Investigating the effects of processing parameters on poly(lactic acid) properties – a central composite design approach

Abstract

This study attempts to optimise poly(lactic acid) processing parameters using central composite design approach which is well known statistical tool in design of experiments. Three factors and five levels were chosen for carrying out the analysis. The parameters include mixing temperature (180–210°C), screw speed (50–100 rev min⁻¹) and mixing time (5–10 min), which were varied independently. The results were evaluated based on maximum stress, tensile modulus, and impact strength under different conditions and the significant factors were determined using variance analysis (ANOVA). An optimum balance between the mechanical properties was obtained when the samples were blend at 180°C at 100 rev min⁻¹ rotor speed for 10 min. Moreover, validation of the predicted results confirmed the optimised parameters, which were further complemented by morphological and thermal studies.