Recycled Polyethylene Terephthalate Research Articles

Laser-Induced Carbonization of Ni-BDC Layer on PET: Functional Upcycling of Polymer Wastes Towards Bend Resistive Sensor

The growing accumulation of waste polyethylene terephthalate (PET) presents a significant environmental challenge requiring the development of sustainable recycling methods. In this study, a novel approach for upcycling preliminary recycled waste PET into bend resistive sensors through laser-assisted carbonization of surface-grown Ni-BDC (BDC = 1,4-benzenedicarboxylate) has been proposed. The fabrication process involves the solvothermal formation of a homogeneous Ni-BDC layer, followed by treatment with a 405nm laser system to create a graphene-like layer with enhanced conductivity (sheet resistance 6.2 ± 3.4 Ω per square). The developed sensor demonstrates remarkable robustness, a linear response in a wide bending angle range (6 to 44º), as well as excellent mechanical stability and stiffness. This contribution paves the way for the development of high-value materials from waste PET as a resource for applications in the Internet of Things, otherwise discarded materials.

Utilizing in-nozzle impregnation for enhancing the strength of recycled PET-derived 3D printed continuous banana fiber reinforced bio-composites

Purpose This study aims to evaluate the potential of using the in-nozzle impregnation approach to reuse recycled PET (RPET) to develop continuous banana fiber (CBF) reinforced bio-composites. The mechanical properties and fracture morphology behavior are evaluated to establish the relationships between layer spacing–microstructural characteristics–mechanical properties of CBF/RPET composite. Design/methodology/approach This study uses RPET filament developed from post-consumer PET bottles and CBF extracted from agricultural waste banana sap. RPET serves as the matrix material, while CBF acts as the reinforcement. The test specimens were fabricated using a customized fused deposition modeling 3D printer. In this process, customized 3D printer heads were used, which have a unique capability to extrude and deposit print fibers consisting of a CBF core coated with an RPET matrix. The tensile and flexural samples were 3D printed at varying layer spacing. Findings The Young’s modulus (E), yield strength (sy) and ultimate tensile strength of the CBF/RPET sample fabricated with 0.7 mm layer spacing are 1.9 times, 1.25 times and 1.8 times greater than neat RPET, respectively. Similarly, the flexural test results showed that the flexural strength of the CBF/RPET sample fabricated at 0.6 mm layer spacing was 47.52 ± 2.00 MPa, which was far greater than the flexural strength of the neat RPET sample (25.12 ± 1.94 MPa). Social implications This study holds significant social implications highlighting the growing environmental sustainability and plastic waste recycling concerns. The use of recycled PET material to develop 3D-printed sustainable structures may reduce resource consumption and encourages responsible production practices. Originality/value The key innovation lies in the concept of in-nozzle impregnation approach, where RPET is reinforced with CBF to develop a sustainable composite structure. CBF reinforcement has made RPET a superior, sustainable, environmentally friendly material that can reduce the reliance on virgin plastic material for 3D printing.

Reinforcing effects of ground tyre rubber on physical, mechanical, and thermal properties of polyethylene terephthalate

This study examines the use of waste and recyclable polyethylene terephthalate (rPET) along with micro-sized ground tire rubber (GTR) to produce a polymer matrix composite (PMC) material. The PMC materials are made in a Twin-screw extruder, with different ratios of rPET to GTR ranging from 90:10 to 50:50. In order to assess the performance of the newly created rPET-GTR matrix composite materials, the physical, mechanical properties are empirically observed. The thermal properties and crystallinity (Xc) of PMC materials are analysed using DSC. SEM and microscopic imaging are used to determine the characteristics of rPET-GTR composite materials, including elemental compositions like carbon, oxygen, and silicon. The functional group and chemical structure are confirmed through IR spectra analysis using FTIR techniques. The inclusion of micro-sized GTR has shown a significant effect on the physical (density = 1.306 - 1.208 g/cm3, water absorption = 1.76%–10.74%, and melt flow index = 8.12 - 12.79 gm/10 min), mechanical (tensile strength = 52.78 – 73.58 MPa, impact strength = 110.64 - 138.44 J/m, hardness = 56.14 - 76.37, and flexural modulus = 66.23 - 106.32 MPa), and thermal (melting temperature = 220.25°C–192.57°C, Xc = 20.30 to 30.58%) properties of rPET. These studies all work together to improve the performance of waste rPET and GTR materials by repurposing them. It helps to promote sustainability, cost-effectiveness, and expands the range of applications (automotive parts, building materials, sports equipment, electrical insulation and prosthetics) for rPET-based composites with potential uses in the polymer industries.

