Influence of carboxylic functionalization of MWCNTs on the thermal properties of MWCNTs/DGEBA/EMI-2,4 nanocomposites

The influence of carboxylic functionalization (COOH-functionalization) of multi-walled carbon nanotubes (MWCNTs) on the thermal properties of MWCNTs/diglycidyl ether of bisphenol A/2-ethyl-4-methylimidazole (MWCNTs/DGEBA/EMI-2,4) nanocomposites was studied using DSC and TGA. The results showed that, at the initial curing stage, activation energy E decreases with increasing curing degree α, moreover, COOH-functionalization of MWCNTs decreases E. Therefore, COOH-functionalization of MWCNTs does not change the autocatalytic cure reaction mechanism of MWCNTs/DGEBA/EMI-2,4 system and has catalytic effect on the curing process. Then, at the later curing stage, carboxylated MWCNTs (COOH-MWCNTs) increase the inflexions of the curves of E vs. α less than purified MWCNTs, indicating that COOH-MWCNTs delay the vitrification less than purified MWCNTs. Furthermore, COOH-functionalization of MWCNTs also improves the thermal stability of nanocomposites.