Wednesday, October 17, 2012

Starch foams



Starch-based composition foams were prepared by baking a mixture of starch and a synthetic biodegradable polymer in a hot mold. This process can be used to prepare a thin-walled object, such as a plate.

Scanning electron micrographs of the cross-sectional view of the foams showed that the cellular size is very dense in the outer layer and less dense in the inner layer. The effects of relative humidity, storage time, the presence of synthetic biodegradable polymers, and the presence of plasticizers on tesnile and flexural properties were investigated.

For all formulations, the amount of relative humidity which gave the maximum value of the ultimate strength of the foams wat 42%, while the storage time which gave the maximum value of the ultimate strength of foams was 2 days.

Addition of the synthetic biodegradable polymers improved the ultimate strength and the elongation at break of the foams. Increasing the plasticizer contents increased the elongation at break at the expense of the ultimate strength. Water absorption and biodegradability of the foams were also studied. Increasing the synthetic biodegradable polymer contents increased the water resisitivity of the foams. Enzymatic degradation tests showed that the foams were degraded by enzyme amylase

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