| 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... |
PDF Full Text Request