聚合物结构对尿素缓释性能的影响研究
发布时间：2019-06-06 20:08
【摘要】：世界人口数量的剧烈增长使得对粮食的需求加大,大量使用化肥以提高粮食产量成为人们的选择之一。然而传统化肥利用率低,肥料的过度使用对环境产生较大危害,为解决这些问题,急需开发出新型肥料,缓控释肥是其中的研究热点。聚合物包膜型缓控释肥的缓控释效果同聚合物的结构息息相关,本论文主要从包膜聚合物的结晶度、亲疏水性、链柔顺性这三方面出发,研究了其对尿素缓释性能的影响。本论文的主要内容有：(1)研究了结晶度对尿素缓释性能的影响：以聚乳酸为研究对象,采用不同的方法成膜,发现以200目尼龙滤布为支撑流延制得的膜无明显孔洞,形貌较好。通过控制热处理的时间与温度,得到了具有不同结晶度的聚乳酸膜。采用自制肥料释放测定装置测定尿素通过不同结晶度膜的释放情况,发现结晶度越大,尿素累积释放率越小。将尿素累积释放率曲线进行拟合,得到形同Qw=a*tb+6.64334×t0.79776的方程,拟合后得到与结晶度X相关的a、b值；再以X为横坐标,分别以a、b为纵坐标,绘制曲线图,将曲线进行拟合,得到a、b与X的关系式分别为a=-0.07148X一3.30037:b=1.71998*10-4X3-0.01382X2+ 0.38051X-3.05255.(2)研究了亲疏水性对尿素缓释性能的影响：以甲基丙烯酸正丁酯为主要单体,引入不同含量的羟基与羧基,聚合后制备成膜,尿素缓释实验结果表明,羟基和羧基的引入均使尿素累积释放率变大；当羟基与羧基含量相同时,羧基的引入更有利于尿素的释放；同一基团的含量越大,尿素累积释放率越大；聚合物膜亲水性的增加有利于尿素的释放。改变聚合物的亲疏水性可以达到不同的缓释效果。(3)研究了链柔顺性对尿素缓释性能的影响：合成了带不同含量的羟基、羧基、酯基、苯环等的丙烯酸酯类聚合物,侧基的不同使聚合物具有不同的链柔顺性。实验结果表明,丙烯酸酯类聚合物的侧基越长,尿素累积释放率越大；侧基体积越大,尿素累积释放率越小；相对于单取代,对位非对称取代不利于尿素的释放；聚合物链柔顺性越好,尿素累积释放率越大。改变聚合物的柔顺性可以控制尿素的释放速率。
[Abstract]:With the rapid growth of the world population, the demand for food has increased, and the use of chemical fertilizers to increase grain production has become one of the choices. However, the utilization rate of traditional chemical fertilizer is low and the overuse of fertilizer is harmful to the environment. In order to solve these problems, it is urgent to develop a new type of fertilizer, and slow and controlled release fertilizer is one of the research hotspots. The sustained and controlled release effect of polymer coated slow release fertilizer is closely related to the structure of polymer. In this paper, the effect of polymer coated slow release fertilizer on urea sustained release performance was studied from three aspects: crystallinity, hydrophilicity and chain compliance of coated polymer. The main contents of this paper are as follows: (1) the effect of crystallinity on the sustained release properties of urea was studied: taking polylactic acid as the research object, the films were formed by different methods, and it was found that there were no obvious pores in the films prepared with 200 mesh nylon filter cloth as the support. The morphology is good. Polylactic acid films with different crystallinity were obtained by controlling the time and temperature of heat treatment. The release of urea through different crystallization films was measured by a self-made fertilizer release measuring device. It was found that the greater the crystallization degree was, the smaller the cumulative release rate of urea was. The cumulative release rate curve of urea was fitted, and the equation of Qw=a*tb 6.64334 脳 t 0.79776 was obtained, and the a and b values related to crystallization X were obtained after fitting. Then take X as the horizontal coordinate, take a, b as the longitudinal coordinate, draw the curve diagram, fit the curve, get a, The relationship between b and X is a 鈮，
本文编号：2494565
[Abstract]:With the rapid growth of the world population, the demand for food has increased, and the use of chemical fertilizers to increase grain production has become one of the choices. However, the utilization rate of traditional chemical fertilizer is low and the overuse of fertilizer is harmful to the environment. In order to solve these problems, it is urgent to develop a new type of fertilizer, and slow and controlled release fertilizer is one of the research hotspots. The sustained and controlled release effect of polymer coated slow release fertilizer is closely related to the structure of polymer. In this paper, the effect of polymer coated slow release fertilizer on urea sustained release performance was studied from three aspects: crystallinity, hydrophilicity and chain compliance of coated polymer. The main contents of this paper are as follows: (1) the effect of crystallinity on the sustained release properties of urea was studied: taking polylactic acid as the research object, the films were formed by different methods, and it was found that there were no obvious pores in the films prepared with 200 mesh nylon filter cloth as the support. The morphology is good. Polylactic acid films with different crystallinity were obtained by controlling the time and temperature of heat treatment. The release of urea through different crystallization films was measured by a self-made fertilizer release measuring device. It was found that the greater the crystallization degree was, the smaller the cumulative release rate of urea was. The cumulative release rate curve of urea was fitted, and the equation of Qw=a*tb 6.64334 脳 t 0.79776 was obtained, and the a and b values related to crystallization X were obtained after fitting. Then take X as the horizontal coordinate, take a, b as the longitudinal coordinate, draw the curve diagram, fit the curve, get a, The relationship between b and X is a 鈮，
本文编号：2494565
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