Morphological, thermomechanical and thermal behavior of epoxy/MMT nanocomposites

• The increase in mixing time caused an improvement in the level of dispersion of the clay.
• The addition of the MMT in the epoxy resin did not change the kinetic mechanism significantly.
• The curing kinetics of the polymer systems are controlled by random and diffusion mechanisms.
• The master curve successfully describes the cure kinetics of the epoxy resin.

The present work reports the influence of the MMT content in the dispersing and exfoliating method of the nanofillers on non-isothermal cure behavior, morphology and solid viscoelastic properties of the epoxy resin/MMT systems were determined. The curing kinetics of the polymer systems are controlled by random and diffusion mechanisms. The amount of MMT content does not change the type of mechanism, but it has influence on the reaction enthalpy values and peak. The nanocomposite morphology indicated that the increase in mixing time caused an improvement in the level of dispersion of the clay. The use of ultrasonication decreases the dispersion of MMT in the epoxy matrix. The amount of MMT influences the delamination and uniformity of the matrix and consequently, the systems with 5 wt.% of MMT exhibited greater homogeneity than those containing 3 wt.%. The nanocomposites prepared without ultrasonication showed two peaks in tan δ, which might be related to the consequent formation of regions with different levels of clay distribution and heterogeneities. The storage modulus of the obtained nanocomposites decreased compared to the epoxy matrix. This may be related to the contribution of the interphase region, side reactions, and plasticizing effects of the organic modifier of the clay.