Closing the loop for PET, PE and PP waste from households: Influence of material properties and product design for plastic recycling

Critical properties of plastic packaging waste for recycling: A case study on non-beverage plastic bottles in an urban MSW system in Austria

The low recycling rate of post-consumer plastic packaging waste (PPW), which is partly due to insufficient separate collection, heterogeneous composition and high levels of contamination, poses a challenge in Austria, where the recycling rate must double in order to meet the target of 55 %. This study analyzes key packaging characteristics of non-beverage plastic bottles influencing recyclability, using Vienna as a case study. Additionally, a net quantity indicator and separate collection rates were calculated. 738 bottles from mixed MSW and 1,159 bottles from separate PPW collection were analyzed. The main polymer's proportion described by the net quantity indicator was higher for bottles from separate collection (69-72 %) than from mixed MSW (58 %), showing that a large share of the foreign materials are residues and dirt, with significantly higher contents in mixed MSW (20 %) than in separate collection (11 %). With a separate collection rate of 19.2 %, the great potential for recycling currently lies in mixed MSW at 4,112 t/yr. Thereof, 46 % is uncolored, 54 % is colored/white and, in terms of material grade, 30 % is food grade. The most common filling volume for PET, PP and HDPE was 0.5 < x ≤ 1.5 L (23-59 %) and the most common decoration technology was label (60-85 %). PET and PP had the highest shares of food-grade bottles (37-46 %), while PP had the highest share of colored bottles (22-31 %). The mechanical recycling potential of bottles depends largely on packaging characteristics, influencing separate collection and also automatic sorting. Harmonized design specifications are therefore crucial for this heterogeneous PPW fraction.

Parameters optimization for decontamination and fine physical regeneration pathways of polypropylene plastics from waste lunchboxes

Due to the development of the food delivery industry, a large amount of waste lunchboxes made of homo polypropylene (PP) plastic have been generated. This study developed a new technological strategy to effectively regenerate PP from waste lunchboxes. Through response surface curve analysis, it was found that under the optimal process conditions of hot alkali washing at 80 ℃, 30 min, and pH 13, the optimal contact angle was 65.55°, indicating a good oil stain removal effect. By identifying and analyzing the characteristics of impurities in waste lunchboxes, a physical sorting and granulation regeneration process was constructed. And through large-scale statistical analysis and data collection, it was further verified that recycled PP plastics maintained their physical stability and excellent processing performance. The quality stability of recycled PP plastics in terms of impurities content was also verified. By designing different formulations specifically, recycled PP was mixed with different virgin PP and antioxidants in appropriate proportions, and extruded into particles under 150-300 mesh filtration conditions to obtain modified recycled PP. Modified recycled PP was applied in textiles, clothing, and injection molded products. In conclusion, we achieve the up-cylcing of waste PP lunchboxes instead of down-cylcing.

Depolymerization within a Circular Plastics System

The societal importance of plastics contrasts with the carelessness with which they are disposed. Their superlative properties lead to economic and environmental efficiency, but the linearity of plastics puts the climate, human health, and global ecosystems at risk. Recycling is fundamental to transitioning this linear model into a more sustainable, circular economy. Among recycling technologies, chemical depolymerization offers a route to virgin quality recycled plastics, especially when valorizing complex waste streams poorly served by mechanical methods. However, chemical depolymerization exists in a complex and interlinked system of end-of-life fates, with the complementarity of each approach key to environmental, economic, and societal sustainability. This review explores the recent progress made into the depolymerization of five commercial polymers: poly(ethylene terephthalate), polycarbonates, polyamides, aliphatic polyesters, and polyurethanes. Attention is paid not only to the catalytic technologies used to enhance depolymerization efficiencies but also to the interrelationship with other recycling technologies and to the systemic constraints imposed by a global economy. Novel polymers, designed for chemical depolymerization, are also concisely reviewed in terms of their underlying chemistry and potential for integration with current plastic systems.

Integrated analytical hierarchy process-grey relational analysis approach for mechanical recycling scenarios of plastics waste in India

Mechanical recycling is an indispensable tool for plastic waste (PW) recycling and has the highest share in the PW recycling sector in India. The transition to the circular economy of plastics (CEoP) needs a systemic perspective on the mechanical recycling processes. Nevertheless, the assessment of multiple parameters influencing the mechanical recycling of PW is a complex decision-making problem for the development of triple-bottom-line mechanical recycling. A systemic perspective of various mechanical recycling scenarios was performed by employing a multi-criteria decision-making approach to examine the complexity of interlinked factors in the present investigation. Analytical hierarchy process (AHP) integrated with grey relational analysis (GRA) was used to evaluate the criteria that directly influence quality-oriented mechanical recycling. Data were collected by conducting semi-structured interviews using a framed questionnaire in stakeholder engagement with mechanical recyclers of PW. The first level hierarchy included economy, technical, resource consumption and environmental criteria. These criteria were further categorized into various significant indices such as quality of recyclate, recyclability, water and energy consumption during recycling. The results of the integrated grey relational analysis indicated that the technical parameters including quality of recyclate, resource efficiency, PW processing rate and recyclability have a significant influence on mechanical recycling. Based on AHP-GRA, scenario MR6, i.e. manufacturing of PET strap from recycled PET flakes, was ranked the optimal mechanical process amongst the various scenarios. MR6 was followed by Straps and Films at the second and third rank. The lowest ranking was observed for polymer blend recycling. These processes with higher ranks produced good quality recyclate with better efficiency and recyclability. Moreover, these processes consumed optimal resources during manufacturing. These processes also exhibited less maintenance cost, high production rate, low chemical consumption and waste generation as well as implemented pollution control practices.

Complementary roles for mechanical and solvent-based recycling in low-carbon, circular polypropylene

Plastic recycling presents a vexing challenge. Mechanical recycling offers substantial greenhouse gas emissions savings relative to virgin plastic production but suffers from degraded aesthetic and mechanical properties. Polypropylene, one of the most widely used and lowest-cost plastics, features methyl pendants along the polymer backbone, rendering it particularly susceptible to declining properties, performance, and aesthetics across a succession of mechanical recycles. Advanced processes, such as solvent-assisted recycling, promise near-virgin quality outputs at a greater energy and emissions footprint. Mechanical and advanced recycling are often presented as competing options, but real-world plastic waste streams are likely to require preprocessing regardless of whether they are routed to an advanced process. This study quantifies the life-cycle greenhouse gas implications of multiple recycling strategies and proposes a system in which mechanical and solvent-assisted recycling can be leveraged together to boost recycling rates and satisfy demand for a wider range of product applications. Polypropylene can be recovered from mixed-plastic bales produced at material recovery facilities and processed through mechanical recycling, with a varying fraction sent for further upgrading via solvent-assisted recycling to produce material approved for food packaging and other higher-quality applications. The resulting mechanically recycled rigid polypropylene reduces life-cycle greenhouse gas emissions by 80% relative to the same quantity of virgin material, while the upgraded higher-quality material achieves GHG savings of 30%.

