Nylon 6 and Nylon 66: Similarities and Differences Analyzed

Many thermoplastic polymers have become an integral part of our lives and nylon is one of them. These thermoplastics belong to the family of polyamides, and are widely used for making different commercial and industrial applications. Nylon 6 and nylon 6/6 are two popular commercial nylon grades that have gained immense popularity in recent years. Here the numbers 6 and 6/6 describe the numbers of polymer chains present in their structure. These nylon grades have good durability and strength, and they share several common characteristics and differences. This post guides you through these similarities and dissimilarities and help you make the right selection.

Nylon 6 and Nylon 66 – Chemical Structures Compared

Nylon 6 and 66 have slightly different chemical structures. The following pointers will help you understand it better.

  • Nylon 6 is made of a single monomer, which is caprolactam. This monomer has a formula (CH2)5C (O) NH and it has 6 carbon atoms. The demand for caprolactam has increased in recent years, so has the demand for nylon 6.
  • Nylon 66 comprises two monomers, which are hexamethylene diamine and adipoyl chloride, with 12 carbon atoms in total. These monomers form a strong chemical bond, which lends a crystalline structure to the nylon. This crystalline structure also adds to the capabilities of nylon such as improved temperature sustainability and stiffness.
Nylon 6 and Nylon 66 – Similarities and Dissimilarities Analyzed

Before comparing nylon 6 and 66, let’s understand the common properties of nylon polymer.

  • Nylon assures good fatigue resistance, which makes it an ideal choice for industrial applications.
  • It possesses excellent stiffness, hardness, strength, and toughness.
  • The polymer also offers excellent mechanical dumping and sliding ability.
  • It can resist wear and tear, and harsh high-energy radiation such as x-ray and gamma rays.
  • The material also offers excellent machinability.

Nylon 6 and 66 also share these properties, which makes them similar in many ways. However, they largely differ due to their chemical structure. The following pointers will help you understand it better.

  • Nylon 6 is less crystalline compared to nylon 66.
  • Nylon 66 exhibits great mold shrinkage than nylon 6.
  • Nylon 66 has a higher melting point than nylon 6.
  • Nylon 6 has a low heat deflection temperature than nylon 66.
  • Of these two, Nylon 6 has a high water absorption rate and poor resistance to acids.
  • Nylon 6 can withstand high stress, high impact, and can sustain most hydrocarbons.
  • Nylon 6 stands out due to its brilliant lustrous finish and is easy to color, whereas nylon 66 is difficult to color.
A Few Pointers to Choose Between Nylon 6 and Nylon 66

Although knowing the similarities and dissimilarities of nylon 6 and nylon 66 may help, the following pointers will also help ease the selection:

  • Nylon 6 is suitable for applications that demand lightweight plastic with high impact strength.
  • It is also suited for applications that demand high aesthetic appeal. This type is easier to dye and has a lustrous finish.
  • Nylon 6 is not ideal for applications where it may be exposed to a water surface for a long time.
  • Nylon 66 is ideal for applications where they may be exposed to water.
If you are looking for either of these nylon grades for your industrial applications, it is important that you source them from trusted manufacturers or suppliers. Mid Continent Plastics buys and sells different types of nylon grades including nylon 6, nylon 66, nylon 4/6, nylon 6/10, nylon 11, nylon 6/12, and nylon 12. The company accepts and sells these polymers in regrind as well as virgin forms.

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