Hint: For (A): Thermoplastic polymers are weaker and held together by weak van der Waals forces of attraction, whereas thermosetting polymers are stronger and connected by strong hydrogen bonding.
For (B): Teflon, also called polytetrafluoroethylene, is produced through the polymerization of a single type of monomer.
Complete step by step answer:
A) Polymers vary based on their mechanical properties such as toughness, elasticity, and tensile strength. These properties are influenced by their intermolecular forces, like hydrogen bonds and van der Waals forces, which hold the polymer chains together. Based on these intermolecular forces, polymers can be categorized into four types:
(1) Fibers
(2) Elastomers
(3) Thermoplastic polymers
(4) Thermosetting polymers
Now, let’s differentiate between thermoplastic and thermosetting plastics.
| Thermoplastic plastics |
Thermosetting plastics |
| 1)Such polymers or plastics are typically produced through addition polymerization. | 1) These plastics are generally created through condensation polymerization. |
| 2) They consist of linear or somewhat branched long-chain polymers. | 2) They are cross linked or heavily branched. |
| 3) They can be easily softened when heated and solidified upon cooling. | 3) It cannot be softened on heating. |
| 4) They are held together by Van der Waal forces of attraction. | 4) They are connected by strong hydrogen bonds. |
| 5) In nature, they are soft, weak, and less brittle. | 5) They are strong, rigid, and more brittle by nature. |
| 6) Their molecular weight is low. | 6) Their molecular weight is large. |
| 7) They are quite soluble in organic solvents. | 7) They are insoluble in organic solvents. |
| 8) They can be remoulded into desired shapes. | 8) They cannot be remoulded. |
| 9) Monomers used here do not have more than two reaction sites. | 9) Monomers used here have more than two reaction sites. |
| 10) Examples: polythene, polystyrene, polyvinyl, etc. | 10) Examples: bakelite, urea-formaldehyde resins, etc. |
B) Teflon:
- Teflon, commonly referred to as polytetrafluoroethylene, is a type of vinyl polymer.
- It is produced through the free radical polymerization of tetrafluoroethylene. Tetrafluoroethylene is subjected to heat along with a free radical or persulfate catalyst under high pressure to synthesize Teflon.
The overall reaction for its formation can be expressed as:
Hence its monomer is tetrafluoroethylene. Its structure is: CF2=CF2
- This polymer is chemically inert and resistant to corrosion from reactive agents. It has a melting point of 600 K, along with high strength, toughness, and self-lubricating properties at low temperatures. Teflon exhibits these characteristics because of the carbon-fluorine (C-F) bonds. It begins to depolymerize at temperatures exceeding 650−700 °C.
- Teflon is used in applications such as manufacturing oil seals, gaskets, non-stick coated cookware, production of carbon fiber composites, expansion joints, and more.
Note: For (A): Thermosetting polymers have cross-linked or three-dimensional structures, making them more resistant to temperature fluctuations, whereas thermoplastic polymers are linear and do not withstand temperature changes as effectively.
For (B): Despite Teflon being inert and stable, at temperatures exceeding 300 °C, the Teflon coatings on non-stick cookware begin to degrade, releasing toxic chemicals that, when inhaled, can lead to polymer fume fever or Teflon fever.