Direct Dispersion of Graphene Oxide in Epoxy: Influence Of Processing Route on Thermal, Dynamic-Mechanical, and Impact Properties.

Epoxy matrix nanocomposites reinforced with graphene oxide (GO) have attracted significant interest mainly due to the combination of the nanofiller's exceptional properties with the versatility of epoxy resin, widely used in the aerospace, automotive, sports, and electronics applications. Achieving a homogeneous dispersion of the nanofiller within the polymer matrix remains a crucial challenge, as agglomerates can compromise the material performance. This study comparatively investigates the incorporation of 0.5 wt % GO using different direct dispersion methods into epoxy resin, including manual, mechanical, magnetic stirring, ultrasonic bath, and ultrasonic tip, without organic solvents. The techniques were evaluated in terms of dispersion efficiency and their effects on the mechanical, thermal, and dynamic-mechanical properties of the resulting nanocomposites. The results demonstrated that the used GO concentration enhanced the investigated properties across all dispersion methods. All nanocomposites exhibited an increase in storage modulus compared to pure epoxy resin, with NC4 (157%), NC3 (121%), and NC2 (107%) showing the most significant improvements, indicating enhanced interfacial interactions. Impact resistance was most significantly improved by dispersion via ultrasonic tip, while microscopy analyses (TEM and SEM) effectively characterized and distinguished the dispersion quality achieved by each technique. The ultrasonic tip method led to the most effective dispersion, resulting in a 70.6% increase in impact resistance and a 157% enhancement in storage modulus, evidencing its potential for high-performance nanocomposites.