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Abstract

In this research, a hollow spindle spinning machine was used to manufacture the multifunctional metal hybrid yarns with stainless steel wire (SSW) as core material, antibacterial nylon (AN) filaments and bamboo charcoal polyester filaments (BC-PETs) as inner and outer wrapped yarn, respectively. The wrapping numbers of produced metal hybrid yarns varied from 8.0 to 15.5 turns/cm. Furthermore, metal composite woven fabrics were fabricated with the metal hybrid yarns as weft yarns and PET filaments as warp yarns on a loom. These woven fabrics were evaluated in terms of far infrared (FIR) emissivity, anion density, electromagnetic shielding effectiveness (EMSE) and surface resistance. The antibacterial activity of the woven fabrics was assessed against both Staphylococcus aureus and Escherichia coli according two test methods AATCC100-2004 and 90-2011, respectively. The wrapping numbers showed a significant influence on the FIR emissivity and anion density of the produced woven fabrics. The presence of SSW in the hybrid yarns decreased the surface resistance and improved the EMSE of the woven fabrics. EMSE measurement showed that FH-15.5 woven fabrics with 0°/90°/0°/90° lamination angles displayed a better electromagnetic shielding behavior than with 0°/45°/90°/−45° lamination angles.

Keywords

Technical textile (fabric) research protective fabrics fiber yarn fabric formation and fabrication antibacterial activity electromagnetic shielding effectiveness

Introduction

The growth of electronic industry and the widespread use of electronic equipment in computations, communication, microwave oven, and other purposes have led to many electromagnetic interference (EMI) and radiation problems in electronic industry or daily life. To prevent EMI and electrostatic discharge, many researchers have developed metal composite fabrics with high conductivity and permeability as effective electromagnetic (EM) shielding and antistatic materials [1,2]. These metal composite fabrics have desirable properties such as flexibility, thermal expansion matching, EMI protection, and lightweight, etc. Lin and Low [3] fabricated conductive woven fabrics with stainless steel wire (SSW) based composite yarns which have core of polypropylene nonwoven selvedge (PPNS) and kevlar filament and sheath of SSW. Roh et al. [4] further developed conductive woven fabric from PET/Cu/PET or PET/SSW/PET covered yarns to arrest EM waves. Although these EM shielding textiles can protect humans from undesirable EM radiation, the functionality of such textiles is limited and difficult to meet other requirements such as healthcare, antibacterial, stable strength, durability wash and wear comfortable properties.

Bamboo charcoal polyester filaments (BC-PETs) have been widely applied in functional clothing because of their good far infrared (FIR) emissivity, anion release, and EM wave absorbance properties [5]. FIR rays, one type of infrared rays which have a wavelengths ranging from 4 to 14 µm and all living creatures on earth depend on them to live and grow. When FIR enters deep into the human dermis, molecular vibration is generated, thus heightening internal temperature. FIR can also accelerate cell metabolism and nutrient consumption. In addition, the BC-PET released anion can act on the parasympathetic nervous system to relax the nerves [6 –8]. Therefore, BC-PET has a good healthcare function for the human body.

EM shielding fabrics are excellent media for microorganism growth, particularly when used in hospitals or working environments with unhealthy indoor air quality [9]. Research on the antibacterial properties of metal composite fabrics is limited, and most studies refer only to the EM shielding characteristic. Hence, the primary objective of this study is to develop a multifunctional metal composite woven fabric that displays the desired electromagnetic shielding effectiveness (EMSE), FIR emissivity, and antibacterial activity. For the purpose of this study, bamboo charcoal/antibacterial/stainless steel metal hybrid yarns were produced with SSW as the core yarn, the antibacterial nylon (AN) yarn as the inner wrapped yarn, and BC-PET as outer wrapped yarn. The metal hybrid yarns were fabricated by using a hollow spindle spinning machine, and the wrapping amount varied from 8.0 to 15.5 turns/cm. SSW was selected mainly because of its high absorption and low reflection of EM waves compared to copper wire [10,11]. The metal hybrid yarns were then woven into fabrics as weft yarns on a loom with PET filaments acting as warp yarns. After the paper research, this study on the surface resistivity, FIR emission, anion release, EMSE, and the antibacterial properties for a multifunctional EMI shielding woven fabric is novel and has not been addressed in any other research papers.

