[2.2]Paracyclophane-Based Polyimides of Intrinsic Microporosity for Gas Separation

Area of Science:

• Polymer Chemistry
• Materials Science
• Chemical Engineering

Background:

• Polyimides (PIs) are high-performance polymers known for thermal, mechanical, and chemical stability.
• Polymers of intrinsic microporosity (PIMs) offer permanent microporosity and structural robustness.
• Limited availability of complex dianhydrides hinders PIM development.

Purpose of the Study:

• To synthesize novel [2.2]-paracyclophane (PCP)-based polyimide PIMs.
• To investigate the effect of monomer structure and connectivity on gas separation properties.
• To explore PCP-derived dianhydrides for advanced PIM applications.

Main Methods:

• Synthesis of PCP-derived dianhydrides and amino-PCP monomers.
• Polymerization to form two families of PCP-polyimide PIMs.
• Gas sorption measurements (CO2/N2 separation).
• Characterization using solid-state NMR, FT-IR, WAXD, SEM, EDX, and TGA.

Main Results:

• Achieved very good CO2/N2 separation performance.
• Highest selectivity (∼40) observed for the meta-PCP-ethanoanthracene system (PCP-PI4).
• PCP-based polymers in pseudo-meta configuration showed CO2/N2 separation of 32.5.
• Demonstrated the crucial role of monomer design in tuning separation properties.

Conclusions:

• Successfully developed novel PCP-polyimide PIMs with tunable gas separation capabilities.
• Monomer design, particularly the meta-configuration, significantly enhances CO2/N2 selectivity.
• These materials show promise for advanced gas separation applications.