Natural fibres sourcing

T. Nishino, Natural fibre sources, in Green Composites Polymer Composites and the Environment, C. Baillie, (Ed.), pp. 49, Woodhead Publishing, England (2004). 

High performance fibres are usually mixed or interwoven in the fabrics, or used as layered fabric structures so as to have a combination of multiple protection functions in protective clothing. Most of those high performance fibres, except those converted from natural fibre sources, are stiff and do not have moisture management properties, and some of them have poor durability therefore, the fabrics made from them are frequently used together... 

These laxatives act by softening and increasing faecal mass thus promoting normal peristalsis. The outer layers of cereal grains, especially wheat, form an important source of natural fibre in the diet and by increasing faecal mass natural fibre has laxative effects. 

Providing flame retardancy for fibre blends has proved to be a difficult task. Fibre blends, especially blends of natural fibres with synthetic fibres, usually exhibit a flammability that is worse than that of either component alone. Natural fibres develop a great deal of char during pyrolysis, whereas synthetic fibres often melt and drip when heated. This combination of thermal properties in a fabric made from a fibre blend results in a situation where the melted synthetic material is held in the contact with the heat source by the charred natural fibre. The natural fibre char acts as a candle wick for the molten synthetic material, allowing it to bum readily. This can be demonstrated by the LOl values of cotton (18-19), polyester (20-21) and a 50/50 blend of both (LOl 18), indicating ahigher flammability of the blend as described later (Section 8.11). But a rare case of the opposite behaviour is also known (modacrylic fibres with LOl 33 and cotton in blends from 40-60 % can raise the LOl to 35). 

Mechanical separation of cellulose fibrils from natural fibre resources may involve the process of grinding to apply shear stress to the longitudinal axis of the fibres, so that the fibrillated fibres will have diameters ranging 20—90 nm (Taniguchi and Okamura, 1998). Ultrasonic extraction is another approach to disrupt the adhesion among the fibrils so as to extract nanofibrils from both cellulosic and protein fibre sources... 

The starting point in the textile supply chain is the raw material preparation. Textile fibres are obtained from two main sources natural (cellulose or animal) fibres or synthetic fibres. Natural cellulosic fibres include conventional and organic cottons, rayon, linen, hemp, jute, ramie and sisal. Cotton is used to produce 40% of world textile products (Saicheua et al., 2012). The major environmental concern in cellulosic fibre production, especially for cotton fibre, is the chemical fertilizers and pesticides used during cultivation. The second concern is the high level of water consumption (Dave and Aspegren, 2010 Muthu, 2014). Cotton is one of the most popular natural fibres used in the world. Three percent of the world s cultivated land is used for cotton production and 16% of the world s insecticides are used on this crop alone (Saicheua et al., 2012 Muthu, 2014). Moreover, the use of chemical fertilizers, pesticides, machinery and electricity causes some human health and environmental problems. Also cotton growing requires 7—29 tonnes of water per kg of raw cotton fibres (KaUiala and Nousiainen, 1999). Other types of cellulosic fibres are hemp and flax, which can be considered to be the most significant sustainable fibres in the non cotton natural fibre sector (Werf, 2004 Muthu, 2014). 

Source From Biagiotti J., Puglia D. and Kenny Jose M. A Review on Natural Fibre-Based Composites—Part 1 Structure, Processing and Properties of Vegetable Fibres, J. Nat. Fibers, (1)2, 37-68, 2004. 

Natural fibres are raw materials directly obtainable from an animal, vegetable or mineral source for which the diameter is negligible in eomparison with the length. Along the centuries until comparatively reeently, natural fibres were the basis for producing clothes, paper, ships sails and insulation and building materials. 

Starch is the major carbohydrate reserve in higher plants. In contrast with cellulose that is present in dietary fibres, starch is digested by humans and represents one of the main sources of energy to sustain life. Bread, potato, rice and pasta are examples of the importance of starch in our society. Starch has also been extremely important for centuries in numerous non-food applications, for example, as glue for paper and wood [1] and as gum for the textile industry [2, 3]. Together with wood, natural fibres and leather, starch has been one of the choice materials since the inception of human technology. 

In order to use models to estimate composite properties, it is necessary to know the properties of the fibres, which vary widely depending on the source, age, separating techniques, moisture content, speed of testing, history of the fibre, etc. The properties of the individual fibres are therefore very difficult to measure. Moreover, in a natural fibre-polymer composite, the lignocellulosic phase is present in a wide range of diameters and lengths, some in the form of short filaments and others in forms that seem closer to the individual fibre. 

FRCs can be classified based on matrix and fibres. Based on fibre source, FRCs may be natural fibre reinforced and synthetic fibre reinforced. Based on fibre length, they can be continuous fibre reinforced and discontinuous fibre reinforced. But FRCs are generally classified based on matrix component. Thus according to the types of matrices stated earlier, composites are of three types (i) ceramic matrix composites (CMCs), (ii) metal matrix composites (MMCs) and (iii) organic matrix composites (OMCs). Organic matrix is subdivided into two classes, namely polymer matrix and carbon matrix. A short description of all these types of composites are discussed below. 

The two main sources of natural fibres are plants and animals. The main component of animal based fibres is various proteins examples include mohair, wool, silk, alpaca, angora, etc. The components of plant fibres are cellulose microfibrils dispersed in an amorphous matrix of lignin and hemi-cellulose examples include cotton, jute, flax, ramie, sisal, hemp, etc. 

Abstract This chapter deals with the structure, properties and applications of natural fibres. Extraction methods of Natural Fibres from different sources have been discussed in detail. Natural fibres have the special advantage of high specific strength and sustainability, which make them ideal candidates for reinforcement in various polymeric matrices. Natural fibres find application in various fields like construction, automobile industry and also in soil conservation. It is the main source of cellulose, an eminent representative of nanomaterial. Extractions of cellulose from plant-based fibres are discussed in detail. Various mediods used for characterization of cellulose nanofibres and advantages of these nanofibres have also been dealt with. 

Natural fibre derived from animal sources (silkworm)... 

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