A Brief Discussion on Several Basic Properties of Textile Fibers
1. Moisture Absorption Properties Of Fiber
Textile fibers, when placed in the air, continuously exchange moisture with the surrounding environment. This means that textile fibers constantly absorb moisture from the air while also releasing moisture back into the air. The ability of textile fibers to absorb or release moisture is referred to as their moisture absorption properties. This property is one of the important physical characteristics of textile fibers.
The degree of moisture absorption in textile fibers affects their shape, size, weight, and physical-mechanical properties, which in turn impacts their processing and usability. Moreover, the moisture absorption capacity directly influences the wearing comfort of the fabric. Fibers with high moisture absorption capabilities readily absorb sweat produced by the body, help regulate body temperature, and alleviate the feeling of dampness, making the wearer feel comfortable. Therefore, attention to moisture absorption properties is crucial in commercial trade, fiber performance testing, textile processing, and the selection of textiles.
Among common textile fibers, wool, linen, viscose fibers, silk, and cotton have relatively strong moisture absorption capabilities, while synthetic fibers generally have poor moisture absorption. Among them, modal and nylon exhibit slightly better moisture absorption, while acrylic is inferior; polyester is even worse, and polypropylene and chlorofiber are almost non-absorbent.
Currently, it is common practice to blend synthetic fibers with poor moisture absorption capabilities with natural fibers or viscose fibers that have stronger moisture absorption to improve the moisture-wicking ability of textiles.
In terms of fiber moisture performance, besides moisture absorption, the water absorption characteristics of fiber materials are also closely related to the wearing comfort of the fabric. Water absorption refers to the ability of fibers to take up liquid water.
2. Mechanical Properties of Fibers
The performance of textile fibers under various external forces is referred to as the mechanical properties of textile fibers. External forces include various forms of stretching, compression, bending, twisting, and friction.
The mechanical properties of textile fibers include the strength, elongation, elasticity, wear resistance, and elastic modulus of the fibers.
Fiber Strength: The strength of a fiber refers to its ability to resist damage from external forces, which largely determines the durability of textile products.
Wear Resistance of Fibers: Fibers and their products experience wear due to constant friction during processing and actual use. The wear resistance of fibers refers to their ability to withstand external wear. This property is closely related to the durability of textile products. The level of wear resistance is an important indicator of the performance of fabrics for clothing. Fiber wear resistance is influenced by factors such as the macromolecular structure, supramolecular structure, breaking elongation, and elasticity of the fibers.
The common order of wear resistance for different fibers is as follows: Nylon > polypropylene > modal > polyethylene > polyester > acrylic > chlorofiber > wool > silk > cotton > linen > Tencel > cupro > viscose fibers > acetate fibers > glass fibers.
3. Chemical Resistance of Fibers
The chemical resistance of fibers refers to their ability to withstand damage from various chemical substances.Fibers in textile dyeing and finishing processes come into contact with water, acids, alkalis, salts, and various other chemical substances to varying degrees. Additionally, during use, fiber products are also exposed to various chemicals such as detergents and finishing agents. Therefore, textile fibers must possess a certain level of chemical resistance to meet the requirements of dyeing and finishing processes as well as product usage.
Furthermore, understanding the chemical resistance of various textile fibers allows for the appropriate selection of processing conditions and the correct use of different fiber products. Among the various textile fibers, cellulose fibers exhibit strong resistance to alkalis but weak resistance to acids. In contrast, the chemical resistance of protein fibers differs from that of cellulose fibers; they are more resistant to acids than to alkalis. Protein fibers can be damaged to varying extents in both strong and weak alkali environments, potentially leading to decomposition. Synthetic fibers generally show greater chemical resistance than natural fibers; for example, polypropylene and chlorofiber exhibit excellent resistance to acids and alkalis.
4. Linear Density and Length of Fibers and Yarns
The linear density of a fiber refers to its thickness, while the length of a fiber indicates its elongation. Textile fibers must possess a certain linear density and length to ensure that they adhere to one another and rely on the friction between fibers to be spun into yarn. Therefore, having an appropriate linear density and length is one of the necessary conditions for textile processing and for giving products practical value.
The linear density of textile fibers is closely related to the performance of yarns and fabrics produced during textile processing. In general, fibers with lower linear density and better uniformity facilitate textile processing and improve product quality. In terms of the impact of fiber linear density on fabric performance, fabrics made from finer fibers tend to be softer and have a milder sheen, allowing for the creation of lightweight textiles. They can also be used to manufacture breathable fabrics with a silk-like effect. However, fabrics made from fine fibers are more prone to pilling and fuzzing, while coarse fiber fabrics can be utilized to create stiff, rugged, and substantial textiles.
Similarly, the length of textile fibers is closely linked to the quality of textile products. Longer fibers with good length uniformity and lower short fiber content are advantageous for textile processing and product quality. Under the same conditions, longer fibers result in stronger yarn with more uniform slubbing and a smooth surface, leading to fabrics that are durable and visually appealing while being less prone to fuzzing and pilling. Furthermore, provided a certain yarn quality is maintained, longer fibers allow for finer yarns to be spun, suitable for creating lightweight textiles. For shorter fibers, length is often more critical than linear density; for example, length is the most important criterion for cotton grading and pricing.
In textile fibers, natural fibers exhibit variability in linear density and length, often with significant differences that depend on fiber type and growth conditions. In contrast, chemical fibers are artificially manufactured, and their linear density and length can be controlled and specified within a certain range according to processing and use requirements.
Bulk yarn is first spun from a blend of two fibers with different shrinkage rates, which is then treated in steam, hot air, or boiling water. At this point, the fiber with a higher shrinkage rate contracts significantly and is positioned at the center of the yarn, while the lower shrinkage fibers are pressed to the surface, forming loops. This process yields a fluffy, plump, and elastic bulk yarn.
The linear density is one of the important physical properties and geometric characteristics of fibers. It not only affects textile processing and product quality but is also closely related to the performance of the fabric. Similarly, linear density is one of the most important indicators for yarns, as it influences the physical-mechanical properties, hand feel, style, and other aspects of textiles. It is also an important basis for fabric design.
There are various representations of the linear density of fibers and yarns. Typically, indirect indicators proportional to the cross-sectional area of the yarn are used, with commonly used metrics including tex, metric count, imperial count, and denier.
5. Characteristics of Common Fibers
(1) Natural Fibers:
COTTON: Absorbent, soft.
LINEN : Wrinkles easily; crisp and breathable after processing; relatively high price.
RAMIE : A type of linen, coarse yarn; typically used for curtains or upholstery; if used for clothing, often blended with linen.
WOOL : Fine yarn, resistant to pilling.
LAMBSWOOL : Coarser yarn, usually blended with acrylic to prevent deformation of garments.
MOHAIR : Fluffy texture, warm.
CASHMERE : Fine fibers, lightweight, soft, and comfortable to touch.
ANGORA : Fine, loose yarn; smooth feel and elastic, relatively high price.
SILK : Soft, beautiful sheen, highly absorbent.
(2) Chemical Fibers:
RAYON : Very light and soft, often used for shirts in collections.
POLYESTER : Similar to rayon, easy to handle, wrinkle-resistant after ironing, and relatively inexpensive.
SPANDEX : Naturally elastic; typically blended with cotton fabrics, requiring only 5% to 10% to provide significant elasticity, preventing deformation and fading; relatively high price.
NYLON : Completely non-breathable, stiff feel; suitable for windbreakers; when blended with wool, it adds structure to garments.
