Natural fibres cotton

Many shapes are to be found in natural fibres. Cotton fibres are C-shaped and have a hole in the centre. Flax and hemp are relatively smooth. Wool fibres are more or less round but have a scaled surface and may be used for felting, a process in which the scales are made to adhere to each other by mechanical forces, assisted by the application of a surface solvent chemical. 

Huber, T. and Mussig, J. (2008). Fibre matrix adhesion of natural fibres cotton, flax and hemp in polymeric matrices analyzed with the single fibre fi agmentation test. Composite Interfaces 15(2-3), 335-349. 

These materials are available with fillers of wood flour, paper, glass, natural fibres, cotton, nylon and in many grades and colours, thus ensuring that design is not restricted by availability of materials. 

Hyde, K., Rusa, M. and Hinestroza, J., Layer-by-layer deposition of polyelectrolyte nanolayers on natural fibres cotton. Nanotechnology 2005. 16 S422-S428. 

Man-made fibres produced as continuous filaments and then cut into short lengths to match those of some natural fibres such as cotton or wool. The staple of cotton, wool, staple fibre, etc., is an indication of the average fibre length. Stark Rubber... 

In the last 30 to 40 years plastics have taken over as replacement materials for metals, glass, paper and wood as well as for natural fibres such as cotton and wool. 

By far the most produced fibre in the world is cotton. Its production is almost 30 times that of jute (Figure 5.11). The extended industrial textile applications of cotton account for such huge production. Nevertheless, it is the other fibres that occupy an important place in biomaterials production. We should also note that most of the natural fibres (except wood) come from emerging countries, especially from Asia. 

Trace metals can be leached out of some natural fibres. To determine copper in webbing, rope and cotton duck, Simonian [184] warmed, to near boiling, 2—3 g fabric with 80—90 ml of 0.5 M hydrochloric acid. The sample was filtered and made up to 200 ml before aspiration into an air/acetylene flame. 

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). 

CONDENSOL II is recommended for synthetics and blends of synthetic and natural fibres, e.g. polyester/cotton or polyester/ wool. 

There are three types of regenerated natural fibres - rayon, acetate and protein -the first two are derived from cotton linters or pine wood. Wool like protein based artificial fibres may be regenerated from animal and vegetable proteins. 

Although jute is a natural fibre like cotton, it differs in chemical composition. Unlike cotton jute contains a high percentage of non-cellulosic matter (about 40%) and the pre-treatment processes of jute are somewhat different from that of cotton. Scouring of jute with caustic soda under pressure cannot be carried out like cotton because of removal of hemi-cellulose which results in high losses of tensile strength (10-15%) and weight (6-8%). 

PL A fabrics exhibit the comfort and touch of natural fibres such as cotton, silk and wool while having the performance, cost, and easy care characteristics of synthetics. PLA fibres demonstrate excellent resiliency, outstanding crimp retention and improved wicking compared with natural fibres. Fabrics produced from PLA are being utilized for their silky feel, drape, durability and water vapour permeability used to create breathability suitable for sport clothing applications [195]. 

Textiles for apparel are commonly woven or knitted from natural or manufactured hbres. Natural hbres include ceUulosic fibres such as cotton, hnen and hemp, or protein hbres such as silk and wool. Growing of natural fibres frequently involves significant water, land and chemical use. Natural fibres are biodegradable, however, because of the chemicals used in the finishing and dyeing processes, these fibres can still negatively impact soil and groundwater upon disposal. 

Synthetic fibres, followed by cotton, are the most common in apparel production. Although cotton consumption has risen steadily in the past two decades, synthetic consumption has grown much faster and now dominates global fibre production. Cotton accounts for 32.9% of global textile production, synthetic fibres including polyester, acrylic, nylon (polyamide) and polypropylene for 60.1%, wool 2.1%, flax (linen) 1.0% and other ceUulosic 3.9% (Shui and Plastina, 2013). In the apparel context, manufactured fibres can be engineered to mimic natural fibres in handle, function and aesthetic, which makes them attractive for both apparel manufacturers and end consumers. 

This process is used to recycle fabrics made from natural fibres such as cotton and wool as well as synthetic fibres including polyesters, nylons and blended fibres. Hawley (2006) describes the mechanical processing technique used in facilities in Prato, Italy, where acrylic textiles are shredded down to fibre. In hw example, acrylic garments were sorted and cut up, mechanically shredded to fibre, and then re-spun into acrylic yam for weaving into blanketing (Hawley, 2006). 

International Cotton Advisory Committee, 2013. Overview of world fiber production. In Paper Presaited at the 1st International Conference on Natural Fibres Guimaraes, Portugal, June 9—11, 2013. http //dnfi.org/wp-content/uploads/2013/08/Portugal-Paper.pdf (accessed 29.11.14.). 

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). 

DoreTex is a yam-spinning company that focuses on high-end yams. While 60% of the company s output is synthetic, the company s core focus is cotton. This is both because the DoreTex production technology is based on the system used for cotton and because the natural fibre, along with linen, hemp, silk, wool and cashmere, is what ensmes the company s privileged relationship with the fashion industry. Consequently, the application of the decision-making process was focussed on the cotton division. 

Most of the techniques employed in fibre analysis are nondestructive tests to determine whether the fibre is natural (obtained from animal, plant, or mineral) or synthetic (wholly manufactured from chemicals or regenerated from natural fibres) and the fibre type (e.g., determining if the fibre is wool, cotton, nylon, polyester, etc.). Whether any chemical treatments have been carried out (such as bleaching or the use of delustrants) is noted and the colour is also determined. Many of the techniques commonly used in these analyses include low- and high-power microscopes, Fourier transform infrared (FTIR) microscopy, polarising Ught microscopy, fluorescence microscopy, and microspectrophotometry (MSP). 

Wool and cotton fibres are still iding applications in leisure wear. S5 thetic fibres can either be modified during manufacture, for example, by producing hollow fibres and fibres with irregular cross-section, or be optimally blended with natural fibres to improve their thermophysiological and sensory properties. Synthetic fibres with improved ultraviolet (UV) resistance and having antimicrobial properties are also commercially available for use in sportswear. 

The designers during the early nineteenth century were limited to the fibres, yams and fabrics of that period. These were all natural fibres, which included cotton, flax and protein fibres such as wool and silk. By the middle of the century, other fibres were making their mark on the scene—synthetic fibres were created, such as polyamide, known by its commercial name of nylon. This was followed by polyester and many other synthetic materials, including acetates and spandex fibres, which we know today as Lycra (Figure 6.1). 

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