Studies On The Membrane Property And Evaluations Of Starch Acetate

The utilization ratio of nitrogenous fertilizer is intimately related with economy and sustaining development of agriculture in China. At present, the technology of controlled release has been used home and abroad as an effective method to increase the ratio. However, the application of controlled release fertilizer is limited by its high cost and environmental pollution brought from membrane materials of synthesized polymer with low degradation. The National High Technology Research and Development Program of China (863 Program), "A New Type of Controlled release fertilizer: Research, Preparation and Industrilization", is charged by our research group to develop a new membrane material. In this paper, a preliminary study was performed to investigate starch acetate produced by our laboratory as the new material. Evaluation methods were established to investigate the relationship between property and structure of starch acetate and to provide theoretic and experimental evidences for further research.1 , The parameters of starch acetate such as the degree of substitution (DS), solubility and thermostability etc. were evaluated. A new method of acid-alkali titration was established to determine the DS of starch acetates rapidly and accurately. It was also found that thermostability and liposolubility of starch acetate with high DS were improved compared with starch.2 The factors including DS, substrate materials, humidity and the solvent concentration temperature of casting solution were investigated with the casting method. Compact membranes were prepared. Results showed that the capability of membrane was correlated with the DS of starch acetate and more compact membrane was obtained with higher DS starch acetate.3 Weight loss was measured to investigate the water-resistance and soil degradation of starch acetate. Results showed that weight loss was 13% in water after 24 hours and 18% in soil after 24 days. This suggested that better water and biological stability can be achieved through higher DS.4 Urea coated with SA was selected as a model to investigate the membrane property of controlled release and the colorimetry of 2,3-butandione dioxime was established to evaluate it. Results showed that starch acetate can be employed as membrane material for controlled release.