Experimental

Materials

In this study, two types of functional yarns were used, namely, BC-PET and AN yarns. The AN yarns had been finished by organosilicon quaternary ammonium salt. BC-PET filaments were obtained from Hua Mao Co., Ltd. The BC content in the BC-PET filament is 1.2% and the particle size is 408.1 nm. The 50 µm SSWs were purchased from King Metal Fiber Technology Co., Ltd. The specifications of three materials are listed in Table 1.

Table 1.

Specifications of the yarns used to produce metal hybrid yarns.

Yarn type	Linear density (denier)	Diameter (mm)	Tenacity (cN/dtex)	Elongation (%)
BC-PET	150	0.301	3.520	16.24
AN	150	0.286	3.851	26.89
SSW	139	0.050	0.985	33.71

BC-PET: bamboo charcoal polyester yarn; AN: antibacterial nylon yarn; SSW: stainless steel wire.

Fabrication of metal hybrid yarns

Metal hybrid yarns were produced on a hollow spindle spinning machine. With a SSW as core material, the AN covered the SSW in the Z-direction (as inner wrapped yarn), and another BC-PET yarn covered the previous AN covered SSW in the S-direction (as outer wrapped yarn). Both the inner and outer wrapped yarns had the same wrapping amount at 8.0, 9.5, 11.0, 12.5, 14.0, and 15.5 turns/cm. Figure 1 shows the schematics of the metal hybrid yarn and product.

Figure 1.

Schematic of the metal hybrid yarns (a) and product (b).

Figure 2 displays the configuration and working principle of the hollow spindle spinning machine. AN and BC-PET yarns were preset on double-flanged packages C and F, respectively, and then placed over hollow spindles E and D, respectively. The hollow spindles were driven by a tangential belt from the motor. Furthermore, SSW was fed by input device A and dragged by winding roller K. When the hollow spindles rotated, the SSW was covered with AN and BC-PET yarns in the Z- and S-directions, respectively. After twisting, the multifunctional metal hybrid yarns were placed on winding roller K. The speeds of the two hollow spindles were both maintained at 8000 r/min and that of the winding roller was varied to control the wrapping amount of metal hybrid yarns. The characteristics of the produced metal hybrid yarns are presented in Table 2.

Figure 2.

Configuration of the hollow spindle spinning machine.

Table 2.

Characteristics of the metal hybrid yarns.

Yarn code	Linear density (D)	Wrapping amount (%)	Hybrid yarn constitutions
Yarn code	Linear density (D)	Wrapping amount (%)	Core	Inner wrapped yarn (Z-direction)	Outer wrapped yarn (S-direction)
H-8.0	449.9	8.0	SSW (27.8%)	AN (33.9%)	BC-PET (38.3%)
H-9.5	469.2	9.5	SSW (27.2%)	AN (38.2%)	BC-PET (34.6%)
H-11.0	479.0	11.0	SSW (25.0%)	AN (39.5%)	BC-PET (35.5%)
H-12.5	497.9	12.5	SSW (23.8%)	AN (40.1%)	BC-PET (36.1%)
H-14.0	511.5	14.0	SSW (22.9%)	AN (40.6%)	BC-PET (36.5%)
H-15.5	528.2	15.5	SSW (22.1%)	AN (41.1%)	BC-PET (36.8%)
BC-PET	150.0	Nil	BC-PET	Nil	Nil
PET	1000.0	Nil	PET	Nil	Nil

H-X: the metal hybrid yarns, where X is the wrapping amount; BC-PET: bamboo charcoal polyester yarn; AN: antibacterial nylon yarn.

Fabrication of metal composite woven fabrics

Metal composite fabrics were constructed in a plain weave on an automatic loom (SL7900, Taiwan). For the metal composite woven fabrics, the metal hybrid yarns and PET yarns (1000 D) were incorporated as weft and warp yarns, respectively. Figure 3 illustrates a 1/1 plain construction of metal composite woven fabric. Additional information on various woven fabrics is listed in Table 3.

Figure 3.

