Expanded vermiculite is an important thermal insulation material with layered micro-porous structure.In this paper,we adopted in situ gel method to modify the microstructure of expanded vermiculite,and researched the conditions for the preparation processes of modified expanded vermiculite.The optimized proportion of in situ gel modification is:n(epoxy propane)∶n(Al) ∶ n(alcohol) =5.5∶1∶30.As shown in the SEM micrographs of expanded vermiculite modified by in situ aluminum gel,the framework of in situ aluminum gel is made up of sphere-like Al2O3 particles.The particle size is fairly uniform,and the mean particle diameter is 40 nm.Besides,the pore size is about 45 nm,and the pore size distribution is quite uniform.After being calcined under the temperature of 900 °C and 1000 °C for 4 hours,the modified vermiculite can still keep a good multi-porous network structure,without any distinct signs of conglobation or collapse of porous structure.
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