Flat ultrafiltration PAN/BNE membranes with temperature-responsive performance obtained by modification with “smart” PVA copolymer

¹ Faculty of Technical Sciences, University “Prof. Dr. Assen Zlatarov”, 1 Prof. Y. Ykimov Bul., 8010 Burgas, Bulgaria
² Institute of Polymers, Bulgarian Academy of Sciences, Akad. G. Bonchev Str., Bl. 103-A, 1113 Sofia, Bulgaria

^* Corresponding author: mmiteva@uniburgas.bg

Abstract

The ultrafiltration (UF) composite polyacrylonitrile (PAN)/ butadiene–acrylonitrile elastomer (BNE) membrane obtained by the phase inversion method was modified with temperature sensitivity by physicochemical immobilization of hydrophobically modified poly(vinyl alcohol) (HMPVA). HMPVA was prepared by partial acetalization of poly(vinyl alcohol) (PVA) with a molar mass of 75000 g/mol, resulting in a temperature-sensitive copolymer with a phase transition temperature (T_tr) of 40.2^oC. Modification of the membranes was performed by introducing aqueous HMPVA solutions of different concentrations into the membrane structure, followed by its immobilization by cross-linking with glutaraldehyde. The composition, technological and structural characteristics of the membranes before and after the modification were investigated. Scanning electron microscopy (SEM) and barodynamic determinations were used in the typical UF operating pressure range (0–0.5 MPa), evaluating permeability (J, l/m².h) and rejection (R, %) of water and albumin as a calibrant (molecular mass ~76 kDa). Temperature-sensitive HMPVA in the membrane structure optimizes the energy and material efficiency of the membrane process, including membrane service life and maintenance.