Synthesis chemically-cross-linked

Martino, M., and Tamburro, A. M. (2001). Chemical synthesis of cross-linked poly(KGGVG), an elastin-like biopolymer. Biopolymers 59, 29-37. 

For the preparation of nano- and microstructures there are numerous examples of endo- and exo-templates that have been used for the synthesis of particle- and pore structures from the nanometer to the micrometer scale. Templates can be inorganic, organic, or biological materials as are the materials or casts produced therefrom. The hardening process can be physical (crystallization from the melt, glass formation) or chemical (cross-linking, polycondensation). Templates usually have to be extracted in order to obtain the desired material. 

Liu C, Chun BS, Mather PT, Zheng L, Haley EH, Coughlin EB. 2002. Chemically cross linked polycyclooctene synthesis, characterization, and shape memory behavior. 

Ahmad, Z. Sagheer, F. A. Arbash, A. A. Ali, A. A. M., Synthesis and Characterization of Chemically Cross-Linked Polyimide-Siloxane Hybrid Films. 

As a result, the concentration of the elastically effective subchains (i.e., subchains contributing to the elasticity modulus) differs from the concentration of subchains Vch calculated from the amount of cross-linker used in the gel synthesis under the assumption of the formation of an ideal network, where all the cross-linker molecules are incorporated in such a way that they connect elastically effective network subchains. To describe this difference, the elasticity modulus G is represented as a sum of two components Gch and Gg associated with chemical cross-links and entanglements, respectively. This approach was called a two-network model. " °... 

The other possibility, at first examined by Wooley and co-workers [231,232] is to crosslink the corona of the micelles. These kinds of nanoparticles are designated by shell cross-linked knedel-Hke (SCK) micelles by these authors. Wooley et al. have applied this concept to a large variety of block copolymers, mainly hydrophobic-hydrophilic copolymers with PAA or quaternized PVP as the water-soluble block, which can be chemically cross-linked in their micellar form. A similar approach has been described by Armes and co-workers [233] for the synthesis of shell cross-linked micelles where core and shell are both hydrophilic. 

Liu, C., Chun, S. B., Mather, P. T., Zheng, L., Haley, E. H., Coughlin, E. B. (2002a), Chemically cross-linked polycyclootene Synthesis characterization and shape memory behavior. Macromolecules, 35,9868. 

MWNT/PVA aerogels have been fabricated employing the procedure for synthesis of chemically cross-linked cryogels (Kueseng et al., 2010). In this case, glutaralde-hyde was added to CNTs/PVA mixture to cross-link the polymer chains. 

J.L. Qiao, J. Fu, L.L. Liu, J. Zhang, J. Xie, G. Li, Synthesis and properties of chemically cross-linked poly(vinyl alcohol)-poly (acrylamide-co-diallyldimethylammonium chloride) (PVA-PAADDA) for anion-exchange membranes. Solid State Ionics, 214 (2012) 6-12. 

Responsive NC-gels are based on PNIPAAm and can be prepared by different strategies. The synthesis by free-radical polymerization follows the strategy of chemical cross-linking. 

It is notable that small peptides were retained on a cross-linked PEI column [37] but polypeptides over 20 residues were weakly retained or not at all. Possibly, small peptides were able to penetrate into the depth of the bonded phase while larger peptides could not. These packings were more useful for the separation of oligonucleotides, i.e. more acidic compounds. Lawson et al. [39] have shown the applicability of PEI-silicas for assessing the purity of precursor blocks, monitoring the chemical synthesis and isolating reaction products after synthesis. 

A chemical cross-hnking of MEEP was obtained by Shriver [606] by using polyethylene glycol (PEG) dialkoxide, which also forms polymer salt complexes. The cross-linked polymers were prepared by substituting a part (1 and 10 mole%) of the methoxyethoxyethoxy ethanol by PEG in the synthesis of MEEP. Contrary to the MEEP, the amorphous polymers obtained do not flow and are stable even at 140 °C. The maximum ionic conductivity at 30 °C, obtained after complexation with liSOjCFj, are 4.1x10" S cm for MEEP/PEG 1% complexed with 6.4 wt% salt and 3x10" S cm for MEEP/PEG 10% com-plexed with 8.9 wt% salt. These values are comparable with those obtained with the parent hnear polyphosphazenes. 

The basic chemical structure of ion exchangers is the same for most of them. They are quite often formed by PS-DVB cross-linked frameworks, with different kind and degree of functionalization, cross-linking degree, specific surface area and porosity. The large-scale industrial production of PS-DVB resins started more than 50 years ago [40]. The ready availability of these materials attracted the attention of chemists interested into chemical synthesis... 

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