Investigation of amino and amidino functionalized Polyhedral Oligomeric SilSesquioxanes (POSS®) nanoparticles in PVA-based hybrid membranes for CO2/N2 separation

Abstract Hybrid membranes were prepared using amino-functionalized Polyhedral Oligomeric SilSesquioxanes (POSS ® ) nanoparticles, with polyvinyl alcohol (PVA) and dip coated on Polyphenylene Oxide (PPO) as support. Different functionalities of amino and amidino POSS ® have been developed and evaluated for CO 2 /N 2 separation in order to understand the polymer/nanoparticle interaction and their impact on the CO 2 transport mechanism. CO 2 absorption and desorption studies were carried out to understand the chemical behavior of the CO 2 transport phenomena in solution. The as-obtained hybrid selective membrane materials were analyzed using various techniques, such as TGA, DSC, FT-IR, and XRD, while the gas permeation properties were evaluated in a CO 2 /N 2 mixture at room temperature. The membranes prepared with the amino- and amidino-functionalized particles show a CO2 permeability of 0.53 and 0.71 m 3 (STP)/m 2  bar h, respectively at a CO 2 /N 2 selectivity of around 40. Differences are explained through CO 2 absorption and desorption studies performed in solution showing a higher CO2 cyclic capacity for the amidino particles. However, when comparing these results with the bare PPO/PVA system, no clear advantageous effect of the addition of the nanoparticles was observed. Due to the interaction of the nanoparticles with the polymer matrix, the particles do not exhibit a carrier transport in the composite membranes. The addition of the amino and amidino POSS ® showed that the expected increase in CO 2 permeance is not reached due to the interaction of the nanoparticles with the polymer matrix. Moreover, the amino & amidino POSS ® do not exhibit a carrier transport in the composite membranes.