Optimization of polyethylene binder for heterogeneous ion exchange membrane manufacture to improve its mechanical stability

Abstract

ABSTRACTAim of this work is to propose polymer mixture for heterogeneous ion exchange membrane manufacture to improve membrane mechanical stability. Polyethylene (PE) binders [high‐density PE (HDPE), linear low‐density PE (LLDPE), metallocene‐linear low‐density PE (mLLDPE), and their mixtures in various ratios] with ion exchange resins were homogenized and extruded into membrane sheets. Processability of mixtures was considered using the data from extruder including torque and pressure before the extrusion die. Membrane samples were subjected to tensile deformation tests and tests of tear resistance and membrane electrochemical properties such as electrical resistance and permselectivity were measured. No significant variations in electrochemical properties of prepared membranes were observed, except of membrane made using pure mLLDPE as a binder. Surface resistance of this membrane was the highest (almost 8 Ω cm2) and as well the permselectivity (∼92%). The lowest surface resistance (lower than 3 Ω cm2) was determined for the membrane made using pure LLDPE as a binder. Therefore, taking into account the most important mechanical and processing characteristics, such as pressure before extrusion die, tensile strength, modulus of elasticity, and tear resistance assigning all these properties the same priority, membrane with the best combination of properties was prepared using the mixture of HDPE:LLDPE in the ratio of 80:20 as the binder. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46415.