Which material is defined as having the ability to return to its original shape after being stretched to twice its size?

The correct answer is elastomer. This material is characterized by its remarkable elasticity, which allows it to be stretched significantly—up to twice its size or more—and return to its original shape once the tension is released. This unique property is due to the molecular structure of elastomers, which consist of long-chain polymers that can move and realign under stress, providing resilience and flexibility.

Elastomers are commonly used in various roofing applications, particularly in membranes where stretchability and recovery are essential to maintaining a waterproof seal while accommodating movement caused by temperature changes or structural settling. Their performance is crucial for preventing leaks and ensuring the longevity of roofing systems.

Other materials mentioned, such as thermoplastics and fiberglass, do not possess the same level of elasticity. Thermoplastics can be reshaped upon heating but do not stretch in the same way elastomers do. Fiberglass has strength and rigidity but lacks the ability to stretch or return to form, making it unsuitable for applications that require high deformation and recovery. Polyurethane can be formulated as either a rigid or flexible material; while some polyurethanes can exhibit elastic properties, they are not universally defined by the same characteristics as elastomers. Thus, the definition aligns closely with the properties of elastomers, confirming