【作者】 杜鸿雁；

【导师】 张超灿；

【作者基本信息】 武汉理工大学 ， 材料学， 2004， 硕士

【摘要】 本论文以研究纳米二氧化硅（SiO₂）／聚氯乙烯（PVC）复合材料的结构、性能为目的，通过无皂乳液聚合的方法制备了表面高分子化的纳米SiO₂，并将其应用在PVC材料中制备了纳米SiO₂／PVC复合材料。研究了改性后纳米SiO₂对纳米SiO₂／PVC复合材料的结构与性能的影响；纳米SiO₂／甲基丙烯酸甲酯（MMA）无皂乳液聚合对纳米二氧化硅分散性的影响；不同的单体对纳米SiO₂分散液进行无皂乳液聚合对纳米SiO₂的分散性的影响，探讨了所选用的不同单体的无皂乳液聚合机理。 纳米粒子／聚合物基复合材料的性能的提高，首要条件是纳米粒子必须在聚合物基体中具有良好的分散性。由于普通的无机纳米粉体中具有一定程度的团聚现象，而在纳米SiO₂分散液中，由于双电层的存在，团聚现象是非常微弱的，并且这种团聚是一种软团聚，是可以通过某些反应热打开的。因此我们选择纳米SiO₂分散液，并对其进行无皂乳液聚合，制备出单分散的表面高分子化的纳米SiO₂，在PVC应用中更好的显现出纳米刚性粒子增韧增强的作用。 由于PMMA与PVC的相容性好，我们选用MMA为主要单体，讨论了单体用量及加料方式、反应温度、改性偶联剂用量、引发剂用量等条件对无皂乳液聚合的影响。应用IR、紫外光谱、TEM、XPS等测试手段对产物进行了表征。结果证明：经过PMMA改性后的纳米SiO₂具有良好的分散性，并且表面接枝有聚合物PMMA，为纳米SiO₂在PVC中的应用提供了保证。 本文研究了经PMMA改性后的纳米SiO₂对纳米SiO₂／PVC复合材料的结构与性能的影响。测试了复合材料的力学性能，并应用SEM、DSC等测试手段表征了纳米SiO₂／PVC复合材料的结构和性能。结果表明：纳米SiO₂的加入可以同时起到增强增韧的作用；纳米SiO₂填充量为4％时，具有最优性能；纳米SiO₂在PVC中具有良好的分散性，断裂为韧性断裂；纳米SiO₂的加入，提高了PVC材料的玻璃化转变温度（Tg）。更多还原

【Abstract】 In order to study the structures and properties of the nanosilica/PVC composite, we modified nanosilica with MMA by the emulsifier-free emulsion polymerization. The nanosilica/PVC composite was prepared. Studied the effect of nanosilica modified with MMA on nanosilica/PVC composite, the effect of the emulsifier-free emulsion polymerization of nanosilica/MMA on the dispersion of nanosilica, the effect of the emulsifier-free emulsion polymerization with others monomer on the dispersion. Studied the reaction mechanism of the emulsifier-free emulsion polymerization of others monomer.The properties of the nano-particles/polymer composite are decided by the dispersion of nano-particles. The treatment of nano-particles can contribute to the mono-dispersion of nano-fillers in the matrix and improve the strength and toughness of the composites greatly.Because of the excellent com-patibility between PVC and PMMA, we modified nanosilica with MMA by emulsifier-free emulsion polymerization. The effects of many factors, such as monomer MMA, initiator, temperature etc, on emulsifier-free emulsion polymerization were investigated. The polymeric product was analyzed by FT-IR, TEM, XPS and so on. The obtained reveal that the surface of nanosilica covered with PMMA. The nanosilica by surface treatment with emulsifier-free emulsion polymerization has nanoscale dispersion.The effect of modified nanosilica on the structures and properties of nanosilica/PVC composites was studied. The properties of the composite were sanalyzed by the SEM, DSC and so on. The obtained reveal that modified nanosilica can improved the strength, toughness and Tg of the composite greatly, nanosilica has mono-dipersipn in the nanosilica/PVC composite. The composite had the best overall mechanical properties when the modified nanosilica content was 4%.更多还原