Fiorini Costanza Vittoria, Merli Francesca, Belloni Elisa, Carroll Mary K, Anderson Ann M, Buratti Cinzia
DIAEE Department of Astronautical, Electrical, and Energy Engineering, "Sapienza" University of Rome, Via Eudossiana 18, 00184 Rome, Italy.
Department of Engineering, University of Perugia, Via G. Duranti 63, 06125 Perugia, Italy.
Gels. 2023 Mar 10;9(3):210. doi: 10.3390/gels9030210.
Due to its excellent properties, monolithic silica aerogel is a promising material for innovative glazing systems. Since glazing systems are exposed to deteriorating agents during building service life, it is essential to investigate the long-term performance of aerogel. In the present paper, several 12.7 mm-thick silica aerogel monoliths produced by a rapid supercritical extraction method were tested, including both hydrophilic and hydrophobic samples. After fabrication and characterization of hydrophobicity, porosity, optical and acoustic properties, and color rendering, the samples were artificially aged by combining temperature and solar radiation effects in an experimental device specifically developed at the University of Perugia. The length of the experimental campaign was determined using acceleration factors (AFs). Temperature AF was evaluated according to the Arrhenius law using thermogravimetric analysis to estimate the aerogel activation energy. A natural service life of 12 years was achieved in about 4 months, and the samples' properties were retested. Contact angle tests supported by FT-IR analysis showed loss of hydrophobicity after aging. Visible transmittance values in the 0.67-0.37 range were obtained for hydrophilic and hydrophobic samples, respectively. The aging process involved optical parameter reduction of only 0.02-0.05. There was also a slight loss in acoustic performance (noise reduction coefficient (NRC) = 0.21-0.25 before aging and NRC = 0.18-0.22 after aging). For hydrophobic panes, color shift values in the 10.2-59.1 and 8.4-60.7 ranges were obtained before and after aging, respectively. The presence of aerogel, regardless of hydrophobicity, results in a deterioration in light-green and azure tones. Hydrophobic samples had lower color rendering performance than hydrophilic aerogel, but this did not worsen after the aging process. This paper makes a significant contribution to the progressive deterioration assessment of aerogel monoliths for applications in sustainable buildings.
由于其优异的性能，整体式二氧化硅气凝胶是创新玻璃系统中一种很有前景的材料。由于玻璃系统在建筑使用寿命期间会受到劣化因素的影响，因此研究气凝胶的长期性能至关重要。在本文中，测试了几种通过快速超临界萃取法制备的12.7毫米厚的二氧化硅气凝胶整体，包括亲水性和疏水性样品。在对疏水性、孔隙率、光学和声学性能以及显色性进行制备和表征后，样品在佩鲁贾大学专门开发的实验装置中通过结合温度和太阳辐射效应进行人工老化。实验周期的长度使用加速因子（AFs）来确定。根据阿伦尼乌斯定律，使用热重分析评估温度加速因子，以估计气凝胶的活化能。在大约4个月内实现了12年的自然使用寿命，并对样品的性能进行了重新测试。FT-IR分析支持的接触角测试表明老化后疏水性丧失。亲水性和疏水性样品的可见光透射率值分别在0.67 - 0.37范围内。老化过程仅使光学参数降低了0.02 - 0.05。声学性能也有轻微损失（老化前降噪系数（NRC）= 0.21 - 0.25，老化后NRC = 0.18 - 0.22）。对于疏水板，老化前后的颜色偏移值分别在10.2 - 59.1和8.4 - 60.7范围内。无论疏水性如何，气凝胶的存在都会导致浅绿色和天蓝色调的恶化。疏水性样品的显色性能低于亲水性气凝胶，但在老化过程后并未恶化。本文对用于可持续建筑的气凝胶整体的渐进劣化评估做出了重大贡献。
