Polyamides are thermoplastic materials. There are different typologies belonging to the polyamide range, popularly known as ‘nylon’. The most important are: PA 6, PA 66, pure and changed, extruded and poured, PA 11 and PA 12. These show different physical properties, mainly determined by their composition and by the structure of the molecular chain.
In particular, PA 6 is a semi-crystalline polymer. This is a widespread material which has excellent features.
- High shock resistance, also at low temperatures
- Low friction coefficient
- High power attenuation
- A good resistance to aging, atmospheric agents, oils and machine greases
- In compliance with current regulations to be used in contact with foods
- Suitable up to 90 °C
- If it is used in a dried form, it appears to be breakable
- If it is moisturised, it appears to be malleable and shock resistant
- It is non-resistant to concentrated acids
SOME FIELDS OF APPLICATION
- Mechanical industry for bearings, gearings, shock absorbers, wheels, supports, pulleys
- It is used in the food industry.
REINFORCEMENTS AND CHARGES
Owing to the fact that PAs soften at high temperatures, a lot of them are available in strengthened formulations with a maximum 50% of glass fibres, carbon or others, which increase the resistance, the module and the heat stability.
- Silicon dioxide, talc, gypsum and glass beads increase the stiffness and reduce the shrinkage and deformation tendency. These formulations have become particularly important for the production of technical parts.
- The PA 6 at a 1-2% volume of PA-Clay nanocomposites shows an oxygen permeability reduced to 50%, that it is to say a nearly unnoticeable reduction in the puncture resistance.
- The metallic powders, such as aluminium, copper, bronze, iron, zinc or nickel increase the heat stability and allow the production of electrical conductors.
- Magnets are produced by a charge at 80% of barium-ferrite.
- The sliding wear behaviour has been improved by the addition of MoS2, PTFE, PE-HD and graphite.