The effect of carbon nanotubes on the curing processes of epoxy-amine compositions

Abstract

The effects of the concentration and functionalization of carbon nanotubes on the degree of conversion of epoxy groups in epoxy-amine compositions based on ED-20 epoxy oligomer and the PEPA curing agent are studied. It has been shown that increasing the concentration of functionalized carbon nanotubes (CNT) from 0 to 0.5 % increases the degree of conversion of the epoxy groups during curing at a room temperature. Further increase in concentration CNT of up to 1 % does not effect on the reaction kinetics. For native CNT not established such a relationship. Explains such a pronounced effect on the f-CNT aminolysis reaction kinetics and ultimate degree of conversion of epoxy groups, apparently, the catalytic effect of oxygen-containing groups (hydroxyl, carboxyl, and others) grafted to the surface of CNTs and their direct involvement in the reaction. By optical microscopy showed that the size of the agglomerates of nanotubes were substantially higher in the native systems than in the system with the functionalized nanotubes. These results may be important for the development of creation of epoxy composites modified by nanoparticles.

Rheology, curing and time‐dependent behavior of epoxy/carbon nanoparticles systems

“…There is an increase in enthalpy above 10% compared to the neat epoxy (346 J/g). This effect can be attributed to a catalytic effect of hydroxyl and carbonyl groups on epoxide ring opening 25,47 …”

“…This effect can be attributed to a catalytic effect of hydroxyl and carbonyl groups on epoxide ring opening. 25,47 The gel content can give an indication of the degree of crosslinking formed. For neat epoxy, it was 85% ± 1%, which increased to 93% ± 1% to 96% ± 1% when adding 0.2 and 1 wt.% of GN, respectively.…”