Waste Electrical And Electronic Equipment Plastics Research Articles

Environmental benefit of recycling plastics from waste electrical & electronic equipment

Plastic recycling from waste electrical and electronic equipment (WEEE) can effectively deal with both the resource crisis and environmental pollution. However, the life cycle environmental impacts of recycling plastics derived from WEEE are still unclear. Therefore, this study adopts life cycle assessment and machine learning methods to estimate the environmental impacts and mitigation potentials of WEEE plastics recycling. We find the environmental degradation of WEEE waste plastics recycling are mainly from electricity consumption and transportation during the disassembly and granulation stages. Significant variation in the reduction effect of WEEE plastics recycling technologies is observed, ranging from 13 % to 77 %. The WEEE generation is projected to exhibit an S-shaped trend from 103 tonnes in 1980 to 15.42 million tonnes (Mt) in 2050, contributing to 10.33 Mt of carbon reduction. Improving the efficiency of WEEE plastics recycling technologies and enhancing legal recycling of waste air conditioner can efficiently reduce environmental emissions.

Influence of Feedstock Particle Size on the Certain Determination of Chlorine and Bromine in Pyrolysis Oils from Waste Electrical and Electronic Equipment Plastics.

Rejected streams emerging from waste sorting and recycling plants are still capable of being valorized by unconventional recycling routes. This is the case of the plastic-rich fraction generated after the treatment of waste electrical and electronic equipment (WEEE). However, the material complexity of this stream supposes a handicap when it comes to obtaining repetitive results in laboratory-scale recycling processes. This work aims to highlight the influence that the pretreatment (mainly particle size reduction) of a real WEEE plastic-rich stream has on the variability of the concentration of halogens (representative pollutants) in the oils obtained from its recycling via pyrolysis. The pretreatment steps were based on the standards of the European Committee for Standardization (ECN) for the analysis of waste samples. Four samples were studied: the WEEE plastics as received; two milled samples (2 and 1 mm particle size) derived from the original one; and a simulated sample composed of virgin polymers. All the samples were treated under the same conditions: 500 °C reaction temperature, 15 °C min-1 heating rate, 30 min dwell time, and a 1 L min-1 nitrogen purge flow. The oils obtained in, at least, two pyrolysis tests performed on the same sample were deeply characterized, and the results were compared. The oils derived from the "as-received" sample showed an unacceptable relative standard deviation (RSD, ∼42%) in the chlorine concentration. The sample milled to 2 mm reduced the RSD on the concentration of chlorine in the oils down to 8%, while no enhancement in the results was observed for the further milled sample. The other two major pyrolysis fractions were also characterized, showing an overall enhancement in the RSD of the analysis of the main components of the gases, while no improvement in the solids pollutants' characterization was achieved.

Enhancement of recycling system for large WEEE plastics in Korea via material flow analysis (MFA) and hazardous substances assessment

Globally, there is interest in recycling waste electrical and electronic equipment (WEEE) plastics for transition to circular resource society and concern about substances with potential harzard in WEEE. For high-quality recycling of WEEE plastics, it is necessary to find factors that hinder recycling of the entire life of plastics and investigate hazardous substances for recycling safety. In this study, through conducting material flow analysis(MFA), 27 kt of WEEE was collected and only 3.9 % of the production was returned to plastic recycling market. To resolve this gap, further research by related organizations, including updating statistical data on the plastics, is required in addition to consideration for converting unofficial routes into official routes. For the activation of the secondary material recycling market, strict quality control is required, because some samples contained relatively high levels of PBDEs DEHP restricted under law. And it is necessary to monitor of unrestricted substance, TBBPA and Bisphenol A detected at high concentration in WEEE plastic, for the safe recycling of plastic waste.

