Polymer Waste Research Articles

Characterization of Polypropylene Composite Reinforced on Bio-waste from the Production of Tung Oil

The aim of the conducted study was to develop wood-polymer composites (WPCs) using secondary polymer waste and agricultural technology waste materials, which would have lower environmental impacts than WPCs made from virgin resources. The study focused on developing WPCs based on polypropylene filled with finely dispersed powders of waste products from tung oil production (PP+TOPW composites). Finely scattered powder (with an average grain size of 0.5–1.5 mm) was obtained from crushing and grinding the outer pericarp of tung fruit waste, which resulted from tung oil extraction. Tung oil is produced in Georgia from tung fruit that is grown in Tsalenjikha district, Georgia. In addition, to modify the properties of the WPCs, organic silicon oligomer tetraethoxysilane and powdered aluminum hydroxide were used as additives. The study found that the strength properties of the PP+TOPW composites can be optimized by modifying them with tung oil and other mineral additives. The optimal strength properties were observed at a filler content of 40 wt.%, where the compression and bending strength limits were 63.5 and 36.7 MPa, respectively. The water absorption of the PP+TOPW composites was reduced by modifying them with tung oil. The PP+TOPW composites with a filler content of 30 wt.% showed 0% water absorption, and the water absorption of composites with a filler content of 40 and 50 wt.% (modified with tung oil) was very low, ranging from 0.2–0.8%. The study also investigated the effect of modifying PP+TOPW composites with tetraethyl orthosilicate (TEOS), which increased all the strength parameters, including impact strength, and reduced water absorption, although not as much as when modified with tung oil. The introduction of a flame retardant, aluminum hydroxide, into the composite composition in the amount of 25–30 wt.% made the composites flame-retardant and low-combustible materials, expanding their potential applications, particularly in construction. Overall, the study successfully developed WPCs using waste materials with optimized properties, which have potential for various applications, including in construction, due to their flame retardant and low-combustible properties.

Aging Process of Biocomposites with the PLA Matrix Modified with Different Types of Cellulose.

In the modern world, many products are disposable or have a very short lifespan, while at the same time, those products are made from materials that will remain in the environment in the form of waste for hundreds or even thousands of years. It is a serious problem; non-biodegradable polymer wastes are part of environmental pollution and generate microplastics, which accumulate in the organisms of living beings. One of the proposed solutions is biodegradable polymers and their composites. In our work, three types of polylactide-based composites with plant-derived fillers: microcellulose powder, short flax fibers, and wood flour at 2 wt.% were prepared. Poly(lactic acid) (PLA)-based biocomposite properties were characterized in terms of mechanical and surface properties together with microscopic analysis and Fourier-transform infrared spectroscopy (FTIR), before and after a UV (ultraviolet)-light-aging process to determine the effects of each cellulose-based additive on the UV-induced degradation process. This research shows that the addition of a cellulose additive can improve the properties of the material in terms of the UV-aging process, but the form of the chosen cellulose form plays a crucial role in this case. The testing of physicochemical properties demonstrated that not only can mechanical properties be improved, but also the time of degradation under UV light exposure can be controlled by the proper selection of the reinforcing phase and the parameters of the extrusion and injection molding process. The obtained results turned out to be very interesting, not only in terms of the cost reduction of the biocomposites themselves, as mainly the waste from the wood industry was used as a low-cost filler, but also that the additive delays the aging process occurring during UV light exposure. Even a small, 2 wt.% addition of some of the tested forms of cellulose delayed surface degradation, which is one of the most important factors affecting the biodegradation process.

