Preparation,Surface Modification And Application Of Zinc Oxide Nanopowders

Nanomaterial has obtained extensive attentions due to their unique and excellent physical and chemical properties in recent years.In this paper,the aluminum doped zinc oxide(AZO)powders were prepared by a coprecipitation method,which has several advantages such as simplicity,large-scale synthesis,economy and environmental-benign.Additionally,the electrical conductivity and dielectric properties of AZO nanopowders were studied.The surface of AZO nanopowders were modified by organic,inorganic and plasma processing technology,respectively.Moreover,the AZO powders were reinforced into polypropylene(PP)matrix to prepare AZO/PP nanocomposites.The effect of AZO concentrations on the electrical,thermal and mechanical properties of PP composites was investigated.The contents and results are as follows:(1)Preparation and surface modification of zinc oxide nanopowders:The AZO powders were prepared by a coprecipitation method using ZnCl2 and Al(NO3)3 as the raw materials and a mixed alkali solution of NaOH and Na2CO3 was the precipitant.The nanopowders were characterized using IR,TGA,XRD,SEM,EDS,DLS,TEM.The result of XRD and EDS analysis shows that the AZO powders belong to the hexagonal structure and the Zn2+ was replaced by Al3+ to form solid solution.Additionally,the effects of Zn source,Al-doping concentration,pH,different feeding methods and molten salt assisted on electrical conductivity of AZO were investigated.In addition,the effects of oleic acid,silver,plasma process on AZO powder surface modification are studied,respectively.(2)Preparation and characterization of nanocomposite materials:Aluminum-doped zinc oxide(AZO)conductive powders were successfully obtained through an attractive method based on precipitation and plasma processing method.The obtain powders were reinforced into polypropylene(PP)matrix to prepare the nanocomposite materials.The powders were characterized by XRD,TEM,UV-vis,and the dispersion of the AZO filler in the PP matrix was observed by SEM.In addition,the effect of AZO concentrations on the electrical and mechanical properties of PP composites was investigated via resistance measurement,tensile and impact tests,respectively.The results show that the electrical and mechanical properties depend on the concentration and dispersion of AZO nanoparticles in the matrix.The result showed the proper filling concentration(3 wt%)could form effectiveand continuous conductive networks within the PP matrix.Furthermore,the obtained nanocomposites possessed higher thermal stability than neat PP.The tensilestrength of the AZO/PP nanocomposite is improved significantly by the addition of AZO nanoparticles,and the optimal ZnO content is 6.0 wt%.