Effects of Gamma Irradiation on Polyethylene Terephthalate and Detection of Microplastic Particles Down to 1 μm.

In response to increasing concern about the impact of plastic degradation on the environment, this study investigates the degradation of virgin and recycled polyethylene terephthalate (PET) under γ-irradiation in aqueous solutions, with particular focus on the resulting formation of microplastic particles (MP). By exposing both virgin and recycled PET samples to different doses of γ-irradiation (10, 50, and 100 kGy), a comprehensive analysis using UV-vis spectroscopy, dynamic light scattering (DLS) and micro-Raman spectroscopy is presented. The results, highlighted by micro-Raman spectroscopy, show that γ-irradiation produces micrometer-sized plastic particles, with the recycled PET having a significantly higher MP content than its original counterpart. Careful examination reveals the presence of a stabilizer in samples of recycled PET juice bottles. This study not only contributes to our understanding of the effects of γ-irradiation on PET but also highlights the need for further research into the environmental impact of such processes. The insights gained shed light on the behavior of PET under γ-irradiation and the resulting impact on microplastic pollution and make an important contribution to our understanding of the broader environmental context.

Influence of Physical–Mechanical Strength and Water Absorption Capacity on Sawdust–Waste Paper–Recycled Plastic Hybrid Composite for Ceiling Tile Application

In recent times, there has been a notable surge in the interest in promoting environmentally conscious products, particularly within the building industry where the focus has shifted towards sustainable materials. In this study, as a sustainable building material, ceiling tiles have been fabricated as a composite board containing waste materials, namely waste paper, sawdust, recycled polyethylene terephthalate (PET), and epoxy resin, and characterized comprehensively through physical and mechanical tests, density, thickness swelling (TS), modulus of elasticity (MOE), modulus of rupture (MOR), and flexural strength (FS) for product stability. A total of nine composites were fabricated with different ratios through molding techniques, and the characterization results were compared to determine the optimized stable ratio of composite composition. The composition of 25% waste paper, 15% sawdust, 10% recycled PET, and 50% epoxy resin presented the maximum FS compared to the other composite ratios. Water absorption (WA) and thickness swelling were evaluated after immersion durations of 1–24 h. The findings revealed that as the density increased, the sawdust content within the matrix decreased from 25–35%. Concurrently, an increase in recycled PET content resulted in decreased water absorption and thickness swelling. Significantly, the MOE, MOR, and FS demonstrated optimal values at 864.256 N/mm2, 12.786 N/mm2, and 4.64 MPa, respectively. These observations represent the excellent qualities of this hybrid composite board, particularly in terms of sustainability, stability, and water absorption capacity. Moreover, its lightweight nature and ability to support ceiling loads further enhance its appeal for construction applications. This study not only advances the discourse on sustainable construction materials but also fosters opportunities for broader acceptance and innovation within the industry.

Improving hydrophobicity of asphalt surfaces using pulverized recycled polyethylene terephthalate: Towards efficient roofing/waterproofing

