Lignocellulosic fibers chemical composition

Rowell, R.M., Cleary, B.A., Rowell, J.S., Clemons, C. and Young, R.A. (1993b). Results of chemical modification of lignocellulosic fibers for use in composites. In Wood Fiber/Polymer Composites Fundamental Concepts, Processes, and Material Options, Wolcott, M.P. (Ed.). Eorest Products Society, Madison, Wiseconsin, USA, pp. 121-127. 

Chemical Modification of Lignocellulosic Fibers To Produce High-Performance Composites... 

Lignocellulosics are three-dimensional, polymeric composites made up primarily of cellulose, hemicelluloses, and lignin. Table 1 shows the chemical composition of several different types of natural fibers. It is interesting to... 

GENERAL PROPERTIES OF LIGNOCELLULOSIC FIBER AS FILLERS Chemical Composition... 

In this chapter we have reviewed some of the most important characteristics of cellulose and cellulose based blends, composites and nanocomposites. The intrinsic properties of cellulose such as its remarkable mechanical properties have promoted its use as a reinforcement material for different composites. It has been showed that cellulose is a material with a defined hierarchy that tends to form fibrillar elements such as elementary fibrils, micro fibrils, and macro fibers. Physical and chemical processes allow us to obtain different scale cellulose reinforcements. Macro fibers, such as lignocellulosic fibers of sisal, jute, cabuya, etc. are used for the production of composites, whereas nano-sized fibers, such as whiskers or bacterial cellulose fibers are used to produce nanocomposites. Given that cellulose can be used to obtain macro- and nano-reinforcements, it can be used as raw material for the production of several composites and nanocomposites with many different applications. The understanding of the characteristics and properties of cellulose is important for the development of novel composites and nanocomposites with new applications. 

Ashori et al. [58] used recycled PP and HDPE as matrices for lignocellulosic fiber composite using MAPP as coupling agent. This composite has been used for board preparation. Ardanuy et al. [59] prepared recycled polypropylene-based green foams reinforced with untreated and chemically treated cellulose fibers obtained from agricultural residue. Their results showed that these foams may find potential... 

It is important to mention that the chemical composition of each type of fibers and the orientation of microfibrils about the fiber axis, called microfibrillar angle (Table 8.1), may significantly differ. Similarly, depending on the cellulose and lignin contents, crystallinity index of each type of fiber differs. In view of these, when lignocellulosic fibers are tested for their tensile properties, their fracture mode differs, which may be intercellular or intracellular or mixed modes of fracture. Accordingly, the tensile properties and fractographs are different for each type of fiber. These are also listed for some fibers in Table 8.1 and Fig. 8.3, respectively. 

The work of Valadez-Gonzalez et al. [37] was the only study reported so far to compare two methods, the SFP and the SFF, using a lignocellulosic fiber. In their work, the IFSS of henequen fibers embedded in polyethylene was separately evaluated by means of both SFP and SFF tests. The fibers were previously subjected to different surface chemical treatments aiming at improving the fiber/matrix adhesion. Table 9.3 shows the probable results obtained as a composition of Fig. 11 and Table 4 of Valadez-Gonzalez et al. [37] article. 

Lignocellulosic Natural Fibers Structure, Chemical Composition and Properties... 

Chapters 15-18 focus on the weathering/mechanical study of lignocellulosic fiber-reinforced polymer composites. The effect of different environmental conditions on the physico-chemical and mechanical properties of the polymer composites is discussed in detail in these chapters. Chapter 15 mainly focuses on the effect of weathering conditions on the properties of lignocellulosic polymer composites. Most of the focus of this chapter is the effect of UV radiation on different properties of composites. Chapter 16 describes the effect of layering pattern on the physical, mechanical and acoustic properties of luffa/coir fiber-reinforced epoxy novolac hybrid composites, and Chapter 17 summarizes the fracture mechanism of wood plastic composites. Chapter 18 focuses on the mechanical behavior of biocomposites xmder different environmental conditions. 

Various treatment methods onto oil palm fibers are already discussed in detail [22, 23, 45-47] including a detailed discussion on various treatments on lignocellulosic fibers in general to improve their properties [48]. Reviews on the developments in chemical modification and characterization of natural fiber-reinforced composites... 

Like all the lignocellulosic fibers, the physical and chemical properties of jute fiber is also dependent on the three chemical components, viz., cellulose, hemicellulose and lignin. The chemical composition and structural parameters of jute fibers are represented in Table 20.3. 

The amount of cellulose in lignocellulosic systems, can vary depending on the species and age of the plant. Table 21.1 shows the chemical composition of some common natural plant fibers. 

Applications of Kenaf-Lignocellulosic Fiber in Polymer Blends 503 Table 22.2 Chemical composition of some common natural fibers [7, 11],... 

Besides, they also greatly differ in terms of chemical compositions. It has been reported that their chemical components vary according to their different cultivate, years, climates and soil conditions [30]. It is a fibrous plant consisting of an inner core fiber (60-75%) and an outer bast fiber (25-40%) in the stem [31]. As previously mentioned, lignocellulose material from wood or non-wood plants consists of cellulose. 

There are undoubtedly numerous chemical pre-treatment methods used in the literature for the isolation of cellulose fibers from different lignocellulosic sources. The choice of these chemical treatment methods is influenced by the properties of lignocellulosic materials such as their chemical composition, internal fiber stmc-ture, microfibril structure, microfibril angle, cell dimensions and the defects which are in return influenced by the type and the sources of the lignocellulosic materials (Siqueira et al., 2010). The intended use of the cellulosic fiber product could also have an influence on the choice of chemical treatment method (Dufresne et al., 2008). The schematic diagram showing different pre-treatment methods during cellulose isolation are depicted in (Fig 3.11). 

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