Simultaneous optimization of the mechanical properties of postconsumer natural fiber/plastic composites: Processing analysis

Abstract

In this work, manufacturing steps of composites were simultaneously analyzed to optimize four mechanical properties (flexural and tensile moduli, impact strength, and tensile stress at yield) of flax fiber/postconsumer recycled plastic composite. Eight parameters of the extrusion-injection process (extrusion: temperature profile and screw speed; injection: temperature profile in the barrel, mold temperature, injection speed, injection pressure, injection time, and back pressure) were selected. Process optimization, taking into account simultaneously all the mechanical properties (multi-responses optimization), required four steps: determination of influential factors by a screening design and an evaluation of the selected factors effects on the mechanical properties, modeling of the relationships between mechanical properties and significant factors by a Box–Behnken experimental design and a multiple linear regression analysis, identification of the potentially optimum conditions using the desirability function approach (Derringer–Suich model), and determination the optimum composite manufacturing conditions by a comparative analysis of the material relative qualities.