This article was downloaded by: [182.186.134.123]On: 09 April 2015, At: 19:55Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Click for updates

The Journal of The Textile InstitutePublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/tjti20

Modeling the effect of elastane linear density, fabricthread density, and weave float on the stretch,recovery, and compression properties of bi-stretchwoven fabrics for compression garmentsMuhammad Maqsooda, Tanveer Hussainb, Mumtaz Hasan Malikc & Yasir Nawaba

a Department of Weaving, National Textile University, Faisalabad, Pakistanb Department of Textile Processing, National Textile University, Faisalabad, Pakistanc Department of Yarn Manufacturing, National Textile University, Faisalabad, PakistanPublished online: 07 Apr 2015.

To cite this article: Muhammad Maqsood, Tanveer Hussain, Mumtaz Hasan Malik & Yasir Nawab (2015): Modeling the effectof elastane linear density, fabric thread density, and weave float on the stretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments, The Journal of The Textile Institute, DOI: 10.1080/00405000.2015.1029809

To link to this article: http://dx.doi.org/10.1080/00405000.2015.1029809

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Modeling the effect of elastane linear density, fabric thread density, and weave float on thestretch, recovery, and compression properties of bi-stretch woven fabrics for compression

garments

Muhammad Maqsooda*, Tanveer Hussainb, Mumtaz Hasan Malikc and Yasir Nawaba

aDepartment of Weaving, National Textile University, Faisalabad, Pakistan; bDepartment of Textile Processing, National TextileUniversity, Faisalabad, Pakistan; cDepartment of Yarn Manufacturing, National Textile University, Faisalabad, Pakistan

(Received 21 December 2014; accepted 2 March 2015)

The aim of this study was to investigate the effect of elastane linear density, thread density, and weave float on thestretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments. Fabric samples wereproduced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric threaddensity, and weave float size were used as input variables while fabric contraction, subgarment pressure, fabric stretch,and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 and 78 dtex, two differentthread densities, and three different weave designs, i.e. 1/1 plain, 2/2 z-twill, and 3/3 z-twill were used. The results offabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R-sq values) of theregression equations showed good prediction ability of the developed statistical models. The findings of the study maybe helpful in deciding appropriate manufacturing specifications of bi-stretch fabrics to attain specific stretch, recovery,and compression properties.

Keywords: bi-stretch; statistical model; stretch; recovery; compression garments

Introduction

Stretchable fabrics have diverse applications rangingfrom casual apparel to performance sportswear andcompression therapy. Unidirectional stretch fabrics arestretchable only in one direction whereas bi-stretchfabrics are stretchable in both directions, i.e. widthwiseand lengthwise. In apparel, stretchable fabrics are knownto provide attractive fit, comfort, shape retention, andenhanced athletic performance because of their goodstatic as well as dynamic elastic recovery properties(Sacevičienė, Masteikaitė, Klevaitytė, & Audzevičiūtė,2011). Compression therapy is the universally acceptedtreatment for the management of hypertrophic scarringafter severe burns (Anand, Govarthanam, & Gazioglu,2013b). Stretchable fabrics are also used in compressiontherapy for the treatment of varicose veins, venous legulcers, and hypertrophic burn scars (Schuren & Mohr,2008). Core-spun cotton yarns, with elastane filament inthe core and cotton fibers in the sheath, are commonlyused in the production of woven stretch fabrics. Theelastane core provides the required stretch and recoveryproperties while the cotton fibers in the sheath providetactile comfort characteristics. The mechanical propertiesof stretch fabrics are determined by linear density of theelastane, the count and the twist of the yarn, the fabricweave design and construction, and the finishingprocesses (Su, Maa, & Yang, 2004).

