Nylon 6,6
A polyamide used in locking cable ties and drawn cleaning-brush filaments.
- Also known as
- nylon, nylon 66, nylon 6,6, PA66, polyamide 66
In everyday products
- Cable tie — Strap and locking head
- Nylon 6,6 cleaning brush — PA66 brush filaments
Structure and behaviour
[–NH–(CH₂)₆–NH–C(=O)–(CH₂)₄–C(=O)–]ₙ
Amide links join the six-carbon diamine and six-carbon diacid residues; the diacid count includes its carbonyl carbons. N–H groups and carbonyl oxygen atoms allow hydrogen bonding between adjacent chains.
- Interchain hydrogen bonding helps give strength to thin mouldings and drawn filaments.
- A cable tie combines a flexible strap with a relatively rigid ratchet head; section shape and moulded detail create those different jobs.
- Drawing filaments orients chains for bristles, whereas injection moulding is used for a locking tie.
- Absorbed water changes the balance between stiffness and toughness. Dry and humidity-conditioned test results are not directly interchangeable.
- Both nylon 6 and nylon 6,6 are polyamides, but their repeat-unit sequence and monomer routes differ.
Preparation routes
Adipic acid and diamine route
Nylon salt formation, then polycondensation. The acid and diamine form a balanced salt. Heating allows amide links to form, releasing water as the nylon 6,6 chains grow. The balanced pair supplies alternating acid-derived and amine-derived sections. The two carbonyl carbons count among the six carbons of the acid segment.
Heat and water removal support chain growth. Both the acid and the diamine are required. The acid route releases water; a laboratory acid-chloride demonstration has different reagents and by-products.
- PA 6 and PA 66 intermediatesBASF
- Reference document on best available techniques in the production of polymersEuropean Commission, Joint Research Centre · 2007
Material limits
PA66 moisture content affects dimensions and mechanics; bristle stiffness also depends on length and diameter. Separate components for recycling.
Sources
- Reference document on best available techniques in the production of polymersEuropean Commission, Joint Research Centre · 2007
- T50I cable tie: PA66 material and product specificationHellermannTyton
- Ultramid polyamides: processing, moisture and conditioningBASF
- Nylon filaments for household cleaning brushesTai Hing
- Sustainable plastics: the role of chemistryRoyal Society of Chemistry