Abstract
For the development of the biodegradable packaging material, expanded starch of loose-fill type was produced on a twin screw extruder. The processing variables were the mixture ratio between starch and additives (PVA, CaCO$_3$), temperature and screw speed. The physical and compressional properties of the expanded starch were examined against processing variables. The content of CaCO$_3$ was a very important factor affecting the physical, structural and compressional properties of the expanded starch. The interior structure of the expanded starch showed closed cell structure with increase in the content of CaCO$_3$. But the compressional energy and rate linearly decreased with the increase in the content. The compressional resilience was increased with the increase in the temperature at the front extruding zone, but it decreased at high temperature.