Does PET trays sorting affect the sustainability of plastic waste? An LCA and cost-revenue approach

Currently, the management of polyethylene terephthalate (PET) trays waste is still challenging since this packaging affects the consolidate recycling of PET bottles. It is important to separate PET trays from the PET bottle waste stream to avoid its contamination during recycling process and to recover a higher amount of PET. Hence, the present study aims to evaluate the environmental (by means of Life Cycle Assessment, LCA) and economic sustainability of sorting PET trays from the plastic waste streams selected by a Material Recovery Facility (MRF). For this scope, the case of a MRF in Molfetta (Southern Italy) was chosen as reference, and different scenarios have been evaluated by assuming different schemes of manual and/or automated PET trays sorting. The alternative scenarios did not achieve very pronounced environmental benefits over the reference case. Upgraded scenarios resulted in overall environmental impacts approx. 10 % lower as compared to the current scenario, with the exception of the climate and ozone depletion categories where differences in impacts were much higher. From an economic point of view, the upgraded scenarios achieved slightly lower costs (<2 %) than the current one. Electricity or labour costs were necessary in upgraded scenarios, but in this way fines for PET trays contamination in PET streams for recycling were avoided. Implementing any of the technology upgrade scenarios is then environmentally and economically viable, when the PET sorting scheme is performed in appropriate output streams through optical sorting.

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.

Research on the Development of a Way to Modify Asphalt Mixtures with PET Recyclates

Due to the growing need to recycle plastics, new possibilities for their reuse are intensively sought. In the Asian market, waste polymers are increasingly used to modify road bitumen. This solution is beneficial in many aspects, especially in economic and ecological terms. In this work, recycled poly(ethylene terephthalate) (RPET), obtained from storage points located in Lesser Poland, was subjected to material recycling, and its properties were examined using three analyses: differential scanning calorimetry (DSC), thermogravimetric analysis (TG), and Fourier transform infrared spectroscopy (FTIR). The most important point of this research was the selection of conditions for obtaining modified asphalt mixtures through the addition of RPET. Subsequently, the effect of the polymer on the properties of road bitumens was assessed on the basis of penetration tests, softening point, elastic recovery, and structure. In the last stage of our research work, asphalt mixtures with the addition of modified waste PET (PMA) containing mineral filler in the form of basalt dust were obtained. The properties of the obtained mineral-polymer-asphalt mixtures were compared in terms of frost resistance, structure, and abrasion resistance with the properties of mineral-asphalt mixtures that were taken from damaged road surfaces in four points in the city of Tarnów (Lesser Poland) in the winter of 2022. It has been shown that the modification of road bitumen with the use of recyclate and mineral filler has a significant impact on its performance properties.

Evaluation of mixed #3-7 plastic waste from material recovery facilities (MRFs) in the United States

Plastic recycling rates are still low in the United States (U.S.), with less than 10% of municipal solid waste (MSW) plastic being recycled. Most unrecycled plastics are identified by Resin Identification Codes (RIC) from #3-7, which are commonly destined for landfill or waste-to-energy facilities (WTE). Therefore, the composition and quality of outbound bales containing #3-7 plastics were assessed to understand the potential to increase recycling rates. Three bales were sourced from three different Material Recovery Facilities (MRFs) located in the United States. Each bale was manually sorted and characterized for quality and performance via multiple plastic characterization techniques. Considerable differences in bale composition were observed between MRFs, which correlated with the technology used by each MRF in the sorting process. The differences were substantial in the residual levels of poly(ethylene terephthalate) (PET) and high-density polyethylene (HDPE), which are highly desired for mechanical recycling processes and not expected in #3-7 plastics bales. Traditional recycling processes including washing, extrusion, and injection molding of the sorted material were employed prior to the physical, thermal, and molecular characterization. Despite differences in bale composition by plastic type, some polymer properties were similar across MRFs. This research suggests that landfill-diverted mixed plastic waste can be utilized in the mechanical recycling of currently unrecycled materials, as processes can be designed to work with consistent polymer properties. It also highlights the need to upgrade the sorting systems to prevent waste feedstocks, which can be recycled with current technologies, from contaminating other plastic streams or reach landfills.

Suitability of MRF Recovered Post-Consumer Polypropylene Applications in Extrusion Blow Molded Bottle Food Packaging

Polypropylene (PP) is one of the most abundant plastics used due to its low price, moldability, temperature and chemical resistance, and outstanding mechanical properties. Consequently, waste from plastic materials is anticipated to rapidly increase with continually increasing demand. When addressing the global problem of solid waste generation, post-consumer recycled materials are encouraged for use in new consumer and industrial products. As a result, the demand is projected to grow in the next several years. In this study, material recovery facility (MRF)-recovered post-consumer PP was utilized to determine its suitability for extrusion blow molded bottle food packaging. PP was sorted and removed from mixed-polymer MRF-recovered bales, ground, trommel-washed, then washed following the Association of Plastics Recyclers' protocols. The washed PCR-PP flake was pelletized then manually blended with virgin PP resin at 25%, 50%, 75, and 100% PCR-PP concentrations and fed into the extrusion blow molding (EBM) machine. The EBM bottles were then tested for physical performance and regulatory compliance (limits of TPCH: 100 μg/g). The results showed an increased crystallization temperature but no practical difference in crystallinity as a function of PCR-PP concentrations. Barrier properties (oxygen and water vapor) remained relatively constant except for 100% MRF-recovered PCR-PP, which was higher for both gas types. Stiffness significantly improved in bottles with PCR-PP (p-value < 0.05). In addition, a wider range of N/IAS was detected in PCR-PP due to plastic additives, food additives, and degradation byproducts. Lastly, targeted phthalates did not exceed the limits of TPCH, and trace levels of BPA were detected in the MRF PCR-PP. Furthermore, the study's results provide critical information on the use of MRF recovered in food packaging applications without compromising performance integrity.

Effects of Circularity Interventions in the European Plastic Packaging Sector

Low levels of plastics circularity today reflect major challenges for the sector to reduce environmental impacts and a need for wider systemic change. In this work, we investigated the potential for climate and socioeconomic benefits of circular economy (CE) interventions in the plastic packaging system. By means of a mixed-unit input-output (IO) model, we performed a comparative scenario analysis for the development of demand and waste management up to 2030 within the EU-28 (EU27 + United Kingdom). We modeled the development of material flows and assessed the effects of both demand-side and end-of-life interventions. Different levels of ambition toward 2030 based on EU circular economy strategies were tested. Results showed that on reaching high levels of circularity, between 14 and 22 Mt CO₂-eq/year could be reduced by 2030 (20-30% of the total sector impact in 2018) compared to business-as-usual. Demand change (e.g., by decreasing product packaging intensities) showed similar emission-saving potential as achieving the current recycling target of 55%, which emphasizes the role of demand-side actions. Most scenarios displayed moderate employment gains and potential economic losses, pertaining to both direct and indirect activity shifts in the economy. While considering model limitations, the approach is useful in indicating potential first-order effects of system changes.

