Study on the Preparation of Starch-Based Polyampholyte and Slow Release Performance

The starch-based polyampholyte (SPAM) was synthesized by graft copolymerization of starch with acrylamide (AM) and acrylic acid (AA). The structural and chemical characteristics of the product, as well as its efficiency in slowing the nitrogen release and water evaporation in soil were examined. The slow-release effect of SPAM was better than starch, starch-g-SPAC (Sodium polyacrylate) and starch-g-PVAC (Polyvinyl ammonium chloride) for urea release, particularly when the pH of SPAM solution was equal to 5(approached or equaled to isoelectric point, IEP). These studies showed that the product with good slow-release and being environmentally friendly is biodegradable carrier materials.