Circular textiles: Transforming post-consumer garment waste into mat for bag production

Abstract

The growing population, better living conditions, fast fashion, and shorter life of garments are causing more textile waste. Post-consumer garment waste (PCGW) is now a major threat to the environment and human health, making recycling essential for circular economy and sustainability. In this study, PCGW was mechanically recycled into fibers, which were mixed with polyester fibers to make carding webs using a blow room-integrated carding machine, and then it was heat-pressed. One, two, and four layers of carding webs were used to make the four different types of mats. Morphological analysis, tensile properties, moisture management properties, and fourier transform infrared spectroscopy (FTIR) were used to characterize the developed mats to confirm its potential for the desired application. Among all the developed mats, four-layer-based mat exhibited the highest breaking force and elongation which is (29.12 ± 0.79) N, at extension 23.96%. The scanning electron microscopy (SEM) images showed the good arrangement of fibers in the mat with average fiber diameter (13.79 ± 0.73) µm. A moisture management test (MMT) confirms it can resist water to some extent with bottom surface wetting time slower than top (10.296 s). Also, one-way transport capacity was found to be 798.676. For the feasibility study, the produced mat was also used to make a bag. This paper contributes to the advancement of circular textiles by offering a new approach that converts PCGW into usable products like bags, demonstrating the commercial and environmental viability of textile recycling.

Introduction

Garment consumers primarily follow a linear business model, acquiring, using, and eventually discarding the used garments. ¹ Since the majority of garments are disposed of in landfills or burned, they pose an increasing environmental risk. ² The environmental impact of post-consumer garment waste (PCGW) is a major concern within the textile value chain. The European Union produces more than 5.8 million tons of PCGW in a year. ³ Post-consumer garment waste in Florida increased by 24.8% from 80.9 pounds in 2014 to 101.0 pounds in 2019. ⁴ Around 92 million tons of waste are produced each year as a result of the textile industry, with almost 50% of this waste coming from post-consumer use. ⁵ It is crucial to transition from a linear business model to a circular economy. Circular economy is an economic model that emphasizes the continual use of resources, aiming to maximize the lifespan of materials while decreasing waste generation. Besides that, it enhances 12 recycling efforts in line with the sustainable development goals (SDG) which include objectives aimed at sustainable consumption and production. ⁶ Reducing PCGW and its negative effects on the environment would require improvements in recycling technology and the promotion of circular textiles. ⁷

Recycling processes of PCGW include transforming apparel into fibers that can be used for new textiles, upholstery, or insulation. There are numerous studies done by some researchers of the recycling of garments. Arafat and Uddin developed (10–20 Ne) yarn and then successfully produced fabric for denim towels and home furnishing textiles from PCGW by mechanical recycling and ring spinning methods.^8,9 Although it was possible to use up to 25% recycled cotton fiber, performance beyond this limit was not investigated. Wazna et al. ¹⁰ worked with PCGW and produced thermal insulating non-woven material following the needle punching method. However, this study focused on thermal insulation performance, moisture management performance evaluation for more alternative applications. Lacoste et al. ¹¹ investigated with PCGW to produce bio-composite using the hand lay-up technique. The bio-composites’ limited mechanical performance (0.84 MPa bending, 0.44 MPa compression) restricts them to non-load-bearing uses like panels or internal insulation. Beton et al. ¹² manufactured fiber for cloth by cutting, shredding, and carding using PCGW.

However, several studies focus on mechanical recycling, needle punching, ring spinning methods for PCGW. Mechanical recycling processes include cutter machines, crushing machines (seven stages), and baling machines to convert the PCGW into fibers. ¹³ Converted fibers then are used in blow room, carding, drawing (two stages), roving, ring, winding, weaving/knitting, pre-treatment, dyeing, finishing, and garment manufacturing to make a cloth.^14,15 Chauhan et al. ¹⁶ used a needle punching method to develop non-woven fabric that needed multiple high-energy steps such as needling, singeing, and calendaring under high heat and pressure. These post-treatment stages needed a large amount of energy and thus cost more.

The textile business now uses this lengthy procedure. These process require further processes after producing carding webs for use as a carrier bags in other applications. Moreover, the techniques of converting the PCGW into mats for bag production had a limit focused in the earlier literature.

In this study, 100% cotton of PCGW (without any chemical treatment) was converted into fibers by a mechanical process. This study utilizes a carding stage, removing the need for post-treatment processing as prior works are needed. So, this makes it a more time efficient method compared to earlier approaches. This study explores the viability of developing mats from polyester and recycled PCGW fibers and also assesses the mat’s performance, quality, and possible advantages. Mechanical properties, moisture management properties, and morphological analysis were investigated.

Materials

The mats were developed using PCGW and polyester fibers. The PCGW was collected from a local area of Gazipur, Bangladesh, and polyester fibers were sourced from a local industry in Gazipur, Bangladesh, as well.

