Synthetic fibre carbon

Nylon A class of synthetic fibres and plastics, polyamides. Manufactured by condensation polymerization of ct, oj-aminomonocarboxylic acids or of aliphatic diamines with aliphatic dicarboxylic acids. Also rormed specifically, e.g. from caprolactam. The different Nylons are identified by reference to the carbon numbers of the diacid and diamine (e.g. Nylon 66 is from hexamethylene diamine and adipic acid). Thermoplastic materials with high m.p., insolubility, toughness, impact resistance, low friction. Used in monofilaments, textiles, cables, insulation and in packing materials. U.S. production 1983 11 megatonnes. 

When scouring synthetic fibres that are to be dyed with disperse dyes, nonionic scouring agents are best avoided unless they are formulated to have a high cloud point and are known not to adversely affect the dispersion properties of the dyes. Conversely, when scouring acrylic fibres, anionic surfactants should be avoided [156] because they are liable to interfere with the subsequent application of basic dyes. These fibres are usually scoured with an ethoxylated alcohol, either alone or with a mild alkali such as sodium carbonate or a phosphate. 

Adhesi ves Synthetic fibres Plasticizers Carbon black... 

Use a range of solvents for other polymer coatings, as detailed in Table 7.1. Tetrahydrofuran will dissolve and separate PVC and PVDC from nylon and polyester substrates in the cold. Carbon tetrachloride will dissolve and separate chlorinated polyethylene from nylon and polyester substrates. Toluene will dissolve and separate polyethylene from synthetic fibre substrates, apart from polyolefins, when the whole material should dissolve. 

Organic chemistry is the branch of chemistry in which covalent carbon compounds and their reactions are studied. A wide variety of classes of compounds such as vitamins, drugs, natural and synthetic fibres, as well as carbohydrates, peptides, and fats consist of organic molecules. Organic chemists determine the structures of organic molecules, study their various reactions, and develop procedures for the synthesis of organic substances. 

A wide range of physical properties can be achieved by varying the molecular weight of the epoxy component, the type of hardener and by adding catalysts and plasticizers. Epoxy polymers can be reinforced with glass, carbon and synthetic fibres prior to curing to increase strength and flexibility. 

Many synthetic fibres are available such as organic fibres based on petrochemicals. The most common of these are polyester, polyamide, acrylic and modacrylic, polypropylene, polyvinylalcohol, the segmented, high elastic polyurethanes (elastanes) and high performance fibres like glass, carbon, aramid, LCP, UHMWPE and PBO. 

Synthetic fibres take a static charge because they are non-conductive and only absorb small quantities of water. This effect is reinforced by low air humidity, particularly in winter, and soiling may be increased. Antistatic finishings reduce the high electrical resistance of fibres. These consist of hydrophilic surface active polar compounds (tensids), carbon particles, electrically guiding polymers or salts. Textiles may also be made antistatic by incorporating metallic or metallised fibres or conductive carbon fibres which are coated with polyamide. 

Commonly used natural fibres are cotton and silk, but also included are the regenerated cellulosic fibres (viscose rayon) these are widely used in non-implantable materials and healthcare/hygiene products. A wide variety of products and specific applications utilise the unique characteristics that synthetic fibres exhibit. Commonly used synthetic materials include polyester, polyamide, polytetrafluoroethylene (PTFE), polypropylene, carbon, glass, and so on. 

The pigmentation of synthetic fibres with carbon black has been practised for a good number of years. Latterly, its potential for promoting electrical conductivity in fibres has been explored. Nowadays, there is rapidly growing interest too within the textiles community in the incorporation of carbon nanotubes into fibres, particularly as a means of reinforcing them. However, their incorporation at a sufficient level would also render the fibres electrically conducting, and no doubt this property will be fully explored over the coming years. 

Natural fibres such as flax, hemp, silk, jute, sisal, kenaf, cotton, etc are being used to reinforce matrices mainly thermoplastics and thermosets by many researchers. The principal synthetic fibres in commercial use are various types of glass, carbon, or aramid although other fibres, such as boron, silicon carbide, and aluminium oxide, are used in limited quantities. All these fibres can be incorporated into a matrix either in continuous lengths or in discontinuous (short) lengths. Both these fibres have some advantages and disadvantages. 

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. 

Natural fibres can be derived either from plants (such as flax or hemp), produced by animals (such as silk or spider silk) or from minerals (such as asbestos). Table 6.1 shows the comparison of selected physical properties between natural fibres and synthetic fibres. Although the mechanical properties of natural fibres are very much lower than those of conventional synthetic fibres, such as glass or carbon fibres. 

Although natural fibres are highly comparable to conventional glass fibres on a per weight basis, the major drawback arises from the inherent variabUity of natural fibres [22]. Natural fibres can vary in terms of their dimensions and mechanical properties, even within the same cultivation. This situation is different from synthetic fibres, which can be manufactured uniformly (e.g., Toray s T700S carbon fibre has only a variability of 10% in its tensile strength and modulus [Commercial documentation - No AQ.866-9 (September 2003), Personal communication], 3% in its diameter). All natural fibres are hydrophilic in nature due to the presence... 

The process uses crystallizable polymers, of which the most important in PET. The first step is to injection mould (hence the name) a parison, or preform as it is more usually termed here. The preform is closed at the bottom and is considerably shorter and thicker than the final bottle. It is rapidly cooled (quenched) by using chilled water to cool the injection mould and this ensures that it is in its amorphous condition, i.e. no crystalline structure. Next it is reheated with infra-red elements to above its Tg, about 90-100 C for PET and enters the bottle mould and the mould is closed. The blow pin enters and pushes the soft preform downwards almost simultaneously the blow occurs, compressed air blowing the material outwards. The result is biaxial orientation - downwards from the movement of the blow pin, outwards from the action of the expanding air. The orientation induces crystallization, but in the form of lamellar crystals rather than spherulitic ones. This type of crystallization is strain-induced, and is characteristic of synthetic fibres and film, e.g. Melinex. It gives a transparent product with enhanced physical properties, both important for bottling carbonated drinks. The alternative name for the process is the stretch-blow process. Its main feature as a process is the control of the crystallinity of the polymer at its different stages. 

Polymers added in the form of fibres are now replacing the asbestos reinforced Portland cement that appeared in the mid-1980s. The fibres commonly used today besides steel and glass are PP and PA. A variety of other synthetic fibres can be used including PE, PES, aramid and carbon [39]. 

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