Plastics are typically carbon based. Carbon atoms are connected to other elements and when the connection of other elements with carbon results in long chains, the plastic is a thermoplastic. Any plastic that can be melted is a thermoplastic.
Often, additives are put into a plastic mixture. These additives may include lubricants, antimicrobials, antioxidants or flame retardants. These additives give the plastic a specific property and can protect the plastic from water or heat damage and make it resistant to bacteria.Learn more about Chemistry