Assessment of oil palm ash and compounding ingredients on tensile properties of acrylonitrile–butadiene rubber using statistical design

Abstract

Various types of chemical ingredients are needed in the rubber compounding process to obtain desired properties for a commercially useful application. To content with this, Plackett–Burman design (PBD) provides an efficient way of dealing with a large number of variables and identifying the most important parameter. This study reviews the exploitation of PBD to screen the significant effect of different compounding ingredients as well as oil palm ash (OPA) to the tensile properties of acrylonitrile butadiene rubber (NBR). The two most significant components were chosen for each tensile property. Furthermore, three-dimensional plots and their respective contour plots were used to investigate the simultaneous interactions of different factors on the responses studied. Based on the result obtained, the tensile strength showed an increasing trend when N-cyclohexyl-2-benzothiazole sulfenamide (CBS) concentration increased; however, the increase in stearic acid has resulted in a decline in tensile strength. On the other hand, the sulphur crosslinker with the largest effect value has shown a significant reduction towards the elongation at break. For tensile modulus, sulphur and OPA which are the two most significant variables had contributed to a synergistic effect as the concentration increased.