Ozdil has reported the effect of elastane content ofthe core-spun cotton yarns in the weft on the stretch andbagging properties of denim fabrics (Ozdil, 2008).Mourad and Elshakankery concluded that the airpermeability and tearing strength of the fabric decreasesignificantly with the increase in elastane ratio of theconstituent yarns (Mourad, 2012). Bennett found thatafter successive launderings the fabric stretch decreasessignificantly, however, the twill weave fabrics can retainbetter stretch ability even after laundering (McCallaBennett, 1968). Sawhney determined the effect of fabricstructure on the properties of two-way stretch fabricsmade from elastic core-spun yarns of cotton and woolblend. He found that a tighter weave develops lessstretch than an open weave (Sawhney, 1974). Hui andNg developed a model to predict the interfacial pressuresin multilayer elastic fabric tubes with various tensileproperties (Hui & Ng, 2001). Rego, Verdu and Nietoshowed that the fabric weft stretchability due to elastanehas significant influence on tactile comfort as well as onmechanical properties and thermal resistance of thefabric (Rego, Verdu, Nieto, & Blanes, 2009). Kumarexamined the subbandage pressure measurement underdynamic conditions by using an artificial leg-segmentprototype which simulates the dynamic behavior of thelower extremity, i.e. the amount of bending of leg atknee or ankle position, the speed of movement, etc.

*Corresponding author. Email: maqsood@ntu.edu.pk

© 2015 The Textile Institute

The Journal of The Textile Institute, 2015http://dx.doi.org/10.1080/00405000.2015.1029809

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15

(Kumar, Das, & Alagirusamy, 2013). Anand worked onthe modeling and characterization of knitted compressiongarments. He refined the Laplace equation to predict thesubgarment pressure more accurately, irrespective of theshape and size of the limb (Anand, Govarthanam, &Gazioglu, 2013a). Ajayi examined the relations betweenfabric compression and friction. It is found that higherthe fabric compression, the larger is the differencebetween the static and kinetic friction forces (Ajayi &Elder, 1997).

Majority of the studies reported in the literature hasfocused on the investigation of different physical andmechanical properties of unidirectional stretch fabrics.However, there is paucity of literature on bi-stretchfabrics comprising elastane containing core-spun cottonyarns both in the warp and weft. The present study wastherefore undertaken to investigate the effect of elastanelinear density, fabric thread density, and weave float sizeon the fabric contraction, subgarment pressure, fabricstretch, and recovery properties of bi-stretch wovenfabrics for compression garments. This study is part of abroader investigation for the optimization of performanceproperties of bi-stretch woven fabrics used incompression therapy.

Materials and methods

Two different core-spun yarns were used in this study,containing cotton fibers in the sheath and elastanefilaments in the core. Properties of both the yarns aregiven in Table 1. Twelve woven fabric samples wereproduced on sample loom (Evergreen CCI Tech IncTaiwan). Six fabric samples were produced with the yarnhaving 44 dtex elastane in the core while the other sixsamples were produced with the yarn having 78 dtexelastane in the core. Two different fabric constructionsand three weave designs were used in manufacturing ofthese fabric samples. The weave designs used for thesesamples were 1/1 plain, 2/2 z-twill, and 3/3 z-twill. Theobjective was to select those weaves which provideequal stretch in both warp and weft directions. It can beseen in Figure 1 that in all three weaves, yarn float isthe same whether the yarn is passing over the weft or

under the weft, which makes the fabric equallystretchable in both warp and weft direction. Fabricspecifications of these 12 samples are given in Table 2,where factors/variables for this study are elastane dtex(X1), threads per square cm (X2), and float size of theweave (X3). The float size is 1 for 1/1 plain weave, 2 for2/2 z-twill, and 3 for 3/3 z-twill. The weave designs areillustrated in Figure 1. For threads per square cm, thereare equal ends and picks per cm. In Table 2, X2 standsfor threads per square cm on loom, whereas in Table 3X2 stands for threads per square cm after desizing.

All the fabric samples comprised elastane core-spunyarns both in the warp and weft directions. Afterweaving, all the fabric samples were desized together onMini-Jet desizing machine (P-300 Texam Co. Ltd Japan)using Amylases enzyme desizer (4 g/L) at 70 °C for45 min.

