Fibrous plants

Gram negative bacteria are natural contaminants of fibrous plant material. In processes where cotton is agitated, i.e. during rapid machining, bacteria on the cotton fibers often become airborne, and the workers involved in dus areas may be exposed to concentrations of bacteria as high as 10 bacteria/m 51). 

Cellulose powder is a mechanically shortened cellulosic fiber, whereby the degree of polymerization remains almost intact. Microcrystalline cellulose is a partially purified and depolymerized cellulose, prepared by treating a-cellulose obtained from fibrous plant material with mineral acids. It occurs as a fine white odorless and... 

Occurs in all plants as a constituent of cell walls as structural component of woody and fibrous plants. 

Folklore The name urtica is believed to be derived from the Latin verb urere , to bum, most probably referring to the stinging action of the plant. Nettle is a fibrous plant and was used in cloth manufacture from the Bronze Age until the early twentieth century. The fresh young plant tops have been cooked as a spinach-like vegetable dish, and used to be brewed into a nettle beer in certain parts of the United Kingdom. The herb was known as a blood purifier which, in current terms, is a detox herb. The herb has a high chlorophyll content and has been used as a source for extraction of this natural colour (Bown, 2003 British Herbal Medicine Association, 1983 Graenwald et al, 2002 Hutchens, 1973 Shealy, 1998 Tierra, 1998). 

Cellulose Gel occurs as a fine, white or almost white powder. It is purified, partially depolymerized cellulose prepared by treating a// /za-ccllulose, obtained as a pulp from fibrous plant material, with mineral acids. It consists of free-flowing, nonfi-brous particles that may be compressed into self-binding tablets that disintegrate rapidly in water. It is insoluble in water, in dilute acids, in dilute sodium hydroxide solutions, and in most organic solvents. 

These minerals were ground into fine powders then mixed with a resin, such as pine pitch. An oil base was sometimes added by grinding certain seeds or extracted from animal fat. Paints were applied either by fingers or with brushes made from the shredded end of a stick, animal fur, or fibrous plant leaves. 

Microcrystalline cellulose is manufactured by controlled hydrolysis with dilute mineral acid solutions of a-cellulose, obtained as a pulp from fibrous plant materials. Following hydrolysis, the hydrocellulose is purified by filtration and the aqueous slurry is spray-dried to form dry, porous particles of a broad size distribution. 

Powdered cellulose is manufactured by the purification and mechanical size reduction of a-cellulose obtained as a pulp from fibrous plant materials. 

Avicels (either original, regenerated, ethylenediamine (EDA)-treated, or mercerized) are 100% soluble linters and mercerized linters are about 32%i soluble. High DP fibrous plant celluloses are soluble only up to 37%i even after swelling treatments. 

Fibrous plants can be classified from their purpose point of view. In this classification system, bast fibers are classified into group of fibrous plants cultivated just for fiber production. The second group of the system contains plants grown for other goods, for example, fruits - coconut production, and fibers constitutes only a by-product of the plant - coir (Pickering 2008). Another classification system indicates that most of the technically important bast fibers are obtained not only from plants cultivated in agriculture, such as flax, hemp, or ramie, but also from wild plants, such as nettle. 

Bast fiber is extracted from phloem surrounding the stem of fibrous plants, mainly dicotyledonous ones. Figure 4.4 presents cross section of fibrous plant stem. Bark or skin protects the plant against moisture evaporation, sudden temperature changes, as well as partly gives mechanical reinforcement to the stem. Fibers are located in the phloem and occur usually in bundles under the skin they support the conductive... 

Fig. 4.4 Image of cross-section of fibrous plant (flax) stem (Place wlasne INFMP)...

Fibrous plant Phloon content in dry straw (%) Fiber ctmtent in phloem (%) Fiber content in dry straw (%)... 

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. 

There are many reports in scientific literature that present data determining physical-mechanical properties of bast fibers. The properties of the fiber are related to varieties of fibrous plants, condition of cultivation and retting, as well as the condition of measurement. Natural fibers are also characterized by the variability of individuals and from these reasons it is possible to find some differences between the fiber properties given by different authors in literature. 

The composite materials reinforced with natural fibers will stimulate agriculture by the production of nonfood raw materials for the industry (Bledzki 1997) and by achieving high yields of raw materials derived from fibrous plants, thus leading to improvement in total yields of crops. 

Another strong aspect of vegetable fiber application in the industry is their ecological character with possibility of carbon dioxide reduction from the atmosphere during the fibrous plants cultivation processes. Use of bast fibers ensures biodegradability of the end product, if natural polymer, e.g., PLA is applied as a matrix. 

Kozolowski R, Rawluk M, Barriga J (2004) Stale of the art-production, processing and applications of fibrous plants. In Proceedings of 2nd international conference on textiles... 

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. 

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