Stepwise flotation separation of WEEE plastics by polymeric aluminum chloride towards source control of microplastics

The mismanagement of waste electrical and electronic equipment (WEEE) resulted in numerous discarded plastics in the natural environment, and these waste plastics might experience aging, breaking, and migration, which becomes a crucial microplastic source. Sustainable management of WEEE plastics presents a considerable opportunity for resource recovery and microplastic pollution prevention. Flotation separation is a significant process of mechanical recycling, while most flotation methods can only deal with binary plastic mixtures. In this work, an advanced, stepwise, and sustainable flotation method was advocated to separate multi-plastics by polymeric aluminum chloride (PAC) modification. The abundant hydrophilic groups and environmental friendliness of PAC prompted us to further investigate the wetting effect. PAC had varied hydrophilization effects on acrylonitrile butadiene styrene (ABS) and polystyrene (PS) surfaces, but polyethylene terephthalate (PET) retained hydrophobicity. Treatment conditions, including PAC dosage, temperature, time, and pH were optimized. 100% of PET could be purified after primary separation, and the purities of ABS and PS could reach 100% and 97.4% after secondary separation, respectively. The strength of the interaction was determined by the different surface potentials and functional groups. In PAC solution, long-chain molecules or ions might interact with plastic surfaces electrostatically, and Al3+ could bridge long-chain molecules and plastic surfaces, thereby strengthening the polymer hydrophilicity. We further improved the PAC treatment process, and the reuse of PAC reduced modifier usage to 84.4 g/ton waste plastics, which was cost-effective in industrial applications. A preliminary evaluation of the energy consumption and environmental impact indicated that PAC treatment was superior to other modification methods. This work is an initial attempt at the stepwise separation of waste plastic and shows promising prospects for recycling plastic waste.

Assessment of critical factors in waste electrical and electronic equipment (WEEE) plastics on the recyclability: A case study in Finland

Excessive waste is continually accumulating owing to increased consumption, and an excellent example is the consumption of electrical and electronic equipment (EEE), which are eventually transformed into waste from electrical and electronic equipment (WEEE). WEEE is an interesting material stream because it includes various valuable materials that have great potential for recycling and reutilization. To maximize recycling and utilization potential, all fractions in WEEE must be reviewed from a sustainable perspective. Several WEEE contain plastic, which comprises approximately one-third of the total WEEE composition; thus, this plastic content is a good target for recycling purposes. However, the recycling of WEEE plastics might include some challenges, such as the treatment of harmful substances in the material, which can prevent effective and high-quality material recycling. This study investigates the polymer composition and critical elements of the material stream of WEEE polymer. These polymers were identified using portable near-infrared (NIR) spectroscopy and energy-dispersive X-ray spectroscopy (EDS) at an elemental level. The results showed that among various other polymers, acrylonitrile butadiene styrene (ABS) was the main polymer identified in WEEE. The proportion of unidentified polymers was alarmingly large; specifically, when the presence of bromine was positively correlated with the presence of an unidentified WEEE polymer. This study also corroborated that bromine is actually not present in bromine-free plastics, demonstrating that industrial classification works with WEEE polymers.

Recycling Plastics from WEEE: A Review of the Environmental and Human Health Challenges Associated with Brominated Flame Retardants

Waste electrical and electronic equipment (WEEE) presents the dual characteristic of containing both hazardous substances and valuable recoverable materials. Mainly found in WEEE plastics, brominated flame retardants (BFRs) are a component of particular interest. Several actions have been taken worldwide to regulate their use and disposal, however, in countries where no regulation is in place, the recovery of highly valuable materials has promoted the development of informal treatment facilities, with serious consequences for the environment and the health of the workers and communities involved. Hence, in this review we examine a wide spectrum of aspects related to WEEE plastic management. A search of legislation and the literature was made to determine the current legal framework by region/country. Additionally, we focused on identifying the most relevant methods of existing industrial processes for determining BFRs and their challenges. BFR occurrence and substitution by novel BFRs (NBFRs) was reviewed. An emphasis was given to review the health and environmental impacts associated with BFR/NBFR presence in waste, consumer products, and WEEE recycling facilities. Knowledge and research gaps of this topic were highlighted. Finally, the discussion on current trends and proposals to attend to this relevant issue were outlined.

