Polymers with intrinsic microporosity

Figure 2.5 Molecular building units of polymers with intrinsic microporosity [69]. Reproduced with permission of the PCCP Owner Societies.

Polymers with intrinsic microporosity (PlMs) have recently been introduced... 

The intensive search for other types of microporous materials that started less than a decade ago resulted in the development of polymers with intrinsic microporosity (PIMs see Chapter 9, Section 3.8) and... 

M. Heuchel, D. Fritsch, P. M. Budd, N. B. McKeown, D. Hofmann, Atomistic packing model and free volume distribution of a polymer with intrinsic microporosity (PIM-1), J. Membr. Sci., 318, 84-99 (2008). 

Polymers with intrinsic microporosity, abbreviated as PIMs, were developed for the first time by McKeown and Budd. The general design strategy involves incorporation of extended aromatic components within a rigid polymer network in order to imitate the structural layout of graphene sheets of activated carbons.The principle behind the synthesis of PIMs employs non-reversible condensation reactions to form polymers. These polymers cannot efficiently fill the space and pack together due to components that are rigid and ladder-like, and thus force the backbone of the polymer to twist or turn. 

The book was initially eonstrueted with a historical development sequenee of porous polymers eombined with illustrations of structure-property correlations. Eaeh ehapter provides an example of a particular element of porous polymers. Chapter 1 provides a summary of porous polymers and discusses the relationship between structure and function. In Chapter 2, the design principles of porous polymers are diseussed and modification methods are introdueed, while Chapter 3 introduees the synthetic routes and reactions used in polymerization. An understanding of these reactions is essential if we are to understand the origin of the ordered or amorphous structure of porous polymers. Chapter 4 describes the first porous polymers, developed in the 1990s and named hypercrosslinked polymers or Davankov-type resins. Chapter 5 focuses on the first soluble polymer with intrinsic microporosity that was reported in 2002. Meanwhile, Chapter 6... 

Figure 4.11 Synthesis of polymers with intrinsic microporosity (a) PIM-1 and (b) PIM-7.

Table 4.9 Physical properties and permeation properties of polymers with intrinsic microporosity (PIMs)...

As a whole, McKeown and Budd present criteria for polymers with intrinsic microporosity by using more than 100 monomers."" With the analysis by BET sorption measurement, positron annihilation lifetime spectroscopy and atomistic computer simulation, they emphasized the importance of microporous materials in several applications. 

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. 

In addition, the polymers of intrinsic microporosity (PIMs), such as phthalocyanine networks and the Co phthalocyanine network-PIM (CoPc20), display high specific surface area, as confirmed by the N2 adsorption isotherm at 77 K, and by the adsorption of small organic probe molecules from aqueous solutions at 298 K [236], This material is basically microporous with an increased concentration of effective nanopores. 

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] ... 

Du N, Robertson GP, Song J et al (2009) High-performance carboxylated polymers of intrinsic microporosity (PIMs) with tunable gas transport propertiesf. Macromolecules 42 6038-6043... 

If the answer to both these questions is yes , then the polymer can be said to have intrinsic microporosity [3,4] intrinsic because it is a consequence of the molecular structure and microporosity because we are dealing with micropores in the sense defined by lUPAC [2], This chapter introduces a concept for creating just such polymer structures, outlines the properties of the archetypal polymer of intrinsic microporosity , PIM-1, and describes recent results for PIM-1 obtained in the course of a European collaborative research project [5]. 

Figure 7.17 Influence of porous aromatic frameworks (PAFs) on the CO2 permeability coefficient of different glassy polymers, polyftrimethylsilyl propyne) (PTMSP), PMP, and polymers of intrinsic microporosity (PIM)-l, with respect to the aging phenomenon.

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. 

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. 

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