polymers, natural polymers

what are polymers in general and natural polymers in specific

1. Natural Polymers RAHMA & ASMA

2. Introduction: The word polymer has a Greek origin, which means many units (parts). Polymer is defined as a chemical substance of a high molecular mass formed by the combination of a large number of simple molecules called monomers. From the Greek word “ Poly ” means Many “ Meros ” mean Parts Many parts = Polymer Synthetic polymer Natural Polymer ( Polymer that occurs in nature Produced from living organism )

3. Polymerization: The process by which the monomer get combined & transformed into polymers is known as polymerization. Difference between polymers & macromolecules: A macromolecules may or may not contain monomer units e.g. Chlorophyll (C 55 H 72 O 5 N 4 Mg) is a macromolecule but not a polymer since there are no monomer units present so we can conclude that “ All polymers are macromolecules while all macromolecules may not be polymers in nature ”.

4. Classification of Polymers: 1. Based on source of origin: a) Natural Polymer: Those polymers which occurs in nature (plants & animals) e.g. Starch, cellulose, Natural rubber – Plant source Albumin, Gelatin ( Proteins ) - building blocks in animals b) Synthetic Polymer: prepared in lab with chemical reactions. e.g. Polyethene, synthetic rubber, PVC, nylon-66, Teflon. 2. Based on structure: Linear Polymer Branched chain polymer Cross-linked polymers or network polymer

5. 3. Based on Mode of Polymerization: Addition polymers : chain growth polymerization Condensation polymer : step growth polymerization 4. Based on Molecular forces: Elastomers: Fibers: Thermoplastics: Thermosetting plastics:

6. What is Natural Polymer? A natural polymer is a polymer that is found in nature and is not man made all natural or organic polymers come from living organisms. e. g. Guar gum, cellulose, starch, Albumin, Gelatin, Chitin, Chitosan. Why great attention for natural polymer? Biodegradable Biocompatible Non-toxic

7. CLASSIFICATION Plant Animal Microbes Polysaccharides e.g. Cellulose, Starch, Alginate. Proteins e.g. Gluten (Gelatin), Albumin. Polysaccharides e.g. Chitin (Chitosan), H y a l u r ona t e . Polyesters e.g. Poly(3- h y d r o x y l al k o n a te) dervitives. Polysaccharides e.g. Hyaluronate.  The natural polymers are classified based on source or structure. Classification of Natural polymers Based on source

8. CLASSIFICATION C l assific a tion of natural polymers based on structure. polysa c c h ri d es Cellulose, alginate, dextran, chitosan and Pollulan. Pol y peptides & Proteins gelatin, albumin, lecitin, and legumin. polynucleotides DNA RNA Pol y e s ters Poly (3- h d rox y alk o nate)

9. NATURAL RUBBER  Natural rubber is another example of a natural polymer.  It is made from only Carbon and Hydrogen.  It is a product of Isoprene polymerization. Isoprene n Natural rubber

10. PROPERTIES & ADVANTAGES  Most of natural polymers are naturally built by condensation polymerization  Natural polymers tend to be readily biodegradable - they show no adverse effects on the environment or human beings.  Non-toxic/ non-inflammatory - all of these materials are carbohydrates or proteins in nature and composed of repeating monosaccharide or amino acid units respectively. Hence they are non-toxic.  Biocompatible - their rate of degradation is generally inversely proportional to the extent of chemical modification  Highly porous  For molecular weight the average molecular weight that can be only defined  Easy and cheap to preparation and production in comparison with synthetic polymers  Capable of attachment with other molecules – most of these materials have variety of functional groups leading to readily modify  Easy availability and renewable resources

11. DISADVANTAGES  Microbial contamination during production due to their natural sources.  Batch to batch variation – as result to difference of resources and resource regions.  Slow Process – as the production rate is depends upon the environment and many other factors, it can’t be changed. So natural polymers have a slow rate of production.  potential impurities – may also result in unwanted immune reactions.  Heavy metal contamination – that often associated with herbal polymeric excipeints.

12. PHYSIOCHEMICAL PROPERTIES  Odorless, white or creamy-white powder  Chelates many transitional metal ions  Highly basic polysacharides  in acidic pH, it gets solubilized due to protonation of free amino groups and the resultant soluble polysaccharide is positively charged.  hydrophilic in nature thereby it has the ability to form gels at acidic pH.  Degraded by lysozyme to it’s by products glucosamine and n-acetyl glucosamine

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