20 Differences between Nylon 6 and Nylon 66

Nylon is an important synthetic material for industrial purposes. It has many variants like Nylon 66, Nylon 6, Nylon 5,10, Nylon 6,12, Nylon 11 etc. What to choose, a little bit confusing, right? Find out the differences between Nylon 6 and Nylon 66 right below!! You will get to know about nylon 6, nylon 6,6, along with their application area in brief in this article.

For High mechanical damping ability, good sliding properties, excellent wear resistance, good electrical insulating properties, and good resistance to high energy radiation, Nylon becomes incredibly popular for different industrial purposes. 

A quick glance at the difference between Nylon 6 and Nylon 66

Basically, the main difference between Nylon 6 and Nylon 66 is in their chemical structure. Both of them are popular for their durability and lightweight properties. Nylon 6 is formed from Caprolactam by open-ring polymerization, having a lower melting point. 

Whereas Nylon 66 is formed from hexamethylene diamine and Adipic acid through a condensation polymerization reaction, it has a higher melting point. The latter property makes it suitable for high-performance industrial use.

It provides good insulation and damping properties. Toughness, stiffness, and hardness are the characteristics of nylon 6. It has a lustrous finish, along it exhibits good dye affinity.

Uses of Nylon 6

• Hosiery
• Industrial yarn
• Upholstery
• Heavy duty fabric
• Toothbrush fiber

Uses of Nylon 66

Its micro denier form is mostly used in apparel such as industrial workwear. Heavy denier is used in-

• Tire cord
• Automotive airbags
• Parachutes
• Carpets

As Nylon 6 is a bit lustrous than Nylon 66, it is suitable for radiator grilles, stadium seats or firearm components where we need an attractive lustrous finish.

Differences between Nylon 6 and Nylon 66 in detail!!

Topics	Nylon 6	Nylon 66
No. of carbon atoms in structure	No of carbon atoms are 6. It represents that it has 6 carbon atoms in the backbone of its chain	Nylon 66 has two 6 numbers. It indicates the number of carbons in the acid and ammine residues. So it has 12 carbon atoms.
Requirement of monomer	Only one monomer is required	Two monomers are required
Monomer used	Caprolactam	Hexa-mythelene di-amine and Adipic acid
Polymerization technique	It is known as poly-caprolactam which is formed by open ring polymerization	This polyamide is formed by condensation polymerization
Melting point	Lower (215-220°C)	Higher (250-265°C)
Crystallinity	Less	More
Water absorption rate	High	Low
Chemical resistance to acid	Poor	Good
Heat deflection temperature	Low	High
Moisture regain	4-4.5%	4-4.5%
Chemical name	Poly (6-aminocaproic acid)	Poly [Immino (1,6-dioxohexamythelene)immio hexamythelene]
Density	1.15 g/ml	1.2 g/ml
Degree of polymerization	200	60-80
Recyclability	More recyclable than nylon 66	Less recyclable than nylon 6
Tensile strength	6.2 × 104 kPa	8.3 × 104 kPa
Glass transition temperature (Tg)	Dry – 60Tg reduces with the increase in moisture content	Dry – 70
Molecular mobility	High	Low
Color fastness	Less than nylon 66	Better
Dye affinity	Great dye affinity	Shows less dye affinity than nylon 6
Temperature resistance	Less than nylon 66	Better
Stain clean-ability	Low	High
Resilience	Low	high
Mold shrinkage	Low	More
Heat setting at hot air	190°C	205°C
Internal structure	Less compact	More compact
Heat setting at steam	120°C	135°C
Application	Radiator grilles, stadium seats or firearm components	Friction bearings, battery modules, luggage and conveyor belts
Elastic modulus	Lower	Higher
Elastic recovery	Better	Lower than nylon 6
Luster	More lustrous surface	Less lustrous surface

To Sum Up!!

So, what should you choose for your specific purpose? You will clearly get your answer if you understand the differences between nylon 6 and nylon 66.

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