Evaluating the efficacy of a newly developed palm-based process aid on nitrile rubber composites

Abstract

The exploration of bio-based process aid is still ongoing in the effort to replace petroleum-based process oil. In this study, the efficacy of a newly developed palm-based process aid (Bio) on nitrile rubber (NBR) composites was investigated by varying its concentration from 0.0 to 10.0 phr. A comparison was made against a commercial oil (CO), i.e. naphthenic oil in terms of Mooney viscosity, cure characteristics, morphology, physical, and chemical properties. Results revealed that the use of Bio as process aid improves the processability of rubber by lowering the Mooney viscosity, enhancing filler dispersion, and lowering loss tangent values. Tensile properties and compression sets of CO-NBR composites were slightly better compared to Bio-NBR composites. Interestingly, Bio-NBR composites showed better ageing properties, especially at higher process aid content. Higher retentions of tensile strength and elongation at break and lower compression sets of aged Bio-NBR compared to CO-NBR composites were observed, which are possibly contributed by the good compatibility of Bio with aged rubber. Thermogravimetric analysis showed that the thermal stability of Bio-NBR composites were slightly better than CO-NBR composites. Based on these findings, the use of Bio (≥ 7.5 phr) as process aid significantly improved the processability of rubber with some enhancement in ageing properties of composites that is desirable and ideal for various applications such as for the production of automotive components.