Waste Polystyrene Research Articles

Upcycling of Polystyrene Waste to Poly(ionic liquid) Materials

Upcycling of Polystyrene Waste to Poly(ionic liquid) Materials

The Modification of Waste Polystyrene and Its Application as a Heavy Oil Flow Improver

The widespread use of polystyrene has brought great convenience to people's lives, but inappropriate recycling practices can also have a significant negative impact on the environment and public health. In this work, waste polystyrene was refined using maleic acid anhydride to produce flow improvers. The effect of the modified polystyrene perception of viscosity reduction and pour point depression of Henan oil was evaluated. The results show that modified polystyrene reduces the viscosity of Henan oil by 96.5% at most and depresses the pour point by 6.1 °C at most. Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1HH NMR) were used to investigate the modified polystyrene. The mechanism of modified polystyrene that improves the fluidity of heavy oil was proposed and analyzed through the study of wax crystal morphology (at 20 °C below the pour point).

Preliminary Research to Assess the Possibility of Grinding Selected Plastics Using Crushers

This study aims to investigate the effect of the shredding machine used on the recyclability of plastic fractions after primary crushing. This work presents a method for producing aggregates that has yet to be used in the plastics industry. This study included crushing of polymethylmethacrylate (PMMA), polyamide (PA-6), acrylonitrile butadiene-styrene (ABS), polycarbonate (PC), polystyrene (PS), and polypropylene (PP) waste in a jaw, a hammer, and a cone crusher. An analysis of the grain composition was carried out to characterize the obtained crushing products. The influence of feed size on the grain composition of the product and, only on the jaw crusher, the influence of the material used on the parameters of the crushing process was studied. This paper proposes a method to evaluate the grain composition and a way to assess plastic shredding capabilities based on machine kinematics and mechanical properties of a given material.

Modification mechanism of caking property of polystyrene waste using low-temperature pyrolysis and its use in coal-blending coking

Polystyrene (PS) waste was depolymerized using a low-temperature pyrolysis treatment (LTPT) to increase its caking index. The mechanism of caking index modification was revealed by using Fourier transform infrared spectroscopy, thermogravimetric (TG) analysis, pyrolysis-gas chromatography with mass spectrometric detection, and solid-state 13C nuclear magnetic resonance spectroscopy. The crucible coal-blending coking tests were carried out using an industrial coal mixture and the treated-PS with the highest caking index (PS300) or raw PS. Some properties of the resultant cokes were also analyzed. It was demonstrated that the caking index of PS dramatically increased by LTPT; however, exceeding 300 °C did not yield any benefit. The caking index increased due to the formation of the caking components, whose molecules are medium in size, caused by LTPT. Additionally, the coke reactivity index of the coke obtained from the mixture containing PS300 decreased by 5.1% relative to that of the coke made from the mixture with PS and the coke strength after reaction index of the former increased by 7.3% compared with that of the latter, suggesting that the ratio of depolymerized PS used for coal-blending coking could increase relative to that of PS.

Conversion of waste polystyrene into porous adsorbents for efficient removal of hazardous pollutants: Adsorption properties and adsorption mechanism

Herein, the porous adsorbent material (PS-SAS) was prepared by introducing a large number of carboxyl groups on the benzene ring of waste polystyrene (WPS) by Friedel-Crafts acylation reaction using succinic anhydride as the modifying group, followed by further alkaline modification, and was used for the removal of hazardous dye and heavy metal ion. The chemical structure and surface morphology of the prepared adsorbent were assessed via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), optical microscope (OM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The prepared adsorbent gave highly efficient separation performance towards malachite green (MG) and Cu2+ with corresponding maximum sorption capacities of 2231 mg/g and 156 mg/g at 298 K. The experimental data indicated that the sorption process followed the Langmuir adsorption isotherm and the pseudo-second-order kinetic model. Moreover, thermodynamic studies also demonstrated that the sorption process occurred spontaneously. The adsorption mechanisms of the adsorbent for MG include hydrogen bonding, electrostatic attraction, n-π interactions, and π-π interactions, while for Cu2+ via electrostatic attraction, ion exchange, and complexation. Furthermore, the selective adsorption, regeneration, dynamic sorption, and simulated wastewater experiment demonstrated that the adsorbent is a promising adsorbent. And phytotoxicity test proved that the prepared adsorbent can effectively reduce the toxicity of dye and metal ions. In summary, the transformation of waste polystyrene into an adsorbent represents a promising solution for water purification.

