Textile Fibre properties

Textile Fiber Fiber is smallest part of fabric. An individual, fine, hair like substance. Fibers have comparatively high ratio of length to width thus

ensuring the flexibility required for manufacturing and end use.

Must possess certain physical, chemical and molecular properties. Readily available, economical and capable of being made into yarn, fabric or product.

Classification of Textile Fibres

Textile Fibres

Natural FibresRegenerated

FibresSynthetic Fibres

Sources of Man made fibres Made from chemical solutions that are forced through tiny

holes.

Device used to form the filaments called spinneret.

Different techniques are used to harden the liquid and produce filament fibers.

The technique used depends on chemical composition of solution.

Spinning Methods Dry Spinning method – fibre solution mixed with solvent is

forced through spinneret into warm air. The warm air helps evaporate. Eg. Acetate, modacrylic.

Wet Spinning method – solution is forced through spinneret and then into liquid solution in which fiber solution stream harden into continuous filaments.

eg. Acrylic, Viscose Rayon. Melt Spinning - solid material is melted to form liquid

solution that is forced through spinneret and into cool air where the liquid fiber streams harden into continuous filaments. Eg. Nylon, Polyester, Olefin etc.

Fibre Structure Fibre structure contributes to the performance characteristics

of a fabric and the products made from it. Physical attributes of the fiber: Fibre length Fibre Shape Fibre Surface Fibre Longitudinal configuration

Fibre length Fibres vary from < 1” to miles in length. Length measured in inches – staple fibres. Fibres of longer length – filament fibres. All man made fibres are produced originally as filament

fibres. They remain as such but often they are made into short length staple fibres.

Fibre Shape Under naked eye, all fibres look similar. Cross sectional shape of the fiber determines the bulk, texture,

luster and hand of the fiber thus influencing the end use for the fabric.

Contd… Fibres with crimp, non round cross section and twist scatter

light and so tend to mask carpet soiling. Round fibres such as wool, result in bulkier fabrics because

they do not pack as much as flat fibres like cotton. Round shaped rod fibres like nylon offer smoother more

slippery hand than wool which has round shape but scaly surface.

Fibre Surface and Diameter They may be smooth, rough, slightly grooved, deeply

channeled or wrinkled. For eg: wool – scaly, cotton – smooth, rayon – serrated. Diameter refers to the thickness of the fiber. Thicker fibers results in greater stiffness, which improves

wrinkle resistance but can also result in undesirable roughness. Large diameter fibers result in bulkier fabrics. Fine diameter fibers result in sheer, lightweight, more

drapable, softer to touch fabric.

Fibre longitudinal configuration Lengthwise fibres have varying configurations. May be straight, twisted, coiled or crimped. Cotton fibre – naturally twisted whereas nylon – straight. Performance properties such as resiliency, elasticity and

abrasion resistance are affected by fibre longitudinal configuration.

Fibre Performance Properties It determines the behavior characteristics of fibers and thus

their suitability in specific end use conditions.

Aesthetics – properties relating to visual effects as well as those perceived by touch.

Flexibility, Hand, Luster, Pilling, Resiliency, Thermo plasticity

Durability – properties relating to resistance to wear and destruction in use.

Strength, Abrasion Resistance, Chemical effects, environmental conditions.

Contd… Comfort – properties relating to physical comfort. Absorbency, Cover, Elasticity, Wicking.

Safety - properties relating to danger or risk of injury. Flammability, resistant to chemicals.

Durability Properties: ABRASION RESISTANCE – ability to resist wear from

rubbing that contributes to fabric durability

STRENGTH – ability to withstand stress. Fiber strength, the force needed to break the fiber is known as tenacity and expressed in grams per denier.

CHEMICAL RESISTANCE

ENVIRONMENTAL CONDITIONS How fibers react to certain exposure or storage.

For example….. Wool garments need to be mothproofed when stored.

Nylon and Silk show strength losses from extended exposure to sunlight.

Cotton has poor resistance to mildew and not allowed to remain wet.

COMFORT PROPERTIES: COVER – ability to occupy an area. A thick fiber or one with

crimp or curl gives better cover than thin straight fiber.

ELASTICITY – ability to increase in length when under tension and then return to the original length when released.

ABORBENCY – ability to take in moisture.

expressed as percentage of moisture regain which is the amount of water a bone-dry fiber absorbs from the air under standard conditions of 21ºC and 65%

Hydrophilic and Hydrophobic fibres.

Contd .. WICKING – ability of fiber to transfer moisture from one

section to another. Usually the moisture is along the fiber surface, but it also pass through the fiber when a liquid is absorbed by the fiber.

It is based on the physical and chemical composition of fibre.

Smooth surface reduces wicking action.

Some hydrophilic fibres like cotton, some hydrophobic fibres like olefin have good wicking property when micro denier in size.

Safety FLAMMABILITY – ability to ignite or burn. Important

characteristic because people’s lives are surrounded with various textile products.

Classification based on flammability: Flammable fibers – easy to ignite and sustain combustion.

Flame resistant fibres - relatively high ignition temperature and slow rate of burning. They may be self extinguishing.

Flame proof fibres – will not burn

AESTHETIC PROPERTIES: FLEXIBILTY – capability of fiber to bend easily and

repeatedly without breaking.

Eg. Flexible fibre like acetate – highly drapable fabric and garment.

HAND – Way a fiber, yarn or fabric feels when handled.

Decided by its shape, surface and configuration.

LUSTRE – refers to light reflected from surface. Increased lustre from smooth, less crimp, flatter cross-sectional shape and longer fiber length.

Contd… PILLING – Formation of groups of short or broken fibers on

the surface of fabric that are tangled together in the shape of tiny ball. Its an undesirable property.

Hydrophobic fibers tend to pill more than hydrophilic fibers.

RESILIENCY – Capability of the material to spring back to shape after being creased, twisted or distrorted and closely related to wrinkle recovery.

Polyester has outstanding resiliency whereas cotton has poor resiliency.

Contd… STATIC ELECTRICITY – frictional electric charge caused by

rubbing together of two dissimilar materials.

THERMOPLASTICITY – ability of fibers to withstand heat exposure. A thermoplastic fibre softens when heat is applied and may melt to liquid state when higher heat is applied.

Burning Characteristics of fibres

Chemical Solubility test for fibres