【摘要】 采用常压干燥法，以环氧丙烷（PO）作为促进剂，通过调整PO与Al的摩尔比，制备出一系列Al₂O₃气凝胶建筑保温材料，研究了PO摩尔比对气凝胶的物相结构、微观形貌、力学性能和保温性能的影响。结果表明，Al₂O₃气凝胶在室温下主要由勃姆石组成，在高温下会逐渐从γ-Al₂O₃相向α-Al₂O₃相转变，而PO摩尔比的增加阻碍了相的转变。Al₂O₃气凝胶由片状小颗粒堆积而成，颗粒尺寸约为85～160 nm。当n（PO）∶n（Al）=5时，气凝胶骨架强度最高，三维网状多孔结构最为致密。随着PO摩尔比的增大，Al₂O₃气凝胶的抗压强度先增大后减小，弹性模量持续增大，导热系数先降低后增大。当n（PO）∶n（Al）=5时，气凝胶的抗压强度达到最大值42.54 MPa,弹性模量为1 454.63 MPa,导热系数最小为0.0954 W/（m·K）,具有优异的保温性能。由此可见，PO的最佳摩尔比为n（PO）∶n（Al）=5。更多还原

【Abstract】 A series of Al₂O₃ aerogel building thermal insulation materials were prepared by atmospheric pressure drying method, using propylene oxide（PO） as accelerator and adjusting the molar ratio of PO to Al. The effects of PO molar ratio on the phase structure, micro morphology, mechanical properties and thermal insulation properties of aerogel were studied. The results show that Al₂O₃ aerogel is mainly composed of Boehmite at room temperature. It gradually changes from γ-Al₂O₃ phase to α-Al₂O₃ phase transition under high temperatures and the increase in PO molar ratio hinders the phase transition. Al₂O₃ aerogel is formed by stacking small flake particles with a particle size of about 85-160 nm. When n（PO） ∶n（Al）=5, the strength of aerogel skeleton is the highest, and the three-dimensional network porous structure is the most compact. With the increase of PO molar ratio, the compressive strength of Al₂O₃ aerogel first increases and then decreases, the elastic modulus continues to increase, and the thermal conductivity first decreases and then increases. When n（PO） ∶n（Al）=5, the maximum compressive strength of aerogel is 42.54 MPa, the elastic modulus is 1 454.63 MPa, and the minimum thermal conductivity is 0.0954 W/（m·K）, which has excellent thermal insulation performance. It can be seen that the optimal molar ratio of PO is n（PO） ∶n（Al）=5.更多还原