WEEK 2
CLASSES AND PROPERTIES OF FIBRES
Fibres are classified into two main classes. Namely;
- The natural fibres; which are gotten from either plant e.g cotton and linen; or from animals e.g wool and silk.
- The man-made fibres; which are gotten from cellulose based fibres e.g viscose rayon and acetate or from non-cellulose based e.g nylon, polyester and acrylics.
PROPERTIES OF FIBRES
A. COTTON: Cotton is a vegetable fibre. It is made from cotton balls of the cotton plant. The cotton fibres surround the seeds of the cotton plant.
PROPERTIES OF COTTON
- It absorbs moisture quickly
- It is reasonably strong and durable
- It washes well
- It can be dyed easily
- It is cool and comfortable to wear.
B. LINEN: Is a vegetable fibre. It is gotten from the stem of flax plant. The flax plant grows in countries such as France, Russia, it is not produced in Nigeria.
PROPERTIES
- It is stronger than cotton
- It is absorbent and cool to wear
- It dries slowly
- It washes well
- It is a good conductor of heat.
C. WOOL; is an animal fibre. It is gotten from the hair of fleece f sheep. The hair of camel, Angora, rabbit or angora goat can also be used. It is commonly produced in Britain, Australia e.t.c.
PROPERTIES
- A wool fibre has a scaly appearance
- It is stronger when dry than when wet.
- It gives the smell of burning feather when burnt.
- It makes a very absorbent fabrics
- It is readily affected by bleach
D. SILK; is an animal fibre. It is produced by silk worm. Silk is produced chiefly in France, Italy, China and Japan.
PROPERTIES
- It is a very strong fibre
- It is smooth and fine
- It is warm to touch
- It absorbs moisture easily
- It is an expensive fibre
E. VISCOSE RAYON; is made by treating wood pulp or cotton linters with certain chemicals
PROPERTIES
- It is not very strong especially when wet
- 2. it has smooth surface
- 3. resemble sink in appearance only
F. ACETATE; it is made from wood pulp or cotton linters treated with acetic and acid acetic anhydride
PROPERTIES
- it dries quickly
- it looses strength when wet
G. NYLON; is the family name for all synthetic polyamides
PROPERTIES
1.It is very strong
2. It is light in weight
3. It requires no ironing
4. It is durable.
MANUFACTURING PROCESS OF FIBRES
A COTTON; are processed from bolls by the following steps;
- Ginning
- Baling
- Clearing
- Carding
- Combing
- Drawing
- Spinning
- Dyeing
- Weaving
B. LINEN; Is produced from the stem of flax plant by the following steps
- Retting
- Breaking and scotching
- Combing
- Spinning
C. WOOL; wool fibres are produced into two forms
- Worsted yarn; this is made from long fibres
- Woollen yarn; this is made from short fibres
The major steps for the manufacturing of both forms are;
- Clipping
- Sorting
- Scouring
- Carbonizing
- Carding
- Spinning
- Weaving
D. RAYON
- The cellulose (wood pulp or cotton linters) is first purified
- The cellulose is then treated with the right chemicals. It is then changed into a thin liquid.
- The liquid is then forced through a nozzle containing many fine holes called a spinneret. The rayon filaments or fibres are produced
- The filaments are spun into yarns. The yarns are woven into fabric
Assignment
Outline the manufacturing process of the following
- Silk
- Nylon
- Acetate.
EXPERIMENT AND TEST ON DIFFERENT FIBRES
FIBRES | APPEARANCE TEST | MICROSCOPIC TEST | BURNING TEST |
COTTON | It is cool to feel and fairly firm It has a dull appearance | Fibre is flat Has a twist characteristics Resembles a twisted ribbon | Burns in and out of flame Smells like burning paper Leaves very little grey or white powdery ash |
LINEN | It has a cool crisp handle Dull appearance | fibre is round and smooth with swellings or nodes at interval | Similar to cotton |
WOOL | Has a projecting fibre Rough and dull appearance Warm to handle | Wool fibre is covered with scales that overlap and point towards the top of the fibre | Does not burn but smoulders(i.e it burns slowly producing smoke but not flames Gives smell of burning hair or feathers |
SILK | Has a smooth and rich lustrous appearance Soft, smooth and resilient to harm | De-gummed fibre is very fine and has a smooth surface Raw silk fibres are seen as double filamentss | Similar to wool |
VISCOSE RAYON | has a smooth fairly soft handle A smooth lustrous appearance It may resemble silk | Fibre is rounded with groves running length-wise It looks like transparent rods streaked with wavy line | Similar to cotton |
ACETATE | Is silk-like and it drapes well Has smooth and soft handle Maybe dull or lustrous | Fibre is rounded with one or more surface ridges which look like thickened lines | Burns like cotton and gives a smell of acetic acid or vinegar Smell like boiling celery |
NYLON | Fabric is very smooth and slippery | Filament looks like a smooth glass rod | Shrinks like flame and melts into hard white or grey or bead. |