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    Item type:Publication,
    Screening of the regulations and legislations that control the chemical content of plastics through their lifecycle
    The mechanical recycling of plastic waste plays a crucial role in advancing the circular economy, ensuring that valuable resources within the waste stream are preserved for extended periods. However, the sustainable, economic, and environmentally responsible management of plastic waste remains a significant challenge, particularly when plastics are sourced from contaminated streams, such as those originating from electronic waste (e-plastics). These materials often contain a wide range of chemical substances, some of which can pose considerable environmental and health risks. Therefore, assessing the degree of contamination in plastic waste is essential to ensure a safe and sustainable life cycle for plastics. Regulatory frameworks aim to address this issue by establishing guidelines and limitations on the use of hazardous chemicals, as well as providing standards for the proper treatment of contaminated waste streams. This paper offers a comprehensive review of the regulations and legislation governing the chemical content of plastics throughout their life cycle—spanning from production to waste disposal and recycling. The objective is to deepen the understanding of the challenges and limitations associated with the recycling of e-plastics and to highlight the importance of these regulatory measures in achieving sustainable plastic waste management.
    Publicationtype: Book Part
      54
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    Item type:Publication,
      51
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    Item type:Publication, Access status: with files ,
    Overlooked Impact of Moisture on the Stability of Printing Ink and Its Impact on Recycled Low-Density Polyethylene (LDPE) Quality
    (Multidisciplinary Digital Publishing Institute (MDPI), 2024-11-21) ; ; ; ;
    Printing inks, composed of binders, pigments, and additives, are essential components in plastic packaging but complicate recycling due to plastic contamination and degradation. While polyolefins are resistant to hydrolytic degradation, moisture generated from upstream cleaning processes, which is often ignored, can accelerate the degradation of ink binders, affecting the recyclate quality. This study has examined the impact of 3 wt.% moisture, introduced before extrusion, on the degradation of nitrocellulose (NC), polyurethane (PU), polyvinyl butyral (PVB), and cellulose acetate propionate (CAP) binders mixed with virgin, low-density polyethylene (LDPE) at varying concentrations to simulate contamination levels. Control samples were prepared by extrusion under dry conditions and using p-xylene to compare with degradation-free conditions. Analyses, including the measurement of the melt–flow index (MFI), tensile testing, FTIR (Fourier transform infrared spectroscopy), TGA (thermogravimetry analysis), and gas chromatography mass spectroscopy (GC-MS) have established that NC is fully degraded, causing discoloration and altering the MFI. Moreover, PU degrades mainly in the presence of moisture, contrary to previous findings. In contrast, PVB does not degrade but exhibits modified mechanical properties; whereas, CAP shows minimal impact. The findings of this research demonstrate the critical role of moisture in determining recyclability, informing strategies for ink selection and recycling processes to facilitate plastic packaging circularity.
    Publicationtype: Journal Article
      42  25
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    Item type:Publication, Access status: with files ,
    Thermal degradation and hydrolysis depolymerization of printing ink components for plastic packaging in recycling processes : a review
    This review covers the decomposition mechanisms of various printing ink binder resins, with a particular focus on their behavior under extrusion conditions in the mechanical recycling process of polyolefin (PO) based plastic packaging. Thermal degradation and hydrolysis of the nitrocellulose (NC) — the most used binder for flexographic surface printing on single-layer flexible plastic packaging, occur concurrently during the mechanical recycling process under 160–210 °C. For other printing ink binders, polyurethane (PU) noticeable degradation takes place between 200 and 300 °C, mostly above 250 °C. However, with the involvement of humidity, degradation by hydrolysis can start from 150 °C. A similar effect is also discovered with the cellulose acetate (CA) derivatives, which are thermally stable until 300 °C and can be hydrolyzed at 100 °C. The thermal stability of polyvinyl butyral (PVB) is not influenced by humidity, with thermal stability ranging from 170 to 260 °C, depending on different types. Ultraviolet (UV)-cured acrylics are thermally stable until 400 °C. The hydrolysis degradation can take place at room temperature. Moreover, this review covers the thermal stability of different colorants used for printing ink application and elaborates on several thermal-stable alternatives of some common colors. This study further reviews how the binder resin affects the quality of recyclates, revealing it to be not only induced by the degradation of the binder resin but also by the immiscibility between the plastic and binder resin. In advanced recycling processes, mainly selective dissolution-precipitation and pyrolysis, the presence of binder resin and its degradation products could still affect the quality of the product. This review accentuates the imperative need for in-depth research to unravel the impact of printing ink constituents on the quality of recycled products. (Figure presented.)
