Polyamide, abbreviated as PA, is better known as nylon and was originally developed for the production of nylon stockings. PA belongs to the thermoplastic and crystalline material group and is a synthetic polymer, meaning it is composed of multiple units, including dicarboxylic acid and diamine. This composition occurs through amide bonds, which is also the reason for its name – a synthetic polymer composed of amide bonds is thus named Polyamide.
Polyamides and their composition
The crystallinity of polyamides is around 35% in PA6, around 50% in PA66, and around 70% in PA46. These types of polyamide are determined by the number of carbon atoms between two nitrogen atoms that follow each other in the molecular chain. A designation with a single number, such as PA6, is used when the two segments are identical, and a designation with multiple numbers, such as PA66 and PA46, is used when the segments are different. The higher the crystallinity, the higher the melting temperature of the polyamides as well. The melting temperatures for the mentioned polyamides are respectively 225 °C, 265 °C, and up to 295 °C, and the processing temperature typically lies around 30 degrees. This means, among other things, that polyamide has great strength and rigidity, even at high temperatures. Additionally, polyamide is also highly resistant to wear and chemicals.
Use of polyamides
As mentioned, polyamide was originally developed for the production of nylon stockings, but it is still widely used in textile production. Today, however, it is also used for many other purposes, including the production of tents, parachutes, carpets, brushes, and safety harnesses, as these need to be durable and difficult to break. Many car parts located under the car’s hood are also made of polyamides due to their resistance to high temperatures, chemicals, and wear. Today, many metal parts are also replaced with polyamide parts due to their durability, lightweight, and often lower cost. Polyamide is also increasingly used to produce packaging films for foodstuffs due to its resistance to puncturing and its barrier properties against carbon dioxide and oxygen. Polyamides for this type of use are often combined with polyethylene, which has a high water vapor barrier.
Polyamide for manufacturing machine parts
Polyamide is also often used for manufacturing machine parts due to its strength and durability, which are important requirements for machine parts. The mechanical properties, such as impact and notch impact strength, also play a role along with polyamide’s wear resistance, even on dirty or rough surfaces. It is also often necessary to develop parts that are resistant to various chemicals and fats, which polyamide fulfills.