Perspectives on Thermochemical Recycling of End-of-Life Plastic Wastes to Alternative Fuels

Due to its resistance to natural degradation and decomposition, plastic debris perseveres in the environment for centuries. As a lucrative material for packing industries and consumer products, plastics have become one of the major components of municipal solid waste today. The recycling of plastics is becoming difficult due to a lack of resource recovery facilities and a lack of efficient technologies to separate plastics from mixed solid waste streams. This has made oceans the hotspot for the dispersion and accumulation of plastic residues beyond landfills. This article reviews the sources, geographical occurrence, characteristics and recyclability of different types of plastic waste. This article presents a comprehensive summary of promising thermochemical technologies, such as pyrolysis, liquefaction and gasification, for the conversion of single-use plastic wastes to clean fuels. The operating principles, drivers and barriers for plastic-to-fuel technologies via pyrolysis (non-catalytic, catalytic, microwave and plasma), as well as liquefaction and gasification, are thoroughly discussed. Thermochemical co-processing of plastics with other organic waste biomass to produce high-quality fuel and energy products is also elaborated upon. Through this state-of-the-art review, it is suggested that, by investing in the research and development of thermochemical recycling technologies, one of the most pragmatic issues today, i.e., plastics waste management, can be sustainably addressed with a greater worldwide impact.

What potential does the EU Single-Use Plastics Directive have for reducing plastic pollution at coastlines and riversides? An evaluation based on citizen science data

To address environmental pollution by plastic litter, the European Union adopted EU Directive 2019/904, the so called "Single-Use Plastics Directive" (SUPD), which bans several single-use plastic products and addresses additional items with measures such as extended producer responsibility and obligatory requirements for product redesign. This study assessed the potential of the SUPD to reduce litter pollution in the environment with three scenarios. The "best case" scenario assumed that all measures of the SUPD completely prevent targeted items from getting into the environment. Another scenario assumed that no measures besides bans were effective. An intermediate scenario assumed partial effectiveness of measures. Data of almost 5,000 sampling events from citizen science protocols (Plastic Pirates, International Coastal Cleanup, Marine Litter Watch) and the OSPAR protocol were used to analyse litter at riversides and coastlines in Germany and the European Union. 44 to 68% of litter items in citizen science protocols consisted of single-use plastics (cigarette butts were the most prominent items). At coastlines sampled by the OSPAR protocol, fishing gear and undefined plastics prevailed. The scenario analysis revealed that substantial litter reductions could be achieved in the "best case" scenario (upwards of 40%), while the intermediate scenario resulted in litter reductions of 13 to 25%. The marginal effect of the "only bans" scenario achieved a reduction of 2-6% in Germany and the European Union, respectively. Thus, depending on implementation and enforcement, the current SUPD can be an important first step, yet further legislative actions are needed to effectively prevent plastic waste pollution.

Recycled PMMA prepared directly from crude MMA obtained from thermal depolymerization of mixed PMMA waste

Recycled PMMA was prepared by directly polymerizing crude pyrolysis oils from lab-scale pyrolysis of collected industrial waste PMMA. The pyrolysis oils consisted mainly of methyl methacrylate (MMA, >85%), while the type and number of by-products from the thermal process were assigned through GC-MS analysis showing a clear correlation to the pyrolysis temperature. By-products can be removed by distillation; however, directly employing the crude oils to prepare PMMA through solution, suspension, emulsion, or casting polymerization was investigated to assess the potential for omitting this costly step. It was found that the crude pyrolysis oils could be polymerized efficiently via solution, emulsion, and casting polymerization to produce a polymer similar to the PMMA prepared from a pristine monomer. The impurities in the PMMAs prepared from the crude mixtures were investigated by extraction analyses followed by screening by GC-MS. In the case of casting polymerization, the GC-MS analysis, as expected, revealed various residual by-products, while solution and emulsion polymerization showed only very few impurities, mainly originating from the polymerization and not the feed material. Additional purification of the crude pyrolysis oils would be required for applications in casting polymerization. In contrast, direct polymerization by emulsion or solution polymerization is considered applicable for producing pristine PMMA from crude waste PMMA pyrolysis oil.

Green finance in circular economy: a literature review

Developing markets are using sustainable development potential to reach zero-carbon goals. Due to the limitation of natural resources, companies need to use environmentally friendly manufacturing to develop a circular economy (CE). Green finance (GF) and the CE are linked in a systematic and complex approach; therefore, it was essential to employ the coupling coordination-level framework to explain their relationship and feedback. Any study linking green financing and CE together has been found. The objective of this research is to explore this twofold domain and determine its main characteristics. To address this objective, a comprehensive review of the literature was conducted, supplemented by a bibliometric analysis. The results confirm that GF has the potential to help society, sustainability, and the prevention to climate shifts, investing in the CE. There are many hurdles to overcome, including inadequate knowledge about CE and GF, ambiguous definitions, a lack of coherence between legal frameworks on CE and green financing, unclear laws, and a lack of financially viable motivation for investors and financial institutions that are ready to promote in sustainability. This study explores CE and GF domains. Managers may readily increase their understanding of methods, strategies, and technical solutions beneficial to assist their operations toward a green economy depending on various CE and GF elements. Finally, based on a categorization of GF types, the assessment identifies future investment potential consequences of green financing in the CE.

Preparation of Waste PP/Fly Ash/Waste Stone Powder Composites and Evaluation of Their Mechanical Properties

The research was carried out to analyze the combined and mechanical properties of polypropylene (PP)/fly ash (FA)/waste stone powder (WSP) composite materials. PP, FA and WSP were mixed and prepared into PP100 (pure PP), PP90 (90 wt% PP + 5 wt% FA + 5 wt% WSP), PP80 (80 wt% PP + 10 wt% FA + 10 wt% WSP), PP70 (70 wt% PP + 15 wt% FA + 15 wt% WSP), PP60 (60 wt% PP + 20 wt% FA + 20 wt% WSP) and PP50 (50 wt% PP + 25 wt% FA + 25 wt% WSP) composite materials using an injection molding machine. The research results indicate that all PP/FA/WSP composite materials can be prepared through the injection molding process and there are no cracks or fractures found on the surface of the composite materials. The research results of thermogravimetric analysis are consistent with expectations, indicating that the preparation method of the composite materials in this study is reliable. Although the addition of FA and WSP powder cannot increase the tensile strength, it is very helpful to improve the bending strength and notched impact energy. Especially for notched impact energy, the addition of FA and WSP results in an increase in the notched impact energy of all PP/FA/WSP composite materials by 14.58-22.22%. This study provides a new direction for the reuse of various waste resources. Moreover, based on the excellent bending strength and notched impact energy, the PP/FA/WSP composite materials have great application potential in the composite plastic industry, artificial stone, floor tiles and other industries in the future.

