Crystallization Behavior Of Blend PVDF And Preparation Of Anti-fouling Ultrafiltration Membrane

PVDF, as a kind of crystallographic polymer, has favorable chemical stability, thermostability and mechanical stability. However, the application of PVDF in water separation system is limited by the strong hydrophobicity. In the purpose of expanding the application of that material, through blending, immerged phase-inversion method was used to prepare two kinds of ternary blends membrane (PVDF/PSF/PMMA) respectively, which improve the hydrophily and pollution-resistant of PVDF.The compatibility of that ternary system (PVDF/PS/PMMA) was observed by solubility parameter method and microscope before blend membrane was prepared. The experimental results show that the blend system of PVDF/PS/PMMA is semimiscible.The percentage of blending, casting solution temperature, coagulating bath temperature, etc, was studied in the purpose of investigating the relationship between experiment condition and crystalline behavior of PVDF/PSF/PMMA. Ideal PVDF crystalline form was obtained by regulate and control system compatibility and crystallization rate. The separation performance and the pollution-resistant of the membrane is the best, when the blending ratio of the PVDF:PSF:PMMA was 8:1:1, casting membrane liquid temperature was 90℃and LiC1/PEG200 was acted as mixing additives.