Created in 1930 by Wallace Hume Caruthers, Nylon is used for a variety of products because of its heat resistance and toughness at both high and low temperatures. However, both Nylon 6 and Nylon 6,6 (also called Nylon 6-6) differ in their uses and chemical properties, making each Nylon suitable for certain industries and products.
Both Nylon 6 and Nylon 6,6's polyamide chains are held together using hydrogen bonds, adding to the strength and dexterity of the fibers. Nylon 6's crystal structure contains parallel chains with hydrogen bonds between each chain, forming a more open structure with less internal hydrogen bonding. Compared to Nylon 6's crystal structure, Nylon 6,6 is tighter with less openings, making it the stronger and more resistant to heat of the two Nylons. Since Nylon 6,6's structure contains no set direction it makes the surface 12 percent harder and 20 percent more resilient than Nylon 6.
Differences in Properties
Both Nylon 6,6 and Nylon 6 are 100 percent elastic while under an 8 percent extension. However, both differ in their melting points, with Nylon 6 melting at 216 degrees Celsius and Nylon 6,6 having a melting point of 263 degrees Celsius. This makes Nylon 6,6 the preferred Nylon for temperature performance products. Both Nylon 6 and 6,6 allow easy dyeing and washing and both provide a chemically stable product.
Each Nylon is preferred over the other in certain cases due to physical properties. For example, Nylon 6,6 is preferred over 6 for making carpets because of its higher strength and toughness. Nylon 6 is primarily used in the textile industry for making clothing, ropes, threads, nets and garments while Nylon 6,6 is used for tire ropes, gear wheels, friction bearings and plug parts.