chapter 3 materials and methods -...

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CHAPTER 3

MATERIALS AND METHODS

3.1 INTRODUCTION

This chapter discusses the materials and methods used in the study.

The following figure gives the overall methodology adopted in the present

study:

Figure 3.1: Flow chart for the methodology

Fibres

Viscose, modal, tencel and bamboo

Tested for properties like fibre tenacity, elongation, length and

fineness

Wicking by new method, data analysis by linear regression

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Yarns

Viscose yarns with various counts 16Ne(36.91tex), 20 Ne

(29.53tex), 24 Ne (24.6tex), 30(19.68tex), 34 Ne (17.37tex),

40 Ne (14.76tex), and 60 Ne (9.84tex)

Viscose yarns with different TPI levels

13.6, 17.53, 18.03, 19.07, 20.2, 30.97

Viscose polyester blended yarns

100% v, 20/80 p/v, 33/67p/v, 50/50p/v, 80/20p/v, 67/33p/v,

100% p

Tested for tenacity, elongation, RKM , imperfections, count , TPI, U% ,thin & thick places, neps and imperfections, yarn

hairiness, Yarn diameter

Count variation

30Ne (19.68tex) & 40Ne(14.76)

Tested for elongation, tenacity, imperfections single

yarn strength, TPI, U%, thin & thick places, neps and

imperfections & Yarn diameter

Twist variation

7.3,8.2,8.3 & 9.5T Pcm

Wicking,data analysis by linear regression

Wicking,data analysis by linear regression

Wicking and Wicking by varying tensions like 0.02g/tex, 0.026g/tex, 0.030g/tex, 0.036g/tex ,0.041g/tex,

0.047g/tex and 0.051g/tex Data analysis by linear regression




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3.2 MATERIALS

3.2.1 Selection of Manmade Cellulosic Fibres

In order to investigate the wicking behaviour of manmade cellulosic fibres -

viscose, modal, tencel, and bamboo fibers of 38mm length and 1.2 denier were

produced in a mill and used in the study.

Fabrics

Cotton fabric (woven) Silk fabric (commercial) Grey fabric (commercial)

Plain Twil Satin

Different sett 60, 72, and 84

Tested for PPI, EPI, warp count, weft count, warp cover factor, weft cover factor total Cover

factor & fabric weight Degumming

Dyeing with acid dyes

Exposure to sunlight 3 days, 6 days & 9 days

Scouring Bleaching

Desizing

Wicking, data analysis by linear

regression

Wicking

Tested for fabric weight, thickness, porosity, tensile strength, elongation, drape coefficient, stiffness, crease recovery, flexural rigidity

Different media Distilled water, acid perspiration,

alkaline pH, Water temperature at 800C

Tested for ends/inch, picks /inch, warp count,

weft count, weight, thickness, tensile strength

and elongation, drape coefficient, flexural

rigidity, stiffness and k/s values

Wicking, data analysis by linear regression

Data analysis by linear regression

Mulberry Tasar

Mercerization




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3.2.2 Selection of Yarns with Various Linear Densities

Viscose staple yarns with various linear densities like 16Ne(36.91tex),

20Ne (29.53tex), 24 Ne (24.60tex), 30 Ne (19.68tex), 34 Ne (17.37 tex), 40 Ne

(14.76 tex) and 60 Ne (9.84tex) were produced in a mill and used in the study.

The details of the viscose staple yarns are given below:

Table 3.1: Details of the viscose staple yarns with various densities

S.No. Yarns Spinning system

Linear Density (Ne/Tex)

1 100% Viscose Ring Spinning 16/36.91 2 100% Viscose “ 20/29.53 3 100% Viscose “ 24/24.60 4 100% Viscose “ 30/19.68 5 100% Viscose “ 34/17.37 6 100% Viscose “ 40/14.76 7 100% Viscose “ 60/9.84

3.2.3 Selection of yarns with different twist levels

A series of viscose staple yarns with twist factors of 24.3, 31.3, 32.2, 34.1,

36.2 and 55.4 tex0.5tpcm was prepared. Details of the viscose staple yarns are

given below:

Table 3.2: Details of viscose staple yarns with different TPcm levels

S.No Fibre content

Spinning system Twist/cm Twist Factor (K)

TPcm (Tex)0.5 Tensions (g/tex)

1. 100%Viscose Ring Spinning 5.4 24.3

0.020, 0.026, 0.030, 0.036, 0.041, 0.046

and 0.051 2. 100%Viscose “ 7 31.3 “ 3. 100%Viscose “ 7.2 32.2 “ 4. 100%Viscose “ 7.6 34.1 “ 5. 100%Viscose “ 8.1 36.2 “ 6. 100%Viscose “ 12.4 55.4 “




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3.2.4 Selection of Fibres

Polyester and viscose staple fibres of 38mm length and 1.2 denier were

used for the study.

