Selected Physical Properties of Extruded Foamed Materials Based on Starch

Abstract

Starch-based foamed materials were processed with extrusion-cooking. Potato starch was used as a basic raw material. Plastronfoam PDE and poly(vinyl) alcohol were added in the amount of 1, 2, and 3% of starch mass. Directly expanded foams were produced with the extrusion-cooking process at 80-110°C with 19% of initial moisture of blends. The processing was carried out at 100 and 130 rpm with two types of forming dies: round and ring of 3 and 5 mm of internal diameter, respectively. The obtained foams were put to cutting test to evaluate the durability of samples expressed in the maximum force needed to break the sample. The increasing amount of additives had a different influence on the foams’ hardness. Plastronfoam PDE lowered the cutting force of foams independently of the screw speed and forming die applied. An opposite trend was observed when poly(vinyl) alcohol was used as an additive. The samples shaped with the round forming die exhibited a higher hardness and better durability than the foams shaped with a ring die. The results could be helpful in management of optimum composition and treatment conditions to achieve desirable and sustainable products with desired properties.