Evaluating the collection and composition of plastic waste in the digital waste bank and the reduction of potential leakage into the ocean

Most ocean plastic pollution results from leakage from waste management activities on land, mainly in coastline communities. In this research, the digitalization of waste management will be evaluated to improve the prevention of leakage. The digitalization means introducing mobile apps into the waste bank that can improve waste management efficiency while providing reliable data. The data on waste management were gained from Griya Luhu App which has been used in 13 villages around Gianyar, while the waste generation was calculated from 97 samples. Then, the villages were categorized by their potential risk of waste leakage based on their distances from the shore. First, the growth of digital waste banks based on the number of units, the number of customers and the amount of waste-managed was analyzed. Second, the composition of waste collected was evaluated. Last, inorganic waste generation (IWG) from digital waste banks was reduced. The results showed that digital waste banks and the customers had grown rapidly in 1 year. The number of waste bank units grew from 0 to 80 with an increase to a total of 5500 customers during the same period with a maximum of 20 tons of waste managed per month. In general, digital waste banks have shown promising performance in preventing waste leakage into the ocean with a 54.04% reduction of IWG. Compared to this reduction percentage, Tulikup as a high-risk village has a considerably low reduction (30.30%) and should be prioritized. Furthermore, the ability to manage a village with a high population/number of customers should be improved.

Exploring the Surface Potential of Recycled Polyethylene Terephthalate Composite Supports on the Collagen Contamination Level

With a significant number of features (namely being multipurpose, inexpensive and durable), thermoplastic polymers, most often named plastics, are part of our daily routine, with an increasing production over the last decade. Among them, polyethylene terephthalate (PET), high-density polyethylene (HDPE) and polypropylene (PP) are distinguished as the five most commonly used plastics in various fields, mainly in the packaging industry. Even if it is difficult to imagine the world without plastics, the boosted plastic assembly comes with huge plastic waste, creating a number of challenges, as the most important threat for our environment, but also opportunities for recycling. Currently, a special attention is dedicated on how to improve the current recycling methods or to find new ones, since the quality of recycled plastics and potential chemical or biological contaminations are two problematic aspects. Understanding the properties of each thermoplastic polymer and the interaction with possible contaminants may be the key for an efficient recycling process. The aim of this paper was to evaluate the surface behaviour of different composite supports based on recycled PET before and after interaction with collagen (used as a biological contaminant). The surface contamination bias of PET supports was studied through different techniques: scanning electron microscopy (SEM), water uptake through swelling studies, contact angle measurements and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR).

Assessment of the Impact of Superficial Contamination and Thermo-Oxidative Degradation on the Properties of Post-Consumer Recycled Polypropylene

Single-use plastics are a matter of convenience in everyday life, with the majority allocated to packaging production. However, it comes with a high environmental price as its mass recycling is challenging due to the heterogeneity of composition, contaminations of different kinds, and degradation caused by service and processing. This study aims to ascertain the impact of removing contaminants from post-consumer recycled polypropylene (rPP) on its degradation and properties by implementing a systematic approach for decontamination by washing. Four lots of recycled plastics with different degrees of contamination were evaluated via Fourier transform infrared, melt flow indexer, and differential scanning calorimetry and tested for tensile strength. Degradation of the rPP was manifested by the deterioration in ductility, resulting in 14.58% elongation at break (unwashed rPP) compared with 191.41% (virgin PP)) and a significant reduction in oxidation induction time. In the unwashed rPP sample, a wave intensity peak at 1730 cm^-1, assigned to the saturated C = 0 stretch of the carbonyl functional group, was detected. This peak was gradually disappearing with an increase in the cleaning efficiency of rPP, highlighting the role of contaminants as degradation catalysts. The cold-washing method showed similar processing and mechanical performance improvement results compared with the other washing methods, while being more environmentally friendly and energy efficient.

Mechanical and Thermal Properties of Mixed PE Fractions from Post-Consumer Plastic Packaging Waste

The functional properties of recycled post-consumer flexible polyethylene packaging waste have been studied using materials collected and sorted at a large-scale facility in Sweden. The studied fraction was used both as received and after simple laboratory washing in water with added sodium hydroxide at 40 °C. The materials were melt-compounded with a twin-screw extruder using two different temperature profiles and two screw configurations and injection-molded into slabs, whose thermal and mechanical properties were assessed. The results showed that the mechanical properties of injection-molded samples were not changed significantly either by the washing or by the temperature or screw configuration used in the compounding. Washing reduced the viscosity and molecular mass to a minor extent. As expected, the ash content of the compounded pellets was reduced by washing. The thermo-oxidative stability decreased with increasing compounding temperature and with washing.

Tuning the Morphology of HDPE/PP/PET Ternary Blends by Nanoparticles: A Simple Way to Improve the Performance of Mixed Recycled Plastics

Due to a very low mixing entropy, most of the polymer pairs are immiscible. As a result, mixing polymers of different natures in a typical mechanical recycling process leads to materials with multiple interfaces and scarce interfacial adhesion and, consequently, with unacceptably low mechanical properties. Adding nanoparticles to multiphase polymeric matrices represents a viable route to mitigate this drawback of recycled plastics. Here, we use low amounts of organo-modified clay (Cloisite® 15A) to improve the performance of a ternary blend made of high-density polyethylene (HDPE), polypropylene (PP), and polyethylene terephtalate (PET). Rather than looking for the inherent reinforcing action of the nanofiller, this goal is pursued by using nanoparticles as a clever means to manipulate the micro-scale arrangement of the polymer phases. Starting from theoretical calculations, we obtained a radical change in the blend microstructure upon the addition of only 2-wt.% of nanoclay, with the obtaining of a finer morphology with an intimate interpenetration of the polymeric phases. Rather than on flexural and impact properties, this microstructure, deliberately promoted by nanoparticles, led to a substantial increase (>50 °C) of a softening temperature conventionally defined from dynamic-mechanical measurements.

