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无机材料学报

• 研究论文 •    

SiO2纤维气凝胶的压缩回弹机理

李福平1,2, 褚家宝1,2, 仇海波1,2, 党薇1,2, 李晨曦1,2, 赵康1,2, 汤玉斐1,2   

  1. 1.西安理工大学 材料科学与工程学院, 西安 710048;
    2.陕西省腐蚀与防护重点实验室, 西安 710048
  • 收稿日期:2025-01-25 修回日期:2025-03-18
  • 作者简介:李福平(1985-), 男, 副教授. E-mail: lifp@xaut.edu.cn
  • 基金资助:
    国家自然科学基金(53404411,52172074,51904242);陕西省教育厅专项计划计划(23JC056)

Compressive Resilience Mechanism of SiO2 Nanofibre Aerogels

LI Fuping1,2, CHU Jiabao1,2, QIU Haibo1,2, DANG Wei1,2, LI Chenxi1,2, ZHAO Kang1,2, TANG Yufei1,2   

  1. 1. College of Materials Science and Technology, Xi'an University of Technology, Xi’an 710048, China;
    2. Shaaxi Province Key Laboratory of Corrosion and Protection, Xi'an University of Technology, Xi’an 710048, China;
  • Received:2025-01-25 Revised:2025-03-18
  • About author:LI Fuping (1985-), Associate Professor. E-mail: lifp@xaut.edu.cn
  • Supported by:
    National Natural Science Foundation of China (53404411, 52172074, 51904242); Scientific Research Program Funded by Shaanxi Provincial Education Department (23JC056)

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摘要： SiO2气凝胶具有低密度、极低热导率和良好的化学稳定性等特点,在航空航天、建筑节能和能源化工等领域具有广阔应用前景。然而,传统SiO2颗粒气凝胶因相邻颗粒间形成珍珠项链状结构,导致其脆性大且回弹性差。通过以纳米纤维为结构单元制备SiO2纤维气凝胶,能够有效克服传统颗粒气凝胶的脆性,提升压缩回弹性,但其压缩回弹机理尚不明确。本研究通过静电纺丝制备柔性SiO2纳米纤维,分析了煅烧温度对纤维相结构及柔性的影响,揭示了纤维的柔性机理。在此基础上,采用冷冻干燥法以柔性纤维为结构单元制备了SiO2纤维气凝胶,探究了固含量对孔结构、强度和回弹性能的影响规律,基于有效纤维长度的屈曲变形理论揭示了压缩回弹机理。结果表明,煅烧温度影响SiO2纳米纤维的非晶结构和柔性,随着煅烧温度升高,SiO2的短程有序度增加,导致纤维柔性变差。SiO2纤维气凝胶的压缩回弹性与固含量密切相关。0.5%固体含量(质量分数)的气凝胶表现出较好的压缩回弹性,能量损失系数为0.6,压缩回弹率为55.2%。气凝胶的压缩回弹性取决于有效纤维长度和纤维最小曲率半径,基于纤维屈曲变形理论和实验结果建立并验证了三者之间的压缩回弹模型。纤维柔性越好,屈曲变形时的曲率半径越小,并且有效纤维长度越长,则气凝胶的压缩回弹率越高。本研究成果为高回弹性SiO2纤维气凝胶的设计制备提供了理论指导。

关键词: 纳米纤维, 柔性, 气凝胶, 回弹机理

Abstract: SiO₂aerogels possess low density, ultralow thermal conductivity and excellent chemical stability, making them suitable for widely application in the fields of aviation and aerospace, building energy conservation, and energy chemical industry. Traditional SiO2 nanoparticle aerogels have large brittleness and poor resilience due to the pearl necklace-like particle structure. Using nanofibers as construction units to fabricate SiO₂ nanofiber aerogels can overcome the brittleness and improve the resilience. However, the resilience mechanism of SiO₂ nanofiber aerogels is still unclear. In the present work, flexible SiO2 nanofibers were prepared by electrospinning. And the effect of calcination temperature on phase microstructure and flexibility was systematically investigated to elucide flexibility mechanism. Subsequently, SiO₂ nanofiber aerogels were fabricated by freeze drying. The influence of solid content on the pore structure, strength and resilience of aerogels was thoroughly studied. A buckling deformation model based on effective nanofiber length was established to elucidate the compressive resilience mechanism. The findings show that calcination temperature affects the amorphous structure and flexibility of SiO₂ nanofibers. The degree of short-range order in SiO₂ increases with the increase in calcination temperature, leading to poor flexibility of nanofibers. The resilience of SiO₂ nanofiber aerogels is related to solid content. The energy loss coefficient and resilient rate of aerogels fabricated with 0.5 wt.% solid content(in mass) are 0.6 and 55.2%, respectively. The resilience of SiO₂nanofiber aerogels is dominated by effective nanofiber length and the curvature radius of nanofibers. Their relationship of resilience model is established and proved through nanofiber buckling theory. With a reduction in curvature radius, achievable through the enhancement of nanofiber flexibility, and an increase in effective nanofiber length, the compressive resilient rate of aerogels increases. The present work provides theoretical guidance for the design of SiO₂nanofiber aerogels with high resilience.

Key words: nanofibres, flexibility, aerogel, resilience mechanism