Crosslinking with Epichlorohydrin

Hercosett 125 (Hercules) reactive cationic polymer formed by condensation of adipic acid and diethylenetriamine, then partially crosslinked with epichlorohydrin... 

Breslow et al. (13) have prepared an insolubilized cyclodextrin resin by crosslinking with epichlorohydrin. The resin was used for the chlorination of anisole via a three-step process. The column was loaded with anisole, that is, the available cycloclextrin cavities were filled with anisole. Aqueous HOCl was passed through and the product, 99% / -chloroanisole, was eluted with tetrahydrofuran. 

The authors first mentioned investigated an anion-exchange membrane consisting of polyethylene imine crosslinked with epichlorohydrin in equilibrium with KC1 solutions. The concentration of Cl- ions and K+ ions in the membrane were determined analytically. The mobility of the Cl- ions in the membrane was determined according to the principle of the moving boundary. Thus in a membrane strip a sharp boundary is formed between the OH- and Cl- ions. This boundary will move under the influence of an electric field. This may be made visible with the aid of an indicator. The speed of the boundary is determined by the slowest ion, by consequence the Cl- ion in this instance. 

The water-absorption rate of the polymers can be increased by use of capillary action. It is reported that fibrous carboxymethyl celluloses, which were crosslinked with epichlorohydrin and had the carboxymethylation degree of 0.2-0.4, had high water-absorption rate of 20-40 ml/ g-polymer/min. 

Aminated starches have been further converted. For example, dimethyl-aminoethyl starch could be converted into glycosides by alcoholysis,2442 phosphorylated with sodium dihydrogenphosphate, and oxidized with hydrogen peroxide to carboxyl derivatives.520 Additional information on this subject can be found in Section VII. 2-Hydroxypropyltrimethylammonium chloride starch has been crosslinked with epichlorohydrin.2443 In contrast to animation, which requires basic solutions, phosphorylation occurs at pH 6.2444... 

Poly(amino acids)2892 and polypeptides2893 can also be grafted onto starch. Starch was first alkylated in the presence of lithium naphthalene, and then the alkoxy derivatives were reacted with /V-carboxy anhydrides. Poly(amide amines) were produced by reacting amines with dioic acids on starch and then crosslinking with epichlorohydrin or 1,2-dichloroethane 2894 Grafting of starch with a synthetic polymer chain, for instance, polystyryl carboxylate anions prepared by an anionic polymerization, can be carried out on a blend of starch and cellulose functionalized by sulfonation, mesylation, or tosylation. In this manner, cellulose-starch graft copolymers were prepared.2895... 

Sreedhar, B., Chattopadhyay, D.K., Karunakar, M.S.H., and Sastry, A.R.K. 2006. Thermal and surface characterization of plasticized starch polyvinyl alcohol blends crosslinked with epichlorohydrin. J. Appl. Polym. Sci. 101 25-34. 

Dextran mixed with PVP and poly(vinyl acetate) was crosslinked with epichlorohydrin to fonn beads containing herbicides. Controlled release of herbicnles. Rehab et at., 1991... 

Figure 3.9 Scanning electron micrograph of surface morphology of hydrogels prepared with pachyman (A), CMP (B) and HMP (C) crosslinked with epichlorohydrin (A and C reproduced with permission from [77] and B reproduced with permission from [213]).

Figure 7 The chemical structure of CMC gel crosslinked with epichlorohydrin.

In addition, molecular imprinting technique is also used in anion recognition. Ozkutuk et al. reported the preparation and adsorption ability of the phosphate-imprinted chitosan-succinate beads [34]. Chitosan was modified with succinic anhydrides firstly. Second the mixture of chitosan-succinate and Fe (III) ions stirred continuously at room temperature. And Na3P04 was added to Fe (III)-chitosan-succinate mixture. This mixture was slowly dropped into NaOH solution to form beads. Afterwards, beads were crosslinked with epichlorohydrin and the template (phosphate ions) was removed using IM KOH solution. Selective cavity for the phosphate ion was obtained in the phosphate imprinted metal-chelate polymer. The phosphate-imprinted metal-chelate polymer was used in the adsorption-desorption process. The adsorption process was fast and equilibrium was reached around 30 min. The adsorption behaviour of this system was described approximately by the Langmuir equation. 

Miao, J., Chen, G., Gao, C., and Dong, S. 2008. Preparation and characterization of N,0-carboxymethyl chitosan/polysulfone composite nanofiltration membrane crosslinked with epichlorohydrin. Desalination 233 147-156. 

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