Nettle fibers

Some references distinguish between synthetic fibers nettle from synthetic polymers and those made by modification of cellulose (man-nettle fibers). 

Nettle fiber, 110 Neustrene 060, 668 Neutral axis, 226, 229, 231 Newtonian behavior, 619 Newtonian fluid, 619, 620, 626 Nexwood Red, 587... 

Bodros and Baley [37] studied the tensile properties of water retted nettle fibers. Bacci et al. [39] investigated fiber yield of nettle cultivation and quality of fibers extracted by alkalization. Bacci et al. [38] compared the effects of different fiber extraction method combinations including water retting, mechanical decortication and enzymatic treatments on resultant fibers chemical composition and tensile properties. Bajpai et al. [40,41] prepared nettle fiber-reinforced poly lactic acid (PLA) and PP composites by compression molding. Bajpai et al. [42] studied the effects of various environments on the tensile strength of nettle fiber-reinforced PP composites. 

Figure 11.4 Scheme of a scutcher designed and built for mechanical extraction of nettle fibers. (From L. Bacci et al Textile Research Journal, 2011 [38]. With permission from SAGE Publications). 

P.K. Bajpai, D. Meena, S. Vatsa, and I. Singh, Tensile behavior of nettle fiber composites exposed to various environments. /. Nat. Fibers 10,244-256 (2013). 

Natural fibers are basically derived from three natural resources, which are plants, animals, and minerals. Fibers from plants can be obtained from leaf (sisal fibers), bast (nettle fibers), seed (cotton), fruit (coconut) and wood (hard and softwood). Silk, wool and feathers are examples of animal fibers. Natural fibers from plants are widely used in fabrication of biocomposites for various applications [5]. 

Bodros, E, Baley, Ch. Study of Ihe fensile properties of stinging nettle fibers (Urtica... 

Scientists and engineers at the University of Exeter are investigating whether natural fibers tike hemp and sisal could be used to make sustainable and eco-friendly brake pads [39]. The technology of brake pads turned green with the replacement of asbestos by aramids (hke Kevlar of DuPont) in the 1980s. Kevlar is very expensive and eco-friendly alternatives like hemp, jute, sisal, nettle, and flax are much, much cheaper. A breakthrough in this application will revolutionize brake manufacture and protect the environment. 

Hemp rope, once widely used, has largely been replaced by iiylon cord. The flexibility and mechanical strength of hemp, a nettle plant fiber, also characterize nylon synthetic and several other inorganic fibers in common use. 

The family is essentially tropical with a few temperate species familiar as slinging nettles, which often produce painful sensations on contact with the leaves. Otherwise fibers (ramie) and a few edible leaves are known in the family. 

Nettles, J E, Handbook of Chemical Specialities Textile Fiber Processing, Preparation, and Bleaching, New York, John Wiley Sons, 1983. 

There are many kinds of natnral fibers, snch as bast fibers (flax, hemp, jute, kenaf, ramie, nettle, and mesta), leaf fibers (sisal, heneqnen, pineapple, abaca, oil palm, and screw pine), seed fibers (cotton), frnit fibers (coconnt hnsk, or coir), and stalk fibers (straw of varions kinds). They are not nsed for commercial WPG, primarily on economical reasons (except maybe Procell, see Table 1.1). Most of these fibers have fonnd applications in established indnstries, snch as textile indnstry (cotton, flax, jnte, ramie, hemp, and sisal) and paper indnstry (straw). 

Loading nose, 226, 232, 233, 236, 238, 239, 241, 242, 245, 253, 256, 265, 274 Long alkyl chain alkoxysilanes, 172 Long cellulose fiber, 79, 92, 98 Long natural fiber, 110 Abaca, 110 Bast fibers, 110 Cost of, no Cotton, 110 Flax, no Fruit fibers, 110 Hemp, no Henequen, 110 Jute, no Kenaf, 110 Leaf fibers, 110 Mesta, no Nettle, no Pineapple, 110 Ramie, 110 Seed fibers, 110 Sisal, no Stalk fibers, 110... 

