The Preparation Of N Doped PVDF/TiO₂ Composite Membrane By Electrospinning And Their Performance

In this paper, the process of PVDF electrospinning was researched The electrospinng solution, solvent ratio and the spinning voltage were studied, and these factors are the basic parameter of electrospinning process. The results showed that the best ratio of DMAc and acetone solvent was 3:7, the best concentration of PVDF was 10%, the proprioate voltage was 20 kV.This paper studied the combination of sol-gel process and electrospinning method for preparing PVDF/TiO2 membrane, and the properties of PVDF/TiO2 and N- PVDF/TiO2. membrane material. TiO2 sol gel method, was combined with the electrospinning method, The PVDF/TiO2 prepared by sol-gel method and electrospinning method have high porosities and good mechanical properties. The SEM give us information that the composite membrane prepared by this method shows an average size of 300 nm diameter. The fibers appears smooth, continuous, and no drops.The FTIR and XRD provide theoretical basis of the introduction of TiO2, it weakened the PVDF crystal structure of α, and undermines the crystalline regularity, meanwhile improves the mechanical properties and hydrophilic absorbent properties. The degradation of methyl orange showed that with increasing TiO2 content, the composite membrane degradation rate of methyl orange improved. When the TiO2 content was 8%, the photocatalytic degradation rate was 49.7%. The results showed that the introduction of TIO2 could improve the catalytic properties of the composite membranes.Finally, the Nitrogen doped membrane was prepared by combining electrospinning process and sol-gel method. The N-doped membrane showed higher porosities compared with non-doped membrane. The SEM showed that the higher N doping content, the smaller diameter.When the content of N increases to 5%, the fibers exhibited uneven thickness.The FTIR and XRD showed that, with the increasing of the N content, PVDF exhibited α polymorph weakened. The TG curve showed that N-doped membrane weight loss temperature was higher than undoped PVDF/TiO2, which indicated that N doping could improve thermal properties. In methyl orange degradation tests, the degradation rate of N- PVDF/TiO2 membrane of methyl orange was higher than non-doped membrane, and the highest degration rate was three times than non-doped PVDF/TiO2 membrane under the same conditions. Therefore, N doping was a good method to improve the photocatalytic properties.