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Abstract

This paper aims to examine the performance of home furnishing applications such as curtains, floor coverings, blankets or pillows to be air permeable, thermal insulators or sound absorbing materials. Two types of fillers, banana fibers and mini Styrofoam balls, were used in different proportions. Plain 1/1, twill 2/2, and sateen four weave structures made of jute-cotton fabrics were implemented by 12 and 16 picks per inch. The KES-F7 Thermo Labo apparatus was used to test the thermal conductivity of fabrics, SDL ATLAS M021 A tester was used to test air permeability, and the sound absorption coefficient (SAC) was measured using the impedance tube. The effect of different number of fabric layers (1, 2 or 3), different types of fillers between two layers of fabric and an air gap between the back plate and fabric samples during the sound absorption test was investigated. Along with two sewing techniques, lockstitch and 3-thread overlock stitch, two layers of optimal sound absorbing samples were joined together to examine the effect of different fillers on fabric properties. Radar chart, ANOVA analysis and coefficient of correlation were used as statistical tools to analyse the results. It was found that the lockstitch demonstrated better sewing performance compared to 3-thread overlock stitch. For triple-layered fabric with a twill structure, increasing the air gap between the back plate of the impedance tube and the fabric sample shifted the resonance frequency from 1600 Hz (SAC 0.97) to 1000 Hz (SAC 0.97). When using banana fibers with sateen structure, the resonance frequency remained at 6300 Hz but with an improved of SAC 0.96 compared to SAC 0.93. On the other hand, combining Styrofoam balls and banana fibres as fillers with a twill structure shifted the resonance frequency from 6300 Hz (SAC 0.93) to 4000 Hz (SAC 0.93).

Keywords

Banana fibers home furnishings acoustic properties jute-cotton fabrics sound absorption coefficient impedance tube thermal conductivity KES-F7 thermo labo apparatus air permeability lockstitch

Introduction

In recent years, there has been an interest in using natural textile materials in many applications due to their light weight, good strength, low cost and appropriate thermal properties.^1,2,3 Noise pollution is a serious problem and many researchers tend to use green composites to overcome health problems such as mental stress, mood changes problems hearing, tiredness and social negative communication which result from noise sources by using sound absorbing materials.⁴ Nowadays, using of plant fibres as sound absorbers increased due to their biodegradable and eco-friendly characteristics.^5,6,7,8 Many researchers applied different techniques to dissipate the acoustic energy which is measured by the sound absorption coefficient (SAC) and it ranges from 0 to 1.⁹ The applications of acoustic textiles may be fabricated from textile materials only or by adding a definite type of polymer to add certain characteristics such as fire retardant or mechanical properties or to be a means to adhere fibres with each other. The basic elements of textile materials are divided into fibres, woven, knitted and nonwoven fabrics¹⁰ that were used to enhance acoustic absorption. Composites based on natural fibres are considered as good sound-absorbing materials and many studies are conducted on their performance according to the fibre type.^{11,12,13,14,15,16,17,18} Increasing the amount of fibres in composite materials enhances the sound absorption coefficient because a higher volume fraction of resin means a smooth surface and more reflection of sound waves instead of moving into the material structure.^19,20,21 Natural source fibres such as; blended kapok fibre with polypropylene fibre as non-woven composites and gave respectable sound retention behaviour at the frequency range from 250 Hz to 2000 Hz.²² Jute fibres are commonly used in various applications as sound absorbers or thermal insulators due to their porous structure and good mechanical properties. However, the rough and stiff surface of jute fibres poses a challenge. To overcome these limitations, blending jute fibres with cotton fibres is a commonly employed solution.^{23,24,25,26,27,28} Woven fabrics are known for their sound-absorbing properties due to their porous structure in different weave patterns. Xie et al.²⁹ conducted a study to investigate the physical and acoustic properties of jute fabrics, focusing on the effects of warp and weft yarn densities, thickness, weight, and weave structure on sound absorption. Jeyaguru et al.³⁰ examined the impact of fabric weave structures (plain, twill, and basket weaves) in hybrid composites of blended Kevlar-Hemp fabrics on acoustic and mechanical behaviour. Basket weave exhibited the highest sound transmission, while twill structure showed better mechanical characteristics. Yarn parameters such as the type of raw material, yarn count, and spinning technology also affect the acoustic properties, with lower linear yarn density improving sound absorption.³¹ Fabrics woven using rotor-spun yarns demonstrated greater sound absorption compared to compact or ring-spun yarns. Additionally, it was observed that increasing the number of fabric layers and using finer weft yarns resulted in higher values of the noise reduction coefficient.³² Woven fabrics with lower pick densities and lower yarn twists exhibited improved sound absorption compared to higher densities and twists.³³ Islam et al.³⁴ investigated the structure of fabrics and discovered that plain and twill fabrics exhibit the highest levels of seam efficiency and strength, respectively. Plain fabrics have higher seam efficiency than other textiles with the same linear density of sewing threads. In terms of nonwoven fabrics as sound insulators, studies by Tascan and Vaughn^21,35 examined the effects of fibre morphology and two different nonwoven fabric technologies (needle punched and vertically lapped) on air permeability and fabric density. The results indicated a positive relationship between fabric density and sound absorption, with increased air permeability leading to decreased sound insulation. However, this finding contrasts with the results of Kang et al.³⁶ Zakriya et al.³⁷ investigated the use of nonwoven jute fabric-based composite materials as effective sound absorbers and thermal insulators by filling them with different polymers. Increasing the amount of jute fibres in nonwoven blended fabrics made of jute-coir fibres enhanced the acoustic characteristics.³⁸ While most research has focused on utilizing natural fibres’ properties through different resin types in composite applications or by forming nonwoven fabrics using various techniques to enhance sound absorption, this research aims to develop effective sound-absorbing materials by using blended jute-cotton fabrics with home furnishings applications such as curtains, cushions or upholstery. Effect of number of fabric layers, fabric weave structure, picks per inch, fabric thickness, air permeability and different types of fillers on sound absorption performance were studied. Optimal fabric samples of sound absorption were sewn to examine the ability of different fillers to enhance sound absorption or reduce sound reverberation in upholstery applications. In addition, the effect of fabric parameters was examined to obtain the optimal performance of air permeability and thermal insulation of home furnishings applications.