Hydrophobic surfaces exhibit low wettability, low water and ice adhesion, etc. with an enhanced water resistance overall. Asphalt binder is popularly employed for roofing and waterproofing due to its intrinsic hydrophobicity. Yet, both unmodified and conventionally polymer-modified asphalt binders exhibit water contact angle (WCA) within the lower hydrophobic range (≤ 121°). Recent studies have shown that the hydrophobicity of asphalt binder can be enhanced via surface treatment using carefully selected materials. In this current study, the use of recycled polyethylene terephthalate (rPET) to improve the hydrophobicity of asphalt-binder was explored. The rPET was processed into micro-sizes and utilized to thermally treat the asphalt-binder at 100 °C. The morphology of the processed rPET and the treated-asphalt surfaces was examined using scanning electron microscopy (SEM). An optical surface profilometer was employed to quantify the roughness of the treated-asphalts. A video contact angle measurement system was used to measure the WCA of the unprocessed/untreated materials and the treated asphalt surfaces. The treated-asphalt showed average and maximum WCA of up to 144° and 148° respectively. This indicates that the rPET-treated asphalt surface could exhibit super-hydrophobicity (WCA ≥ 145°). The improvement in the WCA was due to the increase in surface roughness as a result of the embedment of rPET-particles onto the asphalt surface. The embedment resulted in the stretching of the asphalt surface, forming micro-valleys and -ridges of multiple hierarchies. Higher curing duration was found to yield treated-asphalts with hydrophobicity that last longer. It is found that micronized rPET with sizes smaller than 149 µm can be employed to successfully improve the hydrophobicity of asphalt binder surfaces.

Structural and sound absorption properties of polyethylene terephthalate (PET) and recycled polyethylene terephthalate (r-PET) nanofibers

Sound-absorbing materials are used to reduce noise pollution since noise is one of the important environmental factors affecting human health. Due to their high porosity and large specific surface area, nanofibers can be preferred as a better sound absorption material. In this study, nanofiber-based sound-absorbing materials are produced using polyethylene terephthalate (PET) and recycled polyethylene terephthalate (r-PET) in the electrospinning method in order to obtain a thin and high-sound absorbing material. Another objective of this study is to investigate the performance of r-PET compared to PET from the sound absorbing properties points of view to contribute sustainability which is one of the most important issues of today. For these purposes, solutions of three different concentrations (10%, 15% and 20% owf) were prepared by dissolving PET and r-PET polymers in trifluoroacetic acid (TFA):dichloromethane (DCM) solvent mixture. It will also be possible to help sustainability issues by reducing environmental pollution and raw material costs by using r-PET. Samples were electrospun on a polypropylene based nonwoven structure using solutions at different flow rates (0.1-0.3-0.5 ml/h) and needle tip-collector distances (4–8 cm). The fiber diameter, thickness, bulk density, porosity and pore size properties of the produced samples were investigated. The sound absorption coefficient (SAC) was measured with a dual microphone impedance tube device. The relationship between the structural properties of the samples and the SAC was evaluated. SAC decreased with increasing fiber diameter, bulk density, pore size and increased with high porosity. These values were compared with different sound absorbing materials which are commonly used. According to the results, the developed nanofiber-based material with a 0.3 mm thickness has high SAC values compared to conventional sound absorbing materials with 10–16 mm thickness values, especially in middle frequency levels. Recycled polymer may be preferred when PET and r-PET nanofibers show similar results.

Global Polyethylene Terephthalate (PET) Plastic Supply Chain Resource Metabolism Efficiency and Carbon Emissions Co-Reduction Strategies

Polyethylene terephthalate (PET) is widely used as a primary plastic packaging material in the global socio-economic system. However, research on the metabolic characteristics of the PET industry across different countries, particularly regarding the entire life cycle supply chain of PET, remains insufficient, significantly hindering progress in addressing plastic pollution worldwide. This study employs the Life Cycle Assessment-Material Flow Analysis (LCA-MFA) method to comprehensively analyze the environmental impacts of PET plastics, with a focus on the processes from production to disposal in 12 regions (covering 41 countries) in 2020. By constructing 13 scenarios and analyzing the development trajectory of PET plastics from 2020 to 2030, this study provides scientific evidence and specific strategies for waste reduction and emission reduction measures in the PET industry. Overall, in 2020, the 12 regions (41 countries) consumed 7297.7 kilotons (kt) of virgin PET resin and 1189.4 kt of recycled PET resin; 23% of plastic waste was manufactured into recycled PET materials, 42% went to landfills, and 35% was incinerated. In 2020, the entire PET plastic supply chain emitted approximately 534.6 million tons (Mt) of carbon dioxide equivalent per year, with production emissions accounting for 46.1%, manufacturing stage emissions accounting for 44.7%, and waste treatment stage emissions accounting for 9.2%. Research indicates that under a scenario of controlled demand, resource efficiency improvement and emission reduction are the most effective, potentially reducing carbon emissions by up to 40%.