3.2.5 Selection of Fabric Samples

Different types of fabrics such as commercially available cotton grey,

mulberry and tasar silk fabric and woven fabrics with different pick densities were

used in this study. Cotton woven fabrics with plain, twill and satin structures of

40s count in the warp and 2/80s count in the weft and the pick density variations of

60,72 and 84 were chosen for the construction. Grey cotton material were used to

investigate the effect of wicking behaviour and the fabric properties were tested

and analyzed. Different mediums like distilled water, acid perspiration, alkaline

pH and water temperature at 80oC were used after applying finishing treatments

like scouring, bleaching and mercerization on them and wicking was studied along

the warp, weft and bias directions. Commercially purchased mulberry and tasar

silk fabrics were degummed, dyed and exposed to sunlight for 3 days, 6 days and

9 days respectively and then the fabric properties and wicking behaviour were

investigated.




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Table 3.3: Geometrical properties of woven cotton fabrics

Sample Code FFF

Ends/ cm

Picks/ cm

Warp count

Weft count

Warp cover factor

Weft cover factor

Total factor

Fabric weight (g/m2)

Fabric thickness

(mm)

Porosity %

P60 0.52 35.43 22.83 39.8 43.8 14.27 8.76 18.56 53.49 0.25 86

P72 0.61 35.83 29.92 41 43 14.21 11.59 19.92 62.08 0.28 85

P84 0.64 35.83 32.28 40.2 41.2 14.35 12.78 20.58 65.67 0.3 85

T60 0.33 35.83 23.23 38.6 41.2 14.65 9.19 19.03 60.65 0.3 87

T72 0.39 36.22 28.74 38.4 42 14.85 11.26 20.14 67.11 0.32 86

T84 0.41 36.61 34.25 40.2 42.4 14.67 13.36 21.03 69.02 0.34 86

S60 0.37 35.83 25.20 41.4 41.8 14.14 9.90 19.04 64.71 0.36 88

S72 0.43 36.22 30.31 39.4 47.2 14.66 11.21 20 69.02 0.38 87

S84 0.45 36.22 32.28 41.8 40.8 14.23 12.84 20.54 71.77 0.4 87

FFF = Fabric Firmness Factor




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Table 3.4: Details of grey fabric

S.No Particulars Grey fabric 1. 2. 3. 4. 5. 6. 7. 8.

Ends/cm Picks/cm

Warp count Ne(Tex) Weft count Ne(Tex) Warp cover factor Weft cover factor Total cover factor

Fabric weight

39.76 28.35

50(11.80) 41(14.39)

14.28 11.25 19.80

110g/m2

Chemicals used for scouring

Sodium hydroxide, sodium silicate, wetting agent

Chemicals used for bleaching

Hydrogen peroxide, sodium hydroxide, sodium silicate and soda ash

Chemicals used for mercerization

Caustic soda and acetic acid

Chemicals used for acid perspiration solution

Lactic acid, disodium hydrogen orthophosphate and histidine

monohydrochloride

Chemicals used for alkaline ph solution

Sodium hydroxide




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Table 3.5: Details of mulberry and tasar silk fabrics

Properties Mulberry Tasar Weight (g/m2) 33.69 31.09

Thickness (mm) 0.081 0.081 Ends /cm 49.1 40 Picks /cm 43.2 19

Warp count (dtex) 35.32 41.32 Weft count (dtex) 35.32 47.32

Chemicals used for Silk Fabric Degumming

Soap and soda ash

Chemicals used for dyeing

Turquoise blue acid dyes, Glauber’s salt and acetic acid

3.3 METHODS

3.3.1 Yarn Production

Process Parameters for Spinning

Carding Feed roller speed 0.5rpm Cylinder speed 900 rpm Licker - in 600 rpm Doffer 4.0 rpm

