Polymer Science

 Introduction  Classification of Polymer  Polymerization & It’s types  Characteristics of Polymer  Application of Polymer

 A word polymer is a combination of two greek word “poly” means “many” and “meros” meaning “parts of unit”.  A polymer is a large molecule of which is formed by repeated linking of the small molecules called “monomers”.  Example: Polyethylene

1. Based on source 2. Based on structure 3. Based on polymerization 4. Based on thermal properties

1) Natural polymer: Example: Proteins, Cellulose, Starch, Rubber 2) Semi synthetic polymer: Example: Cellulose derivatives – cellulose acetate (rayon), Cellulose nitrate, Methyle cellulose 3) Synthetic Polymer: Example: Polyethylene, Polystyrene, Nylon

1) Linear Polymer : Consist of long & straight chains. 2) Branched Polymer: Contain linear chain having some branches. 3) Cross Linked Polymer: A polymer that includes interconnection between chains. 4) Network Polymer: A cross linked polymer that includes numerous interconnections between chain.

Structure:

1) Addition Polymer: Example: polyethylene, polypropylene, PVC 2) Condensation Polymer: Example: Nylon 6,6, Nylon 6

1) Thermoplastics: Example: Polyethylene, Polystyrene 2) Thermo sets: Example: Bekelite

Definition: In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three- dimensional networks.polymer chemistrymonomer moleculeschemical reactionpolymer

 Addition Polymerization  Condensation Polymerization

 In this polymerization many monomers bond together via rearrangement of bonds without the loss of any atom or molecule under specific condition of heat, pressure, catalyst. monomers  It is also known as chain growth polymerization.  Example:

 In this polymerization involves 2 monomers that have different functional group with losing small molecules as byproducts such as water or methanol.  It is also known as step growth polymerization.  Example:

 Low density  Good corrosion resistance  Good mould ability  Excellent surface can be obtained  Economical  poor tensile strength  low mechanical properties  Poor temperature resistance  Can be produced transparent in different colour.

 Polymeric materials are used in and on soil improve aeration provide much and promote plant growth and health Medicine:  Many biomaterials especially heart valve replacement and blood vessels are made of polymer like Dacron, Teflon and Polyurethane. Consumer Science:  Plastic containers of all shapes and size are light weight and economically less expensive then the more traditional containers, clothing, floor coverings, garbage disposal bags and packaging are other polymer applications.

Industry:  Automobile parts, windshields for fighter planes, pipes, tanks, packing materials, insulation, wood substitutes, adhesives, matrix for composites and elastomers are all polymer applications used in the industrial market. Sports:  Playground equipment, various balls, golf clubs, swimming pools and protective helmets are often produce from polymers.

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