Preparation And Study Of Pi/Inorganic Nanoparticles Corona Resistance Hybeid Film

Aromatic polyimide(PI) exhibit outstanding electrical properties, mechanical properties and radiation resistance, especially at high temperature. It had been used abroad in the fields of the micro-electronics and navigates. In the recent years, with the rapid development of generator industry, high frequency generator and high voltage generator had appeared. In this case, the demand of insulation materials in the generator had reached a new level. Not only mechanical strength, modulus and thermal stability but also the corona-resistance capacity had been an very important factor. Though the corona-resistance capacity of a pure PI is good, it's not far enough for being used. Since the inorganic materials have better the corona-resistance than organic polymers, it is possible that the combinations of inorganic and organic components with a nanoscale domain size will improve the corona-resistance of organic polymers. Up to now, the study on the corona-resistance of polymer/nano-inorganic hybrid materials has seldom been reported in the literature. In this thesis, the organic-inorganic nanocomposites based on the polyimide as polymer matrix were prepared. The structure, morphology and properties of these nanocomposites were investigated, meantime, we will present the polymer structure- property relationship.In the this article, first we obtained the solution of polyamic acid (PAA) by the reaction of the Pyromellitic anhydride(PDMA) and bis (4-aminoph -enyl) ether(ODA) in the solvent N,N'-dimethylacetamide (DMAc). The nanoparticles are prone to aggregation because of the high surface energy. In order to resolve this problem, PAA were prepared though ultrasonic, and the inorganic nanoparticles the presence of three types: porous nanosilica a, spherical nanosilica and nano-alumina symmetrical redispersed in the solution PAA . Then PI/inorganic nanoparticles had been made in the some process. The Fourier transform infrared (FT-IR) analysis spectra showed the action. Atomic force microscope (AFM) of the hybrid films revealed that the inorganic phase of these hybrid films were redispersed in PAA and composed of original particles with average particle size of 30nm around. Time of corona-resistance of PI/ inorganic nanoparticles hybrid was longer than those of pure PI, and as the silica content increase, the time of corona-resistance PI/nano-SiO2 hybrid materials improved obviously through the experiment of the corona-resistance. In addition, we have research superficially the mechanism of the corona-resistance...