Drawing

Front roller speed 50 rpm Back roller 5 rpm




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Roving No of spindles 4 Twist 30 tpm Roving hank 1.2Ne Feed hank 0.14Ne

Spinning No of spindles 6 Spindle speed 13000rpm

Twist 30/40 tpm TPI 18.64, 20.81, 21.5, 24.03

Roving count 1.18 Ne Twist multiplier 3.4, 3.8 (TM=TPI /COUNT) Twist direction Z

Break draft 1.8 Yarn length 5000m

Yarn contraction 2.37

Figure 3.2: Flow chart for producing polyester viscose blended yarns

Fibers (Polyester and Viscose)

Computerized Carding Machine

Computerized Miniature Draw Frame

Computerized Simplex Roving Machine

Computerized Ring Spinning Machine

Cone Winding Machine




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Polyester and viscose fibres were processed through carding and draw

frame packages. Drawn sliver was passed through simplex frame and spun into

yarns differing in blends of 19.68 tex and 14.76tex with TPcm 7.5, 8.3, 8.6 and 9.6

in computerized ring spinning machine. Polyester and viscose fibres were blended

consisting of, 100% polyester, 80/20 P/V, 67/33 P/V, 50/50 P/V, 20/80 P/V, 33/67

P/V and 100% viscose. A total of twenty eight yarns were produced which are

shown in Table 3.6.

Table 3.6: Details of the polyester viscose blended yarns with various

counts and twist levels

S.No Fibre content Spinning system Linear Density

(Ne /Tex) Twist /cm

1. 100%viscose Ring Spinning 30/19.68 7.5, 8.3

40/14.76 8.6, 9.6

2.. 20/80 polyester viscose “ 30/19.68 7.5, 8.3

40/14.76 8.6,9.6

3. 33/67 polyester viscose “ 30/19.68 7.5, 8.3

40/14.76 8.6, 9.6


40/14.76 8.6, 9.6


40/14.76 8.6, 9.6


40/14.76 8.6, 9.6

7. 100% Polyester “ 30/19.68 7.5, 8.3

40/14.76 8.6, 9.6




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3.3.2 Fabric Production Handloom Weaving

Weaving is done by intersecting the longitudinal threads, the warp, i.e. "that

which is thrown across", with the transverse threads, the weft, i.e. "that which is

woven". The major components of the loom are the warp beam, heddles, harnesses

or shafts shuttle, reed and takeup roll. In the loom, yarn processing includes

shedding, picking, battening and taking-up operations which are the principal

motions.The count of warp yarn selected was 2/80s and 40s count for the weft.

Cotton fabric with plain(1/1), twill(2/1) and satin structures(4/1) were woven by

varying the setts namely 60,72 and 84.

3.4 TREATMENT APPLIED FOR FABRICS

Desizing

The woven cotton grey plain, twill and satin fabrics with various pick

densities were desized with 2% of dilute hydrochloric acid for a period of one

hour at a temperature of 50-600C. Then, the fabric is taken out , rinsed

thoroughly in cold water until the water runs.

The commercially purchased cotton grey fabric was scoured, bleached and

mercerized using the procedure given below:

Scouring

Scouring was carried out by adding 7% of sodium hydroxide , 1% of

wetting agent and 2% of sodium silicate at 60-80c for 1 hour. Then the fabric

was taken out and rinsed thoroughly.




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Bleaching

Bleaching was carried out by using 7% hydrogen peroxide, 2%sodium

silicate, 1% soda ash and 0.6%sodium hydroxide at 85-900 c for 1 hour. Then the

fabric was taken out and rinsed thoroughly.

Mercerization

Mercerization was carried out by using 20% of caustic soda at 60-800 C for

half an hour. Acetic acid was added in both hot and cold water while rinsing in

order to remove the traces of alkali present in the fabric. Finally litmus paper was

used to check the acidity or alkalinity of the solution and was found neutral.

