保水型高分子缓释氮钾肥的制备及性能研究

Preparation and performance study of polymeric slow-release NK fertilizer with water absorbency

以氢氧化钾、丙烯酸(AA)、尿素为原料,N,N'-亚甲基双丙烯酰胺(NNMBA)为交联剂,过硫酸钾(KPS)为引发剂,采用溶液聚合法制备一种保水型高分子缓释氮钾肥(PSRNKF)。对PSRNKF进行傅里叶红外光谱测试,并推测其反应机理。研究了不同反应条件及不同盐溶液对PSRNKF吸水性能的影响。利用凯氏定氮法及火焰光度法对最佳工艺条件下制备的PSRNKF的全氮及速效钾含量进行了测试。结果表明,PSRNKF在去离子水中的吸水倍率最高可达919 g/g。不同阳离子盐溶液对吸水倍率的影响顺序为二价>三价>一价。PSRNKF的全氮质量分数为21%,速效钾质量分数为11%。在静水中培养120d,氮元素的累计释放率可达75%。

A new type of polymeric slow-release NK fertilizer （PSRNKF） with high water absorbency is prepared by solution polymerization method with caustic potassium, acrylic acid （AA） and urea as raw materials,N,N＇-methylene bisacrylamide （NNMBA） as cross-linker and potassium persulfate （KPS） as an initiator. The prepared PSRNKF is characterized by using Fourier transform infrared spectroscopy, and the reaction mechanism is also inferred. Effects of different reaction conditions and various salt solutions on water absorbency of PSRNKF are studied.Nitrogen content and available potassium content of PSRNKF prepared in the optimal process conditions is checked out by means of Kjeldahl method and the flame photometry method respectively.Results show that the water absorbency of PSRNKF is about 919 g/g in distilled water.The salt solutions with different cations have big effect on the water absorbency of PSRNKF,and the sequence of influence ability is divalence〉trivalence〉monovalence. The nitrogen content of PSRNKF is 21%, and the potassium content is ll%.The accumulated release rate of nitrogen is 75% when it has been cultivated in still water for 120 days.