The illustration of metal composite fabric (wrapping amount of the weft yarn was 8 turns/cm).

Table 3.

Characteristics of metal composite fabrics.

Fabric code	Weft yarns	Warp yarns	Warp density (ends/cm)	Weft density (picks/cm)	Fabric weight (g/m²)	Metal content (g/m²)	Thickness (mm)
FH-8.0	H-8.0	PET	13.4	8.1	166.6	21.14	0.59
FH-9.5	H-9.5	PET	13.5	8.2	169.9	21.08	0.62
FH-11.0	H-11.0	PET	13.3	8.0	172.0	21.03	0.64
FH-12.5	H-12.5	PET	13.4	8.1	174.3	21.01	0.64
FH-14.0	H-14.0	PET	13.4	8.2	176.7	20.70	0.65
FH-15.5	H-15.5	PET	13.2	8.1	181.5	20.20	0.67
FBC-PET	BC-PET	PET	13.3	8.0	104.2	0	0.67
FPET	PET	PET	13.6	8.0	184.8	0	0.66

FH-X: the metal composite woven fabrics composed of weft yarns generated from H-X; FBC-PET and FPET correspond to the woven fabrics composed of BC-PET and PET weft yarns, respectively.

Testing methods

Before the measurements and tests, all fabric samples were conditioned in standard atmospheric conditions (20 ± 2℃, 65 ± 5% relative humidity) for 48 h. All tests were performed under standard ambient conditions.

EMSE measurement

Three methods are generally used to measure the plane wave SE of materials: the coaxial transmission line, shielding box, and free space transmission methods. In this study, the coaxial transmission line method was used to determine the EMSE of the conductive woven fabrics according to the ASTM D4935 standard [12]. In this research, the scan frequency varied from 300 kHz to 3 GHz and the EM field was a far-field plane wave. Figure 4 displays the configuration of the test set up used for assessing the EM shielding behavior of conductive fabrics. The EMSE of the test material was calculated by using the following equation [13,14]:

EMSE (dB) = 10 log \frac{p_{trans}}{p_{inc}}

(1)

where p_trans represents transmitted power and p_inc denotes incident power.

Figure 4.

Typical coaxial transmitter and sample holder (a); reference and load specimens (b) for the EMSE test. EMSE: electromagnetic shielding effectiveness, all dimensions above are in millimeters (mm).

Surface resistivity

Surface resistivity was measured according to JIS L1094. A specimen was placed on an electric insulating Teflon plate, and a 2.268 kg weight was laid on the tester to ensure that the probes had good contact with the surface of the specimen. Figure 5 displays the schematic of the RT-100 surface resistivity tester used in this study.

Figure 5.

Schematic of the surface resistivity tester.

FIR emissivity

A TSS-5X tester was used to measure the FIR emissivity as specified in FTTS-FA-010. The schematic of the FIR tester is presented in Figure 6. The FIR emissivity of each sample was tested 20 times in different positions to obtain the mean values.

Figure 6.

Configuration of the FIR tester. FIR: far infrared.

Figure 7.

Culture flasks used for the AATCC 100-2004 test method.

Anion density emissivity

The anion tester ITC-201 A was provided by Andes Technology Corporation (Japan). The specimen was cut into a 300 mm × 200 mm rectangle and then placed into a testing box to determine the anion density. The dimension of the testing box was 300 mm × 200 mm × 200 mm.

Assessment of antibacterial activity

Qualitative antibacterial test

A qualitative test of two test strains, namely, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was conducted in this study according to AATCC90-2011. All plates were examined for the inhibition zones after 24 h of incubation.

Quantitative bacterial reduction test

Antibacterial activity of the metal composite fabric was quantitatively evaluated based on AATCC 100-2004. Given the same strains (E. coli: 1.5 × 10⁵ cfu/mL and S. aureus: 1.5 × 10⁵ cfu/mL), the culture flasks were incubated for 24 h (Figure 7) followed by enumeration. Four swatches per jar were used to absorb the 1 ± 0.1 mL of inoculums according to AATCC 100-2004 test standard. The reduction of bacteria was calculated according to the following equation:

R % = \frac{B - A}{B} \times 100 %

(2)

where R is % reduction; A and B are the number of bacteria recovered from the inoculated treated test swatches in the jar incubated over the 24 h and 0 contact time, respectively.

