微乳液聚合制备纳米银/聚苯乙烯复合材料

Preparation of nano-silver/polystyrene composite via microemulsion polymerization

采用柠檬酸钠为稳定剂、聚乙烯吡咯烷酮为分散剂,以水合肼还原银氨络离子制备出稳定的单分散胶态纳米银。以制得的纳米银溶胶,通过正相微乳液聚合,制备纳米银/聚苯乙烯复合材料。利用紫外-可见光(UV-Vis)吸收光谱研究了纳米银的光吸收特性,采用X射线衍射(XRD)和透射电镜(TEM)对产物的晶体结构、形貌及尺寸进行了分析。结果表明:所制得的银纳米颗粒属立方晶系,平均粒径约10nm,且无团聚及氧化现象;聚合过程中,纳米银的晶体结构、形貌及尺寸未发生明显变化。凝胶渗透色谱(GPC)分析表明聚苯乙烯基体重均分子量达4.03×106,分子量分布指数为1.21;热重-示差扫描量热(TG-DSC)分析表明所制备的复合材料具有优异的热稳定性。

High stable and monodisperse colloidal nano-silver particles were synthesized by reduction of [Ag（NH3）2]^＋ with hydrazine hydrate using sodium citrate as stabilizer and polyvinylpyrrolidone（PVP） as dispersant. Furthermore, nano silver/poly- styrene composite was prepared via microemulsion polymerization. The optical properties of the nano-silver particles were studied by ultraviolet-visible （UV Vis） absorption spectra, and the crystal structure and microscopic morphology were characterized via X-ray diffraction（XRD） and transmission electron microscopy（TEM）, respectively. Results show that, the nano-silver particles belong to cubic crystal system and have an average diameter of 10 nm without aggregation and oxidation, and their crystal struc- ture and microscopic morphology do not change obviously during the process of polymerization. Gel permeation chromatography （GPC） data shows that the weight-average molecular weight of polystyrene matrix is over 4.03× 106 , and the molecular weight distribution index is 1.21. Thermal gravity-differential scanning calorimetry（TG-DSC） test demonstrates that the nano-silver/pol- ystyrene composite has excellent thermal stability.