Unit 2 - Lecture 7 Topic 1

Question 1

Flax:

Answer 1

Likely the first plant fibre to be used in textiles, as it has been found in ancient ruins in Egypt and prehistoric lake dwellings of Switzerland. Linen is the fabric made from flax. Flax is a bast fibre, which comes from the stem of the plant. The fibres are held together by woody matter and cellular tissue. Retting is required to free fibres from the stem.

Question 2

What is the physical structure of flax like?

Answer 2

It is typically yellowish-white. It has a staple length ranging from 10-100 cm long - much longer than cotton fibres. The long fibres are known as line. Flax diameter ranges from 40-80 micrometers, which is 2-4x the diameter of cotton.

Question 3

Line:

Answer 3

A higher quality long fibre, used for spinning into yarns to make fabrics, ie. flax.

Question 4

Tow:

Answer 4

Short, coarse fibres removed during processing. Can be spun into yarn for heavier, coarser fabrics, or as stuffing in upholstery.

Question 5

What is the cellular structure of flax?

Answer 5

Flax is composed of cellulose - OH groups are very important in its structure. It has a higher DP than cotton (~18 000), which gives it more strength. Flax is highly crystalline (more than cotton), and more oriented.

Question 6

What is the submicroscopic structure of flax like?

Answer 6

Flax fibres are made up of multiple cells; each cell has crystalline fibrils of cellulose spiralling very slightly. With flax, bundles of crystalline fibrils are held together by an amorphous absorbent, cellulose-like, complex matrix. The cell wall is thicker in flax than in cotton. Also, flax has lumen (a central canal), cross markings, and irregular width along the fibre length with longitudinal lines.

Question 7

Nodes:

Answer 7

Cross markings on each fibre where cells overlap. Nodes are seen on fibres like flax.