Recycled WEEE plastics in China: Generation trend and environmental impacts

Sustainable management of waste electrical and electronic equipment (WEEE) offers a significant opportunity for resource recovery. However, the generation of plastics in WEEEs and the environmental impacts related to subsequent recycling have not been well addressed. This study estimates the generation volumes of plastics that are recycled from five typical kinds of WEEEs in China and analyzes the environmental performance of WEEE plastics recycling using life cycle assessment (LCA). The results show that recycled plastics from WEEEs increased from 231.6 kt in 2010 to 565.8 kt in 2018, by an average rate of 11.8% per year, with acrylonitrile-butadiene-styrene (ABS), polypropylene (PP) and polystyrene (PS) being the three main components. In 2018, the estimated total electricity consumption and greenhouse gas emissions caused by Chinese WEEE plastics recycling reached 238.6 million kWh and 712.1 kt CO2 eq, primarily due to energy consumption, transportation and WEEE disassembling processes. Based on the results, we find that recycled plastics from WEEEs demonstrate better performance on most environmental aspects except for ozone depletion as compared to the production of virgin plastics. The ongoing ozone-depleting emissions imply an urgent need for additional actions to minimize potential refrigerant leakage in WEEE plastics recycling. This study provides essential information about the existing WEEE plastics recycling practices in China and offers valuable implications to enhance the recycling of plastic materials from WEEEs and achieve sustainable WEEE management.

Feeding preference of insect larvae to waste electrical and electronic equipment plastics

Waste electrical and electronic equipment (WEEE) plastics not only pollute the environment, but are challenging to treat in an environmentally friendly manner. Biodegradation by insect larvae is potentially an eco-friendly method to treat WEEE plastics, but information about the feeding preference of insect larvae to WEEE plastics is lacking. In this study, a total of nine WEEE and pristine plastics were chosen to feed larvae of the following two insect species, i.e. Galleria mellonella and Tenebrio molitor. G. mellonella larvae significantly favor corresponding pristine plastics compared to two types of WEEE plastics, waste rigid polyurethane (RPU) and waste polystyrene (PS). One possible explanation is the increased chlorine or metals in the WEEE plastics measured using X-ray fluorescence spectrometer analysis. Scanning electron microscopy and Fourier transform infrared spectroscopy show that the destruction of physical structures and changes in surface functional groups were found in the two types of WEEE plastics in the larval frass, implying that the larvae partly biodegraded the plastics. Meanwhile, the powdered waste high impact polystyrene plastics (WHIPS) were ingested, but not the lumpy ones, indicating that the consumption by G. mellonella larvae is improved by the WHIPS physical modification. In addition, G. mellonella larvae presented the following decreasing preference for pristine plastics under individual-plastic-fed mode: RPU > phenol–formaldehyde resin > polyethylene (PE) > polypropylene > PS ≈ polyvinyl chloride; this is possibly due to differences in physical properties and chemical structures of the plastics; feeding preference of the larvae under multiple-plastics-fed mode is relatively consistent to that under individual-plastic-fed mode. Interestingly, the consumption by G. mellonella larvae of PE is higher than that of PS, while T. molitor larvae showed the opposite trend, implying that insect larvae have different plastics preference. The findings provide insights into biodegradation of WEEE plastics by insect larvae.

Biodegradation of plastics from waste electrical and electronic equipment by greater wax moth larvae (Galleria mellonella)

Disposal of the increasing amount of the plastics from waste electrical and electronic equipment (WEEE) is of great concern. In this study, biodegradation feasibility of waste rigid polyurethane (WRPU), waste polystyrene (WPS) and waste acrylonitrile-butadiene-styrene (WABS) from WEEE by Galleria mellonella larvae were investigated. The cumulative consumptions of WRPU, WPS and WABS are 35.08%, 13.41% and 4.87% of the total 2 g plastic within 7 d, respectively. TG-MS shows a decrease in the total weight loss and the changes of weight loss stages, implying that thermal stabilities of the three plastics drop. Meanwhile, Mn and Mw of the WPS and WABS decrease after the digestion, suggesting the depolymerization and biodegradation of the plastics. Fluorescence imaging demonstrates that total fluorescence intensity of the WRPU has a considerable decrease from 5.904 × 109 to 5.140 × 109 after digestion by Galleria mellonella larvae for 24 h. High-throughput sequencing reveals that the relative abundance of Enterococcus in the WABS and WPS groups increases and Enterobacter decreases, while WRPU shows the opposite trend. The findings suggest active adaptability of intestinal microbes to WEEE plastics with different properties, indicate the feasibility of Galleria mellonella larvae biodegrading the WEEE plastics, and provide a new potential biological treatment for WEEE plastics.

