膜特性对包膜控释肥养分控释性能的影响

Effects of coating properties of controlled-release fertilizers on nutrient release characteristics

为了研究膜特性对包膜控释肥养分控释性能的影响,该文通过膜的拉伸试验、扫描电镜和养分水中溶出率法对P1和P2树脂膜(不同包膜比率,不同添加剂含量)的机械性质、微观结构和养分控释特性进行了研究,结果表明,P1树脂膜机械性能较差,易发生龟裂现象,且通透性较大;P2树脂膜机械性能较好,但通透性较差;仅通过改变包膜比率不能达到改变两种膜的控释性能的目的。在不同包膜比率两种膜中分别添加适量的高分子疏水物质和可降解改性淀粉,可明显改善膜壳的机械性质、微观结构并起到了对养分释放速率的调控作用。两种膜材料包膜的控释肥料的控释性能均可通过改变各自的包膜比率和添加物的比例来调控,其关系可用函数关系模拟,且拟合度均达到显著水平。

In order to study the effects of properties of coating materials on nutrient release characteristics of controlled-release fertilizers, the experiments concerning tensile testing, electronic microscope scanning and nutrient release rate in water were conducted on mechanical properties and micro-structure of two coating materials, and nutrient release characteristics. The results showed that the coating mechanical properties of thermoplastic resin P2 were superior to that of thermoplastic resin P1, by contrast, the permeability of thermoplastic resin P1 was better than that of thermoplastic resin P2 ; besides, thermoplastic resin P1 tended to crack under the same conditions. However, the controlling capacity of two coating materials can＇t be achieved only by altering the coating rate. The results also showed that adequate amount of macromolecule water-repellent materials and adequate amount of degradable starches added to different coating materials could markedly improve mechanical property and microstructure, and thus control nutrients release rate. Accordingly, controlling capacity of nutrients in controlled-release fertilizers could be achieved by changing its coating rate and proportion of additives, the relation between them could be simulated by functions, and simulation equation achieved significant levels.