A simple preparation method of epoxy resin/silica nanocomposite for T-g loss material

摘要

Nanocomposite materials of epoxy resin and silica were prepared by a simple procedure wherein diglycidyl ethers of bisphenol-A (DGEBA) as the pre-polymer of epoxy resin, tetraethoxysilane (TEOS) as silica source, and hexahydrophthalic anhydride (HHPA) were mixed together and heated at 170 degreesC in a sealed autoclave. HHPA played two roles in this reaction system: one role is as a well-known curing reagent of epoxy resin; the other is as the condensation reagent of alkoxysilane, since transesterification promotes this reaction. These two reactions occurred simultaneously in homogeneous solution, and organic - inorganic composite materials were readily obtained. Field emission SEM/EDX images showed that silica particles of nano size ( below 50 nm) were included in the epoxy resin matrix. Some of these epoxy resin/silica nanocomposite materials displayed high thermal stability. When DGEBA bearing about three bisphenol-A units and five molar equivalents of TEOS were reacted, the obtained composite displayed no T-g point below 300 degreesC in the DSC ( differential scanning calorimetry) thermogram. This high thermal stability is likely to be derived from the interaction of hydroxyl groups of DGEBA with silica. [References: 57]