(419ap) Gas Permeability in PTMSP/Graphene, Pmtsp/Graphene Oxide Mixed Matrix Membranes

Poly(trimethyl silyl propine) (PTMSP) is a glassy polymer with high free volume and high gas permeability suitable for gas and vapor separation, that is also subject to physical aging which can drastically decrease the permeability with time.

We have studied the effect of addition of small amounts (below 1wt%) of graphene (G) and graphene oxide (GO) on He, N₂, CH₄ and CO₂ permeability in PTMSP. A specific analysis was carried out to compare the ageing of composite membranes with that of pure polymeric ones, within a time interval of 30 d. 

The addition of GO has an opposite effect with respect to the addition of graphene in PTMSP membranes on the permeability, and in particular it enhances the gas permeability while the presence of graphene lowers it. The effect of the gas kinetic diameter on the variation of gas permeability after filler addition was also quantitatively analyzed.

Both fillers have a significant impact on the ageing of PTMSP, i.e. they affect the variation of gas permeability with time. A high temperature treatment was performed on the composite membranes at 200°C, in order to study the possible reduction of graphene oxide and its effect on gas permeability.