Optimization of physical and mechanical properties of glycerol - modified natural rubber/starch - filled carbon black composites using two level factorial design

A statistical model was developed in this study to describe cure characteristic, rebound resilience and tensile strength of natural rubber/starch composites which was prepared by using a Haake internal mixer. Response surface methodology (RSM) based on central composite centered design (CCD) was employed to statistically evaluate and optimize the conditions for maximum cure characteristic, rebound resilience and tensile strength and study the significance and interaction of carbon black and glycerol on rebound resilience and tensile strength yield. The experimental runs were carried out according to a 22 full factorial design for the two identified design independent variables, namely, carbon black (X1) and glycerol (X2). With the use of the developed quadratic model equation, a maximum rebound resilience 71% was obtained to be a carbon black loading of 50 phr and glycerol loading of 7 %.