**2. Compositions and natural Fibers properties**

To acquire a thorough grasp of the degrading issues, it is vital to first fathom the nature and compositions of NFr. NFr are categorized according to whether they

**Figure 1.** *Schematic representation of structure of natural fiber.*

originated from plants, animals, or minerals. The major component of NFr generated from plants is cellulose fibrils embedded in lignin matrix. **Figure 1** demonstrates the structure of a biofiber. Three secondary cell walls and a primary cell wall make up the complicated layered structure of each fiber. The thick middle layer of secondary cell walls governs the mechanical characteristics of fiber. It is composed of a series of helical microfibrils generated from long-chain cellulose molecules. Each cell wall consists of three primary elements: cellulose, hemicelluloses, and lignin. Lignin-hemicelluloses serve as the matrix, whereas microfibrils (composed of cellulose molecules) serve as the fibers [20, 21]. Other constituents consist of pectins, oil, and waxes [21, 22]. The most important structural element of many NFr is cellulose, a natural polymer with three hydroxyl groups per repeating unit. Cellulose is resistant to hydrlolysis, strong alkali and oxidizing agents. However, when exposed to chemical and solution treatments, cellulose degrades to some extent. Hemicelluloses are polysaccharides with a reduced molecular weight that act as a cementing matrix between cellulose microfibrils and are the fundamental structural component of the fiber cell. Because it is hydrophilic, weak acids and bases can quickly hydrolyze it. Lignin is a complex hydrocarbon polymer that provides plants their stiffness and aids in water transport. It is hydrophobic, resistant to acid hydrolysis and the assaults of most microbes, soluble in hot alkali, rapidly oxidized, and readily condensable with phenol [23].
