Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Chitosan chemical structure

As a polycation, chitosan spontaneously forms macromolecular complexes upon reaction with anionic polyelectrolytes. These complexes are generally water-insoluble and form hydrogels [90,91]. A variety of polyelectrolytes can be obtained by changing the chemical structure of component polymers, such as molecular weight, flexibility, fimctional group structure, charge density, hydrophilicity and hydrophobicity, stereoregularity, and compatibility, as... [Pg.158]

Fig. 8 Preparation of amphiphilic polysaccharide. Chemical structures of deoxycholic acid-modified chitosan (a) and Phe-modified pectin (pectin-gra/t-Phe) (b). SEM image of nanoparticles prepared from pectin-gra/t-Phe (c)... Fig. 8 Preparation of amphiphilic polysaccharide. Chemical structures of deoxycholic acid-modified chitosan (a) and Phe-modified pectin (pectin-gra/t-Phe) (b). SEM image of nanoparticles prepared from pectin-gra/t-Phe (c)...
FIGURE 3.1 Chemical structures of chitosan, iV-trimethyl chitosan hydrochloride, and chitosan-TBA conjugate. [Pg.58]

The size of the polyplex depends not only on the chemical structure of chitosan but also on the ratio between chitosan and DNA used for polyplex formulation, the concentrations of polymers, and formulation technique. This is commonly described in terms of N/P ratio, the ratio of protonatable polymer amines to... [Pg.150]

Fig. 6.4 Chemical structure of (a) chitosan and (b) N-trimethyl chitosan chloride (from Kotze et al. 1998)... Fig. 6.4 Chemical structure of (a) chitosan and (b) N-trimethyl chitosan chloride (from Kotze et al. 1998)...
Structure XII The chemical structure of chitosan. The amine groups on the polymer have a p/C in the range 5.5-6.5, depending on the source of the polymer... [Pg.298]

The same procedure of catalyst synthesis applied to other polysaccharides, such as -carrageenan and chitosan, allowed data on the influence of the chemical structure of the support to be obtained. The differences in turnover numbers (moles of product per moles of Pd per hour), close to 500 for alginates, 190 for carrageenan, and only 40 for chitosan, indicated that the activities were correlated to the electrostatic properties of the support. Carrageenans only bear one sulfate group per two saccharide monomers, while alginate presents one carboxylic group... [Pg.189]

Fig. 7 a-g Chemical structures of biohybrid homopolymer amphiphiles. a L-Cysteine-grafted polybutadiene, b Glycosylated polybutadiene, c Glycosylated poly(2-oxazoline). d V,V-l)ialkyl chitosan. e Amphiphilic poly(L-lysine). f PEGylated poly(Z-L-lysine). g Lipid-lysine dendron... [Pg.177]

There are many kinds of natural biodegradable polymers. They are classified into three types according to their chemical structures, i.e., polysaccharides, polypeptides/proteins and polynucleotides/nucleic acids. Among them, polysaccharides, such as cellulose, chitin/chitosan, hyaluronic acid and starch, and proteins, such as silk, wool, poly( y-glutamic acid), and poly(e-lysin), are well known and particularly important industrial polymeric materials. [Pg.772]

In a similar vein, a series of papers published between 2002 and 2008 contains spectacular claims of highly enantioselective asymmetric additions of water to styrenes, unsaturated carboxylic acids, or simple terminal alkenes [34-Al]. The catalysts used are of the heterogeneous type and based on chiral biopolymers such as wool, gelatin, or chitosan as solid supports (sometimes in combination with silica or ion-exchange resins) that are doped with transition metal salts. This series of papers contains spectacular claims, insufficient experimental data, and erroneous chemical structures for the biopolymers used. As earlier work from the same group of authors on asymmetric catalysis on bio-polymeric supports is irreproducible [42], one is well advised to await independent confirmation of those results. [Pg.130]

The interfacial polyaddition of chitosan used as stabilizer with two biocompatible costabilizers, Jeffamine D2000 and Gluadin, and a linking diepoxide in presence of an inert oil results in thin but rather stable nanocapsules (see Fig. 19a). Since both water and oil soluble aminic costabilizers can be used, these experiments show the way to a great variety of capsules with different chemical structure [185]. [Pg.33]

In order to modify or enhance specific properties of chitosan, chemical derivatives have been synthesized by using the amines and hydroxyl groups in the molecular structure. Some examples include trimethyl chitosan, glycol chitosan, carboxymethyl chitosan, half-acetylated chitosan, and thiolated chitosan." ... [Pg.1244]

FIGURE 53.6 Chemical structure of (a) chitin and (b) chitosan, where n stands for the whole numbers signifying the number of monomers present in the polymer. [Pg.1262]

The brief examples of chitosan derivatives, their chemical structure, characteristics features, and modes of action are highlighted in Table 6.1. [Pg.227]

Table 6.1 Some of the most important chitosan (HO-CH-NH2) derivatives, their chemical structure, and characteristic features... Table 6.1 Some of the most important chitosan (HO-CH-NH2) derivatives, their chemical structure, and characteristic features...
Fig. 3.1 Chemical structure of chitin and deacetylated chitin (chitosan)... Fig. 3.1 Chemical structure of chitin and deacetylated chitin (chitosan)...
Chemical structure of chitosan, a natural thermo-sensitive polymer. [Pg.269]

Chitosan derivatives. Due to the chemical structure of chitosan, specific reactions can be performed on the amino group in C-2 position of the glucosamine unit, especially by reductive amination reaction. Also two -OH groups are available on C-3 and C-6 positions [1,2]. The more interesting is to test reactions on the C-2 position. Two different types of derivatives may be recognized (i) derivatives obtained by chemical modification and introduction of different substituents, (ii) grafted copolymers on C-2 position. [Pg.72]

Gonzalez, V., Guerrero, C. and Ortiz, U. (2000) Chemical structure and compatibility of polyamide-chitin and chitosan blends. Journal of Applied Polymer Science, 78(4), 850-857. [Pg.83]


See other pages where Chitosan chemical structure is mentioned: [Pg.152]    [Pg.32]    [Pg.412]    [Pg.1484]    [Pg.95]    [Pg.95]    [Pg.335]    [Pg.60]    [Pg.132]    [Pg.21]    [Pg.107]    [Pg.115]    [Pg.115]    [Pg.157]    [Pg.275]    [Pg.625]    [Pg.1261]    [Pg.513]    [Pg.560]    [Pg.804]    [Pg.149]    [Pg.44]    [Pg.44]    [Pg.46]    [Pg.199]   
See also in sourсe #XX -- [ Pg.108 ]

See also in sourсe #XX -- [ Pg.60 ]

See also in sourсe #XX -- [ Pg.107 ]

See also in sourсe #XX -- [ Pg.74 , Pg.269 ]

See also in sourсe #XX -- [ Pg.296 , Pg.296 ]

See also in sourсe #XX -- [ Pg.22 ]




SEARCH



Cellulose-chitosan composite chemical structure

Chemical structure chitosan membranes

© 2024 chempedia.info