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首页> 外文期刊>ACS applied materials & interfaces >Resistance of POSS Polyimide Blends to Hyperthermal Atomic Oxygen Attack
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Resistance of POSS Polyimide Blends to Hyperthermal Atomic Oxygen Attack

机译:POSS聚酰亚胺共混物对高温原子氧攻击的抵抗力

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摘要

Copolymers of polyhedral oligomeric silsesquioxane (POSS) and polyimide (PI) have shown remarkable resistance to atomic oxygen (AO) attack and have been proposed as replacements for Kapton on the external surfaces of spacecraft in the harsh oxidizing environment of low Earth orbit (LEO). POSS PI blends would be an economical alternative to the copolymers if they also resisted AO attack. Thus, blends of trisilanolphenyl (TSP) POSS and PI with different weight percentages of the Si7O9 POSS cage were cast into films and exposed to a hyperthermal AO beam, and they were characterized in terms of their recession, mass loss, surface morphology, and surface chemistry. In order to compare the AO resistance of the blends with POSS PI copolymers, samples of previously studied copolymers were also investigated in parallel with the blends. For all POSS PI materials, the AO resistance increased with increasing AO fluence and with increasing POSS cage loading. At similar POSS cage loadings and exposure conditions, the TSP POSS PI blends showed comparable erosion yields to the POSS PI copolymers, with specific samples of blends and copolymers achieving erosion yields as low as 0.066 X 10(-24) cm(3) atom(-1) with an AO fluence of 5.93 X 10(20) O atoms cm(-2). SEM and XPS analyses indicated that passivating SiOx layers were formed on the surfaces of all POSS-containing polymers during AO exposure. Thus, a TSP POSS PI blend is proposed as a low-cost variant of a POSS polyimide for use in extreme oxidizing environments, such as LEO.
机译:多面体低聚倍半硅氧烷(POSS)和聚酰亚胺(PI)的共聚物具有出色的抗原子氧(AO)攻击的能力,并已提出在低地球轨道(LEO)的苛刻氧化环境中替代航天器外表面上的Kapton。 。如果POSS PI共混物还可以抵抗AO攻击,那么它将是共聚物的经济替代品。因此,将具有不同重量百分比的Si7O9 POSS笼的三硅烷醇苯基(TSP)POSS和PI的共混物浇铸成膜并暴露于高温AO光束中,并根据其退缩,质量损失,表面形态和表面进行表征化学。为了比较共混物与POSS PI共聚物的抗AO性能,还与共混物平行研究了先前研究的共聚物样品。对于所有POSS PI材料,AO阻力随着AO流量的增加和POSS笼式载荷的增加而增加。在类似的POSS保持架载荷和暴露条件下,TSP POSS PI共混物显示出与POSS PI共聚物相当的侵蚀率,共混物和共聚物的特定样品实现了低至0.066 X 10(-24)cm(3)原子的侵蚀率( -1)的AO通量为5.93 X 10(20)O原子cm(-2)。 SEM和XPS分析表明,在AO暴露过程中,所有含POSS的聚合物表面均形成了钝化SiOx层。因此,提出了一种TSP POSS PI共混物,作为POSS聚酰亚胺的一种低成本变体,可用于极端氧化环境(如LEO)中。

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