Fabric Mechanics (MSc PRESENTATION).pptx

Fabric Mechanics and fiber engineering

1. Durability, Strength and Degradation of Fabrics Submitted by: Suza Ahmed 2019-2-2-001 Dept. of Fabric Engg. Bangladesh University of Textiles Hasan Mahmud 2019-2-2-004 Mahmudur Rahman 2019-2-2-015 Submitted to: Dewan Murshed Ahmed Assistant Professor Dept. of Fabric Engineering Bangladesh University of Textiles

2. Contents Durability About Factors Test method and Standards Strength About Factors Test method and Standards Impact Degradation About Factors Test method and Standards

3. Durability Durability measures the ability of a textile material to endure and to maintain its essential and distinctive characteristics of strength, dimension, and appearance. The performance and characteristics of a textile are determined by its basic structural components, i.e. fiber, yarn, fabric structure, finishing treatments, and the interaction of these components with each other.

4. Wear on textile

5. Factors affecting durability Fabric construction Fibre and yarn properties Yarn structure Fabric strength Tensile strength Tearing strength Bursting strength Abrasion resistance Yarn slippage Seam strength Pile loss Dimensional stability Color fastness Sunlight exposure on textile Wrinkle resistance

6. Testing of Durability Tensile Strength : ‘Strip’ test’ and ‘Grab’ test Tear Strength : Elmendorf tearing test, ‘Tongue-tear’ test Bursting Strength: Ball burst test , Hydraulic burst test Abrasion resistance: Universal Wear Tester’ (Stoll), flexing and abrasion test, Martindale instrument Pilling : Pilling propensity, Martindale instrument, random tumble pilling test, cork-lined box Water repellency : Spray Test Water Resistance : Impact Penetration Test, Rain Test Skewness resulting from home laundering soil repellency test soil redeposition loss of finish during refurbishment Flame resistance Antimicrobial effectiveness

7. Fabric Strength One of the most important characteristics of woven fabric is strength. Strength is also measured in tensile, tearing or bursting strength. But, so many factors are related to the fabric strength like yarn count, twist, fibre fineness, stiffness, fibre density, fabric structure, cover, yarn density, no. of layer, tightness factor and so on.

8. Factors Affecting Strength Fibre Yarn Count, Spinning Systems, Yarn Bending Behavior Frictional Properties. Fabric Geometry Thread Density Weave Design Even testing condition like temperature, humidity, loading time, loading amount, between the jaws, testing methods also effects the variation the value of the fabric strength

9. Strength Test Methods Tensile strength: i)Strip Tensile Test (ASTM D5035)(Breaking force and elongation of textile fabrics) ii)Grab test (ASTM d5034) wiely used for heavy indstrial fabrics such as geotextile Tear strength: there are three types of tear strength test The tongue Trapezoid Elmendorf Bursting strength : Two types of brusting tst methods Hydraulic or Diaphragm burst Ball burst

10. Impact of Strength test Woven fabrics used as technical textiles are subjected to forces, which are parallel and perpendicular to fabric plane also. The effects of forces, which are parallel to fabric plane, and behaviors of fabric against these forces can be evaluated by measuring breaking strengths and elongation at breaks of fabrics along both warp and weft directions. On the other end, the effects of forces, which are perpendicular to fabric plane, and behaviors of fabric against these forces can be evaluated by bursting strength and impact tests. In selection of appropriate fabrics for appropriate garments, Filter fabrics ,geotextiles, parachutes, transportation bags,air and tension structure fabrics must often withstand considerable bursting pressure.For better burst rsistance,fabrics are designed to have equal properties in warp and filling direction. Some fabrics are designed to withstand impact loading. Ballistic protective fabrics, airbags and seat belts are example of these fabrics.

11. Fabric Degradation Textile materials deteriorate, during their useful life, by being subjected to the effects of many degradative mechanisms. Sunlight, weathering, laundering or dry-cleaning treatments, abrasion, perspiration, and other such unavoidable sources of fibre damage all exert their toll on physical or chemical properties to cause changes that can limit useful fabric life.

12. Factors Fibres degrade through many different routes; some of these are extremely slow such as gradual molecule breakdown while others are rapid such as physical tearing due to force.

13. Test Methods: Methodology to Characterize Textile degradation. Analytical Methodology/Instrumentation Finding and Materials Identified   Chemical Stain and solubility tests Identification of material, degree of degradation Viscosity Degree of polymerization Chromatography Thin layer Optical brighteners, finishes, stains and oils, etc. Liquid chromatography/mass spec Proteins Liquid chromatography/size exclusion chromatography Polymer chain fragments Mechanical Tensile testing Loss of strength Microscopy   Visual examination Type of damage, e.g. tearing, singed Low level microscopy Fibre damage, traces of substances High level microscopy (light, polarized and fluorescence, staining) Fibre and material identification Scanning electron microscopy (SEM) Morphology Analytical Methodology/Instrumentation Finding and Materials Identified   Spectroscopy Macro and micro FTIR/ATR Functional group changes X-ray diffraction Degree and orientation of the polymer Thermal analysis Melting point Identification Differential scanning calorimetry (DSC) Melting, decomposition and crystallisation range, glass transition temperature Thermogravimetric analysis (TGA) Determination of fibre components and damage Thermochemical analysis (TMA) Dimensional change Weighing Quantification of fibre loss

14. Standards: J.L.Mitchell and D.J.Carr studied Physical and mechanical degradation of shirting fabrics for laundering and in burial conditions. Laundering: In Their work two plain woven shirting fabrics were selected; (i) 100% cotton and (ii) 65% polyester and 35% cotton. Not- laundered, 6 times laundered and 60 times laundered specimens of each fabric were used; thus consideration of the age of the fabric was included in the experimental design. In Their study the use test standard 8A of BS EN ISO 6330/A1:2009 . The effect of laundering on fabrics was investigated using a JEOL 6700F field emission scanning electron microscope (FESEM). Burial conditions: Fabric specimens were buried in custom-made wooden boxes (four boxes of 800 mm x 600 mm x 500 mm dimensions). Two soil types were selected; 1002 clay and 100% sand. Specimens not buried and aged specimens that had been withdrawn were stored in ambient conditions Tear testing: Specimens were placed in standard environmental conditions of 20°C ± 2°C, 65% RH. ± 4% R.H. for 24. Testing was conducted using an Instron 5567 with a 1 kN load cell and a test speed of 100 mm/min. During testing, a graph of force vs. distance was generated using Bluehill 2 software. They use test standard BS EN ISO 13937:2000.

15. Conclusion The most influential variant on textile degradation is the actual fibre type ( Szostak-Kotowa , 2004). A variety of factors such as yarn thickness and linear density can also affect the rate of degradation as well as the addition of finishing treatments, which may accelerate or delay degradation. Therefore the degradation pathways of differing textiles will vary due to their differing chemical and physical structure, processes used during manufacture, end use and treatment.

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