Nylon 66 Polymer – Step Reaction Polymerization


Nylon-66 is a polyamide fibre which is manufactured by a process that involves step growth polymerization and condensation polymerization. The generic term used to define long chain synthetic polyamides is Nylon. One of the key members from the group of poly-condensation products of acids and diamines, Nylon-66 has great abrasion resistance, strength andresistance towards heat, water and chemicals.

When compared with Nylon 6, Nylon-66 is a superior version due to its higher melting point, greater dimensional stability and a more compact molecular structure. With a guarantee of excellent performance in high speed spinning processes, it also has good UV light-fastness and dye wash fastness.

There are different ways of referring to Nylon-66 as Nylon 6-6, Nylon 6,6 etc. The Nylon 66 polymer is made of hexamethylenediamine and adipic acid which provides Nylon 66, a total of 12 carbon atoms in each repeating unit.

Availability of Nylon 66

Easily available in both sheet and rod form, Nylon 66 has a wide range of applications. Generally the rods are available from 4mm-200mm diameter and the sheets are from 5mm thick to 100 mm thick.

Manufacturing Process

The ingredients i.e. Hexamethylenediamine and adipic acid are combined with water in a reactor. The outcome of this process is the nylon salt which is sent for evaporation which removes any excess water. The nylon salt is then passed through a reaction vessel where a continuous polymerization process makes molten Nylon 6,6. The molten nylon is then passed through a spinning process, with Nylon-66 extruded and sent via spinneret. Once the nylon is air cooled to form filaments.

Favourable Temperatures

Nylon-66 can operate at temperatures exceeding 100 °C, where the maximum limit is 160 °C and generally allowed only for short term applications.

Various Applications

Probably, one of the most important and popular engineering plastic, it can be utilized for a wide range of applications like bearings, gears, pulleys, screws, bushes etc.

Around 55 years back, Remington Nylon 66 took polymers to a new level with the introduction of world’s first mass produced rifle made from something other than wood.


The long molecular chains of Nylon 66 results in higher number of hydrogen bonds which also makes it extremely resilient. Being an amorphous solid, it is slightly soluble in boiling water and has large elastic properties. It offers immaculate dimensional stability, high melting point and excellent abrasion resistance. With the use of reinforcements, the physical strength of Nylon-66 can be improved multiple times. Few popular applications of Nylon includes carpet fibres, swimwear, parachutes, tyres, ropes and air bags etc.