A thermoplastic is a material which becomes soft when heated and hard when cooled. Thermoplastic materials can be cooled and heated several times. They can be recycled. When thermoplastics are heated, they melt to a liquid. They also freeze to a glassy state when cooled enough.
Thermoplastic can be moulded into any shape. Thermoplastics differ from thermosetting polymers. Thermosets form irreversible chemical bonds during the curing process.