Pathways to evaluate and improve the sustainability of plastics – an overview

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Plastics in the context of the circular economy and sustainable plastics recycling: Comprehensive review on research development, standardization and market

The purpose of this study is to review existing recycling technologies, standards and market situation for plastics recycling. The principal results show that mechanical recycling is the most well-developed recycling approach in terms of industrial feasibility. This approach enables development of plastic recyclates of various quality levels. At the same time, transfer of many research findings into practice is hindered due to the global plastic material flow, strongly differing regional waste management systems and lack of international recycling standards. This review shows that the development of a Circular Economy Model for plastics products requires close cooperation of scientists with standardization committees and industry

Thermal and Mechanical Properties of the Recycled and Virgin PET—Part I

In various countries, polyethylene terephthalate (PET) represents one of the plastics with a very high recycling rate. Since currently there is no analytical method enabling direct distinction between recycled PET (rPET) and virgin PET (vPET), there are various attempts to differentiate these materials indirectly. One of these approaches claims that the recycling of PET leads to polymer chain degradation, which is reflected in changed thermal, mechanical and crystalline properties, and testing of these properties can therefore be used to distinguish rPET and vPET. However, there are many sources leading to changes in the molecular structure and consequently to the changes of the above-mentioned properties of the PET. The purpose of this study is to analyze the glass transition and melting temperature, degree of crystallinity as well as bending and impact properties of 20 different commercially available PET recyclates from 14 suppliers and evaluate the results with respect to the literature values for vPET. The main results of this study show that the range of vPET properties is so broad that all of the corresponding properties of the tested rPET lie within this range

Recyclable, but not recycled—an indicator to quantify the environmental impacts of plastic waste disposal

With an exponential increase in the production and consumption of plastic products over the last few years, the predominantly linear (take-make-dispose) economy of the plastic life cycle has captured global attention. Even though plastic products offer versatile benefits with their properties across different sectors, with a global recycling rate of less than 10%, it is challenging to reduce the pollution generated by plastic waste. Also, the loss of resources due to the uncontrolled disposal of plastic waste has been projected to cause long-term negative effects on the environment. To ensure a better circularity of the plastic flows across the world, it is essential to design plastic products that have an adequate infrastructure to recover and recycle the waste no matter where they are used. The polymer manufacturers and the plastics converters must account for the environmental impacts of the resources lost in the environment due to the lack of recycling infrastructure as a part of Extended Producer Responsibility. This study introduces an indicator that accounts for the loss of resources and proposes for a better methodology to quantify the environmental impacts of polymers and plastic products, based on their recyclability and the availability of recycling infrastructure to handle them. By integrating the loss of resources with the environmental impacts of specific polymers used in specific plastic products, the stakeholders across the value chain have the choice to select the polymers and products that are actually recycled, thereby reducing their environmental impacts and increasing the circularity

Accelerated ageing of surface modified flax fiber reinforced composites

The overall aim of this study is to evaluate application-oriented potential of biocomposites made of surface-modified flax fibers for use in engineering thermoplastics. The scope of the study includes analysis of the effect of a partially bio-based epoxy-coating, a silane treatment and a combined epoxy-coating / silane treatment of the flax fibers on the mechanical behavior of biocomposites after thermo-oxidative aging. The treated flax fabrics were subjected to tensile tests as well as scanning electron microscopy (SEM) to compare their mechanical behavior and fracture surface. The natural fiber reinforced biocomposites were manufactured through film-stacking of the treated fabrics and polyamide 6 (PA6) using hot-pressing. The durability of the biocomposites after climate-change tests was confirmed via tensile and bending testing. The results show beneficial mechanical behavior of treated fabrics and corresponding biocomposites, but also negative affected durability of treated composites after climate-change tests. Treatment of the fabrics with subsequent accelerated aging leads to a similar low level of tensile and bending moduli

Social Life Cycle Assessments: A Review on Past Development, Advances and Methodological Challenges

Society’s interest in social impacts of products, services and organizational behaviors is rapidly growing. While life cycle assessments to evaluate environmental stressors have generally been well established in many industries, approaches to evaluate social impacts such as Social Life Cycle Assessment (S-LCA) lack methodological consistency and standardization. The aim of this paper is to identify past developments and methodological barriers of S-LCA and to summarize how the automotive industry contributed to the advancement or application of this method. Therefore, a qualitative content analysis of 111 studies published between 2015 and 2020 is used to gather information on past scientific and political milestones, methodological barriers impeding S-LCA and the participation of the automotive sector. The review shows that a broad range of sectors such as the automotive industry contributed to the testing and advancement of S-LCA in the past but that S-LCA remains a young and immature method. Large-scale application is impeded by major barriers such as the variety of impact categories and sub-categories, the lacking integration of the Sustainable Development Goals (SDGs), issues of linking LCA structures to social phenomena or the difficult tracking of social impact pathways. Further research on standardization possibilities, the connection to political social targets and the testing of methods is necessary to overcome current barriers and increase the applicability and interpretability results

