Preparation of polyester amide nanofiltration membrane by low concentration hydroxyl monomer induced piperazine through intermolecular interaction

In the preparation of polyester amide nanofiltration membranes, the utilization of excessively high concentrations of monomer containing polyhydroxyl group and prolonged reaction time may seriously reduce the production efficiency. Based on the polarity characteristics of monomers containing both hydroxyl and amino groups, this study proposed a new method through dipole-dipole interactions between polar molecules to form a stable “transition state” with a low concentration (0.004 % w·v⁻¹) of piperazine monomer and the highly polar monomer N-(2-Hydroxyethyl)ethylenediamine, for facilitating the rapid synthesis of polyester amide nanofiltration membranes. This synergistic mechanism significantly accelerated the reaction rate with trimesoyl chloride and effectively improved the efficiency of preparation of polyester amide composite nanofiltration membranes. The dynamic changes of the reaction under this mechanism were thoroughly analyzed through physicochemical characterization, molecular dynamics simulation, density functional theory calculations, and performance testing. This research provided a new theoretical basis for the preparation of polyester amide nanofiltration membranes with low concentrations of hydroxyl monomers and promoted the development of polyester-amide nanofiltration membranes with low energy consumption and high efficiency.