Design for Circularity Guidelines for the EEE Sector

The increased diversity and complexity of plastics used in modern devices, such as electrical and electronic equipment (EEE), can have negative impacts on their recyclability. Today, the main economic driver for waste electrical and electronic equipment (WEEE) recycling stems from metal recovery. WEEE plastics recycling, on the other hand, still represents a major challenge. Strategies like design ‘for’, but also the much younger concept of design ‘from’ recycling play a key role in closing the material loops within a circular economy. While these strategies are usually analysed separately, this brief report harmonises them in comprehensive Design for Circularity guidelines, established in a multi-stakeholder collaboration with industry leaders from the entire WEEE value chain. The guidelines were developed at the product and part levels. They are divided in five categories: (1) avoidance of hazardous substances; (2) enabling easy access and removal of hazardous or polluting parts; (3) use of recyclable materials; (4) use of material combinations and connections allowing easy liberation; (5) use of recycled materials. These guidelines are the first harmonised set to be released for the EEE industry. They can readily serve decision-makers from different levels, including product designers and manufacturers as well as policymakers.

Chemical Recycling of WEEE Plastics—Production of High Purity Monocyclic Aromatic Chemicals

More than 200 kg real waste electrical and electronic equipment (WEEE) shredder residues from a German dismantling plant were treated at 650 °C in a demonstration scale thermochemical conversion plant. The focus within this work was the generation, purification, and analysis of pyrolysis oil. Subsequent filtration and fractional distillation were combined to yield basic chemicals in high purity. By means of fractional distillation, pure monocyclic aromatic fractions containing benzene, toluene, ethylbenzene, and xylene (BTEX aromatics) as well as styrene and α-methyl styrene were isolated for chemical recycling. Mass balances were determined, and gas chromatography–mass spectrometry (GC-MS) as well as energy dispersive X-ray fluorescence (EDXRF) measurements provided data on the purity and halogen content of each fraction. This work shows that thermochemical conversion and the subsequent refining by fractional distillation is capable of recycling WEEE shredder residues, producing pure BTEX and other monocyclic aromatic fractions. A significant decrease of halogen content (up to 99%) was achieved with the applied methods.

A Review on the Applicability of Life Cycle Assessment to Evaluate the Technical and Environmental Properties of Waste Electrical and Electronic Equipment

Acrylonitrile–butadiene–styrene (ABS) copolymer and high-impact polystyrene (HIPS) are the plastics most commonly found in waste electrical and electronic equipment (WEEE), although properties generally decline with recycling. Technical studies are important in assessing the properties of recycled plastics and obtaining better evidence of their return or not to the same production cycle, through a study of their impacts and life cycle assessment (LCA). This article aimed at a literature search for information that demonstrates the importance of considering the technical property results of LCA studies on WEEE plastics. LCA studies show that recycling WEEE plastics, when compared with virgin raw material, prevents 87% of ABS gas emissions, in addition to reducing energy consumption by up to 90% for ABS and HIPS. However, some technical properties of recycled WEEE polymer material, such as impact strength and ultimate elongation, decline when compared to virgin materials, which may hinder their reinsertion into the same production cycle. These properties can be enhanced by preparing compatible mixtures of ABS and HIPS, or by mixing them with virgin polymers. Recycled ABS (not mixed with another material) can return to the same production cycle when the goal is to preserve the modulus of elasticity. Studies that investigate properties using LCA are scarce. However, they are important in determining the viability of the material returning or not to the same production cycle, which would impact the process and produce different LCA results. Recycled ABS and HIPS polymers from WEEE can return to the same function even if some properties decline, since properties can be improved when the polymers are properly mixed or made compatible, thereby lowering costs and primarily minimizing the negative environmental impacts.

Ecotoxicity of Plastics from Informal Waste Electric and Electronic Treatment and Recycling.

Plastic materials account for about 20% of waste electrical and electronic equipment (WEEE). The recycling of this plastic fraction is a complex issue, heavily conditioned by the content of harmful additives, such as brominated flame retardants. Thus, the management and reprocessing of WEEE plastics pose environmental and human health concerns, mainly in developing countries, where informal recycling and disposal are practiced. The objective of this study was twofold. Firstly, it aimed to investigate some of the available options described in the literature for the re-use of WEEE plastic scraps in construction materials, a promising recycling route in the developing countries. Moreover, it presents an evaluation of the impact of these available end-of-life scenarios on the environment by means of the life cycle assessment (LCA) approach. In order to consider worker health and human and ecological risks, the LCA analysis focuses on ecotoxicity more than on climate change. The LCA evaluation confirmed that the plastic re-use in the construction sector has a lower toxicity impact on the environment and human health than common landfilling and incineration practices. It also shows that the unregulated handling and dismantling activities, as well as the re-use practices, contribute significantly to the impact of WEEE plastic treatments.

