Water-Borne Thermal Insulating Polyimide Aerogels with Hierarchical Porous Hyper-Cross-Linked Structure
발표자
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초록
내용
Polyimide aerogel, a type of highly porous material with low density, excellent insulation performance, high specific surface area and strength has application in the fields of thermal insulation and aerospace. Generally, polyimide aerogels are synthesized by reacting diamines and dianhydrides in organic solvents, which can cause environmental pollution. Meanwhile, water is easy to handle and safe, making it possible to synthesize polyimide aerogel in an eco-friendly. Since the dianhydride and diamine were still soluble in organic solvents, organic base was added to convert poly(amic acid) into salt, enabling synthesis in water. Water soluble poly(amic acid) salt eliminate the need for solvent exchange process before aging and freeze-drying, making aerogels convenient and environmentally friendly. During thermal imidization and freeze-drying, the solvent evaporates, which causes shrinkage. To solve these problem, we added mesoporous silica which serves as a cross-linker.