【作者】 薛兵；

【导师】 蒋引珊； 张培萍；

【作者基本信息】 吉林大学 ， 材料学， 2011， 博士

【摘要】 本文以地开石为原料,以硅烷偶联剂、磷酸酯、油酸和硬脂酸为改性剂对地开石进行表面改性；以尿素为插层剂为地开石进行插层处理。通过分散性实验、接触角实验、X射线衍射和红外分析等手段评价了地开石表面憎水性改性效果和有机分子插层效果。并通过快速煅烧地开石插层复合物的方法制备了片层剥离的地开石粉体。在此基础上,将地开石作为填料,与聚乙烯熔融复合制备了改性地开石/聚乙烯复合物和剥离地开石/聚乙烯复合物,比较两者在力学性能、热稳定性和防腐蚀包装效果上的差别。为了提高复合物的功能性和探索多组分、多形貌功能填料在非极性体系中的界面效果、反应活性,以及不同填料间的作用效果,将铜微粉联合层状铝硅酸盐添加到聚乙烯体系中。借助X射线衍射、扫描电镜和透射电镜研究方法,分析层状铝硅酸盐和铜微粉在基体中的分布,并从结构角度研究两种填料的协同效果和对复合材料力学性能、热稳定性、抗菌性和防腐蚀包装效果的影响。初步探讨了地开石在极性橡胶体系中的作用效果。在炭化硅藻土代替部分炭黑补强的天然橡胶的体系中,少量改性地开石的加入可以显著提高橡胶基体的耐磨性更多还原

【Abstract】 Dickite is natural clay mineral.The exploitation and utilization about dickite is not enough, because the reserves are not as more as kaolinite and the distribution is not widespread. Besides some common physical and chemical properties belong to dickite and kaolinite, dickite has other advantages such as low impurity content, low water absorption, high whiteness and et al. It is an excellent filler for plastic and rubber. It is also the potential filler for preparing novel polymer/layered silicate nanocomposites. However, the reports on the applications of dickite as filler in polymer matrix are rare. Thefore, in the paper we try to use dickite as functional filler to prepare novel dickite/polymer composite and study the related properties of complexes.Silane coupling agent (KH-550), hexadecyl phosphate, oleic acid, and stearic acid (SA) was used to modify dickite and hydrophilicity of modified dickite was characterized by dispersion experiments and contact angle tests. The results indicated that hydrophilicity of modified dickite decreases sharply, compared with nonmodified dickite. The order of effective hydrophobicity modification of dickite for modifying agents is SA> OA> HP> SCA. The results of FTIR indicated that SA is chemically bonded on the surface of dickite, whereas HP, a modifying agent with poor modification effect, is physically absorbed on the surface of dickite. The results suggest that the chemical bonding between modifying agents and dickite is more beneficial than physical adsorption for the hydrophobic modification of dickite. SEM micrographs of the modified dickite/PE composites show that modified dickite with hydrophobic surface could uniformly distribute in the PE matrix, where more platelet structure parallel to the composite film surface is formed, and the anticorrosion properties of composite are greatly improved. The mechanical properties of the resultant composites displayed a fact of reinforcement of modified dickite. The particle size of dickite decreased because of the mechanical grinding process. However, the size of dickite is still more than 5μm and the as-prepared modified dickite/PE composites are still traditional microcomposite. Some obtained performance is not satisfactory. Therefore, the preparation of smaller particles even exfoliated dickite could be a new exploration direction. The dickite intercalation complex was prepared using urea molecules as a precursor for the exfoliation of dickite. The results revealed organic molecule could intercalate the layers of dickite and react with inner surface hydroxyl of dickite, leading to the formation of hydrogen bond. By the method of rapid calcination dickite intercalated composites, exfoliated dickite particles were prepared.500℃calcination rapidly decomposed interlamellar urea molecules and produced a large amount of gases, including ammonia and carbon dioxide, which expanded the dickite interlayer and led to a more complete exfoliation of the dickite. The surface modification of exfoliated dickite and the process of melt mixing combined with melt extruding had effectively inhibited the agglomeration of exfoliated dickite in PE matrix. The highly dispersed clay platelets formed a more tortuous pathway, which retarded the progress of salt spray through the composites film, and therefore, the obtained anticorrosion packing properties and thermooxidative stability of exfoliated dickite/PE composite were better than that of the modified dickite/PE composite.In order to explore the interface effect, reaction activity and interaction between multi-component and multi-functional filler, homemade copper powder and layered silicate montmorillonite were introduced into PE matrix to prepare layered silicate/copper/PE composites. The results of XRD and TEM showed that the layered silicate was exfoliated and some of the layers nearly paralleled to the composite film surface. The agglomeration of copper powder had been reduced in the PE matrix. High active copper powder could react with permeated oxygen and intercept the permeation of O2, so as to protect packaged products from corrosion. In particular, permeation of water and oxygen along the formed tortuous path way resulted in more contacts between the corrosive species and copper powder and ensured the more complete reaction. Thus, we draw the conclusion that the combination of physical barrier effect of silicate layers and chemical consumption function of copper powder had played an important role in theimprovement of the anticorrosion packing properties of PE matrix. Coexistence of the exfoliated silicate layers and the copper powder particles in PE matrix could produce a synergistic effect on enhancing the thermal-oxidative stability and mechanical performance of as-prepared composites. Furthermore, it was observed that the bactericidal ability of as-prepared composites increased with copper powder content effectively. In addition, the well dispersed silicate layers in layered silicate/copper/PE composites could hinder the release of Cu ions and improved the long-term antibacterial effect of the composites.The introduce of layered dickite into PE matrix has significantly improved the barrier properties of materials, while it may play a different role on the nature rubber system reinforced by carbonized diatomite. The results showed that the organic matter in diatomite could be translated into amorphous carbon adsorbed on the surface of diatomite and in the micropore of diatomite. Because the carbon in carbonized diatomite could improve the compatibility between diatomite and nature rubber, the introduction of carbonized diatomite into nature rubber matrix could enhance the mechanical properties. When 25 wt% carbon black was replaced with carbonized diatomite, the tensile strength and tear strength of NR vulcanizates was significantly improved. The introduce of a small amount of addition of modified dickite could prevent crack propagation, reduce the wear volume, significantly improve the wear resistance of rubber samples.更多还原