【作者】 牟斌；

【导师】 刘鹏；

【作者基本信息】 兰州大学 ， 高分子化学与物理， 2008， 硕士

【摘要】 近年来,有机/无机纳米复合材料以其优异的性能越来越受到人们的关注,是材料领域研究的热点之一。纳米粒子表面改性可以降低粒子的表面能,改变粒子的表面极性,提高粒子与基体的亲和力,减少粒子间的团聚,促进纳米粒子在聚合物基体中的分散。对纳米粒子进行表面改性,有利于深入认识纳米微粒的基本物理效应,同时也扩大了纳米粒子的应用范围。目前,主要通过表面活性剂法,原位聚合法及表面接枝聚合等方法来改性纳米粒子。在无机微粒表面接枝聚合,可以更好地改善聚合物基体和无机填料的相容性,更有利于形成性能优良的纳米复合材料。具有特殊分子构造从而具有独特性质的超支化聚合物受到了广泛的关注,其在界面与表面科学上发挥着重要作用,可用来制造功能化的表面、界面材料。与线型聚合物相比,它们拥有良好的溶解性,低熔融黏度,大量的末端基团等。其一般可以通过AB_X型单体的缩聚反应或加成反应,自缩合乙烯基聚合以及潜在AB_n单体的开环聚合等方法来合成。应用超支化聚合物改性纳米粒子是一种新的引人关注的方法。本文采用自缩合乙烯基聚合通过原子转移自由基聚合的技术在纳米氧化硅,埃洛石纳米管表面设计接枝超支化聚合物,超支化接枝共聚物以及超支化共聚物,制备了超支化聚合物/无机杂化纳米复合材料,并以接枝有超支化对氯甲基苯乙烯的纳米氧化硅为模板制备了内径为10-40nm的聚合物空心球。1.通过连续表面引发自由基聚合在纳米氧化硅表面接枝超支化接枝共聚物利用自缩合乙烯基聚合的方法在纳米SiO₂表面成功接枝了超支化的聚对氯甲基苯乙烯,得到了接枝有超支化聚合物的纳米氧化硅（SN-HBP）;再利用其表面的活性链末端引发基团来引发甲基丙烯酸甲酯进行原子转移自由基聚合,从而制得超支化接枝共聚物修饰的纳米氧化硅（SN-HBP-PMMA）。2.通过纳米氧化硅模板表面引发自缩合乙烯基聚合制备交联聚合物纳米囊利用自缩合乙烯基聚合（SCVP）的方法在纳米SiO₂表面成功接枝了超支化的聚对氯甲基苯乙烯,得到了接枝有超支化聚合物的纳米氧化硅（SN-HBP）,将其表面聚合物链末端的卤素基团转变为氨基,与六甲撑二异氰酸酯（HDI）发生交联反应,再用HF溶液将纳米氧化硅核刻蚀,获得内径为10-40nm交联的聚合物纳米空心球。3.通过表面引发自缩合乙烯基（共）聚合在埃洛石纳米管表面接枝超支化（共）聚合物利用原子转移自由基聚合的技术,在埃洛石纳米管表面实现了2-（溴乙酰氧基）乙基丙烯酸酯（2-（（bromoacetyl）oxy）ethyl acrylate）的自缩合乙烯基聚合以及其与丙烯酸正丁酯的自缩合乙烯基共聚合,在埃洛石纳米管表面成功接枝了超支化聚合物及其共聚物。更多还原

【Abstract】 In recent years, organic/inorganic nanocomposites have attracted more and more attention and become one of the focuses in the area of materials due to excellent properties. The surface modification of the inorganic nanoparticles can reduce the surface energy of the nanoparticles, change the surface polarity of the nanoparticles, increase the affinity of the nanoparticles to the polymeric matrice, avoid aggregation of the nanoparticles and improve the dispersibility of the nanoparticle in polymeric matrice. It is helpful to understand the basic physical effects of nanoparticles, and enlarge the scope of its application. At present, the main methods of surface modification have surface reactive agent, in-situ polymerization and surface graft polymerization etc. The surface graft polymerization would further improve compatibility between the nanoparticles and polymeric matrice in order to fabricate more excellent nanocomposites.Hyperbranched polymers have attracted considerable attention because of their specific architecture, unique chemical and physical properties, and they have played a vital role in interface and surface sciences, which can be used advantageously as functional surfaces and interfacial materials. In addition, they have high solubility, low viscidity and high density of surface functional groups compared to linear analogues. Hyperbranched polymers have been synthesized in a one-pot route via self-polycondensation or an addition polymerization reaction of ABx-type monomer, self-condensation vinyl polymerization (SCVP), ring-opening polymerization (ROP) of latent AB_n monomers and so on. It is a promising route that hyperbranched polymer is used to surface-modify the nanoparticles.In this paper, hyperbranched (co)polymers modified inorganic nanoparticles and nanotubes have been prepared by self-condensing vinyl polymerization via surface-initiated atom transfer radical polymerization technique on the surface of silica nanoparticles, halloysite nanotubes. And the crosslinked polymeric nanocapsules with inner diameter of about 10-40nm were fabricated from silica templates grafted hyperbranched PCMS.1. Well-defined hyperbranched-graft copolymer grafted silica nanoparticles by consecutive the surface-initiated atom transfer radical polymerization We prepared the well-defined hyperbranched-graft copolymer grafted silica nanoparticles (SN-HBP-PMMA) by the surface-initiated atom transfer radical polymerization of methyl methacrylate from the hyperbranched polymer grafted silica nanoparticles (SN-HBP), via the self-condensing vinyl polymerization (SCVP) of p-chloromethyl styrene.2. Preparation of crosslinked polymeric nanocapsules by surface-initiated self-condensing vinyl polymerization on silica templatesWe develop a novel method for crosslinked polymeric nanocapsules with inner diameter of about 10-40nm from the nanosilica templates grafted hyperbranched polymers with amino-terminated hyperbranched polymers by the crosslinking with hexamethylene diisocyanate (HDI) after the surface end groups had been transformed to amino groups, then the nanosilica templates were removed by HF etching to produce the crosslinked polymeric nanocapsules. The hyperbranched polymer grafted silica nanoparticles (SN-HBP) prepared by the self-condensing vinyl polymerization (SCVP) of p-chloromethyl styrene.3. Halloysite nanotubes grafted hyperbranched (co)polymers via surface-initiated self-condensing vinyl (co)polymerizationWe report a convenient method to modify the surface of HNT with a hyperbranched polymer and copolymer shell by surface-initiated self-condensing vinyl polymerization (SCVP) of 2-((bromoacetyl) oxy) ethyl acrylate (BAEA) and the self-condensing vinyl copolymerization (SCVCP) of n-butyl acrylate (BA) and BAEA via atom transfer radical polymerization (ATRP) technique.更多还原