Materials and methods

Samples’ preparation

The first section of samples’ preparation is to study the performance of home furnishings such as curtains, floor coverings or blankets of thermal conductivity and air permeability. Table 1 displays three different of fabric factors will be studied; number of layers (1, 2 and 3), fabric weave structure and picks per inch (12 and 16), while maintaining the same warp density: 24 threads per inch. Figure 1 shows the pattern of three different woven structures that were employed; Plain 1/1, Twill 2/2, and Sateen 4Harness. The weft yarns were ring spun yarns which composed of jute fibers with a tex value of 145, while the warp yarns were made of cotton fibres with a tex value of 40.

Table 1.

Samples’ specification of different layers of fabric.

Sample no.	Sample code	No. of layers	Fabric structure	Picks/inch
1	P12	1	Plain	12
2	--	2	Plain	12
3	--	3	Plain	12
4	P16	1	Plain	16
5	--	2	Plain	16
6	--	3	Plain	16
7	T12	1	Twill	12
8	2T12	2	Twill	12
9	3T12	3	Twill	12
10	T16	1	Twill	16
11	--	2	Twill	16
12	--	3	Twill	16
13	S12	1	Sateen	12
14	2S12	2	Sateen	12
15	3S12	3	Sateen	12
16	S16	1	Sateen	16
17	--	2	Sateen	16
18	--	3	Sateen	16

Figure 1.

The pattern of weave structures (plain 1/1, twill 2/2 and sateen 4).

The second section is to examine the home furnishings performance to absorb sound waves. After measuring the sound absorption of coefficient (SAC) of single layers of fabric (Table 1), the optimal values of SAC will be selected to be sewn together. Then acoustic performance of double and triple layers of optimal samples, T12 and S12 as it will be shown in results, was analysed. Table 2 displays samples’ specifications that were selected due to higher values of sound absorption average (SAA) as it is shown in Figure 9. Additionally, the effect of different types of fillers between two layers of fabric, which can be applied in home furnishings such as upholstery fabrics or pillows, was analysed.

Table 2.

Fabric samples’ specifications.

Sample code	No of layers	Fabric structure
2T12	2	Twill
2S12	2	Sateen
3T12	3	Twill
3S12	3	Sateen

To examine the acoustic performance of different fillers, two layers of optimal fabric samples of sound absorption performance for each weave structure (T12 or S12) were sewn together. Lockstitch and 3-thread overlock stitch using the same sewing thread polyester (42/2 Ne) provided by El-Negmah company were applied. Singer and over JUKI machines were used by four stitches per centimetre for each of them to determine the suitable sewing stitch for sewing these woven cotton/jute fabrics.

Table 3 shows three different types of fillers were packed between two layers of fabric which were the optimal samples of sound absorption performance (2T12 and 2S12). These were filled with constant weight percentage, which is proportional to the weight of the single layer (5%) of each weave structure, of mini Styrofoam balls® and banana fibers as fillers. Commercial Styrofoam balls® are made of polystyrene foam and the diameter is between (2 – 5) mm. Banana fibers’ diameter ranges between (80 – 300) micron and fiber length is between (80 – 120) mm. Banana fibers was cut into (2.2) cm to be homogenous as a filler of fabric samples. For instance, 1T, which consists of two double layers of T12 (the optimal sample of twill structure), and 4S, which consists of two double layers of S12 (the optimal sample of sateen), are filled entirely with mini Styrofoam balls. 2T and 5S are filled with a combination of 50% mini Styrofoam balls and 50% banana fibers, while 3T and 6S are filled entirely with banana fibers. Figure 2 shows the shape of the fabric samples after sewing and different fillers used.

Table 3.

Specifications of fabric samples with different fillers.

Fabric samples	Strength of one layer (N/mm²)		Sample code	Filler type
Fabric samples	Warp direction	Weft direction	Sample code	Filler type
2T12			1T	100% mini styrofoam balls
	23.5	33.15	2T	50% mini styrofoam balls + 50% banana fibers
			3T	100% banana fibers
2S12			4S	100% mini styrofoam balls
	20.15	32	5S	50% mini styrofoam balls + 50% banana fibers
			6S	100% banana fibers

Figure 2.

