Vegetable fibers, chemical composition

Okra, Hibiscus escuentus L. The immature pods of okra are popular as a vegetable and okra is also used for the ability to thicken soups and stews, and for fiber and oil. Notmuch is known about okra most workers concentrate their research on the chemical composition (26-29) of the mucilaginous materials found in the pod (30) stalk, nutritional properties (31). Research has also been conducted on the developmental properties of the okra seed (32). This paper is the first report of the chemical composition of auxin conjugates in okra pods bound to nitrocellulose membrane. 

Because of the immense importance in usefully exploiting the fibers in a vast variety of end-uses, the chemical composition of vegetable fibers attracted the attention of many investigators in the past. Consequently, it is generally agreed that vegetable fibers contain one or more (usually more) of the following [173] ... 

Chemical composition of bast fibers is presented in Table 4.3. Cellulose is the main component of vegetable fibers. The elementary unit of the macromolecule is anhydro o-glucose, containing three hydroxyl groups, which form hydrogen bonds... 

Table 17.1 presents the chemical composition of different vegetable fibers. Compared to the other fibers, wheat straw shows rather low cellulose content, a high lignin composition, but also a high ash content linked to a high silica fraction. Silica is mainly located on the leaves, 12% of ash in the leaves compared to, for example, 6% in the intemodes. Average value is 7-8% of ash in the straw. 

Cellulose-Based Polymers for Packaging Applications 483 Table 21.1 Chemical composition of some common natural vegetable fibers. 

Vegetable and animal oils can be made more chemically reactive (eg, by epoxidation), and then cross-linked to form sturdy thermosets. Reinforced with glass fiber the composites have applications in the areas of agricultural equipment and the automotive industry. Plant fiber reinforcement, eg, from jute, hemp, flax, sisal, keraf, wood, straw, or hay, provides a biodegradable option (73). 

In addition to conventional vegetal cellulose fibers (Figure 1 A), other forms of cellulose have been assessed in the last few years. The use of micro and nano-cellulose fibers, namely whiskers, obtained from a marine species (Samir, 2005), bacterial cellulose produced by some bacterial strains (Pecoraro, 2008) as well as micro- or nano-fibrillated cellulose prepared by mechanical, enzymatic or chemical treatments of the vegetal fibers (Nakagaito, 2004), for the development of high performance composite materials is attracting researchers from diverse fields (Dufresne, 2008 Lee, 2009), as the addition of very modest amounts of nano fibers leads to new composite materials with superior mechanical properties and new functionalities (Klemm, 2009) when compared with their conventional cellulose fibers counterparts. 

Natural fibers can be classified according to their source vegetable, animal or mineral. In particular, vegetable fibers consist basically of cellulose, hemicellulose, lignin, and other amorphous constituents, in smaller amounts, and due to their chemical composition they are also known as lignocellulosic fibers [21],... 

Mohanty AK, Parija S, Misra M (1996) Ce(IV)-A(-acetylglycine initiated graft copolymerization of acrylonitrile onto chemically modified pineapple leaf fibers. J Appl Polym Sci 60 931-937 Mohanty AK, Khan MA, Hinrichsen G (2000) Surface modification of jute and its influence on performance ofbiodegradable jute-fabric/Biopol composites. Compos Sci Technol 60 1115-1124 Mohanty AK, Misra M, Drzal LT, Selke SE, Harte BR, Hinrichsen G (2005) Natural fibers, biopolymers and biocomposites an introduction. In Mohanty AK, Misra M, Drzal LT (eds) Natural fibers, biopolymers and biocomposites. Taylor Francis, FL, Boca Raton Mukherjee PS, Satyanarayana KG (1986) Structure and properties of some vegetable fibres Part 2 pineapple fiber. J Mater Sci 21 51-56... 

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