Amine functionalized flat sheet porous polymer sorbents with oxidative degradation resistance for efficient low CO2 concentration capture applications

Amine-functionalized sorbents are highly effective for direct air capture (DAC) and point source capture (PSC) due to their ability to efficiently adsorb low concentration carbon dioxide (CO2). However, when these sorbents are exposed to heat, oxygen, and other atmospheric conditions, they can undergo oxidative degradation, decreasing the ability of these sorbents to adsorb CO2. Here, we study the degradation of an amidoxime modified polymer of intrinsic porosity (PIM-1-AO) that has been cast on a flat sheet and functionalized with either tris(3-aminopropyl)amine (TAPA) or tris(3-aminoethyl)amine (TAEA) yielding MC-PIM-1-AO-TAPA or MC-PIM-1-AO-TAEA, respectively. The sorbents were subjected to accelerated degradation under humid air at 75oC for up to five days. We demonstrated that MC-PIM-1-AO-TAPA not only exhibits superior resistance to degradation compared to MC-PIM-1-AO-TAEA but also outperforms any other amine functionalized sorbents aged under similar conditions suggesting that propyl chains add increased stability to the amine, compared to ethyl chains