Photosensitive Polyimide Synthesis And Characterization,

Polyimide (PI) is a kind of high-performance polymer with high thermal stability, excellent electrical insulation, inert chemical properties and good machining characteristics. It has been extensively applied in the domain of modern advanced technique, such as microelectronics, photoelectricity and optic materials. Photosensitive polyimides (PSPI) that possess both heat-resistant and sensitive properties have been attached importance to chemistry, materials and optics and related subjects .Now they have been becoming current the research heat of organic functional materials and getting quick development.On the basis of reference to the research in PIs, this article overviews the development of PSPIs in domestic and overseas studies and sums up synthetic methods of them. A notion of preparation a novel PSPI by the means of synthesis for photosensitive diamines and then polymerization to get the PSPI on which has the main chain of photosensitive functional groups has been also put forward.According to the principles of photochemistry and through the molecular design for organic functional materials, the author succeeds in designing novel photosensitive diamines with the structure of cinnamoyl group. Setting out from the angle of organic synthesis, the method for synthesizing this kind of photosensitive diamines has been also investigated. Adopting successfully the technology of the Aldol Condensation and protection for amino group which makes ketone reacted with aldehyde and then hydrolyzed by hydrochloric acid, we get the target products: Diamine A and Diamine B. The total yield rate attains 61.9%, 50.4% and the maximal absorption wavelength of UV spectrum is 349nm, 361nm respectively. The relationship between structure and performance is also analyzed.Diamine A: 1- (3-aminophenyl)-3-(4-aminophenyl)-2-Propen-1-oneDiamine B: 1-(3-aminophenyl)-3-{4-(3-(3-aminophenyl)-3-oxo-1-propenyl) phenyl}-2-Propen-1-oneThe maximal absorption wavelength of UV spectrum and weight-average molar mass of PAA that is prepared by the means of solution polymerization is 365nm and 3319 respectively. PSPI is thus got after heat treatment of PAA. The heat behavior of PSPI is studied by the analysis of TGA curve and its heat-resistant temperature is over 400℃. All these have successfully solved following problems such as heat-resistant property, loss of film, the matching of wave band for sensitivity, purity and stability of the PSPI product. The designed synthetic method has many merits: simple process, the equipments request is quite low, plentiful raw material source and products easy to separate purely which benefit for applications.At the same time, the key technique for synthesis of PSPI is discussed and affection laws on reactions are also analyzed, referred by weight-average molar mass. The preferable process and conditions are got. Reasonable explanations on the phenomenon of gel are brought forward.The structure characteristic and performance testing show that the structures of the synthetic compounds are absolutely consistent with the designed ones and sensitive properties are quite good enough.