Abstract

This work focuses on characterizing the role of different triblock copolymers on the dispersion of nanoparticles in an epoxy matrix and in the thermal and mechanical properties of the resulting nanocomposites, using Poly (ethylene glycol) - block-poly (propylene glycol) - block-poly (ethylene glycol) (PEG-b-PPG- b-PEG) with 30% PEG, and poly (propylene glycol) - block-poly (ethylene glycol) - block-poly (propylene glycol) (PPG-b-PEG-b-PPG) with 50% PEG. The nanoparticles employed have different geometries: carbon nanotubes, graphene nanoplatelets and carbon black (spherical). Both copolymers were miscible in epoxy. The results suggest that the copolymers viscosity may be interfering with the dispersion of the nanoparticles in the matrix: the PPG-b- PEG-b-PPG50% copolymer has a higher viscosity than the PEG b-PPG-b-PEG30%, which facilitates their dispersion and an increase in mechanical properties. The PEG fraction was an important factor in the dispersion of nanoparticles in the epoxy matrix. The higher the PEG content in the copolymer block, the greater the synergy shown in the mechanical properties, since the nanoparticles inhibited the plasticizing effect of the block copolymer.

Keywords:
Block copolymer; nanocomposites; dispersion; nanoparticles; epoxy