Table 3.7: Details of scoured, bleached and mercerized samples

S.No Samples Treatments Medium Direction

1. STWE Scouring water temperature at 800c weft direction

2. STW “ “ warp direction

3. STB “ “ bias direction

4. SDWWE “ distilled water weft direction

5. SDWW “ “ warp direction

6. SDWB “ “ bias direction

7. SAPWE “ acid perspiration weft direction

8. SAPW “ “ warp direction

9. SAPB “ “ bias direction

10. SAWE “ alkaline ph weft direction

11. SAW “ “ warp direction

12. SAB “ “ bias direction




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S.No Samples Treatments Medium Direction

13. BTWE Bleaching water temperature at 800c weft direction

14. BTW “ “ warp direction

15. BTB “ “ bias direction

16. BDWWE “ distilled water weft direction

17 BDWW “ “ warp direction

18. BDWB “ “ bias direction

19. BAPWE “ acid perspiration weft direction

20. BAPW “ “ warp direction

21. BAPB “ “ bias direction

22. BAWE “ alkaline ph weft direction

23. BAW “ “ warp direction

24. BAB “ “ bias direction

25. MTWE Mercerization water temperature at 800c weft direction

26. MTW “ “ warp direction

27. MTB “ “ bias direction

28. MDWWE “ distilled water weft direction

29 MDWW “ “ warp direction

30. MDWB “ “ bias direction

31. MAPWE “ acid perspiration weft direction

32. MAPW “ “ warp direction

33. MAPB “ “ bias direction

34. MAWE “ alkaline ph weft direction

35. MAW “ “ warp direction

36 MAB “ “ bias direction




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Degumming

The commercially purchased mulberry and tasar silk fabrics were

degummed using the following procedure and the percentage of weight loss was

calculated and then dyed with acid dyes.

MULBERRY TASAR Original weight 360 gms 440 gms Soap oil 5% 5% pH 6.5 – 7 6.5 – 7 Time 30 mins 30 mins Temperature 90˚C 90˚C M:L 1:50 1:50 Fabric weight after degumming 290 gms 410 gms Percentage of weight loss 19.44% 6.81%

Dyeing

The degummed mulberry and tasar silk fabrics were dyed with turquoise

blue acid dyes with 5% shade. . The dye bath was prepared by dissolving the dye

in warm water and the fabrics were added to dye bath and continuously agitated

for the uniform penetration of the dye throughout the fabric and the temperature

was raised to 800C for 40 minutes. Then acetic acid was added to the dye bath and

worked for another 15minutes. Finally the fabrics were rinsed thoroughly in hot

and cold water and dried under shade

Exposure to sunlight

The dyed mulberry and tasar silk fabrics were fixed on a cardboard and

exposed to sunlight during the month of March from 10 am to 5pm. The fabrics

were laid flat and exposed for 3days, 6days and 9days respectively and then the

fabric properties were studied.




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3.5 TESTING OF FIBRES, YARNS AND FABRICS 3.5.1 Fibre Testing .

The fibre properties of man made cellulosic fibres like bamboo, tencel,

modal and viscose and polyester fibres were tested. All the tests were carried out

in standard atmospheric condition of R.H.65%+/- 2% and temperature 210 C +/- 1

Degree C. Fibres were conditioned for 24hrs in above atmospheric conditions

before testing.

Measurement of Fibre Length

Fibre length is the one of the most important dimension to evaluate the

quality of the raw material. Oil plate is used to arrange the fibers. Liquid paraffin

oil was used to remove the crimp from the fiber. Then arrange 200 fibers orderly

in a parallel manner, and then the length was measured using 0.5 mm accuracy

measuring scale. An average of 15 readings were taken at random and the mean

value was calculated and recorded .

Measurement of Fibre strength and elongation

Vibroscope & Vibrodyn was used to calculate the strength and elongation

of fibres using BISFA 2004 and ASTM D-3822-07 standards .Measuring range of

force 0-1000 cN, measuring range of elongation max. 1000% at 10 mm gauge

length, gauge length 5-50mm, tension weight 100 mg and testing speed of 0.5 to

300 mm/min. An average of 30 readings were taken at random and the mean value

was calculated.

Measurement of Fibre fineness

Vibroscope 400 is an automatic instrument for the determination of the titer

(dtex, denier) of single fibers. This instrument meets international standards




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BISFA 2004 and ASTM D-3822-07. An average of 30 readings were taken at

random and the mean value was calculated.

