Parametric Study of Twin Screw Extrusion for Processing Epoxy/Carbon Black Nanocomposites Using Orthogonal Array Technique

Abstract

Abstract

This paper presents the experimental investigation of the influence of process parameters of twin screw extrusion on the dispersion and electrical, thermal and mechanical properties of epoxy/CB nanocomposites. Four factors, namely, loading level of carbon black (0, 2, 4, 6, 8 and 10 wt%) in epoxy, screw speed (75, 100 and 125 rpm), temperature (5 °, 15 ° and 30 °C) and number of passes (5, 10 and 15) were selected for the design of L₁₈ OA layout. Response factors such as electrical resistivity, glass transition temperature, microhardness and impact strength of epoxy/CB nanocomposites were studied. Highest electrical conductivity was observed at 10 wt% CB loading, 30 °C, 5 passes and 100 rpm. Highest microhardness, impact strength and glass transition temperature were obtained at 10 wt%, 15 passes, 75 rpm and 15 °C. From TGA, the addition of CB to epoxy resulted in improved thermal stability. ANOVA of the experimental results showed that CB loading had significant influence on all the responses, followed by number of passes. The Grey relational grade was highest for factor level combination 10 wt% CB loading, 15 passes, 15 °C and 75 rpm. Volume conductivity increased from 4.92 × 10⁻¹⁵(epoxy) to 2.2 × 10⁻⁵ S-cm⁻¹ (10 wt% CB/epoxy). Similarly, microhardness, glass transition temperature and impact strength increased by 29.96, 35.92 and 69.23% respectively due to the addition of 10 wt% CB to epoxy, corresponding to the best parameter combinations obtained by Grey relational analysis.

Keywords: carbonblack (CB), orthogonal array (OA), thermo-gravimetric analysis (TGA), DOE: design of experiment, analysis of variance (ANOVA)