Practicality of bioderived coconut oil as a plasticizer for ethylene propylene diene monomer

As a petroleum-based process oil, paraffin oil is widely used as a plasticizer for ethylene propylene diene monomer (EPDM). However, petroleum is non-renewable and facing depletion. Coconut oil is an environmentally friendly, relatively low-cost, renewable, and natural bio-based oil. Therefore, in this study, the feasibility of replacing paraffin oil with coconut oil as a plasticizer for rubber production was investigated. Different proportions of coconut oil and paraffin oil were used as plasticizers in EPDM blends. The curing characteristics, physical properties, rheological properties, thermal stability, and dynamic mechanical responses of the EPDM blends were evaluated. Experimental results revealed that coconut oil has a better plasticizing effect and can improve the processing safety of rubber blends; the mechanical properties and thermal stability were slightly reduced but were in the processable range of rubber. Furthermore, when coconut oil was added at no more than 15 phr (parts per hundred rubber), there was no risk of blooming in the EPDM blends. Therefore, coconut oil has great potential to replace petroleum-based process oils used in various rubber fields as green bio-based process oils. • Introduction of bio-based coconut oil combined with paraffin oil as plasticizer. • The effects of plasticizer blend ratios on rubber properties were evaluated. • Adding coconut oil improves the processability and plasticity of rubber composites. • Coconut oil has the potential to be used in rubber composites at appropriate dosages.