Nanocomposites of Recycled Polycarbonate/Nano-Zinc Oxide (rPC/nZnO): Effect of Nanofiller and Gamma-Radiation on the Properties and as Barrier Against Ultraviolet Light

Abstract

In order to promote barrier against ultraviolet radiation and increase of mechanical characteristics performance, nanocomposites of recycled polycarbonate/nano-zinc oxide (rPC/nZnO) with different nZnO content were prepared and submitted to doses of gamma-radiation (10–50 kGy). The nanocomposites were also exposed to Xenon light source in a weather chamber viewing to evaluate the action of nZnO against ultraviolet light. The rPC/nZnO nanocomposites were characterized by thermogravimetry (TGA), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and infrared spectrometry (FT-IR). There was a progressive reduction of the glass transition temperature (T g) and degradation temperatures, T onset and T max, as function of gamma-radiation dose and nano-zinc oxide content. The lowering of the thermal properties was attributed to the alcoholysis reaction between hydroxyl groups onto the nZnO surface and carbonate linkages of the rPC during the molten state. WAXD revealed a possible chains arrangement (induction of crystallinity) and/or segregation of chains size (scission of rPC chains generating oligomers) associated to the alcoholysis reaction. The action of gamma-radiation as crosslinking agent was not effective. The degree of swelling is zero on account of the stabilization of rPC radicals by oxygen during gamma-radiation exposure. Before exposure to UV light the carbonyl index (CI) show trend to decrease—corroborating the scission of the rPC carbonate bonds. After 100 hours of exposure a recovering of the CI was noticed. The result was associated to the free radicals recombination and esterification reactions. In some extent the combined action of nZnO and gamma-radiation as barrier to UV light was successful.

Incorporation of Nano-Zinc Oxide in Lamellar Zirconium Phosphate: Synthesis and Characterization

“…Synergic action of ZnO nanoparticle and gamma-radiation in recycled polycarbonate as barrier against ultraviolet radiation was studied. The authors considered that the combined action of nanofiller and irradiation as barrier to UV was satisfactory [2]. The action of ZnO nanoparticles antibacterial agent was reviewed.…”