PET Fibers Research Articles

Durability of non-woven geotextiles produced from recycled polyethylene terephthalate (PET)

Achieving the goals of sustainable development and circular economy requires recycling and reusing plastic materials. In this research, the durability of five needle-punched non-woven geotextiles were experimentally studied. The geotextiles were made of recycled PET (rPET), virgin PET (vPET), and combinations of rPET and vPET fibers. The samples were hydrolyzed for a period of 14, 28, and 56 days and the retained tensile strength and puncture resistance of the samples were determined at the end of each interval. Moreover, this study took the benefits from the capability of differential scanning calorimetry (DSC), Fourier transforms in infrared spectroscopy (FTIR) analysis, and scanning electron microscopy (SEM) images to interpret the results acquired. Testing on as-received products, it was understood that recycling process could increase crystallinity of the fibers, increasing the fibers fragility, reducing the tensile strength and elongation capacity of rPET fibers. Moreover, considering the borderline value of 50% retained strength, a shorter service life (up to 30%) of rPET products in comparison with vPET products, due to higher degradation rates, was observed.

Highly Filled Waste Polyester Fiber/Low-Density Polyethylene Composites with a Better Fiber Length Retention Fabricated by a Two-Rotor Continuous Mixer

A key challenge in the utilization of waste polyester fibers (PET fibers) is the development of fiber-reinforced composites with high filler content and the improvement of fiber length retention. Herein, the effects of a two-rotor continuous mixer and a twin-screw extruder on the structure and properties of waste polyester fiber composites were evaluated. The results revealed that the mechanical properties of the composites were improved significantly with increasing fiber content, especially when processed using the twin-rotor continuous mixer. This mixer facilitated the formation of a robust fiber network structure, leading to substantial enhancements in tensile strength, flexural strength, and heat resistance. Specifically, compared to those processed by the twin-screw extruder, with 60 wt% fibers content, the tensile and flexural strengths of specimens processed by the twin-rotor continuous mixer increase by 21% and 13%, respectively. The average fiber length in specimens processed by the twin-rotor continuous mixer was 32% longer than that in specimens processed by the twin-screw extruder, attributable to the lower shear frequency and the higher tensile ratio of the former. This blending technique emerges as an effective strategy, contributing significantly to promoting the development and practical application of waste textile fiber-reinforced polymer composites.

Synergistic ZnO-NiO composites for superior Fiber-Shaped Non-Enzymatic glucose sensing

The rise in diabetes requires new glucose sensors, as traditional enzyme-based and planar electrodes are sensitive to the environment and hard to integrate into wearables. This study addresses these issues by developing a flexible, non-enzymatic glucose sensor using a co-sputtered ZnO: NiO (NZ) composite on PET fiber. This design enhances the tensile strength (60 mm at 3.2 kg.f) and conductance (0.23 S) of Cu-coated PET fiber, forming a durable sensing platform. The electrode’s enhanced electrochemical surface area (0.13 cm2) offers abundant active sites for glucose interaction, while the synergistic interface effect boosts ion and charge transport, improving glucose sensing. The sensor achieves high sensitivity (28.96 mA·cm−2·mM−1), fast response time (23 s), and a low detection limit (0.25 mM), while maintaining 78 % of its sensitivity after 500 bending cycles. These features, combined with good electrochemical stability—retaining 60 % of its initial performance after prolonged electrolyte exposure—mark a significant advancement in wearable glucose monitoring.

High-performance ZnO:CuO composite-based fiber-shaped electrode for non-enzymatic glucose sensing in biological fluids

The growing diabetes epidemic necessitates new glucose sensors, as traditional enzyme-based and planar electrodes face limitations in environmental stability and seamless integration into wearable technology. This research tackles these issues by designing a flexible, enzyme-free glucose sensor utilizing a co-deposited ZnO:CuO (CZ) composite on PET monofilament. This approach improves the tensile strength (55 mm at 2.7 kg.f) and electrical conductance (0.32 S), of the Ni-coated PET fiber, resulting in a strong and reliable sensing platform. The electrode's enlarged electrochemical surface area (0.11 cm2), offer a high density of active sites for glucose interaction, and the synergistic interface significantly enhances both ion and charge mobility. This results in exceptional sensitivity (35.05 mA.cm−2.mM−1), a rapid response (24 s), and a low detection limit (0.15 mM). Durability tests demonstrate that the sensor retains 80% of its sensitivity after 500 bending cycles, making it well-suited for wearable applications. Furthermore, the sensor accurately detects glucose in biological samples, such as saliva, highlighting its potential for non-invasive, real-time glucose monitoring in wearable healthcare systems.

