Poly(vinyl chloride)-based carbon nanoparticle composites: preparation and microwave properties

Thin-film poly(vinyl chloride) (PVC) composites containing 0.2–30 wt% carbon nanoparticles (CNPs) were prepared by hot pressing. The morphology and elemental composition of the CNPs were analyzed by SEM and EDX, and their thermal stability was evaluated under inert and oxidative atmospheres. FTIR spectroscopy confirmed the absence of any chemical interaction between PVC and CNPs. Ka-band microwave measurements revealed a composition-dependent electromagnetic response. Composites with ≤5 wt% CNPs remained largely transparent to microwaves, whereas higher filler loadings increased reflectivity. The S21 and S11 parameters varied from −0.7 to −2.4 dB and −15.0 to −7.2 dB, respectively, with a transition observed at 10–20 wt% CNPs.