Polymers natural origin

Polymers are very large organic molecules that are either made synthetically or are of natural origin, and find use as plastics, rubber, fibers, and coatings. Polymers were first produced commercially in 1860 by modification of cellulose from wood or cotton, followed by a fully synthetic product made from phenol and formaldehyde in 1910. 

Protective colloids can be divided into synthetic and natural materials. Table 3 classifies the pharmaceutical gums, thickeners, and other hydrophilic polymers according to their origins [72]. Protective colloids of natural origin, such as gelatin, acacia, and tragacanth, have... 

Polymers are substances whose molecules are very large, formed by the combination of many small and simpler molecules usually referred to as monomers. The chemical reaction by which single and relatively small monomers react with each other to form polymers is known as polymerization (Young and Lovell 1991). Polymers may be of natural origin or, since the twentieth century, synthesized by humans. Natural polymers, usually referred to as biopolymers, are made by living organisms. Common examples of biopolymers are cellulose, a carbohydrate made only by plants (see Textbox 53) collagen, a protein made solely by animals (see Textbox 61), and the nucleic acid DNA, which is made by both plants and animals (see Textbox 64). 

Synthetic and natural polymers have been investigated which are biodegradable and biocompatible. The nanospheres are formed by precipitation of synthetic polymers or by denatu-ration/solidification of polymers of natural origin. Four techniques have been reported for preparing nanoparticles from synthetic preformed polymers. These include ... 

A variety of water-soluble and water-insoluble polymers of both synthetic and natural origin [31] have been studied as bioadhesives. These polymers are used mainly to... 

Although it seems obvious that there is a coimection between the natural origin of a polymer and its biodegradabihty this is one of the most common misunderstandings with respect to biopolymers. Biodegradabihty is a function of the chemical structure of a molecule and there is no dependence on its origin. This is the reason why synthetic, man-made polymers can also be biodegradable if their structure obeys certain rules. 

The exhaustible nature of the oil reserves and the pollution that oil-based technological polymers can have on the environment has rekindled an interest in polymers of natural origin, in particular the biotechnological polymers. Until now, however, the polyhydroxyalkanoates are the only biotechnological polymers that have been developed industrially, occupying a notable position as biodegradable and biocompatible biomaterials for temporary use [1, 2]. 

I.6.I. Chiral Phases Based on Polymers of Natural Origin... 

Polymers are abundantly present in nature, in vegetable and animal tissues (mainly as cellulose and proteins). Several technically used polymers have a natural origin they are being used as technical materials as they are harvested from natural materials ( natural polymers ). 

Other polymers are partly from a natural origin the chain molecule has grown in a living tissue, but has been chemically modified into a half-synthetic polymer . 

Wood and, polymers. Natural materials as well as materials manufactured from plant or animal origin, such as wood, cotton, paper products, wool, and leather, etc., are fully biodegradable under aerobic conditions. (Dexter)5 Plastics are materials that consist mainly of highly polymeric, organic compounds. Also, nondegradable polymer may become degradable by a combined chemical, physical, and biological attack.64,67... 

Films are continuous, thin, clear, coloured or opaque materials derived from organic polymers. Most polymers are synthesised whereas the cellulose -based films mentioned previously are mainly of natural origin. 

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