Microwave treatment combined with wetting agent for an efficient flotation separation of acrylonitrile butadiene styrene (ABS) from plastic mixtures

Acrylonitrile butadiene styrene (ABS), as a main component of plastics of waste electrical and electronic equipment (WEEE), shows high potential for recycling, which is restricted by the absence of an efficient separation method. Herein, a novel surface treatment method, microwave treatment combined with a wetting agent, was proposed to selectively change the hydrophilicity of the mixed waste plastics, which efficiently separated ABS from the WEEE plastics by flotation. The results of this approach provided the following optimal conditions, i.e., microwave power 700 W, microwave irradiation time 3 min, concentration of wetting agent carboxymethylcellulose sodium (CMC) 25 mg/L, treatment time with CMC 5 min, stirring rate 1800 rpm, frother concentration 40 mg/L, and flotation time 4 min. Under these optimal conditions, the recovery and the purity of ABS reached 97.70% and 99.86%, respectively. The mechanism of the surface treatment was examined by means of contact angle, Fourier transform infrared spectroscopy (FT-IR), and adsorption kinetics. The results showed that the selective wetting mechanism can be attributed to the physisorption of CMC on the surface of plastics. In conclusion, this surface treatment method is expected to provide technological insights for the separation and recovery of waste ABS from WEEE plastics.

Preparing WEEE plastics for recycling – How optimal particle sizes in pre-processing can improve the separation efficiency of high quality plastics

The production of electrical and electronic equipment is a fast-growing industrial sector, which also results in growing generation of waste electrical and electronic equipment (WEEE). An efficient separation is a prerequisite in order to achieve a high recyclability of WEEE plastics and produce pure types of plastics. The scope of the paper is to investigate the influence of particle size on the recyclability of post-shredding plastic fractions from WEEE pre-processing. For this purpose, different shredding technologies for WEEE, their output particle size, the sorting technologies and their required input particle size were investigated and compared. Sample analysis of plastic flakes provided from pre-processors is performed. The results show that the different sorting technologies require different particle size ranges for efficient separation. Three scenarios were investigated in order to identify optimal output particle sizes for improved plastic recycling. The results suggest that a particle size between 10–20 mm increases the sorting efficiency and thus recyclability of the plastic fractions and minimizes the losses into fines. Further recommendations to pre-processors and recyclers include improving the communication between the end-of-life actors, to standardize the particle size range (10–20 mm) as well as not to dispose the fine fraction but to find recyclers operating appropriate fines sorting technologies.

Auto-sorting commonly recovered plastics from waste household appliances and electronics using near-infrared spectroscopy

Abstract The recycling of plastics from Waste electrical and electronic equipment (WEEE) was constrained by the mix of types. Near-infrared (NIR) spectroscopy is suitable for polymer detection, and it is a rapid, non-destructive analysis method that can be applied to automatic on-line sorting system. The NIR spectra of four commonly recovered WEEE plastics, which are polypropylene (PP), polystyrene (PS), acrylonitrile butadiene styrene (ABS), and acrylonitrile butadiene styrene/polycarbonate (ABS/PC) blend, was collected. The flame-retardant ABS showed difference from ABS in NIR spectra. Three classification methods, which are spectral angle mapper (SAM), partial least squares discriminant analysis (PLS-DA) and linear discriminant analysis combined with principal component analysis (PCA-LDA), was tested. And the classification models trained on the virgin plastics have been compared with the models trained on the WEEE plastic to evaluate how these methods perform under limited training data. PLS-DA is one of the most widely used classification method in spectral data analysis, but it had unsuccessful prediction when the training set only included virgin plastics. But the overall prediction accuracy over 99% could be achieved by the other two whether the training set was the spectra of virgin plastics or WEEE plastics. In general, NIR spectroscopy has the competency of separating WEEE plastics. Finally, an automatic on-line sorting system was designed specifically for the large plastic segments from household appliances and electronics.

