Understanding and improving the durability of textiles

P ETRULIS , Kaunas University of Technology, Lithuania 1.3 Fibre and yarn properties that affect fabric durability 91.4 Durability of woven, knitted and nonwoven fabric structures 141.5

The Textile Institute is a unique organisation in textiles, clothing and footwear.Incorporated in England by a Royal Charter granted in 1925, the Institute hasindividual and corporate members in over 90 countries The aim of the Institute is

to facilitate learning, recognise achievement, reward excellence and disseminateinformation within the global textiles, clothing and footwear industries

Historically, The Textile Institute has published books of interest to its membersand the textile industry To maintain this policy, the Institute has entered intopartnership with Woodhead Publishing Limited to ensure that Institute membersand the textile industry continue to have access to high calibre titles on textilescience and technology

Most Woodhead titles on textiles are now published in collaboration with TheTextile Institute Through this arrangement, the Institute provides an EditorialBoard which advises Woodhead on appropriate titles for future publication andsuggests possible editors and authors for these books Each book published underthis arrangement carries the Institute’s logo

Woodhead books published in collaboration with The Textile Institute areoffered to Textile Institute members at a substantial discount These books,together with those published by The Textile Institute that are still in print, areoffered on the Woodhead website at: www.woodheadpublishing.com TextileInstitute books still in print are also available directly from the Institute’s websiteat: www.textileinstitutebooks.com

A list of Woodhead books on textile science and technology, most of which havebeen published in collaboration with The Textile Institute, can be found towardsthe end of the contents pages

Understanding and improving the durability

of textiles

Edited by Patricia A Annis

Woodhead Publishing Limited, 80 High Street, Sawston, Cambridge CB22 3HJ, UK

First published 2012, Woodhead Publishing Limited

© Woodhead Publishing Limited, 2012 Note: the publisher has made every effort to ensure that permission for copyright material has been obtained by authors wishing to use such material The authors and the publisher will be glad to hear from any copyright holder it has not been possible to contact.

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ISSN 2042-0803 Woodhead Publishing Series in Textiles (print)

ISSN 2042-0811 Woodhead Publishing Series in Textiles (online)

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Contributor contact details xi Woodhead Publishing Series in Textiles xiii

Part I Aspects of textile durability

type on textile durability: woven, knitted

D P ETRULIS , Kaunas University of Technology, Lithuania

1.3 Fibre and yarn properties that affect fabric durability 91.4 Durability of woven, knitted and nonwoven fabric structures 141.5 Durability of technical textiles: medical and breathable

J N C HAKRABORTY , National Institute of Technology, India

2.2 Principles of fabric strength and its influence on durability 34

2.4 Factors affecting fabric strength 45

3 Dimensional stability of fabrics: resistance to

S F N G , C L H UI and C I P , The Hong Kong Polytechnic

and wrinkle resistance of cotton and other fabrics 70

W X U and X W ANG , Wuhan Textile University, China

4.3 Properties affected by durable press treatments and other

J V ALLDEPERAS -M ORELL and F C ARRILLO -N AVARRETE , Universitat

Politècnica de Catalunya, Spain

6 Effects of light exposure on textile durability 104

V R UBEZIENE , S V ARNAITE , J B ALTUSNIKAITE and I P ADLECKIENE , SRI Center for Physical Sciences and Technology Textile Institute,

Lithuania

6.3 The influence of sunlight on synthetic and high

M B IDE , University of Rhode Island, USA

7.6 Testing the effects of laundering on fabric properties 137

Part II Durability of particular types of textiles

8 Durable antimicrobial textiles: types, finishes

V P D HENDE , I R H ARDIN and J L OCKLIN , University of Georgia,

USA

8.5 Applications of antimicrobial finishes: the example of

A S HAW , University of Maryland Eastern Shore, USA

9.3 Other factors that can affect the durability of protective

P G ARSIDE , British Library, UK

10.2 Main durability issues that affect historic textiles 185

10.4 Physical context, environment and storage conditions 192

N L UXFORD , University College London, UK

11.5 The impact of treatments to improve the durability of silk 219

12 Durable geotextiles 233

H.-Y J EON , Inha University, Republic of Korea

12.2 Durability of nonwoven geotextiles in chemical

12.3 Protection performance of nonwoven geotextiles in waste

Prof Donatas Petrulis

Department of Textile Technology

Kaunas University of Technology

Department of Textile Technology

National Institute of Technology

C IpInstitute of Textiles and ClothingThe Hong Kong Polytechnic UniversityHung Hom, Kowloon

Hong KongEmail: tcngsf@polyu.edu.hkChapter 4

Prof Weilin Xu* and A Prof XinWang

School of Textile Science andEngineering

Wuhan Textile UniversityWuhan 430200

ChinaEmail: weilin-xu@hotmail.com;wangxin0222@hotmail.comChapter 5

Prof José Valldeperas-Morell* andProf Fernando Carrillo-NavarreteINTEXTER

Universitat Politècnica de CatalunyaColom 15

Terrassa 08222Spain

Email: valldeperas@intexter.upc.edu;fernando.carrillo@upc.edu

Chapter 6

Dr Vitalija Rubeziene*, Dr Sandra

Varnaite, Dr Julija Baltusnikaite and

Dr Ingrida Padleckiene

SRI Center for Physical Sciences and

Technology Textile Institute

Department of Textiles, Fashion

Mer-chandising and Design

University of Rhode Island

Department of Textiles,

Merchandis-ing & Interiors

MD 21853USAEmail: ashaw@umes.eduChapter 10

Paul GarsideBritish Library

96 Euston RoadLondon NW1 2DBUK

Email: paul.garside@bl.ukChapter 11

Dr Naomi LuxfordPost-doctoral Research FellowCentre for Sustainable HeritageBartlett School of Graduate StudiesUniversity College LondonCentral House

