Effects of the amine/epoxy stoichiometry on the curing behavior and glass transition temperature of MWCNTs-NH2/epoxy nanocomposites

• Effects of amine/epoxy stoichiometry on curing behavior of MWCNTs-NH2/epoxy systems were studied.
• The catalytic effect of MWCNTs-NH2 was weakened by increasing amine/epoxy stoichiometry.
• For the system with excess epoxy, the etherification reaction was promoted by adding MWCNTs-NH2.
• The moderate excess epoxy was proposed as an essential prerequisite to enhance the Tg of MWCNTs-NH2/epoxy systems.

In this study, amine functionalized multi-walled carbon nanotubes (MWCNTs-NH2) with surface covalently linked ethylenediamine were prepared. The effect of amine/epoxy stoichiometry on the curing behavior, cross-linking network structure and glass transition temperature (Tg) of MWCNTs-NH2 reinforced epoxy-amine systems were investigated by using non-isothermal differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) and dynamic mechanical analysis (DMA), respectively. The results indicated the catalytic effect MWCNTs-NH2 in the curing process of epoxy was weakened with the increase of amine/epoxy stoichiometry, which can affect the formation of cross-linking network and Tg of the cured MWCNTs-NH2/epoxy nanocomposites contrasted with the corresponding neat epoxy. The MWCNTs-NH2/epoxy composites with moderate excess epoxy equivalent exhibited higher Tg than that of the neat epoxy, which was attributed to the excess epoxy groups can promote the etherification reaction as well as the interfacial interaction between MWCNTs-NH2 and epoxy resin.

Figure optionsDownload as PowerPoint slide