Introduction

Polymers are high molecular weight macromolecules composed of repeating structural units (monomers) bonded together through covalent bonds. They play a vital role in daily life and industrial applications, including plastics, rubber, fibers, and biomedical materials. Understanding polymers is crucial for NEET aspirants.

Classification of Polymers

1. Based on Source

• Natural Polymers – Found in nature (e.g., proteins, cellulose, rubber).
• Semi-Synthetic Polymers – Modified natural polymers (e.g., cellulose acetate, rayon).
• Synthetic Polymers – Man-made polymers (e.g., PVC, Nylon).

2. Based on Structure

• Linear Polymers – Long, straight chains (e.g., PVC, polyethylene).
• Branched Polymers – Have side chains (e.g., Low-density polyethylene).
• Cross-linked Polymers – Have covalent cross-links (e.g., Bakelite, rubber).

3. Based on Polymerization Process

• Addition Polymers – Formed by repeated addition of monomers (e.g., Polyethylene).
• Condensation Polymers – Formed by elimination of small molecules (e.g., Nylon-6,6, Polyester).

Polymerization

1. Addition Polymerization

Involves repeated addition of monomers with double/triple bonds. Examples:

• Polyethylene (PE) – Used in packaging.
• Polystyrene – Used in insulation materials.

2. Condensation Polymerization

Involves elimination of small molecules (e.g., water, HCl). Examples:

• Nylon-6,6 – Used in textiles and ropes.
• Terylene (Polyester) – Used in fabric production.

Biodegradable and Non-Biodegradable Polymers

• Biodegradable Polymers – Break down naturally (e.g., Polyhydroxybutyrate (PHB)).
• Non-Biodegradable Polymers – Do not decompose easily (e.g., PVC, polystyrene).

Applications of Polymers

• Plastics – Used in packaging and household items.
• Fibers – Used in textiles (e.g., Nylon, Polyester).
• Rubber – Used in tires and footwear.

Conclusion

Polymers are essential materials in modern life, with wide applications in industries, medicine, and technology. Understanding their classification, polymerization, and uses is important for NEET preparation.