Mechanical Property of Silica Aerogels Reinforced With Isocyanate

The reinforced silica aerogels with isocyanate were prepared by the method of organic-inorganic-hybrid. The gels were produced by hydrolysis and condensation polymerization of tetramethoxysilane (TMOS), methyltrimethoxysilane (MTMS) and (3-aminopropyl)triethoxysilane (APTES) with water, aged and then immersed in acetonitrile with the monomer of hexamethylene diisocyanate (HDI), supercritically dried by CO₂ to form mechanically strong silica aerogels. In this work, replacing TMOS with some MTMS improves the infiltration between silica gels and HDI. Comparing with oligomer, monomers can infiltrate into the network of gel more easily and make the reaction more amplified, ultimately, forming the nano-scale network more uniform. The good mechanical properties of the reinforced aerogels (compressive modulus 82.37 MPa and compression strength 19.96 MPa) make the machining of aerogels as possible.