ABSTRACT

In order to better understand the influences of polyimide (PI) skeleton structure and freeze-drying process on the properties of PI aerogel materials, PI molecular chains (ODPA-ODA, BPDA-ODA, BPDA-PPDA) with different stiffnesses and flexibilities were designed and a series of PI aerogels were accordingly fabricated by freeze-drying technique. The aerogels produced featured light weight (density of 0.01–0.16 g/cm³) and high flexibility, and their density, pore structure, and compress recovery performance could be well controlled by delicately tuning the molecular chain structure and solid contents of the poly (amic acid) salt solution. In addition, a hard PI aerogel with enhanced compressive strength was obtained by quick-freezing in liquid nitrogen.

摘要

为了更好地了解聚酰亚胺（PI）骨架结构和冷冻干燥过程对PI气凝胶材料性能的影响，设计了具有不同刚度和柔韧性的PI分子链（ODPA-ODA，BPDA-ODA，BPDA-PPDA）并通过冷冻干燥技术制备了一系列的PI气凝胶。气凝胶的特点是重量轻（密度为0.01-0.16 g / cm ³）和高柔韧性，并且可以通过精细调节聚（）的分子链结构和固含量来很好地控制它们的密度，孔结构和压缩恢复性能。酰胺酸）盐溶液。另外，通过在液氮中快速冷冻获得了具有增强的抗压强度的硬质PI气凝胶。