Response Surface Methodology Approach for Optimization of Extrusion Process of Production of Poly (Hydroxyl Butyrate-Co-Hydroxyvalerate) /Tapioca Starch Blends

Abstract

Abstract Response surface methodology (RSM) was adopted to investigate the optimum operation conditions to develop the biodegradable pellet and to analyze the effects of extrusion processing variables, including tapioca starch content (30–50 %), xylitol content (45–75 g) and barrel temperature (140–170 °C) on characteristics of the Poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV)-starch composites. Maximum loading and maximum displacement of composites could be improved with a deliberate amount of xylitol as well as with rising barrel temperature. The water absorption reduced by addition of xylitol in comparison to increasing tapioca starch content. Coefficients of determination were higher than 0.85 of the response variables and significant regression models were applied to RSM optimization. Based on the response surface and superimposed plots, the compromised optimization condition obtained by numerical optimization was 39.04 % of tapioca-starch content, 56.99 g of xylitol content and 156.58 °C of barrel temperature.