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采用小麦秸秆液化产物制备包膜尿素。通过正交实验对影响控释性能的5个因素进行了研究,采用ATR-FTIR、SEM分别对液化和包膜过程的物料、膜层的微观形态进行了表征。结果表明,小麦秸秆液化产物制备包膜尿素的最佳配方为:液化剂聚乙二醇400与丙三醇的质量比为130∶20,催化剂三氧化钨和硫酸的质量比为0.22,吐温的质量为0.5 g,乙二胺在组合多元醇中的质量分数为2.2%,多亚甲基多苯基多异氰酸酯(PAPI)与组合多元醇的质量比为1.9。小麦秸秆液化产物富含羟基,且结构中包含了麦秆分解产物,液化产物和PAPI在尿素表面反应生成了聚氨酯膜,膜层致密均一,对尿素控释效果良好。
Coated urea was prepared by using wheat straw liquefaction product. Five factors that affect the performance of controlled release were studied by orthogonal experiments. The microstructure of the material and membrane was characterized by ATR-FTIR and SEM respectively. The results showed that the optimal formula for the preparation of coated urea by the liquefaction products of wheat straw was as follows: the weight ratio of the liquefying agent polyethylene glycol 400 to glycerol was 130:20, the mass ratio of the catalyst tungsten trioxide to sulfuric acid was 0.22, 0.5 g, Ethylenediamine in the combined polyol was 2.2%, and the mass ratio of polymethylenepolyphenyl polyisocyanate (PAPI) to the combined polyol was 1.9. The liquefaction products of wheat straw are rich in hydroxyl groups, and the structure contains the decomposition products of wheat straw. The liquefied products and PAPI react on the surface of urea to form polyurethane film. The membrane layer is compact and uniform, and the controlled release of urea is good.