Fibres friction

Water soluble fibre processing aid which imparts low fibre to metal and medium to high fibre to fibre friction together with good antistatic properties. DRAFCOL S6H is recommended for use on man-made fibres and their blends on a wide variety of processing systems. 

Alternatively, non-woven fabrics are produced by directly transforming fibres after carding (formation of the web) into a fabric, without the intermediation of the yarn. Except in the production of felts, which makes use of the felting property of wool (and other animal fibres), fibre-fibre friction plays no role here and there are resins used for bonding. 

Additional surface treatments, using graphite as a base, are also applied where the dust stream may contain incandescent particles leading to pinholes (often found in the asphalt industry) or a mixture of silicone and graphite, as in the case of glass filter media, to reduce fibre-fibre friction. Still further treatments have been developed to counter specific problems arising from dusts such as those found in the ferrous or alumina industries. 

Compression Test Results. Fig. 1 shows the compression cycle curves obtained with the 2 multilayer structures (NWS). The results for the three samples tested in each case are all presented. The behaviour is roughly the same for both structures. A plateau is visible at the beginning of the test, attributed to a small misalignment of the compression plates. This kind of curves is typical for nonwovens [7], owing to the architecture of fibres inside the material. The fibres are not fixed by resin, so the fibres are able to slide over each other during the compression test, and the load corresponds to the inter-fibre friction and to fibre bending. 

Porous 3D composites have been developed from para-aramid nonwoven sandwiches composed of different monolayer structures. The dry and resin-impregnated materials have been characterized in terms of density, porosity and air permeability. In an attempt to understand the fibre arrangements inside the material, the theoretical pore size and distance between fibre contacts have been evaluated. The compression results obtained with the composites can be related to this fibre arrangement which defines more specifically the number of fibre contacts and/or interfacings. This parameter is however not relevant for the compressive behaviour of the dry nonwovens, which depends largely on the fibre bending modulus and inter-fibre frictions. 

Figure 2. Schematic diagram of the hanging fibre friction apparatus. Details are given in the text.

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. 

Friction pendulum test Steel shoe explodes fibre shoe unaffected (Ref 13)... 

Should have no adverse effects on frictional characteristics of wool fibres or yarns. 

To enhance mechanical properties and decrease wear, glass fibres are added to polymers but they are abrasive and attack the opposing surface. According to the circumstances they can also increase the coefficient of friction. 

Carbon fibres are more satisfactory, simultaneously bringing a lower friction coefficient and lower wear. 

Table 3.18 shows the effects of several lubricating fillers on the friction properties of polyamides 6 or 66 possibly reinforced with glass or carbon fibres. 

Some self-lubricating grades of polycarbonate are marketed, containing specific additives and reinforced with glass or carbon fibres. The coefficients of friction are in a good range, from 0.1 up to 0.21. Wear resistance is not as good as for PA 66. 

Neat and glass fibre reinforced grades can be used for tribological applications with rather high coefficients of friction in a range from 0.3 up to 0.5. 

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