Hollow fiber ultrafiltration membranes of poly(biphenyl-trifluoroacetone)

This paper reports a kind of fluorinated aromatic polymers for preparing high-performance hollow fiber ultrafiltration membranes. Poly(biphenyl-trifluoroacetone) (PBT) with all-carbon backbone and a high molecular weight is synthesized via a superacid-catalyzed Friedel-Crafts reaction between biphenyl and trifluoromethyl ketone, and applied to prepare hollow fiber membranes (HFMs) with a typical self-supporting structure. The concentrations of PBT and polyethylene glycol (PEG) in dope solutions are investigated in detail to reveal the HFMs' structure-performance relationship. The resulting PBT HFMs show an excellent scale-up, a membrane-forming ability and separation performance. Typically, the M-16/10 membrane has a BSA rejection up to 99.7% with a high pure water permeance of 353.3 L m−2 h−1 bar−1. Meanwhile, with strong mechanical properties these HFMs can operate at a high pressure of 4.0 bar. In addition, the permeance and the rejection almost do not change during a long-term filtration of a 500 ppm BSA solution, showing an excellent long-term stability of the HFMs. As a novel membrane material, the newly developed PBT should have a great potential in the preparation of separation membranes, particularly in the HFMs.