Differences Between Polyamide And Nylon

Although polyamides and nylon are often referred to interchangeably, they're not actually the same thing. The term "polyamides" refers to a group of materials with different properties and molecular structures, making them suitable for different uses. Nylon belongs to a subcategory called aliphatic polyamides. It might seem confusing, but don't worry, we will take a deeper look into the comparison between polyamides and nylons and offer easy ways to identify each polymer. We will also look at their grades, break down their basic chemical structure, and list their mechanical properties.

 

1. What Are Polyamides?

Polyamides are synthetic or natural polymers. They are made up of amide groups that are repeated and interconnected by amide links. They have increased crystallinity, and thermal and chemical resistance due to the presence of hydrogen bonds. Polyamides generally have poor resistance to moisture absorption, but, on the upside, some have excellent tensile strength and impact resistance. Some examples of natural polyamides include wool, silk, collagen, and keratin. Synthetic polyamides can be broken down into three categories:

 

Aliphatic Polyamides

This category also includes many grades of nylon such as Nylon 6 and Nylon 6/6.

Aromatic Polyamides: Also known as aramids, this category is preferred by many Xometry users to create fibers such as Nomex (used in fire-resistant fabrics), and Kevlar (known for its use in the construction of bullet-resistant vests).

Semi-Aromatic Polyamides

These high-performance engineering polymers, also known as polyphthalamides or PPA, have impressive high-temperature properties. Some of these include Rislan or Zytel, which is a material Xometry offers with its quick-turn injection molding service.

 

The molecular structure of polyamides can vary greatly, i.e., aliphatic polyamides like Nylon are polymerized from monomers like caprolactam and hexamethylenediamine. Aromatic polyamides, on the other hand, are polymerized from para-phenylenediamine and terephthaloyl chloride.

Polyamides possess high tensile strength. Their name alone refers to a range of different materials, some of which can be woven into fibers, cast, or injection molded. Nylon 6, for example, is an aliphatic polyamide that has a tensile strength of about 40MPa. Kevlar 29 is an aromatic polyamide that has a tensile strength of 3600 MPa. This considerable difference is because of the huge range of materials in the polyamide group.

 

2.Uses of Polyamides

Depending on the subcategory of materials, each polyamide will have different uses and applications. Here are some examples:

· Kevlar: This is a popular material that is often woven into bullet-resistant vests and used to reinforce tires.

· Nomex: Due to its outstanding thermal resistance properties, Nomex is a go-to material for workwear and fire-resistant suits.

· Nylon: An extremely popular and equally versatile material, Nylon can be spun into a fiber and injection molded. Some examples of where Nylon might be used include gear wheels and rope. It is also one of the most commonly 3D printed materials at Xometry via our SLS and MJF processes which primarily utilize Nylon materials.

· Wool: Another favorite, wool is used in the production of clothing, furniture, carpets, and other household goods.

 

3.What is Nylon?

Nylon is a trade name that was given to a group of aliphatic polyamides by the chemical company DuPont. Due to its high tensile strength, tough nature, and wear resistance, it has become one of the most popular engineering thermoplastics today and a common choice among Xometry customers. Like other thermoplastics, Nylon can be melted and formed to make parts using high heat in processes like injection molding, extrusion, and 3D printing as shown in the below image.

 

There are various grades of nylon, some of which can be formed into fabrics. Not all grades share the same molecular structures and polymerization techniques. Nylon is typically considered an amorphous polymer, but it can have a degree of crystallinity. Aliphatic polyamides are more popular than aromatic and semi-aromatic polyamides, and the most common types of nylon are Nylon 6/6 and Nylon 6.

 

4.Composition and Uses of Nylon

Nylon is an aliphatic polyamide that can be made from various materials and chemistries. Nylon 6 is made from caprolactam, while Nylon 6/6 is produced from hexamethylene and diamine/adipic acid. Some other nylon types, though, like Nylon 11, which we offer via selective laser sintering, can be made from renewable sources like castor bean plants by polymerizing undecanoic acid.

 

The numbering scheme for nylon can help with understanding the amount of carbon atoms in each reactant. For example, Nylon 6/6 indicates that there are six carbon atoms in the diamine and six carbon atoms in the diacid, while Nylon 6 is only made up of a single polymer that has six carbon atoms. For more information on this topic, feel free to check out our guide on the properties of nylon. Nylon is one of the strongest engineering plastics in the world. In addition to its high lubricity, it has great tensile strength and impact strength. Depending on the grade, nylon can have a tensile strength of between 40 MPa and 90 MPa. Often used in injection molding, Nylon 6/6 has a tensile strength of 85 MPa. Higher tensile strength variants are possible using filler materials, such as with our glass-filled nylon option, which reinforces the material and improves strength.

 

Nylon is used pretty much everywhere, from gears and ropes to textiles and parachutes, thanks to its wear resistance, tensile strength, chemical resistance, and great strength-to-weight ratio. Some Xometry users report opting for nylon as a lightweight alternative to metal.

 

5.Differences Between Polyamides and Nylons

Simply put, nylons are a type of polyamide. Although they don't make up an entire class of polymer, they are lower in cost, easier to process, and have a better balance of properties compared to aromatic and semi-aromatic polyamides. Unlike aromatic polyamides, or aramids for short, which have higher thermal resistance and tensile strength, nylon is the most common polyamide and is widely used across several sectors.

 

6.About Us

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