Effraimopoulou Eleni, Jaxel Julien, Budtova Tatiana, Rigacci Arnaud
Mines Paris, PSL University, Centre for Processes, Renewable Energy and Energy Systems (PERSEE), 06904 Sophia Antipolis, France.
Mines Paris, PSL University, Centre for Materials Forming (CEMEF), UMR CNRS 7635, 06904 Sophia Antipolis, France.
Polymers (Basel). 2024 Jun 8;16(12):1628. doi: 10.3390/polym16121628.
Pectin aerogels, with very low density (around 0.1 g cm) and high specific surface area (up to 600 m g), are excellent thermal insulation materials since their thermal conductivity is below that of air at ambient conditions (0.025 W m K). However, due to their intrinsic hydrophilicity, pectin aerogels collapse when in contact with water vapor, losing superinsulating properties. In this work, first, pectin aerogels were made, and the influence of the different process parameters on the materials' structure and properties were studied. All neat pectin aerogels had a low density (0.04-0.11 g cm), high specific surface area (308-567 m g), and very low thermal conductivity (0.015-0.023 W m K). Then, pectin aerogels were hydrophobized via the chemical vapor deposition of methyltrimethoxysilane using different reaction durations (2 to 24 h). The influence of hydrophobization on material properties, especially on thermal conductivity, was recorded by conditioning in a climate chamber (25 °C, 80% relative humidity). Hydrophobization resulted in the increase in thermal conductivity compared to that of neat pectin aerogels. MTMS deposition for 16 h was efficient for hydrophobizing pectin aerogels in moist environment (contact angle 115°) and stabilizing material properties with no fluctuation in thermal conductivity (0.030 W m K) and density for the testing period of 8 months.
果胶气凝胶密度极低(约0.1 g/cm³)且比表面积高(高达600 m²/g),是优异的隔热材料,因为其在环境条件下的热导率低于空气(0.025 W/(m·K))。然而,由于其固有的亲水性,果胶气凝胶在与水蒸气接触时会坍塌,失去超隔热性能。在这项工作中,首先制备了果胶气凝胶,并研究了不同工艺参数对材料结构和性能的影响。所有纯果胶气凝胶密度低(0.04 - 0.11 g/cm³)、比表面积高(308 - 567 m²/g)且热导率极低(0.015 - 0.023 W/(m·K))。然后,使用不同反应时长(2至24小时)通过甲基三甲氧基硅烷的化学气相沉积对果胶气凝胶进行疏水化处理。通过在气候室(25°C,80%相对湿度)中进行调节,记录了疏水化对材料性能,特别是对热导率的影响。与纯果胶气凝胶相比,疏水化导致热导率增加。在潮湿环境中(接触角115°),甲基三甲氧基硅烷沉积16小时对于果胶气凝胶的疏水化是有效的,并且在8个月的测试期内材料性能稳定,热导率(0.030 W/(m·K))和密度无波动。