Effect of processing variables on mechanical properties of montmorillonite clay/unsaturated polyester nanocomposite using Taguchi based grey relational analysis

Abstract

Abstract The present investigation addresses the influence of process variables on the mechanical properties of montmorillonite (MMT) nanoclay with unsaturated polyester, using the mechanical shear mixing process. The rotational speed, mixing time, rotor blade design and clay content were chosen as process variables. The influence of these process variables on mechanical properties were studied with the help of grey relational analysis. Organically modified MMT nanoclay was used as the reinforcing filler, in order to increase the swelling of the clay with the polyester resin. Nanocomposites were fabricated based on the experimental design using the L9 orthogonal array. Among the parameters studied, blade design was identified as the parameter with the most influence, due to the presence of a varying shear force, which peeled off the clay platelets from the stacked arrangement of clay tactoids. Grey relational analysis was used to obtain the optimum process parameters for multiple quality characteristics such as tensile, flexural and impact strength. It was observed that the Shore D hardness values for all nine experiments possess higher values than virgin polyester. Morphological studies have been carried out for the specimen with optimum process parameters using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile, flexural and impact fractured specimens were studied using scanning electron microscopy (SEM) for optimum conditions.