Enhancement of performance and stability of thin-film nanocomposite membranes for organic solvent nanofiltration using hypercrosslinked polymer additives

Abstract

Hypercrosslinked polymer (HCP) additives were successfully incorporated into two polymer matrices: glassy polymer with intrinsic microporosity comprising ethanoanthracene and Tröger's base (PIM-EA-TB) as well as rubbery polydimethylsiloxane (PDMS), forming thin-film nanocomposite (TFN) membranes for organic solvent nanofiltration (OSN) applications. The thermal stability and surface morphology of TFN membranes were characterized by TGA and SEM. OSN results showed that HCP additives increased the alcohol permeances for both kinds of membranes as it provided extra pathways for alcohol molecules to transport through the membranes. Particularly, the PIM-EA-TB membrane gained above 32% improvement on methanol and ethanol permeances after loading of 5 wt% HCP, whilst maintaining a rejection of 92% for Rose Bengal. Moreover, the physical aging of PIM-EA-TB membrane was retarded by HCP additives and the swelling of the PDMS membrane in non-polar solvents was reduced. In small quantities, the HCP nanoparticles proved to be effective additives to improve the OSN performances for both glassy and rubbery polymer membranes. • Hypercrosslinked polymers (HCPs) were incorporated into glassy and rubbery polymer matrices. • HCPs enhanced the separation performances of polymer membranes during organic solvent nanofiltration. • HCPs mitigated physical aging in glassy polymers and swelling of rubbery polymers. • Interaction mechanisms between HCPs and polymer chains at the interface were proposed.