polymer

• Low density poly(ethene), LDPE - Flexible, unreactive, can be made into films
• High density poly(ethene), HDPE - Strong, flexible, resists shattering, resists chemical attack
• Thermosoftening plastics melt when they are heated. Most plastics that we come across in everyday life are thermosoftening plastics. This means that they can be recycled, which involves melting them before making a new product.
• Thermosoftening plastics do not have covalent bonds between neighbouring polymer molecules, so the molecules can move over each other when heated and the plastic melts.
• Thermosetting plastics do not melt when heated. tend to char and burn when heated, but they are resistant to much higher temperatures than thermosoftening plastics.