Functionalization porous polymers

Tripp JA, Stein JA, Svec F, Frechet JMJ, Reactive filtration Use of functionalized porous polymer monoliths as scavengers in solution-phase synthesis, Org. Lett., 2 195-198, 2000. 

Figure 4,9. Different types of polymer particles for liquid chromatography. Macroporous polymer (A), surface functionalized porous polymer for cation-exchange chromatography (B) and electrostatically agglomerated anion-exchange particle (C).

Kimmins, S.D., Cameron, N.R., 2011. Functional porous polymers by emulsion templating recent advances. Advanced Functional Materials 21, 211-225. 

Various click chemistries, building the foundation for most post-polymerization modifications, have also been applied for fabrication of reactive porous polymer monoliths [118-125]. Click reactions include alkyne-azide, thiol-ene, and thiol-yne reactions, and these reactions can be conducted under mild conditions, unlike many other polymer graft reactions. Svec and coworkers used the thiol-ene reaction to functionalize porous polymer monoliths [121]. Monoliths were thiolated with cysteamine, followed by cleavage of the disulfide bonds using tri(2-carboxylethyl) phosphine to expose the desired thiol groups. Then, lauryl methacrylate monomers were clicked onto the monoliths using either heat or UV initiation. Thiol-yne and... 

Peterson DS, Rohr T, Svec FK, Frechet JMJ (2003) Dual-function microanalyt-ical device by in situ photolithographic grafting of porous polymer monolith integrating solid-phase extraction and enzymatic digestion for peptide mass mapping. Anal Chem 75 5328... 

Another approach is similar to that used in for the preparation of polymer-layer open tubular GC columns (PLOT). Horvath s group prepared capillaries with a porous polymer layer as shown in Fig. 13 by in situ polymerization of vinylbenzylchloride and divinylbenzene [183]. The reaction of the N,N-di-methyldodecylamine with chloromethyl groups at the surface simultaneously afforded strong positively charged quaternary ammonium functionalities and attachment of C12 alkyl chains to the surface. The unreacted chloromethyl groups... 

The main emphasis in this chapter is on the use of membranes for separations in liquid systems. As discussed by Koros and Chern(30) and Kesting and Fritzsche(31), gas mixtures may also be separated by membranes and both porous and non-porous membranes may be used. In the former case, Knudsen flow can result in separation, though the effect is relatively small. Much better separation is achieved with non-porous polymer membranes where the transport mechanism is based on sorption and diffusion. As for reverse osmosis and pervaporation, the transport equations for gas permeation through dense polymer membranes are based on Fick s Law, material transport being a function of the partial pressure difference across the membrane. 

Kitagawa S, Kitaura R, Noro S. Functional porous coordination polymers. Angew Chem Int Ed 2004 43 2334-2375. 

Functionalized polymers are of interest in a variety of applications including but not limited to fire retardants, selective sorption resins, chromatography media, controlled release devices and phase transfer catalysts. This research has been conducted in an effort to functionalize a polymer with a variety of different reactive sites for use in membrane applications. These membranes are to be used for the specific separation and removal of metal ions of interest. A porous support was used to obtain membranes of a specified thickness with the desired mechanical stability. The monomer employed in this study was vinylbenzyl chloride, and it was lightly crosslinked with divinylbenzene in a photopolymerization. Specific ligands incorporated into the membrane film include dimethyl phosphonate esters, isopropyl phosphonate esters, phosphonic acid, and triethyl ammonium chloride groups. Most of the functionalization reactions were conducted with the solid membrane and liquid reactants, however, the vinylbenzyl chloride monomer was transformed to vinylbenzyl triethyl ammonium chloride prior to polymerization in some cases. The reaction conditions and analysis tools for uniformly derivatizing the crosslinked vinylbenzyl chloride / divinyl benzene films are presented in detail. 

Generally, two different procedures have been adopted for preparation of MIPs. They involve either covalent or non-covalent complex formation of a template and complementary monomers with apt functional groups. [19]. Co-polymerization of this complex with a cross-linking monomer in a porogenic solvent solution, followed by removal of the template, results in formation of the porous polymer material with recognition sites complementary in size and shape to molecules of the target compound that can next be determined as an analyte. 

Similarly, a monolithic polymer of PolyHIPE functionalized with tris(aminoethyl)amine captures acid chlorides in solution with high efficiency (entry 36).42 Contrary to suspensions of polymer beads, the porous polymer monolith is used in a flow-through reaction format. 

Say, R., Emir, S Garipcan, B. et al. (2003a) Novel methacryloylamidophenylalanine functionalized porous chelating beads for adsorption of heavy metal ions. Advances in Polymer Technology, 22(4), 355-64. 

Porous polymers containing various metal chelates bound to nitrogen functionalities have been used to separate oxygen from argon, nitrogen, and carbon monoxide [25]. The porous polymer is synthesized with pyridyl functional groups, which serve as an axial base for the metal chelate in coordinate bond formation between the metal chelate and the polymer. It also serves to activate the metal complex for oxygen coordination. 

Fig. 6.20. Schematics for the preparation of monolithic capillary columns. First, the bare capillary is filled with the polymerization mixture (step a) that contains functional monomer, crosslinking monomer, initiator, and porogenic solvent. Polymerization (step b) is then initiated thermally or by UV irradiation to afford a rigid monolithic porous polymer. The resulting monolith within the capillary is washed (step c) with the mobile phase using a pump or electroosmotic flow and used as for the CEC separations.

The synthesis of phenolic-formaldehyde and melamine-formaldehyde resins in the presence of fumed silica allows obtaining porous organic materials with a differentiated porous structure and surface properties. The pore characteristics of the studied resins in dry state were determined from nitrogen adsorption isotherms. The differences in surface character of the synthesized polymers were estimated satisfactorily by XPS spectra showing the presence of various functional groups. The adsorption/desorption mechanism of water and benzene on the investigated porous polymers was different due to differentiated hydrophobicity of the bulk material. 

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