Polymer Types and their General Properties
May 20th, 1986
Lecture to the National Centre of Tribology’s seminar on Non-Metallic Bearings in Engineering, Risley.
S F Bush
Introduction to Polymeric Materials
- All materials can be seen as assemblies of atoms held together by electrical forces usually described as bonds.
- In metals, the bonds are not particularly directional which accounts both for the variety of crystal structures and the relatively close packing giving their characteristic high densities.
- The bonds between atoms in polymers on the other hand are decidedly directional, forming in the simplest cases chains of atoms which thread their way more or less randomly around their neighbour chains.
- Basically, the forces binding atoms together along a polymer chain are very large (and comparable with the typical metal bond) while the forces between chains are one to two orders of magnitude smaller.
- Figure 1 is a two dimensional visualisation of a random assembly of polymer chains in the solid or liquid states.