Man-Made Materials
Chemistry · मानव निर्मित सामग्री
📋Quick Overview
Polymers are large molecules made by joining many small molecules (monomers). Plastics, rubber, and synthetic fibres are all polymers. Plastics are classified as Thermoplastics (can be remoulded on heating) and Thermosetting plastics (cannot be remoulded). Synthetic fibres like Nylon, Polyester, Rayon, and Acrylic have largely replaced natural fibres in many uses.
📖Thermoplastic vs Thermosetting Plastic
📖Synthetic Fibres
| Fibre | Made From | Properties | Uses |
|---|---|---|---|
| Rayon (Artificial Silk) | Wood pulp / cellulose | Absorbs moisture, cheap silk substitute | Clothing, bedsheets, carpets |
| Nylon | Coal, water, air (first fully synthetic fibre, 1935) | Very strong, elastic, lustrous, dries quickly | Ropes, stockings, toothbrush, parachutes |
| Polyester (Terylene/PET) | Ethylene glycol + Terephthalic acid | Wrinkle-free, does not absorb moisture, durable | Clothes, PET bottles, sails, conveyor belts |
| Acrylic (Orlon) | Acrylonitrile | Wool-like, lightweight, warm | Sweaters, blankets, shawls (substitute for wool) |
📖Important Plastics
| Plastic | Type | Uses |
|---|---|---|
| Polythene | Thermoplastic | Carry bags, packaging, bottles |
| PVC (Polyvinyl Chloride) | Thermoplastic | Pipes, insulation, flooring |
| PET (Polyethylene Terephthalate) | Thermoplastic | Water/soft drink bottles |
| Teflon (PTFE) | Thermoplastic | Non-stick cookware (no friction) |
| Bakelite | Thermosetting | Electrical switches, handles (heat resistant) |
| Melamine | Thermosetting | Fire-resistant, kitchen utensils, floor tiles |