Quantification of Recycled PET in Commercial Bottles by IR Spectroscopy and Chemometrics

A novel approach for the quantification of recycled polyethylene terephthalate (r-PET) in commercial bottles is presented. Fifty-eight bottle samples from several brands and producers containing different percentages of r-PET were purchased from the market. Samples were analyzed by two spectroscopic methods: near-infrared (NIR) spectroscopy and attenuated total reflection (ATR) spectroscopy in the mid-infrared (MIR) region. No chemical pre-treatment was applied before analyses. The spectra were analyzed by partial-least squares (PLS) regression, and two models for NIR and MIR data were computed. Then, a multi-block regression was applied to join the two datasets. All models were validated by cross-validation and by excluding and projecting onto the model the replicated spectra of one sample at a time. Results demonstrated the potential of this approach, especially considering the variability of commercial samples in terms of additives, shape, or thickness of the bottles: for samples close to the centroids of the models (i.e., from 10 to 50% r-PET), the predictions of multi-block method seldom departed from the expected values of ±10%. Only for samples with 0% declared r-PET, the models showed poor prediction abilities.

A New Sustainable PPT Coating Based on Recycled PET to Improve the Durability of Hydraulic Concrete.

A new, sustainable polypropylene terephthalate (PPT) coating was synthesized from recycled polyethylene terephthalate (PET) and applied onto a hydraulic concrete substrate to improve its durability. For the first step, PET bottle wastes were ground and depolymerized by glycolysis using propylene glycol (PG) in a vessel-type reactor (20-180 °C) to synthesize bis(2-hydroxypropyl)-terephthalate (BHPT), which was applied as a coating to one to three layers of hydraulic concrete substrate using the brushing technique and polymerized (150 °C for 15 h) to obtain PPT. PET, BHPT, and PPT were characterized by FT-IR, PET, and PPT using TGA, and the PPT coatings by SEM (thickness), ASTM-D3359-17 (adhesion), and water contact angle (wettability). The durability of hydraulic concrete coated with PPT was studied using resist chloride ion penetration (ASTM-C1202-17), carbonation depth at 28 days (RILEM-CPC-18), and the absorption water ratio (ASTM-C1585-20). The results demonstrated that the BHPT and PPT were synthetized (FT-IR), and PPT had a similar thermal behavior to PET (TGA); the PPT coatings had good adhesion to the substrate, with thicknesses of micrometric units. PPT coatings presented hydrophilic hydrophilic behavior like PET coatings, and the durability of hydraulic concrete coated with PPT (2-3 layers) improved (migration of chloride ions decreased, carbonation depth was negligible, and the absorption water ratio decreased).

Flexible and rigid block copolymers from recyclable polyesters

The paper addresses a study on the thermoplastic elastomers (TPE) that can be synthesized using monomers retrieved from the chemically recycled semi-aromatic polyesters, such as terephthalic acid from low value stream recyclable polyethylene terephthalate (rPET). In contrast to PET, because of their physical and mechanical properties, TPEs are often used as an engineering polymer in automotive and consumer goods. The understanding of the crystallization and phase behavior of these materials is crucial to fine-tune the molecular structure and properties. We explore the interplay between the crystallization and phase separation in these materials by performing experiments on model thermoplastic elastomers consisting of polybutylene terephthalate (PBT) and polytetrahydrofuran (PTHF). A common denominator in the synthesis of PBT is terephthalic acid that can be obtained from Dimethyl Terephthalate (DMT) or recycling used PET. We show that by varying the compositions and block length of different blocks, in PBT-PTHF block copolymers, morphological variations from spherulites to dendrites can be induced, which could be captured using optical microscopy. By performing rheological and small angle X-ray scattering studies, we correlate these morphological variations at microscopic length scales, to the chain architecture at nanometer length scales. Our observations reveal that at the higher rigid PBT content, the process of phase separation strongly influences the crystallization kinetics that promotes the lamellar structure of the semi-crystalline polymer, observed at room temperature. On the other hand, in the presence of higher soft block content, the crystal growth occurs with minimal influence of the microphase separation. In broader generality, no morphological differences in the TPEs synthesized using the terephthalic acid from rPET are found. However, when the monomer from rPET is used, enhancement in crystallization rate occurs in the TPEs having similar molar mass and molecular configuration. We attribute the enhanced crystallization rate to the catalyst residues present in the terephthalic acid obtained fom rPET.

