可降解型包膜缓释肥料膜材料制备及其性能的研究

发布时间：2018-03-18 23:20

  本文选题：膜材料　切入点：聚乙烯醇　出处：《沈阳农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：养分控释效果好、可降解的膜材料是当前包膜缓释肥料领域研究的热点问题之一。本文采用聚乙烯醇为主要原料,草酸、海藻酸钠、壳聚糖、二氧化硅为改性剂,利用化学合成的方法研制了包膜缓释肥料用的改性聚乙烯醇膜材料。通过对膜材料的吸水率、应力和伸缩率等指标的测定分析,明确膜材料的改性条件；利用傅里叶红外光谱和扫描电镜,阐明膜材料改性机理和降解性能。研究结果如下：(1)草酸、海藻酸钠、壳聚糖三种改性剂均能使膜材料的应力降低,但并不存在明显的差异；三种改性剂也均能使膜材料的伸缩率增大,其中海藻酸钠改性剂的效果最佳；以吸水率为主要参考指标,草酸和壳聚糖为改性剂制备的改性聚乙烯醇膜材料,可以显著降低其吸水率,并且工艺条件为聚乙烯醇浓度55g/kg,草酸浓度32g/kg,反应温度90℃,反应时间2.5h时制备的草酸改性聚乙烯醇膜材料吸水率最低,最适合制备膜材料。(2)向改性聚乙烯醇中添加无机物二氧化硅之后,其吸水率进一步降低,特别是本身吸水率较高的处理,吸水率降低越明显；应力和伸缩率也有降低的趋势。(3)红外光谱分析结果表明,膜材料经过改性或添加二氧化硅之后,其主要吸收峰峰值大小和透射率发生明显的变化,说明改性剂、二氧化硅均能与聚乙烯醇发生反应,得到了目标产物,并且使得膜材料的结构和性能发生了变化。(4)通过质量变化、红外光谱和膜材料表面微观结构的分析,得到相同膜材料经过不同的培养方式后,降解率不同；而在同一种培养方式下不同的改性膜材料的降解率也不同。其中降解率最大的是草酸改性聚乙烯醇膜材料,其值为37.8%。添加适量的二氧化硅可以提高壳聚糖改性膜的降解率,但是会降低草酸、海藻酸钠改性膜的降解率。总之,聚乙烯醇通过草酸、海藻酸钠、壳聚糖以及二氧化硅改性后性能发生了变化,在环境中的降解能力也增强,根据不同的要求,合理地控制工艺条件,可以用来制包膜材料。
[Abstract]:In this paper, polyvinyl alcohol was used as the main raw material, oxalic acid, sodium alginate, chitosan, silica as modifier. The modified polyvinyl alcohol membrane material for coated slow-release fertilizer was prepared by chemical synthesis. The modification conditions of membrane material were determined by measuring and analyzing the water absorption, stress and expansion rate of membrane material. Fourier transform infrared spectroscopy and scanning electron microscope were used to elucidate the modification mechanism and degradation performance of the membrane material. The results are as follows: 1) oxalic acid, sodium alginate and chitosan can reduce the stress of the membrane material, but there is no obvious difference. The three modifiers can also increase the expansion rate of membrane materials, among which the sodium alginate modifier is the best, and the modified polyvinyl alcohol membrane material prepared by oxalic acid and chitosan as the main reference index is the water absorption rate, and the modified polyvinyl alcohol membrane material is prepared with oxalic acid and chitosan as modifiers. The water absorptivity of the modified PVA membrane was decreased significantly under the conditions of 55 g / kg PVA concentration, 32 g / kg oxalic acid concentration, 90 鈩，

本文编号：1631786