Design of polyurethane composite foam obtained from industrial PET wastes and MXenes for EMI shielding applications†

The primary aim of this study was to synthesize and characterize polyurethane (PUR) foams derived from the depolymerization products of poly(ethylene terephthalate) (PET) and MXenes (Nb₂AlC). The depolymerized PET products were produced through a zinc acetate-catalyzed glycolysis process using diethylene glycol (DEG) as solvent. These glycolysis products were then reacted with 4,4′-diphenylmethane diisocyanate (MDI), commercial polyols, and MXenes to produce the PUR foams. The resulting materials were characterized using FT-IR, SEM, EDX mapping, mechanical testing, thermal analysis, and electromagnetic interference (EMI) shielding assessments. The analysis revealed that specimens with a higher concentration of the filler (3.55%) exhibited superior mechanical properties, while the thermal behavior remained relatively unchanged. The sample containing 2.56% of MXenes showed significant potential as an effective EMI shielding material in the 8–9 GHz frequency range, while the blank sample provided the best performance between 9–13 GHz, mostly due to a bigger high-frequency absorption in the upper part of the X band. Regarding mechanical performance, the compression force increased slightly from 1013.31 N to 1013.71 N as the Mxenes concentration increased from 2.56% to 3.55%.