Characterization of tars from recycling of PHA bioplastic and synthetic plastics using fast pyrolysis

The aim of this study was to investigate the pyrolysis products of polyhydroxyalkanoates (PHAs), polyethylene terephthalate (PET), carbon fiber reinforced composite (CFRC), and block co-polymers (PS-b-P2VP and PS-b-P4VP). The studied PHA samples were produced at temperatures of 15 and 50 ^oC (PHA15 and PHA50), and commercially obtained from GlasPort Bio (PHAc). Initially, PHA samples were analyzed by nuclear magnetic resonance (NMR) spectroscopy and size exclusion chromatography (SEC) to determine the molecular weight, and structure of the polymers. Thermal techniques such as thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses were performed for PHA, CFRC, and block co-polymers to investigate the degradation temperature range and thermal stability of samples. Fast pyrolysis (500 ^oC, ∼10² °C s^-1) experiments were conducted for all samples in a wire mesh reactor to investigate tar products and char yields. The tar compositions were investigated by gas chromatography-mass spectrometry (GC-MS), and statistical modeling was performed. The char yields of block co-polymers and PHA samples (<2 wt. %) were unequivocally less than that of the PET sample (~10.7 wt. %). All PHA compounds contained a large fraction of ethyl cyclopropane carboxylate (~ 38-58 %), whereas PAH15 and PHA50 additionally showed a large quantity of 2-butenoic acid (~8-12 %). The PHAc sample indicated the presence of considerably high amount of methyl ester (~15 %), butyl citrate (~12.9 %), and tributyl ester (~17 %). The compositional analyses of the liquid fraction of the PET and block co-polymers have shown carcinogenic and toxic properties. Pyrolysis removed matrices in the CRFC composites which is an indication of potential recovery of the original fibers.

Chemical recycling: A critical assessment of potential process approaches

Increased media coverage of plastic pollution in the environment and import bans on plastic waste in several countries have resulted in plastic waste becoming one of the most discussed waste streams in recent years. In the European Union (EU), only about one-third of the post-consumer plastic waste is recycled; the rest goes to energy recovery and landfilling in equal parts. In connection to the necessary increase in efforts to achieve the ambitious EU recycling targets, chemical recycling is currently receiving more and more attention. The assumption is that chemical recycling processes could open up new waste streams for recycling and generate valuable raw materials for the chemical industry. Although there exists no legal definition for chemical recycling, there is more or less agreement that it covers the conversion of plastic polymers into their monomers or chemical building blocks. Techniques such as gasification, pyrolysis and liquefaction as well as solvolysis can be used for chemical recycling. So far, only few large-scale plants for chemical recycling exist worldwide. This article presents the different processes by means of examples from (formerly) running installations and their suitability for plastics recycling is assessed. However, to date, only few chemical recycling plants are in continuous operation, and further scientific evidence for the ecological and economic benefits is still necessary for final evaluation.

Ignored microplastic sources from plastic bottle recycling

The recovery and recycling of plastic products has increased dramatically in recent years as a strategy to achieve sustainable production and minimization of plastic pollution. However, the release of microplastics during plastic recycling has received little attention. We evaluated the generation and fate of microplastics in three typical facilities which make polyethylene terephthalate (PET) flakes using post-consumer PET bottles as raw material. Microplastics, 0.1- 5.0 mm in size, were detected in production wastewater at concentrations ranging from 23.43 ± 1.04 mg/L to 1836.37 ± 31.73 mg/L, while decreased to (8.13 ± 0.42-83.83 ± 0.93) mg/L in discharge effluent and (52,166 ± 2858-68,866 ± 2500) μg/g in sludge. Interestingly, the profiles of microplastics in samples from production wastewater, effluents, and sludge showed significant differences. Although, in all three compartments, the mass of microplastics increased, and the particle number decreased with increasing particle size. Overall, the removal ratio of total microplastics from the production wastewater was 53.47 ± 4.48% to 99.56 ± 0.02% in mass, and from 90.08 ± 0.82% to 99.56 ± 0.05% in quantity. The loss of microplastics from wastewater resulted in their concentration in sludge. Factors that influence the transfer of microplastics from wastewater to sludge should be identified and utilized to maintain a high level of removal and prevent leakage of these particles into the environment.

Non-permanent primary food packaging materials assessment: Identification, migration, toxicity, and consumption of substances

Almost all processed food comes packaged in either plastic, glass, metal, or paper and paperboard materials, and many packaging materials are disposed of after a single use (linear economy). Based on the concept of a circular economy, the recycling of food packaging materials has become one of the main targets for industries and regulators around the world. However, recycling presents particular challenges, mainly related to the recycled material composition, which determines its reusability, application, functionality, and chemical safety. In this latter matter, it has been demonstrated that the use of recycled food packaging materials increases the number and possible sources of substances that could be present in the packaging material, which is of concern as substances that can migrate into food and cause health hazards upon consumption. This review compiles information regarding substances detected in non-permanent food packaging materials, focusing mainly on plastics, paper, and paperboards. The compilation of literature studies (110 research articles) on the presence of intentionally added substances (IAS) and non-intentionally added substances (NIAS) in food packaging materials, their migration, toxicity, and dietary exposure has been summarized, evaluated, and discussed. In addition, current sustainable food packaging trends have been mentioned. Finally, approaches to reduce the presence, migration, and potential exposure to substances that have migrated from packaging materials into food have been reviewed.

Sampling Scheme Conception for Pretreated Polyolefin Waste Based on a Review of the Available Standard Procedures

Given the rapid development of plastics recycling in recent years, the need for guidelines for sampling and material characterization is steadily emerging. However, there still exists a considerable scarcity of methods that enable proper material data acquisition. This paper consists of two parts. The first part provides a critical review of the available sampling techniques that can be utilized in the field of plastics recycling. Several sampling studies were covered in the review alongside the prominent standardization institutions. It was found that neither the literature nor the standards provide a comprehensive practice that considers the distinctive characteristics of plastic waste and applies it to different situations along the value chain. In the second part, a proposal of a sampling plan for pretreated rigid plastic waste is conceptualized based on selected information from the reviewed methods. Two variants of the proposed plan were evaluated based on the flake size distribution and the apparent density of four different pretreated polyolefin (PO) waste materials. The results of the study showed that combining stratified random sampling with composite sampling yields a good sampling technique for rigid PO waste. Moreover, the analysis of a composite sample adequately conveys the true material properties of a sublot or lot.

“I don’t think education is the answer”: a corpus-assisted ecolinguistic analysis of plastics discourses in the UK

Ecosystems around the world are becoming engulfed in single-use plastics, the majority of which come from plastic packaging. Reusable plastic packaging systems have been proposed in response to this plastic waste crisis, but uptake of such systems in the UK is still very low. This article draws on a thematic corpus of 5.6 million words of UK English around plastics, packaging, reuse, and recycling to examine consumer attitudes towards plastic (re)use. Utilizing methods and insights from ecolinguistics, corpus linguistics, and cognitive linguistics, this article assesses to what degree consumer language differs from that of public-facing bodies such as supermarkets and government entities. A predefined ecosophy, prioritizing protection, rights, systems thinking, and fairness, is used to not only critically evaluate narratives in plastics discourse but also to recommend strategies for more effective and ecologically beneficial communications around plastics and reuse. This article recommends the adoption of ecosophy in multidisciplinary project teams, and argues that ecosophies are conducive to transparent and reproducible discourse analysis. The analysis also suggests that in order to make meaningful change in packaging reuse behaviors, it is highly likely that deeply ingrained cultural stories around power, rights, and responsibilities will need to be directly challenged.

