An in-house grade natural rubber from fresh field coagula and its vulcanisate properties

This study investigates an in-house grade natural rubber (NR) produced from raw fresh field coagula (FFC) using a new processing technology developed by the Malaysian Rubber Board (MRB). It was previously reported that FFC rubber has less dirt, ash and nitrogen content compared to SMR 10. In this study, gum and filled vulcanisates properties of the rubber were evaluated and compared with SMR 10 and SMR L. The results indicate that the Mooney scorch time (t 5 ) and time to optimum cure (t 95 ) of the FFC gum compound were comparable to SMR 10. The mechanical properties of FFC gum compound were similar to those of SMR 10, except for the compression set, which was closer to SMR L. This is due to relatively low non-rubber and dirt content. Comparative study of filled vulcanisate showed that the FFC rubber was comparable with SMR 10 in terms of basic physical properties such as tensile strength, hardness, modulus at 100% elongation and resilience at 60 phr filler content. In addition, a tyre tread formulation was also used to investigate the rheological, physical, and dynamic properties of FFC rubber reinforced with carbon black and silica at various filler content (0–90 phr). Carbon black- and silica-filled FFC rubber vulcanisates exhibited comparable tensile strength, tear strength and abrasion resistance. However, improvement in dynamic properties was observed in silica-filled FFC rubber where tan delta at 0℃ increased with higher silica content making it suitable as material for tyre tread with improved wet skid resistance. Overall, the findings of this work showed that the FFC rubber developed from the integrated model behaves similar to commercial technically specified rubbers (TSRs), although the raw material and process to produce the rubber are different from the conventional practices.