ZnO surface modification with maleic anhydride using plasma treatment

Zinc oxide (ZnO) was surface treated using argon plasma at 5 and 15 min, using maleic anhydride (MA) in solid state as the functionalizing agent. The samples were characterized by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The results indicate that ZnO surface modification occurs through two main routes: the decomposition of MA and the plasma-induced formation of C–Zn bonds, with 15 min being the most favorable time span. Poly(lactic acid) (PLA) and ZnO were processed in an internal chamber mixer, which was coupled with a torque rheometer and characterized by the Melt Flow Index. Composites containing treated ZnO present fluidity indices closer to those of pure PLA, indicating the functionalization contribution to control the degradation of the polymer matrix.