Nylon-6,6 (PA66) is semi-crystalline poly amide commonly used in fiber applications such as carpeting, clothing, and tire cord. It is also used as an engineering material in bearings and gears due to its good abrasion resistance and self-lubricating properties.
Properties of Nylon 6,6
Nylon 6,6 is made by the linear condensation polymerization of hexamethylene diamine and adipic acid. A polymer with high molecular weight is obtained when the two reactants are present in ratio 1:1. The mixture of hexamethylene diamine and adipic acid after carbon treatment are passed into suitable mixing tank. Heating the salt of adipic acid and hexamethylene diamine concentrated aqueus solution in the presence of a little acetic acid gives polyhexamethylene adipamide.
The molten mixture is heated to 280oC under nitrogen to avoid oxidation. The molten liquid polymer is extruded a thick ribon, cooled to solidify and cut it into chips. Then they are passed through a high temperature reactor with a temperature of 235oC for pre-polymer. Pressure is released at a temperature of 260oC-290oC. Then the polymer is pumped to a finisher, a thin-film evaporator and maintained temperature 260oC-290oC in a finisher and is discharged from this unit reached for spinning into fibers.
Diagram of manufacturing process of Nylon-6, 6
Properties of Nylon 6,6
- Glass transition temperature: 50oC.
- Melting temperature: 255oC.
- Amorphous density at 25oC: 1.07 g/cm3.
- Crystalline density at 25oC: 1.24 g/cm3.
- Molecular weight of repeat unit: 226.32 g/mol.
Nylon 6,6 is made by the linear condensation polymerization of hexamethylene diamine and adipic acid. A polymer with high molecular weight is obtained when the two reactants are present in ratio 1:1. The mixture of hexamethylene diamine and adipic acid after carbon treatment are passed into suitable mixing tank. Heating the salt of adipic acid and hexamethylene diamine concentrated aqueus solution in the presence of a little acetic acid gives polyhexamethylene adipamide.
The molten mixture is heated to 280oC under nitrogen to avoid oxidation. The molten liquid polymer is extruded a thick ribon, cooled to solidify and cut it into chips. Then they are passed through a high temperature reactor with a temperature of 235oC for pre-polymer. Pressure is released at a temperature of 260oC-290oC. Then the polymer is pumped to a finisher, a thin-film evaporator and maintained temperature 260oC-290oC in a finisher and is discharged from this unit reached for spinning into fibers.
Diagram of manufacturing process of Nylon-6, 6
Fig: Diagram of manufacturing process of Nylon-6, 6
The reaction of nylon 6, 6
The two monomers of adipic acid and hexamethylene diamine are made nylon6, 6 polymers.
The two monomers of adipic acid and hexamethylene diamine are made nylon6, 6 polymers.
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