Synthesis and gas transport properties of UV-cured low-viscosity fluorine-containing telechelic polyimide membranes

• Published in: Desalination and water treatment Vol. 51; no. 25-27; pp. 5138 - 5148
• Main Authors: Shindo, Ryohei, Yokouchi, Akira, Shirokura, Hayato, Yoshida, Kazuhito, Miyata, Sou, Sato, Shuichi, Kanehashi, Shinji, Nagai, Kazukiyo
• Format: Journal Article Conference Proceeding
• Language: English
• Published: L'Aquila Elsevier Inc 01-07-2013; Desalination Publications
• Subjects: Anhydrides; Applied sciences; CO2; Cross-linked; Crosslinking; Density; Exact sciences and technology; Exchange resins and membranes; Forms of application and semi-finished materials; Gas separation; Irradiation; Low-viscosity; Membrane; Membranes; Polyimide; Polyimide resins; Polymer industry, paints, wood; Selectivity; Technology of polymers; Ultraviolet; Polyimide; UV; Gas separation; Cross-linked; Low-viscosity; CO2; Membrane; Viscosity; Transport properties; Photochemical crosslinking; Molecular structure; Fluorine containing polymer; Telechelic polymer; Aromatic polymer; Condensation polymerization; Experimental study; CO; Thermal stability; Thermal properties; Gas permeability; Ultraviolet radiation; Preparation; Crosslinked polymer; Rheological properties
• ISSN: 1944-3986; 1944-3994; 1944-3986
• DOI: 10.1080/19443994.2013.768407

A novel ultraviolet (UV) cross-linking method using fluorine-containing telechelic polyimide membranes was investigated. The base fluorine-containing polyimide was synthesized by polycondensation using the monomers, 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 2,3,5,6-tetramethyl-1,4-phenylene diamine (TeMPD). Both chain ends of the 6FDA-TeMPD polyimide were end-capped with either UV-reacted groups, 1,1-bis(acryloyloxy methyl) ethyl isocyanate (BEI) group or p-aminostyrene (PAS) group. The two types of telechelic polyimide membranes, 6FDA-TeMPD-BEI and 6FDA-TeMPD-PAS, were formed with UV irradiation from the low-viscosity solutions using the solvent-casting method. The base polyimide membrane was soluble in tetrahydrofuran, whereas both UV-cured telechelic polyimide membranes were partly insoluble in it. This result suggested that both telechelic polyimides reacted at the polymer chain ends through UV irradiation. The density values of the UV-cured membranes were almost the same. Thus, this cross-linking method could prevent significant membrane densification compared with other conventional cross-linking methods. As the UV irradiation time increased, the gas selectivity in both UV-cured polyimide membranes increased without a significant decrease in gas permeability. The increase in ideal gas selectivity was attributed to the increase in the gas diffusivity selectivity rather than the solubility selectivity.