The high ductility performance of energy-absorbing buffer support materials

In order to study the realization of high ductility performance of foam fiber concrete (FFC) as energy-absorbing buffer support material, a series of samples were prepared based on the optimal mix ratio of orthogonal test. The uniaxial compression test was carried out to obtain the stress–strain curve and energy absorption curve. The strain capacity and macroscopic cracking process were revealed by digital image correlation (DIC). The mechanical performance of the admixture in the process of achieving high ductility performance was captured by scanning electron microscopy (SEM). The test results show that the average strength of FFC in the platform stage is 73.95% of the peak strength, and it can effectively absorb external energy as an energy-absorbing buffer support material. Foam, waste polystyrene particles and PVA fiber were the key factors to realize the high ductility of FFC.

Synthesis of porous hypercrosslinked polymers from waste polystyrene for efficient CO2 separation

A series of porous hypercrosslinked polymers (HCP-x) were synthesized from waste polystyrene foam via Fridel-Crafts alkylation reaction, aiming to optimize the utilization of waste plastics. The impact of various crosslinkers on the structural characteristics and CO2 adsorption properties of HCP-x was investigated. The results indicated that HCP-x polymers possess high specific surface areas spanning 830–1182 m2 g−1, abundant narrow micropores, and exceptional thermal stability. Notably, HCP-2 exhibited the highest CO2 adsorption capacity of 2.77 mmol g−1 at 273 K and 1.0 bar. These hypercrosslinked polymers also demonstrated a favorable CO2/N2 ideal selectivity and robust cyclic adsorption performance. Breakthrough experiments confirmed the selective adsorption of CO2 from simulated flue gas containing CO2/N2 (15/85). Additionally, the mechanism underlying CO2 adsorption on HCP-x was elucidated by analyzing adsorption thermodynamics and diffusion kinetics. This study not only introduces an innovative method for recycling waste polystyrene foam but also underscores the potential of HCP-x as an effective adsorbent for CO2 capture.

Performance enhancement of triboelectric nanogenerator by embedding tea-leaf powder in waste polystyrene

A triboelectric nanogenerator (TENG), which harvests electrical energy from ambient mechanical vibrations, has emerged as a potential alternative to battery for future energy autonomous sensors and wireless devices. In this paper, we report a very simple and cost-effective strategy to improve the performance of a waste-material-based triboelectric nanogenerator (TENG). Tea-leaf powder is used as the filler in waste polysyrene (WPS), derived from the waste packaging material by using a very simple process. TENGs are fabricated using the composite layer comprising varying concentrations of the tea-leaf powder in WPS (Tea@WPS) as the tribopositive layer and polytetrafluoroethylene (PTFE) as the tribonegative layer. It is found that a low concentration of the tea leaf powder, such as 5%, produces the best performance with a peak voltage of ~1800 V, a surface charge density of ~180 μC/m2, and a power density of 61.25W/m2, which are approximately 4.5×, 2.8×, and 8× higher than that for a similar TENG in which no tea-leaf filler is used in WPS. Possible reasons for such huge performance enhancement are discussed. Although the performance of the device is degraded when exposed to high humidity level, it is found that the device restores it original performance when the humidity is reduced again. No degradation of performance of the device is observed for over 110 days in the same ambient condition.

Structural and Functional Characteristics of the Anaerobic Microbial Community Emerging upon Its Contact with Extruded Polystyrene Waste

Structural and Functional Characteristics of the Anaerobic Microbial Community Emerging upon Its Contact with Extruded Polystyrene Waste

Machine learning based prediction of compressive and flexural strength of recycled plastic waste aggregate concrete

