garment waste recycled cotton/polyester thermal and...

Research ArticleGarment Waste Recycled CottonPolyester Thermaland Acoustic Properties of Air-Laid Nonwovens

S Sakthivel1 Bahiru Melese1 Ashenafi Edae1 Fasika Abedom 2 Seblework Mekonnen2

and Eshetu Solomon2

1Department of Garment Technology FTVET Institute Addis Ababa 190310 Ethiopia2Department of Textile Technology Textile Apparel and Fashion Technology Division FTVET Institute Addis Ababa 190310Ethiopia

Correspondence should be addressed to Fasika Abedom fasikaabedom06gmailcom

Received 18 June 2020 Accepted 14 August 2020 Published 27 September 2020

Academic Editor Dimitrios E Manolakos

Copyright copy 2020 S Sakthivel et al is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

is research paper reports a study on thermal and sound insulation samples developed from garment waste recycled cottonpolyester fiber (recycled cottonPET) for construction industry applications In this research work the piece of clothing wasterecycled cotton and polyester fiber is a potential source of raw material for thermal and sound insulation applications but itsquantities are limited To overcome the above problems apparel waste recycled cotton fiber was mixed with recycledPET fiber in5050 proportions in the form of two-layer nonwoven mats with chemical bonding methods e samples such as cotton (colorand white) polyester (color and white) and cottonndashpolyester blend (color and white) were prepared All the samples were testedfor thermal insulation acoustic moisture absorption and fiber properties as per the ASTM Standard Also the behavior of the sixrecycled cottonpolyester nonwoven samples under high humidity conditions was evaluated e sound absorption coefficientswere measured according to ASTM E 1050 by an impedance tube method the acoustics absorption coefficients over six fre-quencies of 125 250 500 1000 2000 and 4000Hz were calculated e result revealed that recycledPETcotton garment wastenonwoven mats were absorbing the sound resistance of more than 70 and the recycled nonwoven mats provided the bestinsulation acoustic moisture absorption and fiber properties e recycled pieces of clothing waste cottonpolyester nonwovenmats have adequate moisture resistance at high humidity conditions without affecting the insulation and acoustic properties

1 Introduction

e concern over the environment induced a large numberof companies to start developing the manufacturing processusing alternative materials for their products and seekingnew markets With the significant production of waste fi-brous materials different companies are looking for ap-plications wherein waste materials may represent an added-value material [1ndash3] ermal insulation plays an importantrole in contributing to the energy savings in the building byheat gains and losses through the building envelope [4] Astudy reported that effective building insulation alone willsave over one hundred times the impacts of the carbonfootprint from material usage and disposal irrespective ofthe materials used [5] Knitted waste can be converted into

short fibers by the application of mechanical processes Aseries of trials have been undertaken in the course of aresearch project aimed at more or less complete reuse offibers from end-of-life textiles First of all knitted waste iscrushed with a shredder [1] e use of recycled polyesternonwovens has many advantages compared to conventionalsound absorbers including reduced product cost goodhandling and environmental protection e sound ab-sorption coefficient of the recycled polyester nonwovens wasdetermined by a two-microphone impedance measurementtube the determination of the noise absorption coefficient isnothing more than the absorption energy rate of the materialagainst the incidence energy ey have determined therelationship between the acoustic absorption values mea-sured and the nonwoven parameters including fiber

HindawiAdvances in Materials Science and EngineeringVolume 2020 Article ID 8304525 8 pageshttpsdoiorg10115520208304525

properties and web properties [6] A study was conducted onthe sound absorbency of a novel knitted spacer fabric thatcan be applied to automotive interior parts and has thepotential for greater sound absorbency than conventionalplain knitted fabrics [7 8] Recently noise absorbent textilematerials especially nonwoven structures or recycled ma-terials have been widely used because of the low productioncosts and they are being aesthetically appealing [9ndash11]Recycled polyester (RPET) fiber is derived from the post-consumer waste of plastic bottles which are a potentialsource of raw material for reducing environmental pollution[12] A study has been reported on the development ofinsulation materials from recycling cotton fiber with com-parable properties as that of conventional materials [13] Inanother recent study the authors highlighted the quantityissues of alterative recycled polyester materials available inthe market to meet the demand for the building sectoralthough recycled cotton materials are very good insulatorse absorption of sound mainly results from the dissipationof acoustic energy due to viscosity and heat conductivity ofthe medium Differences in pore structure due to differentfiber orientation and random arrangement of fibers producesamples with small pores and a higher amount of fiber-to-fiber contact points which ends in better sound absorptionproperties [14] In this study chemically bonded nonwovenswere manufactured from reclaimed fiber and tested for thesound absorption performance e sound absorptioninfluencing factors such as thickness density air perme-ability porosity and thermal conductivity were measuredaccording to the ASTM Standard and the purpose of con-struction industry applications