Biobased plastic: A plausible solution toward carbon neutrality in plastic industry?

Biobased plastic exhibits unique benefits for achieving carbon neutrality, a key step toward reducing atmospheric greenhouse gases, due to its stability, high carbon content, and origin of carbon by photosynthesis. Herein we evaluate the role and potential of biobased plastic as an alternative carbon reservoir which is completely artificial, since most plastic polymers are synthetic and massively produced after the 1950 s. Model simulation indicates that plastic, under usage, burial, and littering, forms a growing carbon reservoir, sinking 6.82 gigatons of carbon (GtC) in 2020. Plastic-formed carbon is estimated to stack up to 19.4-23.2 GtC in 2060 under various production scenarios. However, only 18-40% of carbon stored in plastic is biobased carbon, equivalent to approximately 31-48 gigatons of carbon dioxide. Without any low carbon energy upgrade, carbon neutrality is difficult to achieve even with 90% biobased plastic substitution and 50% recycling ratio. Because extra GHG emissions are generated as a result of increasingly using incineration as a post-treatment strategy in response to increasing waste generation, the annual net GHG emission continues to rebound after the bio-based plastic substitution and plastic recycling approach their upper limits. Additional strategies are therefore needed to achieve complete carbon neutrality.

Roadmap to sustainable plastic waste management: a focused study on recycling PET for triboelectric nanogenerator production in Singapore and India

This study explores the implications of plastic waste and recycling management on recyclates for manufacturing clean-energy harvesting devices. The focus is on a comparative analysis of using recycled polyethylene terephthalate (PET) for triboelectric nanogenerator (TENG) production, in two densely populated Asian countries of large economies, namely Singapore and India. Of the total 930,000 tonnes of plastic waste generated in Singapore in 2019, only 4% were recycled and the rest were incinerated. In comparison, India yielded 8.6 million tonnes of plastic waste and 70% were recycled. Both countries have strict recycling goals and have instituted different waste and recycling management regulations. The findings show that the waste policies and legislations, responsibilities and heterogeneity in collection systems and infrastructure of the respective country are the pivotal attributes to successful recycling. Challenges to recycle plastic include segregation, adulterants and macromolecular structure degradation which could influence the recyclate properties and pose challenges for manufacturing products. A model was developed to evaluate the economic value and mechanical potential of PET recyclate. The model predicted a 30% loss of material performance and a 65% loss of economic value after the first recycling cycle. The economic value depreciates to zero with decreasing mechanical performance of plastic after multiple recycling cycles. For understanding how TENG technology could be incorporated into the circular economy, a model has estimated about 20 million and 7300 billion pieces of aerogel mats can be manufactured from the PET bottles disposed in Singapore and India, respectively which were sufficient to produce small-scale TENG devices for all peoples in both countries.

Improving the Material and Financial Circularity of the Plastic Packaging Value Chain in The Netherlands: Challenges, Opportunities, and Implications

This article outlines a bespoke process for uncovering crucial economic and social considerations in the quest to convert the Dutch plastic packaging system from a linear to a circular economy. Using a serious game tool as part of a qualitative research method, we developed, prioritized, and elaborated on various conceivable and effective policies that would create a circular plastic packaging value chain in The Netherlands. A key aim of this study was to fill a gap in the predominantly technical-focused research in this area by offering a holistic overview of how a circular economy impacts key industry stakeholders and their business models, as well as highlight system-level consequences of these policies, were they to be adopted. We used simulation and statistical analyses to explore the effects of these policies on the material and financial circularity of the Dutch plastic packaging value chain. The results reflect that one of the policies—establishing a center of excellence —would benefit the Dutch plastic packaging system the most.

Quality of recycling: Urgent and undefined

Quality of recycling is a concept used by many authors in the scientific literature and the EU legislator. However, a clear definition of what is intended for quality of recycling and a framework for operationalising it is lacking. Most studies, while proposing indicators reflecting quality, leave the concept of quality largely undefined. Such lack of clarity is an obstacle to the conception of robust policies addressing recycling and circular economy. In this article, we review the available studies investigating on recycling quality, synthetize the approaches available and conclude suggesting a way forward for research to operationalise the definition to support circular economy policy measures and monitoring. Essentially, quality is not an on/off criterion. The definition of quality of recycling should consider that quality depends on technical characteristics of the recyclate, which determine if it is adequate (thus functional) for a certain end application or not. Furthermore, it should consider that the recyclate can be used in different end applications over different markets and that can be adequate for substitution of primary resources in certain applications, but less or not in others. At system-wide level, this results in a certain degree of virgin resource substitution. To this end, preserving functionality, i.e. minimising the recyclate loss of functions via functional recycling, is key. Drawing upon studies on waste management, life cycle assessment and resource dissipation, we link the concept of functionality to substitutability of virgin resources and broader suitability in the circular economy, striving to show the linkages between different perspectives.

Raman technology application for plastic waste management aligned with FAIR principle to support the forthcoming plastic and environment initiatives

Plastic production and worldwide use of plastic materials have continued to rise due to their convenience and excellent marketing advantages. This is generating an environmental crisis and global scale pollution which is one of the greatest threats to our planet. One of the best responses could be accomplished by improving recycling and waste management strategies. In this paper we conducted Raman analyses of representative stock of plastics aged in terrestrial or aquatic environments spanning in age up to 15 years. We aimed to establish any potential influence of the aging conditions on the Raman signature of specific plastics. This information is further used to build up a Raman logic gate for automatic sorting of plastic waste recovered from environment. Pigments and aging introduced indeed small changes in the Raman signature of the respective plastics. However, we were able to identify unique spectral ranges characteristic for the main plastic types and intensity threshold of fingerprint bands sufficiently strong for building robust Raman barcodes for sorting. Waste plastics Raman data handling and the proposed methodology for sorting complies with the FAIR (Findability, Accessibility, Interoperability and Reusability) principles of scientific data, being useful for researchers, policymakers and stakeholders. Our spectral characterization of solid plastic waste comes in support of improved waste plastic management and could have economic and environmental positive impact.

Durability Enhancement of Sustainable Concrete Composites Comprising Waste Metalized Film Food Packaging Fibers and Palm Oil Fuel Ash

The utilization of waste materials in sustainable and green concrete manufacturing is particularly appealing because of the low cost of waste resources, the saving of landfill space, and the development and enhancement of concrete qualities. This paper investigates the strength and durability of green concrete composites made of waste metalized film food packaging (MFP) fibers and palm oil fuel ash (POFA). Compressive and tensile strengths, carbonation, drying shrinkage, electrical resistivity, and rapid chloride penetration tests in concrete mixtures are among the properties explored. With ordinary Portland cement (OPC), MFP fibers of 20 mm in length and six-volume fractions ranging from 0 to 1.25% were employed. Another six concrete mixes were made with 20% POFA in place of OPC. The results showed that adding MFP fibers to concrete mixes reduced their compressive strength. Despite a minor reduction in compressive strength, the inclusion of MFP fibers significantly increased tensile strength. The findings show that the combination of MFP fibers with POFA substantially impacts concrete durability. The addition of MFP fibers to concrete mixes resulted in a reduction in carbonation and drying shrinkage. The chloride penetration of specimens was also reduced, whereas the electrical resistivity of reinforced samples rose by nearly 80% compared to ordinary concrete.