Crack-healing of cost-effective engineered cementitious composites reinforced by recycled selvage fiber

This paper presents the first experimental investigation of the crack-healing behavior of recycled selvage fiber-reinforced engineered cementitious composites (RSF-ECCs). Fly ash (FA), ground granulated blast-furnace slag (GGBS), and crumb rubber powder were utilized to fabricate greener ECCs. RSF was used as main reinforcement; it contains polyethylene (PE), glass (GS), and PET fibers. For overall mechanical properties, RSF-ECC incorporating GGBS (ECC-S-RSF) obtained a compressive strength of over 80 MPa and a tensile strain capacity of over 10%, values that are unprecedented in other recycled fiber-reinforced ECCs. Furthermore, the ECC-S-RSF showed the best cost efficiency among representative recycled and PE fiber-reinforced high-performance ECCs. In terms of the crack-healing performance, test results indicated that RSF-ECCs had excellent healing capacity in closing crack openings, and GGBS had a greater contribution to crack-healing than FA did. However, the stiffness and tensile restorations of RSF-ECCs were relatively modest compared to those of conventional ECCs. Calcium carbonate and C-S-H gel were dominant healing materials of RSF-ECCs.

Janus Structure Construction of Polyester-Cotton Fabrics for Achieving Excellent Moisture, Moisture-Permeability, and Antibacterial Capability.

Integration of hydrophobic and antibacterial functionalities into polyester-cotton blended (PTCO) textiles has attracted more attention but remains a challenge. Here, a Janus fabric with antibacterial effect, hydrophobicity, and enhanced moisture-permeability is fabricated using a "mist polymerization" approach. The PET fibers in the PTCO fabric are amino-functionalized through ammonolysis reactions of PET molecules with HDA, and mist treatments of poly lauryl methacrylate (PLMA) and poly(DMC-co-MA) (PDM) are applied on the two side surfaces of the PTCO-HDA fabric, respectively. The resulting Janus fabric exhibits an antibacterial rate of 99.9% against both E. coli and S. aureus, along with a hydrophobic property on its single side (PTCO-HDA@PLMA). Additionally, the establishment of a surface-free energy gradient across the fabric confers superior moisture-permeability to the Janus fabric, offering advantages in preserving textile comfort. Moreover, this approach does not significantly compromise the original fabric properties, such as mechanical strength, moisture permeability, and fabric softness. The proposed method offers a straightforward and scalable strategy for textile finishing, demonstrating great potential in expanding the application scope of PTCO fabrics, and it may hold a pivotal role in diverse applications, notably encompassing home textiles, wound dressings, and high-performance sportswear.

PET Glycolysis to BHET Efficiently Catalyzed by Stable and Recyclable Pd-Cu/γ-Al2O3.

Glycolysis of poly(ethylene terephthalate) (PET) is a prospective way for degradation of PET to its monomer bis(hydroxyethyl) terephthalate (BHET), providing the possibility for a permanent loop recycling. However, most reported glycolysis catalysts are homogeneous, making the catalyst difficult to recover and contaminating the products. Herein, we reported on the Pd-Cu/γ-Al2O3 catalyst and applied it in the glycolysis of PET as catalyst. The formed structure gave Pd-Cu/γ-Al2O3 a high active surface area, which enabled these micro-particles to work more efficiently. The PET conversion and BHET yield reached 99% and 86%, respectively, in the presence of 5 wt% of Pd-Cu/γ-Al2O3 catalyst within 80 min at 160 °C. After the reaction, the catalyst can be quickly separated by filtration, so it can be easily reused without significant loss of reactivity at least five times. Therefore, the Pd-Cu/γ-Al2O3 catalyst may contribute to an economically and environmentally improved large-scale recycling of PET fiber waste.