    Publicationtype: Review Article
      32  32
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    Item type:Publication, Access status: with files ,
    Lab-scale and full-scale industrial composting of biodegradable plastic blends for packaging
    Background: The acceptance of compostable plastic packaging in industrial composting plants is not universal despite available certification due to the persistence of plastic residues after composting. To better understand this discrepancy, this study compared the disintegration rates of two blends designed for rigid packaging (polylactic acid based) and soft packaging (polybutylene succinate based) in lab-scale composting tests and in an industrial composting plant. Methods: A lab-scale composting test was conducted in triplicates according to ISO 20200 for 4, 8 and 12 weeks to check the disintegration potential of the blends. Duplicate test material were then exposed in the compost pile of an industrial composting plant for a duration of 3 weeks and compared with a supplementary lab-scale test of the same duration. Results: The rigid packaging samples (1 mm thickness) retained on average 76.4%, 59.0% and 55.7% of its mass after 4, 8 and 12 weeks respectively in the lab-scale. In the plant, the average remaining mass was 98.3%, much higher compared to the average of 68.9% after 3 weeks in the supplementary lab-scale test. The soft packaging samples (109±9 µm sample thickness) retained on average 45.4%, 10.9% and 0.3% of its mass after 4, 8 and 12 weeks respectively in the lab-scale. In the plant, a high average remaining mass was also observed (93.9%). The supplementary lab-scale test showed similar remaining mass but higher fragmentation after 3 weeks. Conclusions: The results show that the samples achieved significant disintegration in the lab-scale but not in the plant. The difference between the tests that might further contribute to the differing degradation rates is the composition and heterogeneity of the composting substrate. Therefore, the substrate composition and thermophilic composting duration of individual plants are important considerations to determine the suitability of treating compostable plastic in real-world conditions.
    Publicationtype: Journal Article
      39  124
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    Item type:Publication, Access status: with files ,
    Screening the impact of surfactants and reaction conditions on the de-inkability of different printing ink systems for plastic packaging
    (Molecular Diversity Preservation International, 2023-05-08) ; ; ; ;
    One of the major applications (40% in Europe) of plastic is packaging, which is often printed to display required information and to deliver an attractive aesthetic for marketing purposes. However, printing ink can cause contamination in the mechanical recycling process. To mitigate this issue, the use of surfactants in an alkaline washing process, known as de-inking, has been employed to remove printing ink and improve the quality of recyclates. Despite the existence of this technology, there are currently no data linking the de-inking efficiency with typical printing ink compositions. Additionally, it is necessary to investigate the de-inking process under the process parameters of existing recycling plants, including temperature, NaOH concentration, and retention time. This study aims to evaluate the performance of commonly used printing inks with different compositions under various washing scenarios for plastic recycling in conjunction with different de-inking detergents containing surfactants or mixtures of surfactants. The results indicate that the pigments applied to the ink have no significant effect on the de-inking process, except for carbon black (PBk 7). Nitrocellulose (NC) binder systems exhibit high de-inkability (over 95%) under the condition of 55 °C and 1 wt.% NaOH. However, crosslinked binder systems can impede the de-inking effect, whether used as a binder system or as an overprint varnish (OPV). The de-inking process requires heating to 55 °C with 1 wt.% NaOH to achieve a substantial effect. Based on the findings in this work, breaking the Van der Waals forces, hydrogen bonds, and covalent bonds between the printing ink and plastic film is an essential step to achieve the de-inking effect. Further research is needed to understand the interaction between surfactants and printing inks, enabling the development of de-inkable printing inks and high-performance surfactants that allow for de-inking with less energy consumption. The surfactant and NaOH have a synergistic effect in cleaning the printing ink. NaOH provides a negative surface charge for the adsorption of the cationic head of the surfactant and can hydrolyze the covalent bonds at higher concentrations (>2 wt.%).