Fabric samples with different fillers.

Testing and calculations

The thermal conductivity of various layers of the jute fabrics was determined using the KES-F7 Thermo Labo apparatus, ensuring that the heat transfer between the first plate at 30°C and the second plate at 20°C remained constant during measurement.

Air permeability was measured according to the standard test method ASTM D737, and SDL ATLAS M021 A tester was used to measure the samples.³⁹

The sewn seam strength and sewn seam efficiency of critical sewn seam assemblies with each fabric were calculated, because sewn seam strength and sewn seam efficiency vary with each fabric. Seam efficiency for both applied seam types; tensile strength and elongation were measured for fabrics and seams according to the standard test method ASTM D1683/D1683M-22.⁴⁰ In addition, sewing strength (N/mm²), sewing elongation percentage, and seam efficiency percentage were determined using an Instron tester (USA, 2005) and seam efficiency was calculated regarding the equation⁴¹:

Seam Efficiency % = (\frac{Seam Strength}{Fabric Strength}) * 100 .

According to the (ASTM, E., 1050-9) standard, sound absorption coefficient (SAC) was measured. Standard test method for impedance and absorption of acoustical materials was used including a tube, two microphones, and a digital frequency analysis system. American Society for Testing and Materials, Philadelphia, PA, 1990), the normal sound absorption coefficient was experimentally determined using a two-microphone impedance tube technique. Figure 3 shows the test setup utilized in the laboratory to evaluate the samples’ sound absorption coefficients using a B&K impedance tube type 4206. The impedance tube’s internal diameter is 30 mm and 100 mm, and the acoustic properties were measured in the frequency range from 100 to 6300 Hz. According to (ISO 10534-2), the frequency range in the third octave band could divided into low frequency range (125–1600 Hz) and high frequency range (500–6300 Hz). With this technique, a loudspeaker at one end of the tube generates a plane sound wave, which is then reflected by the specimen at the other end. The decay of sound energy is captured using two microphones positioned differently on the inner surface of the tube. The complex acoustic transfer function is used to calculate the reflection coefficient ‘R’ of the specimen. Therefore, the normal incidence sound absorption coefficient is determined to be equal to α = 1 - |R|².

Figure 3.

Setup of the impedance tube for sound absorption measurements.

To compare between the sound absorption performance of fabric samples made of blended jute-cotton fabrics, the average of sound absorption coefficient was calculated (SAC). The material is called sound absorption material when the SAC is greater than 0.210. Additionally when the SAC is greater than 0.56, the material is called high-efficiency sound-absorption material.⁴²

α = \frac{α 125 + α 250 + α 500 + α 1000 + α 2000 + α 4000}{6} .

All results presented and tabulated, by means values as bar charts or graphs by using Microsoft Excel. The significant effect between variables were statistically analysed according to ANOVA two way measurements based on IBM® SPSS® (SPSS Inc., IBM Corporation, NY, USA) Statistics Version 22 for Windows, The significant difference was located at p ≤ .05. The coefficient of correlation was calculated to summarize the relation between fabric factors and the studied properties. Based on radar chart,⁴³ the best samples of air permeability, thermal conductivity and sound absorption were investigated.

Results and discussion

Results are divided into two sections; section one investigates the relation between fabric samples such as number of layers, picks per inch, fabric weave structure, fabric thickness, air permeability and thermal conductivity. The best samples of air permeability and thermal insulation could be applied in home furnishings such as curtains. The second section is to test the ability of home furnishings such as curtains, cushions or upholstery to absorb sound waves. The performance of different number of fabric layers, air gap back the fabric samples and different fillers between two layers of fabric will be studied.

Thermal and air permeability performance of home furnishings

The first section is to investigate the performance of thermal insulation and air permeability of the blended jute- cotton fabrics to be used in home furnishings such as curtains. Table 4 shows the fabric specifications according to the number of fabric layers. Plain 1/1, Twill 2/2 and Sateen 4 with 12 and 16 picks per inch were used. For every structure, air permeability (cm³/cm²/sec), thermal conductivity (W/cm*°C), and the fabric thickness (mm) were measured.

Table 4.

Specification of different layers of fabric.

Sample no.	No. of layers	Fabric structure	Picks/inch	Air permeability (cm³/cm²/sec)	Thickness (mm)	Thermal conductivity (k)-(W/cm*°C)
1	1	Plain	12	34.4	1.1	0.00041
2	2	Plain	12	26.1	2.12	0.00045
3	3	Plain	12	22.6	3.29	0.00059
4	1	Plain	16	14.8	1.08	0.00042
5	2	Plain	16	8.73	2.1	0.00052
6	3	Plain	16	7.33	3.23	0.00053
7	1	Twill	12	89	1.15	0.0003
8	2	Twill	12	82.6	2.35	0.00038
9	3	Twill	12	57.9	3.55	0.000415
10	1	Twill	16	38.2	1.21	0.00033
11	2	Twill	16	25.1	2.45	0.00041
12	3	Twill	16	19	3.73	0.00043
13	1	Sateen	12	98	1.14	0.00029
14	2	Sateen	12	70.92	2.34	0.00035
15	3	Sateen	12	52	3.47	0.00042
16	1	Sateen	16	51.1	1.2	0.00032
17	2	Sateen	16	31.8	2.22	0.00037
18	3	Sateen	16	21.6	3.55	0.00041

Effect of fabric factors on air permeability

Table 5 shows that the number of layers, fabric structure and picks per inch are significantly affecting air permeability. There is a negative correlation between number of fabric layers and air permeability. In other words, increasing the number of layers results in a decrease in air permeability. Additionally, picks per inch are higher negatively correlated to air permeability compared to the number of layers.

