Composites based on green high-density polyethylene, polylactide and nanosized calcium carbonate: Effect of the processing parameter and blend composition

This paper describes the effect of composition and extruder screw rotation on the melt viscosity, degree of crystallinity, tensile properties and morphology of composites based on green high-density polyethylene (green HDPE), polylactide (PLA) and nanosized calcium carbonate (nCaCO3). A three-level central composite rotatable design was used to establish the composite formulation. The three factors studied were screw rotation (SR; 0-100 rpm), PLA content (0-35 wt %) and nCaCO3 content (0-5 wt %). The results showed that flow behavior of the composites depends on nCaCO3 content and SR. Polylactide and nCaCO3 levels influenced the development of green HDPE crystals, and the green HDPE matrix induced PLA dispersed phase crystallization. The solvent extraction method was efficient at revealing the morphologies of the composites, indicating a well distributed PLA dispersed phase in the green HDPE matrix. Additionally, nCaCO3 content contributed to reducing the particle domains of PLA by decreasing the interfacial tension between green HDPE and PLA. With respect to mechanical properties, the results showed that modulus of elasticity and tensile strength at yield are affected by PLA content. (C) 2016 Elsevier B.V. All rights reserved.