Zhang Sizhao, Xiao Qi, Xiao Yunyun, Li Zhengquan, Xiong Shixian, Ding Feng, He Junpeng
Polymer Aerogels Research Center, Jiangxi University of Science and Technology, Ganzhou 341000, China.
Postdoctoral Research Station on Mechanics, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China.
Gels. 2022 Feb 18;8(2):131. doi: 10.3390/gels8020131.
Chitosan (CTS) aerogel is a new type of functional material that could be possibly applied in the thermal insulation field, especially in energy-saving buildings. However, the inhibition method for the very big shrinkage of CTS aerogels from the final gel to the aerogel is challenging, causing great difficulty in achieving a near-net shape of CTS aerogels. Here, this study explored a facile strategy for restraining CTS-based aerogels' inherent shrinkage depending on the chemical crosslinking and the interpenetrated supramolecular interaction by introducing nanofibrillar cellulose (NFC) and polyvinyl alcohol (PVA) chains. The effects of different aspect ratios of NFC on the CTS-based aerogels were systematically analyzed. The results showed that the optimal aspect ratio for NFC introduction was 37.5 from the comprehensive property perspective. CTS/PVA/NFC hybrid aerogels with the aspect ratio of 37.5 for NFC gained a superior thermal conductivity of 0.0224 W/m K at ambient atmosphere (the cold surface temperature was only 33.46 °C, despite contacting the hot surface of 80.46 °C), a low density of 0.09 g/cm, and a relatively high compressive stress of 0.51 MPa at 10% strain.
壳聚糖（CTS）气凝胶是一种新型功能材料，有望应用于保温领域，特别是在节能建筑中。然而，抑制CTS气凝胶从最终凝胶到气凝胶的大幅收缩的方法具有挑战性，这给实现CTS气凝胶的近净形状带来了很大困难。在此，本研究探索了一种简便策略，通过引入纳米原纤化纤维素（NFC）和聚乙烯醇（PVA）链，依靠化学交联和互穿超分子相互作用来抑制基于CTS的气凝胶的固有收缩。系统分析了不同长径比的NFC对基于CTS的气凝胶的影响。结果表明，从综合性能角度来看，引入NFC的最佳长径比为37.5。NFC长径比为37.5的CTS/PVA/NFC混合气凝胶在环境大气中具有0.0224 W/m K的优异热导率（尽管与80.46°C的热表面接触，但冷表面温度仅为33.46°C）、0.09 g/cm的低密度以及在10%应变下0.51 MPa的相对较高压缩应力。
