The effects of carbon nanoparticles on curing kinetics of epoxy modified with triblock copolymer

Abstract

This work studies the effects of combining triblock copolymers with carbon nanoparticles (carbon nanotubes, graphene and carbon black) on curing kinetics. The chosen triblock copolymer was poly (propylene glycol)-block-poly (ethylene glycol)-block-poly (propylene glycol) (PPG-b-PEG-b-PPG), which has different contents of PEG in its structure. The main objective is to investigate the influence of the miscibility of the PPG-b-PEG-b-PPG copolymer in epoxy nanocomposites. The PEG fraction in the copolymer structure was determinant for miscibility. The copolymer with the highest PEG fraction (50%) in its structure showed miscibility. The copolymer miscibility was critical for nanoparticle–matrix synergy, and the PPG-b-PEG-b-PPG copolymer nanocomposite with 50 wt% PEG showed a greater increase in E’ in relation to the nanocomposite with PPG-b-PEG-b-PPG with 10% by weight of PEG. Cure kinetics results showed that the incorporation of carbon nanoparticles delays the kinetics as the temperature increases. Additionally, the miscible block copolymer delayed the curing reaction, whereas the immiscible one accelerated it, even with the addition of nanoparticles. Finally, DSC analysis allowed to verify that the cure kinetics of all studied copolymer nanocomposite systems satisfy Kamal’s autocatalytic model.