Table 3.8: Fibre testing and standards

Nature of the Test Testing Standards Instrument Fibre length BISFA 1998 Oil Plate Method

Fibre Fineness BISFA 2004 &

ASTM D-3822-07 Vibroscope 400

Fibre strength and Elongation

BISFA 2004 & ASTM D-3822-07

Vibroscope &Vibrodyn

3.5.2 Yarn Testing

The yarn properties like count, twist, single yarn strength and elongation,

RKM, imperfections, count, hairiness, and yarn diameter were tested. All the tests

were carried out in standard atmospheric condition of R.H.65%+/- 2% and

temperature 210 C +/- 1 Degree C. Yarns were conditioned for 24hrs in above

atmospheric conditions before testing.

Table 3.9: Yarn testing and standards

Nature of the Test Testing Standards Instrument

Single yarn strength gms , elongation and RKM

Uster standard method Uster Tensorapid 3

Yarn Hairiness Uster standard method

Uster Hairiness Index Tester -4

Twist per inch ASTM D 1422 -99 Microprocessor Twist Tester

Lea count ASTM D 1578 – 93 ASTM D 1907 -07 Statex CSP System

U%, Thin places -50%perkm,Thickplaces+50%perkm Nep+200%perkm, Yarn Imperfections Per km

ASTM D 1425 - 96 Uster Tester 4

Yarn Diameter Image Analyser




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Measurements of Twist

In the microprocessor twist tester, the twisting and untwisting jaws are

driven by a fractional H.P single phase motor. A speed control device is provided

on the left hand side of instrument by which the motor speed can be varied while

conducting the twist tests. The gauge length of the specimen can be selected upto a

minimum of 25cm(10inches ) by moving the non rotating jaw assembly. A scale is

fixed on the instrument to read the actual gauge length. A direction reverse switch

and two counters are fixed on the instrument for testing the twist of the yarns .An

average of 15 readings were taken at random and the mean was calculated. . Measurements of Single Yarn Strength & Elongation

Uster Tensorapid 3 was used to determine the strength and elongation .This

instrument is works on the principle of CRE (Constant Rate of Elongation). It also

gives estimated RKM value for yarn. Strength and Elongation are displayed

following each test. This can be expressed by the “Length of yarn in km” at which

yarn will break of its own weight”. This is equivalent to breaking load in g/tex.

RKM is the short expression for “Ressikilometer” – “Breaking-kilometer”.An

average of 100 tests were carried out at random and the mean value was

calculated. Measurements of yarn count

Yarn count and count CV% were measured on Statex yarn count system

which is a combination of electronic balance and computer, Using this system,

readings were taken from the yarn samples and the mean value was calculated. Measurements of U%, thin places, thick places and imperfections

Uster Eveness tester 4 was used to determine the U%. Uster evenness tester

consists of a device to apply uniform tension in yarn during testing and suitable




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counter for recording the number to thin places, thick places and number of neps

present in the yarn.

Measurements of Yarn Diameter

Diameter was assessed using image analysis technique. For each twist step,

a yarn photo is captured and examined by a Motic microscope with 40x

magnification. For analysis of the yarn images, "Image-Pro-Plus 2.0" software was

used. The image analysis was performed using the sequence: process, image,

acquise, segmentation, processing and measurement. An average of 20 readings

was taken at random and the mean was calculated.

Measurements of Hairiness Index

The yarn hairiness was measured using Uster Tester-4 using the uster

standard method . Hairiness index has been defined as the total length of

protruding fibres with reference to the sensing length of 1cm. It provides the

signals and helps in the interpretation of results.

Yarn Quality Index

In order to compare the relative performance of the six yarns, the yarn

quality index was followed.

Tenacity, elongation and evenness are combined into one integrated index

called yarn quality index (YQI)). YQI is defined as follows:

Tenacity X Elongation

YQI = ------------------------------- Evenness

This formula has been suggested by Barella (1975).




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Determination of Twist Factor

Twist factor was calculated using the formula turns per cm divided by the

square root of tex.

Tex Twist factor K = Turns per cm/ tex

Determination of Packing Factor

Packing factor was calculated from yarn diameter considering standard

density of viscose (1.5gcm -3).

Packing Factor = Yarn density in g/cm3 /Fibre density/g/cm3

Yarn density =(Yarn linear density in tex x 1.2727x10 -5) / (Yarn diameter in

cm)2g/cc.