After desizing, the samples were relaxed dried in airand then conditioned before testing. The standard testmethod ASTM D 6614 was used to test the stretch%,growth%, and recovery% of the fabric samples both inthe warp and weft directions (“ASTM D6614 - 07(2011)” n.d.). This test was performed on UniversalTensile Strength Tester (LLOYD LRX plus AmetekUSA). Three samples were used for each test and theiraverage values were taken and reported in Table 3.Fabric samples were cut according to the standardmethod. After placing the sample in the jaws of theuniversal tensile strength tester, the jaws were moved ata constant rate of extension. Samples were held at1814 g load for five minutes to give maximum stretch %at 1814 g load and then machine jaws were allowed toreturn to their starting point. Samples were kept underrelaxation in the jaws for five minutes and then fabricgrowth% was measured and finally by knowing thevalues of stretch and growth, recovery percentage of theproduced samples was calculated. Stretch, growth, andrecovery percentages were calculated by Equations (1–3)given below.

Fabric stretch% ¼ B� A

A� 100; (1)

Fabric growth% ¼ C� A

A� 100; (2)

Fabric recovery% ¼ B� C

B� A� 100; (3)

where A is the distance marked between the upper andbottom parts of the fabric, B is the distance between themarked points after holding the sample for 5 min with1814 g load, and C is the distance between the markedpoints after 5 min relaxation.

Fabric’s contraction% was calculated usingEquation (4).

Table 1. Properties of core-spun yarns.

No. Parameters Units Y1 Y2

1 Yarn linear density tex (Ne) 19.7 (30) 19.7 (30)2 Elastane linear density dtex 44 783 Twist per meter No. 885 8854 Tenacity cN tex−1 15.49 12.655 Elongation % 8.15 8.316 CVm % 11.71 11.917 Imperfection index No. 43.3 62.5

2 M. Maqsood et al.

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15

Suitability of bi-stretch woven fabrics forcompression garments was checked by Kikuhime

pressure sensor which is shown in Figure 2. Thisinstrument consists of up to three small pressure sensorsand a digital measuring device. This instrument isaccurate and reliable, and measures the actual pressureexperienced by the wearer (Anand et al., 2013a). Fabricsamples were cut and sewn into loops whosecircumference was 30% less than the circumference ofthe object on which they were worn. Pressure sensorwas placed between the object and fabric sample. Staticpressure was tested while testing the subgarmentpressure. Static pressure of each fabric sample wasdetermined at four different places and their results wererecorded in mmHg.

Results and discussion

Fabric specifications and summary of the test results aregiven in Tables 2 and 3, respectively. All the tests wereperformed three times and their average values were

Figure 1. Weave designs investigated in this study.

Table 2. Fabric specifications.

Sample no. Elastane count (dtex), X1 Threads /cm2, X2 Weave design Weave float, X3

1 44 31.4 1/1. plain 12 44 31.4 2/2. twill 23 44 31.4 3/3. twill 34 44 39.4 1/1. plain 15 44 39.4 2/2. twill 26 44 39.4 3/3. twill 37 78 31.4 1/1. plain 18 78 31.4 2/2. twill 29 78 31.4 3/3. twill 310 78 39.4 1/1. plain 111 78 39.4 2/2. twill 212 78 39.4 3/3. twill 3

Figure 2. A Kikuhime subgarment pressure indicator monitor.

Fabric contraction% ¼ Fabric width on loom� Fabric width off loom

Fabric width on loom� 100: (4)

The Journal of The Textile Institute 3

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15

taken and given in Table 3. The tests were performedunder standard atmospheric conditions, i.e. 20 Celsiustemperature and 65% humidity. The statistical analysis ofthe results was performed using MINITAB 17 statisticalsoftware. The regression coefficients and p-values of allthe terms are given in Table 4. The terms with p-valuesless than 0.05 are considered statistically significant with95% confidence. A higher value of the coefficientindicates higher effect of corresponding term and viceversa. A minus (−) sign indicates that the response valueincreases by decrease in the factor value and vice versa.It is clear from Table 4 that the selected variables, i.e.

elastane count (X1), threads per square cm (X2), andweave float (X3) have significant effect on the resultingfabric contraction%, subgarment pressure, stretch% alongwarp, stretch% along weft, recovery% along warp, andrecovery% along weft. Some interactions of selectedvariables are also statistically significant. The regressionequations, comprising the statistically significant terms,are given in Table 5 for all the response variables. TheR2 values give the percentage of variation in theresponse variables that can be explained by the factors/terms included in the regression equations. Thecorrelation between the response variables is given in

Table 3. Test results.

