Natural Water-Soluble Polymers 1 Polysaccharides

Polymers are mainly classified into two categories, natural and synthetic polymers (Table 30.1). Natural (water soluble) polymers are mostly obtained from natural sources. Naturally derived polymers with special focus on polysaccharides and proteins have become attractive in the biological applications of controlled release systems. Polysaccharides are a class of biopolymers constituted by either one or two alternating monosaccharides, which differ in their monosaccharide units in the length of a chain, in the types of the linking units, and in the degree of branching. ... 

Excipients used in the formulation usually include a mixture of a water-soluble polymer and a crystalline sugar. Mannitol and natural polysaccharides such as gelatin and alginates are used. Microencapsulation and complexation with ion exchange resins can be combined with additional flavors and sweeteners for taste masking of bitter drugs. The fairly complex nature of manufacture and scale-up contributes to... 

ATER-SOLUBLE POLYMERS (WSPs) are an important class of industrial polymers. They have many applications in solution and in the solid state. In solution, they are widely used as thickeners to control the rheology of various water-based formulations, such as latex paints, drilling muds, foods, cosmetics, and building materials. Chemically modified natural polysaccharides such as starch, cellulose, and guar are a large class of commercial water-soluble polymers. The appropriate chemical modification of these polysaccharides can lead to the modified solution properties needed for specific applications. 

Although there has been much activity to produce totally biodegradable water-soluble polymers for a variety of applications, especially for detergents, few complete successes have been registered beyond poly(vinyl alcohol), poly(ethylene oxides), and poly(aspartic acids). Almost aU efforts to obtain carbon chain polymers that are completely biodegradable have failed, at least in the short-term testing protocols currently in use. Some promising leads are noted in condensation polymers, polyaspartic acids, and acetals and in the modihcation of natural polysaccharides. 

As the name indicates, these polymers are obtained from nature. Polysaccharides and protein-based polymers were dominant among the naturally occurring water soluble polymers. 

Water soluble polymers are also now finding application in the area of packaging. For example polyvinyl alcohol pouches are used to dispense liquid detergent formulations. The pouch is placed in the washing machine and the polyvinyl alcohol slowly dissolves to release the liquid. The emphasis nowadays is to use natural polymers, both polysaccharides and proteins, as packing materials because of their ability to biodegrade and recent advances in this area are covered in Chapter 10. 

A variety of water-soluble polymers has been used for the preparation of hydrogels. This includes polymers of (semi) natural origin, such as proteins and polysaccharides, but also synthetic polymers, like block copolymers of... 

Naturally occurring polysaccharides and their derivatives form the predominant group of water-soluble species generally used as thickeners to impart viscosity to treating fluids [1092]. Other synthetic polymers and biopolymers have found ancillary applications. Polymers increase the viscosity of the fi ac-turing fluid in comparatively small amounts. The increase in fluid viscosity of hydraulic fracturing fluids serves for improved proppant placement and fluid loss control. Table 17 summarizes polymers suitable for fracturing fluids. 

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