Table 5.

Fabric factors affecting air permeability.

Factor	p-value	R
No. of layers	0.0058	−0.362
Fabric structure	0.0003	0.528
Picks/inch	0.0000	−0.644

Figure 4 shows that by increasing the number of picks per inch, air permeability decreases. Additionally, sateen structure has the highest values of air permeability because of its opened structure and more weft floats compared to plain and twill weave structures. For instance, the highest value of air permeability is with single layer of sateen structure and 12 picks per inch which makes this sample be suitable for home furnishings such as curtains.

Figure 4.

Effect of number of layers on air permeability.

Effect of fabric factors on thermal conductivity

Table 6 shows the correlation between the number of fabric layers, fabric weave structure, picks per inch and the thermal conductivity. Number of layers and the fabric structure are significantly moderate correlated to the thermal conductivity according their p-values and the coefficient of correlation. On the other hand, picks per inch are not significant to affect the values of thermal conductivity.

Table 6.

Fabric factors affecting thermal conductivity.

Factor	p-value	R
No. of layers	1.8E-05	0.636
Fabric structure	1.1E-05	0.667
Picks/inch	0.351	0.097

Figure 5 shows that at the same fabric structure by increasing the number of fabric layers, thermal conductivity increases. On the other hand, 16 picks per inch recorded higher values of thermal conductivity compared to 12 picks per inch. The lowest value of thermal conductivity was recorded with the single layer of sateen structure at 12 picks per inch which means that it is the suitable fabric to be as a thermal insulator in the upholstery applications such as curtains. Higher values of air permeability indicate to more air molecules that are trapped between fabric construction and effective thermal insulation.^44,45

Figure 5.

Effect of number of layers on thermal conductivity.

Effect of fabric factors on fabric thickness

Table 7 shows that the number of fabric layers and fabric structure are significantly related to the fabric thickness according the p-value (p < .05). The number of fabric layers is positively higher correlated to the fabric thickness compared to the fabric weave structure and picks per inch.

Table 7.

Fabric factors affecting fabric thickness.

Factor	p-value	R
No. of layers	9.2E-15	0.991
Fabric structure	0.034	0.071
Picks/inch	0.618	0.015

Figure 6 displays the effect of number of fabric layers on the fabric thickness. It is noted that the lowest values of fabric thickness are with plain weave structure at 16 picks per inch. This is due to the higher intersections between yarns that lead to more compactness in the weave structure and lower fabric thickness.

Figure 6.

Effect of number of layers on fabric thickness.

Correlation between fabric thickness, air permeability and thermal conductivity

Table 8 shows a negatively moderate correlation between fabric thickness and thermal conductivity because there is another factor affects these values such as air spaces that make as barriers. Air permeability has a major effect on thermal conductivity according to the higher value of coefficient of correlation (−0.72). It is negatively correlated to thermal conductivity due to more air molecules in the fabric construction result in an effective thermal insulation.⁴⁶

Table 8.

Correlation between fabric thickness, air permeability and thermal conductivity.

Fabric property	Thickness (mm)	Air permeability (cm³/cm²/sec)	Thermal conductivity (k)-(W/cm*°C)
Thickness (mm)	1	--	--
Air permeability (cm³/cm²/sec)	−0.32	1	--
Thermal conductivity (k)-(W/cm*°C)	0.559	−0.723	1

Ranking of fabric samples according to thickness, air permeability and thermal conductivity

Radar chart of the jute-cotton fabrics with three different layers are drawn in Figure 7 presenting their characteristics. Also, radar chart areas were calculated and ranked in Table 9 to select the higher ranked samples according to their optimal characteristics. The rank is according to higher values of air permeability, lower thermal conductivity and lower thickness of fabric samples to achieve the higher performance of home furnishings such as curtains, floor coverings or blankets. By calculating radar chart areas, it was found that sateen followed by twill structures by weft density 12 picks per inch ranked as 1^st and 2^nd respectively by a little difference in the radar chart areas.

Figure 7.

Radar chart of different layers of fabric samples.

Table 9.

Radar areas for different layers of fabric samples.