2 Experimental Work

21 Materials e raw materials used in this research areldquocut and sewrdquo knitwear production waste materials ewaste materials were collected from knitwear garment in-dustries then segregated depending on their colors andprepared for recycling to process in waste recycling ma-chines ese wastes are then fed into the reused fabricopener machine to obtain recycled fibers e recycled fiberis then converted into a web structure with different densityby using the mechanical carding process in the cardingmachine to form air-laid webs and the binder used here ispolyvinyl acetate (PVA) as shown in Figure 1 e bindersaturates on the surface layers and does not penetrate far inthe structure which is normally quite thick

e spray adhesive bonding is an exact measure of thenumber of binders applied uniform binder distribution and asoft fabric handlee adhesive add-on percentage is taken careof to maintain at 20 Precaution is taken to avoid the excessiveor lesser flow of adhesive through the sprayer By the calendarroller pressure the fibrous layer is converted into nonwovenfabric [15] e produced recycled cottonpolyester samplessuch as cotton (color and white) polyester (color and white)and cottonndashpolyester blend (color andwhite)WCCCWPCPWCP andCCP sampleswere preparedepreferred samplesof proportions with 6ndash8mm thick 80mm wide and 200mmlong were developed to measure the sound absorption

coefficient Figure 2 shows the prepared samples of color (a) andwhite adhesive-bonded (b) recycled nonwovens

e physical properties of nonwoven are fabric thick-ness density porosity air permeability and thermal con-ductivity were tested according to the ASTM standard andphysical properties were tested to measure the influence ofthe acoustic absorption coefficient of recycled nonwovens

22 Methods of Testing

221 ickness e thickness tester is a specializedequipment to determine the thickness of nonwoven fabricsthe mean value of all the readings of thickness that weredetermined to the nearest 001m is calculated and the resultis the average thickness of the sample under test e fabricthickness was determined by ASTM D 5729 standardmethod

222 Density A study by Koizumi et al [16] showed theincrease of sound absorption value in the middle and higherfrequency as the density of the sample increased especimen with 12 cm diameter and 80 cm2 areas were cut outrandomly and weighed Average of 20 observations wastaken for each sample and expressed in kgm2 e densitywas calculated by using the following relationship

density Wt

kgm3 (1)

where w is the weight of the sample per unit area deter-mined following the standard method ASTM D 3776mmass and V volume e SI unit of density is kgm3Water of 4degC is the reference ρ 1000 kgm3 1 kgdm3 1 kgl or 1 gcm3 1 gml

223 Porosity e porosity of a porous material is definedas the ratio of the volume of the voids in the material to itstotal volume is stated by Allard et al [17] e followingequation defines porosity as

porosity (H) Va

Vm

(2)

where Va volume of the air in the voids and Vm totalvolume of the sample of the acoustical material being testede porosity was found out with ASTM B 809

Figure 1 Schematic representation of adhesive bonding

2 Advances in Materials Science and Engineering

224 Air Permeability e rate of airflow passing per-pendicularly through a known area of fabric is adjusted toobtain a prescribed air pressure differential between the twofabric surfaces and it is generally expressed in terms of cm3scm2 calculated at operating conditions From this rate ofairflow the air permeability of the fabric is determinedunder ASTM Test Method D 737

225 ermal Conductivity ermal conductivity coeffi-cient of specimens was measured using Leersquos disk methodprinciple (Saleem [18])

Q VI

aATA + asTA + TB + ABTB + acTc

K Qts

TB minus TA

1113888 1113889TA + 2TA

r

tA + tS

41113874 1113875 +

tSTB

2r1113874 1113875

(3)

where heat transfer is the measurement of the thermalenergy transferred when an object having a defined specificheat and mass undergoes a defined temperature changeHeat transfer (mass) (specific heat) (temperature change)QmcΔT where Q heat content in joules and mmass

e thermal conductivity of samples was then calculatedtheoretically by using theMaxwell model as illustrated abovewhere comparisons between theoretical and experimentalresults were accomplished e thermal conductivity wasdetermined following ASTM D 6343

226 SEM Analysis Test Morphological analysis was per-formed as per the ASTM D 256 Standard using a JEOL SEMinstrument on cryogenically fractured surfaces of nonwo-ven samples e developed nonwovensrsquo fractured surfacesafter tensile testing are examined using a scanning electronmicroscope (SEM) JEOL JSM-6480LV as shown in Figure 3

