Slow Release of Urea Encapsulated by Biodegradable Starch-PVA-Glycerol

Abstract

The influence of the blending ratio of biodegradable starch/polyvinyl alcohol (PVA)/glycerolin encapsulating urea for slow release has been investigated. It is found that water absorption capacity increased approximately 135% as the amounts of starch, PVA and glycerol in the composite film increase. Therefore, the swellability of the composite film is increased and the rate of the urea released from the composite film in wet environment higher. The FTIR explores the urea had been encapsulated successfully in the composite films. Moreover, the soil burial biodegradation results indicated that the biodegradability of the starch/PVA/glycerol/urea composite film strongly depended on the PVA proportion in the composite film matrix. The DSC results show that the higher concentration of PVA in composite film resulting less change of the melting enthalpy value because of crystalline regions of PVA remaining after biodegradation.