A plastic material that softens or flows when reheated is known as what type of plastic?

A plastic material that softens or flows when reheated is classified as a thermoplastic. This type of plastic can be molded, shaped, and remolded multiple times upon heating without a significant change in its chemical structure. The ability to soften upon reheating makes thermoplastics highly versatile for various applications, allowing them to be processed using techniques such as injection molding, extrusion, and blow molding.

In contrast, thermosetting plastics undergo a chemical change when heated, resulting in a rigid structure that does not melt or flow upon subsequent heating. This property makes thermosetting plastics suitable for applications requiring durability and thermal stability but limits their reshaping capability. Elastomers, on the other hand, are a class of polymers known for their elasticity, allowing them to return to their original shape after stretching, but they do not fall under the category of plastics that can be remolded upon heating as thermoplastics can. Composites, while useful in combining materials to enhance performance, also do not reflect the specific behavior of softening or flowing upon reheating. Thus, thermoplastic is the definitive classification for the described material behavior.