A screw configuration was successfully developed, so as to carry out the plasticization of starch as well as the
foaming of starch, in the same extruder. A biodegradable starch foam was successfully obtained where water functions as
the plasticizer as well as the blowing agent, talc as the nucleating agent, and PHAE imparts flexibility and processability.
The optimum input levels of water and PHAE were determined. The expansion ratio increased with an increase in the
amount of water injected into the system, but up to a certain extent only. The degree of foaming reduced when the water
used was more than 7% of the starch used in the system. Minimum density of starch foams was obtained at a PHAE
concentration of 7%, with sufficient flexibility. A large expansion ratio was obtained by optimizing the processing
temperature, and the die temperature, which helps prevent the loss of blowing agent through the surface of the foam. The
existent technology to make starch based loose-fill was successfully translated to manufacture foam sheets. The extruded
starch foam sheets provide excellent insulation properties. The R-values obtained suggested better insulation characteristics,
as compared to expanded polystyrene, and efforts are in progress to enhance their thermal resistivity to make them
comparable to polyurethane foams. Also, the dynamic cushioning data reveals that the starch foam sheets provide decent
cushioning or shock absorption properties. Future work is headed towards improving hydrophobic characteristics as well as
the cushioning properties of these starch foams, in order to increase their viability in the market.