14 Upper Woburn PlaceLondon WC1H 0NNUK

Email: n.luxford@ucl.ac.ukChapter 12

Prof H.-Y JeonDivision of Nano-systems EngineeringInha University

253 Yonghyun-dong, Nam-guIncheon, 402-751

Republic of KoreaEmail: hyjeon@inha.ac.kr

1 Watson’s textile design and colour Seventh edition

Edited by Z Grosicki

2 Watson’s advanced textile design

Edited by Z Grosicki

3 Weaving Second edition

P R Lord and M H Mohamed

4 Handbook of textile fibres Volume 1: Natural fibres

7 New fibers Second edition

T Hongu and G O Phillips

8 Atlas of fibre fracture and damage to textiles Second edition

J W S Hearle, B Lomas and W D Cooke

12 Handbook of technical textiles

Edited by A R Horrocks and S C Anand

13 Textiles in automotive engineering

W Fung and J M Hardcastle

14 Handbook of textile design

J Wilson

15 High-performance fibres

Edited by J W S Hearle

16 Knitting technology Third edition

21 Yarn texturing technology

J W S Hearle, L Hollick and D K Wilson

22 Encyclopedia of textile finishing

H-K Rouette

23 Coated and laminated textiles

W Fung

24 Fancy yarns

R H Gong and R M Wright

25 Wool: Science and technology

Edited by W S Simpson and G Crawshaw

26 Dictionary of textile finishing

29 Textile processing with enzymes

Edited by A Cavaco-Paulo and G Gübitz

30 The China and Hong Kong denim industry

Y Li, L Yao and K W Yeung

31 The World Trade Organization and international denim trading

Y Li, Y Shen, L Yao and E Newton

32 Chemical finishing of textiles

W D Schindler and P J Hauser

33 Clothing appearance and fit

J Fan, W Yu and L Hunter

34 Handbook of fibre rope technology

H A McKenna, J W S Hearle and N O’Hear

35 Structure and mechanics of woven fabrics

J Hu

36 Synthetic fibres: nylon, polyester, acrylic, polyolefin

Edited by J E McIntyre

37 Woollen and worsted woven fabric design

E G Gilligan

38 Analytical electrochemistry in textiles

P Westbroek, G Priniotakis and P Kiekens

39 Bast and other plant fibres

43 New millennium fibers

T Hongu, M Takigami and G O Phillips

44 Textiles for protection

48 Medical textiles and biomaterials for healthcare

Edited by S C Anand, M Miraftab, S Rajendran and J F Kennedy

49 Total colour management in textiles

52 Biomechanical engineering of textiles and clothing

Edited by Y Li and D X-Q Dai

53 Digital printing of textiles

Edited by H Ujiie

54 Intelligent textiles and clothing

Edited by H R Mattila

55 Innovation and technology of women’s intimate apparel

W Yu, J Fan, S C Harlock and S P Ng

56 Thermal and moisture transport in fibrous materials

Edited by N Pan and P Gibson

57 Geosynthetics in civil engineering

Edited by R W Sarsby

58 Handbook of nonwovens

Edited by S Russell

59 Cotton: Science and technology

Edited by S Gordon and Y-L Hsieh

60 Ecotextiles

Edited by M Miraftab and A R Horrocks

61 Composite forming technologies

Edited by A C Long

62 Plasma technology for textiles

Edited by R Shishoo

63 Smart textiles for medicine and healthcare

Edited by L Van Langenhove

67 Nanofibers and nanotechnology in textiles

Edited by P Brown and K Stevens

68 Physical properties of textile fibres Fourth edition

W E Morton and J W S Hearle

69 Advances in apparel production

Edited by C Fairhurst

70 Advances in fire retardant materials

Edited by A R Horrocks and D Price

71 Polyesters and polyamides

Edited by B L Deopura, R Alagirusamy, M Joshi and B S Gupta

72 Advances in wool technology

Edited by N A G Johnson and I Russell

75 Medical and healthcare textiles

Edited by S C Anand, J F Kennedy, M Miraftab and S Rajendran

76 Fabric testing

Edited by J Hu

77 Biologically inspired textiles

Edited by A Abbott and M Ellison

78 Friction in textile materials

Edited by B S Gupta

79 Textile advances in the automotive industry

83 Smart clothes and wearable technology

Edited by J McCann and D Bryson

84 Identification of textile fibres

88 Handbook of textile fibre structure Volume 1 and Volume 2

Edited by S J Eichhorn, J W S Hearle, M Jaffe and T Kikutani

89 Advances in knitting technology

96 Engineering apparel fabrics and garments

J Fan and L Hunter

97 Surface modification of textiles

100 Handbook of medical textiles

Edited by V T Bartels

101 Technical textile yarns

Edited by R Alagirusamy and A Das

102 Applications of nonwovens in technical textiles

107 Advances in textile biotechnology

Edited by V A Nierstrasz and A Cavaco-Paulo

108 Textiles for hygiene and infection control

Edited by B McCarthy

109 Nanofunctional textiles

Edited by Y Li

110 Joining textiles: Principles and applications

Edited by I Jones and G Stylios

111 Soft computing in textile engineering

Edited by A Majumdar

112 Textile design

Edited by A Briggs-Goode and K Townsend

113 Biotextiles as medical implants

Edited by M King and B Gupta

114 Textile thermal bioengineering

Edited by Y Li

115 Woven textile structure

B K Behera and P K Hari

116 Handbook of textile and industrial dyeing Volume 1: Principles, processes and types of dyes

119 Handbook of natural fibres Volume 2: Processing and applications

Edited by R Kozlowski

120 Functional textiles for improved performance, protection and health

Edited by N Pan and G Sun

121 Computer technology for textiles and apparel

130 Modelling, simulation and control of the dyeing process

R Shamey and X Zhao

131 Process control in textile manufacturing

Edited by A Majumdar, A Das, R Alagirusamy and V K Kothari

132 Understanding and improving the durability of textiles

139 Multidisciplinary know-how for smart textile development

142 Textile-led design for the active ageing population

J McCann and D Bryson

143 Optimizing decision making in clothing management using artificial intelligence (AI): From production to fashion retail

W K Wong, Z X Guo and S Y S Leung

144 Mechanisms of flat weaving technology

V Choogin, P Bandara and E Chepelyuk

145 Innovative jacquard textile design using digital technologies

148 Anthropometry, apparel sizing and design

D Gupta and N Zakaria

P A A N N I S, University of Georgia, USA

Textile durability is the measure of the ability of a textile to endure and to maintainits essential and distinctive characteristics of strength, dimension, and appearance.Durability is determined by the length of time that a textile can maintain its innatecharacteristics in use This time will vary depending on characteristics of thetextile in question, the amount and degree of use, and the environment.1

The characteristics and performance of a textile are determined by its basicstructural components, i.e fiber, yarn, fabric structure, finishing treatments, andthe interaction of these components with each other Failure of one or more ofthese components will adversely affect the durability of a textile material Theamount and degree of use are determined by the type of textile in question and varywidely depending upon the individual user and application of the textile material.Exposure to the environment can be as simple as use in the indoor environmentaccompanied by refurbishing and care to as complex as burial in the ground Auser’s expectations for serviceability also influence judgment about the durability

of a textile Finally, the scope of durability of textile materials should not be limited

to physical integrity but also should encompasses a textile’s resistance to changes

in dimension, appearance and color

Thus, understanding and improving textile durability is a complex endeavor.The approach taken in this book is to discuss the durability of textile materials intwo parts In Part I, the many aspects of textile science that contribute to textiledurability are discussed Part II is devoted to case studies of the durability ofparticular types of textiles Test methods used to evaluate specific aspects oftextile durability and recent developments and future trends are part of eachchapter in both sections of the book

