低地轨道环境中聚酰亚胺和硅橡胶原子氧防护技术研究
发布时间：2018-11-16 09:50
【摘要】：低地球轨道环境中的原子氧(AO)具有强氧化性,其高能碰撞会导致聚合物材料性能退化,严重影响航天器的正常工作。本文借助溶胶-凝胶(Sol-gel)法和湿化学改性法在聚酰亚胺薄膜(Kapton)和硅橡胶(SR)表面制备无机氧化物涂层,通过AO模拟试验评价其防护效果。同时研究了聚合物基体表面改性的微观变化、涂层与基体的界面结合状态等问题。主要研究工作如下:1.SiO_2溶胶体系研究:为制备适宜镀膜的溶胶体系,本文研究了乙醇用量、酸碱催化剂、陈化温度等条件对SiO_2溶胶体系的稳定性和粒径的影响。结果表明:溶胶浓度较小时,粒径普遍较小,溶胶的凝胶时间延长。此外酸催化的溶胶体系粒径普遍较大,溶胶的稳定性也较差,接近凝胶时粒径急剧增大。而相同实验条件下,碱催化的SiO_2溶胶体系粒径较小,稳定性较高。陈化温度也对溶胶稳定性产生较大的影响,随着温度的升高,酸催化溶胶的稳定性降低。2.碱液刻蚀与硅烷偶联剂相结合的表面改性方法研究:用低浓度碱液刻蚀去除Kapton基材的表面钝化层,再用硅烷偶联剂进行改性。改性后的Kapton基材表面亲水性显著增加,SnO_2/SiO_2溶胶很容易在其表面铺展形成均匀的液膜。采用这种方法制得的涂层与基材之间粘附牢固。AO辐照试验后,涂层依然均匀致密,具有很好的抗AO能力,AO的侵蚀效应仅相当于原始Kapton的4.1%,且赋予样品良好的抗静电能力。3.柔性SR表面涂层易开裂问题研究:本文对SR基体和表面改性过程进行了研究。研究发现:硅烷偶联剂KH-550改性后的SR样品表面已产生不规则裂纹。SR基体与改性层之间的应力是导致裂纹的主要原因,弯曲变形等外力加剧应力累积,造成更多裂纹。采用有机溶剂适度溶胀SR,可有效缓解SR基体与表面改性层之间的应力,从而大幅减少了改性过程以及镀膜过程所产生的裂纹。4.SiO_2掺杂对提高柔性SR抗AO性能研究:研究表明,适宜浓度的SiO_2溶胶加入SR基胶中,能够实现SiO_2在SR中均匀分散。AO辐照试验后,掺杂SiO_2溶胶的样品相比于原始SR,表面依然平整致密,裂纹较少,AO侵蚀危害有所缓解。同时SR的机械性能得到提高。
[Abstract]:Atomic oxygen (AO) in low Earth orbit environment has strong oxidization and its high energy collision will degrade the properties of polymer materials and seriously affect the normal operation of spacecraft. Inorganic oxide coatings were prepared on the surface of polyimide film (Kapton) and silicone rubber (SR) by sol-gel (Sol-gel) method and wet chemical modification method. The protective effect was evaluated by AO simulation test. At the same time, the microcosmic change of polymer matrix surface modification and the interfacial bonding state between coating and substrate were studied. The main research work is as follows: the study of 1.SiO_2 sol system: in order to prepare the suitable sol system, the effects of the amount of ethanol, acid base catalyst and aging temperature on the stability and particle size of SiO_2 sol system were studied in this paper. The results show that the particle size is generally smaller and the gel time is prolonged when the concentration of sol is small. In addition, the particle size of the acid-catalyzed sol system is generally larger, and the stability of the sol is also poor. The particle size increases sharply when the gel is close to the gel. Under the same experimental conditions, the SiO_2 sol system catalyzed by alkali has smaller particle size and higher stability. Aging temperature also had a great effect on the stability of the sol. With the increase of the temperature, the stability of the acid catalyzed sol decreased. 2. Study on the Surface Modification method of Alkali etching combined with Silane Coupling Agent: the surface passivation layer of Kapton substrate was etched with low concentration alkali solution and then modified with silane coupling agent. The surface hydrophilicity of the modified Kapton substrate was significantly increased, and the SnO_2/SiO_2 sol could easily spread on the surface to form a uniform liquid film. The coating prepared by this method adheres firmly to the substrate. After AO irradiation, the coating is still uniform and compact, and has good ability to resist AO. The corrosion effect of AO is only 4.1 of that of the original Kapton. And gives the sample good antistatic ability. 3. Study on the easy cracking of flexible SR Surface coating: the SR substrate and surface modification process were studied in this paper. It is found that the surface of SR samples modified by silane coupling agent KH-550 has produced irregular cracks. The stress between the SR matrix and the modified layer is the main cause of the cracks. The external forces such as bending deformation aggravate the accumulation of stress and cause more cracks. The stress between the SR matrix and the surface modified layer can be effectively alleviated by moderate swelling of SR, in organic solvent. Thus, the cracks produced by the modification process and the coating process were greatly reduced. The study on the improvement of AO resistance of flexible SR by 4.SiO_2 doping showed that the appropriate concentration of SiO_2 sol was added to SR base adhesive. After AO irradiation, the samples doped with SiO_2 sol were still flat and compact compared with the original SR, surface, the cracks were less, and the corrosion damage of AO was alleviated. At the same time, the mechanical properties of SR are improved.
