Optimisation of Formulation for Starch Modified Natural Rubber Composites by Using Response Surface Methodology

摘要

Starch modified natural rubber vulcanisates were prepared by the melt compounding method using a two-roll mill at a constant starch loading of 20 phr. Four formulation parameters consisted of black filler, white filler, silane coupling agent (SCA) and glycerol content in the composites which were optimised using two-level factorial design via response surface methodology (RSM). The cure characteristics and rebound resilience were selected as the responses. The significance of the factors and interaction were analysed using ANOVA and the model's ability to represent the system was confirmed using the constant of determination, R~2 for a value above 0.90. The R~2 values for all responses were obtained in the range between 0.96 and 0.99 which are close to the union (R~2 = 1). The final combination of factors used to achieve the highest rebound resilience and cure characteristics were with a high black filler loading of 60 phr and high glycerol of 5 % loading. These findings were further supported by morphological the characteristics observed under scanning electron microscopy (SEM). Therefore, the chemical modification using both glycerol and SCA was proven to improve the cure characteristics and rebound resilience value through the enhancement of the interfacial interaction between the starch and natural rubber (NR) particles. It is expected that the findings in this study will be useful for rubber product manufacturers to explore the possibility of producing biodegradable products in the future.