, presenting valuable insights for enhancing general-purpose rubber formulations in industrial applications through advanced characterization techniques.