3. INTRODUCTION
• Definition :
Apolymer is a large molecule (macromolecule)
composed of repeating structural unit connected by covalent
chemical bonds.
- The word is derived from the Greek words (poly), meaning
"many"; and (meros), meaning "part"
Example:- Butadiene ,poly-vinyl-chloride etc.
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4. Types Of Linking In Polymers
• Linear Polymers:
Apolymer in which the molecules form long
chains without branches or cross-linked
structures.
examples: nylon, polyester, PVC etc.
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5. • Branched Polymer:
Apolymer chain having branch points that
connect three or more chain segments.
Examples: polythene, glycogen, starch etc
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6. • Cross linked Polymer:
. Cross-links are bonds that link one polymer chain
to another. They can be covalent bonds or ionic
bonds.
Examples: malamine formaldehyde resin etc
• Cross linked Polymer are know as thermosetting materials.
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7. classification of polymer
(According to their properties & characteristics.)
1) Natural and Synthetic Polymers.
2)Organic and Inorganic Polymers.
3)Thermoplastic and Thermosetting Polymers.
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9. 2) Organic and Inorganic Polymers:
• A Polymer whose backbone chain is essentially made of carbon
atoms is termed an Organic polymer.
Examples- cellulose, proteins, polyethylene, nylons.
• A Polymer which does not have carbon atom in their
backbone chain is termed as Inorganic polymer.
Examples- Glass and silicone rubber
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10. 3) Thermoplastic and Thermosetting Polymer:
• Some polymer are soften on heating and can be converted into
any
shape that they can retain on cooling.
• Such polymer that soften on heating and stiffen on cooling are
termed as `thermoplastic’ polymers.
Ex. Polyethylene, PVC, nylon, sealing wax.
• Polymer that become an infusible and insoluble mass on
heating are called ‘thermosetting’ polymers.
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11. • Molecular weight determination
• There are two ways to calculate the
average molecular weight:
1. Number Average Molecular Weight
2. Weight Average Molecular Weight
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12. • Molecular weight determination
1. Number Average Molecular Weight
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Divide the total number of the sample
by the total number of the molecule
13. • Molecular weight determination
2. Weight Average Molecular Weight
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Summing the weights of all the
chains and then dividing by total
number of chain
14. BIO DEGRADABLE POLYMER
• Biodegradable polymers can be classified in two:
• Natural biodegradable polymer
examples: xanthum gum, gaur gum, chitosan, chtin etc.
2. Synthetic biodegradable polymer
examples: Polyanhydrides, Poly( latic acid ) etc.
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15. Conclusion
Polymers are long chain
molecules with properties
dominated by their chain
behaviour and the nature of
their chemical make-up or
constitution