Sampleno. X1 X2 X3

Off-loomcontraction%

Subgarmentpressure (mmHg)

Stretch%along warp

Recovery %along warp

Stretch%along weft

Recovery%along weft

1 44 55 1 45.1 23.75 94.8 80.6 128.6 74.42 44 67.6 2 60 20.5 116.3 84 150.8 77.93 44 75.9 3 65.2 19.75 126.4 83.2 156.5 81.84 44 64.5 1 40.2 30.5 69 80.3 89.1 78.15 44 72.3 2 47.6 27 87.4 81.4 115.7 80.96 44 84.2 3 57.7 26.25 95.7 87.1 128.8 82.67 78 53.4 1 45.1 24.25 101.2 87.1 106 82.88 78 66 2 57.7 27.5 120.7 85.5 146.6 82.29 78 75.5 3 65.2 27 134.8 89.7 158.2 84.710 78 64.5 1 40.2 38.5 72.7 87.9 89.3 82.211 78 72.3 2 48.8 30 97.3 82.6 116.1 81.812 78 82.6 3 55.1 29.25 116.4 87.9 137.1 82

Table 4. Regression coefficients for different response variables using coded values of the input variables.

Terms

Off-loomcontraction%

Subgarmentpressure(mmHg)

Stretch% alongwarp

Stretch% alongweft

Recovery%along warp

Recovery%along weft

Coeff. p-value Coeff. p-value Coeff. p-value Coeff. p-value Coeff. p-value Coeff. p-value

Constant 56.262 0.000* 25.056 0.000* 115.73 0.000* 143.39 0.000* 84.193 0.000* 80.672 0.000*X1 −0.341 0.439 2.508 0.000* 4.265 0.000* −2.686 0.004* 2.178 0.000* 1.968 0.000*X2 −6.529 0.000* 5.250 0.000* −46.83 0.000* −57.17 0.000* 0.139 0.87 −0.178 0.733X3 8.932 0.000* −1.847 0.000* 42.43 0.000* 52.38 0.000* 1.443 0.020* 1.397 0.000*X2

2 0.202 0.84 0.194 0.663 −35.65 0.000* −12.89 0.187 −1.9 0.536 3.14 0.1X3

2 −2.51 0.020* 1.125 0.018* −16.63 0.000* −15.38 0.000* 0.389 0.667 0.757 0.178X1X2 0.102 0.845 −0.215 0.438 −2.31 0.174 6.08 0.015* −1.611 0.039* −2.649 0.000*X1X3 −0.64 0.244 0.167 0.551 2.38 0.047* −0.54 0.75 0.154 0.771 0.483 0.144X2X3 −0.453 0.484 −1.074 0.002* 42.56 0.000* 18.41 0.062 2.33 0.449 −2.86 0.134

*Statistically significant terms with 95% confidence level.

Table 5. Regression equations for different fabric properties.

Fabric properties Regression equations R2 (%)

Off-loom contraction% 72.25 − 0.0206 X1 − 1.0337 X2 + 8.973 X3 96.10Subgarment pressure (mmHg) −15.44 + 0.1487 X1 + 1.174 X2 − 0.70 X3 + 1.125 X3 × X3 − 0.1705 X2 × X3 89.97Stretch% along warp −75.7 + 0.2594 X1 + 8.37 X2 − 56.2 X3 − 0.1198 X2 × X2 − 16.68 X3 × X3 + 2.474 X2 × X3 96.08Stretch% along weft 335.3 − 1.438 X1 − 5.079 X2 + 81.27 X3 − 13.31 X3 × X3 + 0.01920 X1 × X2 + 0.349 X2 × X3 95.33Recovery% along warp 53.13 + 0.453 X1 + 0.317 X2 + 1.247 X3 − 0.00485 X1 × X2 66.45Recovery% along weft 42.89 + 0.607 X1 + 0.418 X2 + 1.635 X3 − 0.00734 X1 × X2 83.27