The effects of the interaction of fabric construction, yarn structure, and fibercharacteristics on textile durability are addressed in detail in Chapter 1 Thisdiscussion includes woven, knit, and nonwoven fabrics, as well as advancedconstructions and textile composites Strength and abrasion resistance are oftenconsidered to be synonymous with textile durability Thus, enhancing the strengthproperties of a textile by judicious selection and manipulation of its structuralcomponents are the focus of Chapter 2 Chapter 3 addresses durability in terms ofdimensional stability Understanding how the components of a textile interact toinfluence its dimensional stability, as well as approaches to maintaining thedimensions of fabrics during processing, use, and care are the focus of Chapter 3

Improving appearance retention through durable press treatments is the topic ofChapter 4 Although improvement of smoothness is a desirable attribute, durablepress treatments may adversely affect the physical durability of fabrics Thus, themechanisms and technology of durable press finishing are described in the context

of maintaining the physical integrity of treated fabrics The many and variedaspects of the colorfastness of textiles are described in Chapter 5 Color instabilityhas implications for the discussion of textile durability Poor durability of colorcharacteristics may result in a textile being discarded long before it is physically

‘worn out’ Resistance to degradation by ultraviolet (UV) radiation is an importantcharacteristic of many types of outdoor textiles and is a critical requirement forsome protective fabrics Chapter 6 discusses the detrimental effects of light ontextiles and how resistance to photo degradation can be improved Chapter 7concludes Part I of the book with an overview of the many types of test methodsused to measure and predict the durability of textile materials

The durability of particular types of textiles is given extensive treatment in Part

II of this book Chapter 8 discusses how the durability of textiles can be improvedusing antimicrobial agents Durable antimicrobial agents are used to protect theuser of a textile or the textile itself from biodegradation by microorganisms.Chapter 9 draws attention to changes in durability of textiles during use and carethat may affect the performance of clothing with a variety of protective functions.Performance assessments based on laboratory tests of preconditioned new gar-ments may not be comparable to the wear and tear that garments undergo duringactual use Factors that influence the durability of historic textiles are discussed inChapter 10 Not unlike contemporary textiles, interaction of the textile structuralcharacteristics – i.e fiber, yarn, and fabric – influence durability as well as otherconsiderations specific to historic textiles such as physical context, environmentalfactors, storage conditions, and conservation practices Chapter 11 outlines thedeterioration processes that limit the durability of historic silk and current treat-ments used to improve the durability of modern silk The long-term effects ofpreventive conservation on the durability of silk also are discussed using a historichouse case study Geotextiles (textiles used on or in the ground) have a widevariety of functional applications; Chapter 12 describes assessment of the physicaland chemical properties that influence the durability of woven and nonwovengeotextiles used in landfill and ground stabilization applications

As editor of this book, I would like to thank the various individual chaptercontributors and the staff of Woodhead Publishing Limited for making this bookpossible The information presented should contribute significantly to the litera-ture on understanding and improving the durability of textile materials

Reference

1 ASTM International Online Dictionary of Engineering Science and Technology (2012)

http://www.astm.org/TERMINOLOGY/

The influence of fabric construction and fibre type on textile durability: woven, knitted

and nonwoven fabrics

D P E T R U L I S, Kaunas University of Technology, Lithuania

Abstract: This chapter discusses fabric construction and its effect on fabric

durability The chapter first reviews the importance of understanding fabric construction It then describes types of textile structures and construction indices The properties of fibres and yarns and fabric construction indices that affect fabric durability are given Basic data and the most recent information

on the durability of woven fabrics, knitted fabrics and nonwovens are provided At the end of this chapter, the durability of advanced examples of textile structures and the future trends of durable textile structures are discussed.

Key words: fabric construction, fabric durability, knitted fabrics,

nonwovens, woven fabrics.

The construction of materials is a significant factor in their initial properties whichinfluences the functionality of materials during their use ‘Construction’ is ageneral term used in textiles that refers to fibre, yarn and fabric dimensions, andalso to the manner in which the elements of the textile material are arranged in itsstructure

Constructions of textile materials are seldom designed to withstand a singlestress application of high magnitude Fabrics are subjected to long usage and,during their lifetime, will experience a series of repeated stress applications andremovals Tensioning, buckling, flexing, and abrasion are examples of suchrepeated stress applications Unidirectional, bidirectional or multi-directionalinfluences will occur during wear It is therefore essential that the design of textilestructures takes into account the nature of the damage and construction changes towhich the materials will be subjected in actual use

Engineered fabric manufacturing requires a thorough understanding of ity properties and their key control construction parameters The wear life offabrics is complex, not only because of the many different factors of fabricconstruction over a variety of structural levels, but also because the relativeimportance of each will differ greatly according to the conditions of wear

durabil-As far as is known, the first significant studies in this field (Hamburger, 1945;Morton, 1948; Backer, 1951; and others) were made in the middle of the 20thcentury For instance, in 1945 Hamburger studied the mechanics of abrasion intextile materials In this study, two essentially different classes of factors govern-ing abrasion resistance in textile structures were noted: the inherent abrasionresistance of the material and the geometry of the composite structure The lattermay be characterised as the ‘form factor’ The effect of the geometric form factor

is more pronounced in structures such as woven, knitted and other fabrics madefrom yarns than it is in sheets, films and extruded items It should be noted that theface and the back of certain woven fabrics resist abrasion quite differently because

of the geometric form factors

Through the use of various combinations of diameter, spacing and the manner

in which yarns are interlaced, numerous factors may be introduced to ensure thatthe fabric does not behave in the same manner as the homogeneous material ofwhich it is chemically constituted The literature shows that fabric durability isrecognised as a complex phenomenon involving many factors, including the type

of fibre, the yarn geometry and the fabric parameters

In this chapter, the role of fabric construction in durability is discussed Varioustypes of fabric constructions are studied and their different geometric parameterssubmitted for consideration Fabric durability is so complex a mechanism that theeffect of one factor is often masked by interactions with others This chapterdiscusses the geometric aspects of textile materials and their influence on durabil-ity, and points out problems that require further investigation

