Impact of co-mixing technique and surface modification of ZnO nanoparticles using stearic acid on their dispersion into HDPE to produce HDPE/ZnO nanocomposites

In this article, the effectiveness of the co-mixing processing technique and surface modification of zinc oxide (ZnO) filler on the characteristics of the developed high-density polyethylene (HDPE)/ZnO was investigated. ZnO was treated and co-mixed with stearic acid (SA) at a ratio of 50/50 wt% using kitchen coffee grinder and the mixture was then added to the HDPE matrix in a Brabender plastograph with various ZnO contents of 0.5, 1 and 2 wt%. The morphology of the nanocomposites was characterized using scanning electron microscopy (SEM). The micrographs showed well and uniform dispersion of both treated and untreated ZnO nanofiller; however, the treated ZnO particles showed better dispersion. The nanocomposite containing 1 wt% ZnO nanoparticles was found to have the optimal properties. The results of the SEM were supported by the atomic force microscopic technique. The uniform dispersion of ZnO was further investigated through X-ray diffraction spectra. The minor peaks of ZnO in the HDPE/treated and untreated ZnO nanocomposites are considered as an evidence for the presence of uniform and well-dispersed ZnO. The electrical conductivity of the nanocomposite samples is higher than that of neat HDPE due to the semiconducting nature of ZnO and increases with ZnO content. The results of this work proved that dispersibility can be achieved through the addition of SA and conductivity of the nanocomposite depends on the ZnO content. Moreover, co-mixing technique and the surface modification of the nanofillers are very effective in producing the HDPE/ZnO nanocomposites that have many potential industrial applications such as food packaging, drug and pharmaceutical bottles.