Sample code	Thickness (%)	Air permeability (%)	Thermal conductivity (%)	Radar chart area	Rank
P12, 1 layer	98	35	71	5574	7^th
P12, 2 layers	51	27	64	2752	12^th
P12, 3 layers	33	23	49	1517	17^th
P16, 1 layer	100	15	69	4095	8^th
P16, 2 layers	51	9	56	1655	15^th
P16, 3 layers	33	7	55	1078	18^th
T12, 1 layer	94	91	97	11,425	2^nd
T12, 2 layers	46	84	76	5981	5^th
T12, 3 layers	30	59	70	3486	9^th
T16, 1 layer	89	39	88	6386	4^th
T16, 2 layers	44	26	71	2623	13^th
T16, 3 layers	29	19	67	1655	16th
S12, 1 layer	95	100	100	12,534	1^st
S12, 2 layers	46	72	83	5698	6^th
S12, 3 layers	31	53	69	3232	11^th
S16, 1 layer	90	52	91	7610	3^rd
S16, 2 layers	49	32	78	3436	10^th
S16, 3 layers	30	22	71	1897	14^th

Acoustic performance of single layers

Figure 8 shows that the sound absorption coefficient (SAC) of all samples is fluctuated between 0.04 and 0.15 in the frequency range from 500 to 5000 Hz. At 6300 Hz, a significant increase in the SAC values is observed. Although there is an increase at 6300 Hz, the results are not acceptable to achieve a good sound absorbing material in home furnishings applications, so that the research suggested some factors that enhance the values of SAC of woven jute fabrics such as increasing the number of fabric layers, air gap between the fabric sample and the rigid back of the impedance tube, or adding different fillers between fabric layers.

Figure 8.

SAC of single layers.

Fabric factors affecting SAA

After computing the sound absorption average (SAA) for single layers in the scenario of high-frequency range,⁴⁷ as depicted in Figure 9. The sound absorption average (SAA) is calculated to express the average value of SAC for each sample at the high frequency range of sound waves (500 – 6500 Hz) and the samples which recorded the highest SAA values are selected. Among these samples, S12 and T12 exhibited the highest values of air permeability. This outcome suggests that fabrics with higher air permeability values serve as effective sound absorbers. This can be attributed to the presence of air molecules between yarns within the fabric structure, which results in increasing friction between sound waves and air molecules, leading to enhance sound wave attenuation.³⁵ The effect of fabric thickness on SAA is not consistent for all samples due to the effect of other variables such as fabric structure and amount of air molecules between the fabric construction.

Figure 9.

SAA values of single layers.

Radar chart areas of single layers of fabric

Radar chart of the single layer of fabric samples are depicted in Figure 10 presenting their characteristics. Also, radar chart areas were calculated and ranked in Table 10 after measuring the sound absorption average (SAA) for ranking the fabric samples and select the optimal samples to study the effect of multilayers of fabric and different fillers on sound absorption performance in home furnishings applications. By calculating radar chart areas, it was found that sateen and twill structures by weft density 12 picks per inch ranked as 1^st and 2^nd by a little difference in the radar chart area. These areas confirm the results of Figure 9 and ensure that these samples (S12 and T12) present the higher performance in all applied samples.

Figure 10.

Radar chart of single layers of fabric samples.

Table 10.

Radar areas of single layer of fabric samples.

Sample code	Thickness (%)	Air permeability (%)	Thermal conductivity (%)	SAA (%)	Radar area	Rank
P12	98	35	71	76.97348	12,938	4^th
T12	94	91	97	95.39449	22,283	2^nd
S12	95	100	100	99.99974	24,211	1^st
P16	100	15	69	76.97348	11,235	6^th
T16	89	39	88	59.86826	12,677	5^th
S16	90	52	91	65.13141	14,669	3^rd

Acoustic performance of double and triple layers

This section is to discuss the effect of the number of fabric layers, the air gap between fabric samples and the rigid back of the impedance tube, and different types of fillers between two layers of fabric. SAC of Low frequency range (100 Hz to 1600 Hz) and high frequency range (500 Hz to 6300 Hz) were measured for double and triple layers.

Effect of the number of fabric layers on SAC

Figure 11 compares between the performance of sound absorption of twill and sateen structure of samples 2T12, 2S12, 3T12 and 3S12 with different number of fabric layers. It is demonstrated that by increasing the number of layers of jute fabrics, the sound absorption behaviour of the triple layers enhanced compared to the double layers. For instance, the average of sound absorption coefficient (SAC) of 3S12 increased by (42% and 39%) at low and high frequencies respectively compared to 2S12.

Figure 11.

Effect of number of fabric layers on SAC.

Figure 12 displays the relation between number of fabric layers, SAC, air permeability and fabric thickness. By increasing the number of layers, air permeability decreased and SAC increased. This finding contradicts the previous result of single layers as it was shown in Figure 9. This is due to higher values of air permeability in single layers which potentially enhance their ability to trap a greater number of air molecules within the fabric structure, thus increasing the friction between air molecules and sound waves leads to higher sound attenuation. On the other hand, increasing the number of layers make the fabric more compact and dense which prevent transmission of sound waves. This finding confirms that there is an optimum value of air permeability to achieve the best results of sound absorption performance.³³

Figure 12.

Effect of No. of layers on SAC.