Studying Waste Separation Behaviors and Environmental Impacts toward Sustainable Solid Waste Management: A Case Study of Bang Chalong Housing, Samut Prakan, Thailand

This study aims to develop more inclusive and sustainable waste management practices to be implemented in Bang Chalong Housing, a model community with unsatisfactory waste separation and recycling rate. The extended theory of planned behavior was employed to investigate the effect of attitude, subjective norm, perceived behavioral control, knowledge, and situational factors on household waste separation intention and behavior, using structural equation modeling as a tool. Based on the questionnaire responses of 321 residents, the house owner’s status exhibited a considerable impact on waste-sorting behavior. Knowledge (β = 0.653; p < 0.001) and subjective norm (β = 0.160; p < 0.05) were two significant predictors of the respondents’ intention, which showed a strong influence on household waste separation behavior (β = 0.804; p < 0.001). Various waste management scenarios were also evaluated through material flow analysis and life cycle assessment. Installing a waste-sorting plant in addition to the current approach (recycling and landfilling) could annually reduce 26.4 tons of solid waste from being landfilled and mitigate GHG emissions by up to 47.4 tons CO2 equivalent. Finally, the implications of these results on designing interventions and amending waste management schemes were discussed.

Increasing the Circularity of Packaging along Pharmaceuticals Value Chain

Pharmaceutical packaging is a complex group of products, the main purpose of which is to protect the medicine and forward information. Pharmaceutical packaging waste is generated and accumulated along the various phases and practices of the value chain. In general, the amount of packaging has been growing during the increasing political pressure to reduce waste and to increase the circulation of materials. The goals and solutions are expected to be found in the circular economy; however, the literature on circular pharmaceutical packaging is lacking. This study explores the key factors when promoting the circularity of pharmaceutical packaging along its value chain. This was conducted by reviewing the legislation, elaborating the value chain and analysing the data from focus group discussions with stakeholders. The results show that various barriers, such as legislation, a lack of information or interaction between stakeholders, but also rigid practices, block product design for circularity. In the developing circularity of packaging, the causal links along the value chain must be understood. Chemical recycling technologies are expected to resolve the challenges of maintaining clean cycles. Further studies are needed to demonstrate the environmental benefits of increasing circularity along the value chain of pharmaceutical packaging.

Toward Microbial Recycling and Upcycling of Plastics: Prospects and Challenges

Annually, 400 Mt of plastics are produced of which roughly 40% is discarded within a year. Current plastic waste management approaches focus on applying physical, thermal, and chemical treatments of plastic polymers. However, these methods have severe limitations leading to the loss of valuable materials and resources. Another major drawback is the rapid accumulation of plastics into the environment causing one of the biggest environmental threats of the twenty-first century. Therefore, to complement current plastic management approaches novel routes toward plastic degradation and upcycling need to be developed. Enzymatic degradation and conversion of plastics present a promising approach toward sustainable recycling of plastics and plastics building blocks. However, the quest for novel enzymes that efficiently operate in cost-effective, large-scale plastics degradation poses many challenges. To date, a wide range of experimental set-ups has been reported, in many cases lacking a detailed investigation of microbial species exhibiting plastics degrading properties as well as of their corresponding plastics degrading enzymes. The apparent lack of consistent approaches compromises the necessary discovery of a wide range of novel enzymes. In this review, we discuss prospects and possibilities for efficient enzymatic degradation, recycling, and upcycling of plastics, in correlation with their wide diversity and broad utilization. Current methods for the identification and optimization of plastics degrading enzymes are compared and discussed. We present a framework for a standardized workflow, allowing transparent discovery and optimization of novel enzymes for efficient and sustainable plastics degradation in the future.

A review of the plastic value chain from a circular economy perspective

Although plastic is one of the most commonly used materials in our everyday life, the current linear economy ('produce, use and dispose') engenders high risks to human health in relation to greenhouse gas (GHG) emissions and environmental pollution. As a response to these challenges, the circular plastic economy is gaining momentum, where the goal is to reduce, reuse and recycle all plastic. The transition to the circular economy should be made across the entire plastics value chain in order to ensure circular design, production, use and waste management. This study examines the current scientific literature in relation to the entire value chain of plastics. This aim of the article is to provide an overview of the existing research (and highlight research gaps) associated with the transition of plastic use to a circular model. The literature was divided into the following categories: 1) design; 2) production; 3) use; 4) end-of-life; and 5) value chain. A high proportion of the literature was found to address the end-of-life phase, suggesting that the other phases are currently neglected. The results have implications that are applicable to multiple phases; in particular, contamination of waste streams and composite materials places significant limitations on the opportunity to recycle and reuse plastic in new products. This calls for changes in the whole value chain, and for trans-sectorial collaboration to ensure systemic transparency. Therefore, future research should take a holistic approach to the transition to circular through careful mapping of implications, stakeholder involvement and collaboration.

The Health and Environmental Impact of Plastic Waste Disposal in South African Townships: A Review

Twenty-first century human behaviour continues to escalate activities that result in environmental damage. This calls for environmentally friendly solutions, such as waste recycling and handling, to deal with the increased amount of waste, especially plastics. The plastic materials manufacturing sector is booming, particularly packaging; while only a fraction of its waste is recycled, another fraction is destroyed, and the larger part continues to pollute the environment. In addition to other waste disposal activities, destroying plastic or incineration (which could be for energy recovery) is usually subjected to strict legal requirements because of its effect on the environment. However plastic is destroyed or disposed of, it poses a serious challenge in both the short term and the long term to humans and their natural environment if the process is not efficiently managed. This article describes how a growing amount of plastic waste is disposed of haphazardly in South African townships, while most of the inhabitants are not aware or do not care about the adverse environmental and health effects of these actions. This article examines the environmental and health effects of poor plastic disposal in South African townships as it is in other developing countries to sensitise the citizens to the significance of reducing plastic waste quantities, which will downplay their impact on human health and the environment.

