Study On The Aggregation Structure And Component Of The Polyimide/Alumina Nano-hybrid Films

As a high-performance engineering material, polyimide (PI) had excellent physical, chemical and electrical properties in a broad temperature range, and had a wide application area. SiO₂, Al₂O₃ and TiO₂ nano-particles with super good physical and chemical properties were introduced into the PI matrix, and the composite materials showed excellent combined property. Presently at home and overseas, the coherent articles on the affects about different doped methods to the aggregation structure, the relationship between the thermal performance and state gathered, and the accurate component analysis were very rare.In this paper, the polyamide acid (PAA) were prepared with the Pyromellitic dianhydride (PMDA), 4, 4′oxydianilline (ODA) in the solution of the N, N′-dimethylacetamide (DMAc) by the poly-condensation. The PAA were doped with the way of sol-gel and mixed with the nano-particles directly. At last the films which contained nano-particles (named as nano-particles film) and the Al sol (named as Al Sol film) individually were obtained by the imidization. The chemical structure, aggregation structure, thermal properties and inorganic component content of two films were characterized and analyzed by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and X-ray fluorescence spectrometer - dispersion wavelength (WDXRF), respectively.The results showed that, compared with nano-particles film, the nano-particles in the Al Sol film were smaller, and were dispersed very homogeneously from the aspect on aggregation structure. Increased with the content of Al₂O₃, the inorganic phase had evolved into network structure from the isolated spherical phase in the Al Sol film, but that of nano-particles film changed into the continuous distribution from the larger particle size. The thermal stability of two films had been improved with the addition of alumina from the aspect on thermal property. The thermal stability of the Al Sol film was better than that of nano-particles film. After the breakdown of DuPont membrane, the films had been damaged seriously on the edge of role. The organic matrix was completely decomposed and the inorganic particles were removed. However, the structure of inorganic phase embedded by organic leftovers had been changed a little near the breakdown hole. From the application of component analysis, the results with the method WDXRF was better than that with the way of electronic spectroscopy (EDX). The accuracy was higher and the deviation dispersed more narrowly. The results used with the method WDXRF about the content of heavy metal, the analysis of mineralization value, the improvement of preparation technology and treatment of the raw materials had great reference value.