Graphene-loaded recycled PET: Exploring and enhancing electrical conductivity through processing and laser treatments near the electrical percolation threshold

The blend of polyethylene terephthalate (PET), among the most employed polymer, with graphene, among the most adopted conductive carbon materials, may represent a favorable and sustainable approach for the fabrication of added-value conductive composite materials. This work targeted on the fabrication of melt-compounded composites via injection molding process starting from homemade recycled PET and different loadings of graphene nanoplatelets (GnPs) with different lateral sizes (5 and 25 μm, respectively), used as conductive fillers. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and SEM investigation of the different r-PET/GnP-based compounds provided information about composition, textural and structural properties of the melt-compounded specimens, which were correlated with their DC electrical properties. Graphene loadings higher than ca. 9.5–10 wt% were found enough to achieve the electrical percolation within the two material types. With higher graphene loadings, electrical conductivity increased, due to the formation of a progressively developed percolation network. Notably, the effects of the different GnP loadings, GnP lateral sizes and crystallinity degree of the polymer on the conductivity of the of the melt-compounded specimens were investigated. Furthermore, the effect on the electrical properties of CO2 laser irradiation at different scribing speeds on r-PET/GnP composites with graphene loading below the percolation threshold, was verified. By altering locally the morphology and structure, the irradiation process impacted the electrical properties. Notably, the resulting low sheet resistance suggests potential applications in low-power electronics. In brief, the approach and methodology adopted in the present work, along with the results, can contribute to the development of future upcycling into more valuable and sustainable conductive materials and devices based on recycled PET with a reduced environmental footprint.

Green disposal of waste smartphone protective film: Efficiency, mechanism, bench-scale test and secondary waste reutilization

The manufacture and obsolescence of smartphones produce numerous waste plastic accessories (e.g., waste smartphone protective film (WSPF)), possessing immense potential for recycling. However, available recycling technologies have limitations such as substrate damage and secondary pollutant generation. The present study aimed to develop a green disposal method that not only recycled polyethylene terephthalate (PET) from WSPF, but also reused the stripped polyacrylate (PAA) adhesive as an adsorbent to reduce solid waste generation. When the WSPF was treated in 1 mol/L NaOH solution at 90 °C, the PAA hydrolyzed to two main by-products of 1-butanol and 2-ethylhexanol, weakening the binding strength between PAA and PET and then efficient separation of them. Further bench-scale test revealed that over 97.2% of detachment efficiency toward PAA was achieved during continuous treatment of 17 batches of WSPF (200 g for each) without supplement of NaOH and generation of wastewater. Meanwhile, the economic evaluation indicated that the recycling method would generate a net profit margin of 647% for the second year without considering the incurrence of new cost and input. Additionally, the pyrolysis of waste PAA enabled its conversion into potential adsorbent, which showed 2 to 4 times enhanced adsorption capacity toward styrene and ethyl acetate after modification with NaOH solution. This study provides a green method for recycling waste plastics and inspires a referable solution for solid waste treatment in the smartphone industry.

High versatility of polyethylene terephthalate (PET) waste for the development of batteries, biosensing and gas sensing devices

Continuously growing adoption of electronic devices in energy storage, human health and environmental monitoring systems increases demand for cost-effective, lightweight, comfortable, and highly efficient functional structures. In this regard, the recycling and reuse of polyethylene terephthalate (PET) waste in the aforementioned fields due to its excellent mechanical properties and chemical resistance is an effective solution to reduce plastic waste. Herein, we review recent advances in synthesis procedures and research studies on the integration of PET into energy storage (Li-ion batteries) and the detection of gaseous and biological species. The operating principles of such systems are described and the role of recycled PET for various types of architectures is discussed. Modifying the composition, crystallinity, surface porosity, and polar surface functional groups of PET are important factors for tuning its features as the active or substrate material in biological and gas sensors. The findings indicate that conceptually new pathways to the study are opened up for the effective application of recycled PET in the design of Li-ion batteries, as well as biochemical and catalytic detection systems. The current challenges in these fields are also presented with perspectives on the opportunities that may enable a circular economy in PET use.

