"Partition Method"-Inspired Fabrication of Hierarchically Porous Polyetherimide via Supercritical CO2 Foaming: Achieving Efficient Adsorption of Carbon Dioxide

Although supercritical carbon dioxide foaming technology has achieved significant advances in the fabrication of porous polymers, the slow adsorption of carbon dioxide and the high melt strength of engineering plastics make it difficult to foam. Herein, the "partition method" is used to divide block polyetherimide (PEI) into many tiny parts through the interconnected pores to realize the rapid adsorption of CO2 molecules. Specifically, an adsorption capacity of 9.18 wt % for porous PEI was obtained at 35 degrees C for just 1 h which was considerably higher than that of 4.36 wt % for non-porous PEI. Then, PEI with a uniform and ordered hierarchically porous structure (micro-and nanoscale) was successfully prepared by external force-induced cell nucleation growth. Meanwhile, this treatment has little effect on the thermal properties of the polymer. This green strategy applies to other general plastics, for example, polystyrene, and paves the way for designing large-scale hierarchically porous components such as porous bearing cages, tissue engineering scaffolds, and thermal insulation foam.