Hyper-Cross-Linked Polymers with Sulfur-Based Functionalities for the Prevention of Aging Effects in PIM-1 Mixed Matrix Membranes

Abstract

The instability of gas permeation rates over time in PIM-1-based membranes is one of the obstacles preventing the implementation of this technology on larger scales. The addition of porous materials to the PIM-1 matrix is a known process to reduce aging effects in PIM-1-based membranes. Many porous solids of various chemical natures have been tested, ranging from inorganic to inorganic–organic hybrids to completely organic materials. Here, we report on the synthesis of two hyper-cross-linked polymers (HCPs) based on the diphenyl sulfide monomer, synthesized in either dichloromethane at 35 °C or dichloroethane at 78 °C. Two mixed matrix membranes (MMMs) were obtained from the addition of 3 wt % of either filler to PIM-1. Both the CO2 permeation rates and the CO2/N2 selectivity were measured for the pure PIM-1 membrane and for the two MMMs over a period of 400 days. PIM-1 exhibits a classic aging behavior with an 85% drop in the CO2 permeation rate with respect to the initial value. For the two MMMs, a retention of 50% of the initial CO2 permeability was instead observed after more than 400 days of aging. Despite the low surface area and low pore volume of the fillers, we show that diphenyl sulfide-based HCPs can reduce the aging rate in PIM-1 membranes.

Impact of Sub-Ambient Temperature on Aging Rate and Gas Separation Properties of Polymers of Intrinsic Microporosity

“…However, its aging was much less pronounced, which could be inferred as resulting from its greater thickness slowing down film densification [ 28 ]. This indicates that the aging is only diffusivity (i.e., free volume) dependent, and, therefore, solubility should not be impacted by aging, which is consistent with observations from the literature [ 29 , 30 ]. This was verified by comparing the solubility of PIM-1_D obtained from both volumetric direct measurements and indirect calculation from permeation experiments.…”

Phenanthrene Derived Nanoporous Hypercrosslinked Polymeric Adsorbent for CO2 Capture from Flue Gas and Removal of Organic Dyes from Wastewater

“…Hou et al reported a CO 2 capture capacity and a CO 2 /N 2 selectivity of 3.3 mmol g –1 and 20.1, respectively, at 273 K using a carbonate-based HCP as the adsorbent . Begni and co-workers provided evidence regarding the function of PIMs in mitigating the aging effects of PIM-based mixed matrix membranes . Moreover, because of the presence of extensive π electrons, the HCPs are believed to adsorb aromatic organic molecules like organic dyes by π–π interaction.…”