Effect of air gap of double and triple layers of fabric on SAC

Figure 13 shows the effect of three different mounting conditions; rigid backing (the samples were directly mounting on the rigid back of the tube), 3 cm and 6 cm air gaps between the samples and the rigid backing of the impedance tube on the SAC of a double layer from each of the two optimum fabric samples (2T12 and 2S12). It is revealed that, by increasing the air gap between the samples and the back plate from 3 cm to 6 cm, a significant increase in the SAC was obtained. In case of 2T12, the average of SAC at 3 cm and 6 cm are (0.25) and (0.35) respectively. Increasing the air gap shifted the resonance frequency (the frequency at which the maximum absorption coefficient occurs) from 1600 Hz (SAC 0.82) to 1250 Hz (SAC 0.85). Regarding 2S12, the average of SAC at 3 cm and 6 cm are (0.26) and (0.38) respectively. Increasing the air gap shifted the resonance frequency from 1600 Hz (SAC 0.82) to 1000 Hz (SAC 0.82). By increasing the air gap between the fabric sample and the rigid back wall, SAC values increased.⁴⁸

Figure 13.

Effect of air gap on SAC of a double layer.

Figure 14 demonstrates that, by increasing the air gap between the samples and the back plate from 3 cm to 6 cm, a significant increase in the SAC was obtained. In case of 3T12, the average of SAC at 3 cm and 6 cm are (0.35) and (0.49) respectively. Increasing the air gap shifted the resonance frequency from 1600 Hz (SAC 0.97) to 1000 Hz (SAC 0.97). Regarding 3S12, the average of SAC at 3 cm and 6 cm are (0.32) and (0.47) respectively. Increasing the air gap shifted the resonance frequency from 1600 Hz (SAC 0.96) to 1000 Hz (SAC 0.96).

Figure 14.

Effect of air gap on SAC of triple layers.

Radar chart areas of double and triple layers of fabric

Figure 15 and Table 11 show the radar chart results of sewed double and triple layers of T12 and S12 samples. The radar chart is based on higher values of air permeability, lower thickness and lower thermal conductivity to obtain the optimal samples of home furnishings applications to be as thermal insulators and sound absorbing materials such as curtains, blankets or floor coverings. By calculating radar chart areas, it was found that the sewed double layers of twill weave structure ranked as the first optimal sample followed by the double layers of sateen structure.

Figure 15.

Radar chart of double and triple layers of fabric samples.

Table 11.

Radar areas of double and triple layers of fabric samples.

Sample code	Air permeability (%)	Thickness (%)	Thermal conductivity (%)	SAC (%)	Radar chart area	Rank
T12, 2 layers	100	100	92	56.21302	19,569	1^st
S12, 2 layers	86	100	100	49.11243	18,150	2^nd
T12, 3 layers	70	66	84	100.00000	15,767	3^rd
S12, 3 layers	63	67	83	76.04396	13,118	4^th

Effect of type of fillers on SAC

This section discusses the ability of furnishings home such as upholstery, curtains or pillows to absorb sound waves. After joining two layers of the selected fabric together (T12 or S12) according the higher values of SSA, three different fillers were padded (Figure 2). In the beginning, this section discusses the sewing performance to form the shape of samples then effect of different of fillers on sound absorption performance will be analysed.

Effect of seam type and fabric structure on sewing performance

Table 12 and Figure 16, show the mechanical performance results of lockstitch and 3-thread overlock stitch which are used to sew the two layers of fabric samples together. The lockstitch records good sewing performance in twill and sateen structures according to its higher seam strength, seam efficiency (%) and seam elongation in weft and warp directions compared to 3-thread over the edge.

Table 12.

Sewing performance of lockstitch and 3-thread overlock stitch.

Stitch type	Sample code	Warp direction			Weft direction
Stitch type	Sample code	Seam strength (N/mm²)	Seam efficiency (%)	Seam elongation %	Seam strength (N/mm²)	Seam efficiency (%)	Seam elongation %
Lockstitch	2T12	2.77	11.42	12.37	2.87	8.67	7.74
Lockstitch	2S12	1.04	5.32	10.37	1.49	4.65	8.00
3-Thread overlock stitch	2T12	0.73	2.99	8.05	0.29	0.87	4.37
3-Thread overlock stitch	2S12	1.39	7.07	8.37	0.11	0.34	4.34

Figure 16.

Sewing performance of lockstitch and 3-thread overlock stitch.

Effect of fabric factors on sewing performance

Table 13 displays the significance effect of fabric factors on the seam performance according to p-values. It was found that the sewing stitch type and the sewing direction by the jute-cotton fabrics have a significant effect on the seam elongation and non-significant effects on the seam strength and seam efficiency.

Table 13.

Effect of seam type and fabric structure on sewing performance.

Characteristic	p-value
Characteristic	Fabric structure	Sewing stitch type	Sewing direction
Seam strength (N/mm²)	0.302	0.064	0.626
Seam efficiency (%)	0.467	0.083	0.202
Seam elongation (%)	0.497	0.002	0.002

Ranking seam type according sewing performance by radar charts’ area

Figure 17 shows the effect of the fabric direction; as it’s clear that sewing performance in the warp direction is higher compared to the weft direction. The sewing performance with twill structure is higher compared to fabric weave structure. Radar charts depict the sewing performance of T12 and S12 whereas the radar chart area was calculated for both samples (2T12 and 2S12), and both seam types. It was found that the radar chart area of the lock stitch is higher of the both weave structure.⁴⁹ All sewed samples were ranked by radar chart areas in Table 14. Therefore, lockstitch was applied to join fabric samples together due to its higher ranks in sewing performance.

