【作者】 宋丹；

【导师】 李凤生；

【作者基本信息】 南京理工大学 ， 材料学， 2009， 博士

【摘要】 核壳结构微纳米粒子具有不同于或优于单组分的性能,可以实现人们在纳米尺度对粒子结构、性能的设计和优化,一直是新材料领域的研究热点。将核壳粒子中的核体去除所得到的中空结构粒子具有比表面积大、密度低及表面渗透性好等特点,在很多高新技术领域具有广阔的应用前景。目前关于微纳米核壳结构粒子的制备与性能研究较多,但以聚合物为核的核壳结构粒子的系统性研究较少。鉴于微纳米核壳及中空结构粒子的巨大发展潜力,论文以聚合物/金属核壳结构复合微球的制备为切入点,开展了这两种结构粒子的制备方法与性能的研究,为新型结构微纳米粒子的制备及应用研究提供了实验和理论依据。本文的主要研究内容如下:（1）聚合物微球的制备研究聚合物微球具有制备方法简单、形貌可控性强等优点,是制备核壳结构复合粒子的良好基体。论文对形貌可控微米级聚合物微球的制备方法进行了研究,通过对合成因素的分析,确定了最佳工艺条件,制备了形貌可控的微米级聚合物微球,为后续的研究提供良好的基体。首先采用分散聚合法制备聚合物微球:讨论了反应体系中单体浓度、引发剂用量、稳定剂用量、溶剂极性、温度、聚合时间以及共聚单体配比等因素对产物形貌、粒径大小和粒径分布的影响,确定了最佳实验配方,制备了出了粒径较小的微米级PS、P（St-MMA）微球;然后以分散聚合法制备的PS微球为种子微球,进行种子溶胀聚合,通过对反应体系中单体浓度、引发剂用量、稳定剂用量、溶剂极性和温度等因素分析,确定了最佳工艺条件,制备出了平均粒径约为7μm、表面光滑、单分散性好的PS微球。（2）聚合物/金属核壳结构粒子的制备及性能研究化学镀是制备核壳结构粒子的重要方法,惰性聚合物微球化学镀的关键技术在于对其表面的预处理。论文通过对聚合物表面预处理方法的研究,提出了一种简单、有效的直接活化法。分别采用传统敏化-活化法和直接活化法对微球进行了“活化”处理在微球表面引入了Pd催化活性中心,为后续化学镀提供了条件;对聚合物微球表面化学镀镍的影响因素进行了分析,通过对实验条件的调控,可以制备出包覆层形貌可控、分散性好的PS/Ni核壳结构微球;对所制备的几种聚合物/金属核壳结构粒子的应用方向进行了探索:分别讨论了纳米PS/Ni复合微球对AP的催化作用、Au/Ni/PS复合微球的导电性能、纳米Pd/PMMA复合微球对Heck反应的催化作用及PS/Ni复合微球的磁性能。结果表明,以聚合物为核体的复合粒子在电、磁和催化等领域具有广阔的应用前景。（3）中空结构粒子的制备及性能研究研究了聚合模板法制备中空粒子的可行性:以PS/Ni核壳粒子为前驱体,分别采用煅烧、溶解聚合物核体的方法制备出了中空结构粒子。鉴于聚合物模板法过程繁琐,本文提出了一种制备中空结构金属粒子的新方法,即“氢氧化物模板法”。该方法以金属氢氧化物（Ni（OH）₂、Co（OH）₂）为模板,以化学镀为沉积手段在模板表面包覆一层合金,然后采用合适的络合剂对模板进行消融,制备出了微纳米级中空结构的Ni-P、Ni-B、Co-B非晶态粒子。与其他制备中空结构粒子的方法相比,氢氧化物模板法具有工艺简单、反应迅速、普适性强等特点,可以制备多种金属或金属合金空心粒子。研究了中空粒子对AP热分解的催化性能,结果表明:该结构的粒子可显著降低AP高温热分解峰的峰温,对AP的热分解有显著的催化效果。更多还原

