Study Unit 7: Manufactured non-cellulosic: polyamide NYLON Flashcards
History
The general public was first introduced to a truly synthetic fibre on 15 May 1940, when nylon stockings were launched after a successful mass advertising campaign. However, the history of nylon, started in 1927 when the DuPont Company decided to give a small group of scientists, under the leadership of Wallace Caruthers, unrestricted funds to do research into fibre development.
Fibre properties
Nylon has a protein-like molecule and is related chemically to the protein fibres wool and silk. It is a more expensive fibre than polyester and is used in applications where its specific properties are needed. Fabrics may be fine and soft or firm, according to fibre fineness, fabric construction and finishing. Fibres can be matte or lustrous depending on fibre cross-section and additives.
Physical structure
As with most other manufactured fibres, the length and diameter of nylon can be controlled. A wide range of cross-sections are produced, including, Y-shaped, trilobal, round, triangle, pentagonal and hollow. Filaments, textured filaments (about 80% of nylon filament production) and staple fibres are available.
Properties relating to durability
1. Abrasion resistance
Nylon has excellent abrasion resistance. Nylon carpet fibres can outwear all other fibres.
- Strength
Nylon is a very strong fibre. It can have a tenacity between 31–45 cN/tex. Tenacity drops when the fibre is wet by about 10–20%.
- Flexibility
Nylon has good flexibility.
- Elongation
Nylon has high elongation (16% at break).
Properties relating to comfort
1. Moisture absorption
Compared with natural fibres, nylon has rather low moisture absorption (moisture regain of about 3.5–5%). However, its regain is the highest for manufactured non-cellulosic fibres. Static can be a problem, particularly when the air is not humid.
- Heat conductivity
Nylon fibres are not good conductors of heat, but nylon fibres may or may not conduct heat well. Nylon can be made into very fine filaments which, if woven compactly, will result in a warm fabric. However, if extremely thin, lightweight, sheer fabrics are woven, they can be suitable for summer wear – though they are not as comfortable to wear as cotton and linen.
Properties relating to appearance retention
1. Resiliency
Nylon has excellent resiliency and therefore recovers well from creasing, wrinkling or crushing.
- Dimensional stability
Nylon is thermoplastic. It can be heat set so that it will retain its shape during use and washing. High temperatures are used for heat setting. Application of temperatures higher than those used for heat-setting may cause fibre deformation, shrinkage or even melting.
- Elasticity
Nylon is a highly elastic fibre (82–89% at 3% stretch). This property makes it suitable for end-uses where stretch and recovery are important.
Properties relating to care
1. Effect of alkalis
Alkalis have no effect on nylon.
- Effect of acids
Mineral acids will dissolve nylon or cause it to disintegrate. Nylon stockings have been known to disintegrate while being worn in industrial areas where acid fumes are present.
- Effect of sunlight
Sunlight causes gradual degradation of nylon. Therefore, it is not suitable for curtains.
- Biological properties
Mildew, bacteria or insects do not generally affect nylon.
Durability
Excellent
Abrasion resistance
Excellent
Tenacity
Excellent
Elongation
High
Comfort
Low
Absorbency
Low
Heat conductivity
Moderate
Appearance retention
High
Resiliency
High
Dimensional stability
High
Elastic recovery
Excellent
Care
Most items made from nylon can be machine washed
Warm water and a fabric softener to the final rinse cycle are recommended
Nylon tends to pick up colours from other items in the wash Wash white nylons separately to avoid a grey look
They can be hung out to dry (Nylon is quick drying) or tumble dried at low temperatures
Tumble drying can cause static build up
Remove articles from the dyer as soon as the cycle is completed
If ironing is required, use a warm iron. Safe ironing temperature 150 oC
Resistant to chlorine bleach
End Uses
It is used in‘Dri-mac’-type jackets and tracksuits, linings, lingerie, blouses, dresses and socks.
Its elastic recovery makes it suitable for hosiery (stockings), ski pants and swim suits.
It is also used in luggage and carpets.
It also has many industrial uses (eg belting, parachute fabric, cords, robes, netting, brush bristles, umbrellas and sporting goods).
Staple fibres are often used in blends with other fibres in these end uses.
