Mesoporous phenolic/carbon materials templated by CO₂-based PEO-b-PCHC diblock copolymers through mediated competitive intermolecular hydrogen bonding interactions for CO₂ capture

The CO2-based diblock copolymer, poly(ethylene oxide-b-cyclohexene carbonate) (PEO-b-PCHC), was synthesized via ring opening copolymerization (ROCOP) by using PEO as a macro-chain-transfer agent. Theses diblock copolymers were comprehensive characterized by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) to gain insights into their chemical structures and thermal properties. The microphase separation was induced after blending with phenolic resin through medicated by competitive hydrogen bonding interaction between phenolic hydroxyl (OH) group with ether unit of PEO and CO unit of PCHC based on FTIR analyses. Small angle X-ray scattering (SAXS) analyses also provided the self-assembled structures of specific phenolic/PEO-b-PCHC blends following thermal polymerization at 180 degrees C because of the reaction-induced microphase separation mechanism. Upon removal of PEO-b-PCHC diblock copolymer templates at 350 degrees C, mesoporous phenolic resins including cylindrical, spherical and worm-like structures were obtained based on SAXS, transmission electron microscope (TEM) and nitrogen adsorption/desorption analyses. Furthermore, the mesoporous carbons were further obtained from mesoporous phenolic resin thermal calcined at 700 degrees C under N-2 atmosphere. These carbonized mesoporous materials exhibited impressive characteristics such as high surface areas and they demonstrated effective CO2 capture capabilities (4.5 mmol g(-1) at 273 K). The captured CO2 could subsequently be employed in ROCOP again for synthesizing CO2-based copolymers, aligning with the principles of a circular economy.