基于相变材料微胶囊调控硅橡胶耐高低温交替冲击性能研究

Silicone rubbers possess a series of properties, which have been applied in high-tech fields of aerospace, ships, etc. The spacecrafts in the low orbit space face the harsh environment of high and low temperature alternative conversion and the harsh environment will accelerate aging and fatigue of silicone rubber adhesive sealing material for aerospace and affect the life and safety of spacecrafts. Phase change materials (PCMs) possess property of control temperature and if added microencapsulated phase change materials (MicroPCMs) into silicone rubbers, it will slow down the damage of silicone rubbers and the spacecrafts will safe operation..Based on the idea, we will study the resistance high and low temperature alternative shock with addition of MicroPCMs. We are going to select PCMs to prepare suitable MicroPCMs with silica shell as additive of silicone rubbers; The surface treatment agents were prepared and used them for MicroPCMs to realize the thermo-regulated and enhancement effect to silicone rubbers. The mechanical properties and thermal properties of silicone rubbers with MicroPCMs were studied. The resistance high and low temperature alternative shock of silicone rubbers with MicroPCMs was studied. The relationship between phase transition behavior of MicroPCMs and resistance high and low temperature alternative shock of silicone rubbers was built. These will provide a new method and theoretical basis to preparation of silicone rubbers with excellent resistance high and low temperature alternative shock used in space.

硅橡胶特殊的分子结构赋予其系列优异的特性，广泛应用在航空、航天、船舶等高技术领域。在低轨道空间运行的航天器面临高低温交变冲击的苛刻环境，加速了航天用硅橡胶粘接密封材料老化疲劳，影响航天器的寿命和安全。相变材料（PCMs）具有储热调温的性能，若在硅橡胶中加入相变材料微胶囊（MicroPCMs），有可能缓冲高低温交变对硅橡胶的破坏，保障航天器的安全运行。.基于此设想，本项目拟开展MicroPCMs调控硅橡胶耐高低温冲击性能研究。通过选择PCMs，制备符合硅橡胶添加的二氧化硅包覆MicroPCMs，制备合适的表面处理剂，对其进行表面处理，使其对硅橡胶起到相变调温和性能增强的双重效果；对添加MicroPCMs的硅橡胶综合性能进行评价，考察在高低温交替冲击下，MicroPCMs的相变行为与硅橡胶的性能变化之间的关系；为制备具有优异耐高低温交替冲击性能的空间用硅橡胶提供一种新方法和相应的理论基础。

硅橡胶特殊的分子结构赋予其系列优异的耐高低温性能，被广泛应用在航空、航天、船舶等高技术领域。本项目通过在硅橡胶中添加二氧化硅包覆正十八烷微胶囊制备具有良好调温性能的硅橡胶材料，进一步提高硅橡胶的耐高低温冲击性能。. 以正硅酸乙酯为硅源，正十八烷为相变材料，在酸性条件下，制备了具有密实结构外壳的单层二氧化硅包覆正十八烷微胶囊，当正十八烷/正硅酸乙酯为80/20时，微胶囊的熔融焓可高达175J/g；分别以正硅酸乙酯和全氢聚硅氮烷为硅源，成功制备了具有双层结构的n-Octadecane@MF/SiO2微胶囊，微胶囊表面二氧化硅层的沉积，能够大大提高微胶囊的耐温性能，从而提高了微胶囊的使用安全性。. 制备了不同苯基含量的硅橡胶并对其结构以及耐热性能进行探讨，研究发现，当苯基含量为10%时，硅橡胶的耐高低温性能最佳；基于DOPO，制备三种含有硅乙烯基和硅烷氧基的DOPO衍生物，利用硅烷氧基和微胶囊表面的硅羟基反应，有效地消除了微胶囊表面的羟基，提高了微胶囊和硅橡胶的相容性以及储存稳定性。. 制备了几种不同相变微胶囊含量的苯基硅橡胶材料，并对其热性能、力学性能以及耐高低温性能进行了研究，研究表明，相变微胶囊的加入，能够起到调节温度和补强的双重作用，当相变微胶囊的含量为25wt%时，硅橡胶材料的相变焓可达37 J/g，拉伸强度可达2.0MPa以上，但随着相变微胶囊含量的增大，硅橡胶的耐热性有明显的降低。初步考察了相变微胶囊含量为15%的苯基硅橡胶的耐高低温冲击的性能，在-100～80 ℃下，循环200次以后，硅橡胶对不锈钢仍具有良好的粘接性能。. 通过上述研究工作，为制备长时耐高低温冲击用的硅橡胶密封材料提供了新的思路和理论依据。