Graft polymerization chitosan

An alternative to the experiments just described is the esterification of chitosan with the use of lactide or polylactide for example, Skotak et al. [59] prepared chitosan derivatives following a one pot approach by grafting L-lactide oligomers via ring-opening polymerization. Chitosan (600 mg) was dissolved in 10 mL of... 

Ding Z, Chen J, Gao S, Chang J, Kang ET. Immobilization of chitosan onto poly-l-lactic acid fihn surface by plasma graft polymerization to control the morphology of fibroblast... 

A water-soluble chitosan (WSC)/chondroitin-6-sulfate (ChS) polyelectrolyte complex (PEC) was covalently immobilized onto the PHBHV surface membranes via ozone-induced oxidation and PA A graft polymerization [48], These PHBHV membranes possess antibacterial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. It was demonstrated that WSC/ChS PEC immobilization improved the cytocompatibility of the PHBHV membrane and presented an antibacterial activity for the development of tissue engineering. 

With the development of enzymatic polymerization in solution, also first accounts for SIP appeared. Loos et al. [350] reported on enzymatic surface polymerization of glucose-l-phosphate with potato phosphorylase as the catalyst resulting in oligo- or poly-(a,l- 4)-D-glucopyranose. As initiator sites, immobilized malto-heptaose was used. Enzymatic grafting of hexyloxyphenol onto chitosan is reported by Payne and coworkers [351]. 

Phase transfer catalysts have been grafted onto the surface of porous capsules to facilitate product purification after reaction, and many types of immobilized cells, mycelia, enzymes, and catalysts have been encapsulated in polymers such as PDMS, PVA, or cellulose. In the specific case of PVA, they are named Lenti-kats, as commercialized by Genialab and used for nitrate and nitrite reduction and in the synthesis of fine chemicals. These beads show minimized diffusion limitations caused by the swelling of the polymeric environment under the reaction conditions. To avoid catalyst leaching, enlargement can be realized by linking them to, e.g., chitosan. 

Redox catalyzed polymerizations using ferrous ion and peroxidative compound have been reported to be usefiil for grafting reaction of natural fiber such as chitosan (79). Ascorbic acid is also used instead of the ferrous ion 80). Ascorbic acid is reported to produce activated oxygen under mild condition, and recently it is used for linear polymer synthesis of sugar alcohol derivatives containing vinyl group 81). These catalysts, which promote the reaction under... 

Fig. 10 (a) Molecular structure of a water-soluble and crosslinkable chitosan derivative (CML) obtained by grafting methacrylic acid and lactic acid onto the pendant amine groups of chitosan. The structure does not represent the real ratio between each monomer unit, (b) Illustration of the chitosan hydrogel network linked by alkyl chains, which are formed via C=C polymerization [116]... 

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