4 M. Maqsood et al.

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15

Table 6 which shows Pearson correlation (upper value inthe cell) and p-value (lower value in the cell). It can benoticed in Table 6, the correlation between off-loomcontraction% and subgarment pressure is statisticallysignificant and has strong negative relation, i.e. lower theoff-loom contraction%, greater will be the subgarmentpressure. Stretch% along warp and weft has strongpositive relation with off-loom contraction%, i.e. higherthe off-loom contraction%, greater will be the stretch%along warp and weft. Similarly the correlations betweensubgarment pressure and stretch% along warp and weftare also statistically significant, but they have strongnegative relation with each other. Moreover, the stretch%along warp and recovery% along warp have strongpositive correlation with stretch% along weft andrecovery% along weft, respectively. The effect of all thefactors on each response variable is separately discussedin the following sections.

Fabric contraction

Results of fabric contraction% in off-loom state aregiven in Table 3. It can be seen in Table 4 that amongthree factors (elastane count, threads per square cm, andweave float) two factors, i.e. threads per square cm andweave float, are statistically significant for off-loomcontraction% with 95% confidence, because their p-valueis less than 0.05. Third factor, i.e. elastane count is notstatistically significant. It can be noticed in Figure 3 thatas threads per square cm increases, off-loom contraction% decreases. This may be because of the fact thatgreater number of yarns per square cm offer less freespace for fabric contraction. So off-loom contraction%has inverse relationship with the threads per square cm.Weave float has direct relationship with fabriccontraction. As can be observed in Figure 3, there arethree levels of float, i.e. 1, 2, and 3 and contraction% ismaximum at float 3 (3/3 twill). Greater float means less

Table 6. Correlation between response variables.

Off-loomcontraction%

Subgarment pressure(mmHg)

Stretch%along warp

Recovery%along warp

Stretch%along weft

Subgarment pressure (mmHg) −0.5840.046

Stretch% along warp 0.906 −0.5870.000 0.045

Recovery% along warp 0.367 0.247 0.4130.241 0.440 0.182

Stretch% along weft 0.942 −0.667 0.938 0.2320.000 0.018 0.000 0.468

Recovery% along weft 0.379 0.252 0.358 0.755 0.1480.224 0.430 0.253 0.005 0.646

Note: Cell contents: Pearson correlation (upper); p-value (lower).

Figure 3. Main effect plot for fabric contraction.

The Journal of The Textile Institute 5

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15

number of interlacements during weaving so when thereis less number of interlacements, fabric is less compactand yarns have more freedom to contract. At float 1, i.e.plain weave, contraction% is least because in plainweave yarns have maximum number of interlacementsdue to which they find less space to contract. As it isclear in Figure 3, elastane count range used in this studydoes not have any significant effect on fabriccontraction.

Regression equation for off-loom contraction% isgiven in Table 5. R2 value of the regression equation foroff-loom contraction% is 96.10%.

Subgarment pressure

Test results for subgarment pressure (mmHg) are givenin Table 3. Statistical analysis given in Table 4 showsthat all the three factors (elastane count, threads persquare cm, and weave float) are statistically significantfor sub garment pressure (mmHg) because their p-valueis less than 0.05. Surface plots of sub garment pressure(mmHg) vs. threads per square cm, weave float, andelastane count (dtex) are given in Figure 4. It can beobserved in Figure 4 (left) that greater the elastane count(dtex) and higher the thread density then more will bethe pressure generated by the samples. The reasonbehind is that greater elastane count (i.e. 78 dtex) resultsin greater retractive force which leads to highersubgarment pressure. It can be concluded that elastanecount (dtex) has direct relation with pressure generationby the fabric samples. Threads per square cm also havedirect relation with subgarment pressure generation.Greater the thread density more will be the pressuregenerated by the samples. Because due to greater threaddensity fabric becomes more compact and due to greatercompactness of the fabric, higher retraction force isgenerated when the fabric is held in extended positionwhile worn on a limb of diameter larger than that of thegarment loop.

