Tea waste/carbon black hybrid filled natural rubber composites

This paper aimed to present the potential use of tea waste (TW) as an alternative filler for natural rubber (NR). Because of the bigger particle size of TW and is considered to be in a class of non-reinforcing filler. Carbon black (CB) was then introduced as secondary filler for NR matrix. This is to improve the performance of the composite while maintaining the suitable amount of TW. TW was fixed at 30 parts per hundred rubber (phr) where the CB was varied from 10 – 30 phr. Incorporation of CB in the hybrid system can fasten the curing process of the composites, as the scorch and curing times increased with increasing the CB contents. CB has greatly influenced the maximum torque, tensile strength and tensile modulus due to its better rubber-filler interaction within the rubber matrix. However, the elongation at break of the composites drop continuously with the addition of the CB. This is simply due to dilution effect of the composite which refers to the less amount of flexible phase. The enhanced performance of the composite in the presence of CB can be verified by the calculation of rubber-filler interaction (Q f /Q g ) values, indicating higher rubber-filler interaction when higher amount of CB was used. Apart from that, the images obtained from scanning electron microscope (SEM) also provided some evidence relating to the tensile properties observed. From the experimental results, hybridization of 30/20 phr/phr of TW and CB is highly suggested to gain the synergistic strength and processing safety.