Plant fiber, elementary

Schematic structure of an elementary plant fiber (cell).

Since neither elementary fibrils, microfibrils, or larger structures are visible in untreated cotton or wood fibers, and because similar plant fibers treated in different ways and different fibers treated in similar ways have... 

The following ordered structures with decreasing diameter can be distinguished with fiber-forming plants fibers (0.06-0.28 mm), cell walls, macrofibrils (400 nm), microfibrils (20-30 nm), and elementary fibrils (3.5... 

At similar hydrolysis conditions, dimensions of the CNP depend on the origin of cellulose feedstock. In general, CNP derived from terrestrial plants (herbs, shrubs, crops, wood, bast fibers, cotton, etc.) have smaller sizes compared to those derived from other sources (tunicate, algae, and bacterial cellulose) this is in agreement with the lateral size of elementary crystallites (Habibi et al., 2010 Hanley et al., 1992 loelovich, 2014b Li and Ragauskas, 2011). 

Zylinski (1964) reported younger and finer fibers at the top of the plant, with thicker fibers near the bottom of the stem. Soluble components in flax fiber impact the hygroscopic moisture handling characteristics (Table 3.2). Foulk et al. (2003) reports that late harvest stems are less easily retted than those harvested before full maturity while estimating the percent fiber contributed to total plant weight by the pedicel to be 5% (Foulk et al. 2004). The plant stem has a diameter of 2-3 mm, which produces bast technical fibers with a diameter of 50-100 pm composed of elementary fibers (single plant cells) with a diameter... 

All parts of fibrous plant stem must be removed for proper fiber separation. Bast fiber extraction is usually conducted using special processes such as water and dew retting, degumming, or decortication, in which the separation of bundles craitaining elementary fibers joined together by pectin and calcium ions is also performed. Fiber content in the stem of fibrous plants is shown in Table 4.1. 

Figure 9.1. A. Fringe-fibril model of cellulose after Hearle [4] see also Zugenmaier [1], The right figure B. shows a schematic of a macro-fibril as existing in plant cells begin a composite of micro-fibrils. These consist of elementary fibrils which are made of 30-40 polymeric linear cellulose chains (picture based on the botany visual resource library [5]). The picture in figure A. is observed in crystalline cellulose, grown either artificially as for instance in textile fibers [1] or can be thought to mimic the structure of elementary fibrils.

Among all plant-derived fibers, cotton has the highest percentage of cellulose and is free of wooden particles. Relative to the water-free substance, the cellulose percentage of the fiber is about 95%. According to the elementary analysis of H. Mark (Mark, 1932), the cotton fiber contains... 

Table 11.2 shows the mechanical properties of natural (plant) and synthetic fibers [18]. Natural fibers are non abrasive towards mixing and molding equipment. This can contribute to significant equipment maintenance cost reductions. The elementary fibers are bound together by a pectin interphase. This interphase is much stronger than the interphase between the technical fibers [39]. Natural fibers are safe to handle and the working conditions are better when compared to synthetic reinforces, such as glass fibers. 

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