【作者】 马寒冰；

【导师】 沈嘉年；

【作者基本信息】 上海大学 ， 材料学， 2004， 博士

【摘要】 1．根据对变频电机用电磁线绝缘材料破坏过程的分析，及对纳米YiO₂、SiO₂、Al₂O₃、ZnO、MgO、Fe₂O₃、ZrO₂和BaTiO₃等无机材料作为耐变频绝缘漆改性材料的筛选实验研究，提出了添加纳米TiO₂的变频绝缘漆的设计。采用液相反应法制备上述纳米颗粒，并在有机绝缘树脂聚酰胺酰亚胺中均匀分散制备纳米无机／有机复合绝缘材料。通过XRD和TEM等测试手段研究纳米颗粒形态和结构特征，用耐高频脉冲电压实验测定纳米复合材料耐变频特性。结果表明，纳米TiO₂、SiO₂、Al₂O₃、ZnO、MgO、ZrO₂和BaTiO₃改性聚酰胺酰亚胺复合绝缘材料均能够提高电磁线的耐变频寿命，其中纳米级金红石型TiO₂由于具有较好的介电性能、热传导性能、紫外光吸收性能和适宜的导电性能而大幅度提高绝缘材料耐变频寿命，制备的新型电磁线常规性能达到国家标准GB／T6109.11-1990的要求，耐高频脉冲电压实验下的老化寿命较普通电磁线提高了7.45倍，适合于变频电机使用。新型纳米耐变频复合绝缘材料经企业试用后，反映良好，新型耐变频纳米复合绝缘材料将具有良好的应用前景。 2．以TICl₄和NaOH为原料，通过控制工艺条件制备不同粒径金红石型纳米TiO₂，通过XRD、TEM等手段对纳米TiO₂颗粒形态结构进行表征。结果表明，当NaOH浓度在5.5～13.75 mol．L^-1、反应温度高于82℃、陈化时间大于2.0h时，可以直接制备金红石型纳米TiO₂。纳米TiO₂粒子生长表观活化能在1023K分为两段，其中温度为873K～1023K时表观活化能为0.3KJ．mol^-1，1023K～1273K时表观活化能为1.4KJ．mol^-1，随着煅烧温度升高和煅烧时间的延长，纳米TiO₂晶格畸变值减小。实验制备TiO₂颗粒中TiO₂含量高达99.7％，粒径为25nm～250nm，呈纯金红石相结构。 3．采用砂磨和超声振荡对纳米TiO₂颗粒进行分散，并通过沉降性分析、粒度分布分析和颗粒重新团聚实验研究砂磨和超声工艺对纳米TiO₂颗粒分散性的影响。运用基于支持向量机算法的模式识别方法建立新的砂磨分散和超声分散数学模型，并对Pisch数学模型进行了修正。建立了评价工艺条件对超声波分散效果影响的数学模型。结果表明，纳米粒子经超声波分散后，颗粒的重新团聚情况分为三个阶段。通过砂磨／超声分散联用，将纳米TiO₂颗粒在水中的初始体积平均粒径控制在150nm以下，重新团聚到2μm的时间DIS值从32min提高到164min，纳米TiO₂在PAI中的团聚体 大小从30林m减小到50nm以下，纳米颗粒的分散性明显提高。4.采用均匀沉淀法对纳米TIO:进行无机表面改性，及溶液吸附法对纳米TIO:进行有机 表面改性，并用XPS、X盯和TG等测试手段表征纳米Tio:颗粒的形态结构;用乙 电位仪、激光粒度仪等分析纳米Tio:粒径分布和表面带电特性，并通过纳米Ti02 颗粒重新团聚实验来分析纳米颗粒在有机溶剂2一甲基毗咯烷酮困MP)中的分散。结 果表明，纳米Tio:表面沉淀 A1203为成膜包覆，并形成新的化学键，能提高纳米Ti仇 颗粒在NMP中的心电位和粒子重团聚性能DIS。纳米TIO:表面包覆钦酸丁脂偶联 剂和高分子聚乙烯毗咯烷酮后，颗粒表面屯电位绝对值降低，但其在NMP中的重团 聚性能提高，DIS值增大;纳米TIOZ表面吸附阴离子表面活性剂月桂酸钠后，颗粒 表面乙电位绝对值增加，在NMP中的重团聚性能提高，DIS值增大;十二烷基硫酸 钠、钦酸丁脂偶联剂和高分子PVP均能改善纳米TIO:颗粒在NMP中的重团聚性能 DIS。经过无机/有机复合表面修饰，纳米TIO:在NMP中的DIS值从包覆前的1 66min 提高到438min，分散性显著提高。用颗粒重团聚实验得到的DIS值能准确地反映纳 米颗粒的分散情况。5.采用耐高频脉冲电压实验研究纳米TIO:粒径、含量、无机表面修饰、有机表面修饰、 机械分散手段以及涂布条件对纳米Ti02爪Al复合材料耐变频性的影响，并用高阻计、 UV-VIS、热传导率仪等手段分析纳米TIO:颗粒和TIOZ/PAI复合材料的导电率、导 热率和紫外光吸收率等，以推测纳米Ti02/PAI复合电磁线耐变频机理。结果表明， 纳米TIO:形态结构、含量和在复合材料中的分散性对材料耐变频性有较大的影响， 纳米Tio:在电晕放电下能形成较致密的纳米TIO:无机保护层，快速传导热量和累计 的空间电荷，有效阻挡带电粒子和紫外光对内层有机绝缘材料的破坏，从而大幅度 提高电磁线绝缘材料在高频脉冲电压下的使用寿命。更多还原

