(463e) Polyethylene Glycol Grafting of Ultrafiltration Cross-Linked Polyimide Membranes Via Plasma Modification to Fabricate Organic Solvent Nanofiltration (OSN) Membranes

A two-step process of organic solvents resistant nanofiltration membrane fabrication via high-density polyethylene glycol (PEG) plasma grafting on cross-linked polyimide (cPI) ultrafiltration (UF) substrate was developed in this work. An ultrathin PEG dense layer was successfully formed on cPI substrate surface that converted the UF membrane to a nanofiltration (NF) membrane by plasma treatment. In addition, the presence of PEG effectively prevents pore collapse of the UF support and maintained relatively high solvent permeance of substrate. Moreover, comparing to the cPI membrane, the PEG-modified membranes offer extremely high hydrophilicity resulting in the significant enhancement of isopropanol (IPA) permeance. The optimized PEG-grafted composite membrane shows a 99.64 % rejection of Rose Bengal (a molecular weight of 1017.64 g mol^-1) and a 5.91 L m^−2 h^−1 bar^−1 IPA permeance at 10 bar. The newly developed organic solvents nanofiltration (OSN) membranes also demonstrate good stability in alcohols over 400 hours. To our best knowledge, this is the first endeavor of utilizing PEG to directly develop OSN membranes by mean of plasma grafting. The study may not only widen the application of PEG grafting for OSN but also provide useful insights to design a green and cost-effective scale-up membranes fabrication process for industrial applications.