It can be seen in Figure 4 (right) that greater thethread density and shorter the weave float, then greaterwill be the pressure (mmHg) generated by the samples.So a fabric made from 1/1 weave having threads persquare cm 39.4 will have greater pressure generationthan a fabric made from 3/3 twill weave having threadsper square cm 31.4, because greater thread density andshorter weave float make the fabric more compact due towhich its ability to generate pressure increases. Hence, itcan be concluded that a fabric having greater threaddensity and shorter weave float will generate morepressure than a fabric with less thread density and higherweave float.

Regression equation for subgarment pressure(mmHg) is given in Table 5. R2 value of the regressionequation for subgarment pressure is 89.97%.

Fabric stretch

Results of stretch% along warp and weft of all the fabricsamples are given in Table 3. Statistical analysis given inTable 4 shows that all the three factors (elastane count,threads per square cm, and weave float) are statisticallysignificant for fabric stretch% along warp because theirp-value is less than 0.05. Two of the interactionsbetween factors such as elastane count (dtex) with weavefloat and threads per square cm with weave float are alsostatistically significant for warp-way stretch. Squaredeffects of weave float and threads per square cm are alsostatistically significant. Surface plots of stretch% alongwarp vs. threads per square cm, weave float, andelastane count (dtex) are given in Figure 5. It can beobserved in Figure 5 (left) that warp-way stretch ismaximum when the weave float is longer and thethreads per square cm are lower. For longer weave floatsthere is less number of interlacements per unit area anddue to less number of interlacements per unit area, yarnsare free to move, hence fabric will be more stretchabledue to less number of interlacements. Thread density

Figure 4. Surface plots of subgarment pressure vs. threads per square cm, weave float, and elastane count (dtex).

6 M. Maqsood et al.

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15

(threads per square cm) is another factor whichinfluences the fabric stretch ability. More thread densitydoes not allow the yarns to move freely when load isapplied, hence thread density is inversely proportional tothe stretch ability of the fabric. It can also be noticed inFigure 5 (right) that longer the weave float and higherthe elastane count (dtex) then greater will be the stretch% along warp, because due to higher elastane count(dtex), fabric is more stretchable, the reason is 78 dtexelastane yarn contains more Lycra% than 44 dtexelastane yarn, hence due to greater Lycra% in elastaneyarn, fabric is more stretchable.

Regression equation for stretch% along warp is givenin Table 5. R2 of the regression equation for stretch%along warp is 96.08% which signifies that 96.08%change in the stretch% along warp can be explained bythe terms included in the equation.

Surface plots of stretch% along weft vs. threads persquare cm, weave float, and elastane count (dtex) aregiven in Figure 6. It can be observed in Figure 6 (left)weave float and threads per square cm are the twofactors which greatly influence the stretch% of fabricalong weft. Weave float has direct relation with stretch%along weft while threads per square cm have inverserelation with stretch% along weft. Because longer weave

float allows the yarns to stretch more due to less numberof interlacements and greater thread density restricts theyarns free movement when load is applied. So it can beconcluded that, longer the weave float and lesser thethreads per square cm then greater will be stretch%,along weft. It can also be noticed in Figure 6 (right) thatthe interaction of elastane count (dtex) and threads persquare cm greatly influences the stretch% of fabric alongweft. It shows the inverse relation between the stretch%along weft and the threads per square cm, becausegreater thread density restricts the yarns free movementwhen load is applied. But when elastane count (elastaneratio) is increased in weft yarn its stretch % is decreased.El-Ghezal and Babay also found the same trend in theirstudy (El-Ghezal, Babay, Dhouib, & Cheikhrouhou,2009). Regression equation for stretch% along weft isgiven in Table 5. R2 of the regression equation forstretch% along weft is 95.33% which signifies that95.33% change in the stretch% along weft can beexplained by the terms included in the equation.

