12 Aug 2025

Carbon Nanotube-Based Segregated Thermoplastic Nanocomposites Structured via Electromagnetic Melt Processing

Abstract: The EM-processed TPNCs prepared with EM-susceptible carbon nanotubes exhibited a significant enhancement in transport and mechanical properties, outperforming conventionally processed TPNCs. Thus, EM-processed TPNCs demonstrated an ultralow electrical percolation threshold and a remarkable increase in volume electrical conductivity of 8 orders of magnitude at only 1.0 wt % CNT loading. This highlights the superior network formation, level of segregation, and structuring enabled by EM processing. Differential scanning calorimetry and X-ray diffraction revealed EM-processed TPNCs exhibited higher crystallinity and a predominantly α crystal phase compared to hot-pressed TPNCs. Microstructural inspection by electron microscopy disclosed EM processing led to segregated but interconnected multiscale networks of a thin and well-defined CNT interphase that encompassed from the nanoscale of CNTs to the macroscopic scale of TPNCs. The EM-processed TPNCs developed a statistically higher stiffness and in certain cases, even better strength than hot-pressed TPNCs. However, EM-processed TPNCs displayed significantly lower ductility, owing to their higher crystallinity, more brittle crystal α phase, and potential formation of microvoids in the bulk of the TPNCs inherent to the unoptimized EM processing. This work provides an understanding of an alternative and unconventional processing method capable of achieving higher structuring in nanocomposites with advanced multifunctional properties.