New policy framework for circular economy in South Korea: Achieving both management and chemical recycling of polymeric waste via pyrolysis reaction

New policy framework for circular economy in South Korea: Achieving both management and chemical recycling of polymeric waste via pyrolysis reaction

Waste polypropylene filter induced synthesis of pure phase Fe3O4 and ZVI incorporated carbon composite for non-radical peroxymonosulfate activation dominated sulfamethoxazole degradation: Singlet oxygen versus electron transfer process

In this study, waste polyethylene (PP) obtained from obsoleting water purifier filter was mixed with ferric chloride hexahydrate (FeCl3·6H2O) to prepare a series of single crystal phased iron compound incorporated carbon composites (Fe/PP-C). The prepared Fe/PP-Cx catalysts were then utilized to degrade sulfamethoxazole (SMX) in water by activating peroxymonosulfate (PMS). The results showed that with the assistance of pyrolysis temperature regulation, waste PP filter could control the crystalline phase of the iron compound in the prepared Fe/PP-Cx through releasing distinct gaseous atmospheres at respective pyrolysis temperature. When the pyrolysis temperature was set at 600 °C and 900 °C, pure phase ferric oxide (Fe3O4) and zero-valent iron (ZVI) incorporated carbon catalysts were obtained, respectively. 0.2 g/L of Fe/PP-Cx could completely degrade 0.02 mM of SMX within 20 min, in which the toxicity of the reaction solution was also effectively reduced. In both Fe/PP-Cx/PMS systems, non-radical mechanisms dominated the SMX degradation, in which singlet oxygen played the dominant role in the Fe/PP-C600/PMS system, whereas electron transfer process was primarily responsible for SMX degradation in the Fe/PP-C900/PMS system. High-valent iron-oxo species was also involved in SMX degradation in the Fe/PP-C900/PMS system. Since Fe/PP-C600 and Fe/PP-C900 respectively activated PMS via heterogeneous and homogeneous routes, Fe/PP-C600 maintained higher longtime use stability. This study aims to present a simple approach to manipulate the nonradical organic pollutant degradation mechanisms in PMS activated system, which also provides a new strategy of utilizing waste polymer.

Nanomembrane Approach Reuses Waste, Cleans Produced Water

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 213946, “Nanomembranes From Polymeric Waste for Produced-Water Treatment,” by Anton Manakhov, Iaroslav Rybkin, and Fahd I. AlGhunaimi, Saudi Aramco, et al. The paper has not been peer reviewed. _ In the oil and gas sector, produced water is the most significant waste stream. Among the different materials used for water filtration, including ceramics, polymers, and carbon nanomaterials, polymeric nanofibers can be considered a unique solution that can be used as a membrane or an adsorbent. In the complete paper, the authors write that polymeric nanofibers can be prepared from polystyrene waste. Introduction The management of polystyrene trash and recycling creates a significant environmental problem. While most of this substance ends up in landfills, only a small portion of polystyrene is recycled or burned. By turning this trash into products with added value, recycling will become more appealing economically and will result in lower CO2 emissions and less chemical waste dumped on the ground. At the same time, the use of modified nanofiltration membranes for generated-water purification has been a subject of study for many researchers. The complete paper includes a review of the literature dedicated to advances in this approach. Dissolved polystyrene waste can be used as a feedstock in the electrospinning process to create nanofibrous membranes. Electrospinning is one of the more basic methods for producing nanofibers with dimensions ranging from micrometers to nanometers. Strong electrostatic forces are used to overcome the surface tension of a polymer solution or melt. These pressures produce the ejection of charged polymer jets, which dry as they approach a grounded electrode, where they are gathered as nanofibers. In this work, the nanofibrous polystyrene membranes were prepared from discarded expanded polystyrene waste. Initially, polystyrene waste was collected and dissolved in an organic solvent; then, the nanofibrous membranes were prepared by the electrospinning of nanofibers from this solution. The morphology, pore sizes, and other parameters were controlled and optimized by tuning the concentration of polystyrene, the nature of the solvent, and the spinning voltage to form uniformly sized nanofibrous membranes.

