Pentiptycene-Based Polyurethane with Enhanced Mechanical Properties and CO₂-Plasticization Resistance for Thin Film Gas Separation Membranes

Abstract

The development of thin film composite (TFC) membranes offers an opportunity to achieve the permeability/selectivity requirements for optimum CO separation performance. However, the durability and performance of thin film gas separation membranes are mostly challenged by weak mechanical properties and high CO plasticization. Here, we designed new polyurethane (PU) structures with bulky aromatic chain extenders that afford preferred mechanical properties for ultra-thin-film formation. An improvement of about 1500% in Young's modulus and 600% in hardness was observed for pentiptycene-based PUs compared to the typical PU membranes. Single (CO, H, CH, and N) and mixed (CO/N and CO/CH) gas permeability tests were performed on the PU membranes. The resulting TFC membranes showed a high CO permeance up to 1400 GPU (10 cm(STP) cm s cmHg) and the CO/N and CO/H selectivities of about 22 and 2.1, respectively. The enhanced mechanical properties of pentiptycene-based PUs result in high-performance thin membranes with the similar selectivity of the bulk polymer. The thin film membranes prepared from pentiptycene-based PUs also showed a twofold enhanced plasticization resistance compared to non-pentiptycene-containing PU membranes.

Improved gas transport properties of polyurethane–urea membranes through incorporating a cadmium‐based metal organic framework

“…The larger difference for the CO 2 /CH 4 gas mixture than for the CO 2 /N 2 mixture is due to the higher competition of CH 4 with CO 2 to pass through the membrane (CH 4 has a higher condensability than N 2 ). This behavior agrees well with results reported elsewhere …”

“…Rubbery polymers with ethereal polar groups are promising materials for CO 2 /N 2 separation. Recent studies reported that polyethylene (PU) glycol‐based polyurethanes are good candidates for use in gas separation membranes . The suppressing crystallization of ethereal groups in polyurethanes can be beneficial for the CO 2 selectivity improvements without a significant loss in the permeability …”

Influence of Blend Composition and Silica Nanoparticles on the Morphology and Gas Separation Performance of PU/PVA Blend Membranes

“…The type and strength of each hydrogen bonding can be identified by the magnitude and the shift of carbonyl bands. The first peak appearred at a lower frequency, ~1640 cm −1 , corresponded to the bonded carbonyl groups, and the peak at around 1720 cm −1 related to the free carbonyl groups [34,35].…”

Polyimides Containing Phosphaphenanthrene Skeleton: Gas-Transport Properties and Molecular Dynamics Simulations

“…The thermal degradation of the polymers is a very important parameter for membrane-based application. 40 Thermal performance of the polymers was assessed by thermogravimetric analysis (TGA) under synthetic air. The TGA images of the polymers are displayed in Figure 3.…”