【Abstract】 The capability of micro-nanometer particles with core/shell structure are different from or better than that of the core or shell single compounents. The preparation of core/shell particles can realize the design and optimization of the structure and properties of particles, and it is the attractive topic in material areas. Hollow particles obtained by removal of the core have widely potential applications in high-technology fields because they have large specific surface areas, low density and well permeability. The preparation and properties of core/shell micro-nanoparticles had been studied, but systemic researches on the core/shell micro-nanoparticles with polymer as core were fewer.In view of the great development potential of micro-nanometer particles with core/shell and hollow structure, we researched the preparation of polymer/metal core/shell particles in micrometer. Regarding this as cutting point, the preparation and properties of particles with these two novel structures are investigated. The research will provide the experimental and theoretical basis of the preparation and application of particles with novel structure. The main contents of the research are described as follows:（1） The preparation of polymer microspheresThe polymer microspheres have the merits of simple preparation process and controllable morphology, which are the good substrate used for the preparation of core/shell composite particles. The preparation methods of polymer microspheres with controllable morphology were discussed. The influencing factors of preparation process were studied, and the optimal technical conditions were determined. The polymer microspheres with narrow distribution and controllable morphology were obtained, which provided good substrate for the subsequent research.Firstly, the polymer microspheres were prepared by dispersion polymerization. The effects of the influencing factors on the morphology, particle size and size distribution of the polymer microsphere were discussed, such as the monomer concentration, the initiator dosage, the stabilizer dosage, the solvent polarity, the polymerization temperature, reaction time, and the proportion of monomers. The best experimental formulation were determined, and the polymer （PS and P（St-MMA）） microspheres with small particle size were prepared at the best experimental formulation. Then the PS microspheres prepared by dispersion polymerization were used as seed microspheres for seed swelling polymerization. The influencing factors in preparation process were analyzed, and the best technical conditions were determined. Then the PS microspheres with uniform particle size （7μm）, slick surface and good monodispersity were obtained.（2） The preparation and properties of polymer/metal core/shell particlesElectroless plating is an important method for preparing particles with core/shell structure. The surface pretreatment is the key technique of electroless plating of inertia polymer microspheres. The surface pretreatment methods of polymer were studied, and a simple and effective method called "direct-activation" was put forward. The polymer microspheres were pretreated by sensitization-activation and direct-activation, respectively. The Pd catalytic active sites were adhibited on the surface of microspheres, which provided conditions for subsequent electroless plating. The influencing factors of electroless nickel plating of microspheres were analyzed, and PS/Ni core/shell microspheres with controllable coverage morphology and good dispersibility were prepared by controlling the experimental conditions.The application of polymer/metal core/shell microspheres was explored. The catalytic effects of PS/Ni microspheres on the thermal decomposition of AP, the conductive properties of Au/Ni-P/PS microspheres, the catalytic effects of the Pd/polymer microspheres on the Heck reaction, and the magnetic properties of Ni/PS microspheres were studied in this dissertation. The results showed that the composite microspheres with polymer as cores had good application prospects in the above-mentioned fields.（3） The preparation and properties of hollow particlesThe feasibility of using polymer as template to prepare hollow particles was studied. Hollow particles were prepared by calcining and dissolving the the polymer core of the PS/Ni core/shell microspheres, respectively.In view of the complicated process of the method mentioned above, a novel method named "hydroxide template method" was proposed to prepare hollow particles. In this method, using metal hydroxide （M（0H）2） colloids as templates, electroless plating was carried out on the surface of M（0H）2 colloids to prepare M（OH）₂-M core/shell composite particles, and controllable Ni-P, Ni-B and Co-B hollow amorphous particles in micro-nanometer were obtained by adding complexing agent to dissolve the core. Compared with other methods, this method was simple and controllable, which could be extended to obtain other metal or alloy hollow particles. Then the catalytic properties of hollow particles on the thermal decomposition of AP were studied. The results showed that the hollow particles could decrease the high decomposition peak temperature evidently, showing good catalytic properties on the thermal decomposition of AP.更多还原