EXPERIMENTAL STUDY OF SAMPLES MANUFACTURED FROM CRUSHED POLYMER WASTE ON A 3D PRINTER WITH A SCREW EXTRUDER

The article conducts an experimental study of samples made from crushed polymer waste on a 3D printer with a screw extruder. General information about the experimental study is given. An analysis of literary sources on the study of mechanical properties of products manufactured by FDM technology on 3D printers was carried out. Two 3D printers were chosen for the production of experimental prototypes, one of which prints with filament, the other with granules or crushed polymer waste. The equipment for determining the accuracy of printed samples has been selected. The measuring part of the tearing machine for taking tensile diagrams of polymer samples has been improved. A strain gauge for force measurement and an optical encoder for displacement measurement are installed in it. A digital electronic system for data collection from sensors based on the Arduino Uno microcontroller was developed. Software for experimental data processing was created. The general view of the experimental setup is given. It is proposed to use uniaxial tension to evaluate the mechanical characteristics of the test samples printed on a 3D printer. Current international standards for tensile testing of plastics are described. To determine the mechanical tensile characteristics, samples in the shape of a blade were made from polymer materials ABS and TPU. The parameters for printing test samples made from these materials are set. With the use of the developed installation, the failure diagrams of samples (blades) made of crushed polymer waste and filament of ABS and TPU plastics with different amounts of internal filling were obtained. In the form of tables, the values of the mechanical characteristics of the samples produced by the 3D printing method from ABS and TPU polymers with different internal filling obtained during the uniaxial tensile test are presented. A photo of the places of breakage of ABS plastic blades, taken using a digital camera, is given. An analysis of the structure of the samples was carried out on them. Experimental test samples were made using two 3D printers to determine the accuracy of 3D printing. Measurements were made in different planes of the test cube using a digital electronic caliper. The obtained results were compared with the created model. Ways to improve print accuracy are described.

Recycling waste polymer packaging materials as effective active carbon porous materials for uranium removal from commercial phosphoric acid

Abstract Plastic packaging waste is considered a serious threat to the environment due to its non-biodegradable nature. Transforming plastic waste into active carbons using pyrolysis methods could be a valuable option to solve the challenge of plastic waste. Synthesized active carbon was differentiated using zeta potential, particle size, SEM, BET, and DSC. This study also investigates the use of obtained active carbons for U(VI) removal from commercial phosphoric acid. The kinetics of adsorption were found to follow the pseudo-second-order model and intra-particle diffusion as one of the controlling mechanisms. Langmuir, and Freundlich, isotherms were employed to explore the equilibrium data. Furthermore, thermodynamic investigations revealed that uranium uptake is an endothermic, feasible, and spontaneous process. The present study concludes that plastic waste-based activated carbon could be employed as a low-cost alternative to commercial activated carbon for uranium removal from phosphoric acid and the production of green fertilizers.

Study of the pyrolysis process of household polymer waste

Study of the pyrolysis process of household polymer waste

Sunflower and Watermelon Seeds and Their Hybrids with Pineapple Leaf Fibers as New Novel Thermal Insulation and Sound-Absorbing Materials.

Pineapple leaf fiber (PALF), striped sunflower seed fiber (SFSF), and watermelon seed (WMS) are considered natural waste polymer materials, which are biodegradable and sustainable. This study presents new novel thermal insulation and sound absorption materials using such waste as raw materials. PALF, SFSF, and WMS were used as loose, bound, and hybrid samples with different compositions to develop promising thermal insulation and sound-absorbing materials. Eleven sample boards were prepared: three were loose, three were bound, and five were hybrid between PALF with either SFSF or WMS. Wood adhesive was used as a binder for both the bound and hybrid sample boards. Laboratory scale sample boards of size 30 cm × 30 cm with variable thicknesses were prepared. The results show that the average thermal conductivity coefficient for the loose samples at the temperature range 20-80 °C is 0.04694 W/(m.K), 0.05611 W/(m.K), and 0.05976 W/m.K for PALF, SFSF, and WMS, respectively. Those for bound sample boards are 0.06344 W/(m.K), 0.07113 W/(m.K), and 0.08344 W/m.K for PALF, SFSF, and WMS, respectively. The hybrid ones between PALF and SFSF have 0.05921 W/m.K and 0.06845 W/(m.K) for two different compositions. The other hybrid between PALF and WMS has 0.06577 W/(m.K) and 0.07007 for two different compassions. The sound absorption coefficient for most of the bound and hybrid boards is above 0.5 and reaches higher values at some different frequencies. The thermogravimetric analysis for both SFSF and WMS shows that they are thermally stable up to 261 °C and 270 °C, respectively. The three-point bending moment test was also performed to test the mechanical properties of the bound and hybrid sample boards. It should be mentioned that using such waste materials as new sources of thermal insulation and sound absorption materials in buildings and other applications would lead the world to utilize the waste until zero agrowaste is reached, which will lower the environmental impact.