Methodology

Fiber preparation

Cutting and crushing were the main two steps in the conversion of fibers from PCGW. These processes helped to break down the garments into smaller pieces or fibers that were further processed for recycling or reuse. Figure 1 depicts the process diagram for preparing fibers from PCGW.

Figure 1.

Schematic diagram for transforming the PCGW into fibers.

First, the PCGW was manually cleaned of contaminants such buttons, zippers, labels, hooks, etc. After that, the garments were washed using a household detergent in warm water to remove any stains, dirt or residue chemicals. After that, they were air-dried for 24 h under ambient conditions. Once dried, scissors were used to cut the garments into small pieces. Small pieces of PCGW were fed into fabric cutter machine (Perfect Equipment pvt. ltd, India). To guarantee that each piece of fabric was 1 inch in size, it was cut four times. The result was shredded textile waste, frequently in the shape of tiny pieces or strips of fabric. To convert the tiny fabric strips into fibers, seven crashing beater machines (Perfect Equipment PVT LTD, India) were utilized. A trial-and-error approach was adopted to optimize the parameters of different crushing machine setups. Crushing module 1 had a feed roller speed of 100 rpm, a beater speed of 550 rpm, and a gauge length (the distance between the feed roller and beater wire) of 1.01 mm. Crushing module 2 maintained its gauge length at 0.762 mm, its feed roller speed at 90 rpm, and its beater speed at 550 rpm. Crushing module 3 operated at 500 rpm beater speed, 90 rpm feed roller speed, and a 0.508 mm gauge length. Crashing module 4 ran with beater speed at 450 rpm, with a 0.508 mm gauge length and a feed roller speed of 90 rpm. Crashing module 5 ran with a beater speed of 400 rpm, a feed roller speed of 90 rpm, and a 0.508 mm gauge. Crashing module 6 worked at 350 rpm beater speed, 90 rpm feed roller speed, and a gauge length of 0.381 mm. Lastly, crushing module 7 operated at a beater speed of 300 rpm, a feed roller speed of 90 rpm, and a gauge length of 0.254 mm.

Table 1 displays the characteristics of the recycled PCGW fibers along with polyester. The average value of 10 tests was recorded in the case of fiber length, thickness, fineness, and strength measurement of the samples.

Table 1.

Properties of PCGW and polyester fibers.

Type of fiber	Parameter	Value
PCGW fiber	Length (mm)	19.00 ± 0.98
	Fineness (micron)	4.47 ± 0.50
Polyester fiber	Cut length (mm)	37 ± 0.10
	Fineness (denier)	1.4 ± 0.04

Development of mat

The PCGW and polyester fibers were manually blended in a 50:50 ratio on the basis of weight. The prepared fiber mixture of PCGW and polyester was processed using an integrated blowing and carding machine (Jiangyin Tongyuan Textile Machinery Co., Ltd, China model: DSBL). It is to be mentioned here that it was not feasible to process 100% of the PCGW fibers using an integrated blowing carding machine because of the extremely low fiber length and significant short fiber content of PCGW. To ensure the smooth operation of the carding machine, virgin polyester fibers were combined with recycled PCGW fibers. Moreover, polyester fibers acts as a matrix and can aid in thermally bonding reinforced mats, potentially producing a more robust and durable fiber-to-fiber adhesion that is beneficial for the intended application. ¹⁷

The carding webs were cut into the desired size and placed between the two plates of the compression molding machine (CARVER Inc. USA Model:3891.4EN1000). The card web was compressed and consolidated at this point to create a mat. Three minutes, 220°C, and 5.5 tons of loads were the precise conditions for the molding process to take place. The schematic diagram of mat development process is shown in Figure 2. The four types of PCGW fibers reinforced mats were made from one, two, and four layers of carding webs. The mat made from layers of four-carding web was hand-cut and sewn to produce a prototype bag.

Figure 2.

Schematic diagram for the PCGW fibers reinforced mat production process.

Characterization

Three samples were tested for each test for better accuracy of the test result. Fiber properties were examined using fiber testing instruments (FCS, textechno, Germany) according to ASTM D 1447-00. The morphological analysis was assessed using SEM (Phenom Pro, Netherlands). A portable digital microscope (Jiusion, China) was also used to capture the images. Surface roughness was measured by ImageJ software using the image of the sample. ¹⁸ Thickness was measured using a digital portable thickness gauge meter (TG06-2011, China) according to ASTM D1777. The chemical structures of developed samples were investigated by FTIR (4600LE, Jasco, Japan) following the ASTM E168 method. The breaking force and percentage extension at break of the developed sample were measured using a universal strength tester (Testometric M250-3CT) in accordance with ASTM D5034. The analysis of moisture management properties was carried out with a moisture management tester (M-290, SDL, Atlas) in compliance with the AATCC 195-2009 standard.

