The effect of low earth orbit atomic oxygen exposure on phenylphosphine oxide-containing poly(arylene ether)s

Abstract

Unoriented thin films of phenylphosphine oxide-containing poly(arylene ether)s were exposed to low Earth orbit aboard the space shuttle Atlantis (STS-51) as part of a flight experiment designated Limited Duration Candidate Exposure (LDCE 4–5). The samples were exposed to primarily atomic oxygen (!10,\7×1019 atoms/cm2). Based on post-flight analyses using atomic force microscopy, X-ray photoelectron spectroscopy, gel permeation chromatogrpahy and weight loss data, it was proposed that atomic oxygen exposure of these materials produces a phosphate layer at the surface of the samples, apparently by the reaction of atomic oxygen with the phosphorus in the polymer backbone. Ground-based oxygen plasma exposure experiments have previously shown that this phosphate layer provides a barrier against further attack by atomic oxygen [1]. The results obtained from these analyses compare favorably with those obtained from samples exposed to an oxygen plasma in ground-based exposure experiments [1]. © 1998 John Wiley & Sons, Ltd.