An experimental validation of diffusion-based devolatilization models in extruders using post-industrial and post-consumer plastic waste

The recycling of packaging waste is an important part of the EU circular economy package, with a political focus on raising the recycling targets for post-consumer plastic packaging waste (PPW). The recycling of PPW involves at least three steps; collection, sorting and mechanical recycling. In contrast to the first two steps, mechanical recycling is poorly documented, as it is considered a free market activity. In order to provide a complete chain description the mechanical recycling yields were determined. The recovery of mass was determined for the main plastic sorting products from both major collection systems: separate collection (SC) and mechanical recovery (MR) from municipal solid waste. This technical assessment was conducted with a laboratory set-up for a standard mechanical recycling process. This analysis showed that there is a substantial sample-to-sample variation in polymeric composition between similar feedstocks and this variation is also observed in recovered masses. Next, the mechanical recycling of polyethylene feedstocks was studied more in depth. Six PE feedstocks with a gradual increasing level of complexity (from only transparent PE bottle bodies to the complete PE sorting product according to DKR 329), were prepared and mechanical recycled with the laboratory set-up. Since the polymeric composition of both the six feedstocks and the six floating milled goods were known, the net PE recycling yield could be calculated. The net PE yields are close to 100% for such a standard recycling process. Additionally, the compositional analysis revealed that contaminants are only partially removed by the standard mechanical recycling process.

A real case study of mechanical recycling as an alternative for managing of polyethylene plastic film presented in mixed municipal solid waste

This paper is the third in a series that examines critical factors in the sustainable recycling of plastics from end-of-life (EOL) electrical and electronic equipment (EEE). Previous papers provided an overview of the subject (Sustainable electrical and electronic plastics recycling, ISEE 2004) and the role of energy recovery (Energy recovery in the sustainable recycling of plastics from electrical and electronic products, ISEE 2005). The present paper draws from the earlier papers and explores the role of feedstock (chemical) recycling. In general, plastics recovery consists of two basic process types - material recovery and energy recovery. Two categories of material recovery are of principal interest, mechanical recycling and feedstock recycling. Mechanical recycling reprocesses post-use plastics to plastic recyclates (secondary plastic materials). Feedstock recycling, sometimes referred to as chemical recycling, is the process that converts plastics back to basic petrochemical feedstocks for use by industry in the form of syn crude, process chemicals, or fuels. Feedstock recycling can be broken down into pyrolytic liquefaction; gasification, including the case where the chemical content of the plastics becomes an integral part of an industrial process such as ferrous and non-ferrous metal smelting (reduction processes); hydrogenation processes; and chemical recycling back to reactive monomers or high value oligomers. Feedstock recycling of plastics, although still largely developmental, is being evaluated on a large scale in the United States, Europe, China, and Japan. The plastics industry is actively engaged in R&D. Feedstock recycling technologies can both recover valuable materials and manage substances of concern in an environmentally sound manner. Feedstock recycling technologies have the potential to significantly increase the sustainable recovery of plastics from EOL EEE beyond what can be achieved using mechanical recycling and energy recovery

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.

This paper presents a review of waste disposal methods for fibre reinforced polymer (FRP) materials. The methods range from waste minimisation, repurposing, reusing, recycling, incineration, and co-processing in a cement plant to dumping in a landfill. Their strength, limitations, and key points of attention are discussed. Both glass and carbon fibre reinforced polymer (GFRP and CFRP) waste management strategies are critically reviewed. The energy demand and cost of FRP waste disposal routes are also discussed. Landfill and co-incineration are the most common and cheapest techniques to discard FRP scrap. Three main recycling pathways, including mechanical, thermal, and chemical recycling, are reviewed. Chemical recycling is the most energy-intensive and costly route. Mechanical recycling is only suitable for GFRP waste, and it has actually been used at an industrial scale by GFRP manufacturers. Chemical and thermal recycling routes are more appropriate for reclaiming carbon fibres from CFRP, where the value of reclaimed fibres is more than the cost of the recycling process. Discarding FRP waste in a sustainable manner presents a major challenge in a circular economy. With strict legislation on landfill and other environmental limits, recycling, reusing, and repurposing FRP composites will be at the forefront of sustainable waste-management strategies in the future.