Effects of drawing stress on the molecular-chain extension in fiber structure formation of poly(ethylene terephthalate)

In the present study, the effects of drawing stress on poly(ethylene terephthalate) (PET)-chain extension prior to fiber-structure formation as well as the mechanical and thermomechanical properties of the resulting fiber were investigated. The amount, persistence length, and extension of molecular chains bearing external force were analyzed from the diffraction of the smectic phase observed after necking. For PET fiber with a molecular weight of 19,600 g/mol drawn at a stress lower than the critical value of 99 MPa, less d-spacing and less amount of the smectic phase, slower crystallization, and longer crystallization-induction time were observed. Furthermore, the critical stress value appeared to decrease with increasing molecular weight. When the drawing stress was less than the critical value, the d-spacing extrapolated immediately after necking decreased rapidly with decreasing drawing stress, and this decrease leads to a decrease in the tensile strength and thermal shrinkage of the drawn fiber.

Distribution of microplastics between ice and water in aquatic systems: The influence of particle properties, salinity and freshwater characteristics

Microplastics (MPs) are an anthropogenic emerging pollutant, with global contamination of both marine and freshwater systems extensively documented. The interplay of MP particle properties and environmental conditions needs to be understood in order to assess the environmental fate and evaluate mitigation measures. In cold climate, ice formation has appeared to significantly affect the distribution of MPs, but so far, limited research is available comparing different aquatic systems, especially freshwater. Experiments often rely on artificial water and specific MP model particles. This study used laboratory tests to investigate the ice-water distribution of a variety of environmentally relevant MP particle types (PP, PE, PS and PVC fragments (25–1000 μm), PET fibers (average length 821 μm, diameter 15 μm)) across different water types, including artificial water of high and low salinity, as well as natural water from a lake and a treatment wetland. Overall, ice entrapment of MPs occurred in almost all tests, but the ice-water distribution of MPs differed across the different water types tested. Among the tests with artificial water, salinity clearly increased MP concentrations in the ice, but it cannot be resolved whether this is caused by increased buoyancy, changes in ice structure, or thermohaline convection during freezing. In the natural freshwater tests, the partition of MPs was shifted towards the ice compared to what was seen in the artificial freshwater. The influence of different types of dissolved and particulate substances in the different waters on MPs fate should be considered important and further explored. In this study, the higher content of suspended solids in the lake water might have enhanced MP settling to the bottom and thereby contributed to the absence of MPs in the ice of the lake test, compared to the wetland test with low suspended solids and considerably more MPs in the ice. Furthermore, the higher negative charge in the lake water possibly stabilized the negatively charged MPs in suspension, and reduced ice entrapment. Regarding particle properties, shape had a distinct effect, with fibers being less likely incorporated into ice than fragments. No fibers were found in freshwater ice. However, it became clear that ice entrapment of MPs depends on factors other than the particles' buoyancy based on density differences and particle size and shape alone.

Experimental Modeling and Optimization of the Tribo-Electrostatic Separation of PET Fibers From End-of-Life Tires

Experimental Modeling and Optimization of the Tribo-Electrostatic Separation of PET Fibers From End-of-Life Tires

Optimising microplastics analysis for quantifying and identifying microplastic fibres in laundry wastewater

Current methods for measuring microplastic fibres (MPF) are cumbersome, time consuming and unscalable for routine high throughput analysis. This study reports a method for rapidly extracting, quantifying and analysing MPFs in laundry wastewater with several key improvements which vastly enhance overall efficiency and scalability of analysis. FT-IR surveying is employed as a preliminary step in analysis to quickly determine what polymers are present in a sample prior to fluorescence treatment. Using random quadrating, whole 25 mm filter membranes were surveyed in <30 min with high recovery rates. In industrial laundry wastewater samples, polyester was the most common MPF, however acrylic, nylon, cotton and rayon were all ubiquitous. The study also demonstrates that an excitation wavelength of 365 nm was optimal for fluorescing PET fibres like polyester which were stained with Nile Red, but not 495 nm, which is commonly used in microplastic analysis. Finally, a custom ImageJ macro was written to automatically enumerate and describe MPFs on filter membranes using just a single stitched fluorescence image. In just a few seconds, concentrations of up to 40,000 fibres/L were analysed in industrial laundry wastewater samples with a lower particle size limit of 20 μm. This study highlights the need for more optimised and scalable analysis workflows which maintain high levels of reliability and accuracy.

