Preparation And Characterization Of Partially Degradable Hollow Fiber Membranes Based On Polysulfone/Poly(L-Lactide-Co-Glycolide-Co-Epsilon-Caprolactone) Blends

The method of preparation of partly degradable asymmetric hollow fiber membranes based on polysulfone/poly(L-lactide-co-glycolide-co-epsilon-caprolactone) blends (PSf/LGC) is presented. The membrane-forming blends were prepared by mixing two solutions: PSf in N-methyl-2-pyrrolidone and LGC in tetrahydrofuran. Further, PSf/LGC membranes were obtained by a dry/wet-spinning phase-inversion technique and treated with a sodium hydroxide solution using the flowing method. The membrane properties such as hydraulic permeability coefficient (UFC), retention coefficients, and structure morphology were evaluated before and after hydrolysis. An increase in the ultrafiltration coefficient was observed, while the retention coefficient did not change significantly in the case of membranes after post-treatment. The hydrolysis of LGC component in the terpolymer was evaluated by the weight method. Measurements of membrane weight loss before and after the hydrolysis process confirmed the removal of more than 50 wt.% of the LGC component from investigated membranes, resulting in permeability increase due to increased membrane porosity. Fourier transform infrared spectroscopy (FTIR) analysis also confirms significant LGC polymer removal. Furthermore, a computer-aided image processing method was used for investigating the morphology before and after the hydrolysis process. This method verified the changes in membranes' morphology by the differences of membranes' porosity. The total porosity of membranes increased from 34% to 38% to 42% after the hydrolysis process.