Aging of Polyimides in High Temperature Environments

Abstract

Summary: Membranes made of high permeable fluorinated aromatic polyimide synthesized from 6FDA (4,4'-hexafluoroisopropylidene diphthalic anhydride) and 4MPD (2,3,5,6-tetramethyl-1,4-phenylene diamine) have been thermally treated to examine their aging behaviour at high temperature. The aging process was investigated by means of gas permeation tests, IR spectroscopy and thermogravimetric analysis combined with mass spectral analysis of the gaseous decomposition products. Up to around 400 8C thin films of the material show no major degradation but changes in color, flexibility and separation characteristics for O 2 /N 2 were observed.

Thermal stability of 6FDA-(co-)polyimides containing carboxylic acid groups

“…Earlier work on aging of polyimides with focus on 6FDA-4MPD was done in our group [8] and will be compared to the carboxylic acid group containing derivative 6FDA-4MPD:6FDA-DABA 4:1 investigated in this work. Acid group bearing copolyimides are even more interesting materials than the former discussed ones as their carboxylic acid groups can be used to perform polymer analogous reactions e.g.…”

Solubility of Gases and Free Volume Evolution in R-BAPB Polyimide: Molecular Dynamics Simulations and Analytical Theory Insights into Cooling Velocity Effect

“…Indeed, the experimental data show that the properties of polymeric membranes are largely determined by the protocol for their preparation. − Particularly, a well-known example is gas sorption and its dependence on the polymer thermal treatment ,, or aging. , In both types of experiments, gas solubility was found to be lower for samples that had been cooled slower or aged longer. Such solubility dependence is typically explained by the decrease of the polymer excess free volume. − …”