Study On Structure And Properties Of Nano Organic Aluminous Hydrolysate Hybrid Polyimide Film

With the rapid development of science and technology, it presents higher requirements on the performance of engineering dielectric materials. Inorganic-hybrid polymer materials have attracted much attention for their special properties. Because of their excellent electric properties especially on the corona resistance, Kapton 100CR film materials have been applied in the fields of electronic equipment, electrical engineering, etc.In this paper, hybrid polyimide film of organic aluminous hydrolysate and composite polyimide film were prepared through sol-gel reaction. Their electric properties, surface morphology and structure were measured and analyzed by corona discharge measuring equipment, breakdown strength measuring system, and dielectric spectrometer, SEM and UV-VIS spectrum, respectively.It is shown that the corona-resistant lifespan of composite PI film with 24wt% amount of organic aluminous hydrolysate (content as Al₂O₃) is 35.6 hours, about 10 times longer than that of pure PI film, and it is similar to that of DuPont 100CR film, but hybrid film's corona resistance property is inferior to DuPont 100CR film's. It is revealed that the breakdown strength of hybrid film is lower than that of pure film, while composite film's breakdown strength is greatly higher than that of hybrid film, though DuPont film's breakdown voltage is higher than that of both, but lower than that of pure film by 10%.The relative dielectric constant of hybrid film is higher than pure film in low frequency region and intermediate region, which declines quickly in high frequency region,but it increases as increasing of the inorganic content in the hybrid films in low frequency region. The dielectric loss tanδof hybrid film descend gradually in low frequency region, which are higher than that of pure PI film. While the dielectric loss tanδof hybrid film rises firstly and declines widely with frequency in intermediate and high frequency region, but all the three films'tanδare larger than pure film's. The curves of weight loss with temperature show that the decomposing temperatures of the hybrid films are not obviously higher than that of pure film. The UV-VIS spectrum reveals that the T% of composite films is smaller than that of pure film, but the transparence of the composite films are also good. It is illustrated by SEM that the inorganic particles are not distributed homogeneously on the surface of hybrid film, and with the rising of the inorganic content, the inorganic nano-particles reunite seriously on the surface of hybrid film. Compared with the surface of DuPont 100CR, the inorganic nano-particles do not disperse homogeneously in hybrid films.