Membranes intrinsic microporosity

Budd PM, Msayib KJ, Tattershall CE, Ghanem BS, Reynolds KJ, McKeown NB, Fritsch D. Gas separation membranes from polymers of intrinsic microporosity. J Membr Sci 2005 251(l-2) 263-269. 

To surpass Robeson s upper bound, materials are emerging that rely on transport mechanisms other than solution-diffusion through glassy or rubbery polymeric materials. In particular, a number of materials have been developed that possess fixed microporosity (2 nm or less) in contrast to the activated, transient molecular gaps that give rise to diffusion in most polymers. These materials include amorphous and crystalline (zeolite) ceramics [68-69], molecular sieve carbons [70], polymers that possess intrinsic microporosity [71-72], and carbon nanotube membranes [73-76]. Transport in such materials is determined primarily by the average size and size distribution of the microporosity - the porosity can be tuned to allow discrimination between species that differ by less than one Angstrom in size. However, surface... 

N.B. McKeown and P.M. Budd, Polymers of intrinsic microporosity (PIMs) organic materials for membrane separations, heterogeneous catalysis and hydrogen storage, Chem. Soc. Rev., 35 (2006) 675-683. 

The inventors caU this polymer class polymers of intrinsic microporosity (PIMs) , because their porosity arises as a consequence of the molecular structure and is not generated solely through processing. The PIMs can exhibit analogous behavior to that of conventional materials, but, in addition, may be processed into convenient forms for use as membranes [291]. The gas-permeation properties of membranes formed from PIM-1 were investigated at the GKSS... 

Advanced organic and inorganic membranes and materials include polymers of intrinsic microporosity (PIMs), microporous PVDF, perovskite and palladium alloy membranes [45]. PIM membranes have displayed both high permeability with high selectivity for various gas mixtures. Major commercial and promising applications of membrane GS are delineated below [43—45] ... 

Ahn J, Chung W-J, Pinnau 1 et al (2010) Gas transport behavior of mixed-matrix membranes composed of silica nanoparticles in a polymer of intrinsic microporosity (PlM-1). J Membr Sci 346 280-287... 

Li FY, Xiao Y, Chung T-S et al (2012) High-performance thermally self-cross-linked polymer of intrinsic microporosity (PIM-1) membranes for energy development. Macromolecules 45 1427-1437... 

P. M. Budd, E. S. Elabas, B. S. Ghanem, S. Makhseed, N. B. McKeown, K. J. Msayib, C. E. TattershaU, D. Wang, Solution-processed, organophiUc membrane derived from a polymer of intrinsic microporosity, Adv. Mater, 16, 456-459 (2004). 

A.R Bushell, M.P. Attfleld, C.R. Mason, P.M. Budd, Y. Yampolskii, L. Starannikova, A. Rebrov, F. Bazzarelli, P. Bernardo, J. Carolus Jansen, M. Lane, K. Fiiess, V. Shantarovich, V. Gustov, V. Isaeva, Gas permeation parameters of mixed matrix membranes based on the polymer of intrinsic microporosity PIM-1 and the zeoMc imidazolate framework ZIF-8, Journal of Membrane Science 427 (2013) 48-62. 

M.M. Khan, V. Fihz, G. Bengtson, S. Shishatskiy, M.M. Rahman, J. LiUepaerg, V. Abetz, Enhanced gas permeability by fabricating mixed matrix membranes of functionalized multiwalled carbon nanotubes and polymers of intrinsic microporosity (PIM), Journal of Membrane Science 436 (2013) 109-120. 

R. Swaidan, X. Ma, E. Litwiller, I. Pinnau, High pressure pure and mixed-gas separation of CO2/CH4 by thermally-rearranged and carbon molecular sieve membranes derived from a polyimide of intrinsic microporosity, J. Membr. Sci. 447 (2013) 387-394. 

In polymeric mixed matrix membrane that are used in gas separation applications microporous fillers are used. Soluble polymers of intrinsic microporosity are incorporated as microporous fillers. 

Khan MM, Filiz V, Bengtson G, Shishatskiy S, Rahman M, Abetz V. Functionalized carbon nanotubes mixed matrix membranes of polymers of intrinsic microporosity for gas separation. Nano res Lett 2012 7 504-15. Zhao Y, Jung BT, Ansaloni L, Winston Ho WS. Multiwalled carbon nanotube mixed matrix membranes containing amines for high pressure COJH separation. J Membr Sci 2014 459 233-43. 

Without the introduction of ladder-like moiety induced from benzodioxane, polyimides derived from distorted backbone units have potentials to retain the intrinsic microporosity because the imide linkage itself is formed as very rigid and flat two-dimensional structure. " Similar to Cardo-PIM, these polymers are based on bifluorene units, which have a 90° kink that prevents space-efficient packing or crystallization of the otherwise stiff polymer chains. Weber and Thomas synthesized bi-, tri- and tetra-functional bifluorene and reacted with dianhydride, di(acid chloride) or trimesoyl chloride for contorted polyimide and polyamide. The most microporous polyimide represents the BET surface area of 982 m g , providing much potential for highly permeable gas separation membranes. 

Poly(substituted acetylene)s such as PTMSP and PMP, amorphous fluoro-polymers like Teflon AF and Hyflon AD, polymers with intrinsic microporosity, and thermally rearranged (TR) polymers are the candidate polymers for highly permeable glassy polymer membranes. The high free volume in glassy polymers contributes to enhanced diffusion and permeation of small gas molecules. The gas permeation performances of these highly permeable polymers even surpass upper bounds for CO2/N2, CO2/CH4 and H2/CO2 separations. 

Interesting advances in the field of GS membrane materials are polymers with high-free volumes, such as poly(l-trimethylsilyl-l-propyne), poly(4-methyl-2-pentyne), and polymers of intrinsic microporosity [108]. Regarding the emerging application of CO2 capture, the copolymer class Pebax (Arkema) showed promising results. For instance, Bondar et al. [109] reported interesting values of CO2/N2 and CO2/H2 selectivity for different grades of Pebax membranes. 

MECHANISM OF GAS PERMEATION AND INTRINSIC MICROPOROSITY OF POLYPHENYLENE OXIDES MEMBRANES... 

Intrinsic microporosity of polyphenylene oxides corresponds to the throat and cavity model, where a cavity may have several throats. Effective diameters of the pore throats are in the range of ca. 0.4 nm at 77 K, increasing up to ca. 0.5 nm as the temperature rises to ambient. At these temperatures the intrinsic micropores are accessible for the molecules of simple gases. Apparently it is through these micropores that the gas transport in the dense polyphenylene oxides membranes occurs, with pore throats playing a role of a size caliber for the molecular sieve effect that manifests itself in membrane separations of certain gaseous mixtures. 

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