An in-depth investigation into filler-filler interactions in rubber compounds through dynamic analysis methods

Abstract

This study investigates the complex dynamics of filler-filler interactions within rubber compounds, utilising advanced characterisation techniques. Effective dispersion of fillers within the rubber matrix is crucial for achieving optimal performance in vulcanised products. The absence of effective filler-rubber interaction can significantly impact the performance, reliability and lifespan of rubber products across diverse industries and applications. Hence, it is necessary to attain optimal filler dispersion and interaction within the rubber matrix to secure the desired properties and quality of the product. In this study, various industrial tools such as the Dynamic Mechanical Analyser (DMA) and Rubber Process Analyser (RPA) were employed to thoroughly examine the filler-filler interplay. Notably, a strong correlation coefficient exceeding 0.9 was observed, indicating a high degree of consistency between these two techniques. While RPA offers valuable insights into the processing behaviour of rubber compounds, DMA provides more detailed information on the structural and mechanical changes occurring in the rubber-filler matrix during and after vulcanisation. The investigation focuses on two rubber matrices: Natural Rubber (NR) and Styrene Butadiene Rubber (SBR). Three series of carbon black with varying particle sizes (N134, N339, N774), as well as silica, either individually or in combination, were utilised as fillers. Additionally, the effects of annealing before and after vulcanisation, along with the resulting mechanical properties, were analysed in depth. The deeper insights afforded by DMA can contribute to a more comprehensive understanding of the underlying mechanisms responsible for performance limitations and product failures, such as insufficient filler dispersion or flocculation during vulcanisation.