Figure 17.

Radar charts of sewing performance of lockstitch and 3-thread overlock stitch.

Table 14.

Ranking sewing performance by using radar charts’ area.

Sample code	2T12		2S12
Stitch type	Lockstitch	3-thread overlock stitch	Lockstitch	3-thread overlock stitch
Seam strength in warp direction (%)	100	26.35	37.55	50.18
Seam efficiency in warp direction (%)	100	26.18	46.58	61.91
Seam elongation in warp direction (%)	100	65.08	83.83	67.66
Seam strength in weft direction (%)	100	10.10	51.92	3.83
Seam efficiency in weft direction (%)	100	10.03	53.63	3.92
Seam elongation in weft direction (%)	96.75	54.63	100	54.25
Radar chart area	43,018.55	3,205.03	15,721.67	6,739.84
Rank	1^st	4^th	2^nd	3^rd

Effect of different types of fillers and air gaps on SAC

Figure 18 displays the SAC of 1T and 4S at three different mounting conditions, rigid backing, 3 cm and 6 cm air gaps. It is demonstrated from the figures that, leaving an air gap between the sample and the back plate of the tube, improved the SAC significantly. In another meaning, the averages of SAC of 1T at rigid backing, 3 cm and 6 cm in the frequency range from 100 Hz to 1600 Hz are 0.08, 0.3 and 0.36 respectively. Also for 4S sample, the averages of SAC are 0.09, 0.32 and 0.38 for rigid backing, 3 cm and 6 cm correspondingly.⁵⁰

Figure 18.

100% Styrofoam balls filler with twill and sateen structure.

Moreover, by increasing the air gap from 3 cm to 6 cm, the resonance frequency in case of 1T shifted from 1250 Hz (SAC 0.81) to 800 Hz (SAC 0.78) which enhanced the sound absorption at low frequency. And in the case of 4S, the resonance frequency shifted from 1250 Hz (SAC 0.87) to 800 Hz (SAC 0.83). By comparing between the results of 1T and 4S, it can be concluded that, the SAC of sateen structure is higher compared to the twill structure while maintaining the same filler.

Figure 19 shows SAC values of 2T and 5S at three different mounting conditions, rigid backing, 3 cm and 6 cm air gaps. It is demonstrated from the figures that, the presence of an air gap between the sample and the back plate of the impedance tube, improved the SAC significantly. In another meaning, the averages of SAC of 2T at rigid backing, 3 cm and 6 cm in the frequency range from 100 Hz to 1600 Hz are 0.07, 0.32 and 0.4 respectively. Also for 5S sample, the averages of SAC are 0.06, 0.29 and 0.38 for rigid backing, 3 cm and 6 cm correspondingly.

Figure 19.

Blended filler (50% Styrofoam balls/50% Banana fibers).

Furthermore, by increasing the air gap from 3 cm to 6 cm, the resonance frequency in case of 2T shifted from 1600 Hz (SAC 0.87) to 1000 Hz (SAC 0.83) which enhanced the sound absorption at low frequency. And in the case of 5S, the resonance frequency shifted from 1600 Hz (SAC 0.84) to 1000 Hz (SAC 0.8). By comparing between the results of 2T and 5S, it can be concluded that, the SAC of twill structure is higher than the sateen structure.

Figure 20 displays the SAC of 3T and 6S at three different mounting conditions, rigid backing, 3 cm and 6 cm air gaps. It is demonstrated from the figures that, leaving an air gap between the sample and the back plate of the tube, improved the SAC significantly. In other words, the averages of SAC of 3T at rigid backing, 3 cm and 6 cm in the frequency range from 100 Hz to 1600 Hz are 0.05, 0.29 and 0.41 respectively. Also for 6S sample, the averages of SAC are 0.04, 0.27 and 0.4 for rigid backing, 3 cm and 6 cm correspondingly.

Figure 20.

100% Banana fibers filler with twill and sateen structures.

Moreover, by increasing the air gap from 3 cm to 6 cm, the resonance frequency in case of 3T shifted from 1600 Hz (SAC 0.88) to 1000 Hz (SAC 0.87) which enhanced the sound absorption at low frequency. And in the case of 6S, the resonance frequency shifted from 1600 Hz (SAC 0.85) to 1000 Hz (SAC 0.85). By comparing between the results of 3T and 6S, it can be concluded that, the SAC of twill structure is higher than the sateen structure.

Effect of type of filler on SAC at rigid backing condition

Figure 21 displays the SAC values of four different filling conditions at rigid backing; without filler, 100% mini Styrofoam balls, 50% mini Styrofoam balls and 50% Banana fibers, and 100% Banana fibers with twill and sateen structure. It is demonstrated from Figure 21(a), adding filler in twill structure improved the SAC significantly. In other words, the averages of SAC of 2T12, 1T, 2T and 3T in the frequency range from 500 Hz to 6300 Hz are 0.32, 0.42, 0.43 and 0.38 respectively. These results mean that, the combination between Styrofoam balls and banana fibers is the best absorbing material as filler with twill structure. In addition, by adding this filler in case of 2T, the resonance frequency shifted from 6300 Hz (SAC 0.93) to 4000 Hz (SAC 0.93) compared to 2T12 (without filler).

