Effect of thermally reduced graphene oxides obtained at different temperatures on the barrier and mechanical properties of polypropylene/TRGO and polyamide‐6/TRGO nanocomposites

Polypropylene (PP) and polyamide‐6 (PA6) nanocomposites containing thermally reduced graphene oxide (TRGO), obtained either at 600°C (TRGO₆₀₀) or 800°C (TRGO₈₀₀), were prepared by melt mixing in order to study the effect of the thermal treatments on their barrier and mechanical properties. Transmission electron microscopy images of nanocomposites showed a relative good dispersion of TRGO in polymer matrices with some agglomerations. Differential scanning calorimetry analyses showed a slight reduction in crystallinity for both polymers in the presence of TRGO. The permeability to oxygen and water vapor was decreased in almost all nanocomposites due to a more tortuous path to gas permeation, being more evident for PP/TRGO₈₀₀. Tensile stress–strain tests showed that all nanocomposites had higher elastic modulus, but PA6/TRGO₆₀₀ nanocomposites showed better mechanical properties. These findings indicated that TRGO obtained at a higher temperature imparts better barrier and mechanical properties to PP, while TRGO obtained at a lower temperature imparts better barrier and mechanical properties to PA6. POLYM. COMPOS., 40:E1746–E1756, 2019. © 2018 Society of Plastics Engineers