Fabric recovery after stretch

Results of fabric recovery% along warp and weft of all thefabric samples are given in Table 3. Statistical analysis

Figure 5. Surface plots of stretch% along warp vs. threads per square cm, weave float, and elastane count (dtex).

Figure 6. Surface plots of stretch% along weft vs. threads per square cm, weave float, and elastane count (dtex).

The Journal of The Textile Institute 7

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15

given in Table 4 indicates that two factors elastane countand weave float are statistically significant for recovery%along warp because their p-value is less than 0.05, whilethe third factor, i.e. threads per square cm is notstatistically significant. However, one of the interactionsbetween factors, i.e. between elastane count (dtex) andthreads per square cm is statistically significant.

Surface plots of warp-way recovery vs. threads persquare cm, weave float, and elastane count (dtex) aregiven in Figure 7. It can be observed in Figure 7 (left)that recovery% along warp is best when threads persquare cm are minimum and the elastane count ismaximum. Elastane percentage is more in 78 dtex than44 dtex, so fabric produced from 78 dtex will have lessgrowth than a fabric produced from 44 dtex, hence therecovery% of 78 dtex yarn is more than that of 44 dtexyarn (Mourad, 2012). It can be concluded that recovery% along warp has direct relation with elastane count(dtex) and inverse relation with threads per square cm. Itcan also be noticed in Figure 7 (right) that longer theweave float and greater the elastane count (dtex) thengreater will be the warp-way recovery. The reason is due

to longer weave float, there will be less growth in fabric,because yarns will find less restrictions due to lessnumber of interlacements to return to their initialpositions, hence fabric will have more recovery.

Regression equation for recovery% along warp isgiven in Table 5. R2 of the regression equation forrecovery% along warp is 66.45% which signifies that66.45% change in the recovery% along warp can beexplained by the terms included in the equation.

Surface plots of recovery% along weft vs. threadsper square cm, weave float and elastane count (dtex) aregiven in Figure 8, where the trends for weft-wayrecovery are almost similar to those in the warp-wayrecovery. Regression equation for recovery% along weftis given in Table 5. R2 of the regression equation forrecovery% along weft is 83.27% which signifies that83.27% change in the recovery% along weft can beexplained by the terms included in the equation. Thehigher R2 value for weft-way equation as compared tothe warp-way equation suggests that the weft-way fabricrecovery is more predictable as compared to that in thewarp direction.

Figure 7. Surface plots of warp-way recovery vs. threads per square cm, weave float, and elastane count (dtex).

Figure 8. Surface plots of weft-way recovery vs. threads per square cm, weave float, and elastane count (dtex).

8 M. Maqsood et al.

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15

Conclusion

It was concluded that by increasing elastane count(dtex), both fabric stretch and recovery% along the warpincreased whereas in case of weft direction onlyrecovery% increased. Changing the elastane count (from44 to 78 dtex) did not have significant effect on thefabric contraction. Fabric contraction was moreinfluenced by the fabric thread density and float size ascompared to the elastane count. The effect of elastanecount was much more prominent in case of fabricrecovery as compared to other properties. The use ofhigher elastane count evidently resulted in fabric withbetter recovery properties. By increasing threads persquare cm, fabric contraction and stretch% along warpand weft decreased. However threads per square cmexhibited less significant effect on warp and weft-wayrecovery. Increase in the weave float resulted in increasein fabric contraction, fabric stretch along warp and weftand fabric warp and weft-way recovery. Suitability of theproduced fabric samples for compression garments wasalso tested and it was found that a fabric with greaterelastane count (dtex) and greater thread density generatesmore pressure (mmHg). However weave float size hasinverse relation with the pressure generation of theproduced samples. Statistical models were developed forfabric contraction, subgarment pressure, stretch, andrecovery properties of bi-stretch woven fabrics. Thesemodels may be helpful in designing bi-stretch wovenfabric in order to meet specific stretch and recoveryrequirements along with good subgarment pressure. Asan extension of this work, the authors are currentlyworking on the optimization of comfort and performanceof bi-stretch woven fabrics for compression therapy forpeople living in tropical weather conditions.