Tensile strength and elongation at break

The tensile strength and elongation at break tests were performed according to ASTM D5034-5. The size of the samples was 10 cm × 15 cm, and the samples were measured at a speed of 30 cm/min.

Results and discussions

The physical properties of metal composite fabrics are presented in Table 4. Despite the difference in wrapping amount, the woven fabrics made from metal hybrid yarns (as weft yarns) displayed almost similar tensile strength in the warp direction. However, the tensile strength of the woven fabrics decreased along the weft direction with the increasing wrapping amount of the hybrid yarns. The six types of woven fabrics had similar wrap and weft densities, and only the hybrid yarns as weft yarns differed with different wrapping amount (Table 2). Hence, the tensile strength along the weft direction was related to the wrapping amount of hybrid yarns. Among these metal composite fabrics, the FH-8 fabric possessed the highest tensile strength, whereas FH-15.5 fabric displayed the lowest. This result was attributed to the high wrapping amount generating large wrapping angles in the outer wrapped yarns and reducing the cohesion of hybrid yarns. The produced metal composite fabrics displayed almost similar tensile strengths in the warp direction because the strength of PET is stable.

Table 4.

Physical properties of metal composite fabrics.

Fabric code	Tensile strength (N)		Tensile strain (%)
Fabric code	Weft-wise	Warp-wise	Weft-wise	Warp-wise
FH-8.0	591.2	855.9	158.4	105.2
FH-9.5	495.6	845.2	162.5	100.9
FH-11.0	455.1	848.7	176.1	102.7
FH-12.5	423.4	850.3	186.4	104.1
FH-14.0	392.3	860.4	203.1	107.5
FH-15.5	371.8	856.7	174.1	105.7
FBC-PET	297.0	860.4	90.1	103.7
FPET	857.2	854.9	102.3	105.6

FH-X: the metal composite woven fabrics composed of weft yarns generated from H-X; FBC-PET and FPET correspond to the woven fabrics composed of BC-PET and PET weft yarns, respectively.

To determine the relationship of the tensile strength of woven fabric and the wrapping amount of hybrid yarns in the weft direction, a relation curve is shown in Figure 8. The tensile strength decreased with wrapping amount of the hybrid yarns in the weft direction, as expressed by the following equation:

Y = - 41.05 X + 598.3

(3)

where Y is tensile strength in the weft direction (N); X is the wrapping amount of the hybrid yarns.

Figure 8.

Relationship between the tensile strength of the woven fabric and the wrapping amount of the hybrid yarns in the weft direction.

The correlation coefficient of the fitting line (R²) was 0.921, which indicates good quality of fit. The high values of the correlation index shows that the influence of wrapping amount of the metal hybrid yarns on the strength of the woven fabrics is large and have good statistically significant effects on the tensile strength.

FIR emissivity of the metal composite fabrics

All of the metal composite woven fabrics display the highest FIR emissivity with two layers (Table 5). This finding was ascribed to the too many layers of woven fabrics would prevent thermal transmission. For FIR release, woven fabrics must be heated or exposed to EM waves, thus generating energy in atoms and inducing electronic migration from the i = k to the i = L orbit. When the excited electron returned to its initial orbit (i = k) from i = L, an FIR wave was released at a wavelength roughly ranging from 4 to 14 µm. This wave could be detected by the FIR tester. Therefore, excessive fabric layers would prevent heat transfer from the bottom of the laminated fabrics to the surface. Jia et al. also Lin et al. [15] obtained a similar result.

Table 5.

FIR emissivity of FPET, FBC-PET, and FH-X series.

