UV-cured poly(urethane acrylate) composite films containing surface-modified tetrapod ZnO whiskers

Surface-modified tetrapod zinc oxide whiskers (STZnO-W) were successfully synthesized via a thermal oxidation method and subsequent modification using a silane coupling agent and were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (WAXD) and scanning electron microscopy (SEM). Five different poly(urethane acrylate) (PUA)/STZnO-W composite films containing the as-synthesized STZnO-W were prepared via a UV curing method. The morphology, thermal stability, mechanical properties, barrier properties, and antibacterial properties of these films were investigated as a function of the STZnO-W content and were found to be strongly dependent upon the chemical and morphological structures. The thermal stability, barrier properties, and antibacterial properties of the composite films were enhanced as the STZnO-W content increased, which indicate that these materials are potentially suitable for many packaging applications. Barrier tests showed that the oxygen transmission rate (OTR) and water uptake decreased from 724.3 g/cc/day to 176.0 g/cc/day and 3.7–0.7 wt.%, respectively. Although the mechanical strength increased to 1 wt.% STZnO-W content, it decreased at relatively high STZnO-W loadings due to low interfacial interaction between polymer and filler and the resulting poor dispersion. Therefore, further studies are needed to maximize the performance of composite films by enhancing the compatibility of the polymer matrix and fillers.