Ramie belongs to the nettle family, genus Boehmeria nivea. The variety grown in China, Taiwan, and India has silvery-white hair on the underside of its leaves and yields China grass, or white ramie. The variety grown in Malaysia, Africa, and Mexico has leaves with green undersides and yields rhea, or green ramie. Strips from both are very similar, except that the white ramie fibers are considered to have a finer texture. 

Bast fibers - such as flax, hemp, kenaf, ramie, jute, and nettle... 

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. 

Properties related to bast fibers shape are shown in Table 4.4. Ramie, nettle, and flax are characterized by the highest density, but kenaf and isora show the lowest density. The longest technical fiber you can find is hemp, but ramie elementary fiber is the longest and the thickest. 

Chapters 2-10 discuss in detail the different properties of natural lignocellulosic fibers, their processing and fabrication of polymer composites. Chapter 11 summarizes the structure, chemistry and properties of different agro-residual fibers such as wheat straw corn stalk, cob and husks okra stem banana stem, leaf, bxmch reed stalk nettle pineapple leaf sugarcane oil palm bunch and coconut husk along with their processing. 

Faruk et al. [3] classify the plants, which produce natural fibers, into two groups according to their utilization primary and secondary. Primary plants are grown for their fiber, while secondary plants are grown for other causes where the fiber is a byproduct. Primary plants include jute, hemp, kenaf, and sisal, etc. Some conventional examples of secondary plants are pineapple, oil palm and coir. Some novel secondary plant examples include corn, okra, nettle, etc. This chapter is focused on these novel secondary plants, which give fiber as a by-product and have been the subject of limited research endeavor in the literature so far. 

Nettle (Urtica dioica L. or Girardinia diversifolia) is a perennial plant which is cultivated for food, fodder, cosmetics and medicine as well as for its fiber [37]. Although nettle... 

The advantages of nettle crop are the necessity of low agronomic inputs, suitability for organic farming, reduction of soil erosion and recovery of over-fertilized soils due to being a nitrophilous species [38]. Bacci et al. [39] obtained around 1700 kg ha fiber yield of nettle crop. 

Bacci et al. [39] treated nettle stalks with boiling soda solution xmtil the bark, the source of fiber, was easily removed from the core of the stalk than performed alkalization treatment on the bark. Enzymatical fiber retting maybe faster and more reproducible than the traditional biological fiber retting methods and is extensively studied for flax and hemp extraction enhancement [39]. 

De Rosa etal. [14] reported that the tensile tenacity and modulus of okra fibers presented a two-parameter Weibul distribution. They also reported a decrease in tensile tenacity and modulus with increase in okra fiber diameter, as Bodros and Baley [37] found for nettle stalk fibers. Having brittle structures, okra and nettle stalk fibers present straight stress-strain curves [14,37]. Mechanical properties of agro-residual fibers are listed in Table 11.3. 

Fiber quality and fiber yield is affected by fiber cultivar. For example the nettle clone bred by Bredeman had higher fiber content of 16% compared to that of wild nettle as 4-5% [39]. The chemical, physical and mechanical characteristics of fibers differ according to the portion of the plant they are extracted from. Bacci et al. [39] reported... 

Tensile properties Banana bunch> Nettle stalk, coir, celery fiber 27,39,52,53, 54,57,67... 

Tensile properties ISO 5079 1998 Textile fibers - Determination of breaking force and elongation at break of individual hbers Nettle stalk 38... 

Bacci et at [38] treated water retted nettle stalk fibers with Viscozyme and Pectinex Ultra SP-L enzymes. Viscozyme is a multienzymatic solution consisting of arabase, cellulase, b-glucanase, hemicellulase and xylase enzymes. Pectinex Ultra SP-L is an... 

L. Bacci, S. Di Lonardo, L. Albanese, G. Mastromei, and B. Perito, Effect of different extraction methods on fiber quality of nettle (Urtica dioica L.). Text. Res. J. 81, 827-837 (2011). L. Bacci, S. Baronti, S. Predieri, and N. di Virgilio, Fiber yield and quality of fiber nettle (Urtica dioicaL.) cultivated in Italy. Ind. Crops Prod. 29, 480-484 (2009). 

Bast (stem) fibers Flax, Hemp (and Sunhemp), Kenaf, Jute, Mesta, Ramie, Urena, Roselle, Papyrus, Cordia, Indian Malow, Nettle... 

---