Synergistic effects of Bacillus subtilis and PET fiber additions on the mechanical properties of Alkali-Activated composite mortars

This study investigates the impact of Bacillus subtilis and PET fiber additions on the mechanical properties of alkali-activated composite mortars (AACMs). Blast furnace slag (BFS) is used as the primary binder, activated by sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Controlled curing conditions at 20 °C and 100 % relative humidity for 28 days were maintained. Comprehensive tests, including compressive strength, flexural strength, and scanning electron microscopy (SEM) analyses, were conducted. Results showed that AACMs incorporating Bacillus subtilis exhibited a 25 % increase in compressive strength and a 20 % increase in flexural strength compared to control samples. The addition of PET fibers further improved these properties by 10 % and 8 %, respectively. These findings highlight the potential of bio-enhanced alkali-activated materials in sustainable construction.

Use of commercial synthetic filament waste to reinforce biobased poly(butylene succinate) with the aid of compatibilizers

Since poly(butylene succinate) (PBS) has low rigidity for engineering application, this research attempted to reinforce PBS with poly(ethylene terephthalate) (PET) and polyamide-6 (nylon6) filaments with the reservation of polymer toughness. Filaments were chopped to be short fibers (length of 2 mm to 4 mm) and melt compounded with PBS pellets in the weight ratio of 1 wt%, 5 wt%, and 7 wt% using a twin-screw extruder that the temperature profile was set high enough for melting only PBS matrix. Two types of compatibilizers; hexamethylene diisocyanate (HMDI) or hexamethylene diamine (HMDA) of 0.05 wt% were used to treat fiber surface. It was found that tensile modulus of PBS increased with respect to fiber concentration, which untreated PET fibers provided higher tensile modulus about 2% to 7%. Surface treatment of fibers with either HMDI or HMDA increased rigidity of the composites, while elongation at break and impact strength were also improved with respect to fiber concentration. Also, shifting in glass transition temperature of PBS by DMA indicated improved interfacial interaction, which HMDA treatment gave the best benefit for mechanical properties. Number-average molecular weight of HMDI-treated composites was closed to extruded PBS, however, those of HMDA-treated composites were reduced dramatically implying chain scission highly occurred. SEM micrographs revealed good interfacial adhesion obtained after fiber treatment. Crystallization of PBS studied by XRD showed that the crystal form was not affected by the compatibilizer.

Utilization of poplar fibers in needle punched nonwovens

The focus of this study is to conduct pioneering research on utilizing poplar seed hair fibers in needle punched nonwovens. These fibers were blended with hollow PET fibers at two different weight ratios to obtain needle punched webs for the first time. The weight, thickness, abrasion resistance, bursting and tensile properties, hydrophobic/oleophilic surface characteristics of the nonwovens are analyzed elaborately. Finally, it has been demonstrated that poplar fiber-containing nonwovens have superior rose oil absorption compared to solely PET nonwoven fabrics. When compared the maximum adsorption capacities, the incorporation of 37.3 wt.% and 21.7 wt.% poplar fiber into PET nonwoven increased the oil absorption by approximately 35 and 24 times, respectively. Although pristine PET nonwoven was able to remove only 16% of MB dye from aqueous dye solution, addition of poplar fiber enhanced the removal process and the solution had been decolorized to nearly colorless. The results indicated that poplar blended nonwoven fabrics treated with NaClO2 show the high-performance removal of MB dye from wastewater, with the increased percentage of 40% and 67% for PET-PO30 and PET-PO60 fabric, respectively. Therefore, developing industrial scale surfaces with non-traditional and sustainable poplar seed fibers, marks a significant advancement for the textile industry.

Combined effect of fiber and degree of stabilization on the early age behavior of cement bound granular mixtures

