POLYMERS

Mayurbhanj School of Engineering

Department – Science and Humanities

Prepared by – Mamata Mohanta

( Lect. In Chemistry)

CONTENTS

• Introduction
• Types of Polymer
• Classification of Polymer
• Characteristics of Polymer
• Application
• Referance

INTRODUCTION

• Polymers are very large molecules made when hundreds of monomers join together to form long chains.
• The word POLYMER comes from the Greek word poly means many and Mer means parts.
• Polymer is used as a synonym for plastic.
• All plastics are polymers, but not all polymers are plastics

N(CH2-CH2)----------🡪(-CH2-CH2-)S

Ethylene Polyethylene

TYPES OF POLYMER

• Natural Polymers
• Homopolymer
• Copolymer
• Thermoplastics
• Thermosets
• Long chain Polymers

NATURAL POLYMERS

• Definition: Natural polymer is a polymer that results from only raw materials that are found in nature.
• Some of these natural polymers include DNA and RNA.
• Cotton, DNA, wool, are some of the naturally occurring polymers.

HOMOPOLYMER

• Homopolymers are synthesized from a single type of monomer.
• Homopolymers are consists of chains with identical bonding linkages to each monomer unit.
• This usually implies that the polymer is made from all identical monomer molecules.

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COPOLYMER

• When two or more different monomers together to polymerize their results is called as copolymer.
• This process is called as copolymer.
• Types of Copolymer:
• Statistical copolymer
• Alternating copolymer
• Block copolymer
• Graft copolymer

THERMOPLASTIC

• A type of plastic that can be softened by heat, hardened by cooling , and then softened by heat over and over again.
• Thermoplastic are not cross- linked polymer.
• Examples: Polyethylene, Nylon, Polyvinyl chloride.

THERMOSETS

• Thermoset having the property of becoming permanently hard and rigid when heated.
• Thermosets are hard and rigid at room temperature and do not soften on heating.
• Examples: Epoxy resins, Phenolic resins, Unsaturated polyester resins.

LONG CHAIN POLYMERS

• A very long strand of repeating molecules linked together by primary bond.
• Polymer chains are orient themselves in lines as they enter a mold but may be annealed so they can recoil.

CLASSIFICATION OF POLYMER

BASED ON ORIGIN OF SOURCE

• Natural Polymer :- Polymers which are isolated from natural materials are called as Natural Polymers. E.g. : Cotton, silk, wool, rubber.
• Synthetic Polymer:- Polymers which are synthesized from low molecular weight compounds are called as Synthetic Polymers. E.g. : Polyethylene, nylon, terylene.
• Semisynthetic Polymers :- These polymers are mostly derived from naturally occurring polymers by chemical medication. E.g. : Rayon

BASED ON STRUCTURE

• Linear Polymer: Molecules form long chains without branches.
• Branched Polymer: Molecules having branch points that connects 3 or more segments.
• Cross-Linked Polymer: It includes interconnections between chains.
• Network Polymer: A cross linked polymer that includes numerous interconnections between chains.

BASED ON MODE OF POLYMERISATION

• Additional Polymerization:
• Same kind of monomers are straight forwardly added.
• It is rapid chain reaction having chemically activated mers.
• Each reaction sets up the condition for another to proceed.
• It consists of 3 stages:

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CHARACTERISTICS OF POLYMER

1. Low density
2. Low coefficient of friction
3. Good corrosion resistance
4. Good mould ability
5. Poor tensile strength
6. Low mechanical properties
7. Poor temperature resistance
8. Can be produced transparent or different colours

APPLICATION

• Medicine: Many biomaterials especially heart value replacements and blood vessels are made up of polymers like Dacron, Teflon.
• Consumer Science: Plastic containers of all shapes and size are light weight and economically less expensive than more traditional containers.
• Sport: Playground equipment, golf clubs, swimming pools and protective helmets are produced from polymers.

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