Polysaccharide gels chitin

In conclusion, this is the first report dealing with a basic polysaccharide gel that is thermally reversible and dealing with an intramolecular conversion of one gel to another gel in the solid phase. The chitin gels, which were produced by N-acetylation of the chitosan gel via the chitosan oxalate gel, and by 0-deacetylation of the partial 0-acetylated... 

There are also several water-soluble mixtures of polysaccharides, including those derived from seaweeds and marine animals, such as gum arabic, agar, algin, carrageenan, and chitin. These are hydrophilic. Their suspensions in water can be quite viscous and can readily form gels, and they can form viscous interfacial films around dispersed droplets and bubbles [821], They are used to stabilize suspensions, foams, and emulsions and are used in many different foods and medicines including, for example, ice cream [428,430], See also Ref. [822],... 

Amylopectins. — The effects of acrylamide graft copolymerization on the solution properties of amylopectin have been discussed. Amylopectin has been dyed with DyAmyl-L and used in this form as a substrate for the assay of a-amylase. Amylopectin has been treated with isocyanate derivatives of 4-amino-( 1,1-dimethyl ethyl)-3-(methylthio)-l,2,4-triazin-5(4/f)-one ( metribuzin ) or acid chloride derivatives of 2,4-dichlorophenoxyacetic acid ( 2,4-D ) and 2,2-dichloropropionic acid ( dalapon ), to produce controlled-release polymeric pesticide systems. The solvent system utilized for these reactions, a lithium chloride or bromide salt in AW-dimethylacetamide, allows dissolution of the reactant salt and facilitates analysis of the polymer product by such techniques as i.r., U.V., and n.m.r. spectroscopies and gel permeation chromatography. Derivatives of other naturally occurring polysaccharides, including amylopectin, cellulose, chitin, and dextran, were also prepared. 

Since polysaccharides have polar groups as well as some hydrophobic features, there can be inter residue interactions in a polysaccharide as well, but these attractions are expressed as interactions between different chains giving rise to such phenomena as crystallization which is prominently expressed in chitin and in cellulose. Other types of polysaccharides exhibit multistrand helix formation as in the case of sceleroglucan whose tendency for triple helix formation leads to unusual physical properties. Still other types of polysaccharides can form cross links in a more random way leading to gel formation as in the case of pectin, agarose and alginates. Chain interactions in other polysaccharides such as hyaluronan, chondroitin or... 

Hayashibara in Japan has produced Pullulan polysaccharide-based biodegradable films. Properties were reported to be similar to polystyrene. Aisero Chemical in Japan has produced biodegradable films and gels made by reacting chitin, found in the shells of crustaceans, with concentrated bases to form chitosan. Films manufactured from chitosan and cellulosic fiber have been reported to be hydrophilic, but not water-soluble, and to be good oxygen barriers. ... 

Abstract. The binding properties of granular alginic acid(H-alg.) and chitin to iodine, bromine, cadmium ion, calcium ion and cholesterol were investigated. Chitin-iodine and chitin-bromine compounds closely resemble those of H-alg. The amount of iodine included by these polysaccharides increased with a decrease in the concentration of potassium iodide (KI). The number of sugar residues bound to one iodine molecule extrapolated to 0 g of KI was around 6.0 for H-alg. and 6.4 for chitin. These saccharides, which do not form a gel in water, were found to also absorb KI and radioactive iodide or iodine in aqueous solution. H-alg. did not show as much affinity to cadmium ion and calcium ion and cholesterol in iso-propyl alcohol as metal-alginates. 

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