Lamination amount	F-PET	FBC-K	FH-8	FH-9.5	FH-11	FH-12.5	FH-14	FH-15.5
1	0.86 ± 0.02	0.87 ± 0.02	0.92 ± 0.01	0.93 ± 0.01	0.93 ± 0.01	0.94 ± 0.03	0.94 ± 0.02	0.95 ± 0.01
2	0.88 ± 0.01	0.89 ± 0.01	0.93 ± 0.01	0.94 ± 0.01	0.94 ± 0.02	0.95 ± 0.02	0.95 ± 0.07	0.95 ± 0.02
3	0.87 ± 0.01	0.88 ± 0.01	0.92 ± 0.01	0.92 ± 0.02	0.93 ± 0.03	0.93 ± 0.03	0.93 ± 0.01	0.93 ± 0.03
4	0.87 ± 0.02	0.88 ± 0.02	0.91 ± 0.02	0.91 ± 0.01	0.91 ± 0.01	0.92 ± 0.01	0.92 ± 0.02	0.92 ± 0.02
5	0.86 ± 0.14	0.87 ± 0.01	0.87 ± 0.02	0.88 ± 0.01	0.88 ± 0.03	0.88 ± 0.03	0.89 ± 0.01	0.93 ± 0.01
6	0.85 ± 0.01	0.87 ± 0.01	0.87 ± 0.01	0.87 ± 0.07	0.88 ± 0.02	0.87 ± 0.02	0.89 ± 0.03	0.90 ± 0.02

FH-X: the metal composite woven fabrics composed of weft yarns generated from H-X; FBC-PET and FPET correspond to the woven fabrics composed of BC-PET and PET weft yarns, respectively. The unit of anion density is ions/cm³.

The FIR emissivity of the FH-X series was higher than the FIR emissivity of F-PET and FBC-K; moreover, the FIR emissivity of the FH-X series increases with the wrapping amount of hybrid yarns. These results were attributed to the high wrapping amount, which indicates the high quantity of BC-PET yarns in the woven fabrics. It was found that when the wrapping amount of the hybrid yarns was 15.5 turns/cm with two layers of lamination, the FH-15.5 fabric exhibited the highest FIR emissivity among the tested woven fabrics.

Anion density of the metal composite fabrics

Table 6 presents the anion density of woven fabrics made from different metal hybrid yarns. The anion density increased with increasing wrapping amount of the hybrid yarns. In particular, the optimum anion density 497 ions/cm³ was obtained when the wrapping amount was 15.5 turns/cm. With increasing lamination amount, the anion density changed slightly relative to the single-layer woven fabric. This finding might be ascribed to the unchanging surface area of the laminated fabrics. Anions can act on the parasympathetic nervous system and relax the nerves [16]; therefore, the produced woven fabrics possesses healthcare and heat preservation functions. FH-15.5 exhibited the highest infrared emissivity and anion release capability among the woven fabrics because of the highest BC-PET yarn content.

Table 6.

Anion density of the FBC-PET and FH-X series.

Lamination amount	FBC-PET	FH-8	FH-9.5	FH-11	FH-12.5	FH-14	FH-15.5
1	368 ± 5.8	412 ± 12.5	435 ± 8.6	446 ± 11.6	461 ± 14.7	478 ± 8.1	497 ± 15.8
2	380 ± 6.3	431 ± 10.8	447 ± 12.8	459 ± 7.4	471 ± 10.3	491 ± 12.4	513 ± 14.4
3	384 ± 10.9	446 ± 8.9	450 ± 20.6	465 ± 24.8	473 ± 15.6	494 ± 18.3	516 ± 25.6
4	385 ± 8.2	451 ± 20.3	454 ± 13.1	469 ± 20.6	476 ± 9.1	495 ± 22.3	520 ± 23.8
5	387 ± 6.9	460 ± 9.1	458 ± 8.8	470 ± 16.7	478 ± 13.8	498 ± 17.3	521 ± 9.1
6	388 ± 7.4	464 ± 7.8	460 ± 9.7	472 ± 15.9	478 ± 12.9	499 ± 15.6	521 ± 8.7

FH-X: the metal composite woven fabrics composed of weft yarns generated from H-X; FBC-PET: the woven fabrics composed of BC-PET weft yarns.

