Polymers of intrinsic microporosity (PIMs) represent a novel class of glassy polymers that have attracted considerable attention in past years [1]. PIMs possess unique properties, combining outstanding permeability with moderate to high selectivity. Such properties make these polymers good candidates for a radical improvement compared to current state of the art gas separation membranes. The aim of this work is to analyse in detail the gas and vapor transport at 25°C in two polymers of intrinsic microporosity: PIM-EA-TB [2] and Amine-PIM-1 [3]. The pure vapor permeability was determined, using a differential permeameter with hydrogen as a carrier gas [4]. The gravimetric sorption method was used for the determination of pure gas and vapor sorption. The sorption kinetics and equilibrium sorption were determined with a calibrated quartz spiral balance and precise CCD camera [4]. As high free volume polymers, PIMs generally exhibit distinct physical aging due to a gradual collapse of their fractional free volume. Usually the process is faster at the first few weeks and then stabilizes or becomes notably mild. In our work, PIM aging was determined by permeation experiments carried out for a month with each membrane, using methanol vapours at constant activity (a=0.2 and a=0.6). A steep exponential decrease in both the diffusion and the permeability coefficient was observed in time. After approximately 4 weeks the transport characteristics of PIMs were stabilized at an almost constant value. The sorption experiments showed anomalous transport behaviour. In PIM-EA-TB, this behaviour could be described using a convection-diffusion model [5] with a concentration dependent convective term. In Amine-PIM-1 the analogy of a diffusion-reaction model was used [6]. In both cases, an excellent agreement between the experimental data and the models was found. Acknowledgements Part of the work leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. NMP3-SL-2009-228631, project DoubleNanoMem. The financial support of the Czech Science Foundation within the Grant Project 13-32829P is gratefully acknowledged. References 1. P.M. Budd, B.S. Ghanem, S.M. Makhseed, N.B. McKeown, K.J. Msayib, C.E. Tattershall, Chem. Commun., 2, 230 (2004). 2. M. Carta, R. Malpass-Evans, M. Croad, Y. Rogan, J.C. Jansen, P. Bernardo, F. Bazzarelli, N.B. McKeown, Science 339, 303 (2013). 3. C.R. Mason, L. Maynard-Atem, K.W.J. Heard, B. Satilmis, P.M. Budd, K. Friess, M. Lan?, P. Bernardo, G. Clarizia, J.C. Jansen, Macromolecules 47, 1021 (2014). 4. K. Friess, J.C. Jansen, O.Vopi?ka, A. Randová, V. Hynek, M. ?ípek, L. Bartovská, P. Izák, M. Dingemans, J. Dewulf, H.V. Langenhove, E. Drioli, J. Membr. Sci. 338, 161 (2009). 5. A.L. Pomerantsev, J. Appl. Polym. Sci. 96, 1102 (2005). 6. T. Yamaguchi, L.M. Boetje, C.A. Koval, R.D. Noble, C.N. Bowman, Ind. Eng. Chem. Res., 34, 4071 (1995).
Description of gas and vapor transport in polymers of intrinsic microporosity
Johannes C Jansen;
2014
Abstract
Polymers of intrinsic microporosity (PIMs) represent a novel class of glassy polymers that have attracted considerable attention in past years [1]. PIMs possess unique properties, combining outstanding permeability with moderate to high selectivity. Such properties make these polymers good candidates for a radical improvement compared to current state of the art gas separation membranes. The aim of this work is to analyse in detail the gas and vapor transport at 25°C in two polymers of intrinsic microporosity: PIM-EA-TB [2] and Amine-PIM-1 [3]. The pure vapor permeability was determined, using a differential permeameter with hydrogen as a carrier gas [4]. The gravimetric sorption method was used for the determination of pure gas and vapor sorption. The sorption kinetics and equilibrium sorption were determined with a calibrated quartz spiral balance and precise CCD camera [4]. As high free volume polymers, PIMs generally exhibit distinct physical aging due to a gradual collapse of their fractional free volume. Usually the process is faster at the first few weeks and then stabilizes or becomes notably mild. In our work, PIM aging was determined by permeation experiments carried out for a month with each membrane, using methanol vapours at constant activity (a=0.2 and a=0.6). A steep exponential decrease in both the diffusion and the permeability coefficient was observed in time. After approximately 4 weeks the transport characteristics of PIMs were stabilized at an almost constant value. The sorption experiments showed anomalous transport behaviour. In PIM-EA-TB, this behaviour could be described using a convection-diffusion model [5] with a concentration dependent convective term. In Amine-PIM-1 the analogy of a diffusion-reaction model was used [6]. In both cases, an excellent agreement between the experimental data and the models was found. Acknowledgements Part of the work leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. NMP3-SL-2009-228631, project DoubleNanoMem. The financial support of the Czech Science Foundation within the Grant Project 13-32829P is gratefully acknowledged. References 1. P.M. Budd, B.S. Ghanem, S.M. Makhseed, N.B. McKeown, K.J. Msayib, C.E. Tattershall, Chem. Commun., 2, 230 (2004). 2. M. Carta, R. Malpass-Evans, M. Croad, Y. Rogan, J.C. Jansen, P. Bernardo, F. Bazzarelli, N.B. McKeown, Science 339, 303 (2013). 3. C.R. Mason, L. Maynard-Atem, K.W.J. Heard, B. Satilmis, P.M. Budd, K. Friess, M. Lan?, P. Bernardo, G. Clarizia, J.C. Jansen, Macromolecules 47, 1021 (2014). 4. K. Friess, J.C. Jansen, O.Vopi?ka, A. Randová, V. Hynek, M. ?ípek, L. Bartovská, P. Izák, M. Dingemans, J. Dewulf, H.V. Langenhove, E. Drioli, J. Membr. Sci. 338, 161 (2009). 5. A.L. Pomerantsev, J. Appl. Polym. Sci. 96, 1102 (2005). 6. T. Yamaguchi, L.M. Boetje, C.A. Koval, R.D. Noble, C.N. Bowman, Ind. Eng. Chem. Res., 34, 4071 (1995).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
