Thermal properties and non-isothermal curing kinetics of carbon nanotubes/ionic liquid/epoxy resin systems

• Alkyl imidazole ionic liquid [BMIM]PF6 was used as a dispersing agent for CNTs/epoxy resin.
• The activation energy and two-parameter autocatalytic equations of Šesták–Berggren model for two systems were constructed.
• TGA and DSC were used to measure the thermal properties of the composites.
• The glass transition temperature of CNTs/ILs/EP was 32 °C higher than that of CNTs/EP.

Nanocomposites of multi-wall carbon nanotubes in diglycidyl ether of a bisphenol A epoxy matrix were prepared using ionic liquid [BMIM]PF6 as a dispersion agent and diaminodiphenyl methane as a hardener. The non-isothermal curing kinetics of the neat EP, CNTs/EP and CNTs/ILs/EP were investigated, and the activation energy was calculated using the Kissinger equation. Two-parameter autocatalytic equations of Šesták–Berggren model were constructed to describe the curing reaction rate quantitatively. The reaction orders, pre-exponential factor A and kinetic model f(α) were determined by curve fitting, and the calculated curves described the observed reaction rate well. TGA and DMA were used to measure the thermal properties of the composites. Adding ILs increased the storage modulus of composites, but decreased the thermal stability. Fracture surfaces of CNTs/EP and CNTs/ILs/EP composites were observed by SEM. CNTs showed better dispersion state in CNTs/ILs/EP composites.