EMSE of the metal composite fabrics

Figure 9 shows the variation in the EMSE of metal composite woven fabrics in the frequency range of 300 kHz to 3 GHz. From Figure 9, it was found that the EMSE of the FH-X series was higher than that of the FBC-PET woven fabrics. This result was attributed to the presence of SSW in the hybrid yarns. The overall evaluation of the EMSE of the FBC-PET fabric was almost zero in this frequency range mainly because most polymer composites were electrically insulated and transparent to the EM radiation. The FH-X series displayed a similar EMSE level to that of the fabric fabricated with metal composites, which possesses similar weft density and almost identical metal content (Table 2). The maximum EM shielding of 99.9% (−30 dB mark) was obtained at 470 MHz. However, the EMSE of the fabrics in the FH-X series was almost all less than −10 dB at high incident frequency. This finding is attributed to the ease of the high-frequency wave in penetrating the pores of the woven fabrics because of its short wavelength and high energy [17].

Figure 9.

EMSE of FBC-PET and FH-X series. EMSE: electromagnetic shielding effectiveness; FBC-PET: the woven fabrics composed of bamboo charcoal polyester yarn weft yarns.

To address many of the practical EMI problems as protective clothing, the conductive fabrics should provide at least −20 dB reduction across a wide range of frequencies [1]. When the weft yarn is composed of SSW only, the metal hybrid yarns cannot form a conductive grid with PET filament (warp yarn); thus, conductivity is unstable. As a result, high-frequency EM waves easily penetrate the produced single-layer woven fabric.

Effect of lamination angles and amounts on EMSE

To enhance the EMSE of the woven fabric further, the lamination method described by Chen et al. [18] was used. Figure 10 displays a schematic of the lamination method at 0°/45°/90° lamination angles. To investigate the effect of lamination angles and amounts on EMSE levels, lamination processing was performed using fabric FH-15.5 as a representative.

Figure 10.

Schematic of three-layer woven fabrics at 0°/45°/90° lamination angles.

Figure 11 presents the EMSE levels of FH-15.5 woven fabrics with different lamination amounts and angles. Metal composite fabrics with 90° lamination angles had the optimal EMSE, whereas fabrics with 0° lamination angles showed the worst performance. This phenomenon was attributed to only when the conductive metal wire formed grid inside the fabric or lamination fabrics, the fabrics would display the best EM shielding behavior, especially for the high-frequency EM waves. According to the study by Roh et al. [4], it also confirmed the metal grid was the most effective method to block EM waves. In this study, the SE would reach up to −30 dB when the lamination angles were kept with 90° interval, and the lamination amount were only two layers within a wide frequency range of 1.3–3 GHz. In this research, the EMSE of −30 dB was obtained within the high-frequency range of 1.3–3 GHz when four-layer metal composite fabric FH-15.5 at 0°/90°/0°/90° lamination angles. Therefore, varying the lamination angles is an effective method to improve EM shielding behavior of the metal composite fabrics.

Figure 11.

EMSE of the FH-15.5 series. The lamination amount varies from one to four layers, and the lamination angles are (a) 0°/0°/0°/0°, (b) 0°/45°/90°/−45°, and (c) 0°/90°/0°/90°. EMSE: electromagnetic shielding effectiveness.

Figure 12.

Surface resistivity of FH-X series.

Effect of the wrapping amount of hybrid yarns on surface resistivity levels

The surface resistivity of the FH-X series was significantly lower in the weft direction than in the warp direction (Figure 12). This result was ascribed to the use of the metal hybrid yarns as weft yarns, which contains the electrical conductor SSW. Surface resistance was also related to the wrapping amount of the metal hybrid yarns. High wrapping amount resulted in high surface resistance levels because additional wraps in outer wrapped yarns reduced the probability of SSW exposure on the surface of the hybrids yarns. Therefore, making contact with the SSW was difficult for the probe of the surface resistivity tester. The surface resistivity of conductive fabrics can be classified as follows based on AATCC-76-82: (1) conductive materials (<10⁵ ohms/square); (2) antistatic materials (ranging from 10⁵ ohms/square to 10¹² ohms/square); (3) insulating materials (>10¹² ohms/square). In summary, these conductive woven fabrics displayed satisfactory antistatic property, particularly in the weft direction.

