1. Natural Polymers
By
Mr. S. G. Laware
Asst. Prof., Dept. of Pharmacognosy,
P.R.E.S’s College of Pharmacy (For Women), Chincholi.
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” “Meros”
means Many mean Parts
Many parts = Polymer
Natural Polymer Synthetic 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
(C55H72O5N4Mg) 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:
a) Linear Polymer
b) Branched chain polymer
c) Cross-linked polymers or network polymer
5. 3. Based on Mode of Polymerization:
a) Addition polymers:
b) Condensation polymer:
4. Based on Molecular forces:
a) Elastomers:
b) Fibers:
c) Thermoplastics:
d) 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
8. Polysaccharides from plant source: Cellulose
• Major source of cellulose are plant fibers like cotton (cellulose content in cotton fiber
is 90%, cotton wood – 40-50%)
• Linear chain of several hundred to over ten thousand ß(1-4) linked D-Glucose units
having the formula (C6H10O5)n.
• Cellulose is an important structural component of the primary cell wall of green
plants.
• Cellulose is mainly used to produce paperboard & paper.
• Smaller quantity are converted into a wide variety of derivative products such as
cellophane and rayon.
• Some animals, particularly ruminants & termites, can digest cellulose with the help of
symbiotic micro-organisms that live in their guts.
9. • In human nutrition, cellulose is a non-digestable constituents of insoluble dietary
fiber, acting as a hydrophilic bulking agent for feces & potentially aiding in
defecation.
• It used as Diluent/binder in tablet (MCC-Micro crystalline cellulose)
• Cellulose acetate fibers used as wound dressing.
• Carboxylated MCC used as film coating agent.
Polysaccharides from plant source: Agar
• Agar is a mixture of two components polysaccharides agarose & agarpectin, It forms
the supporting structure in the cell walls of certain species of algae & is released on
boiling.
• Agar can be used as a laxative, an appetite suppressant, thickeners for soups, used in
fruit preserves, ice-cream. It is used as gelling agent.
10. Polysaccharides from Animal source: Chitin
• A long chain polymer of N-acetylglucosamine is a derivatives of glucose. It is a
primary component of cell wall in fungi, the exoskeletons of anthropoids such as
insects, mollusk, scales of fish.
• The structure of chitin was determined by Albert Hofmann in1929.
• It is a modified polysaccharide that contain nitrogen, It is synthesized from units of
N-acetyl-D-glucose mine. These units from covalent ß-(1-4) linkage (like the linkages
between Glucose units forming cellulose).
• Chitin may be described as cellulose with one hydroxyl group on each monomer
replaced with an acetyl amine group.
• In Agriculture, It is a good inducer of plant defense mechanisms for controlling
diseases. In Industry, It is used in food processing include the formation of edible
films & as an additive to thicken & stabilize foods.
11. Polysaccharides from Animal source: Xanthan Gum
• Source: Product of gram negative bacteria Xanthomonas Campestris
• Cellulose derivative contain a cellulose backbone (-D-glucose residue) & a
triasaccharide side chain of -D-mannose, -D-gluronic acid.
• Application: Oral & topical formulations, cosmetics, food industry as a suspending
and stabilizing agent.
Polysaccharides from Animal source: Alginate
Source: Alginate is a water-soluble linear polysaccharide extracted from brown seaweed
It is used as dietary supplements, used as thickener, moisturizer in cosmetic product.
12. Proteins from Animal source: Collagen
• Source: Primary protein component of animal connective tissues. e.g. pig skin, bovine
hide, pork & cattle bones.
• 27 types of collagen exist & is composed of different polypeptide, (glycine, proline,
hydroxylproline & lysine)
• Application: Collagen films- ophthalmology DDS for slow release of drug. Tissue
engineering- skin replacement, bone substitutes & artificial blood vessels & valves.
Proteins from Animal source: Gelatin
• Properties: Translucent, colorless, A high molecular weight polypeptide. It consists of
19 amino acids, water soluble.
• It is used in tablet coating, capsule shell preparation, microencapsulation,
nanoparticles & microparticles.
13. Proteins from Plant (Vegetable) source: Wheat Gluten
• Source: Product of the starch fabrication.
• Advantages: Fastest degradation rates, biodegradable, non-toxic, available in high
quality & low cost.
• Application: Film forming agent.
Proteins from Plant (Vegetable) source: Soy protein
• Soy protein isolated from soya beans
• Health benefits: Helps in heart problems.
