NYLON-6与NYLON-66的差异性

Nylon 6 results from open ring polymerization of only one monomer caprolactam. It is called Nylon 6 because of containg 6 carbon atioms in it.

Nylon 66 is a polymer formed from condensation polymerization of Hexa methylene di-ammine and adipic acid. It contains 12 carbon atoms that comes from its two monomers. As each of them has 6 carbon atoms in their structure.

The numbers of repeat units along the polymer chains of nylon 6.6 and nylon 6 are about 65 and 130, respectively. Both types of nylon contain weakly basic amino and weakly acidic carboxylic acid end groups.

Nylon 6 and nylon 6.6 are strong fibers with moderate elasticity, even after drawing. Nylon 6 has a somewhat lower elastic modulus and better elastic recovery than nylon 6.6 and therefore gives more flexible fabrics of softer handle.

Both nylons are available in high tenacity variations for industrial uses. In fact, the mechanical properties can be varied considerably by changes in the polymerization and drawing conditions.

Heat setting of nylon materials may be carried out under dry conditions in hot air at 190 °C for nylon 6, or 205 °C for nylon 6.6. Alternatively, setting is achieved in steam at 120 or 135 °C, respectively.

At higher temperature like 180°C, Nylon 66 shows better heat age strength of 11.5 kg whereas Nylon 6 breaks down at 2.5 kg. The fibers of Nylon 66 are 33% more resistant to abrasion than Nylon 6. They can withstand 60,000 cycles while Nylon 6 can withstand 40,000 cycles at the same conditions. 

Low creep, more crystalinity makes it slightly stiffer and better equipped, again its good stretch recovery, and higher abrasion resistance makes Nylon 66 more suitable for industrial use.