Different levels of textile materials structure, i.e fibre level, yarn level, and fabricconstruction level, can be applied to fabrics that are not homogeneous isotropicmaterials Figure 1.1 shows that there are three main types of fabrics: woven,knitted and nonwovens As indicated in Fig 1.1, these may be further subdividedinto several classes Fabrics represent a two-phase system of air and fibre Fibresand/or yarns, and sometimes other materials, are components of a fabric construc-tion In a typical yarn, each fibre is helically twisted, or compacted by other means,into a cylinder of varying hardness with other rod-like fibres that differ somewhat

in diameter, length, cross-section and morphology Conventional woven fabrics oftwo-dimensional (2D) structure are made by interlacing two sets of yarns at rightangles to each other The yarns running along the cloth length are called the warp;the yarns in the perpendicular direction, the weft The weave, together with yarnlinear density and thread spacing, determines the construction of woven fabric.There is a very large variety of weaves in woven fabrics, but plain, twill and satinweaves are the basic (elementary) weaves that are widely applied in a great number

of single woven fabrics In the plain weave structure, as shown in Fig 1.2(a), eachwarp yarn interlaces with each weft yarn alternately, on the one-up/one-down

1.1 Main types of fabric construction.

principle Thus the plain weave represents the closest possible interlacing of warpand weft In twill weaves, the warp or weft floats on the surface of the fabricproducing a diagonal pattern (Z or S twill lines) Figure 1.2(b) shows a 1/3 twillweave with a Z twill line The twill lines are produced by allowing all the warp ends

to interlace in the same way, but displacing the interlacing points of each end byone pick relative to that of the previous end Satin weaves have long yarn floats(over four yarns minimum), with a progression of interlacing by a defined number(over two yarns minimum) If the warp covers the surface, as shown in Fig 1.2(c),the fabric is called warp satin cloth When weft yarns predominate on the face ofthe fabric (see Fig 1.2(d)), sateen is produced, a weft-faced fabric Other classes

of weaves are derivative, combined and complex weaves Besides the mentioned single fabrics, there are compound woven fabrics, e.g double, treblecloths, tubular fabrics, pile fabrics, three-dimensional (3D) fabrics and tri-axialfabrics

above-Knitted fabric can be made by inter-looping from a single yarn or an assembly

of yarns In a knitted structure, the basic element is a needle loop The knitted stitch

is the basic unit of inter-meshing and there will usually be three or more intermeshedneedle loops in a knitted stitch Knitted structures may be composed of stitchescontaining both open and closed loops

Woven fabrics

Single woven fabrics

Compound woven fabrics

1.2 Weaves of woven fabrics: (a) plain; (b) 1/3 twill; (c) 8-end warp

satin; (d) 8-end sateen.

Figure 1.1 shows the two classes of knitted structures: weft knitted fabrics andwarp knitted fabrics As shown in Fig 1.3, a weft knitted fabric is constructed from

a single yarn, with the loops made horizontally across the fabric There are threebasic structures of weft knitted fabrics: plain pattern, rib pattern, and purl knitpattern There is also a wide range of weft knitted derivatives, but the knit-misspattern and the interlock pattern are the most widely used Warp knitted fabric, asshown in Fig 1.4, is a vertical loop construction made from one or more sets ofwarp by forming loops There is a large variety of warp knitted fabrics Pillar stitch,single (bar) tricot stitch, and atlas are the simplest one bar warp knitted structures

A wide range of knitted fabrics can be made on several bar warp knitting machines.Directionally oriented warp knitted fabrics (see Section 1.4.2), 3D knitted fabrics(see Section 1.6), and a great number of other knits are textile materials of complexstructure In addition to the above-mentioned woven and knitted fabrics, sometextile structures have a combined woven–knitted construction consisting ofalternating woven and knitted stripes

Nonwovens are another type of textile structure In the current study, this term

is applied generically to textile materials made from a web of fibres only, or fromfibres and sets of yarns (such as Maliwatt or Malimo), or from fibres and a bondingagent and by other unconventional methods Both web formation and bonding maytake several forms Homogeneous and heterogeneous nonwovens, and materialswith isotropic (random) and anisotropic structures are widely used

Figure 1.1 shows the main classes of nonwovens: stitchbonded fabrics, sive-bonded fabrics, spunbonded fabrics, spunlaced fabrics and needlebonded(needlepunched) fabrics Additional new production technologies have also intro-duced new nonwoven structures One example of such a structure (Maliwatt)consists of using warp knitting technology units to stitch a fibre web with yarn.Another stitchbonded structure (Malimo) uses three sets of yarns in which the warpand weft sets are stitched together using a third system consisting of sewingthreads In adhesive-bonded fabric structures, webs of fibres are strengthened by

1.3 Schematic construction of weft knitted fabric (example of plain

adhesive, thermobonding, or needlepunching Spunlaced fabrics are made by theentanglement of fibres in the web by means of high-pressure water streams.Needlebonded fabrics may be produced by using a web of fibres of various typesand blends, which are interlocked by using needles to transfer the fibres.

In addition to woven, knitted and nonwoven fabrics, various other combinedforms should be noted These include coated textile materials, multilayer textilepackets and laminated structures, some of which are likely to be of futureimportance

1.2.1 Characterising different fabric structures

Because woven fabrics, knitted fabrics, and nonwovens may be composed ofvarious types of fibres and systems of yarns, or other components used forcovering, laminating or special finishing (e.g antistatic, flame-retardant, breath-able), a large number of indices are applicable to fibres, yarns and fabrics Theproperties of fibres are determined by the nature of their chemical composition, bythe fine molecular structure of the constituent polymer and by the externalstructure of the fibres One of the main factors that can affect the properties of yarn

is the fibre and yarn geometry The geometrical factors of fibre linear density, fibrelength, yarn linear density and yarn twist are particularly important Additionalinformation on a variety of characteristics that define the geometry of various

fibres and yarns is given by Hearle et al (1969), Hongu and Phillips (1997), Lawrence (2003), Hongu et al (2005), Petrulis (2009), Chen and Hearle (2010),

Grishanov (2010) and Ognjanovic (2010)

Fibres are used in the form of spun yarns, filament yarns or webs in themanufacture of various types of fabrics The main construction indices of woven,knitted and nonwoven fabrics are given below The parameters used in themanufacture of woven fabrics are the linear densities (count) of the constituentyarns (warp and weft), the warp and weft sets and the weave These factors and thefabric manufacturing conditions (tension control parameters, etc.), taken togetherwith other properties of the yarns, affect the parameters of grey fabric (i.e fabric

in the loom state) construction These fabric construction parameters include clothdensities in the warp and weft directions, the crimp of the warp and weft, variousindices of cover factor, the fabric area density (mass per unit area) and thethickness of the cloth The sources for woven fabric construction are studies by

Hearle et al (1969), Zurek and Kopias (1983), Hu (2004), Chen and Hearle (2010)

and Vidal-Salle and Boisse (2010)

The construction of knitted structures is characterised by the shape and size ofloops, the linear density of the constituent yarns and the type of tricot structure Thevalues of the loop width and height, the loop shape factor and other parameters, areused to analyse the loop geometry Other important indices of knitted fabricconstruction are the cover factor (tightness), stitch density (i.e wale density,course density and the total number of loops in a measured area of knitted fabric),

area density, and thickness Additional data on the construction indices of knitted

structures are given by Hearle et al (1969), Spencer (2001), Chen and Hearle

(2010) and Kyosev and Renkens (2010)

Indices of area density and thickness, data on the uniformity of nonwovens andvarious indices of their integral parts or layers and connecting (bonding) param-eters may be applied when characterising the construction of nonwovens Fibreorientation in the web and the fineness, cross-sectional shape, length and crimpparameters of fibres are important factors in a great number of nonwovens Thestructural parameters of bond points include the bonding area, bond point distribu-tion, bonding shape and bonding density More data about nonwoven structures

and their characteristics are given by Hearle et al (1969), Jirsak and Wadsworth (1999), Magel and Bieber (2003), Magel et al (2003) and Mao and Russell (2010).