227 Measurement of Sound Absorption Coefficient enormal incident sound absorption coefficients (α) weremeasured according to the ASTM E 1050-10 Standard testmethod by using an impedance tube as shown in Figure 4

which was kindly provided by Automotive Research andTesting Center (ARTC Taiwan) When a sound wave is anincident on a material it can be absorbed reflected andtransmitted by the material all three phenomena arepossible depending upon the types of materials Ab-sorbing the incident sound wave is an effective way tocontrol the noise

e frequency ranges used for the measurement were50ndash4000Hz e frequency range was divided into threedifferent classes low (50ndash1000Hz) medium(1000ndash2000Hz) and high (2000ndash4000Hz) ranges Tenreadings were taken randomly from each sample for eval-uating acoustic properties e sound resistance or insu-lation by the recycled nonwoven fabric samples can becalculated by the following derivation by Teli [19] andSengupta [20]

SR dBwos minus dBws

dBwostimes 100 (4)

where SR is the sound reduction dBwos is the sound levelwithout sample and dBws is the sound level with sample

3 Results and Discussion

31 SoundAbsorption Property One of the objectives was toobtain superior sound absorption property in the samples inaddition to the thermal insulation property e garmentwaste recycled cottonpolyester samples such as cotton(color and white) polyester (color and white) and cot-tonndashpolyester blend (color and white) were prepared ephysical properties of the recycled nonwovens have thefollowing results as shown in Table 1

All developed recycled nonwoven samples showed bettersound absorption properties in the overall frequency range(50ndash4000Hz) Sound absorption coefficients (αc) of thesamples in various frequency ranges are shown in Figure 5e sound absorption depends upon the thickness of thematerial amongst other factors [21 22] e reason can beattributed to the fact that the kinetic energy of the incidentsound wave gets converted to a low level of heat energy whenit passes through a thicker structure

(a) (b)

Figure 2 (a) Color and (b) white adhesive-bonded nonwoven recycled cottonpolyester samples

Advances in Materials Science and Engineering 3

icker structure absorbs sound waves by causingfrictional loss between sound wave and fiber therebydampening the effects of the propagating sound waveAnother factor was the tortuosity component Recycledcottonpolyester-based nonwoven samples can be observedthat while frequency increases the sound absorption coef-ficient (SAC) of all samples WC CC WP CP WCP andCCP also increases Similarly while thickness increases thesound-absorbing performance also increases At the highestfrequency of 4000Hz the SAC values of WC CC WP CPWCP and CCP are 04 068 04 065 055 and 072respectively e calculated average SAC values of WC CCWP CP WCP and CCP which are 0156 0312 01820331 0232 and 0361 also reveal the same Fibers inter-locking in nonwovens are the frictional elements thatprovide resistance to acoustic wave motion To design arecycled nonwoven web to have a high sound absorptioncoefficient porosity should increase along with the propa-gation of the sound wave [23] e recycled nonwovenporous structure possessed excellent performance for theabsorption of high-frequency sound waves especially above4000Hz [16 24]

32 SEM Analysis Figure 4 shows the SEM image ofreclaimed nonwoven fabric from which the perimeters aremeasured with Scalex PlanWheel XLUe recycled cottonpolyester fibersrsquo nonwoven samples are measured threetimes and the final average values were taken as a fiberperimeter e surface area of the fibers was calculated bymultiplying the perimeter and the total fiber length in thefabrice surface area of the nonwoven fabrics of 25times 4 wasobtained as per the ASTM Standard ASTM E 2809e samefinding was observed by [17 25]

33 Influenceofickness In this study sound absorption inporous materials was concluded as low-frequency soundabsorption has a direct relationship with thickness isstudy shows a high increase of sound absorption at lowfrequencies as the material gets thicker the sound ab-sorption property decreases as shown in Figure 6 Howeverat higher frequencies thickness has an insignificant effect onsound absorption e results revealed that the thicker thematerial the better sound absorption values on the middlevalue of the thickness of the sample e color cottonpolyester nonwoven CCP with a thickness of 131mmresults with an average SAC of 0361 which is higher thanCC WC WP CP and WCP nonwoven fabrics When thethickness of recycled nonwoven is less than 35mm littlesound absorption is achieved if the thickness is more903mm best sound absorption is achieved e samefinding was experimented by Shoshani and Yakubov [23]

34 Influence of Density Figure 7 shows that as the densityincreases the sound absorption coefficient of the sampleincreases A study by Koizumi et al [16] showed an increaseof sound absorption values in the middle and higher fre-quency as the density of the samples was increased Whenthere is an increase in areal density there is increase in sound

(a) (b)

