Final answer:
To distinguish between a thermoplastic and a thermoset, observe the material's response to heat; thermoplastics can be remolded upon reheating, whereas thermosets permanently harden and decompose upon reheating.
Step-by-step explanation:
To determine whether a part is made of a thermoplastic or a thermoset, you can look at how the material responds to heat. Thermoplastics soften when heated, which allows them to be remolded and reshaped multiple times. Common examples include polyethylene and polystyrene. In contrast, thermosets harden permanently after being heated and shaped once; upon reheating, instead of softening, they decompose. A classic example of a thermoset is Bakelite, which can be found in items like pot handles and electrical outlets.
Other identifying characteristics include the glass transition temperature (Tg) for thermoplastics, which is a specific temperature at which the material becomes more flexible and deformable. In medical uses, polyethylene variants like LDPE and HDPE are recognized for their flexibility and strength, respectively, which can also be an indication of their classification. An understanding of polymer crystallinity and cross-linking is useful in differentiating between the two types, as thermosetting polymers are highly cross-linked and do not display a melting point like thermoplastics do.
To determine whether a part is made of a thermoplastic or a thermoset, you can observe its behavior when heated. Thermoplastics soften when heated and can be molded into different shapes. They can be reheated and reformed multiple times. Thermosets, on the other hand, harden permanently when heated and cannot be reshaped. They will decompose if reheated. For example, Bakelite is a thermoset plastic used in toasters, handles for pots and pans, and electrical outlets.