Free of colour and odour gas, made e.g. from, Naphtha (petroleum) by cracking or from bio-ethanol by dehydration, Molecules that are linked by polymerization to form chains of molecules and then plastics. More of the A polymer is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. polyethylene (Polyethylene, thermoplastic polymerised from ethylene. Can be made from renewable resources (sugar cane via bio-ethanol). [bM 05/10] More).