Figure 3 SEM image of recycled cottonpolyester nonwoven fibers

Figure 4 Impedance tube measurement setup


absorption coefficient for cotton polyester and cottonpolyester blend nonwovens e colored materials havemore density than white material due to the dying moleculecontent in the colored material

e energy losses increase as the surface frictionincreases thus the sound absorption coefficient in-creases Less dense and more open structure absorbs thesound of low frequencies of 500 Hz Denser structureperforms better for frequencies above than 2000 Hz Itreveals that the increase in density directly increases theSAC Colored nonwoven which has a difference indensity of 003 gcm3 while the white nonwoven depicts24 increases in SAC Color and white polyester non-woven having the difference in density of 008 gcm3

depicts 32 increase in mean SAC Cottonndashpolyesternonwoven has the difference of density 0025 gcm3 withincreases in mean SAC of 0361 e number of fibersincreases in thickness per unit area when the apparentdensity is large e same results were obtained by Wangand Torng [24]

35 InfluenceofPorosity eporosity of a porous material isdefined as the ratio of the volume of the voids in the materialto its total volume stated by Allard et al [17] Porosity (H) isgiven by

porosity (H) Va

Vm

(5)

where Va volume of the air in the voids and Vm totalvolume of the sample of the acoustical material being tested

Figure 8 shows the influence of porosity on sound ab-sorption of recycled cottonpolyester-based nonwoven uponbeing color and white Samplesrsquo values are 13774 1365614256 13956 14056 and 13897 the results exposed thatwhen comparing the porosity and microspores the mi-crospores satisfy the diffusion sound waves e SAC of theporous materials was highly dependent on the permeabilityof the materials Less porosity and less air permeability of thesamples permit the sound frequency lesser amount at low-frequency level but at a higher frequency the sound entersthe fine pores and experience friction between the fibers andadhesiveness thus performing with higher absorption ofsound energy

36 Influence of Airflow Resistance Figure 9 shows the re-lationship between specific airflow resistance and sound ab-sorption coefficient It can be inferred that higher airflowresistance always gives better sound absorption values esound absorption property was influenced by a high increase inairflow With a high increase of airflow resistance and anincrease in density of fabric the sound absorption property isalso highly affected e airflow resistance of the color non-woven is about 356ndash389 ccscm2 with SAC of 031 to 036

It is clear that where the fabric density increased theairflow resistance decreased due to increased resistance toairflow caused by the consolidation of the web but alsoincreases the short fiber content which will occupy the airvoids e color polyester sample has the highest airflowresistance value with the SAC of 033 which is greater thanthat of WC CC WP CP WCP and CCP the same resultwas obtained by Teli [19] Fera [26] and Sengupta [20] Itcan be inferred that higher airflow resistance always givesbetter sound absorption values

37 Influence of ermal Conductivity e thermal insu-lation properties of the samples were measured in terms ofthe thermal conductivity e thermal conductivities ofvarious samples are shown in Figure 10 e better thethermal conductivity the better the insulation property

Low values of the thermal conductivity imply higherresistance to conduction of the heat through the materialWith the increase in temperature the thermal conductivity

Table 1 Physical properties of air-laid recycled nonwovens

Sample ID ickness Density (gcm3) Porosity Air permeability (CCSC m2) ermal conductivity (WmK)WC 12 0144 0897 345 0123CC 128 015 0891 356 0126WP 131 0162 0884 378 0129CP 132 0168 0898 389 013WCP 129 0167 0893 359 0127CCP 131 0174 0888 364 0128STDEV 04416 00115 000534 1589 00025

0 1000 2000 3000 4000 5000

Frequencyndash01

0

01

02

03

04

05

06

07

08

SAC

WPCPWC

CCWCPCCP

Figure 5 Variation of sound absorption coefficient with frequency


increases for all samples Two-layer mats with 50 recycledcotton fiber along with 50 recycled fiber provided one ofthe best insulation properties ese results showed that itis possible to develop samples that show similar thermalconductivity as that of 100 recycled cotton and polyesterfiber e thermal conductivity for the color polyestermaterial is about 013WmK which has SAC of 033 whichis higher than that of the WC CC WP CP WCP andCCP ese samples were suitable for roof ceiling

insulation applications in a building e study has beenconducted in [22]

38 Sound Resistance Performance of the Recycled CottonPolyester Nonwovens e chemically bonded nonwovenswhile tested for the sound resistance with 30 dB to 70 dBshowed that the increase in the number of the layer increasesthe sound resistance e average sound resistance

WC CC WP CP WCP CCP

12 128 131 132 129 131

015 031 018 033 0232 0361

Thickness (mm)Sound absorptioncoefficient

02

4

6

8

10

12

14

16

Figure 6 Influence of thickness on sound absorption coefficient

WC CC WP CP WCP CCP

0144 015 0162 0168 0167 0174

015 031 018 033 0232 0361

0005

01015

02025

03035

04

Bulk density (gcm3)

