Poly galactoses

CMC acts as a viscosity improver or thickener (textile additive, cosmetics, cakes) and as a protective colloid in emulsion polymerization. 

The most important of the poly(j8-glucosamines) found in nature have the 2-position hydroxyl groups in the glucose residue replaced by an amino group. They are, therefore, poly(j8-2-amino-2-deoxy-glucopyranoses). 

Chitin is poly[j5-(l- 4)-iV-acety 1-2-amino-2-deoxyglucopyranose]. The shells of crustaceans contain 20-25% chitin together with 70% calcium carbonate. It is the second most important biological animal structural material after the protein collagen. 

Chitin is obtained by first dissolving away the calcium carbonate with 5 % hydrochloric acid. Then any protein is removed with pepsin or trypsin. Next comes the deacetylation of the chitin to chitosan, whereby the enzymatic treatment is followed by using a 5 % caustic soda solution, followed by treatment with concentrated alkali in ethanol/ethylene glycol. 

Hyaluronic acid is an alternating copolymer, namely poly[jS-(1 4)-glucuronic acid-alt-j8-(l 3)-2-acetamido-2-deoxyglucose] (Table 31-7). It occurs in the lubricating fluid (synovial fluid) of the joints and the eyes and acts as a kind of cement for the extracellular basic material of connective tissues. 

---

Sugars usually occur in nature as polysaccharides containing one or other enantiomeric form, D or L. There are however, exceptions, fortunately few, such as the galactan (i.e. poly-galactose) from snails which produces both D- and L-galactose upon hydrolysis (93). 

The addition of amphiphilic polymer in o/w or w/o/w emulsion systems is also useful to give surface functionality to MSs and NSs. Liang et al. reported preparation of NSs from poly(y-glutamic acid)-h-PLA, immobilizing galactose residues on the surface by an o/w emulsion method, and in vivo specific delivery of aniticancer... 

As indicated later (see Section VI,8), on addition of the chloride of praseodymium, europium, or other lanthanides to mono- or poly-sac-charide phosphates in D20, the signals of carbon atoms substituted with phosphate groups are recognizable, as they are displaced, relative to the rest of the 13C-n.m.r. spectrum.155 However, this diagnostic method is not applicable to sulfated polysaccharides, as signal displacements were not observed on addition of praseodymium or europium chloride to a solution of a,/3-D-galactose 6-sulfate or its sodium salt.156... 

Chart 2.6 Structure of block copolymer based on PEO and poly(benzyl methacrylate) (PBMA) containing /3-D-galactose unit. 

Sharma et al. [44] Lactose Milk and dairy products Lactase and galactose oxidase (GaO)/in Langmuir-Blodgett (LB) films of poly(3-hexyl thiophene) (P3HT)/stearic acid (SA) Indium-tin-oxide coated glass plates/0.4 V vs. Pt reference electrode ... 

---