3.5.3 Fabric Testing

The cotton woven fabric with different structures and sett were tested for

properties like weight, thickness, tensile strength and elongation, crease recovery,

bending length, flexural rigidity, drape coefficient, fabric firmness factor and

porosity whereas the dyed and exposed mulberry and tasar silk fabrics were tested

for properties like weight, thickness, tensile strength and elongation, bending

length, flexural rigidity, drape coefficient and k/s values. The commercially

purchased cotton grey fabric was tested for EPI, PPI, warp cover factor, weft cover

factor, total cover factor and fabric weight. All the tests were carried out in

standard atmospheric condition of R.H.65%+/- 2% and temperature 270 C +/- 2

Degree C. Fabrics were conditioned for 24hrs in above atmospheric conditions

before testing.




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Table 3.10: Fabric testing and standards

Nature of the test Testing Standards Instrument Thickness (mm) IS: 7702 – 2006 Mag thickness tester

Crease recovery (Angle) IS 4681 Mag crease recovery tester

Tensile strength (Kgs) and Elongation (%) ASTM D 1776 Mag electronic tensile strength

tester

Bending length (cm) IS 6490, ASTM D 1338

Mag stiffness tester

Fabric weight (g/m2) ASTM 3776-96 Paramount quadrant balance Drape coefficient (%) IS 8357 Mag drapemeter

Measurement of Fabric weight

A sample size of 20cm x12.5 cm was cut using the template and the weight

was calculated using the quadrant balance. Ten samples were cut from the same

material by using the template and readings were taken in grams per square meter

and the mean fabric weight was calculated and recorded.

Measurement of Fabric thickness

Mag thickness tester is a hand operated instrument to determine the

thickness of the fabric; each sample was placed in between the pressure foot and

anvil. The thickness of the fabric was indicated in the dial gauge, in the terms of

millimeter. The thickness was measured at ten different places of each sample at

random and the mean value was calculated and recorded.

Measurement of Tensile Strength and Elongation

The principle used in the tester is CRE (Constant Rate of Elongation). Five

samples each were cut from warp and weft directions. The sample size is 12” x 2”.

Each sample was clamped between the jaws and care was taken to see that the




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sample were perpendicular to the load. The load was applied and the reading was

recorded in kilograms and elongation in millimeters was noted as soon as the

sample was broken. Five such readings were taken and the mean strength and

elongation was calculated.

Measurement of Fabric drape

Fabric samples and ammonia paper of 12.5cm diameter was cut using the

template; and weighed using an electronic balance. Each sample was placed on the

circular disc and ammonia paper underneath the disc and the drape meter is

operated. Image of the draped sample, can be obtained on the ammonium paper

.This image was traced and cut along the traced outline. It was then weighed using

electronic balance. The drape co-efficient was calculated for each sample using the

following formula.

Drape co-efficient = W2-W1 100

Where W2 = the weight of the drape pattern

W1 = the weight per unit area of the paper

Measurement of Fabric Stiffness

The principle used in the tester is cantilever principle. The samples were cut

according to the template size in both warp and weft randomly. The sample was

placed lengthwise on the platform and the scale is placed over the specimen such

that the zero of the scale coincides with the datum mark on the body of the

instrument. Now the scale was pushed forward gently and till the tip of the fabric

coincides with the index line on the side of the platform. Ten readings were taken

for each sample and the mean values were calculated and recorded. From these

values, flexural rigidity was computed by substituting bending length and weight

in grams per centimeter square in the formula




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Flexural rigidity (mg.cm) = WC3

where

W = fabric mass in g/cm2

C = bending length in cm Measurement of Crease recovery

This instrument consists of a circular dial which carries the clamp for

holding the sample. Directly under the center of the dial is a knife edge and an

index line for measuring the recovery angle. The scale of the instrument is

engraved .The dimension of the specimen is 2 inch by 1inch. Warp and weft

crease recovery was reported separately to the nearest degree. The mean value of

ten readings in each direction was calculated and recorded.

Determination of Porosity %

Porosity is defined as the fraction of void space in a porous medium:

Porosity % = 1- ρa / ρb Where ρa is the fabric density (g/cm3) and ρb is the fibre density (g/cm3).

Fabric density is calculated by dividing the fabric weight per unit area by fabric

thickness. This equation includes the inter –fibre porosity as well as the inter-yarn

porosity of the fabric. The porosity of the plain twill and satin structures with

various pick densities were captured by a microscope (CT Belgium) under 40

magnification.