Sound absorptioncoefficient

Figure 7 Influence of density on sound absorption coefficient

WC CC WP CP WCP CCP

13774 13656 14256 14056 13956 13897

015 031 018 033 0232 0361

ndash200

20406080

100120140160

Porosity


Figure 8 Influence of porosity on sound absorption coefficient


percentage values for the three-decibel values are shown inFigure 11

e nonwovens of recycled color and white cotton colorand white polyester and color and white cottonndashpolyesterblend show approximately 15 27 and 35 sound re-sistance with fabric to source distance of 25 cm 50 cm and75 cm e reclaimed fibersrsquo nonwovens of color and whitecotton color and white polyester and color and whitecottonndashpolyester blend showed approximately 17 33and 42 sound resistance with fabric to source distance of

25 cm 50 cm and 75 cm ese results also reveal that thesound resistance increases the distance between the fabricand the source increases as stated by [20]

4 Conclusion

e automotive and building interiors made up of recycledfibers are in potential market growth e recycled fibernonwoven as thermal insulation and acoustic absorptionmaterial were developed by using the fibers recycled fromthe waste fabrics of cotton (color and white) polyester (colorand white) and cottonndashpolyester blend (color and white)collected from the garment industries e nonwovens aretested for acoustic absorption by ASTM E 1050 It is ob-served that polyester fiber nonwoven has the highest ab-sorption coefficient in lower frequency levels and higherfrequency levels e recycled polyester nonwoven fabricsare having high total surface area which is influenced by thedenier and cross-sectional structure of the fibers in thenonwoven fabrics Recycled polyestercotton mats (CC andCCP) showed the best thermal insulation and acousticabsorption CP and WCP nonwoven mats were absorbingmore than 70 of the incident noise (50ndash4000Hz) erewere no significant changes in the thermal insulation andacoustic properties of the recycled nonwoven mats whenevaluated under high humidity conditions Similarly whilethickness is increased sound-absorbing performance ofpolyester samples WP CP and CCP also increases at thehighest frequency of 4000Hz e SEM images of fibers aredetached from the resin surface due to poor interfacialbonding Pulled-out fibers are visible for composites with 5wt fiber content and 3mm length However the com-posite with 15 wt fiber and 12mm length shows goodmatrixfiber adhesion Hence it is concluded that thenonwoven made of recycled polyester with its closerstructure and higher sound-absorbing percentage of 72 ismuch suited for interiors in building and automotives ecotton (color and white) polyester (color and white) andcottonndashpolyester blend (color and white) are also havingsound absorption percentage of 73 is much suited for

WC CC WP CP WCP CCP

345 356 378 389 359 364

015 031 018 033 023 0361

ndash505

1015202530354045

Airflow resistance(ccscm2)Sound absorptioncoefficient

Figure 9 Influence of airflow resistance on sound absorption coefficient

WC CC WP CP WCP CCP

Thermal conductivity (WmK)

0118

012

0122

0124

0126

0128

013

0132


Figure 10 Influence of thermal conductivity

Sound resistance ()

WC CC WP CP CCPWCP102830

123134

113036

143843

164045

184964

010203040506070

dB

25cm50cm75cm

Figure 11 Sound resistance performance of recycled cottonpolyester nonwovens


interiors in sound absorption of 76 and 82 at 4000Hze major application of these developed nonwovenproducts may be suggested for floor covering and wallcoverings

Data Availability

No data were used to support this study

Conflicts of Interest

e authors declare that they have no conflicts of interestregarding the publication of this paper

References

[1] httpswwwchericorgresearchtechperiodicalsdoiphpart_seq=1043451

[2] D Bhatia A Sharma U Malhotra et al ldquoRecycled fibers anoverviewrdquo International Journal of Fiber and Textile Researchvol 4 pp 77ndash82 2014

[3] A Roznev ldquoRecycling in textilesrdquo Supply Chain Managementvol 19 no 1 pp 1ndash20 2011

[4] D M S Al-Homoud ldquoPerformance characteristics andpractical applications of common building thermal insulationmaterialsrdquo Building and Environment vol 40 no 3pp 353ndash366 2005

[5] A C Schmidt A A Jensen A U Clausen O Kamstrup andD Postlethwaite ldquoA comparative life cycle assessment ofbuilding insulation products made of stone wool paper wooland flaxflaxrdquo e International Journal of Life Cycle Assess-ment vol 9 no 1 pp 53ndash66 2004

[6] Y Lee and C Joo ldquoSound absorption properties of recycledpolyester fibrous assembly absorbersrdquo AUTEX ResearchJournal vol 3 pp 78ndash84 2003

[7] T Dias R Monaragala P Needham and E Lay ldquoAnalysis ofsound absorption of tuck spacer fabrics to reduce automotivenoiserdquo Measurement Science And Technology vol 18 no 8pp 2657ndash2666 2007

