【作者】 魏晓丽；

【导师】 刘开平；

【作者基本信息】 长安大学 ， 材料学， 2008， 硕士

【摘要】 高吸水保水材料是一种吸水能力特别强,而且保水能力也非常好的特殊功能高分子材料。它是近30多年来开发的一种新型功能高分子材料,用途极为广泛,在农林、园艺、沙漠治理、医药卫生、建筑材料、日用化工、食品和环保等众多领域已成为不可或缺的材料,发挥着日益重要的作用,具有良好的市场前景。但是,传统高吸水保水材料乃至矿物/有机复合高吸水保水材料由于生产成本高、抗盐性能和保水性能差等原因,其应用范围得到了很大的限制,推广应用缓慢。本论文主要针对我国北方尤其是西北旱作农区降雨少且集中、土壤有机质含量低、保水性差的现状,以降低生产成本、简化生产工艺、提高抗盐性和保水性为出发点,采用膨胀蛭石为主要原料并对其进行表面改性的技术路线,研制了表面改性型蛭石吸水保水材料。实验表明,这样一方面大大的降低了生产成本,另一方面,材料的制备工艺简单、周期短、试验便于控制。论文研究了表面活性剂的种类及其用量对膨胀蛭石吸水性能的影响。研究表明:表面活性剂十二烷基苯磺酸钠、甲基纤维素和六偏磷酸钠对膨胀蛭石吸水性能的影响较为明显,而聚乙二醇对保水性的影响较大。且十二烷基苯磺酸钠,甲基纤维素,六偏磷酸钠的最佳用量分别为15%,10%,60%,聚乙二醇与水的用量比值的最佳值为1:4。采用XRD分析、IR分析和激光粒度分析仪测试对表面改性型蛭石吸水保水材料进行了表征。结果表明,甲基纤维素在蛭石微粒表面的吸附较好,而单独的十二烷基苯磺酸钠、六偏磷酸钠在蛭石表面的吸附量并不是太大,加入聚乙二醇后,由于聚乙二醇的增溶作用,增大了甲基纤维素、十二烷基苯磺酸钠的吸附量,使产品的保水性能增强。结合高吸水保水材料的吸水理论,初步探讨了表面改性型蛭石吸水材料的吸水机理。我们认为:膨胀蛭石在改性的过程中,表面活性剂利用其静电斥力稳定作用和空间位阻稳定作用使其亲水基首先吸附在具有亲水性的蛭石表面,亲油基外漏在外端,形成单分子层;随着表面活性剂浓度的增加,其亲油基产生团聚,形成亲油基层,而多余的亲水基又外漏于亲油基层外端,使得蛭石微粒表现为亲水性,使其具有良好的吸水性能。更多还原

【Abstract】 Super absorbents(SAP) can absorb a large amount of water compared with general water absorbing materials in which the absorbed water is hardly removable even under some pressure .It is a new-style developed functional macromolecule material in recent 30years,and it is widely used in agriculture, horticultural applications, sanitation, architecture and so on. The more important role is played in lots of fields recently and a huge market potential is forecasted. However, traditional SAP can’t be used in the large scale because of its expensive production cost, weak salt-resisting and water-holding capacity.The study is regard to the current situation in the north of China even in the northwest such as little rainfall, low soil organic content and poor water holding capacity. To reduce the production cost and simplify the production technology, the research adopts the expanded vermiculite as the main raw material and we modify its surface to get the super absorbent of surface modified vermiculite. The experiment shows that it is easy to control with simple process and short cycle.The influences of the sort of surfactants and their content on the super absorbent of surface modified vermiculite were studied .It shows that the absorption was determined as the content of sodium dodecyl benzene sulfonate (SDBS), methylcellulose (MC) and sodium hexametaphosphtte, and polyethyleneglycol (PEG) influences the material’s water holding capacity. And the results also show that SDBS of 15wt%, MC of 10wt%, sodium hexametaphosphtte of 60wt% and PEG: H2O of 1:4 are the optimal conditions.The analysis of XRD, IR and Laser Particle Size shows that MC is well absorbed on the surface of expanded vermiculite, but the absorption amount of SDBS, sodium hexametaphosphtte in the individual way is not very good .With the accession of PEG, their absorption amount is increased and the water holding capacity of the production is also enhanced.With water absorption theories of traditional super absorbent, the water-absorbing mechanics of the super absorbent of surface modified vermiculite was preliminarily researched. We found that in the process of the modification of expanded vermiculite, surfactants’hydrophobic groups are absorbed on the surface of the vermiculite with the effects of their electrostatic repulsion and steric hindrance; the hydrophilic groups are on the outside. Because of this, the super absorbent of surface modified vermiculite has the capacity of water holding.更多还原