It is well known that the sorption and transport properties of high free volume glassy polymers do vary significantly with time due to physical ageing that lowers the overall free volume and consequently gas permeability. In this work we perform a series of tests in which the ageing of polymeric membrane films based on a polymer of intrinsic microporosity (PIM-1) and TZ-PIM (PIM containing tetrazole unit) is induced with high temperature treatments under vacuum. The solubility and diffusivity values of CO2 and CH4 are measured at different pressures up to 32 atm and at 50°C within a pressure decay equipment on membranes 1) as cast; 2) thermally pre-treated at 120, 140 and 160°C. The effect of thermal treatment is more evident on the diffusivity than on the solubility coefficient, in both types of membranes. In particular the diffusivity of both gases decreases with increasing heat treatment temperature. Trends of diffusivity with concentration are also thoroughly inspected.
Aweke Elias Gemeda, Maria Grazia De Angelis, Michael D. Guiver, Giulio Cesare Sarti (2014). Effect of thermal treatment on the CO2 and CH4 sorption and diffusion in PIM-1 and TZ-PIM membranes.
Effect of thermal treatment on the CO2 and CH4 sorption and diffusion in PIM-1 and TZ-PIM membranes
GEMEDA, AWEKE ELIAS;DE ANGELIS, MARIA GRAZIA;SARTI, GIULIO CESARE
2014
Abstract
It is well known that the sorption and transport properties of high free volume glassy polymers do vary significantly with time due to physical ageing that lowers the overall free volume and consequently gas permeability. In this work we perform a series of tests in which the ageing of polymeric membrane films based on a polymer of intrinsic microporosity (PIM-1) and TZ-PIM (PIM containing tetrazole unit) is induced with high temperature treatments under vacuum. The solubility and diffusivity values of CO2 and CH4 are measured at different pressures up to 32 atm and at 50°C within a pressure decay equipment on membranes 1) as cast; 2) thermally pre-treated at 120, 140 and 160°C. The effect of thermal treatment is more evident on the diffusivity than on the solubility coefficient, in both types of membranes. In particular the diffusivity of both gases decreases with increasing heat treatment temperature. Trends of diffusivity with concentration are also thoroughly inspected.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
