Abstract
Physico-chemical and mechanical properties of extruded cornstarch-poly(lactic acid) (PLA) with addition of ceric ammonium nitrate (CAN) were investigated. An addition of 0.25% CAN improved bulk density and hardness of the extrudates, but 0.5 or 1.0% CAN addition reduced expansion, and increased bulk density and hardness significantly. Water solubility was increased, but cohesiveness was decreased with increasing CAN concentration. An addition of 0.25% CAN decreased thickness of the extrudate cell walls to about 20 μm in comparison with that without CAN (50-10 μm). This corresponded to a decrease in bulk density of the extrudate. Size exclusion chromatography showed that the addition of CAN accelerated the degradation of starch during extrusion. Furthermore, with 0.5 or 1.0% CAN the extrudates expanded poorly and there was no peak at the void volume. PLA molecules have not been degraded by CAN addition.
