Transparent polyimides

Angeltr—>has briefly reported in a patent the addition of metal ions to several types of polyimides. The object of the invention was a process for forming particle-containing (shaped structures. Unlike the work discussed previously, all of the metals were added in the form of coordination complexes rather than as simple anhydrous or hydrated salts. The properties of only one film (e.g. cast from a N,N-dimethylformamide(DMF) solution of 4,4 -diaminodiphenyl methane, pyromellitic dianhydride and bis(acetylacetonato)-... 

I, H. Tseng, Y. F. Liao, J. C. Chiang, M. H. Tsai, Transparent polyimide/graphene oxide nanocomposite with improved moisture barrier property., Materials Chemistry and Physics, vol. 136, pp. 247-253, 2012. 

Aspects of the Radiation Chemistry of Some Transparent Polyimides... 

So, the polymers used in space, and particularly those used on the outer surfaces of space vehicles, must be able to withstand extremely harsh environments. Therefore, before any polymer is used in a space, it is important to assess its sensitivity to space conditions. We have previously reported on the sensitivity of several transparent polyimides to conditions that are similar to those found in GEO and LEO In this paper some of the results of these... 

The G-values for radical formation on vacuum radiolysis of some polyimides at 77 K are given in Table I. These radical yields provide an assessment of the relative radiation sensitivities of the polyimides. The results show that Kapton is the most radiation resistant (lowest G-value) of the polyimides, but that the stabilities of the other transparent polyimides are also... 

Devasahayam et al. (72) have also carried out Raman studies of the changes in the functional group concentrations at high dose for several other transparent polyimides. In this study the polyimides were irradiated in an inert atmosphere by e-beam over a range of temperatures from ambient temperature to 503 K. The Raman study indicated that the principal centres for radiation damage in these polyimides were located at the phenyl ether units in the diamine components and at the fluorinated isopropylidine units in the dianhydride components. 

The preparation of composites prepared by high temperature decomposition reactions have mainly concentrated on polyimides and reactive inorganic additives (e.g., simple salts and complexes). In many cases polymer-metal composites have been unintentionally produced by workers whose primary goal was the modification of polyimide properties by incorporation of metal ions. For example, approximately 30 years ago Angelo briefly reported in a patent the addition of metal ions to several types of polyimides for the purpose of forming particle-containing transparent polyimide shaped structures. Ten years... 

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