Technical and environmental assessment of laboratory scale approach for sustainable management of marine plastic litter

Laboratory scale recycling of marine plastic litter consisting of polyethylene terephthalate (PET) bottle sorting, pyrolysis and chemical vapor deposition (CVD) was conducted to identify the technical and environmental implications of the technology when dealing with real waste streams. Collected seashore and underwater plastics (SP and UP, respectively) contained large quantities of PET bottles (33.2 wt% and 61.4 wt%, respectively), suggesting PET separation was necessary prior to pyrolysis. After PET sorting, marine litter was converted into pyrolysis oil and multi-walled carbon nanotubes (MWCNTs). Water-based washing of litter prior to pyrolysis did not significantly change the composition of pyrolysis products and could be avoided, eliminating freshwater consumption. However, distinct differences in oil and MWCNT properties were ascribed to the variations in feedstock composition. Maintaining consistent product quality would be one of challenges for thermochemical treatment of marine litter. As for the environmental implications, life cycle assessment (LCA) demonstrated positive benefits, including improved climate change and fossil depletion potentials. The highest positive environmental impacts were associated with MWCNT production followed by pyrolysis oil and PET recovery. The benefits of proposed approach combining PET sorting, pyrolysis and CVD allowed to close the waste loop by converting most of the marine litter into valuable products.

Recycling of dielectric electroactive materials enabled through thermoplastic PDMS

In the green transition, actuators and generators play an essential role in the development of sustainable solutions across a broad range of applications. In this context, dielectric transducers are advocated as one of the most promising solutions in terms of effectiveness, lifetime and running costs. However, they are classically produced as sandwich structures, whereby a cross-linked dielectric material is placed between two compliant electrodes. From a materials consumption viewpoint, this is problematic, since it will inherently result in a loss of material during production as well as inhibit the recycling of expended systems when their life comes to an end. Herein, we present a cleaning method employing surfactants and sonication to remove electrodes from the surface of the dielectric material. By applying a thermoplastic silicone elastomer as the dielectric material, it is possible to reprocess the material by hot-pressing, and to prepare new actuators after the rinsing process. This effectively shows that recycling production scrap, for example, is possible. By comparing the cleaned material with a directly recycled material, it is clear that cleaning removes a critical amount of metals from the material and enables recycling for at least five cycles. Comparatively, a directly recycled material is prone to a high leakage current and premature electronic breakdown after only two cycles. This simple cleaning process, in combination with use of a thermoplastic dielectric material, enables less waste from production as well as the possibility of reclaiming and recycling materials in general.

A new recycling method for silver-coated DEAs produced from thermoplastic elastomers. Recycled DEAs retain their dielectric and mechanical properties in five recycling loops in contrast to direct recycling that only permitted a single recycling loop.

Conversion of Plastic Waste into Supports for Nanostructured Heterogeneous Catalysts: Application in Environmental Remediation

Plastics are ubiquitous in our society and are used in many industries, such as packaging, electronics, the automotive industry, and medical and health sectors, and plastic waste is among the types of waste of higher environmental concern. The increase in the amount of plastic waste produced daily has increased environmental problems, such as pollution by micro-plastics, contamination of the food chain, biodiversity degradation and economic losses. The selective and efficient conversion of plastic waste for applications in environmental remediation, such as by obtaining composites, is a strategy of the scientific community for the recovery of plastic waste. The development of polymeric supports for efficient, sustainable, and low-cost heterogeneous catalysts for the treatment of organic/inorganic contaminants is highly desirable yet still a great challenge; this will be the main focus of this work. Common commercial polymers, like polystyrene, polypropylene, polyethylene therephthalate, polyethylene and polyvinyl chloride, are addressed herein, as are their main physicochemical properties, such as molecular mass, degree of crystallinity and others. Additionally, we discuss the environmental and health risks of plastic debris and the main recycling technologies as well as their issues and environmental impact. The use of nanomaterials raises concerns about toxicity and reinforces the need to apply supports; this means that the recycling of plastics in this way may tackle two issues. Finally, we dissert about the advances in turning plastic waste into support for nanocatalysts for environmental remediation, mainly metal and metal oxide nanoparticles.

Entrained Flow Gasification of Polypropylene Pyrolysis Oil

Petrochemical products could be produced from circular feedstock, such as waste plastics. Most plants that utilize syngas in their production are today equipped with entrained flow gasifiers, as this type of gasifier generates the highest syngas quality. However, feeding of circular feedstocks to an entrained flow gasifier can be problematic. Therefore, in this work, a two-step process was studied, in which polypropylene was pre-treated by pyrolysis to produce a liquid intermediate that was easily fed to the gasifier. The products from both pyrolysis and gasification were thoroughly characterized. Moreover, the product yields from the individual steps, as well as from the entire process chain, are reported. It was estimated that the yields of CO and H₂ from the two-step process were at least 0.95 and 0.06 kg per kg of polypropylene, respectively, assuming that the pyrolysis liquid and wax can be combined as feedstock to an entrained flow gasifier. On an energy basis, the energy content of CO and H₂ in the produced syngas corresponded to approximately 40% of the energy content of the polypropylene raw material. This is, however, expected to be significantly improved on a larger scale where losses are proportionally smaller.

Towards Higher Quality of Recycled Plastics: Limitations from the Material’s Perspective

The increasing consumption of plastics and plastic products results in correspondingly substantial volumes of waste, which poses considerable environmental burdens. With the ongoing environmental actions, the application of circular economy on this waste stream is becoming inevitable. In this paper, the topics of plastics recycling, circular economy on plastics, and challenges to plastic waste recycling are critically reviewed. In the first part of this paper, the development of research on plastic recycling was viewed from 1950 until 2020 using the scientific database Web of Science, and 682 related studies were found and used to assess the changing research priorities along that timeline. The following sections discuss the potentials and requirements to enhance the quality of the produced recycled plastic, in connection with the factors that currently limit it. In conclusion, the quality of recycled plastic is generally determined by the homogeneity of the recovered plastic feed. There are various strategies which could be implemented to overcome the hindrances identified in the paper and to improve the quality of the recycled plastic, such as working on enhanced product designs for minimised waste heterogeneity and controlling the materials’ degree of contamination by applying advanced sorting.

Polyolefins and Polyethylene Terephthalate Package Wastes: Recycling and Use in Composites

Plastics are versatile materials used in a variety of sectors that have seen a rapid increase in their global production. Millions of tonnes of plastic wastes are generated each year, which puts pressure on plastic waste management methods to prevent their accumulation within the environment. Recycling is an attractive disposal method and aids the initiative of a circular plastic economy, but recycling still has challenges to overcome. This review starts with an overview of the current European recycling strategies for solid plastic waste and the challenges faced. Emphasis lies on the recycling of polyolefins (POs) and polyethylene terephthalate (PET) which are found in plastic packaging, as packaging contributes a signification proportion to solid plastic wastes. Both sections, the recycling of POs and PET, discuss the sources of wastes, chemical and mechanical recycling, effects of recycling on the material properties, strategies to improve the performance of recycled POs and PET, and finally the applications of recycled POs and PET. The review concludes with a discussion of the future potential and opportunities of recycled POs and PET.