Cross-linked copolymer, method for preparing the same, and gas separation membrane comprising the same

High-Permeability and High-Selectivity CO2 Separation Membrane Material Based on Norbornene-Based Cross-Linked Structure

This technology features a cross-linked copolymer obtained by mixing two types of norbornene-based macromonomers synthesized with different cross-linking agents, as well as a gas separation membrane containing it. It incorporates both CO2-soluble and permeable units into a single polymer to form a chemical cross-linked structure.

Polymer membranes have historically struggled to improve permeability and selectivity simultaneously due to the trade-off between the two, and commercial materials like cellulose acetate or polyimide have failed to meet the economic standards for flue gas CO2 separation. Glassy polymer membranes suffer from performance degradation due to physical aging and plasticization under high pressure, while existing norbornene-based membranes have been limited by low permeability and selectivity.

This technology utilizes a cross-linked network connected via ring-opening metathesis polymerization to achieve a CO2 permeability of over 380 Barrer and a CO2/N2 selectivity of over 50, while ensuring resistance to aging, plasticization, and thermal instability. It can be applied to membrane module materials for carbon capture in power plants and steel mills, natural gas purification, and biogas upgrading, contributing to the construction of low-energy CO2 separation facilities with minimal performance degradation during long-term operation.

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Key Features:

• A cross-linked copolymer of Formula 1, in which compound X of Formula 2 and compound Y of Formula 3 are combined such that the sum of their mole fractions is 1
• A cross-linked copolymer containing X and Y in a molar ratio of 6:1 to 12:1, with molecular weights of 900–2900 g/mol and 1500–3500 g/mol, respectively
• A gas separation membrane for CO2 separation exhibiting a CO2 permeability of 380 Barrer or higher and a CO2/N2 selectivity of 50 or higher at 1 bar and 30°C
• A step of preparing a cross-linked copolymer by mixing macromonomers, each formed by reacting a first and second norbornene-based monomer with a cross-linking agent in a 1:1 to 1:5 molar ratio, in the presence of a second-generation Grubbs catalyst

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This invention was developed with support from the Ministry of Education for the development of blue carbon biomass-based source materials and the establishment of a marine resource recycling platform.

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