Polysaccharide gels mechanism

Rees, D. A. (1969). Structure, conformation, and mechanism in the formation of polysaccharide gels and networks. Adv. Carbohydr. Chem. Biochem. 24 267-332. 

Rees, D. A., Structure, Conformation, and Mechanism in the Formation of Polysaccharide Gels and Networks, 24, 267-332... 

Coviello T, AUiaique F, Parisi C, Matricardi P, Bocchinfuso G, and Grassi M. A new polysaccharidic gel matrix for drug delivery Preparation and mechanical properties. J. Control. Rel. 2005 102 643-656. 

STRUCTURE, CONFORMATION, AND MECHANISM IN THE FORMATION OF POLYSACCHARIDE GELS AND NETWORKS... 

Rees, D. A. In "Structure, Conformation and Mechanism in the Formation of Polysaccharide Gels and Networks" Wolfrom, M. L. Tipson, R. S. Horton, D., Eds. Advances in Carbohydrate Chemistry and Biochemistry Academic Press New York, 1970 ... 

Sriamorasak, P. and Kennedy, R. (2006) A novel gel formation method, microstructure and mechanical properties of calcium polysaccharide gel films, Ira. J. Pharm., 323, 72-80. 

An example ofthe mechanical spectra (dependences of G, G" and T] on CO, the SI physical unit is the Pascal-second, Pa.s, equivalent to N.s/m or kg/m s) of a polysaccharide gel is shown in Figure 7.37. The gel has a much higher value of the storage modulus G than the value of the loss modulus G and the gel therefore essentially behaves as a sohd. Both modules are independent of strain rate (co) and the gel is therefore highly elastic. The complex dynamic viscosity (t] ) decreases with increasing strain rate (co) values as the gel becomes more fluid, which means that it is thixotropic. 

Figure 7.37 Typical mechanical spectra of polysaccharide gels ...

Dextran gels have been utilized since the late 1950s (1) for the separation of biopolymers. First attempts on Sephadex (2-5) and Sephadex/Sepharose (6-8) systems are documented for hydrolyzed and native starch glucans. Up until now, particularly for the preparative and semipreparative separation of polysaccharides, a range of efficient and mechanically stable Sephacryl gels (9-14) have been developped. 

Agarose gels have been used for more than two decades to separate polysaccharides (17-22). In particular, Sepharose CL 2B is widely used (6-8) to separate native starch, but continuously improved mechanical and chemical stability made all of the Sepharose CL gels perfect systems for the analysis of high molecular and broad distributed polysaccharides (23-28). 

Polysaccharide-based CSPs incorporate derivatives of cellulose and amylose adsorbed on silica gel. The selectivity of these CSPs depends upon the nature of the substituents introduced during the derivatization process. The secondary structure of the modified polysaccharide is believed to play a role in selectivity, but the chiral recognition mechanisms have not been fully elucidated [55]. 

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