The increase in waste has motivated the adoption of the circular economy concept, which assumes particular relevance in the case of plastic materials. This has led to research of new possibilities for recycling plastics after their end-of-life. To achieve this goal, it is fundamental to understand how the materials’ properties change after recycling. This study aims to evaluate the thermal and mechanical properties of recycled plastics, namely polycarbonate (PC), polystyrene (PS), glass fibre-reinforced polyamide 6 (PA6-GF30), and polyethylene terephthalate (PET). With this purpose, injected samples were mechanically recycled twice and compared through thermal and mechanical tests, such as differential scanning calorimetry, hardness, tensile strength, and the melt flow rate. The results show that the amorphous materials used do not suffer significant changes in their properties but exhibit changes in their optical characteristics. The semicrystalline ones present some modifications. PET is the material that suffers the biggest changes, both in its flowability and mechanical properties. This work demonstrates that the mechanical recycling process may be an interesting possibility for recycling depending on the desired quality of final products, allowing for some materials to maintain comparable thermal and mechanical properties after going through the recycling process.

<title>Abstract</title> The accumulation of plastic waste poses serious environmental problems worldwide. Nigeria has an annual production rate of about 32 million tons of solid waste, that is 67% of the total solid waste produced in Sub-Saharan Africa. Recycling plastic waste into construction materials is a potential solution to achieving a circular economy, which will mitigate both the crisis in waste management and ensure a sustainable supply of building materials. This paper evaluated the potential of the plastic waste recycling business in Nigeria in terms of capacity to collect waste, the technological capacities, market preparedness and limitations of this business to generate environment-friendly construction materials. The study used purposive sampling, and eight plastic recycling enterprises were selected in six states in Nigeria (Bauchi, Akwa Ibom, Lagos, Kwara, Kaduna, and Ondo) and the Federal Capital Territory, Abuja, in June to August 2025. All these companies process 221 tons of plastic waste every month. We gathered data using structured questionnaires (39 questions on 10 domains), visiting the field, and semi-structured interviews with the senior management. Analysis was used in terms of descriptive statistics and frequency distributions and Exact Tests by Fisher to test categorical associations. The surveyed companies (100%) used only mechanical recycling, where HDPE (87.5%), PET (87.5%), and LDPE (75%) as the main recycling processes. There is only one company (12.5%) that manufactures construction materials (floor tiles) at the moment, but half of the eight intend to enter the market. Significant operational issues are waste contamination (87.5%), high costs of operation (75%), and transportation problems (75%). The statistical analysis showed that there was a significant correlation between the processing of water sachets and the intention to venture into the production of construction materials (Fisher Exact Test, p = 0.028, Cramer V = 0.775). Nevertheless, two-thirds of firms were positive about the prospects of the industry within five years, which was fuelled by increased environmental concern and innovative potential. The plastic recycling industry in Nigeria has a lot of potential, although it is still in its infancy. The industry needs to upgrade the technology over and above the mechanical recycling, better waste sorting systems, a policy supportive environment, and capacity building. The companies acknowledge several positive consequences on the environment (reduction of landfills, mitigation of ocean pollution, resource preservation) and express great interest in the collaborative networks (100%). The growth and environmental contribution of the sector and other strategic interventions, such as technology transfer, regulatory development and facilitation of markets could be increased.

Plastics are everywhere in modern society. Their versatility has made them the materials of choice for many different kinds of products and applications, making possible the advent of an unprecedented single-use economy. Just a few plastic types dominate the world’s plastic consumption and none of these have been designed to be recycled. Today, plastic accumulation in environment is profoundly threatening and disrupting ecosystems around the globe. Mechanical recycling has emerged as a straightforward strategy for recycling plastics. However, it shows limitations, typically when applied for polyolefins. Chemical recycling strategies are emerging and are now opening new possibilities for recycling, but at higher energy costs. Learning from these industrial realities, this chapter draws attention to the opportunities of innovation in polymer science presented by dynamers to design new polymers fit for circular use. Dynamers can be designed to present features such as self-healing and enhanced mechanical and chemical recyclability, thus conferring to plastics long service lives. We present some chemistries and we project how to implement them through the value chain to enhance plastic recyclability. There is no doubt there are challenges to be overcome before their industrialization, however we consider the potential of dynamers to become the material of choice in a circular economy.