Fabric Firmness Factor (FFF)

This was calculated using the formula given by Milasius (2000):

21

21

21 T/T3/21T/T3/2

2T/T3/21

1

2average SS

T'P

112




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Where T1, T2 and Taverage are, respectively, the warp count, weft count and

average count in Tex. P’ is the Milasius weave factor and is the fibre density S1

& S2 are the ends and picks per decimeter.

Crossing Over Firmness Factor (CFF) This was defined by Morino et al., (2005) using the following formula:

CFF= Ne /Ni

Where

Ne = number of crossing over lines in the complete repeat

Ni = number of interlacing points in the complete repeat

Floating Yarn Factor (FYF)

The formula for calculating FYF is given below:

FYF= ((Type I-IX -1) x En) /Ni

Where En = existing number of Type I-IX in the complete repeat.

Color Measurement

The samples are measured using premier color scan spectrophotometer

5100in Day 65 daylight and 10 degree standard observer. The output of the

spectrophotometer is reflectance data from 400nm to 700nm.

The color yields of the dyed and sunlight exposed samples were evaluated

by the Kubelka –Munk equation

K/S = (1-R) ²/ 2R

Where R – reflectance at maximum absorption wavelength (nm)

S – scattering coefficient

K - absorption coefficient




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The colour differences are expressed as ΔE which is calculated by the

following equation

E = √ (ΔL*)² +(Δa*)²+ (Δb*)² ……………………(3.1)

Where ΔE is the CIELAB color difference between batch and standard.

Here ΔL*, Δa* and Δb* and ΔE* are in commensurate units. ΔL denotes the

difference between lightness (where L*= 100) and darkness (where L* = 0). Δa* is

the difference between green ( -a*) and red ( + a*) and Δb the difference between

yellow (+b*) and blue ( - b*).

The commercially purchased cotton grey fabric was tested for the following

parameters.

EPI (Ends per cm)

In woven fabric the warp yarns are commonly referred to as ‘end’ and the

number of warp threads per inch width of cloth stated as ‘ends per inch’.

One inch counting class- This is the most commonly used method. The

counting glass is placed on the fabric and the number of threads per inch is

counted through this small microscope. The threads per inch were counted at

different places and the mean value was calculated.

PPI (Picks per cm)

In woven fabric the weft yarn are commonly referred to as “picks” and the

number of weft threads per inch length of cloth stated as “picks per inch”.The ends

per inch and picks per inch were measured by an ordinary counting glass

according to ASTM-D 3775-03. Ten readings were taken and average value was

calculated.




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Warp count and Weft count

The warp and weft count were measured by using the Beesley balance as

per ASTM – D 1059. Ten readings were taken and average value is noted for the

study.

Cover factor

The cloth cover factor was calculated using the following formula.

Cloth cover factor Kc = K1+K2 28KK 21

Where K1 = warp cover factor

K2 = weft cover factor

To determine the cover factor, ends/inch and picks/inch of the fabrics were

counted by pick glass. ASTM –D 1059 -01 were used to measure the warp and

weft count. This test method determines the count of all types of fabrics in which

the yarns are intact and can be removed in measurable length. The counts of the

warp and weft were calculated from the mass and the measured length of the yarn

in terms of “mass per unit length”.

. 3.6 STATISTICAL ANALYSIS 3.6.1 Regression Analysis

Regression analysis involves identifying the relationship between a

dependent variable and one or more independent variables. A model of the

relationship is hypothesized, and estimates of the parameter values are used to

develop an estimated regression equation. Various tests are then employed to

determine if the model is satisfactory (www.britannica.com).


http://www.britannica.com).



86

3.6.2 Correlation Coefficient

Correlation analysis is used to determine whether the values of two

variables are associated. The two variables should be random samples, and should

have a normal distribution (possibly after transformation).A correlation coefficient

is a numerical, descriptive measure of the strength of the linear relationship

between two variables. Values for the correlation coefficient range between -1 and

+1, with a correlation coefficient of +1 indicating that the two variables have a

perfect, upward-sloping (+) linear relationship and a correlation coefficient of -1

showing that the two variables are perfectly related in a downward-sloping (-)

linear sense. A correlation coefficient of 0 demonstrates that the variables have no

relationship, and are independent. A correlation coefficient is determined through

statistical analysis of sample data as it is fitted to a modeled linear equation

(www.investorglossary.com).


http://www.investorglossary.com).



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