Antibacterial activity evaluation

Qualitative assessment of the metal composite fabrics

The inhibition zones of the FH-15.5 fabric were determined on the plates after 24 h of incubation with two test strains, namely, E. coli and S. aureus, according to AATCC-90-2011 (Figure 13). The inhibition zone of S. aureus is larger than the inhibition zone of the E. coli bacteria. On the basis of the inhibition zones, we concluded that the antibacterial agent composed of quaternary ammonium salt showed a satisfactory migration property and antibacterial activity.

Figure 13.

Inhibition zones of the FH-15.5 fabric (a) E. coli and (b) S. aureus.

Quantitative evaluation of the metal composite fabrics

The antibacterial activity of the FH-15.5 fabric was quantitatively evaluated according to AATCC 100-2004. The results showed that E. coli and S. aureus were reduced by 80% and 85%, respectively. Although the PET warp yarns of the woven fabric did not exhibit antibacterial activity, the reduction percentages of E. coli and S. aureus were more than 80%.This finding could be attributed to the high antibacterial activity of quaternary ammonium salt. These antibacterial agents act against microorganisms by interacting with the cell membrane, thus deactivating proteins. These agents also affect the DNA molecules of the bacteria and reduce their capabilities to replicate and transfer, thus causing bacterial death [19,20].

Conclusions

In this research, we fabricated metal hybrid yarns by using the hollow spindle-spinning system. These hybrid yarns were then woven into fabrics as weft yarns on a loom. With the increasing wrapping amount of the hybrid yarns, the woven fabrics displayed improved FIR emissivity and anion release capability; however, the tensile strength of the woven fabric linearly decreased in relation to the wrapping amount of the hybrid yarns in the weft direction. FIR emissivity increased as the lamination amount in the FH-X woven fabrics increased from one layer to two layers. Nevertheless this emissivity decreased when the lamination amount of woven fabrics exceeded two layers.

The EMSE of the FH-15.5 woven fabric with four lamination layers and 0°/90°/0°/90° angles was better than those of the fabrics with 0°/45°/90°/−45° and 0°/0°/0°/0° lamination angles. The EMSE would reach to −30 dB within the wide frequency range of 1.3–3 GHz.

Fabric FH-15.5 displayed satisfactory antibacterial activity against both E. coli and S. aureus because of the presence of AN yarns. These metal composite woven fabrics with conductive properties may be used in protective clothing in hospitals or in working environments with unhealthy indoor air quality to protect humans from EM radiation and bacterial cross-infection. Moreover, these produced woven fabrics also can be used as EMI shielding case, protecting wall material, and packing materials in terms of industrial applications. Further studies will be carried out to investigate the comfort related properties such as drying capability, wicking behavior, and air permeability properties.

Footnotes

Acknowledgments

The authors are also grateful to the Laboratory of Fiber Application and Manufacturing, Feng Chia University, for providing research materials and laboratory equipment.

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) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Chinese Nature Science Foundation (No. 51343002), Key Discipline Project of Liaoning Province Universities (No. 2012310), and Project of Functional Textile Materials Laboratory of Eastern Liaoning University and National Science Council of the Taiwan, for financially supporting this research under Contract NSC-103-2221-E-035-028.

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. New approach to impart antibacterial effect and improve ink jet printing properties with modified SiO2 sols cationic biocides. Colloid Surf A Physicochem Eng Asp 2010; 361: 51–55.

Antibacterial properties and electrical characteristics of multifunctional metal composite fabrics

Abstract

Keywords

Introduction

Experimental

Materials

Fabrication of metal hybrid yarns

Fabrication of metal composite woven fabrics

Testing methods

EMSE measurement

Surface resistivity

FIR emissivity

Anion density emissivity

Assessment of antibacterial activity

Qualitative antibacterial test

Quantitative bacterial reduction test

Tensile strength and elongation at break

Results and discussions

FIR emissivity of the metal composite fabrics

Anion density of the metal composite fabrics

EMSE of the metal composite fabrics

Effect of lamination angles and amounts on EMSE

Effect of the wrapping amount of hybrid yarns on surface resistivity levels

Antibacterial activity evaluation

Qualitative assessment of the metal composite fabrics

Quantitative evaluation of the metal composite fabrics

Conclusions

Footnotes

Acknowledgments

Declaration of Conflicting Interests

Funding

References