Development of sunflower oil‐based nonisocyanate polyurethane/multiwalled carbon nanotube composites with improved physico‐chemical and microwave absorption properties

In this article, we have developed sunflower oil based non‐isocyanate polyurethane (NIPU)/amine functionalized multiwalled carbon nanotube (AF‐CNT) composites. First, carbonated sunflower oil (CSFO) was obtained by solvent‐free mixture reaction of CO₂ with epoxidized sunflower oil under the conditions (120°C, 40 bar) for 10 h, and characterized by FTIR, ¹H NMR and ¹³C NMR. Then, NIPUs were synthesized by reacting the CSFO with isophorone diamine (IPDA) and subsequently, the effects of different weight percentages (0–2 wt%) of AF‐CNTs on physico‐chemical properties of the NIPU/AF‐CNT composites were examined. FT‐IR, XRD and SEM analyses confirmed the formation of the polymer nanocomposites. The results of the studies showed that polymer nanocomposites exhibited better performance than that of pristine polymer. In addition to the improvement in physico‐chemical properties, the electromagnetic interference shielding properties of the composites (1.5 wt% AF‐CNTs) were also calculated in the 8.2–12.4 GHz (X‐band) frequency range with different thicknesses. It is seen that the composite (1.5 wt%) with thickness 3 mm shows the highest microwave absorption with −17 dB at 10.86 GHz. POLYM. COMPOS., 40:E1120–E1130, 2019. © 2018 Society of Plastics Engineers