Optimization of Surface Treatment Using Sodium Hypochlorite Facilitates Coseparation of ABS and PC from WEEE Plastics by Flotation.

Waste acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) as dominant components in waste electrical and electronic equipment (WEEE) plastics show significant potential for recycling, which is severely restricted by efficient separation method. We proposed a novel surface treatment method using sodium hypochlorite for facilitating coseparation of ABS and PC from WEEE plastics by flotation for recycling. Optimization of surface treatment process was performed with response surface methodology using Box-Behnken design. A quadratic model was generated for predicting the floating rate of ABS and PC, and it was also used to optimize the coseparation performance. The optimum conditions were determined and included concentration of 0.05 M, temperature of 69.5 °C, contact time of 56.5 min, and stirring rate of 200 rpm. Under optimum conditions, the coseparation of ABS and PC was effectively achieved; the recovery and the purity of ABS and PC reached 97.4% and 100.0%, respectively. The formation of oxygen-bearing groups and morphological changes were confirmed as major mechanism to induce the surface hydrophilization of ABS and PC. Consequently, this method is feasible for selective coseparation of ABS and PC from WEEE plastics, and it provides technological insights in the sustainable deposal of WEEE plastics.

Pyrolysis of WEEE plastics using catalysts produced from fly ash of coal gasification

Catalytic pyrolysis of thermoplastics extracted from waste electrical and electronic equipment (WEEE) was investigated using various fly ash-derived catalysts. The catalysts were prepared from fly ash by a simple method that basically includes a mechanical treatment followed by an acid or a basic activation. The synthesized catalysts were characterized using various analytical techniques. The results showed that not treated fly ash (FA) is characterized by good crystallinity, which in turn is lowered by mechanical and chemical treatment (fly ash after mechanical and acid activation, FAMA) and suppressed almost entirely down to let fly ash become completely amorphous (fly ash after mechanical and basic activation FAMB). Simultaneously, the surface area resulted increased. Subsequently, FA, FAMB and FAMA were used in the pyrolysis of a WEEE plastic sample at 400°C and their performance were compared with thermal pyrolysis at the same temperature. The catalysts principally improve the light oil yield: from 59 wt.% with thermal pyrolysis to 83 wt.% using FAMB. The formation of styrene in the oil is also increased: from 243 mg/g with thermal pyrolysis to 453 mg/g using FAMB. As a result, FAMB proved to be the best catalyst, thus producing also the lowest and the highest amount of char and gas, respectively. Open image in new window

A study on the environmental aspects of WEEE plastic recycling in a Brazilian company

Purpose The high consumption of electrical and electronic equipment motivated by the rapid technological advances seen over the years has lead to an increase in the generation of waste electrical and electronic equipment (WEEE). Such residues contain various dangerous substances and therefore deserve special attention. To that end, the Brazilian Policy on Solid Waste has provided guidelines on integrated and solid waste management, such as consumer electronics, aiming at their appropriate disposal and treatment through reverse logistics. In this context, the present work focuses on studying the recycling of some WEEE plastics.

Sustainable and Selective Separation of PVC and ABS from a WEEE Plastic Mixture Using Microwave and/or Mild-Heat Treatment with Froth Flotation.

This study reports simple, selective, and sustainable separation of chlorinated plastic (polyvinyl chloride, PVC) and acrylonitrile butadiene styrene (ABS) containing brominated flame retardants (BFRs) from mixed waste electrical and electronic equipment (WEEE) plastics using microwave and/or mild-heat treatment. Microwave treatment after plastic coating with powdered activated carbon (PAC) selectively increased the hydrophilicity of the PVC surface, which facilitated PVC separation (100% recovery and purity) from the WEEE plastic mixture under the optimum flotation conditions. A further mild-heat treatment for 100 s facilitated selective separation with the highest recovery and purity (100%) of PAC-coated ABS containing BFRs from the remaining plastic mixture due to selective formation of a twisted structure with a lower density than water and the untreated ABS. Mild-heat treatment only of PAC-coated WEEE plastic mixture resulted in successful recovery of (100%) the ABS and PVC. However, the recovered PVC had slightly reduced purity (96.8%) as compared to that obtained using the combined heat and microwave treatments. The combination of both treatments with flotation facilitated selective and sustainable separation of PVC and ABS from WEEE plastics to improve their recycling quality.