A new circulation in glycolysis of polyethylene terephthalate using MOF-based catalysts for environmental sustainability of plastic

The relentless growth of plastic has emerged as a significant environmental and human health concern. Catalytic glycolysis of polyethylene terephthalate (PET) has proven to be an effective solution. This study investigated a series of M−BDC (M = Ni, Co, Cu, and Zn) metal–organic frameworks as catalysts for PET glycolysis. Zn−BDC exhibited the best experimental performance. Subsequently, the effects of operating conditions were optimized for the first time through a comprehensive investigation using a model based on deep neural networks (DNNs). The guidance of the DNN model resulted in a BHET selectivity as high as 0.95, outperforming most current heterogeneous catalysts for PET depolymerization. Furthermore, the apparent activation energy was also estimated by kinetic study. In addition, our designed system exhibits high durability after five consecutive runs, reflecting its promising escalation at the industrial level. Notably, the fabrication of the M−BDC framework can utilize the organic linker terephthalic acid (TPA) derived from the BHET monomer. By applying this strategy, we have achieved a significant advancement towards closed-loop PET recycling, contributing to a more comprehensive definition of sustainable development.

Effect of process parameters on the mechanical performance of FDM printed carbon fiber reinforced PETG

Additive manufacturing (AM), shows promising advancements in layer-based modeling displaying its potential for substantial waste reduction. Out of all the AM methods, the most cost-effective and popular choice for prototyping and making customized parts is fused deposition modeling (FDM). This research investigates how various FDM process parameters specifically layer thickness, raster angle, and printing speed affect the mechanical properties of 3D-printed PETG (polyethylene terephthalate glycol) specimens reinforced with carbon fiber (CF). Optimal settings, including a 0° raster angle, 0.2 mm layer thickness, and 40 mm/s printing speed, enhance both tensile and flexural strength due to improvement in material bonding and alignment. Interestingly, lower values for raster angle, layer thickness, and printing speed also lead to notable improvements in mechanical properties. Contour and interaction plots provide valuable insights into the significant impact of these parameters. The study also explores how different printing speeds influence the mechanical characteristics of CF-reinforced PETG specimens. Furthermore, the comparative analysis demonstrated that incorporating carbon fiber into recycled PET waste materials resulted in an approximately 30% increase in tensile strength. These findings imply that using CF with plastic waste in large-scale industries can pave the way for innovative solutions, enhancing performance and sustainability, especially in the automotive, and defence sectors.

Sub-ambient radiative cooling with thermally insulating polyethylene terephthalate aerogels recycled from plastic waste

We demonstrate that the aerogels produced from the polyethylene terephthalate (PET) fibers, recycled from plastic bottle wastes, can function both as a radiative cooler and a thermal insulator. An object under and in contact with the recycled PET aerogel is thermally insulated from the surroundings and, at the same time, cooled below ambient temperature via radiative cooling. These dual capabilities are tested under the warm sky of Singapore with more than 420 W/m2 downwelling. With a 0.48 cm thick recycled PET aerogel, a heat transfer coefficient of 1.67 W/m2·K is measured when the object underneath is cooled by 2 °C from ambient temperature. Even under a 4.5 cm thick recycled PET aerogel, completely opaque to the thermal emission and having a heat transfer coefficient less than 1 W/m2·K, a sub-ambient radiative cooling is observed. Our measured heat transfer coefficient is lower than that of other porous polymer materials or aerogels reported to date as a radiative cooling substrate. Our results demonstrate that the recycled PET aerogels are a multi-functional material, integrating radiative cooling and thermal insulation in a single substrate. Produced by processing waste materials, the recycled PET aerogels hold promise to be a highly scalable and sustainable thermal management solution, with a positive impact on the environment.