In more complex or specific textile structures, for example compound fabrics andcombined forms of nonwovens, additional construction parameters may be sug-gested

The indices of textile material construction, including area density and ness, are different after finishing when compared with those of grey products.Therefore, knowledge of the construction characteristics of finished materials isessential for understanding the durability properties of the final products This may

thick-be applied not only for newly finished materials, but also after a period of wear.These changes of fabric construction can be characterised by parameters ofdimensional stability

1.3 Fibre and yarn properties that affect fabric

durability

Fibres, which are polymeric materials, are the main elements of all types of fabrics

To resist destruction, fabric must be capable of absorbing the energy imparted to

it by the application of stress and releasing this energy upon removal of the stress,without any failure occurring In other words, the fundamental physical properties

of materials govern their ability to absorb and return energy To eliminate theeffects of form factor on samples investigated during experimental studies, fila-ment yarns with a minimum of twist were used (Hamburger, 1945) Similarly,much complexity is eliminated if the fabric specimen is constructed from mono-filament yarns (Backer and Tanenhaus, 1951)

Dimensional stability, tensile properties, friction, and fatigue phenomena areamong the important durability properties of polymeric materials Saville (2000)believes that there are a number of different causes of dimensional change In thatstudy, the following types of dimensional change connected with fibre behaviourare mentioned: hygral expansion, relaxation shrinkage, swelling shrinkage, and

felting shrinkage Additional information on this subject is given by Abbott et al.

(1964) and Cookson (1992)

Load–elongation diagrams of mechanically conditioned specimens were used

by Hamburger (1945) for predicting the inherent abrasion resistance of textilematerials In that study, the desirable stress–strain properties of a fibre formaximum abrasion resistance were listed as follows: low modulus of elasticity;large immediate elastic deflection; high ratio of primary to secondary creep; andhigh rate of primary creep Gagliardi and Nuessle (1950) also have stressed theimportance of fibre elongation as a requisite for higher abrasion resistance infabrics McNally and McCord (1960) believe that for good abrasion resistance, thevalues of fibre elongation and elasticity are more important than strength.Elastic and visco-elastic properties, in particular, together with fibre-to-fibrefrictional properties, are the main cause of fabric bagging (Hunter, 2009a).Resistance to bagging deformation increases with an increasing fibre initialmodulus Recovery from deformation depends mainly upon the elastic and visco-elastic properties of the fibres Friction, surface cutting, and fibre plucking arementioned by Backer (1951) in a study of the mechanics of fabric abrasion.Friction and surface cutting cause direct damage to the fibre at its points of contactwith abrasive particles Plucking may cause an immediate or dynamic fatiguerupture of the fibre at the point in the fibre length where the maximum stressconcentration occurs Frictional adhesion at the textile material surface may result

in secondary damage to the fabric that far exceeds the direct effects of frictionalwear This indirect damage is caused by the transmitting of frictional forces alongthe length of the surface fibres and is evidenced in the tensile or bending fatigue ofthe fibre or in its removal from the yarn

Pills are formed by a rubbing action on loose fibres present on the fabric surface(Saville, 2000) The greater the breaking strength and the lower the bendingstiffness of the fibres, the more likely they are to be pulled out of the fabricstructure Hunter (2009b) believes that stronger and higher-elongation fibresgenerally lead to a greater degree of pilling Other studies deal with the interactionbetween types of polymer and the durability of textile fibres or yarns Thomsonand Traill (1947) studied the flexural endurance of several fibres The results of thestudy are not strictly comparable since the stresses developed in the fibres varywith their diameter, but the superiority of wool and polyamide and the poorperformance of cellulose acetate, casein and glass fibre are notable A study made

by Hicks and Scroggie (1948) found that the abrasion resistance of yarns increased

in the following order: acetate rayon, normal viscose rayon, medium-high-tenacityviscose rayon, acrylic, and polyamide High abrasion resistance in polyester was

reported by Amirbayat and Cooke (1989) Ozdil et al (2009) also noted that

synthetic fibres such as polyester, polyamide fibres or elastane filaments, increasethe abrasion resistance of a textile material The resistance of wool, which was alsostudied in this paper, was found to be higher than that of acrylic Elastane, whichhas good recovery properties, will also favourably affect the bagging performance

of textiles (Hunter, 2009a)

The durability of blended structures with two components, as well as those withnovel fibres, has also been studied (Candan and Onal, 2002) In this study, knits

from a blend of 50% cotton/50% polyester spun yarns tended to show a greater

tendency to pill than did knits using cotton spun yarns Kalaoglu et al (2003)

investigated the abrasion properties of two variants of 50% wool/50% polyesterblended fabrics, the spun yarns of which were made from a novel polyester fibrewith a special channelled contour, and conventional polyester fibre The resultssuggested that the novel polyester fibre caused a slight decrease in the resistance ofthe fabric to abrasion

One more group of factors affecting fabric durability is that of fibre geometry.The influence of fibre diameter, length and crimp has been widely studied Finch(1951), in a study of inter-fibre stress and its transmission, showed that thegeometrical area of individual fibres depends upon the normal load at the point ofcontact, the principal curvatures of the fibre, the contour of the fibre cross-sectionand the fibre bulk modulus The bulk modulus is a major factor in fabric structures,influencing the contact area under a given load The local load at a fibre point will

be smaller where the bulk modulus is low As local load is reduced, the actual area

of contact at each point is also reduced and the abrasive protuberance will descendinto the yarn structure to a lesser degree Increasing the fibre diameter up to a limitimproves the abrasion resistance (Saville, 2000) Similarly, in spunbondednonwoven fabric (Kothari and Das, 1993), a fine fibre may bend under a lower loadthan a coarser fibre and, as a result, fabric made of finer fibres should have a higherdegree of compressibility The propensity to pilling decreases when the fibre

diameter is increased (Beltran et al., 2006b) because stiffer fibres are more

resistant to entanglement (Hunter, 2009b) Fabrics made from bulked continuousfilament yarns are particularly susceptible to the formation of snags (Saville,2000) These are loops of fibres which are pulled from a fabric when it comes intocontact with a rough object Longer fibres incorporated into a fabric confer betterabrasion resistance than shorter fibres because they are more difficult to removefrom the yarn For the same reason, filament yarns are more resistant to abrasionthan staple yarns made from the same fibre Thus, for example, longer polyester

and combed cotton improve abrasion resistance (Bhortakke et al., 1997) Hunter

(2009b) claims that longer fibres are generally preferable in terms of pilling Anincrease in fibre crimp is also generally associated with a reduction in fabricpilling

