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प्रश्न
Distinguish between
Thermoplastic and thermosetting plastic.
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उत्तर
| Thermoplastic polymers | Thermosetting polymers |
| These are formed by addition polymerisation | These are formed by condensation polymerization |
| Generally more expensive than thermosetting | Cost-effective |
| Monomer used in these is generally bifunctional | In this monomer used is tri, tetra or polyfunctional |
| Aesthetically-superior finishes | More difficult to surface finish |
| They are long-chain linear polymer with negligible cross-links | These have three-dimensional network structure with number of cross-links |
| less resistant to high temperatures | More resistant to high temperatures than thermoplastics |
| They have low molecular wt. | They have high molecular wt. |
| They are soft, weak, brittle | They are hard, strong and more brittle |
| Highly recyclable | Cannot be recycled |
| They can be softened and reshaped and reused. | They cannot be softened and reshaped again once again. Highly flexible design |
| High-impact resistance | Low-impact resistance |
| Remoulding/reshaping capabilities | Cannot be remoulded or reshaped |
| Eco-friendly manufacturing | Eco-foe manufacturing |
| e.g.- polyethene, polystyrene, PVC, PVA etc. | e.g.- phenol-formaldehyde, ureaformaldehyde, nylon 6 : 6 etc. |
संबंधित प्रश्न
Should the handle and bristles of a tooth brush be made of the same material? Explain your answer.
Motor cars are coated with ______.
Who is my partner?
| 'A' column | 'B' column |
| a. Lead glass | i. Plates |
| b. Bakelite | ii. Mattresses |
| c. Thermocol | iii. Electric bulb |
| d. Optic glass | iv. Electric switch |
| e. Polypropylene | v. Lens |
Explain the effect of following materials on environment and human health.
1. Plastic
2. Glass
3.Thermocol.
Can you replace the following packaging material with those which can be recycled or reused.
Glass tumblers packed in thermocol box.
Why should we be careful in using plastic bags to store cooked food items?
True or False
A lot of plastic pollutes our environment.
A plastic bag dumped in the soil stays without breaking down for 500 years. If a new generation starts in every 30 years, how many generations would it take to see the plastic bag finally broken down?
PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Can you write the major difference between these two types of plastics?
Which of the following is non–bio degradable?
