Abrasion Resistance of High Performance Fabrics
Abrasion resistance is the ability of a fabric to resist surface wear caused by flat rubbing contact with another material.
Introduction The second half of the 20th century was marked by the widespread use of textile materials in a variety of non-textile areas - from the application of fibre composites, high structural materials, a variety of materials and products used in industry, vehicles (cars, boats, planes, spaceships), professional sports, agriculture, road building and construction, protection of people and animals, environment protection, to medicine. Such textile materials are referred to as Technical Textiles, and are manufactured mostly of the fibres with some specific properties, such as high-tech fibres that under the environmental conditions retain their physical characteristics for a longer time, characterized by their high quality. These new generations of high-quality textile materials, manufactured employing most advanced technological processes, offered the road to making fabrics characterized by enhanced physical and mechanical properties and resistance to different impacts in use, while at the same time retaining their textile properties, such as colour fastness, dimensional stability, strength, good resistance to abrasion, etc. These materials, in the form of clothing, textile cartridges for shoes or any other end-use product, offer the retention of good looks, and thus extended usage. However, when it comes to satisfying the needs of soldiers, policemen, mountaineers and many other specific users, whose life depends on good abrasion resistance of textile materials they use, high performance acquires completely different meaning. High performance materials are no longer a mystery; it is just a matter of time when the next generation of better and smarter fabrics will appear. As in everyday life, people like to be surrounded with textile materials that retain their original properties for a long time, together with high wear resistance under the conditions of use, i.e. high resistance to abrasion. It is necessary to choose the best method and appropriate procedures to test them, as well as the manners of expressing test results. This may be a good starting point for the development of new methods and test procedures, as well as an impulse for the construction of appropriate measurement equipment. Today, there are several different types of apparatuses for testing abrasion resistance. They have evolved over time to include different kinds of loading conditions and materials, in order to be truer and closer to real conditions. Their results are not mutually www.qinsun.com 36 Abrasion Resistance of Materials comparable and often opposing results have been reported using different instruments. Lately, resistance to wear has been most common tested by Martindale, while the processes of circular wear with the tangential direction by Schopper have been mostly abandoned. However, testing abrasion resistance by Schopper has its advantages and disadvantages. The use of SiC paper provides intensive wear at lower number of cycles and tangential contact sample with the abrading material. When using the Martindale method, the sample moves according to the Lissajous figure, standard wool fabric being abraded over the entire surface and this certainly contributes to getting reliable results. This method is ideal for everyday fabrics, but when it comes to the fabrics in the high performance fabrics group, the method can be modified, which we discussed before [Somogyi et al. 2008]. Why is this important? It is well known that a textile material with high resistance to abrasion, such as Cordura®, can stand 100 thousand rubs by Martindale without a mass loss or specimen breakdown. Obviously, this kind of material will abrade a woven wool fabric, and not the other way around. Thus, the question arises whether the determination of Cordura® abrasion resistance, or some other the similar high performance fabric, using the Martindale methods, is suitable or the methods should be modified in order to obtain significant results? In addition to the modification of Martindale in the manner described before [Somogyi et al. 2008], some modifications of standard methods of testing abrasion resistance by Martindale are also possible, all of them aiming at obtaining significant results. The Department of Materials, Fibres and Textile Testing, the Faculty of Textile Technology, University of Zagreb, has been involved in testing high quality fabrics intended for military and police use for some time. A number of high performance fabrics have been investigated and the need to determine wet abrasion resistance showed to be one of the key requirements throughout the investigation. Fabrics intended for military and police uniforms are exposed to a number of physical and chemical agents in the course of regular use, rain and moisture being most frequently encountered. This means that, apart from testing dry abrasion resistance, as required by current standard, standard should be complemented by including testing wet abrasion. Such a method for determining abrasion resistance is particularly suitable for damage detection, as damaged textile materials show more pronounced reduction in strength in wet state. The advantage of the modification is that the testing proposed can be done using the same methods, procedures and equipment as with dry materials. Similar to the above, permeability of air and resistance to water with good resistance to abrasion are very important for high performance fabrics used by mountain climbers, soldiers, policemen, firemen, etc. The Martindale method can again be ideally modified to suit the purpose; using the same apparatus, procedure and slightly modified methods it offers proper insight into the influence of wear on water or air permeability. Additional knowledge on the impact of testing abrasion resistance, as related to air permeability and water resistance, will be acquired in this way as well.
