Effect of amine-functionalized silica nanoparticles on thermal and mechanical behaviors of DGEBA/IPD epoxy networks

In this work, diglycidyl ether of bisphenol A (DGEBA) epoxy resin was cured by isophorone diamine (IPD) hardener in the presence of amine-functionalized silica nanoparticles. Depending upon the aminated silica (AS) contents, two epoxy networks labeled by EP/AS-2.5 and EP/AS-5.0 were obtained. The amine functional groups can allow the nanoparticles to be covalently incorporated into the epoxy matrix. Two controls, including epoxy network loaded by pristine silica (EP/S-2.5) as well as neat epoxy network, were also prepared via a similar protocol. Thus, thermal and mechanical behaviors of the resulting materials were studied as a function of silica surface characteristics, i.e., hydrophilic vs. organo-modified surface, and its loading content. The initial decomposition temperatures (T _IDT) and the temperatures of the maximum decomposition rate (T _max) were improved. The AS nanoparticles could enhance the storage moduli (E′ values) of the epoxy networks at high-temperature region. Dynamic mechanical analyses also showed that the amine-functionalization of silica can lead to a superior interaction between the nanoparticles and the resulting DGEBA/IPD epoxy networks.