Abstract An investigation has been undertaken to study the effect of fiber-reinforcement and different degrees of stabilization on the early age mechanical behavior of cement bound granular mixtures intended to be used as a base layer within pavement structure. Waste plastic fibers (WPF) recycled from soft drink bottles were used at 1% by the mass of aggregate to reinforce cemented mixtures. To stabilize different mixtures, cement content of 3%, 5%, and 7% by the mass of aggregate and by the weight of aggregate and fiber were used for conventional and fiber-reinforced cement bound granular mixture (CCBGM&amp; FRCBGM), respectively. The examined properties include unconfined compressive strength (UCS), indirect tensile strength (ITS), bulk density, and ultrasonic pulse velocity (UPV). The results showed a significant improvement in UCS and ITS as the cement amount increased for both types of mixtures. Incorporating PET fibers at cement content of 5% and 7% resulted in a noticeable improvement of ITS compared to the conventional mixtures while a marginal enhancement in the UCS occurred due to fiber-reinforcement. Both bulk density and UPV were increased as cement content increased, while both were decreased due to the inclusion of waste plastic fibers (WPF). Hence, utilizing waste plastic fiber has a positive and promising effect on the pavement structure from sustainability, integrity, and economic points of view.

Gamma‐ray‐induced modification of poly(ethylene terephthalate) and polypropylene solid materials with halogen‐containing olefins for X‐ray CT image contrast enhancement

AbstractIt is known that X‐ray CT of organic polymer materials usually provides low‐contrast images because of the low X‐ray absorption of these materials. In this paper, we describe a new method to enhance the contrast of X‐ray CT images of organic polymer materials. We demonstrate that gamma‐ray irradiation of poly (ethylene terephthalate) (PET) fibers in dichloromethane containing 2‐bromoethyl methacrylate, 2‐chloroethyl methacrylate, or 4‐bromostyrene results in the grafting of halogen‐containing oligomeric chains onto the PET fibers. Focused ion beam scanning electron microscopy (FIB‐SEM) and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) analyses revealed a homogeneous distribution of bromine atoms within the 2‐bromoethyl methacrylate‐modified PET fibers, not only on the surface. This uniform incorporation translated to a significant improvement in X‐ray CT image contrast compared with pristine fibers. Similar treatment of polypropylene pellets also enhanced the contrast of their X‐ray CT images. This is a new simple and effective method to enhance the X‐ray CT image contrast and potentially applicable to various polymer materials including polymer composites and porous polymer materials, readily allowing the observation of their 3D microstructures finely.

Effect of surfactants on enzymatic hydrolysis of PET

Enzyme is difficult to adsorb on the surface of high-crystallinity poly(ethylene terephthalate) fibers (PET，crystallinity of 48.56 %) due to the high hydrophobicity of PET fibers. Surfactants can effectively reduce the PET/water interface tension and improve the adsorption of enzyme on PET fibers, increasing the degradation of PET fibers promoted by enzyme. In this paper, different nonionic surfactants (Triton X-100, Triton X-114, Triton X-405, PEG 200, PEG 400, PEG 600, Tween 20, Tween 80) were selected to investigate the effect of surfactant on the degradation of PET fibers by enzyme. It was found that the addition of Triton X-405 can improve the concentration of degradation products. However, other surfactants selected in this paper, such as Tween-80 caused the decrease of the degradation yields. The results indicated that the structure of surfactant plays a very important roll on the degradation of PET catalyzed by enzyme. This is probably due to the transformation of enzyme conformation induced by surfactant, and affects on the activity of enzyme. The hydrophilic surface is beneficial to the adsorption of enzyme onto the surface of PET fibers, and further improve the degradation of PET fibers.

Impact resistance of recycled-PET fiber strengthened wave-dissipating concrete block considering rocking motion

This study was conducted to enhance the impact resistance of wave-dissipating concrete blocks by recycled-Polyethylene Terephthalate (rPET) fibers. The aim of this study is to address the structural vulnerabilities of maritime structures and contribute to environmental issue. Traditionally, the stability of marine structures has been largely dependent on self-weight, a characteristic that can be undermined by damage from sea waves. Wave-dissipating concrete blocks are engineered to reduce the power of waves, but they remain susceptible to fractures caused by hoisting and rocking motions after installation. Existing evaluations often neglect the impact of rocking motion, primarily concentrating on fractures due to lifting. To enhance impact resistance, ultra-slow speed experimental tests were conducted to determine the fracture energy of concrete block considering rPET. The results revealed a significant improvement in the fracture energy of rPET reinforced concrete. Based on these experimental test results, a numerical model was developed to simulate the behavior of wave-dissipating concrete blocks considering rocking motion. The developed Smoothed Particle Hydrodynamics (SPH) model proved to be more relevant than the Finite Element (FE) model. Furthermore, this newly developed numerical model was utilized to evaluate structural performance. The results of the numerical analysis indicated a relationship between weight and impact velocity on the occurrence of damage. This led to the proposal of fragility curves for Sealock and TTP under various impact velocities during rocking motion. Fragility curves, developed based on impact velocity, demonstrated enhanced impact resistance of wave-dissipating concrete blocks reinforced with rPET. In addition, the incorporation of PET fibers effectively controlled crack propagation and improved impact resistance, particularly with increasing block weight. The methodology employed in this study holds potential for predicting outcomes using simple data, making it applicable to other scenarios such as vehicle-bridge pier collisions.

