Preparation of CO₂-adsorbable amine-functionalized polysilsesquioxanes containing cross-linked structures without using surfactants and strong acid or base catalysts

In this study, we prepared a series of amine-functionalized polysilsesquioxanes (PSQs) containing cross-linked structures via the hydrolytic condensation of mixtures of amino-group-containing organotrialkoxysilanes and bridged organoalkoxysilanes in water under CO₂ gas bubbling, followed by lyophilization and heat treatment at 120 °C for 4 h. Among the resulting materials, the amine-functionalized PSQ (PSQ-Am-CL-0.67) prepared from a mixture of 3-aminopropyltrimethoxysilane and bis[3-(trimethoxysilyl)propyl]amine (molar ratio 1:1) as the starting materials in CO₂-gas-bubbling water with a solution concentration of 0.67 mol/L exhibited relatively high CO₂ adsorption capacity under dry conditions (2.30 mmol(CO₂)/g(material)). Moreover, even after repeating the adsorption and desorption of CO₂ 10 times, the CO₂ adsorption capacity of PSQ-Am-CL-0.67 did not noticeably reduce, indicating that it could be used repeatedly as a CO₂ capture material. [Figure not available: see fulltext.].