【摘要】 以聚乙烯为主要膜材料,采用喷雾相转化法和流化床设备制备控释肥料。系统研究聚合物溶液质量分数、低密聚乙烯(LDPE)与线性低密聚乙烯(LLDPE)配比、溶剂对制备包膜尿素释放期的影响。结果表明,包膜液质量分数从5%增加到8%,包膜尿素释放期由20 d增加到173 d,说明包膜液质量分数增加对释放期延长有显著影响;LDPE/LLDPE质量比从1增加到3,控释尿素释放期从98 d减少到32 d,说明聚乙烯分子的线性结构对释放期影响显著;质量分数控制在7%时,使用四氯乙烯、正辛烷、十氢化萘和环己烷4种溶剂处理的包膜肥养分释放期在87—108 d之间,4种不同溶剂对释放性能没有显著影响。为了制备释放期适宜的包膜肥料,包膜液质量分数宜控制为7%,不同线性聚乙烯混用能改变包膜控释肥料的控释性能,上述4种溶剂均可以用来配制包膜液。更多还原

【Abstract】 Controlled-release fertilizer was made with polyethylene as main membrane material by phase inversion method and fluidized bed.The effects of components and mass fraction of different polymer solutions,the ratio of low density polyethylene(LDPE) to linear low density polyethylene(LLDPE) and solvents on the release characteristics of coated-urea were investigated systematically.The results show that as the mass fraction of polymer solution is increased from 5% to 8%,the release duration of N coated-urea increases from 20 d to 173 d;as the mass ratio of LDPE to LLDPE increases from 1 to 3,the release duration of N coated-urea decreases from 98 d to 32 d,which indicates that the mass fraction of polymer solution and molecular structure of polyethylene significantly affect the release characteristics.When the mass fraction of polymer solution is controlled at 7%,the release duration is from 87 d to 108 d for fertilizer treated with four different solvents such as tetrachloroethylene,normal octane,naphthane and cyclohexane,which shows there is no significant effect on the release characteristics.All the results indicate that in order to improve the release characteristics of controlled-release fertilizer,the mass fraction of polymer solution should be 7% and different mass ratio of LDPE and LLDPE should be adopted,and any one of the above four solvents can be used for preparing the solution.更多还原