Investigation of Adsorptive Removal of Methylene Blue from Synthetic Wastewater Using Polymeric Composite

Recycling polymeric waste into another useful material is considered to be the preferred way of taking care of the issues of slow degradable plastic waste, particularly in anticipation of natural contamination. In this study, the adsorptive treatment of Methylene Blue (MB) using adsorbents from chemically recycled polymeric waste was investigated. Three polymeric materials were employed in this study: styrofoam waste (EPS1), intruded extended polystyrene (EPS2), and sunflower xylem (Tithonia diversifolia xylem) (TDX). The alterations in microscopic surface morphology before and after the adsorption process were examined using scanning electron microscopy (SEM) system to resolve the intercalation of MB with the adsorbent. The experimental batch data was collected and the effects of concentration and contact time on the removal of MB from synthetic wastewater were studied. Adsorption kinetics, equilibrium, and thermodynamics were studied and fitted by various models. According to the result, the uptake of adsorbate increased as contact time and concentration rose, with the pseudo-second-order model best depicting the adsorption kinetics.

Synthesis of Fe-Al catalysts to boost CNTs formation from polymer wastes via the improved two-stage system

Carbon nanotubes (CNTs) has been considering as a high-value product from polymer wastes via the coupled thermal-catalytic technology, and how to improve the yield and quality of CNTs is the key to the further industrialization. Herein, a series of Fe-Al catalysts with different Fe-loading and calcination temperature were prepared and expected to boost CNTs formation from low-density polyethylene (LDPE) in the improved two-stage reaction system. The fresh and spent Fe-Al catalysts were characterized in detail by SEM-EDX, XRD, N2 physisorption, NH3-TPD, H2-TPR, TG-DSC, Raman, and TEM to explore the effects of Fe-loading (5–20%) and calcination temperature (450–650 °C) on the physicochemical properties of Fe-Al catalysts as well as the quantity and quality of CNTs. An increase of Fe-loading generated more active sites for CNTs growth while intensified the competition for the carbon source, promoting the yield while reducing the length of CNTs. A decrease of calcination temperature reduced the interaction between Fe sites and Al2O3 support, promoting both the yield and the length of CNTs. This work provided a promising strategy for optimizing Fe-Al catalysts to boost CNTs production from polymer wastes.

Novel recycled PET/tannin nanofibers for effective removal of lead(II) from water

The pollution of water by hazardous metals such as lead(II) and the growing generation of polymeric wastes such as polyethylene terephthalate (PET) are critical global concerns. Thus, new recycled PET nanofibers functionalized with tannin were applied in the removal of lead(II) from water by adsorption. PET was collected from post-consumer water bottles and obtained as nanofibers by centrifugal spinning. The characterization performed on the nanofibers showed average diameters of 188 nm and functional groups adequate for lead(II) adsorption. Under the adsorption conditions tested, lead(II) adsorption was favored at pH 6 and 328 K, with a maximum adsorption capacity of 350.81 mg g−1. The kinetic data was better represented by the pseudo-first order model. The equilibrium data was better represented by the Sips model. The thermodynamic parameters showed that the process was spontaneous, favorable, and endothermic. The nanofibers kept 45.20 % of their original adsorption capacity after four cycles of adsorption–desorption. The results indicated that the recycled PET/tannin nanofibers are a great alternative as lead(II) adsorbent. They are also an environmentally friendly option for the transformation of an abundant post-consumer polymer into a versatile nanomaterial functionalized with a sustainable biopolymer.

