Textile fibers | Physical properties | Performance properties

Textile fibers | Physical properties | Performance properties

            Textile fibers are the flexible material composed of polymer chains made of molecules and are identified usually in terms of high length to low width ratio. Fibers are classified into Natural, Regenerated and Man-made.

Natural fibers are grown or cultivated or extracted. Grown natural fibers are exist from vegetable plants. Cultivated fibers are from animal source and Extracted fibers are from Mineral Materials.

Examples of fibers classified as vegetable fibers are Cotton, Jute, Hemp, etc.

Examples of fibers classified as animal fibers are Silk, Wool, etc.

Example of fibers classified as Mineral is asbestos.

            Regenerated fibers are a modified form of natural fibers. Examples of fibers modified based on cotton (Cellulosic) are Rayon, Viscose, Acetate, Tencel, Lyocel,modal,etc.

            Man-made fibers as drawn synthetically as per requirements. Examples of fibers in vogue are Polyester, Nylon, Acrylic, etc.

Fibers used for textile material end use should possess below prime properties.

1.      High Length to Width Ratio

2.      Surface Cohesiveness

3.      Tenacity

4.      Flexibility

5.      Uniformity

High Length to Width Ratio is the physical measurement indicator of fiber. The length should be minimum 100 times more than its width. This ratio in cotton is around 1400 and silk is around 33 x 10 to the power 6.

Surface Cohesiveness is the natural characteristics of fiber to hold one and each other when spun and gives strength to the yarn. This property of fiber will influence on yarn strength as well as its uniformity.

Tenacity of the fiber is the important property indicating the strength of fiber. This tenacity value will differ from fiber to fiber types. Adequate tenacity of the fiber will provide better durability of the end use.Cotton has 3.0 to 5.0 grams of force per denier(gf/d),Wool has 1.0 to 1.7 gf/d, polyester has 2.5 to 6.3 gf/d, nylon has 4.3 to 9.0 gf/d and Rayon has 2.4 to 3.0 gf/d.

Flexibility is the bending property of the fiber playing an important role in comfort to the fabri wear as well as gives better drapability.

Uniformity is pertaining to the shape of the fiber that considers the cross sectional area and longitudinal area of the fiber. The cross section of the fibers may vary from one fiber end to other end. Due to this non-uniform cross sectional areas, the resulted shape may affect the dye uniformity by poor dye fiber affinity. To give uniformity to the fiber, mercerisation process is applied with caustic soda.

Other fiber properties considered to define textile fibers are briefed are listed and briefed below are. These properties will decide with performance of the finished fabric

1.      Physical Shape

2.      Density

3.      Luster

4.      Color

5.      Moisture Regain

6.      Elastic Recovery and Elongation

7.      Resiliency

8.      Flammability

Physical shape : As discussed in the prime properties will play an major role in fabric performance especially in fabric drape, aesthetic, shade consistency as well as strength properties of the finished fabric or end use. Different fiber types have different shapes in cross sectional area apart from their longitudinal appearance. Natural fibers like cotton, wool, jute, silk etc possess their own shapes decided by their nature of their growth while the shape of man-made fibers like polyester,nylon,aramid,acrylic,are manipulated in manufacturing process. Now in the era of  21 cetury,we started to use the modified cellulosic fibers with different petent names and trademarks like Viscose,Rayon,Excel,Tencel,modal,etc…The content of these modified regenerated fibers and natural cotton is same that is ‘’Cellulose’’ but only difference is in the morphology of the fobers.The modification in the morphology is done based on the requirments which suits contemporary fashion trends as well as considering the need of comfort.

Density: Every earthly particle of this world have their own density. Without density no material will appear on this earth. Density is the mass of the material weighs per unit area.All chemical elements found on this earth have their own density. The density is influenced by gravity when the material is on earth. Though the textile fiber is small in size and weight must have density. The density of the textile fiber influence the factors like dye fiber affinity, weight of the finished fabric and comfort of the fabric wearer. And main understanding of this fibe density lies in giving functional performance to the sportswear , active wear and outer wear fabrics.The unit of measurement of fiber density is ‘’Grams per Cubic Centi Meter’’. Natural fibers like Cotton has 1.54 to 1.56 ,Wool has 1.30 to 1.32,Silk has 1.25 to 1.34 while manmde fibers like Polyester has 1.23 to 1.38,Nylon has 1.14 and Spandex has 1.20 to 1.25.

