B. Preparation of Biodegradable Starch-Polyvinyl Alcohol Blended Film with Slow-Release Phosphate Fertilizer

Abstract

The use of slow release fertilizer has become a new trend to save fertilizer consumption and to minimize environmental pollution.This paper discusses the preparation of starch (St)-polyvinyl alcohol (PVA) blended films by direct wet mixing process as the effectof different PVA loadings on phosphate fertilizer.  Degree of swelling and water retention properties were performed to measure theamount of water intakes of the fertilizer. For a given blend composition, the degree of swelling mostly increased with longer immersiontime.  However, at 5 g PVA content (St-PVA5), the maximum degree of swelling was still 618.43% at 60 min, and water retention of16.74% at 60 min.The phosphorus release behavior of prepared blended films in water was investigated. A soil degradation test wasperformed to measure the amount of weight loss. It was found that the degradation rate increased with PVA loading. Finally, the effectof the St-PVA blended film on the plant growth was also studied. The prepared St-PVA blended film has an effect on some agronomicalcharacteristics of the selected plant for cultivation.