A Powerpoint presentation on the topic polymer chemistry

Learning material

1. POLYMER CHEMISTRY SUBMITTED BY AMRUTHA G NAIR PHYSICAL SCIENCE CPAS, CTE, VAIKOM

2. Polymer chemistry is the study of the synthesis, characterization and properties of polymer molecules or macromolecules, which are large molecules composed of repeating chemical subunits known as monomers. POLYMER CHEMISTRY

3. POLYMER MONOMER A polymer is a large molecule made up of many repeating structural units, or monomers.  The word "polymer" comes from the Greek words poly, meaning "many", and mer , meaning "parts". Examples : nylon, polyethylene, DNA, cellulose , etc A monomer is a molecule or small group of atoms that can bond with other monomers to form a larger structure called a polymer.  The word "monomer" comes from the words "mono-" meaning "one" and "-mer" meaning "part". Examples :  Glucose, vinyl chloride, amino acids, etc

4. The process of formation of polymers from respective monomers is called polymerization. Degree of polymerization The term  degree of polymerization  refers to the number of repeating units in the polymer molecule. POLYMERIZATION

5. Natural polymers These polymers are found in plants and animals. Examples are proteins, cellulose, starch, some resins and rubber. Synthetic polymers These are man-made polymers extensively used in daily life as well as in industry. Examples are plastic (polythene), synthetic fibers (nylon 6,6) and synthetic rubbers (Buna - S) are Classification of Polymers One of the common classifications of polymers is based on source from which polymer is derived.

6. TYPES OF POLYMERISATION Addition Polymerization Condensation Polymerization Addition polymerization, also known as chain-growth polymerization, is  a chemical reaction that creates polymers from monomers without the loss of small molecules . Condensation polymerization is a chemical reaction that joins smaller molecules, or monomers, to form larger polymers.  This process typically involves the loss of a small byproduct, such as water or ammonia .

7. Mechanism of Addition Polymerisation Step 1 : Initiation Formation of Free Radicals : Initiators (like peroxides) decompose to generate free radicals. Activation of Monomers : The free radicals react with the unsaturated bonds of monomers, creating a reactive species called a propagating radical . Mechanism of Polymerisation Reactions

8. Step 2 : Propagation Chain Growth : The propagating radical attacks another monomer, adding it to the growing chain and forming a new radical. Repeat : This process continues, with the radical at the end of the chain reacting with more monomers, resulting in a long polymer chain. Step 3 : Termination Radical Combination : Two growing radical chains can combine to form a stable molecule, effectively terminating the reaction. Disproportionation : A radical can transfer a hydrogen atom to another radical, forming a stable product and terminating both chains.

9. Step 1 : Activation of Monomers Monomers with functional groups (like -OH, -NH₂, or -COOH) are activated. For example, a diol (with two -OH groups) and a diacid (with two -COOH groups) can be used. Step 2 : Stepwise Reaction Formation of Dimers : The functional groups react, forming a dimer and releasing a small molecule (usually water) This step can be repeated, leading to longer chains (oligomers) or polymers. Mechanism of Condensation Polymerisation

10. Step 3 : Propagation The process continues, with more monomers reacting with existing oligomers or polymers, leading to the growth of the polymer chain while continuously releasing small molecules . Step 4 : Termination The reaction can terminate when no more functional groups are available for reaction, or when a specific length of the polymer is reached. The final polymer typically has functional groups at its ends.

11. Copolymerization is a polymerization reaction in which a mixture of more than one monomeric species is allowed to polymerize and form a copolymer. The copolymer can be made not only by chain growth polymerization but by step growth polymerization also. It contains multiple units of each monomer used in the same polymeric chain. Examples include polyethylene-vinyl acetate (PEVA), nitrile rubber, and acrylonitrile butadiene styrene (ABS ). Copolymerization

12. Polymers that break down into natural substances (water, carbon dioxide, biomass) through biological processes . Properties : Varying mechanical and thermal properties Designed to decompose in specific timeframes Applications : Packaging: Biodegradable bags and films Agriculture: Mulch films and seed coatings Medical: Sutures and drug delivery systems Biodegradable Polymers

13. Environmental Impact : Reduces plastic waste and pollution Requires proper disposal and composting for effective biodegradation

14. Types of Biodegradable Polymers Natural Polymers: Synthetic Polymers: Starch Cellulose Chitosan Polylactic Acid (PLA) Polyhydroxyalkanoates (PHA) Polycaprolactone (PCL)

15. https://ncert.nic.in/textbook/pdf/lech206.pdf https:// www.sciencedirect.com/topics/materials-science/biodegradable-polymer Reference:

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