Thermoplastic: Thermoplastic is a polymer and it is melted when the heat is given to it. example: polyethylene
Thermosetting: Thermosetting is also a type of polymer and it is generally unaffected by the heat. Once a thermosetting polymer is formed it can not be reshaped. example: silicon, polyurethane.
PVC: The full name of PVC is polyvinylchloride.
PVC is a type of thermoplastic. It is high strength polymer used in pipe and medical machines as well.