纳米铜基导电涂料刷涂木材表面可用于电磁屏蔽,但纳米铜颗粒在空气中极易氧化,导致电磁屏蔽性能减弱甚至失效,因此,研究开发柠檬酸-壳聚糖还原体系,以制备尺寸均一、性能稳定的纳米铜.在柠檬酸-壳聚糖体系中,通过液相还原法,用次亚磷酸钠一步还原Cu2+制备抗氧化纳米铜颗粒.探究次亚磷酸钠用量以及柠檬酸浓度对纳米铜粒径、分散性及耐热性的影响,并验证其抗氧化效果.结果表明:在次亚磷酸钠浓度为1.2 wt%、柠檬酸浓度为20 wt%条件下合成的纳米铜的粒径最小,尺寸为160 nm左右,抗氧化性也较好;纳米铜在空气中放置30 d或在160℃下处理2 h,同时多次水洗干燥后再热处理,均未出现氧化现象;在柠檬酸-壳聚糖还原体系下,能够制备出稳定、粒径均一、耐水性良好的纳米铜颗粒,且其具备较强的抗氧化性能.
Nanometer copper based conductive paint brush coated wood surface can be used for electromagnetic shielding,but nanometer copper particles are easy to oxidize in the air,which leads to the weakening of electromagnetic shielding performance or even failure.Therefore,the citrate acid-chitosan redox system was developed in this study to prepare uniform size and stable performance of nano copper.Antioxidant copper nanoparticles were prepared by reducing Cu2+ with sodium hypophosphite in the citrate-chitosan system via liquid phase reduction.The effects of sodium hypophosphite dosage and citric acid concentration on the particle size,dispersibility,and heat resistance of copper nanoparticles were explored and its antioxidant effect was verified.The results showed that the copper nanoparticles synthesized under the condition of sodium hypophosphite concentration of 1.2 wt%and citric acid concentration of 20 wt% had the smallest particle size of about 160 nm and better antioxidant performance.No oxidation of copper nanoparticles has been observed when they were placed in air for 30 d or treated at 160 ℃ for 2 h.The study confirmed that under the citric acid-chitosan redox system,stable copper nanoparticles with uniform particle size and good water resistivity can be successfully obtained,which have strong antioxidant properties.