In the last 50 years, the use of plastics has increased significantly due to advances in technology, population growth and increasing needs. However, this trend has led to the accumulation of large amounts of plastic waste. Numerous studies have been conducted on the use of recycled plastic materials in concrete production as a means of recycling and environmental protection. This study aims to predict the 28-day cylinder compressive and flexural strength of concretes using Polyethylene Terephthalate (PET), Phenolic Formaldehyde (PF), Polypropylene (PP), Polycarbonate (PC), Polyvinyl Chloride (PCV), High-Impact Polystyrene (HIPS) and High-Density Polyethylene (HDPE) plastic waste as aggregates. In this scope, a comprehensive database was created using experimental results obtained from the literature. Then, this study used six ML models, including Support Vector Regressor (SVR), Random Forest Regressor (RFR), Gradient Boosting Regressor (GBR), XGBoost Regressor (XGR), LightGBM Regressor (LGR), Bagged Decision Trees Regressor (BDTR), to predict the compressive and flexural strength of recycled plastic waste aggregate concrete (RPWAC). From the experimental database, 253 data points with strength between 6.00–70.05 MPa were identified to estimate the compressive strength (CS) and 175 data points with strength between 1.21–7.96 MPa were identified for flexural strength (FS). Cross-validation was used for six ML models and hyperparameter fine-tuning was performed. The results showed that six different ML models predicted the compressive and flexural strengths of RPWAC with high accuracy. The XGR model predicted CS and FS better than the other five different models with R2 values of 0.931 and 0.999, respectively. The three main properties effecting the CS of RPWAC were plastic waste content, water/cement ratio and concrete specific gravity, while the three main properties affecting the FS of RPWAC were cement specific gravity, plastic waste content and cement CS.

High-Sulfur-Content Materials Derived from Postconsumer Polystyrene Wastes: Thermomechanical Properties, Environmental Impacts, and Microstructural Insights

High-Sulfur-Content Materials Derived from Postconsumer Polystyrene Wastes: Thermomechanical Properties, Environmental Impacts, and Microstructural Insights

Studies on particleboard production using Expanded Polystyrene (EPS) waste as a binder for construction applications

This study explored the potential of using EPS waste as a substitute for synthetic resin in particleboard production. The objectives were to assess the impact of various processing parameters, including board density, EPS waste percentage, and pressing temperature, on the properties of the board. For this purpose, lab-scale particleboards were fabricated by combining kelempayan wood particles with EPS waste powders. Subsequently, the physical, mechanical, and thermal stability properties of the board were assessed. The results indicated that the board density, EPS waste percentage, and pressing temperature influenced the physical, mechanical, and thermal stability properties of the board. The bending properties, internal bond (IB) strength, and thickness swelling (TS) of the board exhibited an upward trend with increasing board density. At the same time, the TS decreased while bending properties and IB strength increased with rising EPS waste percentages and pressing temperatures. Notably, the board fabricated with a target density of 0.70 g/cm3, comprising 20 % EPS waste and pressed at 180°C, met the standard requirements for particleboard designated for construction purposes, except the modulus of rupture (MOR), which is slightly lower than the standard requirement. In addition, the thermal stability of the board increased with higher pressing temperatures. Conversely, increasing the density and EPS waste percentage to 40 % appeared to decrease the thermal stability of the board. These findings underscore the significant potential of EPS waste as a binder in particleboard production.

Towards enhanced monocyclic aromatic hydrocarbons production from Co-pyrolysis of biomass and waste polystyrene plastic

Co-pyrolysis technology offers a viable solution for utilizing biomass and waste plastics as a valuable energy resource, to support waste management, energy supply and environmental protection. In this paper, co-pyrolysis of poplar tree (PT) and polystyrene (PS) at mixture ratios of 0:1, 3:1, 2:1, 1:1, 1:2, 1:3 and 1:0 under different pyrolysis temperatures (450, 550, 650, and 700 °C), using different catalysts (HZSM-5, MCM-41, Fe/HZSM-5, and Cu/HZSM-5) were investigated using gas chromatography/mass spectrometry (Py-GC/MS) diagnostics for determining products distribution and synergistic effects. The results showed that PT performed best at a pyrolysis temperature of 650 °C, whereas PS performed best at 550 °C. The relative amount of aromatics in the co-pyrolysis products of PT and PS was highest at 550 °C that showed positive synergistic effects. The synergistic effects from the co-pyrolysis of PT and PS were significantly different at different mixture ratios of the PT and PS feedstocks. At mixture ratios of 1:1 and 1:2, the relative amounts of polycyclic aromatic hydrocarbons (PAHs) and monocyclic aromatic hydrocarbons (MAH) were higher and showed positive synergistic effects. The catalysts promoted the generation of MAH and inhibited the PAHs formation in the co-pyrolysis. The Fe/HZSM-5 catalyst provided the most significant effect on MAH showing the highest relative amounts. The results showed that highest yield of monocyclic aromatic hydrocarbons can be achieved from the pyrolysis of PT and PS materials at 1:1 mixture ratio using Fe/HZSM-5 catalyst, at a reaction temperature of 550 °C.

