Optimum fabrication of Cereplast composites filled with vine fibers and calcium carbonate via cross mixture design.

The present study aims to optimize Cereplast composite materials' mechanical properties, using vine fibers as a reinforcing filler and calcium carbonate as a non-reinforcing filler. The composite samples were prepared in two steps. The first step involves extruding the different mixtures to obtain the granules. A twin-screw rotary cone extruder was used to make different composite formulations. The second step involves manufacturing the standardized specimens using a plastic injection press. Incorporating 20% and 40% vine fibers in the Cereplast matrix increased Young's modulus by 81.5 and 197.9%, respectively. However, the values obtained with calcium carbonate were much lower than those obtained with vine fibers. The tensile strength decreased with an increasing load content due to poor interfacial interaction between the fillers and matrix. The stiffness and brittleness of the composites increased with the loading rate, which reduced the composites' elasticity and led to lower elongation at break. A cross mixture design containing 13 trials has been set up and explored to study the effect of mixing proportions of polymers, vine fiber, and calcium carbonate on the synthesized composites. A three-component constrained mix design can limit the number of experiments to arrive quickly at the optimal mix design. The results of the mixing plane analysis showed that the second-degree model fits well and has good quality. The model correctly described the variation of Young's modulus with the proportions of the mixtures. Thus, increasing the contents of both fillers increases Young's modulus, but vine fibers' effect is more pronounced than calcium carbonate. [ABSTRACT FROM AUTHOR]