Vitrimerization as a bridge of chemical and mechanical recycling

The immense utilization of plastics has produced an enormous amount of plastic waste. So, basically there is a necessity created for proper method for plastic waste management. As, we know plastics is the most essential part of our life and used in every application and has a very versatile portfolio used everywhere from industries to households. We can say that the use of plastics is inevitable. In the present time adoption of sustainability principles including selection of the best recycling process is important for optimum utilization of the resources. As there are various plastic waste management strategies available, their prioritization on the basis of several criteria like health, safety, the environment impact, etc. is relevant for the stakeholders involved in this sector . Main objective as to apply by using different criteria as multi- criteria decision making to conduct an analysis which are based on a hierarchical structure that is multi-level and analysis of plastic waste management methods. The AHP approach is a (MCDM) tool which we adopt in our study to depict the best suitable method for the Plastic Waste Management for the industries. As the identification of criteria for the plastic recycling process based on the literature review and expert discussions was done for this the study was initiated. Further, the weightage of different criteria and ranking of the available methods were done using AHP. Four commonly used plastic waste management alternatives were evaluated and findings reveal that recycling is the best alternative. This study will help the industries in selection of best possible techniques and methods for plastic waste management. By this deep study we will be able to find out the best method which can be used for plastic waste management and AHP approach gives us a clarity and it takes various attributes to reach out to a result. This technique is inter-related to Operation Research subject. From this paper we can conclude that out of Incineration, landfilling, Mechanical Recycling and Road filling , Mechanical Recycling comes out to be the best method that can be used for Plastic Waste Management and it should be mainly utilized further.

Plastics and climate change—Breaking carbon lock-ins through three mitigation pathways

In the plastics industry it has been common practice to mechanically recycle waste material arising from a production. However, mechanical recycling affect material mechanical properties and consequently quality of the end products; therefore it needs to be quantified.

The rapid growth of the wind energy industry has resulted in a significant increase in Wind Turbine Blade (WTB) waste, posing challenges for recycling due to the composite materials used in their construction. Several proposed techniques, including mechanical, thermal, and chemical processes, have been considered for wind-blade recycling, but determining the most effective approach remains a critical issue. This study presents the first comprehensive systematic review of available wind-blade recycling processes, evaluating their economic, technical, and environmental performance. Additionally, we consider the physical and mechanical properties of the recycled materials, which can aid in identifying potential markets for these materials. Among the various recycling technologies, microwave pyrolysis emerges as the most promising technique for recycling large quantities of WTB, despite some challenges and uncertainties surrounding its effectiveness and feasibility at an industrial scale. However, the optimal recycling technique for WTB will depend on multiple factors, including the blade material, the desired environmental impact, and the economic feasibility of the process. Based on this review, mechanical recycling appears to be more energy-efficient, while the fluidised bed recycling process demonstrates a lower primary energy demand, global warming potential, and power consumption. These findings provide valuable guidance for decision-makers in the wind energy industry to develop effective waste management strategies and plans for sustainable wind energy development. Addressing WTB waste and implementing efficient recycling techniques will be critical in mitigating environmental impacts and promoting sustainability in the renewable energy sector as the wind energy industry grows.

Plastic is highly durable, strong, elastic, and less expensive to produce, and widely used globally. The result of excessive use causes a high accumulation of plastic waste for communities in developing countries Like Egypt. Egypt is one of the largest countries in population in Africa and the middle east. According to Environments Affairs Agency (EEAA), Egypt produces over 22 million tons of municipal waste per year, and waste plastic represents 13% of the total waste. Therefore, plastic recycling is critical in our life. But mechanical recycling is unable to recycle all plastic, as it is an expansive and challenging process. It exhibits a series of degenerated properties like lowering the impact resistance characterizers of polymers. The second recycling process is chemical methods and thermochemical recycling. Thermochemical degradation has a promising substitutional for recycling polymers. For example, pyrolysis can deal with high molar mass organic molecules since the plastic owns a calorific value comparable to fuel. Energy Recovery from waste Plastic using the thermal treatment for plastics as incineration, gasification, and pyrolysis represents a suitable process as discussed. So, the fuel production from pyrolysis polymer would be a better and more promising alternative for a country like Egypt.

Predicting the long-term performance of pavement structures is crucial for efficient infrastructure management, but uncertainties in material properties, traffic loads, and environmental conditions pose significant challenges. This research introduces a novel reliability model for pavement performance prediction using Quasi-Monte Carlo (QMC) simulation. Unlike traditional Monte Carlo methods, QMC employs deterministic sequences for enhanced sampling efficiency and accuracy in estimating probabilistic quantities like reliability indices and probabilities of failure. The study investigates the impact of QMC on pavement performance predictions, considering uncertainties in traffic load repetitions, fatigue life, and rutting life. The QMC approach demonstrates superior performance by producing stable mean estimates and significantly narrowing confidence intervals as sample size increases. This research highlights the advantages of QMC simulation in probabilistic pavement design, offering a computationally efficient framework for robust and reliable performance predictions. The findings support QMC as a valuable tool for achieving durable, safe, and cost-effective pavement infrastructure.