Unification of thermal conductivity, electrical insulation, and electromagnetic shielding: A bulk thermal conductive polymer from solid waste

In the context of the ongoing advancements in high-performance chips, heat dissipation, and electromagnetic shielding within electrical and electronic equipment are becoming increasingly intricate. Plastics have garnered widespread usage in electrical and electronic equipment as prevalent framework materials. However, the challenge persists in achieving a unification of electromagnetic interference (EMI) shielding, thermal conductivity (TC), and electrical insulation performance for plastics. Herein, we capitalize on the styrene–butadiene–styrene (SBS) copolymer to integrate the merits of polymers and magnetic minerals. Utilizing pyrrhotite (Pyr) tailings and waste polystyrene (PS) as raw materials, a formable block material denoted as PS-S@SBS/Pyr has been formulated. This material exhibits commendable performance in terms of TC, electrical insulation, and EMI shielding performance concurrently. The bidirectional bridging effect of SBS effectively reduces the interfacial thermal resistance between PS and Pyr. The TC of PS-S@SBS/Pyr can reach a maximum of 1.36 W/m‧K with a resistivity greater than 108 Ω‧m. Moreover, PS-S@SBS/Pyr consistently demonstrates a stable EMI shielding effectiveness of 33.1 dB within the 8–12 GHz frequency range, with absorption shielding predominating as the underlying mechanism. This green preparation method makes efficient utilization of two main solid wastes while increasing the added value of the material.

Thermochemical recycling of polystyrene waste by pyrolysis using a pilot-scale auger reactor: Process demonstration in a relevant environment

This study presents the pyrolysis of polystyrene waste using a single-auger pyrolysis reactor at an industrially relevant scale, i.e. within the fifth technology readiness level (TRL-5). In order to gain a better understanding of the influence of the main variables involved in this technology, a thorough experimental campaign was performed with PS feed rates of 6 and 9 kg/h, covering a temperature range of 450–600 °C. These variables influence not only the distribution of the products, but also the presence of compounds that may affect the suitability of the pyro-oil for re-polymerisation processes. In this sense, gas chromatography (GC), gas chromatography coupled to mass spectrometry (GC/MS) and simulated distillation (SimDist) of the resulting pyro-oils provided valuable insights into styrene purification. The data collected confirms the strength of the auger reactor for thermochemical recycling of polystyrene waste, and contributes to the future development of the plastics circularity on an industrial scale.

Eco-Friendly Highways: Harnessing Waste Polystyrene and Reclaimed Asphalt Pavement for Sustainable Roadways and Environmental Mitigation

Eco-Friendly Highways: Harnessing Waste Polystyrene and Reclaimed Asphalt Pavement for Sustainable Roadways and Environmental Mitigation

Sustainable conversion of polystyrene waste into polymeric surfactants to be evaluated as pour point deperssants for waxy crude oil

Disposing of polystyrene trash is an environmental concern, and converting it into value-added products is appealing . This research study focuses on implementing a sustainable method to convert polystyrene waste into polymeric nonionic surfactants. The polymeric nonionic surfactant additives were prepared by grafting polystyrene waste (WPS) with a methacrylic monomer (MMA), followed by an esterification reaction with polyethylene glycol of different molecular weights (400 and 1000). The chemical composition of the synthesized compounds was justified by spectroscopic analysis. Interfacial tension (IFT) was investigated to gain insights into the behavior of the polymeric nonionic surfactants produced at the interface. The modified waste polymers were evaluated as pour depressants and paraffin inhibitors. Additionally, the rheological properties of the modified waste polymers were examined. The findings revealed that, the IFT between oil and water decreased from 21 to 7 mN/m for WSPA400 and even further to 4 mN/m for WSPA1000. At a concentration of 500 ppm, WPSA1000 exhibited the maximum depression effect than WPSA400, reducing the pour point temperature from 27 °C to 12 °C and 3 °C, respectively. Also, At 500 ppm, the amount of wax deposition declined from 8.5 g to 1.90 g and 0.95 g after treating the crude oil with WPSA 400 and WPSA 1000. The rheological measurements further revealed that the WPSA1000 additive outperformed the WPSA400 additive in terms of enhancing the fluidity of oil. In order to acquire a more comprehensive understanding of the mechanisms involved in pour point depression, the utilization of polarizing optical microscopy was used to explore the effect of WPSA1000 as a pour point depressant.

