What are thermosoftening polymers known for?

Thermosoftening polymers are known for their ability to melt when heated. This characteristic allows them to be reshaped and molded multiple times without significant degradation of their chemical structure. When these polymers are heated, the intermolecular forces between the polymer chains weaken, causing the material to become pliable and enabling it to flow and take on new shapes.

This property makes thermosoftening polymers versatile for various applications, such as in manufacturing processes like injection molding or extrusion. Once cooled, they solidify again, maintaining the new shape until they are reheated.

The other characteristics described in the other options do not apply to thermosoftening polymers. For instance, rigid materials that do not melt upon heating and maintain their shape are typically thermosetting polymers, which undergo a chemical change during curing that makes them hard and inflexible. Additionally, thermosoftening polymers do not possess the strong crosslinks commonly found in thermosetting polymers, which contribute to their rigidity and inability to be reshaped after the initial setting process. Thus, the ability to melt upon heating is a defining feature that sets thermosoftening polymers apart.