1.3.1 The effect of yarn structure on fabric durability

The values of yarn geometry and yarn properties have been widely studied, withthe intention of showing their effect on durability characteristics, especially those

of abrasion resistance, compressibility, bagging and pilling performance Currentstudies include durability tests on yarn sheets and on the durability of fabrics madefrom different types of yarns Yarn twist, yarn diameter, yarn ply, and otherparameters of yarn geometry have been studied as factors impacting upon fabricdurability

Morton (1948) believed that for good wear resistance, any tearing-out action isreduced by firm binding of the fibres This increased cohesion may be achieved inboth filament and spun yarns through increasing their solidity by means of agreater number of twists The effect of twists on a sheet of yarns was examined byHicks and Scroggie (1948) In this research, the abrasion resistance reached amaximum with an increased number of twists A decrease in durability at a lowernumber of twists is thought to be due to the ease with which snagging or pickingmay occur in filaments that are only loosely intertwined with each other Where

there is a higher number of twists, the durability decreases, which may be due to an

increasing movement of components in the direction of the wheel path

Evaluations of wear resistance in fabrics differing only in yarn twist have beencarried out by Backer and Tanenhaus (1951) These tests showed a very slight,though consistent, improvement in fabric wear as the value of the twist factor ofeither the warp or weft yarn was increased It is important to note that the use of alower number of twists is an alternative method of increasing the contact between

individual yarn crowns in a woven structure and the abradant So the compressive

properties of a yarn and its cohesion play a dual role in determining abrasionresistance as the number of twists is altered These results accord with the finding(Saville, 2000) that there is an optimum amount of twist in a yarn which will givethe best resistance

Beltran et al (2006b) examined pilling in fabrics made from wool yarns.

According to that study, the propensity towards pilling decreases with an increase

in the twist factor of a spun yarn However, at the highest twist level, there is littlefurther effect on pilling (Hunter, 2009b) Stankovic and de Araujo (2010) exam-ined the effect of twists in cotton yarn on compression in knitted fabrics, finding it

to be the result of complex interactions of yarn bulk and residual torque.Yarns with increased twist may be used to improve the bagging performance offabrics (Hunter, 2009a) Smooth yarns with low hairiness exhibit better baggingperformance

The association of greater wear life with increased thickness of a given materialhas been reported many times For instance, important data on the abrasion ofvinylidene monofilaments have been reported by Backer and Tanenhaus (1951).Two series of experiments on multi-filament yarns were discussed by Hicks andScroggie (1948) One series was concerned with the abrasion testing of yarns ofdifferent linear densities but with the same linear density per filament The increase

in abrasion life with increased linear density was thought to be due to the largenumber of filaments that must be abraded before a single yarn failure would occur

in a given yarn sheet The indications were that these results are in accordance withthe generic experience which shows the abrasion resistance of fabrics made fromcoarser yarn to be considerably greater than that of fabrics made from finer yarn.Another series of results is given to show the effect of filament linear density in ayarn Fine-filament yarns have poorer wearing properties than coarser-filament

yarns Kretzschmar et al (2007) and Ozdil et al (2009) also noted that the use of

coarse yarns improves abrasion resistance However, an increase in linear density

increases the tendency to pilling (Beltran et al., 2006b) Hunter (2009b) affirms

that although there is conflicting evidence concerning the relationship betweenyarn linear density and pilling propensity, the balance of evidence indicates thatfiner yarns produce less pilling if all other factors are constant Abrasion resistance

in plied yarns depends upon the number of plies, as well as on the yarn size.Abrams and Whitten (1954) have shown the resistance of a two-ply yarn to beapproximately five times that of a single yarn of equal linear density Plying alsotends to decrease the propensity to pilling (Hunter, 2009b)

In recent years, the wear behaviour of textiles made of a variety of spun yarnstructures, e.g sirospun yarns, ring yarns, compact yarns and open-end yarns, has

been intensively investigated Kalaoglu et al (2003) studied the abrasion

charac-teristics of wool/polyester blended fabrics and compared two-strand sirospunyarns and two-fold ring yarns The samples made from sirospun yarns were found

to wear faster than the samples from ring yarns, but the differences in their masslosses and structural degradation (SEM views were taken) were not significant

Alpay et al (2005) examined the colour differences and percentage reflectivity

changes that occur in dyed cotton woven fabric after abrasion In this study, ringand open-end spun yarns were used in the weft direction and, in many cases, onlyslight differences were observed However, fabric with thicker open-end spun weftyarn was more affected than that with thinner open-end spun weft yarn In threesamples with different yarn twists, it was observed that the smallest colourdifferences occurred in weft yarn with the highest twist, and the greatest colourdifferences occurred in weft yarn with a medium twist value when compared withthe wefts of the other two Fabric with two-ply weft yarn was more affected thanfabric made from a single yarn The percentage reflectivity and colour differenceare less obvious in samples with regular spun yarns, e.g ring spun yarns

In studies by Ozdil et al (2005) of fabrics made from compact spun yarns and

ring spun yarns, compact spun yarns were found to exhibit a better pillingperformance Similarly, Omeroglu and Ulku (2007) found that fabrics manufac-tured from compact spun yarns had better pilling and abrasion resistance than thoseproduced from ring spun yarns Fabrics made from compact spun yarns alsoexperienced a lower loss of mass when compared to those produced from ring spunyarns This is explained by the different degree of hairiness of the yarns Akaydinand Can (2010) pointed out that the fibres of compact spun yarns hold togethermore tightly within the yarn structure as they have a more dense and close structurethan ring spun yarns As a result, the fibre movements that cause abrasion andpilling are limited Therefore, the abrasion resistance and pilling performance offabrics produced from compact yarns are higher than those made from ring spun

yarns Candan et al (2000) concluded that because the hairiness of cotton ring

spun yarns is higher than that of open-end spun yarns, the fabrics from ring spunyarns tend to pill more This trend is in line with the observations of Candan andOnal (2002)