Results and discussion

Morphological analysis

Mat formation occurred by the thermal fusion of polyester fiber, which softened at 220°C. The soft fibers melt and flow around the recycled PCGW fibers, thereby causing inter-fiber adhesion to occur. When the mat cools down, polyester fibers solidify and create strong physical bonds with the PCGW fibers. Three samples were developed depending on the number of carding web layers and their thickness, with the standard deviation provided in Table 2.

Table 2.

Thickness of developed PCGW fibers reinforced mats.

Sample	Thickness (mm)
Single layer	0.22 ± 0.009
Double layers	0.26 ± 0.006
Four layers	0.76 ± 0.004

SEM analysis enables the examination of fiber organization, surface morphology, and homogeneous interfacial adhesion between recycled fibers and polyester fibers in the developed sample. ¹⁹ The comprehensive visual and structural analysis of the sample was performed by this investigation. An SEM and actual images of the sample are displayed in Figure 3. All fibers are attached in a random manner. An average fiber diameter of 13.79 ± 0.73 µm was found. The fiber to fiber gap was evaluated at 19.533%, which is suitable for insulators and shopping bags. ²⁰ Furthermore, a 3D surface topography image shows the surface roughness of the developed sample in Figure 3(c). This surface has lower heights of peaks. That shows the uniform surface of the developed PCGW fiber reinforced mats. Fiber packing is more compact, suggesting better compactness of fibers. The developed reinforced mat and reinforced mat-based bag are shown in Figure 4.

Figure 3.

SEM images of developed mat: (a) microscopic image (magnification 8×), (b) surface roughness, (c) fiber distribution, (d) fiber to fiber gap, and (e) diameter distribution of fibers.

Figure 4.

Actual image of developed PCGW fibers: (a) reinforced mat and (b) reinforced mat-based bag.

Mechanical properties

The force–elongation curve represents the relationship between the applied force on a material and the resulting elongation it undergoes. As the force increases, the material elongates, and the curve typically shows how the material deforms under stress until it eventually breaks. ²⁰ The shape of the curve provides insights into the material’s mechanical properties, such as elasticity, tensile strength, and ductility. The relation between force and elongation of the developed PCGW fibers reinforced mat is shown in Figure 5.

Figure 5.

Force–elongation curves of: (a) single, (b) double, and (c) four layers of web-based mat.

This curve helps in understanding the material’s breaking point, elongation, and tensile strength. Among the three samples, the highest breaking force of (29.12 ± 0.79) N was achieved from sample (c) at extension 23.96%, and the lowest breaking force of (3.41 ± 0.05) N was found in sample (a) at extension 8.646%. In the case of sample (b), maximum force was achieved at (7.69 ± 0.89) N. A higher number of layers contributed to the highest strength in the sample (c). The increased reinforced material improves the load bearing capacity and stress transfer, resulting better tensile strength. ²¹ Using same fiber content, the five-reinforced layer composite demonstrated 1.5 times more strength than the one with one reinforced layer. ²² Similarly, the lower amount of breaking force exhibited in sample (a) is due to the lower number of layers in the sample. The mat developed by Hinchliffe and his research team found tensile strength 26.08 N. ²³ Baccouch et al. used an alkaline (NaOH) treatment to increase the interfacial adhesion between cotton fibers (from textile waste) and epoxy matrix. Carding and needle punching were utilized to shape the treated fibers into mats, which were subsequently filled with epoxy. Treated sample showed approximately 11 N and untreated sample showed breaking load approximately 3.7 N. ²⁴ Another was study performed by Hussain where waste cotton fabrics were converted into mat by a needle punching method, where the highest tensile strength was 153.7 Pa. ²⁵ Another study utilized virgin and recycle polyester separately to evaluate the performed by a needle-punching method. Recycled fabrics demonstrated lower strength about 8–10% but 7–8% higher elongation with respect to virgin polyester. ¹⁶ Similarly, a study by Chauhan et al. evaluated the bursting strength of needle punched filter fabrics from recycle and virgin polyester. The results showed a similar trend in that recycled polyester had 3.584% less strength than virgin polyester. ²⁶ However, the needle punching method had less inter fiber bonding compared to the heat pressing method due to their weak mechanical bonding. From the observations, it is clear that the degree of layering in PCGW fibers reinforced mats directly affects their tensile strength, which improves durability by more evenly dispersing applied stress throughout the material. According to this curve, materials work well for light- to medium-duty usage, like insulators and shopping bags.

MMT analysis

MMT assesses a fabric’s capacity to control moisture by measuring how rapidly it absorbs, distributes, and moves moisture along its surfaces. ²⁷ Water location in the developed mat is shown in Figure 6.

