Response Surface Analysis of PS/EPDM/PA6 Ternary Blends: Effect of Mixing Sequence, Composition, and Viscosity Ratio on the Mechanical Properties

Abstract

In this work, effect of three factors on the phase morphology and mechanical properties of ternary blends based on polystyrene (PS)/ethylene‐propylene‐diene terpolymer (EPDM)/polyamide6 (PA6) was investigated by response surface methodology (RSM). Results indicated that among the studied factors (i.e., mixing sequence, composition, and viscosity ratio of the minor phases), the first two have the greatest effect on the impact strength (75.6%) and tensile properties (tensile modulus (84.9%) and yield stress (88.9%); while EPDM/PA6 viscosity ratio has the least effect (≤ 2.1%) on the final mechanical properties. These achievements are, in fact, arising from the considerable changes in the phase morphology and the contribution share predicted by experimental design outputs. However, mixing sequences just affected on the size of dispersed particles, but samples with different compositions presented different morphology types. According to the mechanical characterization of PS/EPDM/PA6 blends, the maximum impact strength and tensile properties were not obtained simultaneously. Optimal levels of input factors, aimed to balance impact strength and tensile properties, are M1 simultaneous mixing sequence, C1 composition (70/10/20), and V1 viscosity ratio (PA6 with low viscosity). J. VINYL ADDIT. TECHNOL., 26:282–290, 2020. © 2019 Society of Plastics Engineers