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以异丙醇铝(AIP)为原料,采用溶胶-凝胶法,制备了纳米氧化铝(Al2O3)溶胶。研究了酸解剂、酸铝比[n(H+)/n(Al3+)]、陈化时间等因素对溶胶粒径和稳定性的影响,得到了制备稳定、透明纳米Al2O3溶胶的最佳工艺条件,即酸解剂HNO3;n(H+)/n(Al3+)=0.18~0.25;陈化时间20 h。为了改善聚偏氟乙烯(PVDF)膜的性能,通过PVDF与AIP的原位聚合,制备了不同PVDF含量的PVDF/Al2O3杂化膜。采用扫描电镜(SEM)、原子力显微镜(AFM)、红外光谱(FI-IR)、差示扫描量热法(DSC)、热失重分析(TGA)等手段对膜的结构和性能进行了表征。结果表明:杂化膜的纯水通量随着PVDF浓度的增大呈下降趋势,截留率则随着PVDF浓度的增大逐渐升高;AIP的加入使得杂化膜两相之间存在键合,可以增强Al2O3和PVDF之间的化学连接,从而提高杂化膜的亲水性和机械强度;添加AIP后,杂化膜的热分解温度向低温移动,即杂化膜的热稳定性下降;而AIP对PVDF膜的熔点影响不明显。
Aluminum isopropoxide (AIP) was used as raw material to prepare nano alumina (Al 2 O 3) sol by sol - gel method. The effects of acidolytic agent, ratio of n (H +) / n (Al3 +), aging time and other factors on the particle size and stability of the sol were investigated. The optimum conditions for the preparation of stable and transparent nanostructured Al2O3 sol were obtained. , That is acid hydrolysis agent HNO3; n (H +) / n (Al3 +) = 0.18 ~ 0.25; aging time 20 h. In order to improve the performance of polyvinylidene fluoride (PVDF) membranes, PVDF / Al2O3 hybrid membranes with different PVDF contents were prepared by in situ polymerization of PVDF and AIP. The structure and properties of the films were characterized by SEM, AFM, FI-IR, DSC and TG. The results showed that the pure water flux of hybrid membrane decreased with the increase of PVDF concentration, and the rejection increased with the increase of PVDF concentration. The addition of AIP resulted in the bonding between the two phases , Which can enhance the chemical connection between Al2O3 and PVDF to improve the hydrophilicity and mechanical strength of the hybrid membrane. After the addition of AIP, the thermal decomposition temperature of the hybrid membrane moves to low temperature, that is, the thermal stability of the hybrid membrane decreases. The AIP PVDF membrane melting point is not obvious.