Disclosure statementNo potential conflict of interest was reported by the authors.

ReferencesAjayi, J. O., & Elder, H. M. (1997). Fabric friction, handle,

and compression. The Journal of The Textile Institute, 88,232–241. doi:10.1080/00405009708658547

Anand, S. C., Govarthanam, K. K., & Gazioglu, D. (2013a). Astudy of the modelling and characterisation of compressiongarments for hypertrophic scarring after burns. Part 1:

Modelling of compression garments. The Journal of TheTextile Institute, 104, 661–667. doi:10.1080/00405000.2012.753697

Anand, S. C., Govarthanam, K. K., & Gazioglu, D. (2013b). Astudy of the modelling and characterisation of compressiongarments for hypertrophic scarring after burns. Part 2:Characterisation of compression garments. The Journal ofThe Textile Institute, 104, 668–674. doi:10.1080/00405000.2012.739336

ASTM D6614 - 07. (2011). Standard test method for stretchproperties of textile fabrics CRE method. (n.d.). RetrievedFebruary 11, 2015, from http://www.astm.org/Standards/D6614.htm

El-Ghezal, S., Babay, A., Dhouib, S., & Cheikhrouhou, M.(2009). Study of the impact of elastane’s ratio and finishingprocess on the mechanical properties of stretch denim. TheJournal of The Textile Institute, 100, 245–253. doi:10.1080/00405000701757925

Hui, C. L., & Ng, S. F. (2001). Model to predict interfacialpressures in multilayer elastic fabric tubes. Textile ResearchJournal, 71, 683–687. doi:10.1177/004051750107100806

Kumar, B., Das, A., & Alagirusamy, R. (2013). An approach toexamine dynamic behavior of medical compressionbandage. The Journal of The Textile Institute, 104,521–529. doi:10.1080/00405000.2012.749573

McCalla Bennett, C. (1968). The effect of laundering on thestretch properties of selected cotton slack-mercerizedfabrics. Textile Research Journal, 38, 766–768.doi:10.1177/004051756803800713

Mourad, M. (2012). Physical and stretch properties of wovencotton fabrics containing different rates of spandex. Journalof American Science, 8, 567–572.

Ozdil, N. (2008). Stretch and bagging properties of denimfabrics containing different rates of elastane. Fibres &Textiles in Eastern Europe, 16, 63–67.

Rego, J. M., Verdu, P., Nieto, J., & Blanes, M. (2009).Comfort analysis of woven cotton/polyester fabricsmodified with a new elastic fiber, part 2: Detailed study ofmechanical, thermo-physiological and skin sensorialproperties. Textile Research Journal, 80, 206–215. doi:10.1177/0040517508099910

Sacevičienė, V., Masteikaitė, V., Klevaitytė, R., &Audzevičiūtė, I. (2011). Influence of the elastane fibre onthe woven fabric structural mobility. Journal of MaterialsScience, 17, 4–7.

Sawhney, A. P. S. (1974). The effect of fabric structure on theproperties of two-way stretch fabrics made from elasticcore-spun yarns of cotton and wool blend. Textile ResearchJournal, 44, 506–512. doi:10.1177/004051757404400707

Schuren, J., & Mohr, K. (2008). The efficacy of Laplace’sequation in calculating bandage pressure in venous legulcers. Wounds UK, 4, 38–47.

Su, C. I., Maa, M. C., & Yang, H. Y. (2004). Structure andperformance of elastic core-spun yarn. Textile ResearchJournal, 74, 607–610. doi:10.1177/004051750407400709

The Journal of The Textile Institute 9

Dow

nloa

ded

by [

182.

186.

134.

123]

at 1

9:55

09

Apr

il 20

15