Investigation of density, viscosity and derived thermodynamic properties of CO2-free and CO2-loaded poly(ethylene imine) aqueous systems at different temperatures and 0.1 MPa

Abstract

In this work, the density and viscosity for poly(ethylene imine) (PEI1800/10000) aqueous systems with and without CO2 over PEI concentrations (wt% = 5, 10, 15, 20, 30) are measured at temperatures from (293.15 to 333.15) K and 0.1 MPa. Based on the experimental data, the thermal expansion coefficient (αp), viscosity activation energy (Eη) and CO2 diffusion coefficient (DCO2) are calculated. The results show that the density and viscosity increase as the PEI concentration and CO2 loading increase. The higher molecular weight samples also give higher density and viscosity. The high viscosity further results in the large activation energy and low CO2 diffusion coefficient. All the experimental results are discussed from the perspective of intermolecular interactions which are further verified by the reaction mechanism and FT-IR spectra.