Preparation of resorcinol-formaldehyde aerogel hollow microspheres
Based on the technique of micro fluid injection molding,RF hollow microspheres were synthesized by using dibutyl phthalate as oil phase,RF solution as water phase,and by sol-gel,solvent exchanging and supercritical drying.The components,morphology,aperture,and diameter distribution of RF hollow microspheres were characterized by infrared spectrum,X-ray micro analysis,TEM,and nitrogen adsorption-desorption respectively.The results show that RF hollow microsphere is monolayered and has a typical structure of the porous aerogel.The pores are consisting of nearly uniform nano-particles about 10 nm in diameter,and their average aperture is about 20 nm.The sphericity and concentricity of the monolayer hollow microsphere is higher than 95%,the diameter distribution of RF hollow microspheres is in the range of 550~750 μm,and the maximum diameter reaches 800 μm,which satisfies the requirement of fast ignition.