Abstract
The co-extrusion of solvent at the outer layer of a dope solution in a thermally induced phase separation (TIPS) process has led to significant improvements in membrane characteristics, especially pure water permeability stability. This work investigates the effects of the poly (vinylidene fluoride) (PVDF) molecular weight and concentration on the characteristics of hollow fiber membranes prepared using this method. The PVDF molecular weight had little effect on the phase diagram of the PVDF/diphenyl carbonate (DPC) system, and effectively controlled the penetration depth and quantity of the extruded solvent (propylene carbonate (PC)) inside the polymer dope solution as well as the overall performance of the hollow fiber membranes. When the PVDF concentration was low, the PVDF molecular weight was crucial in controlling the penetration of the extruded solvent. For a PVDF/DPC system that led to the mainly bicontinuous structure which resulted from L-L phase separation, the penetration of the PC inside the membrane considerably changed the surface and sublayer structure from a bicontinuous structure with spherulite to a composite spherulite embedded in the bicontinuous structure and isolated spherulite structure. To obtain an appropriate membrane with considerable water permeability stability, it is necessary to choose an appropriate polymer molecular weight and concentration.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