【学位授予单位】：烟台大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB306
本文编号：2335182
[Abstract]:Atomic oxygen (AO) in low Earth orbit environment has strong oxidization and its high energy collision will degrade the properties of polymer materials and seriously affect the normal operation of spacecraft. Inorganic oxide coatings were prepared on the surface of polyimide film (Kapton) and silicone rubber (SR) by sol-gel (Sol-gel) method and wet chemical modification method. The protective effect was evaluated by AO simulation test. At the same time, the microcosmic change of polymer matrix surface modification and the interfacial bonding state between coating and substrate were studied. The main research work is as follows: the study of 1.SiO_2 sol system: in order to prepare the suitable sol system, the effects of the amount of ethanol, acid base catalyst and aging temperature on the stability and particle size of SiO_2 sol system were studied in this paper. The results show that the particle size is generally smaller and the gel time is prolonged when the concentration of sol is small. In addition, the particle size of the acid-catalyzed sol system is generally larger, and the stability of the sol is also poor. The particle size increases sharply when the gel is close to the gel. Under the same experimental conditions, the SiO_2 sol system catalyzed by alkali has smaller particle size and higher stability. Aging temperature also had a great effect on the stability of the sol. With the increase of the temperature, the stability of the acid catalyzed sol decreased. 2. Study on the Surface Modification method of Alkali etching combined with Silane Coupling Agent: the surface passivation layer of Kapton substrate was etched with low concentration alkali solution and then modified with silane coupling agent. The surface hydrophilicity of the modified Kapton substrate was significantly increased, and the SnO_2/SiO_2 sol could easily spread on the surface to form a uniform liquid film. The coating prepared by this method adheres firmly to the substrate. After AO irradiation, the coating is still uniform and compact, and has good ability to resist AO. The corrosion effect of AO is only 4.1 of that of the original Kapton. And gives the sample good antistatic ability. 3. Study on the easy cracking of flexible SR Surface coating: the SR substrate and surface modification process were studied in this paper. It is found that the surface of SR samples modified by silane coupling agent KH-550 has produced irregular cracks. The stress between the SR matrix and the modified layer is the main cause of the cracks. The external forces such as bending deformation aggravate the accumulation of stress and cause more cracks. The stress between the SR matrix and the surface modified layer can be effectively alleviated by moderate swelling of SR, in organic solvent. Thus, the cracks produced by the modification process and the coating process were greatly reduced. The study on the improvement of AO resistance of flexible SR by 4.SiO_2 doping showed that the appropriate concentration of SiO_2 sol was added to SR base adhesive. After AO irradiation, the samples doped with SiO_2 sol were still flat and compact compared with the original SR, surface, the cracks were less, and the corrosion damage of AO was alleviated. At the same time, the mechanical properties of SR are improved.
【学位授予单位】：烟台大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB306
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