Luster:The word Luster indicate the shininess of the material that is in this case Its Luster of Fiber.The shininess ,semi dullness and dullness in appearance of fiber will directly influence the appearance of the finished fabric. Natural fibers have their own surface appearance and its depends on the surrounding environments where they have been grown or cultivated. But The shininess can be incorporate in man-made synthetic filament fiber based on the requirement. Fabrics need luster level depends on end use used specially for outerwear, casual wear, party wear, etc

Color: The luster defines the shininess of the fiber, whereas color defines the fiber’s visual outcome belongs to which VIBGYOR line..that is Red,Blue,Green,.etc,. Natural cotton fibers possess their own natural colors like off white cotton, bluish cotton and yellowish cotton.Wool has its own shades depends on its origin. Silk has its own shades based on silk work and sericulture done. But color of the synthetics are not decided while manufacturing, instead will be preferred to finish in white only by keep in view of dyed it in required colors.Though the visual shades of the fibers are natural or white but spun grey yarn or woven grey fabric from those fibers are subjected to wet process to bring them to the status of ‘’Prepared for Dyeing’’ before the spun yarn or woven fabric taken for dye to the required colors.But in some natural fibers cases like Jutes,Hemp,Flex,Linen,Wool etc, their natural shades are dominated though they spun into yarn or woven into fabric.

Moisture Regain and Moisture Absorption: One of the important property required for textile fiber is characteristics of absorbing moisture and its regain. This property will help the textile fiber to cooperate in wet processing. If fiber does not have absorbing character, no liquid chemical penetrate into the surface of the fiber and dye fiber affinity will be not there. For Dyeing of the yarn or fabric involves many stages of wet processing. Wet processing needs the core fiber to absorb wet particles. Particle may be any chemical or it may be color. The absorbency of fiber in turn depends on its morphology that is its internal chemistry.The whole wet processing of textiles depends on morphology of fibers.We will discuss about fiber morphology later in dyeing technology. Here we can say the percentage of air space available inside the fiber chemistry will decide the dyeability of the fiber.This available air space will be taken into consideration to judge the absorption capability of the fiber.

            Moisture absorption is the ability of the fiber to absorb surrounding moist during particular time.  Moisture regain is the ability of the fiber to have required moist.Here the moist is water particle. Both Moisture absorption and moisture regain are measured in terms of percentage of oven dry weight of the fiber.The lab will calculate the percentage by measuring weight of the fiber at oven dry condition and by measuring the fiber weight after 48 hours of lab conditioning that is with 23’C Temp and +/-65% Relative humidity. The percentage resulted with the initial weight from the difference between oven dry weight & conditioned weight will indicate the ability of the fiber to absorb.[ give % of different fibers].The testing of moisture absorbency will help in deciding the dye ability of the fibers.

Elastic Recovery and Elongation: Textile fibers are flexible in nature and should have property of elongate and recover when subjected to stress and strain. The fibers and yarns in the garment are subjected to stress and strain while body is in movement. Due to this the chances of fibers gets elongate to its capable extent when strain is caused and attaint its original state when strain is released. If the fiber does not have this quality of elongation and attaining back, then fiber rupture can takes place.  Such fibers cannot be used for production of cloth for garment end use.

            Fibers getting elongate from its original size to its capable extent when applied tension is measured in terms of ‘’Percentage of Elongation’’ .Like that, the ability of fibers attaining back to its original state is expressed as Elastic recovery and measured in terms of ‘’Percentage of Recovery’’ [ give % of different fibers].Elastic recovery and elongation also influence the strength characteristics of the yarns and fabrics. That is the tear strength and tensile strength of the fabric. This will be discussed in textile testing part.

Resiliency: This is the state of the fiber attained its complete rest position when tension is removed and cannot recover further or elongate further.All textile fibers should have this character and its part of property of elongation and recovery. Dimensional stability of the fabric is measured based on this resilience character. Fibers, yarns and fabrics are subjected to many stress and strains from spinning to wet processing of fabrics. When fabric reached its finishing stage,the fabric is  passed through Sanforization treatment in the mill. That is making the fabric dimensionally stable.Making the fabric stretch and shrunk will makes the fibers attain their rest position as well as reduce the yarns elongation.This will result in controlled shrinkage rate.

            Why natural fiber fabrics shrunk more compared to man-made fiber fabrics ?.The reason is the morphology of the man-made fibers are controlled manually ,so the fabrics are stable, as the morphology of natural fibers are varying and need additional applications.

Flammability: Flammability is also the essential property for the garments, especially for the end uses which are need to wear by workmen who work in the industries at floor, who involved in extinguishing of fire and areas where chances of fire expected. Flammability of the textile fibers  or fabrics is an risk factor while considering for end use.The behaviour of fibers when comes in contact with the fire as well as the duration of withstanding the fire are varying from fiber to fiber. Some fibers catch fire immediately, some fibers takes time to burn, some fibers melt & lose the shape.Some fibers gets fire even at higher surrounding temperature.If fibers are flammable but need for end use, then its required to apply the finish’’Fire Proof’’ or ‘Fire Retardant’’ to the fabrics. Complete fire proof is difficult but fire retardant is feasible to increase the fire resisting time.This fire resisting time of fabric will help victim to come out from the risk.  So this flammability test is made mandatory by many global brands.