Highly Permeable Benzotriptycene-Based Polymer of Intrinsic Microporosity

Area of Science:

• Materials Science
• Polymer Chemistry
• Chemical Engineering

Background:

• Polymers of intrinsic microporosity (PIMs) are crucial for gas separation membranes due to their high free volume.
• Developing PIMs that balance high permeability with selectivity remains a significant challenge in membrane technology.

Purpose of the Study:

• To synthesize and characterize a novel PIM derived from a diaminobenzotriptycene monomer.
• To evaluate the gas transport properties and aging behavior of the new PIM for potential membrane applications.

Main Methods:

• Synthesis of a novel polymer of intrinsic microporosity (PIM-BTrip-TB) via Tröger's base formation.
• Characterization of the polymer's properties including BET surface area, solubility, molecular mass, and film-forming ability.
• Gas permeability and selectivity measurements for various gas pairs (H2/N2, O2/N2, H2/CH4, CO2/CH4) before and after aging.

Main Results:

• The synthesized PIM-BTrip-TB exhibits a high BET surface area (870 m2 g-1) and good processability.
• The polymer demonstrates high permeability (e.g., P_H2 = 9980 Barrer) and moderate selectivity, surpassing 2008 Robeson upper bounds for several gas pairs.
• Aging of the polymer leads to decreased permeability but significantly enhanced selectivities, indicating improved separation performance over time.

Conclusions:

• The novel PIM-BTrip-TB shows promising performance for gas separation membranes, exceeding established benchmarks.
• The observed aging behavior, with increased selectivity, suggests potential for long-term operational stability and efficiency in gas separation processes.