Types of Fibres

Question 1

What is Synthetic Fibres

Answer 1

man made fibres spun from synthesized fibre forming polymers.

Question 2

Regenated fibres are

Answer 2

man made fibres that have been produced from naturally occuring polymers by a technique that includes the regeneration of polymer structure.

Question 3

Subdivisons of Natural Fibres

Answer 3

Animal (protein)
Vegetable (cellulose)
Mineral (asbestos)

Question 4

Characteristics of Fibre Polymers

Answer 4

1. Linear molecular chains which possess some degree of extension to the fibre axis.
2. Streamlined molecular chains.
3. The molecular chains should be flexible and hence impart extensibility to the fibres.
4. Have a high molecular weight

Question 5

What is dry spinning?

Answer 5

Involves dissolving the polymer into a solution that can be evaporated.

Question 6

What is wet spinning?

Answer 6

Involves dissolving polymer into a solvent which and the polymer solution is extruded through spinneret into a solvent-non solvent mixture

Question 7

What is melt spinning?

Answer 7

Involves melting the polymer then extruding it through a spinneret where it is then drawn out to create spools.

Question 8

Source of Vegetable/ Cellulose Based Fibre?

Answer 8

1. Seed
2. Stem/Bast
3. Leaves

Question 9

What are examples of seed fibres?

Answer 9

Cotton, Kapok and Brazil Nut

Question 10

What are examples of stem fibres?

Answer 10

Flax and Hemp

Question 11

What are examples of leaf fibres?

Answer 11

New Zealand Hemp, Sisal and Aboca

Question 12

Sources of Animal/Protein Based Fibre?

Answer 12

Goat, Camel, Rabbit, Sheep and Silkworms

Question 13

What is goat hair most famously used for?

Answer 13

Goat Hair is used to create cashmere.

Question 14

What fibres are rabbit fur mainly mixed with?

Answer 14

Nylon and Wool

Question 15

What is responsible for the higher specificity gravity of Nomex over nylon?

Answer 15

Nomex is made of aromatic polyamides called aramids. Aramids have an almost perfect polymer chain caused by its molecular linearity and hydrogen bonding. These chains is the reason for it’s higher specificity of gravity.

Question 16

Between Nomex and Nylon which of the two fibres would be more useful for application in a floatation device?

Answer 16

Nylon would be the more useful because of its low moisture regain as a result of it’s crystalline structure.

Question 17

Why do fibre wrinkle?

Answer 17

Fibre wrinkle through the process of wetting then drying. When a fibre is wet the weaker chains within the fibre will break and upon drying will reconnect in a different area of the fibre.

Question 18

Why are some aramids suitable for high performance products?

Answer 18

Aramids are extremely strong, resistance to breaking, stretching, heat and some chemicals.

Question 19

Compare the properties of nylon and polyester. Say why nylon is more suitable for making stockings than polyester. Why do we see more nylon than silk stockings?

Answer 19

Polyester and Nylon have many things in common like they are both strong, resistance to abrasion, thermally stable and able to hold a good setting treatment. However, nylon has a better elasticity recovery than that of polyester which would make it more suitable for stockings. Polyester would require twice as much force to stretch.

Question 20

What is responsible for the higher modules of polyester over nylon?

Answer 20

Polyester has para substituted benzene ring that makes it crystalline and stiff.

Question 21

What properties of silk causes it to dissolve in cuprammonium hydroxide unlike other animal fibres?

Answer 21

Silk is cellulose based fibre unlike its other animal based fibres as a result it readily dissolves in cuprammonium hydroxide.

Question 22

What are the benefits of garments made of alpaca have over the garments made of wool?

Answer 22

Garments made of alpaca are known to be hypoallergenic unlike garments made of wool. This means many people may have a hypersensitive reaction to wool versus alpaca fibre.

Question 23

Why is it that white cotton fibre are of little evidential value?

Answer 23

White fibre is manufactured in bulks on a daily basis and is one of the mot commonly used fibres out there as a result it is difficult for examiners to differentiate where this evidence might have originated from.

Question 24

What are the benefits of spinning in the manufacturing of synethic and regenerated fibres?

Answer 24

Spinning is a good way of making strong fibres because it allows inter polymer forces of attraction between polymers to maximise.

Question 25

How is nylon 6.6 structcally different from nylon 6?

Answer 25

Nylon 6 has one monomer of carbon with 6 carbon atoms whereas nylon 6.6 has two monomer of carbon with 6 carbon atoms each.

Question 26

Why are polyolefins suitable for use in active wear?

Answer 26

Polyolefins have a low moisture regain which are a result of its crystalline and hydrophobic nature.

Question 27

What is difference between raw and degummed silk?

Answer 27

Raw silk is coarse and lack luster whereas degummed silk is soft and has shine to it.

Question 28

What are the steps in the silk production?

Answer 28

Sericulture and Silk Reeling

Question 29

What is sericulture?

Answer 29

Sericulture is the process of producing cocoons from the eggs of the silkworm.

Question 30

What is Silk Reeling?

Answer 30

Silk Reeling is the process of turning the cocoons into thread.

Question 31

Why is it so difficult to analyse wool evidence?

Answer 31

When shearing a sheep is done there are multiple sections a shearer might remove the hair from as a result it is difficult for examiners to pin point the specific region because the hairs may differ significantly.