Toward a Sustainable Approach for Durably Hydrophilic and UV Protective PET Fabric through Surface Activation and Immobilization Integrating Epigallocatechin Gallate and Citric Acid.

Enhancing the hydrophilicity and UV protective property of poly(ethylene terephthalate) (PET) fabric are two significant ways to upgrade its quality and enlarge the applicable area. Biobased finishes are greatly welcomed for the fabrication of sustainable textiles; however, their application on PET fabric is still challenging compared with the case of natural fabric. This study presents a strategy that immobilizes epigallocatechin gallate (EGCG) onto PET fabric using citric acid (CA) for durably hydrophilic and UV-proof properties with negligible color change. A controllable surface-activating method integrating alkaline and deep eutectic solvent (DES) is customized for the PET fabric to promote the reactions among PET, CA, and EGCG. The hydrophilic, antistatic, and UV protective properties of functionalized PET fabric were explored. Results show that the hydrophilicity of the PET fabric after direct EGCG treatment increases but drops sharply after first-round washing due to weak interactions. The combined alkaline/DES pretreatment increases the number of hydrophilic groups and the roughness of PET fibers. After EGCG modification, the moisture regain (MR) of PET fabric increases from 0.41 to 0.64%. The contact angle and electrostatic charge half-life (T1/2) decreases from >120 to 23°, and from >60 to 0.13 s, respectively. The MR and T1/2 are well retained after a 10-cycle washing. In addition, the UV protective factor of the PET fabric increases from 18 to 36. A very slight yellowing phenomenon occurs on the PET fabric after the treatment. In all, this research attempts to integrate a biobased finishing agent and an eco-friendly cross-linker on synthetic fiber for durable functions, which is transferrable to the sustainable fabrication of other polymeric materials such as fibers or films.

Raman imaging spectroscopic solutions for microplastics advanced analysis: Insights from Choqueyapu river basin (La Paz, Bolivia)

Microplastics (MPs) are causing global concern due to their role as vectors of environmental contaminants. Evaluating their impact on environmental compartments, particularly in sediment and freshwaters, remains challenging due to difficulties in gathering chemical and morphological data. In fact, the analytical process can vary depending on the matrix considered, the non-homogeneous characteristics of MPs, and the targeted size range. Sample treatment is crucial for sediments and waters, requiring a balance between matrix removal and preservation of the MPs. Consequently, MPs often remain embedded in significant amounts of the original matrices, compromising their characterisation. In this regard, Raman spectroscopy shows promise for their comprehensive molecular analysis. However, overcoming the drawbacks associated with fluorescence from organic matter, feldspar, or clays requires considerable effort. Effective signal acquisition necessitates fine-tuning parameters, including background reduction and signal-to-noise ratio amplification. Moreover, data handling involved in chemical scanning large surfaces at high resolution is a challenging task. To overcome these drawbacks, chemometrics have demonstrated high efficacy in processing and extracting targeted information. The application of chemometrics could be relevant in environmental studies due to the large number of samples, the complexity of signal acquisition, and the dataset volumes managed. As such, this study proposes spectroscopic analytical solutions, augmented by chemical imaging and algorithmic processing, for advanced MPs analysis. A spectroscopic working approach was devised and tested through a real case study conducted in the Choqueyapu River basin (La Paz, Bolivia). This methodology allowed the morphological, molecular and quantitative identification of over 44 particles/L and 91 MPs particles/kg, in water and sediment, respectively, consisting of PE, PET, PP, PS and PMMA. MP abundance varied significantly across studied areas, spanning 2 to 4 orders of magnitude. PET fibres predominated in freshwaters, while Lipari Sector sediments were hotspots for PE and PS fragments.