几种聚合材料包膜尿素的研制及评价方法研究

为研究尿素养分释放特性,以有机物质(淀粉A/聚乙烯醇V)为基底材料,无机非金属矿物(硅藻土G/膨润土P/沸石粉F)为改性材料制备复合材料并包膜尿素,测定了包膜尿素的成粒率及抗压强度,采用水中溶出率法与土壤培养法探讨了包膜肥料养分的释放规律,并对两种方法的测定结果进行比较。研究结果表明:包膜尿素各粒径颗粒成粒率差异显著,3种包膜尿素中粒径3~4 mm颗粒成粒效果最好,均在60%左右,成粒效果及抗压强度均表现为AVGUAVPUAVFU,说明粘结性能表现为AVGAVPAVF。包膜肥料在水、土两介质中的养分释放率与释放期均有所不同,AVFU在水中的初期溶出率高达30%,7 d累积释放率高达75.02%,释放期仅约为11 d;AVGU与AVPU氮素释放缓释性能显著,其初期溶出率仅为12%~15%,7 d累积释放率为42.24%~58.36%,释放期约为36~44 d;而在相同培养时间内土壤中养分溶出率仅为水中的26%~57%,但释放期增长到了42~112 d。在聚乙烯醇-淀粉聚合物的基础上添加改性剂能够对膜材料的耐水性能以及缓释效果有不同程度的优化,膜材料的吸水特性很好地保证肥料养分的缓慢释放,更好地为植物的生长提供养分。

Studies on Preparation and Evaluation Method of Several Polymeric Materials Coated Urea

In order to investigate the urea nutrient releasing characteristics, this paper took organic material (starch A/ polyvinyl alcohol V) as substrate material, inorganic non-metallic mineral (diatomite G/ bentonite P/ zeolite powder F) as modified material to prepare composite material and coated urea, and measured granulation rate and compressive strength by water dissolution rate and soil incubation methods. Besides, the paper also probed into the nutrient release rule of coated fertilizer, and compared the testing results of these 2 methods. The results showed that grain yield difference was significant in each particle size of coated urea, the granulation effect was the best in particle size 3~4 mm of the 3 kinds of coated urea, which was about 60%. The granulation effect and compressive strength all expressed AVGU>AVPU>AVFU, indicating the adhesive property was AVG>AVP>AVF. The nutrient release rate of coated fertilizer in soil and water and release duration were different. The initial dissolution rate of AVFU in water was as high as 30%, cumulative release rate of 7 d was as high as 75.02%, release duration was only about 11 d. Slow release performance of AVGU and AVPU nitrogen were significant. The initial dissolution rate was only about 12%~15%, the cumulative release rate of 7 d was 42.24%~58.36%, release duration was about 36~44 d. At the same time, the dissolution rate of soil nutrients was only 26%~57%, but the release duration was increased to 42~112 d. On the basis of polyvinyl alcohol starch polymer, the water resistance and slow release effect of the membrane material could be optimized by adding modifier. The water absorption character of film material was very good for ensuring the slow release of fertilizer nutrients, and preferably providing nutrients for plant growth.