Fatigue and fatigue after impact behaviour of Thin- and Thick-Ply composites observed by computed tomography

This study investigates the influence of load ratio and impact damage on the fatigue behaviour of high-performance carbon fibre reinforced polymers (CFRP) with areal fibre weights between 30 gsm and 360 gsm. For undamaged samples, the ultimate tensile and compressive strength, as well as the fatigue properties, are evaluated with regard to their layer thicknesses. The fatigue tests were performed under tension-tension (R=0.1), tension-compression (R=-0.5) and compression-compression (R=10) regime. The results are illustrated as a constant-life diagram, and a piecewise linear interpolation examines a first prediction. The results show that static and fatigue performance improves with decreasing layer thickness. Particularly under tension-compression loading, significant improvements are observed, due to the suppression of matrix cracks and delaminations with thinner layers. In addition, the effect of low-energy impact on the fatigue behaviour of Thin- and Thick-Ply laminates is investigated. The tests demonstrate that although the delamination area is larger, Thin-Ply laminates can sustain higher stresses and still reach the same number of load cycles in contrast to Thick-Ply laminates. Computed tomography measurements visualize 3-dimensional the damage progression after various cycles and prove that the Thin-Ply composites show no increase in the damaged area during fatigue. The interlaminar stress at the delamination is not sufficient for expansion. In contrast, in the case of thicker layers, the damage growths progressively throughout the whole sample with increasing number of cycles. © 2021 The Author(s

Environmental potential of recycling of plastic wastes in Australia based on life cycle assessment

Plastic consumption in Australia is steadily increasing and is estimated to reach 8.8 million tonnes by 2050. Alongside plastic consumption, plastic waste management (PWM) faces rising environmental challenges in Australia as most of them are currently landfilled. Therefore, the Australian government has published a policy to transition to a circular economy as well as a new strategy for PWM with higher recycling rates. To understand the implications of the policy changes and the environmental impacts of End-of-Life (EoL) options, life cycle thinking is necessary. This study evaluates and compares the environmental impacts of the Australian PWM for 2018–2019 to the policy envisaged for 2030 that includes higher recycling rates and waste export bans from a life cycle assessment (LCA) perspective. From the results, it can be seen that the current PWM is majorly linear (take, make, use and dispose) as most of the wastes gets landfilled and exported to other countries but the future PWM strategy for 2030 results in higher resource recovery and significant reduction in the environmental impacts. There is a reduction in Global Warming Potential (GWP) by a factor of almost 10, if the recycling rates increase from 13 to 70%. The state and the federal governments along with other stakeholders need to implement stringent measures to recover plastic wastes if a transition to a circular economy is to happen by 2030

Biobasierte Kunststoffe als Produkt der Bioökonomie

Biobasierte Kunststoffe bieten die Chance, Wertschöpfungsketten so zu gestalten, dass einMehrwert für Mensch, Wirtschaft und Umwelt gleichermaßen generiert werden kann. Voraussetzunghierfür ist ein gezieltes Management der Lieferkette und Transparenz in der Nachhaltigkeitsbewertung

Plastic Packaging Waste Management in Iceland: Challenges and Opportunities from a Life Cycle Assessment Perspective

The management of plastic packaging waste is advancing quickly, and new strategies are being implemented worldwide for better resource recovery. To assess the environmental benefits of new ways of handling plastic packaging waste, we need to first evaluate current waste management options in order to create a basis for comparison. In this study, the environmental impacts of plastic packaging waste handling are assessed for the first time in Iceland using the life cycle assessment (LCA) methodology. The results show that mechanical recycling, despite including the impacts of exporting the waste to different European countries, has more environmental benefits than landfilling the waste in Iceland. Increasing the recycling rates of plastic waste in Iceland is also identified as a promising option from a resource efficiency perspective. With better waste sorting, Iceland can become more environmentally sustainable, ensuring that plastic materials land in recycling processes, and thereby enhancing the flow of material in the circular economy