In the last decade PIMs have been recognized as potential candidates for the development of highly permeable and selective gas separation membranes. The archetypal PIM-1 [1], owes its microporosity and high gas permeability to a rigid contorted backbone structure [2] with dibenzodioxan and spirobisindane units. Meanwhile, functional groups like thioamide [3] and carboxylic acid [4] have been introduced into the PIM-1 structure to tailor permeability and/or selectivity for specific needs. Various other structures have been reported based for instance on polyimide backbone chemistry (PIM-PI [5]). In the present paper we will discuss the work on novel PIMs synthesized by Tröger's base formation (TB-PIM, Fig. 1). Figure 1. The structure of ethanoanthracene based TB-PIM. The rigid contorted backbone structure of these polymers of intrinsic microporosity, prevents efficient chain packing and brings them, even more than traditional glassy polymers, into a thermodynamic non-equilibrium state. One of the common features for nearly all such high free volume polymers is that there is usually a strong spread in the transport properties between different samples of one and the same polymer type. This is because their properties depend on the sample history. Sample history can be made more uniform by alcohol soaking of the PIMs, thus removing residual solvent and increasing microporosity [1]. A side-effect is that the transport properties may become strongly time-dependent after this treatment. Another complication is that these polymers seem to be also rather sensitive to the specific technique used for the gas permeation measurements and for the measurement protocol. This is the reason why many different results can be found in the literature. In this paper we will discuss in detail the transport properties of TB-PIM, and other novel members of the PIM family. In particular we will focus on the difference between pure gas and mixed gas permeation, on the difference between a fixed volume pressure increase setup and a constant pressure variable volume setup with mass spectrometric analysis, on the effect of feed pressure and other experimental variables. The basic transport parameters, permeability, diffusivity and solubility will be determined by time lag analysis and compared to those of direct sorption analysis. Finally, experimental data will be also confronted with results from structural and molecular dynamics simulation studies. Acknowledgements The work leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° NMP3-SL-2009-228631, project DoubleNanoMem. References 1.P.M. Budd, N.B. McKeown, B.S. Ghanem, K.J. Msayib, D. Fritsch, L. Starannikova, N. Belov, O. Sanfirova, Y.P. Yampol'skii, V. Shantarovich, Gas permeation parameters and other physicochemical properties of a polymer of intrinsic microporosity: Polybenzodioxane PIM-1, J. Membr. Sci. 2008, 235, 851-860. 2.N.B. McKeown and P.M. Budd, Exploitation of intrinsic microporosity in polymer-based materials, Macromolecules 2010, 43, 5163-5176. 3.C.R. Mason, L. Maynard-Atem, N.M. Al-Harbi, P.M. Budd, P. Bernardo, F. Bazzarelli G. Clarizia, J.C. Jansen, Polymer of Intrinsic Microporosity Incorporating Thioamide Functionality: Preparation and Gas Transport Properties, Macromolecules, 2011, 44, 6471-6479. 4.Du, N.; Robertson, G. P.; Song, J.; Pinnau, I.; Guiver, M. D., High-performance carboxylated polymers of intrinsic microporosity (PIMs) with tunable gas transport properties, Macromolecules 2009, 42, 6038-6043. 5.Ghanem, B.S., McKeown, N.B., Budd, P.M., Al-Harbi, N.M., Fritsch, D., Heinrich, K., Starannikova, L., Tokarev, A., Yampolskii, Y., Synthesis, characterization, and gas permeation properties of a novel group of polymers with intrinsic microporosity: PIM-polyimides, Macromolecules, 2009, 42, 7881-7888.
Analysis of gas and vapour transport in novel polymers of intrinsic microporosity (PIMs)
Paola Bernardo;Fabio Bazzarelli;Gabriele Clarizia;Franco Tasselli;Elena Tocci;
2012
Abstract
In the last decade PIMs have been recognized as potential candidates for the development of highly permeable and selective gas separation membranes. The archetypal PIM-1 [1], owes its microporosity and high gas permeability to a rigid contorted backbone structure [2] with dibenzodioxan and spirobisindane units. Meanwhile, functional groups like thioamide [3] and carboxylic acid [4] have been introduced into the PIM-1 structure to tailor permeability and/or selectivity for specific needs. Various other structures have been reported based for instance on polyimide backbone chemistry (PIM-PI [5]). In the present paper we will discuss the work on novel PIMs synthesized by Tröger's base formation (TB-PIM, Fig. 1). Figure 1. The structure of ethanoanthracene based TB-PIM. The rigid contorted backbone structure of these polymers of intrinsic microporosity, prevents efficient chain packing and brings them, even more than traditional glassy polymers, into a thermodynamic non-equilibrium state. One of the common features for nearly all such high free volume polymers is that there is usually a strong spread in the transport properties between different samples of one and the same polymer type. This is because their properties depend on the sample history. Sample history can be made more uniform by alcohol soaking of the PIMs, thus removing residual solvent and increasing microporosity [1]. A side-effect is that the transport properties may become strongly time-dependent after this treatment. Another complication is that these polymers seem to be also rather sensitive to the specific technique used for the gas permeation measurements and for the measurement protocol. This is the reason why many different results can be found in the literature. In this paper we will discuss in detail the transport properties of TB-PIM, and other novel members of the PIM family. In particular we will focus on the difference between pure gas and mixed gas permeation, on the difference between a fixed volume pressure increase setup and a constant pressure variable volume setup with mass spectrometric analysis, on the effect of feed pressure and other experimental variables. The basic transport parameters, permeability, diffusivity and solubility will be determined by time lag analysis and compared to those of direct sorption analysis. Finally, experimental data will be also confronted with results from structural and molecular dynamics simulation studies. Acknowledgements The work leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° NMP3-SL-2009-228631, project DoubleNanoMem. References 1.P.M. Budd, N.B. McKeown, B.S. Ghanem, K.J. Msayib, D. Fritsch, L. Starannikova, N. Belov, O. Sanfirova, Y.P. Yampol'skii, V. Shantarovich, Gas permeation parameters and other physicochemical properties of a polymer of intrinsic microporosity: Polybenzodioxane PIM-1, J. Membr. Sci. 2008, 235, 851-860. 2.N.B. McKeown and P.M. Budd, Exploitation of intrinsic microporosity in polymer-based materials, Macromolecules 2010, 43, 5163-5176. 3.C.R. Mason, L. Maynard-Atem, N.M. Al-Harbi, P.M. Budd, P. Bernardo, F. Bazzarelli G. Clarizia, J.C. Jansen, Polymer of Intrinsic Microporosity Incorporating Thioamide Functionality: Preparation and Gas Transport Properties, Macromolecules, 2011, 44, 6471-6479. 4.Du, N.; Robertson, G. P.; Song, J.; Pinnau, I.; Guiver, M. D., High-performance carboxylated polymers of intrinsic microporosity (PIMs) with tunable gas transport properties, Macromolecules 2009, 42, 6038-6043. 5.Ghanem, B.S., McKeown, N.B., Budd, P.M., Al-Harbi, N.M., Fritsch, D., Heinrich, K., Starannikova, L., Tokarev, A., Yampolskii, Y., Synthesis, characterization, and gas permeation properties of a novel group of polymers with intrinsic microporosity: PIM-polyimides, Macromolecules, 2009, 42, 7881-7888.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
