【作者】 朱岩；

【导师】 孙多先；

【作者基本信息】 天津大学 ， 应用化学， 2004， 博士

【摘要】 本文采用自乳化法制备的聚氨酯离聚体在水中能自组装形成两亲性的纳米粒子，以此作为纳米胶囊对固体、液体进行包埋，在位生成具有核壳结构的阴离子型聚苯乙烯/聚氨酯（PS/PU）、阳离子型二氧化硅/聚氨酯（SiO2/PU）纳米复合物水分散液，后者属于创新性成果。系统地研究了水性聚氨酯及其纳米复合物的结构和性能，建立了其结构和相分离的表征技术。非交联型纳米复合物水分散液粒子的粒径较小，在纳米级范围内，具有较窄的、连续的粒径分布；具有明显的核壳结构，且呈规整的球形。交联型纳米复合物水分散液粒子粒径较大，分布较宽；粒子形态偏离球形。交联类型不同，对水分散液粒子形态的影响也不同。纳米复合物中核、壳之间的质量比对其性能如粒径及其分布、粘度、电导率、紫外吸光度及对热稳定性都有很大的影响。对苯乙烯在阴离子聚氨酯纳米胶囊内的本体聚合过程进行了研究，苯乙烯单体是增溶在聚氨酯纳米胶囊内并直接发生非均相聚合的，当苯乙烯单体浓度增大到一定程度（核壳比为60:100）时，由于体系中聚氨酯的相对量减少，乳胶粒表面的覆盖率降低，粒子不稳定而发生聚并。阳离子聚氨酯、未交联型SiO2/PU纳米复合物都呈无定型状态，交联型SiO2/PU纳米复合物有一定结晶生成，其晶面间距为d(A)=3.87和3.58nm，属于二氧化硅的立方晶型。纯聚氨酯表面以硬段为主，硬相段中存在一定的短程有序结构，软、硬段之间有一定的相混合；核的引入并随着核壳比的增加，非交联型纳米复合物的粒子表面主要以硬段为主，软、硬段之间相分离加剧的同时，壳层PU的硬段相中短程有序区的氢键也有所破坏；交联结构对软、硬段之间的相分离产生更大的影响，但对硬段相中短程有序区的氢键的影响与交联结构的类型有关。创新性地把SiO2/PU纳米复合物水分散液应用于汽车电泳漆的主要原料水性环氧树脂（ER）外观和性能的改性中；SiO2/PU纳米复合物粒子不仅可以均匀分散在水性环氧树脂中，同时也可促进ER粒子在水中的分散，减少聚并。SiO2/PU纳米复合物的加入对ER起到了同步增韧、增强的效果。更多还原

【Abstract】 In this paper, polyurethane ionomers including amphipathic nanoparticles were prepared by self-emulsifying method. The nanoparticles were used to encapsule a solid or liquid, thus anionic polystyrene/polyurethane (PS/PU) and cationic silicon dioxide/polyurethane (SiO2/PU) nanocomposites dispersions of core-shell type were prepared in-situ. The later are innovative result. The structure-property relationships of polyurethane ionomers and their nanocomposites were studied carefully and a series of analytical methods were established to investigate the structures and phase separations of them.Uncross-linked nanocomposites dispersions presented narrow and continuous particle size distribution, whose mean particle sizes were of nanometer dimension. Obvious core-shell structure could be seen in the particles. The core/shell ratios had a affection on particle sizes, viscosities, conductivities, absorbance and thermal stability. The cross-linked structure affected the particle morphology and properties also.The bulk polymerization process of styrene was studied, that indicated that styrene was cosolvent in anionic polyurethane nanocapsules and heteroazeotropic polymerization occurred directly. When core/shell ratio was higher than 60:100, there were particle’s aggregations of some degree. Cationic polyurethane and uncross-linked SiO2/PU nanocomposites were of amorphous phase, however, cross-linked SiO2/PU nanocomposites had crystallinity. d(A)=3.87, 3.58nm indicated that it was cubic system of silicon dioxide.There were more hard segments on the surface of polyurethane and phase mixing between soft and hard segments. The existence of cores and cross-linked structure between core and shell made much effect on the phase behavior of the nanocomposites. It could be found that the physical properties of electrophoresis membrane of epoxy resin were improved by SiO2/PU nanocomposites. Intensity and flexibility of epoxy resin membranes were increased simultaneously.更多还原