[8] Y Liu and H Hu ldquoSound absorption behavior of knittedspacer fabricsrdquo Textile Research Journal vol 80 pp 1949ndash1957 2010

[9] J Zach A Korjenic V Petranek J Hroudova and T BednarldquoPerformance evaluation and research of alternative thermalinsulations based on sheep woolrdquo Energy and Buildingsvol 49 pp 246ndash253 2012

[10] M S Sakthivel T Ramachandran M G ArchanaJ Ezhilanban and V M S Sivajith Kumar ldquoSustainable non-woven fabric composites for automotive textiles usingreclaimed FIBRESrdquo International Journal of EngineeringResearch and Development vol 4 pp 11ndash13 2012

[11] M D Stanciu I Curtu C Cosereanu et al ldquoResearch re-garding acoustical properties of recycled compositesrdquo inProceedings of the 8th International DAAAM Baltic Confer-ence Industrial Engineering Tallinn Estonia 2012

[12] K W Corscadden J N Biggs and D K Stiles ldquoSheeprsquos woolinsulation a sustainable alternative use for a renewable re-sourcerdquo Resources Conservation and Recycling vol 86pp 9ndash15 2014

[13] B Wierman ldquoNew frontiers for fiber-based noise controlsolutionsrdquo Sound and Vibration vol 44 p 14 2010

[14] W O Ogunbowale P Banks-lee K A Bello et al ldquoe effectsof fiber type and layering structure on the acoustical

absorptive properties of nonwovenrdquo Continental JournalApplied Sciences vol 6 pp 19ndash30 2011

[15] Y Shoshani ldquoStudies of textile assemblies used for acousticcontrolrdquo Technical Textiles International vol 2 no 3pp 32ndash34 1993

[16] T Koizumi N Tsujiuchi and A Adachi ldquoe development ofsound absorbing materials using natural bamboo fibersrdquoHigh-Performance Structure and Composites Book WIT PressSouthampton UK 2002

[17] J F Allard C Depollier and P Guignouard ldquoFree fieldsurface impedance measurements of sound-absorbing ma-terials with surface coatingsrdquo Applied Acoustics vol 26 no 3pp 199ndash207 1989

[18] F M Saleem ermal and mechanical investigation of fiber-reinforced epoxy PhD thesis Mechanical Engineering De-partment University of Technology Baghdad Iraq 2006

[19] M D Teli ldquoEfficacy of nonwoven materials as sound insu-latorrdquo Indian Journal of Fiber and Textile Research vol 322007

[20] S Sengupta ldquoSound reduction by needle-punched nonwovenfabricsrdquo Indian Journal of Fiber amp Textile Research vol 35pp 237ndash242 2009

[21] F Asdrubal Survey on the Acoustical Properties of NewSustainable Materials for Noise Control Euronoise TampereFinland 2006

[22] M Kuccediluk and Y Korkmaz ldquoe effect of physical parameterson sound absorption properties of natural fiber mixed non-woven compositesrdquo Textile Research Journal vol 82 no 20pp 2043ndash2053 2012

[23] Y Shoshani and Y Yakubov ldquoNumerical assessment ofmaximal absorption coefficients for nonwoven fiberwebsrdquoApplied Acoustics vol 59 no 1 pp 77ndash87 2000

[24] C-N Wang and J-H Torng ldquoExperimental study of theabsorption characteristics of some porous fibrous materialsrdquoApplied Acoustics vol 62 no 4 pp 447ndash459 2001

[25] S Santhanam M Bharani and S Temesgen ldquoRecycling ofcotton and polyester fibers to produce nonwoven fabric forfunctional sound absorption materialrdquo Journal of NaturalFibers vol 16 pp 3-4 2018

[26] T F Fera ldquoManufacture of reclaimed fiber non-woven forsound absorptionrdquo Journal of Material Sciences amp Engi-neering vol 7 p 5 2018


properties and web properties [6] A study was conducted onthe sound absorbency of a novel knitted spacer fabric thatcan be applied to automotive interior parts and has thepotential for greater sound absorbency than conventionalplain knitted fabrics [7 8] Recently noise absorbent textilematerials especially nonwoven structures or recycled ma-terials have been widely used because of the low productioncosts and they are being aesthetically appealing [9ndash11]Recycled polyester (RPET) fiber is derived from the post-consumer waste of plastic bottles which are a potentialsource of raw material for reducing environmental pollution[12] A study has been reported on the development ofinsulation materials from recycling cotton fiber with com-parable properties as that of conventional materials [13] Inanother recent study the authors highlighted the quantityissues of alterative recycled polyester materials available inthe market to meet the demand for the building sectoralthough recycled cotton materials are very good insulatorse absorption of sound mainly results from the dissipationof acoustic energy due to viscosity and heat conductivity ofthe medium Differences in pore structure due to differentfiber orientation and random arrangement of fibers producesamples with small pores and a higher amount of fiber-to-fiber contact points which ends in better sound absorptionproperties [14] In this study chemically bonded nonwovenswere manufactured from reclaimed fiber and tested for thesound absorption performance e sound absorptioninfluencing factors such as thickness density air perme-ability porosity and thermal conductivity were measuredaccording to the ASTM Standard and the purpose of con-struction industry applications

