一种新型保水缓释氮肥有关特征及性能

Characteristics and Performance of A New Water-Absorbent Slow Release Nitrogen Fertilizer

【目的】采用物理、化学方法研究一种以化学聚合反应共聚合成的新型保水缓释氮肥的特征和性能。【方法】采用红外光谱分析、电镜观察、差示扫描量热分析和热重分析等方法观察、解析及测定肥料有关特征和性能。【结果】保水缓释氮肥吸水倍率可达103 g·gP-1,含氮量达30%,酸碱度接近中性,是盐度指数极低的肥料。保水缓释氮肥的原料氮肥与保水材料之间通过氢键作用形成了共聚体,具有亲水基团,这是形成吸水保水的化学机制。保水缓释氮肥是一种吸水膨胀而不溶解的凝胶,是整体不均质而局部较均质的物质,在微观上具有网状结构,这是其吸水保水的物理结构。保水缓释氮肥所吸持的水分主要以有效性很高的自由水和束缚水存在,占其总持水量的95%,而有效性差的结合水含量低于5%。7d水溶出率养分占总养分的77%,具有延缓养分释放功能。【结论】保水缓释氮肥是具有养分缓释和保水功能的新型保水缓释氮肥。

[Objective] A research was conducted on the characterization and performance of water-absorbent slow release nitrogen fertilizer （WASRNF）, which was prepared by chemical polymerization, physical, chemical methods. [Method] Investigation, interpretation and measurement were done with infrared spectroscopy （IR）, scanning electronic microscopy （SEM）, differential scanning calorimetry （DSC） and thermogravimetry analysis （TGA）. [Result] The water absorbency and nitrogen analysis of WASRNF was 103 g·g^-1 and 30%, respectively, and WASRNF exhibited neutral in pH and had very low salt index. WASRNF was a copolymer of nitrogen fertilizer and water-absorbent material by hydrogen bond association. There were many hydrophilic groups, a chemical mechanism to absorb and retain water. WASRNF swelled and did not dissolve in water. WASRNF exhibited whole heterogenous and locally homogenous network structures from the viewpoint of microscope. The network structure physically absorbed and retained water. The water retained in WASRNF existed as a free and a freezing water state, accounting for more than 95% water retained in WASRNF. Non-freezing water accounted for less than 5%. The nutrient solution rate WASRNF in 7 days of water accounted for 77% of total nutrient content. [Conclusion] WASRNF, water-absorbent slow release nitrogen fertilizers, showed the double function that delays nitrogen release and stores water in it.