Fibres and Yarns: Types, Properties and Identification
Fibres and Yarns: Types, Properties and Identification
The exam tests classification first, then the link between a fibre's property and its end use, and finally simple identification tests that a weaver can actually perform.
Classification and properties
- Natural cellulosic: cotton (absorbent, good wet strength, dyes easily, creases), jute (strong, coarse, cheap, rots when damp), linen and ramie (strong, lustrous, stiff).
- Natural protein: silk (filament, high lustre, elastic, weaker when wet) and wool (crimped, insulating, felts, weak when wet).
- Regenerated: viscose and modal (soft, absorbent, low wet strength). Synthetic: polyester, nylon, acrylic (strong, quick-drying, thermoplastic, low absorbency).
Yarn types and counts
Spun yarn is made from staple fibres twisted together; filament yarn comes from continuous filaments; ply yarn is two or more single yarns twisted together (2/60s = two plies of 60s cotton). Cotton is numbered in Ne, silk in denier, jute in lbs per spindle.
Worked example
A sample burns quickly with a yellow flame, smells of burning paper and leaves soft grey ash. Reasoning: burnt-paper odour plus feathery ash means a cellulose fibre, so cotton, linen or viscose. It is confirmed as cotton because the fibres show convolutions under the microscope and the yarn is a low-twist spun yarn; viscose would feel smoother, and silk would not smell of paper.
Marks-losing traps
- 'Silk cotton' (kapok) is a vegetable fibre, not silk.
- Mercerised cotton is still cotton; eri and muga are non-mulberry silks, not mulberry pat.
- Classifying viscose as synthetic - it is regenerated cellulosic.
- Judging a fibre only by feel; the burning test needs both odour and residue.