The versatility of PA has made it one of the most widely used thermoplastic materials in engineering applications. They are characterized by excellent mechanical properties that make them both rigid and tough, like PA66, and soft and flexible, like PA12. They also have anti-friction properties and can absorb moisture; from Bausano’s point of view and experience this last characteristic should be carefully considered, depending on the final application, as it can negatively affect the properties and dimensional stability of the finished product.
The properties of polyamides depend mainly on the concentration of the polar amide groups, which correlates with the length of the aliphatic chains interconnecting them. Each type of PA is identified by a number representing its molecular structure and defining its different properties.
In general, aliphatic polyamides (PA) are semi-crystalline thermoplastics with low density and high thermal stability. Due to their extraordinary wear, heat and impact resistance as well as their good friction coefficient, they are among the most important and widely used engineering thermoplastics for mechanical applications.
To sum up, polyamides generally offer:
- High abrasion resistance
- High thermal stability
- Very good mechanical resistance and hardness
- High mechanical damping characteristics
- Good sliding properties
- Good chemical resistance
These characteristics make it a suitable polymer to replace metal in applications requiring strength, toughness and, above all, low weight. It has therefore found wide application, also for Bausano extruders, in the automotive and industrial sectors.
As already mentioned, and as is also true for other polymers, the characteristics can vary considerably depending on the chemical structure and on the use of different types of fillers. One can distinguish polyamides with molybdenum disulphide additives, which help to decrease the friction coefficient and increase the stiffness of the material, while those with glass fibers additives help to considerably increase (up to four times) the value of the elastic modulus and the dimensional stability.
In view of this, Bausano has a long experience in designing and building specific extruders not only based on the material to be processed but also in relation to the type of filler.
We have talked about this topic in detail here in this article about screw wear