In the previous article, we mentioned that cotton, linen, and jute are made up of similar chemical components. However, the proportions of these components in different fiber types are different, resulting in distinct properties for each type.

1.Cellulose

The primary component of fibers. Natural cellulose containing impurities is white or light yellow and should be preserved as much as possible during the processing of natural fibers.

2.Pectin

Binds individual fibers into fiber bundles. Higher pectin content leads to thicker fibers. The colloid formed by pectin and hemicellulose often contains natural pigments. Fibers with high pectin content may exhibit yellow or brown-red hues.

3.Hemicellulose

Works alongside pectin to form a colloid that binds single fibers into bundles and anchors lignin to the fiber surface.

4.Lignin

Adds hardness and wear resistance to the fiber. Higher lignin content results in rougher fibers. Exposure to light can produce yellow pigment molecules over time.

5.Others (e.g., wax and mineral salts)

 Protect the cellular structure and maintain the life activities of plants.

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Now we analyse three kinds of natural fiber which have similar characteristics

Pineapple leaf fiber, banana fiber, and sisal fiber are natural fibers derived from plant leaves or stems (with banana fibers from leaves being weaker). These fibers share common characteristics: cellulose content below 60%, hemicellulose around 20%, and lignin approximately 10%. Their similar chemical compositions yield comparable properties. The higher hemicellulose content imparts excellent strength, hardness, and a significant elastic modulus, making objects like containers and ropes highly durable. However, the thicker fiber bundles make untreated fibers unsuitable for spinning high-count yarns. Additionally, a higher lignin content causes the fibers to darken over time, especially in bleached yarns or fibers, which transition from white to ivory and eventually to light yellow. This discoloration poses challenges for dyed fabric production.

The alkali treat process can effectively remove lignin and hemicellulose, softening the fibers—a process known as the "cellulose peeling reaction." Treating fibers with an alkaline hydrogen peroxide solution for 2-3 hours can remove over 80-90% of non-cellulose impurities, resulting in soft, white fibers. However, chemical treatment carries risks, including energy consumption and water pollution. Furthermore, cellulose may undergo hydrolysis in hot alkaline solutions, progressively weakening the fiber's strength during processing. Consequently, the treatment time and chemical dosage must account for factors such as material weight, bath ratio, impurity levels, and fiber maturity. The variability in crop quality, unlike the consistency of industrial products, further complicates precise degumming control. Excessive degumming can disassemble individual fibers from fiber bundles. These short fibers often end up in waste liquid during chemical processing or generate substantial dust during the cottonizing process, typically reducing yield by 15-30%.Therefore, the potential of this type of raw material needs to be further developed.