The question asks about a polymer that can be stretched and then returns to its original state once the force is removed. This property is known as elasticity, a key feature of elastomers. Let's examine the given options:
Bakelite: Bakelite is a thermosetting plastic known for its rigidity and resistance to heat and chemicals. It does not have elastic properties and does not return to its original shape when deformed.
Nylon 6, 6: Nylon 6, 6 is a type of polyamide, which is strong and resistant to abrasion, but it is not elastic like a rubber. It is commonly used for manufacturing textiles and engineering thermoplastics, but it doesn’t exhibit rubber-like elasticity.
Buna-N: Buna-N, also known as Nitrile rubber, is a synthetic rubber copolymer of acrylonitrile (ACN) and butadiene. It is known for its excellent elasticity, which allows it to be stretched and then revert to its original shape once the force is removed. This ability to stretch and recover is characteristic of elastomeric materials.
Terylene: Terylene is a type of polyester, primarily used in textiles. It is valued for its strength and durability, but it lacks the elastic properties necessary to return to its original shape after being stretched.
Given this analysis, Buna-N is the correct answer because it is an elastomer, capable of being stretched and then returning to its original state, demonstrating significant elasticity.
