Degradation of polymers by hyperthermal atomic oxygen

Abstract

Degradation of polymers by hyperthermal species (e.g. atomic oxygen (ATOX)) occurs in a variety of practical systems including external surfaces of spacecraft in low earth orbits (LEO), for which the impact with the residual atomic oxygen (impact energy 3-7 eV) results in significant erosion. In the present work the effects of hyperthermal species on two polymers commonly used for space applications (Kapton H and Teflon FEP) were investigated. The polymers were exposed to 30 eV 0' and Ne+ fluences of 10'5-10'9 ionscm-2. The phenomena investigated included total mass loss and changes of surface morphology (SEM and AFM) and surface chemical composition (XPS). The relative significance of the collisional and chemical degradation processes was evaluated by comparing the effects of 0' and Ne' bombardment. AFM analysis was found very powerful in studying the damage from its initial atomic scale (roughness of -1 nm) to its final macroscopic scale (roughness > 1 am).

3D Graphene-Infused Polyimide with Enhanced Electrothermal Performance for Long-Term Flexible Space Applications

“…For the space simulation studies, 3D‐C/PI was exposed to gamma ray and AO at different doses, as well as outgassing tests according to European standards . The changes in electrical behavior have been monitored and the structural changes of the material before and after the exposures have been studied with SEM . The durability of these PI‐based composites is not expected to be affected by solar vacuum ultraviolet (VUV) radiation, as the similar polyimide, Kapton, has been shown to be insensitive to VUV radiation …”

The effect of the addition of talc on tribological properties of aramid fiber‐reinforced polyimide composites under high vacuum, ultraviolet or atomic oxygen environment

“…The erosive potential of AO is substantially increased as a result of the high orbiting speed of spacecraft of 7–8 km/s. In this relative velocity, the AO flux is about 10 12 –10 15 atoms/(cm 2 •s) and kinetic energy is about 5 eV . Hyperthermal AO reacts with polymers and any other carbon‐based materials and causes mass loss and changes in surface morphology.…”

Ultraviolet or atomic irradiation effect on the polyimide composite lubricating coating

“…An in-depth study on the erosion process of PI materials when exposed to an AO environment is important in predicting performance characteristics such as in-space durability. The detailed erosion mechanisms of PI materials in AO conditions are still poorly understood because of the limitation of AO simulation technology and the complexity of mechanisms [21][22][23]. Duo et al [22] studied the erosion behavior of Kapton (PI composite film made by DuPont, Wilmington, Delaware, USA) exposed to AO conditions in a ground-based simulation facility and the results indicated that Kapton reacted with AO to generate CO 2 , resulting in mass loss.…”