2 Experimental Work

21 Materials e raw materials used in this research areldquocut and sewrdquo knitwear production waste materials ewaste materials were collected from knitwear garment in-dustries then segregated depending on their colors andprepared for recycling to process in waste recycling ma-chines ese wastes are then fed into the reused fabricopener machine to obtain recycled fibers e recycled fiberis then converted into a web structure with different densityby using the mechanical carding process in the cardingmachine to form air-laid webs and the binder used here ispolyvinyl acetate (PVA) as shown in Figure 1 e bindersaturates on the surface layers and does not penetrate far inthe structure which is normally quite thick

e spray adhesive bonding is an exact measure of thenumber of binders applied uniform binder distribution and asoft fabric handlee adhesive add-on percentage is taken careof to maintain at 20 Precaution is taken to avoid the excessiveor lesser flow of adhesive through the sprayer By the calendarroller pressure the fibrous layer is converted into nonwovenfabric [15] e produced recycled cottonpolyester samplessuch as cotton (color and white) polyester (color and white)and cottonndashpolyester blend (color andwhite)WCCCWPCPWCP andCCP sampleswere preparedepreferred samplesof proportions with 6ndash8mm thick 80mm wide and 200mmlong were developed to measure the sound absorption

coefficient Figure 2 shows the prepared samples of color (a) andwhite adhesive-bonded (b) recycled nonwovens

e physical properties of nonwoven are fabric thick-ness density porosity air permeability and thermal con-ductivity were tested according to the ASTM standard andphysical properties were tested to measure the influence ofthe acoustic absorption coefficient of recycled nonwovens

22 Methods of Testing

221 ickness e thickness tester is a specializedequipment to determine the thickness of nonwoven fabricsthe mean value of all the readings of thickness that weredetermined to the nearest 001m is calculated and the resultis the average thickness of the sample under test e fabricthickness was determined by ASTM D 5729 standardmethod

222 Density A study by Koizumi et al [16] showed theincrease of sound absorption value in the middle and higherfrequency as the density of the sample increased especimen with 12 cm diameter and 80 cm2 areas were cut outrandomly and weighed Average of 20 observations wastaken for each sample and expressed in kgm2 e densitywas calculated by using the following relationship

density Wt

kgm3 (1)

where w is the weight of the sample per unit area deter-mined following the standard method ASTM D 3776mmass and V volume e SI unit of density is kgm3Water of 4degC is the reference ρ 1000 kgm3 1 kgdm3 1 kgl or 1 gcm3 1 gml

223 Porosity e porosity of a porous material is definedas the ratio of the volume of the voids in the material to itstotal volume is stated by Allard et al [17] e followingequation defines porosity as

porosity (H) Va

Vm

(2)

where Va volume of the air in the voids and Vm totalvolume of the sample of the acoustical material being testede porosity was found out with ASTM B 809

Figure 1 Schematic representation of adhesive bonding




Q VI


K Qts

TB minus TA

1113888 1113889TA + 2TA

r

tA + tS

41113874 1113875 +

tSTB

2r1113874 1113875

(3)







SR dBwos minus dBws

dBwostimes 100 (4)





(a) (b)







(a) (b)








porosity (H) Va

Vm

(5)









0 1000 2000 3000 4000 5000

Frequencyndash01

0

01

02

03

04

05

06

07

08

SAC

WPCPWC

CCWCPCCP






WC CC WP CP WCP CCP

12 128 131 132 129 131

015 031 018 033 0232 0361


02

4

6

8

10

12

14

16


WC CC WP CP WCP CCP

0144 015 0162 0168 0167 0174

015 031 018 033 0232 0361

0005

01015

02025

03035

04

Bulk density (gcm3)



WC CC WP CP WCP CCP

13774 13656 14256 14056 13956 13897

015 031 018 033 0232 0361

ndash200

20406080

100120140160

Porosity







4 Conclusion


WC CC WP CP WCP CCP

345 356 378 389 359 364

015 031 018 033 023 0361

ndash505

1015202530354045



WC CC WP CP WCP CCP


0118

012

0122

0124

0126

0128

013

0132



Sound resistance ()


123134

113036

143843

164045

184964

010203040506070

dB

25cm50cm75cm




Data Availability




References































Q VI


K Qts

TB minus TA

1113888 1113889TA + 2TA

r

tA + tS

41113874 1113875 +

tSTB

2r1113874 1113875

(3)







