Effect of Mastication Time on the Curing and Dynamic Properties of Natural Rubber Gum Compounds: Towards Sustainable Rubber Processing

Research at a glance

Because of the high molecular weight of NR, effective mastication of natural rubber is a fundamental prerequisite which consumes a considerable amount of energy. However, excessive mastication, can lead to degradation of the material’s properties, potentially compromising final performance. Therefore, optimizing the mastication time is of great importance to ensure the energy efficiency and performance efficiency of the conversion process of natural rubber to rubber product. In this study, effect of mastication time on curing characteristics and dynamic properties of natural rubber compounds were investigated. The natural rubber compounds were masticated in an internal mixer with varying mastication time from 0 (control) to 7 minutes at six time intervals. Curing characteristics of the compounds and dynamic mechanical properties of the vulcanizates, were studied at 100 o C. It was found that curing characteristics were unaffected with the mastication time of 3 minutes, after which a delaying in both scorch time and cure time were observed. Similarly, dynamic properties of the rubber vulcanizates were also unaffected until the mastication is carried out within three minutes. It was evident from dynamic mechanical properties that possible natural rubber molecular changes are taking place as mastication time exceeds three minutes. Based on these observations, it is clear that sustainable rubber processing could be achieved through limitation of mastication for three minutes and prevention of excessive milling.