Process Synthesizes Janus Carbon Nanofluids From Waste Plastics for EOR

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214799, “Novel Janus Carbon Nanofluids From Waste Plastics as Sustainable Nanoagents for Enhanced Oil Recovery: Scaleup Synthesis and Performance Evaluation,” by Wei Wang, Sehoon Chang, SPE, and Ayrat Gizzatov, SPE, Saudi Aramco, et al. The paper has not been peer reviewed. _ The complete paper describes nanomaterials—Janus carbon nanofluids—derived from waste plastics and demonstrates the potential of the nanofluids as highly effective alternative nanoagents for enhanced oil recovery (EOR) applications at reservoir conditions. A novel, sustainable, cost-effective method has been developed to scale up synthesis of Janus carbon nanoparticles (JC-NPs) from waste plastic feedstock by combined pyrolysis, chemical functionalization, and pulverization, which allows for production of the JC-NPs in mass quantities at an industrial scale. Introduction Recent research has demonstrated that nanoparticles with asymmetric surface properties (i.e., Janus nanoparticles) could achieve a much higher efficiency of oil recovery factors with very low concentrations of loading compared with homogeneous nanoparticle fluids. To date, however, major challenges facing the exploration and use of Janus nanoparticles exist, impeding scalability of synthesis, tailored chemical functionalization, and the ability to introduce a diverse set of functionalities. Therefore, new methods for production of Janus nanomaterials on an industrial scale are desired. The authors present a novel technique to convert waste plastic materials into carbon-based nanomaterials for EOR applications. Waste plastics, as a low-cost feedstock, can be converted into high-value-added carbon-based microparticles through the controlled carbonization of polymers. Furthermore, the carbon microparticles (C-MPs) can be surface-functionalized by post-chemical treatment and then their chemical symmetry reduced to nanosize by a ball-milling technique. The resulting asymmetrically surface-functionalized carbon nanoparticles (i.e., Janus C-NPs) exhibit both nanoparticulate and surfactant-like properties that can be used as new nanoagents in nanofluid flooding for EOR applications. Experimental materials and measurement methodology are detailed in the complete paper. Results and Discussion Synthesis of C-MPs From Waste Polymers. Approximately 90% of the plastics produced globally consist of six types: low-density polyethylene, high-density polyethylene, polypropylene, polyvinylchloride, polystyrene, and polyethylene terephthalate (PET). Given their widespread use, these waste polymers constitute a substantial proportion of global plastic waste. Therefore, they present an opportunity to be used as precursors in the synthesis of C-MPs. This study offers an approach for repurposing these ubiquitous waste polymers. As depicted in Fig. 1, the authors propose synthesis of C-MPs through carbonization reactions using these waste polymers as feedstock. This methodology offers dual benefits. First, it presents a practical solution to the growing environmental concern posed by plastic waste. Second, it provides a cost-effective way to produce C-MPs, an essential component in many technological applications.

Hardening mechanism of waste polyolefin mixtures in the presence of modified bentonite clay

The aim of the work is to obtain and study polymer composite materials based on mixtures of secondary polyolefins and modified polydisperse bentonite clay. The formation features of the structure of mixtures of waste polyolefins in the presence of this-type filler are studied. The data on the changes in the mechanical strength of mixed composites, as well as the results of physico-chemical studies are presented. Mixtures based on waste polymers in the presence of highly dispersed particles of modified polydisperse bentonite are characterized by the improvement of the strength of composites due to increased interfacial interaction in them and by the formation of structure uniformity of the material. This to some extent compensates for the loss of cohesive strength of secondary polymers due to thermal degradation processes. The following conclusions are made: at the phase boundaries, the molecular mobility of polymer chains decreases, which leads to changing the crystallization conditions and to appearing a nonequilibrium stress state; introducing bentonite increases crystalline due to the initiation of physico-chemical interaction; the strength grows due to increased interfacial interaction and structure uniformity; the formation mechanism of a complex of properties of composites consists of two-level adsorption – a modifier on filler particles and active polymer groups on the modified filler surface.

