A spectroscopic and viscometric study of the metal ion-induced gelation of the biopolymer chitosan

Brack, Hans‐Peter; Tirmizi, Syed Ahmed; Risen, William M.

doi:10.1016/s0032-3861(96)00780-x

Cited by 86 publications

(58 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Seemingly, a critical number of crosslinks per chain is required to allow the formation of a network structure. 27 Likewise, the loss tangent values decrease with increasing chitosan concentration, indicating that the crosslink density within the matrices increases the system elastic behavior (Fig. 4).…”

Section: Oscillatory Testmentioning

confidence: 90%

Rheological characterization of chitosan matrices: Influence of biopolymer concentration

Dı́ez-Sales

Dolz

Hernández

et al. 2007

J of Applied Polymer Sci

View full text Add to dashboard Cite

Viscoelastic properties of chitosan (CH), chitosan-poly(ethylene glycol) 400 (CH-PEG), and chitosanpoly(ethylene glycol) 400 with glyoxal as crosslinking agent (CH-PEG-Gly) systems were studied to analyze the effect of chitosan concentration (from 0.83 to 1.67%). Dynamic moduli increase as chitosan concentration increases for all systems. For CH and CH-PEG systems the loss modulus (G 00 ) is greater than the storage modulus (G 0 ) with predominance of the viscous over the elastic behavior. This corresponds to the characteristic behavior of solutions (nonstructured systems). The presence of PEG 400 induces a complementary reinforcement of the mechanical properties of the system. Except for the lowest chitosan concentration, when glyoxal was added to the CH-PEG systems, a gelled matrix was obtained. In this case, G 0 is greater than G 00 , and practically independent of frequency. This behavior is typical of threedimensional networks and indicates true gel formation, showing clear elastic behavior (tan d < 1). In creep and recovery analysis, CH-PEG-Gly systems exhibited distinct regions that were mathematically modeled using Burger's model. This analysis shows that the CH-PEG-Gly matrices (from 1.25 to 1.67%) recover almost totally (100%). Therefore, these matrices could be useful as systems for the development of films for topical hydrophilic drug delivery, and the levels of the residual viscosity (Z 0 ) or the complex viscosity (Z*) could be used to control drug release.

show abstract

Section: Oscillatory Testmentioning

confidence: 90%

Rheological characterization of chitosan matrices: Influence of biopolymer concentration

Dı́ez-Sales

Dolz

Hernández

et al. 2007

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…Despite the fact that these are primary amines, the pK a of chitosan in solution has been determined by the careful studies of Domard [5] to be 6.5. This anomaly, which is ascribed to polymer electrostatic and structural effects, makes it possible for the amine groups to coordinate metallic ions in the pH range of about 4-6 [1,3,6]. It also makes it possible to prepare chitosan-silica hybrid aerogels with reactive -NH 2 groups.…”

Section: Synthesesmentioning

confidence: 99%

“…These physical data, together with measured densities in the 0.23-0.32 g/cm 3 range, averaging 0.27 g/cm 3 for a representative set of clear monoliths, and the stoichiometric data, were used to construct a model for a SiO 2 -X aerogel. This model, shown in Figure 18.6, is consistent with all of the data, but it is not unique since the material is not crystalline.…”

Section: Propertiesmentioning

confidence: 99%

See 1 more Smart Citation

Biopolymer-Containing Aerogels: Chitosan-Silica Hybrid Aerogels

Yao¹,

Liu

Risen

2011

Aerogels Handbook

View full text Add to dashboard Cite

Hybrid aerogels comprising bioderived polymers and metal oxides have been explored in the case of chitosan and silica. The physical properties of homogeneous aerogels have been explored extensively and structural models have been formulated on the basis of the data. One attractive feature of these materials is that the chemically functional groups on chitosan can be employed to develop transparent transition-and lanthanide-containing monolithic aerogels. The functionality and chemical properties also enable formation of aerogels with a range of magnetic properties, with gold and other nanoparticles, and with attached polymeric structures. The structure and chemistry make it possible to explore diffusion control of reactions and physico-chemical control of nanoparticle growth. Some biocompatibility data are described. IntroductionOne class of organic-inorganic hybrid aerogels is a combination of a bioderived organic polymer and silica. Of particular interest in this class are aerogels that comprise chitosan or other polysaccharides which have functional groups that enable them to interact both with the silica-based components of the aerogel and with compounds that are added subsequently. The latter can be metal ions or any of a range of species that can react with or coordinate to pendant -NH 2 or carbohydrate -OH groups, in the case of chitosan. In the case of the polysaccharides pectic acid and alginic acid, the pendant groups are carboxyl, -COOH, and -OH, while in gellan gum and carrageenans, neutralized carboxylic groups, -COOM (typically, M ¼ Na

show abstract

“…It constitutes the principal fibril polymer in the shell of crustaceans and insects, and in the cell wall of certain fungi. Its derived product, chitosan, can be used as a coagulant in waste water treatment [1][2][3], in agriculture against fungal and bacterial diseases [4], in biomedical fields as drug-delivery vehicle [5][6][7], and in cosmetology for its capacity of water retention and film forming properties [5]. In food and dietary, chitosan is nowadays used as a supplement to reduce plasma cholesterol and triglycerides intestinal absorption.…”

Section: Introductionmentioning

confidence: 99%

Effect of organic and inorganic acids on concentrated chitosan solutions and gels

Hamdine

Heuzey

Bégin³

2005

International Journal of Biological Macromolecules

View full text Add to dashboard Cite

A spectroscopic and viscometric study of the metal ion-induced gelation of the biopolymer chitosan

Cited by 86 publications

References 23 publications

Rheological characterization of chitosan matrices: Influence of biopolymer concentration

Rheological characterization of chitosan matrices: Influence of biopolymer concentration

Biopolymer-Containing Aerogels: Chitosan-Silica Hybrid Aerogels

Effect of organic and inorganic acids on concentrated chitosan solutions and gels

Contact Info

Product

Resources

About