Contents
1 Measurement Technology in Textile Industry and Research . . . . . . 1
1.1 Measurement Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 SI and Other Unit Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Error Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Basic Principles of Measurements . . . . . . . . . . . . . . . . . . . . . . 10
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Conductive Yarns, Fabrics, and Coatings . . . . . . . . . . . . . . . . . . . . 13
2.1 Basics of Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2 Conductive Materials for Textile Applications . . . . . . . . . . . . . 17
2.3 Applications of Conductive Textiles . . . . . . . . . . . . . . . . . . . . 19
2.4 Measuring Conductive Properties of Yarns and Textiles . . . . . . 20
2.5 External Influences on Conductive Properties of Yarns and Textiles . . .. . . . . 25
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3 Magnetic Yarns, Fabrics, and Coatings . . . . . . . . . . . . . . . . . . . . . 31
3.1 Different Forms of Magnetism . . . . . . . . . . . . . . . . . . . . . . . . 31
3.2 Applications of Magnetic Textiles . . . . . . . . . . . . . . . . . . . . . . 35
3.3 Making Textiles Magnetic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.4 Measuring Textile Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.5 Simulation of Magnetism in Textiles . . . . . . . . . . . . . . . . . . . . 42
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4 Dielectric Yarns, Fabrics and Coatings . . . . . . . . . . . . . . . . . . . . . . 47
4.1 What Is Dielectricity? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.2 Applications of Dielectric Textiles and Coatings . . . . . . . . . . . 50
4.3 Measuring Dielectric Properties of Textiles and Coatings . . . . . 51
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
5 Optical Examinations of Fibers, Yarns, and Fabrics . . . . . . . . . . . . 55
5.1 Resolution and Magnification . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.2 Optical Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.3 Confocal Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
5.4 Scanning Electron Microscopy . . . . . . . . . . . . . . . . . . . . . . . . 69
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6 Diffractive Effects in Yarns and Fabrics . . . . . . . . . . . . . . . . . . . . . 75
6.1 How to Describe a Wave in a Quantitative Way? . . . . . . . . . . . 76
6.2 Diffraction at Simple Barriers . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.3 Diffraction in Multibarriers . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.4 Applications of Diffraction on Textile Fibers . . . . . . . . . . . . . . 79
6.5 Applications of Diffraction on Textile Fabrics . . . . . . . . . . . . . 85
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
7 Image Processing Techniques for Evaluation of Textile
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
7.1 The Cover Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
7.2 Surface Roughness of Textile Fabrics . . . . . . . . . . . . . . . . . . . 91
7.3 Definition and Common Measurement Methods of Yarn
Hairiness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
7.4 Determination of Yarn Hairiness Based on Microscopic Images
and Statistical Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
7.4.1 Information Stored in a Monochromatic Image . . . . . . . 93
7.4.2 Random Walk Method . . . . . . . . . . . . . . . . . . . . . . . . . 96
7.4.3 Practical Realization of Random Walk Experiments
at Optically Captured Maps . . . . . . . . . . . . . . . . . . . . . 99
7.4.4 Experiments with Basic Structures . . . . . . . . . . . . . . . . 102
7.4.5 Experiments with Two-Dimensional Textile
Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
7.4.6 Experiments with Hemp Fibers . . . . . . . . . . . . . . . . . . . 109
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
8 Thermal Properties of Textiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
8.1 Heat Transport Through Materials . . . . . . . . . . . . . . . . . . . . . . 113
8.2 Thermal Radiation of Bodies . . . . . . . . . . . . . . . . . . . . . . . . . . 117
8.3 Standardized Tests of Heat Transfer Through Textile
Fabrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
8.4 Other Measurements of Heat Transfer Through Textile
Fabrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
9 Hydrophobic and Hydrophilic Textiles . . . . . . . . . . . . . . . . . . . . . . 125
9.1 Hydrophobicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
9.2 Spray Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
9.3 Drop Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
9.4 Contact Angle Measurements . . . . . . . . . . . . . . . . . . . . . . . . . 129
9.5 Dynamic Measurements: Contact Angles and Roll-Off Angle . . . . 133
9.6 Comparison Between Different Hydrophobicity Measures . . . . . 135
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
10 Mechanical Properties of Yarns, Fabrics, and Coatings . . . . . . . . . 141
10.1 What Is the Reason for Elasticity? . . . . . . . . . . . . . . . . . . . . . . 141
10.2 Measuring Elastic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . 147
10.3 Measuring Adhesive Forces by a Universal Testing Machine . . . . 150
10.4 Bending Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
10.5 Drape and Drapability of Textile Fabrics . . . . . . . . . . . . . . . . . 153
10.6 Compressibility of Textile Materials . . . . . . . . . . . . . . . . . . . . 154
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
11 Stab and Cut Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
11.1 Stab- and Cut-Resistant Body Armor . . . . . . . . . . . . . . . . . . . . 159
11.2 Testing Stab and Cut Resistance . . . . . . . . . . . . . . . . . . . . . . . 160
11.3 Testing Gloves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
11.4 Testing Garments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Preface
Several books are available on the market dealing with well-known physical test methods which are typical for textile fibers, yarns, and fabrics, most of them necessitating expensive test equipment which is not always available to students and researchers.
This book communicates basic knowledge on the examination of textile materials, from fibers to yarns and knitted or woven fabrics, using mathematical and physical methods. Besides typical textile test procedures, defined by well-known standards, the book aims at showing new ways to examine textile materials and giving an overview of the possibilities as well as problems occurring when methods from other areas are transferred into the examination of textiles. The contents range from apparently simple measurements, such as resistance of conductive coatings on woven fabrics, to diffraction measurements on woven fabrics, to optical examination of knitted fabrics by mathematical approaches to study yarn hairiness and cover factor.
While some chapters focus on the easy realization of self-built, inexpensive lab equipment according to defined test standards, others provide new ideas to test textile materials with novel methods. The combination of textiles and mathematics, for example, cannot be found in a book yet; apparently mathematical methods have not yet been adopted in many cases from other areas into the examination of textiles.
Alternatively, measurements can be adopted from other scientific areas. In this case, the deviations of measurements on textiles from tests on rigid materials are described to avoid useless measurements and resulting interpretation errors. The measurements described here include (but are not limited to) optical examinations of fibers, yarns, and fabrics by different microscopic techniques; optical evaluation using a focused (laser) beam for diffraction images; image processing techniques for investigation of textile materials; tests of mechanical properties of textiles; thermal properties of fibers, yarns, fabrics, and coatings; special investigations of conductive or magnetic yarns; etc. We wish you an inspiring reading and a lot of success while testing your textiles, building your own test equipment, and developing existing methods further.