This site will briefly touch on the use of thermoset material, but due to its cost it is used sparingly in the disposable plastic industry . The nature of thermoplastic does not allow for it to be remelted and reused. Its structure once molded is set due to a chemical reaction called cross linking in the molecules
In the thermoplastic applications this cross linking does not occur in the pure sense of the concept of thermoplastic behavior. That has now changes on so we now have some plastic that has a small amount of cross linking in thermoset rubber applications. These applications are now call Thermo Plastic Rubber, TPR for short..
To understand the differences between Thermoplastic and thermoset think of how you would boil and egg and how after it is boiled it can not be returned to its original state. This is the same thing that occurs with thermoset material, it can not return to it original liquid state. In contrast a thermoplastic material can be compared to butter which can be reheated and cooled to change its shape. So the real difference is how the thermoset material responds to energy to change its shape. Once it is set it is set...