Differentiate between thermoplastics, thermosetting plastics and elastomers

Thermoplastics, thermosetting plastics, and elastomers are all types of polymers, but they have different properties and uses.

1. Thermoplastics: These are polymers that become pliable or moldable above a specific temperature and solidify upon cooling. The process is reversible, meaning they can be reheated, reshaped, and frozen repeatedly. This property makes thermoplastics recyclable. Examples of thermoplastics include polyethylene, polypropylene, PVC, and polystyrene.

2. Thermosetting Plastics: Unlike thermoplastics, thermosetting plastics can only be heated and shaped once. After they have solidified, they stay solid and cannot be remelted or reshaped upon reheating. This is because during the initial heating, a chemical reaction occurs that creates cross-links between the polymer chains, making the structure rigid. Examples of thermosetting plastics include vulcanized rubber, Bakelite, and polyurethanes.

3. Elastomers: These are a type of polymer with very high elasticity, meaning they can be stretched to a large degree and still return to their original shape when the stress is released. They are amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible. Elastomers are often thermosets but may also be thermoplastic. The long polymer chains cross-link during curing, i.e., vulcanizing. The molecular structure of elastomers can be imagined as a 'spaghetti and meatball' structure, with the meatballs signifying cross-links. Examples of elastomers include natural rubber, neoprene, and silicone.

Thermoplastics, thermosetting plastics, and elastomers are all types of polymers, but they have different properties and uses.

1. Thermoplastics: These are a type of plastic made from polymer resins that become liquid when heated. They can be heated, cooled, and reshaped repeatedly without significant damage. This makes them very versatile and they are used in a wide range of applications, from packaging and bottles to automotive parts and medical devices. Examples of thermoplastics include polyethylene, polypropylene, PVC, and polystyrene.

2. Thermosetting Plastics: Unlike thermoplastics, thermosetting plastics can only be heated and shaped once. After they have been heated and formed into a shape, they become rigid and cannot be reshaped again. This is because the polymer chains form strong cross-links with each other during the curing process. Thermosetting plastics are used in applications where heat resistance is required, such as in the manufacture of electronics and appliances. Examples of thermosetting plastics include epoxy, melamine, and phenolic resins.

3. Elastomers: These are a type of polymer with very high elasticity, meaning they can be stretched or deformed and return to their original shape. Elastomers are also known as rubbers. They are used in a variety of applications, including tires, belts, hoses, and gaskets. Examples of elastomers include natural rubber, neoprene, and silicone rubber.