SR dBwos minus dBws

dBwostimes 100 (4)





(a) (b)







(a) (b)








porosity (H) Va

Vm

(5)









0 1000 2000 3000 4000 5000

Frequencyndash01

0

01

02

03

04

05

06

07

08

SAC

WPCPWC

CCWCPCCP






WC CC WP CP WCP CCP

12 128 131 132 129 131

015 031 018 033 0232 0361


02

4

6

8

10

12

14

16


WC CC WP CP WCP CCP

0144 015 0162 0168 0167 0174

015 031 018 033 0232 0361

0005

01015

02025

03035

04

Bulk density (gcm3)



WC CC WP CP WCP CCP

13774 13656 14256 14056 13956 13897

015 031 018 033 0232 0361

ndash200

20406080

100120140160

Porosity







4 Conclusion


WC CC WP CP WCP CCP

345 356 378 389 359 364

015 031 018 033 023 0361

ndash505

1015202530354045



WC CC WP CP WCP CCP


0118

012

0122

0124

0126

0128

013

0132



Sound resistance ()


123134

113036

143843

164045

184964

010203040506070

dB

25cm50cm75cm




Data Availability




References

































(a) (b)








porosity (H) Va

Vm

(5)









0 1000 2000 3000 4000 5000

Frequencyndash01

0

01

02

03

04

05

06

07

08

SAC

WPCPWC

CCWCPCCP






WC CC WP CP WCP CCP

12 128 131 132 129 131

015 031 018 033 0232 0361


02

4

6

8

10

12

14

16


WC CC WP CP WCP CCP

0144 015 0162 0168 0167 0174

015 031 018 033 0232 0361

0005

01015

02025

03035

04

Bulk density (gcm3)



WC CC WP CP WCP CCP

13774 13656 14256 14056 13956 13897

015 031 018 033 0232 0361

ndash200

20406080

100120140160

Porosity







4 Conclusion


WC CC WP CP WCP CCP

345 356 378 389 359 364

015 031 018 033 023 0361

ndash505

1015202530354045



WC CC WP CP WCP CCP


0118

012

0122

0124

0126

0128

013

0132



Sound resistance ()


123134

113036

143843

164045

184964

010203040506070

dB

25cm50cm75cm




Data Availability




References

































porosity (H) Va

Vm

(5)









0 1000 2000 3000 4000 5000

Frequencyndash01

0

01

02

03

04

05

06

07

08

SAC

WPCPWC

CCWCPCCP






WC CC WP CP WCP CCP

12 128 131 132 129 131

015 031 018 033 0232 0361


02

4

6

8

10

12

14

16


WC CC WP CP WCP CCP

0144 015 0162 0168 0167 0174

015 031 018 033 0232 0361

0005

01015

02025

03035

04

Bulk density (gcm3)



WC CC WP CP WCP CCP

13774 13656 14256 14056 13956 13897

015 031 018 033 0232 0361

ndash200

20406080

100120140160

Porosity







4 Conclusion


WC CC WP CP WCP CCP

345 356 378 389 359 364

015 031 018 033 023 0361

ndash505

1015202530354045



WC CC WP CP WCP CCP


0118

012

0122

0124

0126

0128

013

0132



Sound resistance ()


123134

113036

143843

164045

184964

010203040506070

dB

25cm50cm75cm




Data Availability




References
































WC CC WP CP WCP CCP

12 128 131 132 129 131

015 031 018 033 0232 0361


02

4

6

8

10

12

14

16


WC CC WP CP WCP CCP

0144 015 0162 0168 0167 0174

015 031 018 033 0232 0361

0005

01015

02025

03035

04

Bulk density (gcm3)



WC CC WP CP WCP CCP

13774 13656 14256 14056 13956 13897

015 031 018 033 0232 0361

ndash200

20406080

100120140160

Porosity







4 Conclusion


WC CC WP CP WCP CCP

345 356 378 389 359 364

015 031 018 033 023 0361

ndash505

1015202530354045



WC CC WP CP WCP CCP


0118

012

0122

0124

0126

0128

013

0132



Sound resistance ()


123134

113036

143843

164045

184964

010203040506070

dB

25cm50cm75cm




Data Availability




References
































4 Conclusion


WC CC WP CP WCP CCP

345 356 378 389 359 364

015 031 018 033 023 0361

ndash505

1015202530354045



WC CC WP CP WCP CCP


0118

012

0122

0124

0126

0128

013

0132



Sound resistance ()


123134

113036

143843

164045

184964

010203040506070

dB

25cm50cm75cm




Data Availability




References






























Data Availability




References





























garment waste recycled cotton/polyester thermal and...

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