    Publicationtype: Journal Article
    Scopus© Citations 2  64  455
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    Item type:Publication, Access status: with files ,
    Degradation of thermoplastic cellulose acetate-based bioplastics by full-scale experimentation of industrial anaerobic digestion and composting
    The ability of full-scale industrial plants to degrade bioplastics waste must be verified to exclude any negative effects on the quality of the process outputs. This study aims to assess the degradation of two thermoplastic cellulose acetate-based bioplastics, in pure and composite forms in both Anaerobic Digestion (AD) and Composting (C) industrial conditions. The main degradation occurred during AD, where a disintegration of about 36% and 50% was achieved from pure and composite thermoplastic cellulose acetate, respectively. The disintegration during C did not exceed 20% for both samples. The combined process resulted in a slightly higher degradation (58–40%) than that obtained in AD, revealing how the main alteration of samples occurred in an anaerobic environment. Despite this macroscopic degradation, the samples showed only minor superficial degradation as highlighted from SEM analysis. FT-IR spectroscopy, TGA andDSC analyses showed that the biodegradation mechanism involved mainly the plasticizer loss and deacetylation of the cellulose matrix, with only partial degradation of cellulose backbone However, both deacetylation and degradation were favored in AD and AD + C processes and from the presence of filler in anaerobic conditions. These results demonstrated how the degradation obtained on an industrial scale can differ significantly from those obtained in the laboratory scale, especially for pure thermoplastic cellulose acetate. Furthermore, current industrial AD and C process resulted not optimized for the treatment of thermoplastic cellulose acetate-based bioplastics. Hence, this works could help waste facilities managers to process emerging materials such as bioplastics in a more sustainable way.
    Publicationtype: Journal Article
      43  25
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    Recycling of polyolefin packaging for food applications : requirements and gaps
    (Eurowaste Srl, 2023) ;
    Publicationtype: Conference Paper
      96
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    Challenges and strategies for bio-based and biodegradable plastic waste management in Europe
    (Multidisciplinary Digital Publishing Institute (MDPI), 2022-12-09) ; ; ; ;
    In recent years, an increasing trend towards replacement of conventional fossil-based plastics with bio-based plastics was noticed, i.e., production of plastics partly or fully made from biomass is rapidly expanding. Currently, bio-based and biodegradable plastics have a very small market size, approximately only 1% of all plastics produced. However, the forecast of the global bioplastics production capacities predicts an increase from approximately 2.417 million tonnes in 2021 to approximately 7.593 million tonnes in 2026, more than three times the current capacity. Therefore, it is necessary to assess the challenges and identify the barriers for bio-based and biodegradable plastics for waste management and to evaluate the effectiveness of current plastic waste management strategies for the efficient waste management of bio-based and biodegradable plastics. The main barriers and motivators of the biodegradable and biodegradable plastics market that have been identified include macroeconomic factors, regulatory factors, technological factors, and social factors. The bio-based and biodegradable plastics have to be separately collected and treated under mostly controlled, regulated conditions. However, currently, there are no legal provisions providing for the separate collection of bio-based plastics, leading to their disposal with either hazardous waste, conventional plastics, or municipal waste. Since the effective plastic waste management strategy relates to good performance in each step of the waste management process, bio-based and biodegradable plastic waste management could, therefore, be based on an effective strategy for the management of plastic waste. However, there is a need for standardizing waste collection systems and creating a harmonized waste collection infrastructure, which would lead to effective sorting of bio-based plastic waste.
    Publicationtype: Journal Article
    Scopus© Citations 8  139  317
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    Quality changes of low-density polyethylene (LDPE) recyclates from the pretreatment process with a cationic surfactant and a nonionic surfactant as cleaning agents upstream of extrusion
    (Multidisciplinary Digital Publishing Institute (MDPI), 2022-10-24) ; ; ; ;
    Low-density polyethylene is the most applied packaging plastic. The recycling rate of LDPE is low, especially for the material from the post-consumer source. The quality of the LDPE post-consumer recyclates is influenced by different contaminations, either intentionally or non-intentionally. Printing ink is one of the substances that is regarded as having a negative influence on the quality of LDPE recyclates. This study used a new type of nonionic surfactant oxirane, methyl-, polymer for de-inking as a pretreatment. Afterward, the LDPE film flakes were mechanically recycled in the laboratory. A melt flow index (MFI), differential scanning calorimetry (DSC), and tensile strength analysis were carried out. This work reported the de-inking effect of a new type of nonionic surfactant. However, no evidential correlation between the rate of color removal and the improvement in the rheological, thermal, and mechanical properties can be identified from the result of this study.
    Publicationtype: Journal Article
    Scopus© Citations 2  120  278