【Abstract】 1. Based on the analysis to the premature failure processes of insulation material in the inverter-fed motor and the selective experiment for the modification additives of TiO2, SiO2, A12O3, ZnO, MgO, Fe2O3, ZrO2, BaTiO3, a design for the material with nano TiO2 modification was proposed. The morphologies of the nano particles were observed by XRD and TEM. The nano particles were dispersed into polyamideimide(PAI) evenly and thus inorganic/organic nanocomposite insulation materials were prepared. The high-frequency resistant properties of the relative nanocomposite insulation materials were investigated by the high-frequency resistant experiments. Experimental results indicated that the high-frequency resistant property of PAI could be improved by adding nanoTiO2, SiO2, A12O3, ZnO, MgO, ZrO2, BaTiO3. Among the particles, the nano rutile TiO2 was the best material to improve the high-frequency resistant property of PAI. The regular properties of the new electro-magnet wire prepared with nanocomposite TiO2/PAI insulation material were meet to the requests of Chinese National Standard GB/T6109.11-1990, which permitted the new electro-magnet wire to be used in reality. More important, for the rutile nano TiO2 prepared was a good dielectric material with good properties such as dielectric property, thermal conductivity, ultraviolet radiation absorbing ability and electric conductivity, the service life under high-frequency pulse voltage of the new composite electro-magnet wire could be raised to 7.45 times. After probation use in relative manufacturing enterprises, the new nanocomposite material obtained good appraise and showed good application prospect.2. Rutile TiO2 particles with different sizes were synthesized with TiCl4 and NaOH, and were prepared by controlling processing parameters. Experimental results indicated that as the concentration of NaOH was in range of 5.5 mol.L-1 to 13.75 mol.L-1, and the reactive temperature was higher than 82 , the stay time in reactor was longer than 2 hours, the nano rutile TiO2 could be obtained directly. The apparent activation energy of grain growth of nano TiO2 could be splitted into two sections at the point of 1023K, and the apparent growth activation energy was 0.3KJ.mol-1 as the calcining temperature was inrange of 873K to1023K, and it was elevated to 1.4 KJ.mol"1 as the calcining temperature was elevated. The crystal lattice aberration of nano TiO2 was decreased as the calcining temperature was increased and the calcining time was increased. The purity of the TiC>2 particles prepared was 99.7wt%, and the particle size was in the range of 25nm to 250nm, and the crystal structure was rutile.3. The nano TiO2 particles prepared were dispersed by sand milling and ultrasonic fragmentation, and the effects of relative processing parameters on the dispersing results were investigated with settlementation analysis, granularity analysis and re-agglomeration experiments. New mathematic models of sand milling and ultrasonic fragmentation were established with the Support Vector Machine Pattern Recognition, and the Pisch model was be modified. The new mathematic model indicated that with ultrasonic fragmentation, the re-agglomeration process of the nano TiO2 particles was shown three steps. With combination of sand milling and ultrasonic fragmentation dispersing method, dispersing effect of nano TiO2 was raised greatly. Initial average volume particle size of the nano TiO2 in water was dominated to below 150nm, DIS value of nano TiO2 in water was raised from 32min to 164min, and the diameter of nano TiO2 agglomeration in PAI was decreased from 30um to 50nm with the combination dispersing method.4. The surface of the nano TiO2 particles synthesized was treated with inorganic oxides and organic materials, and the morphologies and structures of the nano TiO2 particles were characterized by XPS, XRF and TGA. The size distribution and surface charges were measured with the electric potential analyzer and the laser granularity analyzer. The更多还原