Atomic Oxygen-Resistant Epoxy-amines Containing Phenylphosphine Oxide as Low Earth Orbit Stable Polymers
Atomic Oxygen-Resistant Epoxy-amines Containing Phenylphosphine Oxide as Low Earth Orbit Stable Polymers
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DOI：
10.1021/acsapm.0c01017
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发表时间：
2021-01-08
影响因子：
5
通讯作者：
Wiggins, Jeffrey
中科院分区：
文献类型：
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作者：
Fuchs, Witold K.;Sarantes, Catherine;Wiggins, Jeffrey
原子氧（AO）会攻击近地轨道航天器表面的碳纤维增强聚合物，威胁航天器的安全运行和使用寿命。将苯基氧化膦 (PPO) 基团纳入聚合物链中提供了一种自我再生的 AO 防护方法，但人们对此仍知之甚少。在此，合成了含有 PPO 基团的环氧树脂，其中磷 [P] 的浓度从 0 wt% 增加到 8 wt%，以研究其 AO 抗性。通过氧等离子体蚀刻将含 PPO 的环氧树脂薄膜暴露于 AO，并通过干涉测量、X 射线光电子能谱和原子力显微镜-红外光谱进行表征。测量证实，这些材料暴露于 AO 中会在样品表面产生钝化磷酸盐 (POx) 层，从而使 AO 侵蚀率降低高达 100 倍。此外，还获得了对初始 [P]、钝化层表面拓扑和聚合物深度剖面之间关系的重要见解。至关重要的是，结果表明，与大多数有机聚合物相比，这些材料在暴露于 AO 时有利地不表现出线性侵蚀速率，并且它们的 AO 抗性可以通过合成掺入具有不同 [P] 的单体来轻松调节。
Atomic oxygen (AO) attacks carbon-fiber reinforcing polymers on the surfaces of spacecraft in low Earth orbit and threatens safe spacecraft operation and service life. Incorporating phenylphosphine oxide (PPO) groups into polymer chains offers a self-regenerating method of protection from AO but remains poorly understood. Herein, epoxies containing PPO groups were synthesized with increasing concentrations of phosphorus [P] from 0 to 8 wt % to investigate their AO resistance. Thin films of PPO-containing epoxies were exposed to AO via oxygen plasma etching and characterized by interferometry, X-ray photoelectron spectroscopy, and atomic force microscopy-infrared spectroscopy. Measurements confirmed that the exposure of these materials to AO produces a passivation phosphate (POx) layer on the surface of the sample, resulting in up to 100X decrease in AO erosion rates. Furthermore, key insights into the relationship between initial [P], passivation layer surface topology, and polymer depth profiles were obtained. Crucially, the results indicate that these materials advantageously did not exhibit linear erosion rates when exposed to AO, in contrast to most organic polymers, and their AO resistance can be readily tuned via synthetic incorporation of monomers with varying [P].