Zhang Sizhao, Yang Zhouyuan, Huang Xing, Wang Jing, Xiao Yunyun, He Junpeng, Feng Jian, Xiong Shixian, Li Zhengquan
Polymer Aerogels Research Center, Jiangxi University of Science and Technology, Nanchang 330013, China.
Postdoctoral Research Station on Mechanics, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China.
Gels. 2022 Oct 19;8(10):671. doi: 10.3390/gels8100671.
As naturally derived material, cellulose aerogels have excellent thermal insulation properties due to their unique high porosity and three-dimensional mesoporous structure. However, its hydrophilic properties limit its application in the field of building insulation. Here, we propose a method to prepare high hydrophobicity by adopting the sol-gel method and chemical vapor reaction strategy using cellulose acetate type II as raw material and 2,4-toluene diisocyanate as the cross-linking agent. Thermal properties of cellulose acetate aerogels (CAAs) were measured, where pyridine was the catalyst, acetone was the solvent, and perfluorodecyltriethoxysilane (PFDS), hexamethyldisilazane (HMDS), and methyltriethoxysilane (MTES) were used as hydrophobic agents (by process hydrophobic test). Compared with MTES-modified cellulose acetate aerogels (M-CAAs) and HMDS (H-CAAs)-modified cellulose acetate aerogels, PFDS-modified (P-CAAs) cellulose acetate aerogels are the most hydrophobic. By implementing hydrophobic modification of PFDS both inside and outside the structure of cellulose acetate aerogels, the water contact angle can reach up to 136°, strongly demonstrating the potential of PFDS as a hydrophobic agent. The results show that the thermal conductivity and compressive strength of cellulose acetate aerogel with the best hydrophobic properties are 0.035 W m K at normal pressure and 0.39 MPa at 3% strain, respectively. This work shows that the highly hydrophobic cellulose acetate aerogel has potential as a waterproof material in the field of building thermal-insulation materials.
作为天然衍生材料，纤维素气凝胶因其独特的高孔隙率和三维介孔结构而具有优异的隔热性能。然而，其亲水性限制了它在建筑隔热领域的应用。在此，我们提出一种方法，以II型醋酸纤维素为原料，2,4-甲苯二异氰酸酯为交联剂，采用溶胶-凝胶法和化学气相反应策略来制备高疏水性材料。测量了醋酸纤维素气凝胶（CAA）的热性能，其中吡啶为催化剂，丙酮为溶剂，全氟癸基三乙氧基硅烷（PFDS）、六甲基二硅氮烷（HMDS）和甲基三乙氧基硅烷（MTES）用作疏水剂（通过疏水性测试）。与MTES改性的醋酸纤维素气凝胶（M-CAA）和HMDS改性的醋酸纤维素气凝胶（H-CAA）相比，PFDS改性的（P-CAA）醋酸纤维素气凝胶疏水性最强。通过在醋酸纤维素气凝胶结构内外实施PFDS疏水改性，水接触角可达136°，有力地证明了PFDS作为疏水剂的潜力。结果表明，疏水性最佳的醋酸纤维素气凝胶在常压下的热导率和在3%应变下的抗压强度分别为0.035 W m K和0.39 MPa。这项工作表明，高度疏水的醋酸纤维素气凝胶在建筑保温材料领域具有作为防水材料的潜力。