Characterization and elimination efficiency of volatile organic compounds in mechanically recycled polyethylene terephthalate at various recycling stages

The recycling of polyethylene terephthalate (PET) stands as an effective strategy for mitigating plastic pollution and reducing resource waste. The study aimed to investigate the characterization and elimination efficiency of volatile organic compounds (VOCs) present in rPET at various recycling stages using comprehensive two-dimensional gas chromatography-quadrupole-time-of-flight-mass spectrometry coupled with chemometrics. The results revealed that 52, 135, 95, 44, and 33 VOCs, mostly classified into three chemical groups, were tentatively identified in virgin − PET (v-PET), cold water washed − rPET (C-rPET), decontaminated − rPET (D-rPET), melt-extruded − rPET (M-rPET), and solid-state polycondensation − rPET (S-rPET), respectively. Regarding the VOCs with high and median detection frequencies, fatty acyls showed the highest elimination efficiency (100 % and 92 %), followed by organooxygen compounds (81 % and 99 %), others (97 % and 95 %), and benzene and substituted derivatives (82 % and 95 %) in term of HS-SPME. Following the recycling process, there was a general decrease in the concentration of almost all VOCs, as evidenced by the substantial reduction of o-Xylene, hexanoic acid, octanal, and D-limonene from 18.11, 22.43, 30.74, and 7.41 mg/kg to 0, 0, 3.97, and 0 mg/kg, respectively. However, it was noteworthy that the VOCs identified in the samples were not completely extracted, owing to the limitations of HS-SPME. Furthermore, chemometrics analysis indicated significant discrimination among VOCs from vPET, C-rPET, D-rPET, and M-rPET, while indistinct differences were observed between M-rPET and S-rPET. This study contributes to the enhancement of the recycling process and emphasizes the importance of safeguarding consumer health in terms of elimination of VOCs.

Utilizing Polyethylene Terephthalate (PET) In Insulation Fired Clay Bricks

In order to improve the thermal insulation properties of fired clay bricks, the addition of polystyrene has been a common practice. However, in this study, we propose an alternative approach by substituting polystyrene with recycled polyethylene terephthalate (PET) derived from drinking water bottles. The PET is shredded and added to the brick composition, with a maximum inclusion level of 25%. Various tests were conducted to evaluate water absorption, apparent porosity, bulk density, cold crushing strength, and thermal conductivity of the bricks at temperatures up to 800 degrees Celsius. The results indicate that incorporating 20% crushed plastic by weight yields bricks comparable to ASTM C155-97 standard bricks.

Impact of the functionalized clay nanofillers on the properties of the recycled polyethylene terephthalate nanocomposites

AbstractPolymer nanocomposites, such as polyethylene terephthalate (PET)‐clay systems, leverage intricate interactions between components to fine‐tune their thermal, mechanical, and rheological properties. In our study, we functionalized montmorillonite clay nanofillers (CloisiteNa+) to fabricate recycled PET‐clay nanocomposites. The nanofillers underwent a three‐step functionalization process, involving the treatment with (3‐Aminopropyl)triethoxysilane (APTES), the grafting of initiating coatings (multifunctional peroxide initiator, [MPI]) onto clay/APTES, and the subsequent fabrication of grafted brushes using poly(butyl methacrylate) (PBMA) or poly(butyl acrylate) (PBA). The functionalization process and the properties of the modified clay were successfully confirmed through Fourier‐transform infrared spectroscopy and thermogravimetric analysis. The fabrication of nanocomposites, incorporating both clay and functionalized clay, influenced the thermal behavior of the composites, whereas the nanofillers had no discernible impact on the flow temperature. The PET and nanocomposites exhibited liquid viscoelastic behavior, with the exception of PET with clay, which displayed shear‐thinning and “rubber‐like” behavior. Rheological curves and x‐ray diffraction (XRD) analysis indicated improved dispersion and compatibility for clay/APTES and clay functionalized with PBA‐grafted brushes within the PET matrix. In some instances, the utilization of functionalized clay resulted in enhanced compatibility and customized properties in PET‐organoclay nanocomposites compared with conventional fillers. These findings bear implications for a broad spectrum of applications involving PET‐organoclay nanocomposites.