一种夹层定向氧化铝空心管气凝胶的制备及其压缩力学、热学性能研究

The alumina Aerogel is a kind of new light non-crystal solid-state material with nano porous framework structure composed of super-small nano-scale particles, which has excellent thermal-physical properties. However，it fragile framework and limited heat-insulating properties seriously limits its further applications. Therefore, in present project, a novel oriented alumina hollow-tube aerogel with interlayer structure is prepared, where the cellulose is used as template, with employing freeze-drying method combined with a low temperature casting method. Meanwhile, its mechanical and thermal properties are also studied. In detail, the cellulose/alumina aerogel is prepared, and then the cellulose template is deleted, so that obtaining target material. Based on above, the effects of content ratio of cellulose/alumina and pre-freezing rate on material structures, including interlayer instance and outer-diameter, wall-thickness and distribution density of alumina hollow-tube, are studied. The effect of material structures on compression mechanical properties and failure strength are studied. The effect of material structures on extreme temperature and thermal conductivity. This study can provide new idea for structural design and experimental evidence for quantifying.mechanical and thermal properties of this aerogel, and lay foundations for its engineering applications.

氧化铝气凝胶是一种纳米颗粒聚集而成的新型轻质纳米多孔非晶固态材料，具有优异的热物理性能。但其脆弱的骨架结构以及有限的力学性能极大地限制了其实际应用。因此，本项目以纤维素为模板，采用冷冻干燥法结合低温铸造工艺制备一种新颖的夹层定向氧化铝空心管气凝胶，获得一种微结构各向异性的气凝胶材料，保持其隔热性能的同时增强气凝胶材料的力学性能，并且对其压缩力学、热学性能进行深入系统地研究。具体地，制备纤维素/氧化铝复合气凝胶，然后去掉纤维素模板进而获得所需气凝胶材料，研究纤维素/氧化铝含量比例以及凝胶预冻速率对材料结构(夹层间距以及氧化铝空心管外径、壁厚以及分布密度)的影响，揭示材料结构对其力学行为以及压缩失效强度的影响规律，研究材料结构对其最高使用温度以及热导率的影响规律。通过本项目研究，为制备氧化铝气凝胶提供新的结构设计思路，为量化这一类气凝胶材料的压缩力学、热学性能提供实验依据，为工程应用奠定基础。

本项目研究了各向异性树脂基复合材料的界面增强机理，设计并制备了可以360°感知方向的人工智能皮肤；为深入探讨复合材料界面增强机理，通过先进原位力学测试技术探究了微纳米尺度下材料的力学性质，通过制备一种电极材料SnO2纳米线，采用先进的微纳米操作技术结合微纳米测量器件，获得了SnO2纳米线充放电过程中锂化还原循环的力学性质变化规律，首次获得了电极材料锂化还原过程对力学行为的影响机制。以螺丝钉为设计灵感，通过化学打开的方法制备了一种半打开型的碳纳米管材料，增加了碳纳米管与基体材料的结合面积，增强了界面结合，通过控制碳纳米管打开程度获得了一种树脂基复合材料，并通过理论计算验证了其增强原理。采用分子动力学模拟方法建立了两个碳纳米管螺旋纤维丝结构，揭示了碳纳米管纤维内部碳管互相作用的本质，在此基础上，考察了连续碳纳米管纤维拉伸力学性质，揭示了螺旋角以及碳纳米管形变对碳纳米管纤维力学性质的影响规律，实现了碳纳米管纤维从聚合物基体中拔出模拟。