【作者】 程佳佳；

【导师】 袁孝友；

【作者基本信息】 安徽大学 ， 无机化学， 2011， 硕士

【摘要】 本论文针对纳米二氧化硅(SiO2)、聚四氟乙烯(PTFE)和纳米碳化硅(SiC)等粉体在实际应用中易团聚,难分散的难题,根据它们各自特点,采用不同的分散方法,探索最佳分散条件,扩展其应用,以发挥它们的纳米效应。用原位聚合法制备纳米SiO2/丙烯酸酯复合乳液。以纳米SiO2硬度高、耐磨损、透光性好等特性,提高纳米SiO2/丙烯酸酯复合乳液膜耐磨性和透光率。纳米SiO2粉体表面含有大量硅羟基,具有亲水性,与有机相的相容性不好,为解决纳米SiO2与聚合物乳液的相容性,采用高压剪切分散法直接将纳米SiO2分散在甲基丙烯酸甲酯,丙烯酸丁酯和丙烯酸中,再经原位聚合制得纳米SiO2/丙烯酸酯复合乳液。探索了实验最佳配方,研究了最佳乳化剂配比对乳液稳定性的影响,讨论了纳米SiO2用量对单体转化率和涂膜耐水性的影响。利用FTIR、TGA、UV-VIS、TEM、DLS等对复合乳液进行分析、表征。结果表明：高压剪切分散原位聚合法可有效阻止SiO2纳米粉体团聚,且SiO2纳米粒子分散均匀。当SiO2添加量占单体总质量5%时,非离子型乳化剂(OP-10)与阴离子型乳化剂十二烷基苯磺酸钠(SDBS)质量比为2：1时,单体转化率、乳液稳定性及乳液成膜后热稳定性均最佳。聚四氟乙烯(PTFE)热稳定性高,自润滑性好,纳米SiC硬度高、耐磨、耐腐蚀。在化学镀镍工艺中,添加PTFE微米粉体和纳米SiC粉体,获得减摩、耐腐复合镀层用于工业模具。研究了不同表面活性剂以及不同分散方式对PTFE、SiC在镀液中分散的影响；并对Ni-P-PTFE、Ni-P-SiC复合镀层的成分、结构及性能进行研究。结果表明：主盐浓度一定时,提高温度和pH值均能提高化学镀镍沉积速率,但温度高于90℃、pH值大于5.0时,镀液稳定性下降。Ni-P-PTFE、Ni-P-SiC复合镀层匀为非晶态结构。在超声分散和表面活性剂共同作用下,PTFE微米粉体和纳米SiC粉体可以在镀液中均匀分散,稳定时间可以达到3小时；盐雾试验表明：Ni-P-SiC复合镀层耐腐蚀性比相同厚度的Ni-P镀层强得多。相同厚度的Ni-P-PTFE复合镀层耐腐蚀性比Ni-P镀层耐腐蚀性略差,但Ni-P-PTFE复合镀层自润滑性好,可用于各种橡胶模具镀层。更多还原

【Abstract】 This thesis is mainly dealt with the aggregation of SiO2, PTFE and SiC powders in applications. According to their respective features, the different disperse methods are used to explore the dispersing conditions and extend their applications, so that their nano-effects are used.Nano SiO2/acrylates composite latex was prepared by in-situ polymerization. The membrane resistance and euphotic rate of nano SiO2/acrylates hybrid emulsion have been improved because of the high hardness, light quality properties of the nano SiO2. Nano SiO2 powders are hydrophilic with bad organic phase compatibility due to a lot of silicon hydroxyl on their surface. To solve the compatibility of nano SiO2 and polymer emulsion, SiO2 nano powder is dispersed in the mixture of methyl metharcrylate, butyl acrylate and acrylic acid with high pressure shearing homogenizer (HPSH), and then, nano SiO2/acrylic ester emulsion is synthesized via in-situ polymerization. The best experimental formula has been explored. The influence of the ratio of OP-10 to sodium dodecyl benzene sulfonate (SDBS) for the stability of the emulsion is discussed, and the conversion rate of the monomer and the water resistance related to the additive amount of nano SiO2 are dealt with. Nano SiO2/acrylic ester emulsion is characterized using TGA、UV-VIS and TEM, respectively. The results indicate that the HPSH is effective in improving the agglomeration of SiO2 nano powder and the SiO2 nano powder can be uniformly dispersed in the process of polymerization. When the additive amount of SiO2 is 5% (ratio of mass) and the ratio of OP-10 to SDBS is 2:1 (ratio of mass), the monomer conversion, the stability of nano SiO2/acrylic ester emulsion and the thermal stability for the film of nano SiO2/acrylic ester emulsion are all perfect.Polytetrafluoroethylene (PTFE) possesses thermal stability and good self-lubricity, while nano SiC possesses high hardness, excellent wear and corrosion properties. In the chemical nickel plating technology, PTFE microns powders and nano SiC powders are added to obtain antifriction and decay resistance composite coating for industrial mold. The effects of different surfactant and different scattered ways on PTFE and SiC scattered in the plating are studied, and the compositions, structures and properties of Ni-P-PTFE, Ni-P-SiC composites coating were also investigated. The results show that the increase of temperature and pH value all can improve chemical nickel deposition rate at the certain concentration of main salt, but solution stability decline at higher temperatures than 90℃, pH value more than 5.0. The structure of Ni-P-PTFE, Ni-P-SiC composite coatings are amorphous. The PTFE microns powders and nano SiC powders can be dispersed homogeneously in the plating by using ultrasonic dispersing and surfactant, and the stable time can reach 3 hours. Salt spray test shows that the corrosion resistance Ni-P-SiC composite coating much better than that of the same thickness Ni-P coating. The corrosion resistance of Ni-P-PTFE composite coating is slightly less than that of the same thickness Ni-P coating, but Ni-P-PTFE composite coating possesses excellent self-lubricity, which can be applied to various rubber mold coating.更多还原