Figure 6.

(a) Water location versus time diagram and (b) radar diagram of the mat.

There is a noticeable difference in the moisture behavior of the top and bottom surfaces, according to the MMT report for the developed mat. The top surface had a modest absorption rate of 4.1449%, yet may absorb moisture in 5 s after being wetted. In contrast, the bottom surface had a slower wetting time of 10.296 s but an absorption rate of 80%. With a maximum wetted radius of 6.0 mm and a spreading speed of 0.477 mm/s, the bottom surface of the fabric displayed restricted moisture spreading, while the top surface of the fabric displayed less spreading. The fabric’s one-way transport capacity value of 798.676 showed that it can transfer moisture from the upper surface to the lower surface. In the developed mats, the presence of polyester fibers partially hinders water penetration. Polyester has a low absorption rate and rapid initial wetting because of its natural hydrophobicity, which restricts water absorption on the top surface. ²⁸ The bottom surface, on the other hand, retains a lot more moisture, which explains its shorter wetting time and higher absorption rate. This surface is probably made up of loosely packed or more absorbent fibers. ²⁹

FTIR spectroscopy

FTIR spectroscopy uses an infrared light absorption measurement to identify and quantify chemical components. Every substance emits a distinct infrared spectrum with distinct absorption peaks that signify various molecular connections. The FTIR analysis of the developed mat is shown in Figure 7.

Figure 7.

FTIR report analysis of developed mat.

The peaks observed at 1711 cm⁻¹ were linked to the vibrations of the C=O (carbonyl) group in the polyester structure. Meanwhile, the peaks at 1013, 870, and 1200 cm⁻² are associated with the cyclic groups present within the polyester’s molecular structure. These specific peaks help in identifying the functional groups and structural elements characteristic of polyester. ³⁰

Cotton fiber’s FTIR spectrum reveals distinct peaks for cellulose, lignin, and hemicellulose. An important peak for hydroxyl groups is at 3330 cm⁻¹, C-H stretching is at 2896 cm⁻¹, CH₂ bending is at 1428 cm⁻¹, and β-glycoside links in cellulose are at 894 cm⁻¹. ³¹ In the developed mat, polyester fibers showed peaks at 1697 cm⁻¹, and 1100 cm⁻¹, 1241 cm⁻¹. The bond vibrations are at 1700 cm⁻¹ for -C=O, for the aromatic ring at 1200 cm⁻¹, and for O=C-O-C at 1100 cm⁻¹. ²⁸ In the developed sample, peaks at 3363 cm⁻¹, 2896 cm⁻¹, and 1032 cm⁻¹ were identified by FTIR analysis of cotton. The peak at 2896 cm⁻¹ is linked to the C-H stretching vibrations in cellulose and hemicellulose, whereas the peak at 3363 cm⁻¹ is related to the hydroxyl (OH) groups in cellulose, lignin, and water. Moreover, the polysaccharide stretching vibrations of (C-O) and (O-H) in cellulose are related to the peak at 1032 cm⁻¹. So, it is clear that cotton and polyester fibers are present in the prepared mat, and since one of the components of the developed sample is PCGW, there is a possibility of the presence of other materials as well.

Conclusion

This study explores the potential of circular textile innovation in addressing the growing problem of PCGW through the development of PCGW fiber reinforced mats for the production of bags or similar products. On average 19 mm length of PCGW fiber and 37 mm length of polyester fiber were utilized to develop the mat. From the study, the developed mats demonstrated good to intermediate breaking force and extensibility. The tensile test determined that an increasing number of layers improved the tensile strength properties. Four layered samples showed a breaking strength of 29.12 N whereas single layers demonstrated 3.41 N. Elongation for the four layered sample was 23.96% whereas it was 8.64% for a single layer. The moisture management properties of the mat revealed its ability to absorb moisture while exhibiting slight resistance. The inner surface absorbed 4.1449% moisture in 5 s, whereas the outer surface absorbed 80% moisture in 10.296 s. The fabric’s one-way transport capacity was found to be 798.676, showing that it can transfer moisture from the upper surface to the lower surface, which is suitable for the desired application. The FTIR test was employed to confirm the material composition of the mat, identifying the presence of polyester peaks observed at 1697 cm⁻¹, and 1100 cm⁻¹, 1241 cm⁻¹, and cotton compounds peaks at 3330 cm⁻¹, 2896 cm⁻¹, 1428 cm⁻¹, with the potential existence of other compounds from the varied post-consumer material. This research highlights the potential for recycled PCGW to be transformed into value-added products, like carrier bags, providing a sustainable alternative to traditional textile manufacturing processes. Future works can be focused on its commercial implications, long-term durability, and utilizing recycled polyester rather than virgin polyester or blends of garments to promote an eco-friendly approach.