What is the Difference Between Nylon 6 and Nylon 66?

Nylon 6 and Nylon 66 are both types of nylon, a thermoplastic linear polyamide, widely used in various engineering applications. The main difference between the two lies in their chemical structure and properties:

1. Chemical Structure: Nylon 6 is made from one monomer with 6 carbon atoms, while Nylon 66 is made from two monomers, each with 6 carbon atoms.
2. Mold Shrinkage: Nylon 6 has lower mold shrinkage, which means better dimensions and reliability in final part dimensions. Nylon 66 exhibits greater mold shrinkage.
3. Water Absorption: Nylon 6 absorbs more water than Nylon 66, which affects its properties, such as strength and weight.
4. Heat Deflection Temperature (HDT): Nylon 66 has a higher HDT, making it more suitable for applications that require higher temperature resistance.
5. Impact Strength: Under moist conditions, Nylon 6 has better impact strength and flex fatigue life than Nylon 66.
6. Crystallinity and Rigidity: Nylon 66 is slightly more rigid, allowing for better stretch recovery and higher abrasion resistance.
7. Chemical Resistance: Nylon 66 is reported to have better resistance to chemicals, such as saturated calcium chloride, compared to Nylon 6.
8. Melting Point and Heat Deflection Temperature: Nylon 6 has a lower melting point (215-220°C) and a lower heat deflection temperature (130-140°C) compared to Nylon 66, which has a higher melting point (250-265°C) and a higher heat deflection temperature.
9. Processing Temperature: Nylon 6 can be processed at lower temperatures compared to Nylon 66.

When selecting between Nylon 6 and Nylon 66 for a specific application, it is essential to consider these differences and the desired properties of the final product. It is often advised to seek expert advice to make an informed decision.

Comparative Table: Nylon 6 vs Nylon 66

Nylon 6 and Nylon 66 are both synthetic polymers known as polyamides, but they have some differences in their characteristics and applications. Here is a table comparing the two:

Nylon 6 is created from a single monomer, caprolactam, while Nylon 66 is produced from two different monomers, adipic acid and hexamethylene diamine. Nylon 6 has a lower melting point and is less crystalline than Nylon 66. Nylon 6 is also more flexible and has a higher water absorption rate and lower heat age strength than Nylon 66. Nylon 66, on the other hand, has a higher melting point, greater crystallinity, and higher heat age strength, making it more resistant to heat and suitable for industrial applications.