Tuning the\nMorphology of Immiscible Polymer Blend-Based\nHybrid Nanocomposite for Improving Microwave Absorption Response

Polymer-blend-based nanocomposites incorporating carbon\nnanomaterials\nhold significant potential for microwave absorption materials (MAM)\napplications. This study investigates the microwave absorption response\nof hybrid nanocomposites composed of multiwalled carbon nanotubes\n(MWCNT) and nanographite, prepared using industrial-like melt-mixing\nmasterbatch strategies in a polycarbonate/acrylonitrile-butadiene-styrene\ncopolymer (PC/ABS) blend matrix with varying blend ratios (100/0,\n80/20, 60/40, 50/50, 40/60, 20/80, and 0/100) and a constant filler\ncontent (2 wt % MWCNT and 2 wt % nanographite). Furthermore, the PC/ABS\n(40/60) blend-based nanocomposite was prepared with the addition of\na compatibilizer, 5 wt % of maleic anhydride grafted ABS (ABS-<i>g</i>-MAH), to verify possible changes in morphology. Morphology,\nrheology, mechanical, electrical, and electromagnetic properties were\ncorrelated. From a morphological perspective, a preferential distribution\nof MWCNTs within the PC phase was observed, with the different blend\nratios leading to a transition from a dispersed matrix morphology\nin 80/20 and 20/80 (PC/ABS) to cocontinuous morphologies in the intermediate\nblends (60/40, 50/50, and 40/60). The addition of ABS-<i>g</i>-MAH as a compatibilizer resulted in significant morphological refinement.\nElectromagnetic properties, evaluated using both X-band rectangular\nwaveguide and broadband coaxial airline techniques, as well as electrical\nconductivity, were found to be strongly influenced by the varying\nmorphologies. The nanocomposite PC/ABS/ABS-<i>g</i>-MAH\nwith a thickness of 3.0 mm presented a Reflection Loss (RL) of −29.4\ndB at 9.44 GHz, with a bandwidth of 3 GHz. Across the broadband spectrum,\nRL values below −10 dB were observed, including at lower frequencies\naround 3.70 GHz. These findings suggest that morphological tuning\nof the polymer matrix offers a promising pathway for optimizing microwave\nabsorption in hybrid nanocomposites.