Determining mechanical and acoustical behaviors of all-recycled PP sandwich structures with bi-directional sinusoidal corrugated core

By recycling the waste polymer material and using it in weight reduction studies of electric vehicles, a double-sided gain is achieved against environmental pollution. Sandwich structures with prismatic cores obtained by recycling waste polymers can be used in structural applications of light and heavy commercial vehicles and public transportation vehicles that carry cargo and passengers. These sandwich vehicle parts could help to increase the max. range and load-carrying capacity of electric vehicles. In this study, sandwich plates with prismatic egg-box cores were produced with waste Polypropylene. Since the materials are collected from different waste sources, the physical properties (additive ratio, secondary substance determination, density) of the recycled material were measured. Thereafter, hardness, quasi-static flatwise and edgewise compression, and 3-point bending tests were done to determine the mechanical properties of the structure. After that, dynamic compression and 3-point bending tests were performed to determine the strength and impact energy absorption capacity of the structure in collision situations. Finally, impedance tube tests were carried out for the acoustic characterization, which is one of the important parameters affecting interior cabin comfort, and Sound Transmission Loss (STL) and Sound Absorption Coefficient (SAC) values of the structure were determined.

Modeling of a screw extruder 3D printer using pellets or crushed polymer waste as the raw material

In this article, the process of moving polymer material in the screw extruder of a 3D printer, which uses granules or crushed polymer waste as raw materials, is chosen as the object of mathematical modeling. It is noted that the modeling of screw extruders is a highly relevant task, as it is an essential tool for optimizing production processes in the polymer industry and other industries where they are used. It allows you to study and optimize the material cylinder's processes thoroughly. It is noted that the modeling of screw extruders for 3D printers, which use granules or shredded plastic waste, is a critical factor in supporting innovation, increasing production efficiency, improving product quality, and developing new technological solutions in various industries. It was noted that during the movement of the material along the channel of the extruder screw, several of its states continuously changed from a solid at the entrance of the channel to a viscous liquid at the exit. In the feed zone, the polymer is solid and moves along the material cylinder due to friction. A physical model was used in the simulation, in which compacted polymer particles do not move relative to each other during movement through the channel. This is because the internal friction forces in the polymer greatly outweigh the friction of the polymer on the steel, and the particles move as a single elastic compressible medium due to the balance of dry friction between the cylinder wall and the screw. The geometrical parameters of the extruder in the feed zone are shown. A diagram of the expanded extruder channel for calculating productivity is given. A diagram of the movement of material in it was drawn up to determine the productivity of the extruder feed zone. A mathematical model of productivity was obtained depending on the diameter of the screw, the frequency of rotation, the depth of the screw channel, and the angle of elevation of the screw line of the screw cutting. The pressure in the extruder channel was calculated. A scheme for calculating the forces acting on the material in the feeding zone is given. A formula was obtained for determining the pressure in the material loading zone from the hopper, which connects the characteristics of the polymer material and the geometric parameters of the loading hopper. Keywords: 3D printer, screw extruder, modeling; polymer material; loading area; bunker; productivity; pressure.

Characterization of PS/PP/HDPE/LDPE Polymer Blend Obtained from Plastic Waste Collected on Beaches in Ilhéus-Bahia, Brazil.

A large volume of polymeric waste is generated in cities, and some of this reaches the sea and beaches. This waste stays for hundreds of years, damaging marine environments and organisms. To minimize the effects of pollution, collection and recycling allow a return to the production chain. This research aims to produce and evaluate a polymeric mixture obtained via processing plastic waste collected on the beaches of the city of Ilhéus-Bahia. Subsequently, the mixture is converted into a granulated form for application as fine aggregate in the production of cementitious matrices. A polymer blend of polystyrene, polypropylene, and high- and low-density polyethylene was obtained and evaluated by thermal, morphological, and mechanical tests in three processing stages. The degradation temperatures were close for the three processing stages and the level of processing influenced the mechanical strength. As for elastic modulus and deformation, there was no significant difference in using the mixture processed once or twice. The results showed that the reuse of the waste is applicable, the mixture presented a compact, reasonably homogeneous material with different morphology. Therefore, this work finds importance in the possibility of promoting waste recycling and adding value to a material that would become waste, thus showing its potential for application in the construction industry as an addition to cementitious mixtures and leading to savings in inputs.

