High shear mechanochemical treatment enables multifunctional CNT polycarbonate nanocomposites

Mechanochemical treatment can offer a sustainable, solvent-free approach for developing polymer nanocomposites by activating and dispersing nanofillers through mechanical energy instead of chemical reagents. Mechanochemical treatment enhances interfacial interactions, minimises structural damage and enables scalable processing of multifunctional materials. In this work, a solvent-free mechanochemical strategy was developed to address the entanglement and agglomeration of multi-walled carbon nanotubes (MWCNTs) in polycarbonate (PC) matrices. We compared two distinct mechanochemical approaches: (i) conventional impact-driven ball milling and (ii) a shear-dominated kitchen-blender process. Both methods effectively disentangled CNT bundles to varying degrees. During disentanglement, polycarbonate (PC) powder was introduced, enabling uniform coating of CNTs onto PC particles; this experimental design prevented CNT re-agglomerating during drying and ensured stable dispersion throughout the subsequent melt-compounding process. Structural and morphological analyses confirmed that the blender method achieved the most effective disentanglement with minimal defect generation. Consequently, the resulting PC/KBCNT nanocomposites exhibited outstanding multifunctional properties, including a 35% increase in tensile strength (88.6 MPa), 77% higher thermal conductivity, ten orders of magnitude lower resistivity and electromagnetic interference shielding effectiveness up to 24.2 dB at 20 wt % CNT loading. This work demonstrates that high-shear mechanochemistry provides a scalable and environmentally benign route to develop high-performance polymer/CNT nanocomposites with structure–property relationships.