Fibre Properties: 

Textile production starts long before fabrics are woven or garments are sewn. It begins at the level of the fibre. The world around us gives us a huge range of natural and man‑made fibres but not all fibres have the properties necessary to become textile fibres. A fibre must have certain essential characteristics so that it can be spun into yarn and then converted into fabrics. These characteristics, referred to as fibre properties, influence not only the behavior of the fibre during processing, but also the appearance, handle and performance of the final fabric.

Fibre properties are generally classified into two major groups:

Primary (Essential) Properties

Secondary (Desirable) Properties

Let’s explore each group in detail.

Primary Properties of Textile Fibres

Primary properties are those essential properties a fibre must have to be suitable for textile use. Fibres lacking these properties cannot be efficiently spun, woven or knitted. They directly affect the spinning performance, yarn formation and fabric durability.

Fibre Length-to-Width Ratio

Also known as the aspect ratio, this is the relationship between the fibre’s length and its diameter.

• A fibre must be long enough to be twisted into a yarn.
• Ideally, the diameter should be 1/100 of its length.
• Longer, finer fibres allow better twisting and produce smoother, stronger yarns.
• In Lesson‑5, you will learn how this property affects the spinning process.

Tenacity (Strength)

Tenacity refers to the strength of the fibre, measured as the force required to break it.

• Higher tenacity fibres can withstand mechanical processing.
• Stronger fibres result in durable and long‑lasting fabrics.
• For example, nylon has high tenacity, whereas wool has moderate strength.

Flexibility (Pliability)

Flexibility is the fibre’s ability to bend or move without breaking.

• A fibre that can flex easily will not snap during carding, drawing, roving and spinning.
• Flexible fibres also produce softer and more drapeable fabrics.

Fibre Uniformity

Uniformity refers to the consistency of fibre diameter and length.

• Natural fibres are often irregular, so they require sorting and grading.
• Poor uniformity leads to weak, uneven yarns and rough fabrics.
• Uniform fibres improve yarn smoothness and strength.

Cohesiveness (Spinning Quality)

 means the tendency of the fibre to hold together during spinning.

• Influenced by fibre surface texture and cross‑section shape.
• Wool fibres, with their scaly surfaces, have excellent cohesiveness.
• Smooth fibres like polyester may need higher twist for yarn formation.

 Secondary Properties of Textile Fibres

Primary properties are those that determine the usability of a fibre in textile industry. Secondary properties influence the performance of a fibre in a fabric. These include physical, chemical and biological properties which influence appearance, comfort, durability and care requirements.

Physical Properties

Morphology

Fibre morphology includes the structure, shape and internal arrangement of the fibre.

• Most fibres require microscopic study due to their fineness.
• Features like scales, convolutions or smoothness affect performance.

Longitudinal View

This is the lengthwise appearance of the fibre when viewed under a microscope.

Cross‑Sectional View

This is the appearance of the fibre when cut horizontally, like slicing a cucumber.

• Cross‑sections may be round, triangular, kidney‑shaped or multilobed.
• Cross‑section influences lustre, bulk, moisture behaviour and feel.

 Lustre

Lustre refers to the shine or gloss of a fibre. It is the result of how light reflects off its surface.

• Filament fibres (e.g., silk, polyester) are more lustrous.
• Staple fibres (e.g., cotton) have a duller appearance unless treated.

Colour

Natural fibres have inherent colours determined by climate, soil and environmental conditions.

• Cotton often appears off‑white or creamy.
• Wool can be white, brown or grey.
• Fabrics are usually bleached before dyeing to achieve richer colours.

Elongation and Elastic Recovery

• Elongation is how much a fibre can stretch before breaking.
• Elastic recovery is the ability to go back to original length.
• High elasticity prevents sagging and improves comfort.

Moisture Absorption

Also called hygroscopicity, this is the fibre’s ability to absorb water.

• Highly absorbent fibres (cotton, wool) are more comfortable in hot climates.
• Low absorbency fibres generate more static electricity.

Resiliency

Resiliency is the ability to spring back after being folded, crushed or wrinkled.

• Wool has high resiliency (wrinkle‑resistant).
• Cotton has low resiliency (wrinkles easily).

Dimensional Stability

The ability of a fibre to retain its shape and size despite moisture, heat or mechanical stress.

• Poor dimensional stability causes shrinkage or stretching.

Abrasion Resistance

Resistance to rubbing or surface wear.

• Important for fabrics used in uniforms, upholstery and sportswear.

 Thermal Properties

How a fibre reacts to heat and flame:

• Thermoplastic fibres melt (e.g., polyester).
• Natural fibres ignite but do not melt.

 Static Electricity

Fibres with low moisture content (e.g., nylon, acrylic) generate more static charges due to friction.

Chemical Properties

 Effect of Acids

• Strong mineral acids like sulphuric acid damage cellulose fibres (cotton, linen) and wool.
• Mild organic acids may not harm fibres significantly.

Effect of Alkalis

• Alkalis (like in detergents) do not harm cotton.
• Alkalis weaken or dissolve protein fibres like wool and silk.

 Effect of Sunlight

Prolonged exposure to sunlight can cause:

• Yellowing of fabrics
• Fibre degradation
• Strength loss
  Some fibres, such as nylon, are particularly sensitive.

Biological Properties

This includes fibre resistance to fungi, bacteria, insects and pests.

• Wool and silk are prone to moth and beetle attacks.
• Cellulosic fibres may develop mildew when stored in damp conditions.

Proper storage conditions—dry, cool and well‑ventilated—are essential to prevent biological damage.