Temperature dependence of the properties of vapor-deposited polyimide

Abstract

The Young's modulus and helium gas permeability of vapor-deposited poly͑4,4Ј-oxydiphenylenepyromellitimide͒ were measured at cryogenic and elevated temperatures ͑10-573 K͒. The Young's modulus decreased with increasing temperature from 5.5 GPa at 10 K to 1.8 GPa at 573 K. The temperature dependency of the permeability followed the Arrhenius' relationship, with different activation energy for permeation for samples imidized under different conditions. The effect of the imidization conditions on the permeation properties could be explained in terms of morphology/crystallinity as determined by x-ray diffraction techniques. Imidizing in air instead of nitrogen increased the permeability while lowering the activation energy for permeation and crystallinity. Imidizing at higher heating rates ͑in nitrogen͒ resulted in higher permeability, lower activation energy for permeation, and larger and fewer crystallites with better-aligned lattice planes.

Temperature dependence of the leak rate and permeability of helium gas through Kapton foils

“…The result for the activation energy E P mentioned in [20] is not compatible with our result, but off by about 20%. No numerical value for the obtained permeability constant is given in that reference, however, reading off their Fig.…”

“…And finally in Table 1 Literature values for the permeability constant P and the activation energy E P . Unless otherwise stated, the permeability constants are indicated at T ¼296 K, and were converted by us to units of barrer using the conversion factors given in Table 2 of [13] [19] Activation energy (kJ/mol) Source 18:2 7 0:3 g [20] a Official Datasheet by DuPont. Indicate "permeance" which is P=d.…”

Properties and structure of vapor-deposited polyimide upon electron-beam irradiation

“…1,2 Previous efforts have made possible the fabrication of aromatic polyimide capsules from pyromellitic dianhydride ͑PMDA͒ and 4 , 4Ј-oxydianiline ͑ODA͒ by employing a technique based upon vapor-phase polymerization, [3][4][5] or by an emulsion technique, 6 and the properties of the capsules critical to the ICF application were assessed. [7][8][9][10] It was verified that the PMDA-ODA polyimide capsules, prepared via the vapor-deposition technique, possessed comparable yet distinct properties from the commercial PMDA-ODA polyimide ͑Kapton͒, produced by solutionbased methods. Prior works have yet to examine one attribute of the capsules vital to the ICF application: their resistance to ␤ radiation emitted by tritium, a main component of the fuel mixture currently used in ICF.…”

Carrier Mobility in Organic Thin-film Transistors: Limiting Factors and Countermeasures

“…In this work, we adopt K S =0.95 which is in the middle of the range used for organic crystals, 0.87-1.05 [40][41][42][43]. Figure 12(a) shows the W-H plots of major diffraction peaks obtained with pentacene thin films [6].…”