Valorizing polymeric wastes and biomass through optimized co-pyrolysis for upgraded pyrolysis oil: A study on TG-FTIR and fixed bed reactor

The co-pyrolysis of biomass and polymeric wastes offers a promising approach for waste reduction and valuable product recovery while decreasing fossil fuel dependence. This study aimed to investigate the synergistic effects of blending waste tire (WT) or polystyrene (PS) with sawdust (SD) at varying effective hydrogen/carbon ratio (H/Ceff) on liquid product distribution. Thermal degradation behavior was analyzed using TGA-FTIR, followed by fixed-bed reactor pyrolysis experiments at different temperatures. The devolatilization of SD primarily occurred between 185 and 390°C, while WT and PS decomposed between 250 and 500°C and 350–460°C, respectively. Results showed that SD addition to WT accelerated degradation at lower temperatures. Optimal H/Ceff ratios were 0.42 for WT/SD and 0.64 for PS/SD blends at 500°C, maximizing valued hydrocarbons, reducing pollutants, and yielding the highest liquid fraction. TGA-FTIR analysis revealed the presence of various functional groups, including C-H, CC, CO2, and O-H. The pyrolytic oil showed improved stability with significantly fewer undesired compounds. This research provides theoretical and practical insights into the control and application potential as well as the limitations of high-value energy products derived from the co-pyrolysis of SD, WT, and PS.

Pyrolysis of polystyrene using low-cost natural catalysts: Production and characterisation of styrene-rich pyro-oils

This work aims to study the catalytic pyrolysis of polystyrene (PS) in order to obtain a styrene-rich liquid appealing for re-polymerisation processes. The process was performed in a fixed-bed reactor using low-cost materials such as ilmenite, olivine, calcium oxide (CaO) and dolomite as catalysts at 600 ºC. A non-catalytic test with sand was also conducted for comparison purposes. The resulting pyro-oil yield was between 89 and 96 wt%, and consisted mainly of styrene monomer, styrene dimer and styrene trimer, as well as other light aromatic compounds depending on the catalyst used. Olivine and CaO were capable to increase the styrene monomer concentration in the pyro-oil by about 10–12 % compared to non-catalytic pyrolysis, reaching up to 74.5 and 71.4 wt%, respectively. Furthermore, these catalysts reduced the concentration of styrene dimer and styrene trimer in the pyro-oil, which could be useful for further re-polymerisation processes. However, the presence of polyaromatics (PAHs) in the pyro-oils obtained from ilmenite, olivine and CaO was also identified, and other families such as mono-aromatics, di-aromatics, BTX, and nitrogen heterocyclic compounds were also increased in all pyro-oils obtained with catalysts compared to those obtained by non-catalytic pyrolysis. In addition, several inorganic species in the pyro-oil were reduced by the addition of the catalysts. This effect was observed after the addition of olivine and CaO, especially in the reduction of S, Mg, Ca and Fe. These results clearly demonstrate the potential of pyrolysis to convert PS waste into valuable building blocks for the production of new plastics.

Environmental protection and sustainable waste-to-energy scheme through plastic waste gasification in a combined heat and power system

By utilizing plastic waste as a feedstock for gasification and integrating a solid oxide fuel cell, this system has the potential to not only generate electricity and heat efficiently but also reduce environmental pollution by converting waste materials into valuable energy resources. This research explores a combined heat and power system that integrates polystyrene waste gasification with a solid oxide fuel cell technology. The study thoroughly examines and optimizes the system's performance through the application of response surface methodology. Higher steam to plastic waste ratio improves the power production (from 244.1 to 246 kW) and mitigates the emission (from 785.4 to 761.3 kg/MWs). Enhanced power (from 86.25 to 337 kW, representing an impressive improvement of approximately 291 %) and heating (from 172.6 to 275.3 kW, marking a substantial improvement of approximately 59.5 %) are achieved at higher current densities. At a current density of 3200–3600 A/m² and a temperature of 1020–1040 K, the system can achieve 200–240 kW power, 390–450 g/s heating value, and 840–860 kg/MWs emissions. Further optimization at a steam to plastic ratio of 0.95–1.1 and 1030–1040 K temperature can improve performance to 280–300 kW power, 580–600 g/s heating value, and 840–860 kg/MWs emissions. The study provides valuable insights into the potential benefits of integrating plastic waste gasification with solid oxide fuel cell technology, highlighting the importance of sustainable energy solutions in addressing environmental challenges. Moving forward, further research in this area could lead to the development of more efficient and environmentally friendly energy systems.