The PEG-substituted solvents prepared in this work, TBP, and T i BP were tested for CO2 absorption at 25 and 40°C, using CO2 pressures from 0 to 20 bar on the Hiden microbalance. Plots of moles of CO2 dissolved per liter versus CO2 pressure are illustrated in Fig. , with the linear fit for the highest slope (T i BP at both temperatures) shown by a dashed line. Higher capacity for CO2 absorption is reflected in larger slopes for the linear fit for these plots. The slope and correlation coefficient for each solvent at both temperatures are listed in Table . These plots were all linear (r 2 ≥ 0.997) throughout the pressure ranges tested (0 to 10 bar). It was observed that CO2 was most soluble in T i BP at both temperatures. The CO2 solubility decreased slightly going from T i BP to TBP and decreased more significantly going from TBP to . The CO2 solubility continued decreasing as the PEG arm grew longer for ( ) and ( ), with CO2 absorption decreasing by as much as 10% for (3) at both temperatures. We have observed similar CO2 absorption results when varying the PEG arm lengths in hybrid PEG/siloxane CO2 solvents, where shorter PEG substituents tended to have higher CO2 absorption. But unlike those hybrid solvents, the inclusion of etheric groups failed to improve CO2 uptake.