Effect of Graphene and Graphene Oxide Nanoplatelets on the Gas Permselectivity and Aging Behavior of Poly(trimethylsilyl propyne) (PTMSP)

Abstract

Membranes obtained by adding small amounts (1 wt %) of nanoplatelets of graphene (G) and graphene oxide (GO) to poly­(1-trimethylsilyl-1-propyne) (PTMSP) were fabricated with a simple route, and their gas permeability was measured at 30 °C over 9 months. In most cases, variations of PTMSP permeability due to the addition of filler are limited, while the ideal selectivity of CO2/He, CH4/He, and CH4/N2 is slightly enhanced by addition of filler. Specific measurements indicate that the CO2 and CH4 diffusivity are more strongly affected by addition of graphene than their solubility: such behavior indicates that the filler modifies mainly the microstructure of the polymer rather than its interactions with the gas, as it is reasonable. The most significant quantitative effect observed after filler incorporation is the reduction of PTMSP aging, that was monitored by studying gas permeability after 9 months of aging at room temperature and after annealing at 200 °C. The reduction of aging observed after adding graphene is more significant than that obtained with large amounts (up to 20 vol %) of other inorganic fillers, like MgO and TiO2, even though the amount of filler added in this work is small (<1 wt %). Such behavior, coupled to the generally favorable effect of filler on gas permeability and selectivity, makes such materials extremely promising for real applications.

Effective gas separation through graphene oxide containing mixed matrix membranes

“…This observation was also relevant to the disruption of polymeric chains caused by GO filler. In addition to this improvement, the other positive effect of GO was postponing the PTMSP ageing …”

“…Since GO sheets possess high aspect ratio, decrease in gas permeability is anticipated when added as a filler to a membrane. Although it is a logical trend for GO containing membranes, it is not the same for all kinds of membranes . Thus, each polymer/GO combination should be studied in detail in terms of gas separation behavior.…”

“…However PVDF was extensively investigated as membrane in other areas of membrane processes . Considering some published papers on GO containing MMMs, it can be concluded that GO with high aspect ratio is an inspiring filler for efficient MMM construction in practical gas separation application. PVDF was chemically modified using mixture of KOH and KMnO 4 according to the previous study .…”

Effects of aging on poly(1‐trimethylsilyl‐1‐propyne) membranes irradiated with vacuum ultraviolet radiation for gas separation

“…This phenomenon should be solved because the membrane gas permeability continuously decreases. Researchers have recently synthesized membranes that can prevent aging . VUV surface modification forms functional groups on the surface.…”

“…Researchers have recently synthesized membranes that can prevent aging. [17][18][19] VUV surface modification forms functional groups on the surface. These functional groups have a high surface free energy and exhibit a physical aging effect.…”