Enhancing insulation and flexibility of starch/Poly(butylene adipate terephthalate) (PBAT) blend foam by improving rheological properties in extrusion process

Abstract

Enhancing insulation and flexibility of starch/Poly(butylene adipate terephthalate) (PBAT) blend foam by improving rheological properties in extrusion process This study investigated the effect of blending with starch/PBAT on foaming behavior and physical properties during foaming processing. The starch/PBAT blend ratio was controlled by various blending ratios (0, 10, 15, 20, 25 wt %) to determine the effect on the interaction and characteristics of blended foam. The blending of starch and PBAT resulted in remarkable improvement in expansion ratio and rheological properties, according to decreased complex viscosity by PBAT during processing. P20 and P25 samples show the highest expansion ratio and low density by decreased complex viscosity, and the P20, P25 samples with too much flowability showed reduced phenomenon due to rapid cell wall contraction. This phenomenon could also be confirmed by scanning electron microscopy (SEM) images. The thermo-insulation performance improved with high expansion ratio and reduced density. The flexural strength and resilience through blending with PBAT were increased up to 349.5 % and 108.5 %, respectively. In addition, structure of a molten PBAT coating around the foamed TPS cell wall improved the disadvantages of the starch foam, which is sensitive to moisture, and increased moisture resistance. The eco-friendly thermo-insulator made through the blend foam of starch/PBAT shows similar insulation performance to commercialized insulation or reported studies, and can be expected to be applied as an eco-friendly packaging material for starch/PBAT foam.