Figure 21.

Comparison of different fillers in twill and sateen structure.

Moreover, it is revealed from Figure 21(b), altering the type of filler in sateen structure enhanced the SAC significantly. In other meaning, the averages of SAC of 2S12, 4S, 5S and 6S in the frequency range from 500 Hz to 6300 Hz are 0.3, 0.39, 0.4 and 0.34 correspondingly. It can be concluded that, banana fibers is the best filler which enhanced the SAC with sateen structure.

Figure 22 depicts the effect of type of fillers on SAC, air permeability, thermal conductivity and thickness of fabric samples. The best sample of thermal insulation is (3T) due to its lower thermal conductivity which indicates to its availability to be as curtains, blankets or floor coverings. On the other hand, (2T) recorded (SAC 0.274) which means that it is considered as an absorbing material for sound waves.⁴² In other words, twill structure with a combination of 50% mini Styrofoam balls and 50% Banana fibers is suitable for thermal insulation applications in home furnishings. Banana fibers as a filler of twill fabric structure enhance the sound absorption performance.

Figure 22.

Effect of type of filler on fabric properties.

Radar chart according to the filler type at rigid backing condition

Table 15 and Figure 23 displays the radar chart areas and the rank of six samples which are filled with 100% mini Styrofoam balls, 50% mini Styrofoam balls and 50% Banana fibers, and 100% Banana fibers with twill and sateen structure as it was shown in Table 3. The rank of the fabric samples is according to higher value of air permeability, lower thickness, lower thermal conductivity and higher SAC to be applied in home furnishings such as curtains, pillows or blankets. By calculating radar chart areas, it was found that fabric sample (3T) recorded the first rank followed by (6S). Banana fibers are the optimal filler with twill and sateen structure to obtain the highest values of air permeability, lower thickness, higher thermal insulation and higher SAC.

Table 15.

Ranking of the radar chart area according the filler type.

Sample code	Air permeability (%)	Thickness (%)	Thermal conductivity (%)	SAC (%)	Radar chart area	Rank
1T	40	40	87	95	10,279	6^th
2T	68	48	82	100	13,868	3^rd
3T	99	100	100	74	22,293	1^st
4S	57	40	87	99	12,432	5^th
5S	74	42	73	91	12,479	4^th
6S	100	87	71	62	16,395	2^nd

Figure 23.

Radar chart area according to the filler type.

Conclusion

This paper aims to investigate the effect of fabric factors, air gap back the fabric samples in the impedance tube, different type of fillers on air permeability, thermal conductivity and sound absorption performance. Air permeability is negatively correlated to the thermal conductivity which means higher values of air permeability leads to higher thermal insulation. Fabric thickness is negatively correlated to thermal conductivity whereas lower thickness may guarantee more air molecules which make as barriers and thermal insulators. Sateen weave structure with single layer is suitable for curtains due to higher air permeability, lower thickness, higher thermal insulation and higher sound absorption.

On the other hand, by increasing the number of fabric layers of the optimal samples (T12 and S12), the values of SAC improved at low and high frequencies of sound waves. Moreover, by increasing the air gap between the back plate of the impedance tube and fabric samples, SAC values improved due to the presence of air molecules results in more friction with sound waves and higher sound attenuation. Banana fibers are the optimal fillers to form sound absorbing materials in home furnishing applications such as blankets or pillows.

In addition, the sewing direction and the type stitch recorded a significant effect on the sewing performance. Warp direction with twill fabric recorded higher sewing performance compared to the weft direction and sateen wave structure.

According the radar chart, for single layer, sateen weave structure with 12 picks per inch is the best sample of air permeability, thermal insulation and sound absorption. For multilayers of fabric, double layer of twill weave structure is the optimal sample of lower thickness, higher thermal insulation and higher sound absorption. The banana fibers 100% as filler with twill weave structure is the best sound absorbing material compared to the other fillers.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Wael A. Hashima

Manar Y. Abd El-Aziz

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Acoustic and thermal performance of home furnishings made of blended cotton-jute fabrics

Abstract

Keywords

Introduction

Materials and methods

Samples’ preparation

Testing and calculations

Results and discussion

Thermal and air permeability performance of home furnishings

Effect of fabric factors on air permeability

Effect of fabric factors on thermal conductivity

Effect of fabric factors on fabric thickness

Correlation between fabric thickness, air permeability and thermal conductivity

Ranking of fabric samples according to thickness, air permeability and thermal conductivity

Acoustic performance of single layers

Fabric factors affecting SAA

Radar chart areas of single layers of fabric

Acoustic performance of double and triple layers

Effect of the number of fabric layers on SAC

Effect of air gap of double and triple layers of fabric on SAC

Radar chart areas of double and triple layers of fabric

Effect of type of fillers on SAC

Effect of seam type and fabric structure on sewing performance

Effect of fabric factors on sewing performance

Ranking seam type according sewing performance by radar charts’ area

Effect of different types of fillers and air gaps on SAC

Effect of type of filler on SAC at rigid backing condition

Radar chart according to the filler type at rigid backing condition

Conclusion

Footnotes

Declaration of conflicting interests

Funding

ORCID iDs

References