Chemistry That Does Work
Materials & Corrosion
13 minStudent plan
Polymers, alloys and the electrochemistry that quietly destroys metal structures from the inside.
After this lesson you can
- Choose between a thermoplastic, a thermoset and an elastomer
- Say what alloying buys you and what it does not
- Explain why aluminium survives and steel rusts through
Polymers
A polymer is a long chain of repeating units. Polythene is thousands of ethene molecules joined end to end, and the properties come as much from the arrangement of the chains as from the chemistry.
Thermoplastics, polythene, PET, nylon, PLA, have separate chains held by weak forces, so they soften on heating and can be remelted. That is what makes them injection mouldable and 3D printable, and also why a printed part deforms in a hot car.
Thermosets, epoxy, vulcanised rubber, phenolic, have chains chemically cross-linked into one network. They do not remelt; heated far enough they char. That is why epoxy holds under heat and why a thermoset cannot be recycled by melting.
In the full lesson
- Polymers
- Alloys
- Corrosion
This lesson comes with the Student plan. The first module of Chemistry is free.