2A Aramids

Question 1

What are aramid fibres?

Answer 1

A generic name for a family of synthetic polymer fibres made from petrochemicals, which are expensive high-tech fibres with a wide variety of end-uses

Question 2

Features of aramids

Answer 2

• 5x stronger than nylon
• can be engineered to exact specifications and to produce (non-)woven/knitted/cabled technical textiles to provide strength and heat resistance
• far exceeds steel and specialist metal alloys (e.g. Mg alloys for aerospace engineering)
• often used in combination with other materials to form composites
• low flammability and no melting point
• heat and cut resistance
• engineered yarns provide greater levels of cut/heat/durability protection

Question 3

Kevlar® properties

Answer 3

• 5x stronger than steel of an equivalent length
• flexible
• comfortable
• lightweight
• flame/chemical resistant
• very heat resistant: decomposes above 400ºC without melting

Question 4

Kevlar® uses

Answer 4

• protective wear (e.g. clothing/gloves/helmets) for bikers/extreme sports
• bullet-proof vests (soft armour)
• fire suits
• yacht sails
• skis
• tennis racquets

Question 5

Nomex® properties

Answer 5

• heat/flame resistant
• anti-static
• low shrinkage
• easy-care
• comfortable
• resistant to most industrial oils/chemicals/solvents
• durable
• can be dyed easily

Question 6

Nomex® uses

Answer 6

• protective clothing: armed forces/police
• firefighter suits
• high risk sports (e.g. motor racing): overalls/head cover/underwear that protects drivers/mechanics from flames and heat

Question 7

Nomex® and fire

Answer 7

Burns when you hold a flame up to it and stops burning as soon as the heat source is removed.

The thick woven structure of the synthetic fibres means that Nomex® is a very poor conductor of heat so it takes time for heat to travel through the fabric