Effect of simulated low earth orbit radiation on polyimides (UV degradation study)

Abstract

UV degradation of polyimide films in air and vacuum were studied using UV‐visible, ESR, FTIR, and XPS spectroscopies. The UV‐visible spectra of polyimide films showed a blue shift in the absorption compared to Kapton. This behavior was attributed to the presence of bulky groups and kinks along the polymer chains which disrupt the formation of a charge‐transfer complex. The UV‐visible spectra showed also that UV irradiation of polyimides result extensively in surface degradation, leaving the bulk of the polymer intact. ESR spectra of polyimides irradiated in vacuum revealed the formation of stable carbon‐centered radicals which give a singlet ESR spectrum, while polyimides irradiated in air produced an asymmetric signal shifted to a lower magnetic field, with a higher g value and line width. This signal was attributed to oxygen‐centered radicals of peroxy and/or alkoxy type. The rate of radical formation in air was twofold higher than for vacuum irradiation and reached a plateau after a short time. This suggests a continuous depletion of radicals on the surface via an ablative degradation process. FTIR, XPS, and weight loss studies supported this postulate. An XPS study of the surface indicated a substantial increase in the surface oxidation after irradiation in air. The sharp increase in the CO binding energy peak relative to the CC peak was believed to be associated with an aromatic ring‐opening reaction. © 1995 John Wiley & Sons, Inc.

Sintering of Inkjet-Printed Silver Nanoparticles at Room Temperature Using Intense Pulsed Light

“…13 The UV light degrades polymer substrates; therefore, a UV filter was used to eliminate wavelengths under 380 nm. 14 The spectral distribution of the xenon flash lamp from 380 nm and 1000 nm for 50 J/cm 2 irradiation is shown in Fig. 4.…”

XPS study of the changes during the service life of polyester powder coatings

“…1 It has been used to study the degradation of polymers, 2,3 brought about by radiation in a vacuum, 4,5 photooxidation, 6 simulated low earth orbit environments, 7,8 degradation in solution 9,10 , ageing after plasma treatment 11 and in natural weathering situations. 12,13 The aim of this study was to determine if XPS is a useful technique for detecting the early stages of powder coating deterioration, specifically polyester coatings, which can lead to a lack of corrosion protection.…”

Selective Electroless Plating on UV-modified Polymer Film Surface Patterns to Form Copper Mesh as a Transparent Electrode

“…This result is suggested that chemical bond (C-C, C-O, C-H) cleavage reaction was occurred and modified on PET, PI and PEEK surfaces by UV exposure. [29][30][31] Therefore, the polar protic moieties of oxidized species are formed and achieved the selective electroless plating.…”