The wear properties of fabrics manufactured from ring carded, ring combed andopen-end rotor spun yarns have been studied by Can (2008) In this study, theabrasion resistance and pilling performance of fabrics made from open-end rotorspun yarns had a maximum value, while the same performance factors of fabricsproduced from ring carded spun yarns had a minimum value Can (2008) believesthat hairiness is the characteristic quality of yarn that affects abrasion resistanceand pilling, i.e an increase in yarn hairiness reduces fabric abrasion resistance andpilling performance Hunter (2009b) indicates that air-jet and rotor spun yarns

perform better than ring spun yarns in terms of pilling Kretzschmar et al (2007)

noted that the type of manufacturing (compact or conventional ring) and the twistcoefficient of spun yarn did not have a significant effect on the abrasion resistancevalues of knitted fabrics However, the pilling values of fabrics knitted withcompact spun yarns were better than those produced with ring spun yarns Pillingvalues also improve when the twist of the yarn is increased Trends in pilling havebeen explained by the low hairiness values of compact spun yarns and of highlytwisted yarns

In several studies, the wear properties of textile materials made from fancy yarnswere examined to determine the effect of yarn factors Nergis and Candan (2003)tested the abrasion resistance and pilling performance of plain knitted fabric madefrom fancy (chenille) yarns The study showed that yarn properties, i.e the lineardensity of component yarns and pile length, do not influence the pilling perform-ance of the samples In dry relaxed fabrics, the loss of mass tended to increase as

the pile length increased and the component yarn became finer Ulku et al (2003)

noted that in chenille fabrics, the average mass loss has a tendency to decrease with

an increase in twist level and pile length Ozdemir and Ceven (2004) studied theinfluence of the manufacturing parameters of chenille yarns on the resistance ofyarn and upholstery fabric to abrasion The yarn twist and pile length were found

to have a significant effect Chenille yarns with high twist levels will undergo lessabrasion than yarns with low twist levels Yarns with longer pile lengths are moreresistant to rubbing than those with short pile lengths

fabric structures

A considerable number of studies have been devoted to the wear process in variousfabric constructions, e.g woven fabrics, knitted fabrics and nonwovens In thesestudies, the main trends in the properties of durability under deformation indifferent directions, abrasion resistance, flexing and fatigue resistance are given.1.4.1 Durability of woven fabrics

Woven fabrics are the most widely studied structures In woven fabric, neither thewarp nor the weft is straight so depending on its linear density, tension, flexural

1.5 Schematic construction of woven fabrics: (a) biaxial type (example

of plain weave sample); (b) triaxial type.

rigidity and warp and weft sets, the yarn is woven in a wavy configuration.Therefore, the behaviour of woven fabric during wear is more complex whencompared with that of yarn or fibre Figure 1.5 shows two types of woven fabricconstruction A biaxial type is produced in conventional plain weave fabric withtwo sets of yarns (warp and weft), as shown in Fig 1.5(a) Biaxial woven fabricsare rather anisotropic materials, i.e resistance to deformation differs in the warp,weft and diagonal directions Figure 1.5(b) shows a triaxial type This type offabric is composed of three systems of yarn (two of warp and one of weft), whichintersect and interlace at an angle of 60° with each other Triaxial fabrics are lessanisotropic than biaxial wovens (Scardino and Ko, 1981) Therefore the perform-ance and lifetime of these textile products may be improved by eliminating theweakest direction and the extremely low resistance to deformation The isotropy ofmechanical properties, especially of shear resistance, is the main quality of triaxialfabrics Asayesh and Jeddi (2010) studied the modelling of creep behaviour inplain woven fabrics The study focused on the use of the yarn creep property andthe construction–mechanical parameters of the fabric Samples of different weftdensities were studied along the weft direction and it was found that an increase inweft density caused a decrease in fabric creep This is due to an increase in thenumber of fabric yarns in the load direction as the weft density increases Thisresults in each yarn bearing a small fraction of the total load

In studies of abrasion and pilling in woven fabrics, the cohesion factor, crimpfactor, weave factor, and other influences have been examined The main trendsare given below

Cohesion in woven fabrics may be achieved by the use of higher sets and closerweaves Tait (1945) noted that in constructing fabrics in which warp yarns areexposed at the surface of wear, the following important conclusions can be made:increased warp densities (at constant weft densities) will furnish greater durability;increased weft densities (at constant warp densities) result in increased fabriccohesion and greater durability A similar trend has been demonstrated by Kalaoglu

et al (2003), viz denser fabrics tend to abrade less than open structures Backer

and Tanenhaus (1951) reported that the geometrical area of contact between a

fabric and an abradant determines the rate of fabric attrition The simplest solutionfor fabric designers is to use higher cover factors and equal crown heights in thewarp and weft yarns Increased cover factors may be achieved through higher clothdensities or greater linear densities in the yarns However, if the fabric densities areincreased excessively, yarn mobility will be severely reduced and rigidprotuberances will form that will not absorb abrasive energy without causingpremature failure in the surface fibres.

Hunter (2009b) notes that the tighter and more compact the fabric, the lower thepropensity to pilling In these structures it is more difficult for fibres to migratefrom the body of the fabric to its surface as a more tightly constructed fabricreduces the ease with which fibres can become detached from the fabric Peirce(1947) spoke of avoiding the ribbed effect by control of fabric construction inorder to enhance its abrasion resistance qualities Backer and Tanenhaus (1951), in

a study of abrasion resistance, discussed the effect of yarn crimp factor High crimp

in a given direction will project yarns in that direction towards the abradingsurface So highly crimped yarns will undergo greater damage, while a protectedyarn system suffers less With the importance of crimp distribution thus estab-lished, it is conceivable that the wear characteristics of woven fabric can be altered

by any factor which will modify the crimp balance Comparisons of fabrics with ahigh warp crimp in the weaving machine state with fabrics in the finished state inwhich the warp crimp has been significantly reduced, show significant changes inwear performance Where the stresses are sufficient to reduce the crimp in eitherdirection, modified wear may result It may therefore be expected that a fabricwithout over-all dimensional stability will be unsatisfactory in laundering, press-ing and subsequent wear

