基于纳米修饰的烯酸树脂矩阵材料的热保护系统的氧-布坦废弃测试
George Pelin1, Cristina Elisabeta Pelin1, Adriana Stefan1
1INCAS-National Institute for Aerospace Research "Elie Carafoli", B-dul Iuliu Maniu 220, 061126 Bucharest, Romania.
Polymers
|October 14, 2023
概括
碳感热保护系统 (TPS) 的性能优于软木制的系统. 添加碳化纳米粒子进一步提高了TPS性能,减少了极端热测试期间的温度增加和质量损失.
科学领域:
- 材料科学 材料科学 材料科学
- 航空航天工程 航空航天工程
背景情况:
- 开发先进的热保护系统 (TPS) 对太空应用至关重要.
- 目前的TPS通常使用结合强化结构的废弃材料.
研究的目的:
- 开发和评估两种类型的TPS,具有不同的削减强化 (软木与碳).
- 为了研究碳化纳米粒子 (nSiC) 添加对TPS性能的影响.
- 评估在极端条件下开发的TPS的热和形态结构行为.
主要方法:
- 使用树脂制造的TPS与CFRP和废弃层 (软木或碳) 的制造.
- 用不同重量百分比的nSiC (1%和2%) 浸加强材料.
- 热导电性测试和氧-butan火焰测试,以模拟空间的热条件.
- 使用光学和扫描电子显微镜测试后进行形态结构性表征.
主要成果:
- 基于碳的TPS表现优于基于软木的TPS,在测试后显示较低的温度增加率,减少的质量损失和更好的形态结构完整性.
- 与未填充的样本相比,nSiC在软木和碳TPS中的加入显著提高了耐热性和材料稳定性.
- nSiC的添加对温度上升,质量损失和侵蚀材料的微观结构产生了积极的影响.
结论:
- 与软木基材料相比,碳增强的废弃材料提供了增强的热保护能力.
- 碳化纳米颗粒是有效的添加剂,可以提高基于树脂的TPS的热性能和耐久性.
- 开发的TPS,特别是碳和nSiC增强的变种,显示出对要求高的太空应用的前景.
相关概念视频
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.