Final answer:
Thermosoftening polymers, or thermoplastics, soften and can be reshaped when heated, while thermosetting polymers form permanent structures upon heating that do not melt but decompose if reheated excessively.
Step-by-step explanation:
The main difference between thermosoftening polymers and thermosetting polymers lies in their behavior upon heating and their molecular structure. Thermoplastics, or thermosoftening polymers, soften when heated and can be remolded multiple times without altering their chemical structure. They have linear or branched structures that allow them to become flexible and deformable at certain temperatures, known as the glass transition temperature. Common examples include materials like polyethylene and polystyrene.
Conversely, thermosets are polymers that form permanent bonds when cured and will not soften upon reheating. They have a highly cross-linked structure, which prohibits them from melting, and instead, they will decompose if heated excessively. Bakelite, an early synthetic resin used in a variety of applications, is an example of a thermosetting polymer. Because of their structural differences, thermosets are ideal for high-heat and high-stress applications where a durable, permanent shape is essential.