Study On The Preparation Of Nano-ZnO And Its Polymer Composites

Nano-ZnO with diameters of 8~130nm were prepared from zinc nitrate and urea by homogeneous precipitation method. The results of the study on the processes of precipitation and the followed calcination indicated that the shape and size of the precursor influenced the product obviously. The precursors with shapes of bar or lamellar were obtained by controlling the reaction conditions, and accordingly, the product of nano-ZnO with different shape and size could be obtained. TEM, AFM, XRD,TG-DTA and Laser particle size analyzer were used to characterize and compare the precursor and nano-scaling products. The results showed that the precursor played an important role on the products and the calcination process had directly influenced on the quality and the shape of the products.The middle infrared, ultraviolet-visible light absorption behaviors of nano-ZnO were investigated and compared with commercial ZnO powder. The results indicated that nano-ZnO and commercial ZnO powder had almost the same absorption abilities in middle infrared band. The nano-ZnO had high transparence property in the band of visible light, while the commercial ZnO powder was opaque. At the same time, nano-ZnO had wide absorption frequency as well as good absorption effect within the ultraviolet band. With the decreasing of the diameter of nanometer particle, blue shift of absorbing peak was observed. Further study showed that quanta size effect is the reason of ultraviolet absorption and blue shift ofabsorption peak.The prepared nano-ZnO was used in NR-SBR-BR composites, the investigation showed that the vulcanization would be proponed when very small amount of nano-ZnO was added. However, as more nano-ZnO was added and the smaller the particle size was, the shorter the vulcanization time was. On the other hand, when commercial ZnO powder was insteaded by nano-ZnO, the mechanic properties would be improved and the needed quantity of ZnO would be decreased. Compared with rubber composites with 5 parts of commercial ZnO powder, rubber composites with only 1 parts of nano-ZnO have better mechanic properties, wear-resistance and anti-aging ability. When quantity of nano-ZnO increased, the rubber composite materials appeared good effect on enhancing the anti-aging ability and wear-resistance but less on mechanic properties.Nano-ZnO modified by coupling agent was applied to reinforcement of HOPE. Mechanic properties of nano-ZnO/HDPE composites were investigated and compared with nano-ZnO without surface treatment. The results indicated that the mechanic properties of composites were improved obviously when 1~3% of nano-ZnO was used. However, as the content of nano-ZnO was over 3%, the mechanic properties decreased contrarily. The results also showed that nano-ZnO without surface treatment had no effect on strengthening and toughening the composites.