论文标题:淀粉接枝高吸水性树脂的合成及应用研究
Synthesis and Application Research of Starch Graft Superabsorbent Resin
论文作者 胡湘渝
论文导师 刘代俊,论文学位 硕士,论文专业 化学工程与工艺
论文单位 四川大学,点击次数 128,论文页数 100页File Size4969k
2003-04-27论文网 http://www.lw23.com/lunwen_284757927/ 高吸水树脂,接枝共聚,溶液聚合,分子模拟,包膜尿素
superabsorbent,grafting copolymer,solution polymerization,molecular simulation,coated urea
淀粉接枝高吸水性树脂是一种含有亲水基团的新型高分子网状聚合物材料，具有极强的吸水性能，其产品具有广泛的用途，现已渗透到农业、石油工业、医药卫生等各个领域。本文以淀粉接枝高吸水树脂为对象，系统地研究了它的制备方法、形态结构特征、与水相互作用机理及包膜尿素应用初探效果等，为高吸水树脂的应用研究开辟了新的途径。 论文研究了高单体浓度溶液聚合法合成高吸水树脂的工艺条件，得出淀粉预处理方式，淀粉与单体用量，共聚单体组成，中和液pH值，引发剂用量，交联剂的种类及用量，及后处理工艺等因素对高吸水树脂吸液性能的影响规律；进一步通过正交实验，最后得到试验体系下的最佳工艺参数(wt％)：丙烯酰胺58.2％，丙烯酸29.7％，淀粉11.9％，引发剂过硫酸钾(KPS)0.15％，交联剂N，N′-亚甲基双丙烯酰胺(MBA)3.5×10~(-3)％，中和液pH值6.4。在此条件下，所得树脂吸去离子水435.6g／g，吸0.9％NaCl溶液量85.3g／g。研究了在原合成体系基础上，加入适量的添加剂，发现可以改善树脂的抗电解质性能。 采用分子模拟技术，用分子动力学方法研究了高吸水树脂链段与水的相互作用，发现分子体系在模拟范围内表现出很强的分子扩张性，从而在宏观上影响树脂吸水率的变化，与Flory研究的吸水机理在离子排斥引起分子扩张阶段具有一定的相似性；为高吸水树脂吸水机理的理论研究提供了新的研究方法和手段。使用红外光谱、热分析和扫描电镜分析了合成高吸水树脂的形态与结构，四川大学硕士学位论文认为高吸水树脂的热稳定性良好，发现共聚单体的组成对高吸水树脂的分解温度和表面形貌结构特征都存在较大影响。 最后，本文进行了高吸水树脂包裹尿素的初步应用研究，将树脂溶液作为包膜材料，直接施用于尿素的缓释系统，成功地使普通尿素具有一定的缓释性能，为有效的开发缓释肥料拓展了道路。
Starch graft superabsorbent resin is a kind of new macromolecular network polymer materials, which contains hydrophilic groups and therefore can absorb a large amount of water. Superabsorbents are widely used in various fields such as agriculture, petroleum industry, medicine and hygiene. This paper describes the means of systematic study on the preparation process, morphology and structural characterization, and the mechanism of the action of water on copolymers as well as the effect of the coated urea. As a result, it opens up a new path for the application research of superabsorbents.Starch graft superabsorbents can be prepared by the solution of polymerization at high monomer concentration. The influence of several technological conditions to the swelling properties of these absorbents has been investigated as following: the method of the starch pretreatment, the component of comonomers, pH of the neutralization, contents of the starch or monomer, initiator, crosslinker, and the post treatment. Further more, through the ortho-experiment, the optimum process parameters in this experiment system are obtained(wt%): acrylamide58.2%, arcyl acid29.7%, starch11.9%, initiator potassium ammonium persulfate (KPS)0.15%, crosslinking agent N,N " -methylene-bis-acrylamide (MBA)3.5 × 10-3%. Under these conditions, resin absorbency with distilled water and a saline solution (0.9%NaCl) is 435.6g/g and 83.5g/g, respectively. Study also finds that if properamount of additive is added to the preparation system, the anti-electrolyte of absorbents would be improved.As a wonderful application of molecular simulation, the molecular dynamics method is used to research the action of water on polymer chains. It is discovered that molecular system reprents strong tendency to expand the network. Therefore, the expanded molecular would effect the water absorbency macroscopically. The results are in conformity with the Flory"s network theory. The computer simulation offers a new research method and means for the study of the theory of the absorbing water mechanism. The copolymers are characterized by IR spectroscopy, thermal analysis and scanning electronic microscopy (SEM). It proves to be a better thermal stability, and the component of comonomers influences the resin"s decomposition temperature and surface morphological characterization notably.Finally, the starch graft superabsorbents are applied to coat the surface of urea so as to form a slow releasing urea. The coated materials can play an important role for controlling nutrient release. The preliminary experiment result develops an effective way to produce release fertilizer.
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