电纺制备氧化锆空心微球的工艺研究

Preparation of zirconia hollow microspheres by electrospinning

为了获得直径较为均一、空心率较大的氧化锆空心微球,以八水氯氧化锆为原料,六水硝酸钇为稳定剂,聚乙烯吡咯烷酮(PVP)为助纺剂,无水乙醇和N,N-二甲基甲酰胺(DMF)为溶剂,采用电纺法制备出氧化锆-PVP前驱体球,经1 000℃煅烧后得到氧化锆空心微球。研究了PVP用量(加入质量分数分别为10%、15%和20%)、电纺电压(分别为15、20和25 k V)以及DMF与乙醇体积比(分别为1.675、0.618、0.2、0.1和0.05)对所制备氧化锆空心微球物相组成和显微形貌的影响。结果表明:仅以乙醇为溶剂制备的氧化锆空心球空心率较大,但直径分布不均匀。随PVP用量增大,试样获得纯的t-Zr O2晶相,PVP用量为10%(w)时出现m-Zr O2晶相;电纺电压过小会导致空心球的粘连,过大则生成了粒状的氧化锆颗粒。当电纺电压为20 k V,PVP用量为15%(w)时,制备出高纯t-Zr O2空心球。随着DMF与乙醇比例的减小,氧化锆空心球的球形度变好,直径变得均一;DMF与乙醇体积比为0.1时,制备出的氧化锆空心球直径约350 nm,壁厚和内径分别约为84和266 nm,具有明显空心结构。

To prepare the zirconia hollow microspheres with uniform diameter and high hollowness rate,zirconium oxychloride octohydrate was used as the starting material,yttrium nitrate hexahydrate as the stabilizer,polyvinyl pyrrolidone（PVP） as the spinning aid,and anhydrous ethanol and dimethylformamide（DMF） as the solvents. The zirconia hollow microspheres were obtained at 1000 ℃ by calcining the zirconia/PVP precursor balls prepared by electrospinning. The effects of PVP addition（10%,15% and 20% by mass）,electrospinning voltage（15,20 and 25 k V）,and the volume ratio of DMF to ethanol（1. 675,0. 618,0. 2,0. 1 and 0. 05）on phase composition and microstructure of the prepared zirconia hollow microspheres were systematically investigated. The results show that when only using anhydrous ethanol as the solvent,the hollow rate of the zirconia hollow microsphere is larger. However,the distribution of the diameter is not uniform. Pure t-ZrO2 phase can be obtained with the PVP addition increasing. When the addition of PVP is 10%,m-ZrO2 phase appears in the zirconia hollow microspheres. The lower electrospinning voltage results in the conglutination of hollow microspheres. The higher electrospinning voltage leads to forming zirconia particles. When the electrospinning voltage is 20 kV and the addition of PVP is 15%,high purity t-ZrO2 hollow microspheres are prepared. With the ratio of DMF to anhydrous ethanol reducing,the spherical degree of zirconia hollow microspheres gets better and their diameter becomes uniform. When the ratio of DMF to anhydrous ethanol is 0. 1,the thickness of the hollow wall is about 84 nm,and the outer diameter and inner diameter of zirconia hollow microspheres are 350 nm and 266 nm,respectively. The hollow structure is obvious.