The abrasion resistance of fabrics of different weave types have been examined

by Backer and Tanenhaus (1951), Kalaoglu et al (2003) and Kaynak and

Topalbekiroglu (2008) From the study by Backer and Tanenhaus (1951) it may beseen that the warp breaking strength of twills is significantly reduced afterreciprocating warp-wise (face up) abrasion However, when the fabrics are re-versed, the only material that demonstrates almost complete warp protection,under the conditions of abrasion used, was sateen with the maximum weft floatlength The wear resistance of fabrics of 2/1 twill weave with twill line running up

to the right (Z twill line) and also left-hand twill (S twill line) was also tested Nodifference was noted between the wear score of the left-hand twill and a compara-

ble fabric in right-hand twill Kalaoglu et al (2003) noted that warp faced (twill

weave 2/1) fabrics were more resistant to abrasion than 2/2 twills In this case,samples of fixed area density (200 g/m2) were compared Kaynak andTopalbekiroglu (2008) indicated that long yarn floats and a low number ofinterlacings decreased the durability of woven fabrics by increasing the mass loss.According to Hunter (2009b), plain weave fabrics are generally the least prone topilling, which increases with a decrease in the density of yarn cross-over points and

an increase in yarn float length

Aspects of yarn diameter as an important element in woven construction werediscussed by Backer and Tanenhaus (1951) The application of overly large-diameter yarns in one direction and small-diameter yarns in the perpendiculardirection was found to result in the lighter set bending freely while the heavier andstiffer set remained uncrimped This leads to a reduction in the geometric area ofcontact and to early damage of the exposed, lighter yarns The large diameter of theabrasion-bearing yarns must be accompanied by yarn uniformity if increased wearlife is to be obtained Non-uniform heavy yarns act as focal points in fabricdegradation because of the high concentrations of pressure which occur at theircrowns.

Amirbayat and Cooke (1989) studied the surface properties of a series of wovenfabric samples during abrasion In order to compare the resistance of the differentsamples in relation to their thickness and area density, the corresponding values of

N/T and N/W were calculated, where N is the number of abrasion cycles needed to produce two broken yarns, T is the fabric thickness, and W is the fabric area

density The samples were divided into groups according to their raw material andweave Polyester and its blends, and fabrics other than twill weaves, showed a

higher level of endurance per unit thickness (N/T) than the overall average The number of cycles required to cause abrasion per unit area density (N/W) showed no

significant difference between different structures Amirbayat and Cooke (1989)also reported that the number of abrasion cycles required to cause damage to afabric has a positive correlation with its thickness and area density This conforms

to the analytic conclusions of Backer and Tanenhaus (1951) The flexing of textilematerials in the absence of an external abrasive surface may involve elements ofinternal abrasion between structural components of the fabric as well as elements

of axial tensile and repeated bending stresses (Backer, 1951) In these stances, damage is caused by the relative movement of fibres within the yarns and

circum-of yarns within the fabric As noted by McNally and McCord (1960), in instanceswhere the main cause of mechanical failure in service is surface abrasion, the use

of dense or tight structures should serve to prolong wear life However, when aconsiderable amount of flexing occurs, the use of this construction may result inpremature failure

Amirbayat and Bozzalta (1995) studied the surface attrition of worsted fabrics.The initial fabrics differed in thickness, area density, warp and weft densities,roughness and composition It was found that the initial roughness, thickness, andarea density had no significant effect on the number of cycles needed to impart an

odd appearance to a fabric Manich et al (2001) studied the abrasion of wool and

blended fabrics In this study, the initial mass loss rate and the mean value of thisrate throughout 5000 abrasion cycles (the mean abrasion gradient) appear to begood estimates of the degradation caused by the surface and structural abrasion ofwool and blended wool fabrics A strong relationship with the structural param-eters of the fabrics was shown The initial rate of mass loss increases with the woolthickness and area density of the fabric, and decreases with the fineness and

number of ply threads per yarn The mean abrasion gradient increases with the areadensity of the fabric, the interlacing coefficient and the yarn linear density It

decreases with the number of ply threads per yarn Shanbeh et al (2010) studied

the reflectance factor and colour of chenille woven fabrics after abrasion It wasfound that the reflectance factor and colour differences of fabrics with higher weftdensity were more affected by abrasion at all levels

1.4.2 Durability of knitted fabrics

Conventional knitted fabrics are less stable than woven fabrics They are producedusing low twist yarns and have a slack construction For this reason, the loops ofweft knitted structures tend to distort easily under a fairly low degree of tension.Single guide bar fabrics are also very unstable structures and most warp knittedstructures are therefore produced from two or more sets of warp threads (Spencer,2001) Directionally oriented warp knitted fabrics are important materials in terms

of dimensional stability at different directions The fabrics consist of multiplelayers of yarns, differently arranged and stitched together The most commonlyused types (see Fig 1.6) are uniaxial, biaxial, triaxial, and quadraxial fabrics inwhich straight, uncrimped yarns are aligned in one or more directions to providemulti-directional in-plane properties For instance, in biaxial knitted fabric (seeFig 1.7), two layers of yarns, one at a direction of 0° and another at 90°, areconnected using tricot structure Figure 1.8 shows a quadraxial knitted fabric inwhich the layers of yarns, which are arranged in directions of 0°,+45°, 90° and–45°, are stitched by means of warp knitting technology units Some details on themanufacturing of these structures are given by LIBA (2007; 2008) Knitted fabricswith directional behaviours are used as reinforcement materials for composites orgeogrids (Lazar, 2010) as the additional layers of yarns act as load-bearing systemswithin the knits

Abrasion resistance and pilling performance are the main durability factors forknitted fabrics in the following studies Pamuk and Ceken (2008) examinedvarious textile materials used for automobile seat covers In this research, samples

of circular knitted flat, circular knitted pile, warp knit flat, warp knit pol and warpknit double bar raschel were studied The warp knit double bar raschel showed thehighest abrasion resistance Akaydin (2009) studied the abrasion resistance ofthree knitted fabrics: jersey, rib and interlock structures The interlock and jerseyfabrics were found to have the best and the least resistance, respectively Akaydinand Can (2010) tested the abrasion resistance and pilling performance of jersey andinterlock fabrics The abrasion resistance and pilling performance of interlock

fabrics were found to be higher than those of jersey fabrics Beltran et al (2006a;

2006b) evaluated the influence of several fibre-to-fabric input parameters onpilling in woollen knitwear and found fabric cover to be the factor with the greatesteffect on pilling According to this research, the propensity to pilling decreases

with an increase in the fabric cover factor Kretzschmar et al (2007) noted that the

1.6 Arrangement of yarn sets in directionally oriented warp knitted

fabrics: (a) and (b) uniaxial type; (c) and (d) biaxial type; (e) and (f) triaxial type; (g) quadraxial type.

abrasion resistance values of interlock knitted fabrics were higher than those of riband plain jersey fabrics In a pilling test, interlock knitted fabrics showed a highpilling tendency in comparison with rib and plain jersey fabrics

Although the applications of nonwovens have expanded into various areas, theunderstanding of their durability is still limited The durability properties ofnonwovens are determined by the properties and structural arrangement of their

components As noted by Hearle et al (1969), there is an obvious analogy between

felt and spun yarns The structure of both yarns is composed of short fibres and

1.7 Biaxial warp knitted fabric.

1.8 Quadraxial warp knitted fabric.

100 mm

100 mm