Economic feasibility of catalytic cracking of polymer waste for fuel production

Plastic waste represents a major environmental concern, as it does not degrade in the environment and is constantly discarded. The types of polymers most used in the world are polyethylene and polypropylene, mainly for the production of packaging and, therefore, are the most discarded plastic waste in the environment. Some efforts are being applied to mitigate this situation, such as mechanical recycling, which transforms plastic waste into other products. But polymer cracking processes are promising alternatives, converting waste into lightweight materials that can be turned into commercial fuels. However, to be viable, these processes must consume as little resources as possible and, for this, feasibility experiments must be carried out to prove their application on a large scale and in small transformation units. This work presents a methodology for assembling a low-cost pyrolysis reactor to carry out the cracking of polymeric residues, and experiments were carried out with it, whose results showed the technical and economic viability of the described process, obtaining a rate of conversion of plastic into fuels of up to 96%, so it can be widely applied to reduce impacts caused by plastic disposal.

Non-isothermal thermal decomposition behavior and reaction kinetics of acrylonitrile butadiene styrene (ABS)

Environmental concerns associated with the rapid rising plastic consumption have led to the search for better waste utilization and management. Pyrolysis has emerged as an ideal and promising technique for energy extraction from plastic waste. The aim of this work is to explore the waste plastic pyrolysis behavior under non-isothermal heating conditions. The decomposition characteristics, reaction mechanism, kinetics and thermodynamics of a typical widely used thermosetting plastic, acrylonitrile butadiene styrene (ABS), were studied via coupled thermogravimetry, Fourier transform infrared spectrometry and gas chromatography-mass spectrometry analysis (TG-FTIR-GC/MS). Kinetic analysis showed the average Eα values are estimated to be 187.02, 188.55, 187.04 and 185.67 kJ/mol via advanced Vyazovkin, Flynn-Wall-Ozawa (FWO), Tang and Starink model-free method, respectively. Model-fitting CR and master-plots method indicated that f(α)=(1-α)n is the most probable reaction mechanism. The equation of kinetic compensation effect was further developed as lnA = −3.1955 + 0.1736 Eα. Based on these initial inferences, a new reaction scheme coupled with Particle Swarm Optimization (PSO) was put forward for modeling ABS pyrolysis. The optimized values of E, A and n are 198.07 kJ/mol, 7.61 × 1012 s−1 and 1.56, respectively. The predicted results showed that the experimental data can be well characterized by the optimized parameters from PSO, validating the effectiveness and accuracy of the inverse modeling procedure. Moreover, it is found that the volatile products are mainly composed of aromatic compounds, ketones, amines, esters, nitrile compounds, alkenes and amines. Based on the FT-IR and GC-MS results, the possible chemical reactions for ABS pyrolysis from molecular structure were proposed. Finally, thermodynamic analysis was carried out, the calculated values of enthalpy ΔH, Gibb's free energy ΔG and entropy ΔS indicated that non-spontaneous reactions with low favorability exists during ABS decomposition, the process is complex therefore extra energy is needed to promote the reaction. The obtained results should offer as an important reference for future disposal and thermochemical management of such polymer waste.

The Effects of Bromine Additives on the Recyclability of Injection Molded Electronic Waste Polymers.

Excessive waste amounts, such as waste electrical and electronic equipment (WEEE) and plastic waste, have increased simultaneously with the development of society. Despite the increased material amounts, the recycling rates are too low and those have a great potential to contribute actions toward a circular economy. A certain restricted factor for recycling is the heterogenous nature of materials, such as WEEE-included additives. This study investigates the effects of a WEEE polymer including bromine on recycling ability, analyzing its physical and mechanical features. The study demonstrates that polymer sorting is profitable for WEEE polymers from the material qualitative perspective, because various processability and material features are achieved in the study between material categories, and especially unidentified polymers have the weakest features in the studied tests. The separation of bromine concentration is also recommended because bromine-free materials have more advanced features that can be confirmed by statistical analyses. The achieved results support the idea that novel circular economy actions have the potential for effective, efficient WEEE polymer recycling processes with technological innovations, especially when all variables (e.g., recycling cycles and process parameters) are observed and it enables an option to reduce the need for virgin plastic.