Unit 1 - Lecture 4 Topic 1

Question 1

What are physical properties of fibres?

Answer 1

Length, shape and contour, fibre diameter and fineness, density and specific gravity, fibre crimp, and colour.

Question 2

Staple Fibres:

Answer 2

Short, measured in centimetres or inches, which includes all natural fibres (except silk). They appear soft, matte, and fuzzy with visible fibre ends. They are prone to abrasion, and provide warmth by trapping air.

Question 3

Filament Fibres:

Answer 3

Long fibres measured in miles or kilometres that are either made of monofilaments or multifilaments. They can be smooth and flat or bulk and textured and can be cut into staple lengths.

Question 4

Bulked Filament:

Answer 4

Soft and matte fibres with invisible fibre ends. They provide warmth as the crimped structure traps air and feels soft.

Question 5

Smooth Filament:

Answer 5

Shiny, lustrous and smooth fibres that are often prone to snagging. They are cool to the touch and feel silky.

Question 6

Shape and Contour:

Answer 6

Cross-sectional shape of the fibre e.g. circular, oval, triangular, tri-lobal and contoured outer surface of the fibre e.g. smooth, rough, serrated. Shape and contour influences the amount of light reflected (lustre). Natural fibres (with the exception of silk) tend to be duller than manufactured fibres.

Question 7

How do natural fibres derive their shape?

Answer 7

1. The way the cellulose is built during plant growth (ie. cotton)
2. The shape of the hair follicle and the formation of protein substances in animal (ie. wool)
3. The shape of the orifice through which the insect extrudes the fibre (ie. silk).

Question 8

How do manufactured fibres get their shape and contour?

Answer 8

Shape is controlled by the shape of the spinneret. This mechanism can also modify size, luster and length.

Question 9

What does shape and contour influence?

Answer 9

Comfort (how it feels, warmth) and appearance (lustre, cover/opacity).

Question 10

Fibre diameter/fineness:

Answer 10

Measured in micrometers (microns) and expressed as a fibre fineness. Natural fibres are usually irregular and not uniform, so average measurements are taken. This is typically unnecessary with manufactured fibres. Fineness is described as denier or tex (linear density). Diameter is usually more consistent.

Question 11

Density and Specific Gravity:

Answer 11

Terms used in relation to the weight of the fibre measured by mass per unit of volume (g/cm^3). The ratio of fibre mass to
equal volume of water at 4°C is the base measurement.

Question 12

What does fibre diameter, fineness, and density influence?

Answer 12

Comfort (material weight, fabric sensory) and appearance (resistance to crushing and wrinkling and drapery).

Question 13

Fibre Crimp:

Answer 13

Waves, bends, or twists along the length of a fibre. This can be 3D (eg, many animal hairs) or 2D (added to synthetic fibres) and can be elongated more than straight fibres (think spring/coil vs. rope)

Question 14

What does fibre crim influence?

Answer 14

Compression resiliency, warmth and fabric hang, and appearance (cover.opacity, wrinkle resistsance/revovery.

Question 15

Fibre colour:

Answer 15

Colour in fibres can vary naturally (eg, off-white, tan, brown, black). Manufactured fibres usually are white or off-white but colour can be added later to fibres (eg, dyeing). Colour influences appearance.