Polymer-assisted dispersion of rGO in cordierite composites for injectable mixtures

Achieving a homogeneous dispersion of graphene-based reinforcements in ceramic matrices remains one of the key barriers to fully exploiting their exceptional mechanical and functional properties. To address this challenge, we explore a solvent-free dispersion strategy based on the polymeric binder phase used in feedstocks for ceramic injection moulding (CIM) and material extrusion (MEX), enabling direct incorporation of reduced graphene oxide (rGO) under scalable, industry-compatible conditions. Cordierite-based ceramics were selected as a case study due to their low thermal expansion and excellent thermal shock resistance, while their limited mechanical performance can potentially be enhanced by graphene reinforcement. Two rGO–binder masterbatch preparation methods were examined: (i) direct blending of rGO into the wax component of the binder, and (ii) ultrasonication-assisted dispersion in the molten wax phase. The masterbatches were subsequently incorporated into the ceramic feedstock. Rheological measurements and differential scanning calorimetry (DSC) were used to evaluate particle–binder interactions, while SEM and Raman spectroscopy assessed microstructural distribution and rGO structural integrity. Though Raman mapping indicated similar defect levels for rGO in both mixing methods, rheological and thermal analyses revealed stronger particle–binder interactions and reduced agglomeration in the ultrasonicated feedstocks. Importantly, the ultrasonication conditions used did not induce measurable structural degradation of rGO. These results demonstrate that polymer-phase ultrasonication is an effective and scalable strategy to improve graphene dispersion in ceramic feedstocks, supporting its broader application across CIM and MEX fabrication routes for high-performance ceramic composites.