Plastic Products Research Articles

Nanoplastic Contamination in Freshwater Biofilms Using Gel Permeation Chromatography and Plasmonic Nanogold Sensor Approaches.

The worldwide contamination of aquatic ecosystems by plastics is raising concern, including their potential impacts on the base of the food chain, which has been poorly documented. This study sought to examine, for the first time, the presence of nanoplastics (NPs) in biofilms from freshwater streams/rivers. They were collected at selected polluted sites, such as the industrial sector for plastic recycling and production, miscellaneous industries, agriculture, municipal wastewaters/effluents and road runoffs. In parallel, the functional properties of sampled biofilms were determined by proteins, lipids, esterase (lipase), viscosity and oxidative stress. The results revealed that biofilms collected at the plastic industries and road runoffs contained the highest NP levels based on size exclusion chromatography, fluorescence detection and a new nanogold sensor visualization method. Examination of the chromatographic elution profiles showed increased abundance and size of NPs in the 10-150 nm size range at the polluted sites. Biofilms from the plastic industry site had elevated levels of aldehydes (oxidative stress) and lipids compared to the other sites. Biofilms collected at the municipal sites had elevated levels of proteins and esterases/lipases, with a decrease in total lipids. Biofilms collected at agriculture sites had the lowest levels of NPs in this campaign, but more samples would be needed to confirm these trends. In conclusion, biofilms represent an important sink for plastics in freshwater environments and display signs of distress upon oxidative stress.

Are micro/nanorobots an effective solution to eliminate micro/nanoplastics in water/wastewater treatment plants?

The extensive production and widespread use of plastic products have resulted in the gradual escalation of plastic pollution. Micro/nano/plastic pollution has become a global issue, and addressing how to “green” remove them is a crucial topic that needs to be tackled at this stage. Recently, micro/nanorobots have offered a promising solution for improving water monitoring and remediation as an environmentally friendly remediation strategy. Micro/nanorobots have been proven to efficiently remove micro/nanoplastics from water bodies. Micro/nanoplastics are captured by micro/nanorobots in water through electrostatic adsorption and electrophoretic interactions, and separation is achieved under the action of an external transverse rotating magnetic field. Their small size enables them to navigate easily in complex environments, while magnetic and optical drives help them move along established routes and reach different areas. With the assistance of these innovative robots, diffusion-limited reactions can be overcome, allowing for active contact with target pollutants. However, research on the removal of micro/nanoplastics by micro/nanorobots is still in its early stages. The dependence on chemical fuels and high costs severely limit the development and application of micro/nanorobots. Micro/nanoplastics are frequently captured by micro/nanorobots, but the degradation efficiency of micro/nanoplastics remains very low. Additionally, the secondary pollution caused by micro/nanorobots is also a key factor limiting their implementation. Although micro/nanorobots are a very promising technology for removing micro/nanoplastics, they still need to be explored in their applications. This paper discusses the opportunities and challenges faced by micro/nanorobots in removing micro/nanoplastics. Development and application of self-driven intelligent micro/nanorobots will help expedite the eco-friendly removal of micro/nanoplastics and other emerging pollutants.

BPA exposure and Se deficiency caused spleen damage in chickens by nitrification stress-TNF-α

With the increasing production and demand of plastic products in life, inescapable bisphenol A (BPA) exposure results in a threat to the health of organisms. Selenium (Se) is an essential trace element for living organisms. The insufficient Se intake can cause multi-tissue organ damage. In the process of production and life, the exposure of BPA is usually accompanied by Se deficiency. In this study, the models of chicken with BPA exposure and/or Se deficiency was duplicated, the status of nitrification stress, apoptosis, necroptosis, and changes in TNF-α/FADD signaling pathways in chicken spleen were examined. At the same time, nitrification stress inhibitor and TNF-α inhibitor were introduced into MSB-1 cell model tests in vitro, indicating that BPA exposure and Se deficiency up-regulated TNF-α/FADD signaling pathway through nitrification stress, inducing necroptosis and apoptosis, and heat shock protein was also involved in this process. This study provides a new control idea for healthy poultry breeding based on Se, and also provides a new reference for toxicity control of environmental pollutants.

Analysis of Extrusion Blow Molding Machine Maintenance Planning with Reliability Centered Maintenance and IRRO Method

High demand for plastic products from year to year creates the need for plastic molding machines that can mass produce plastic products. An example of a plastic molding machine used at PT. X is a VK type extrusion blow molding (EBM) machine. Based on data from PT. X, the downtime of the VK type EBM machine reached 215.74 hours in 2021-2023. Therefore, improvements are needed in the machine maintenance management system. The purpose of this research is to determine the critical components, determine the reliability value of the critical components, and also establish a preventive maintenance schedule along with a cost budget plan for each critical component of the VK type extrusion blow molding machine at PT. X to increase the effectiveness of existing production activities. The method used is Reliability Centered Maintenance (RCM) with the application of RCA and FMEA methods to find critical components, then calculate the reliability of critical components as a reference for making preventive maintenance schedules. The data used are the failure data of VK type EBM machine in 2021-2023 period. The results of this study obtained 4 critical components with a reliability value of 0.5, namely the clamping unit at 210.3149 hours, the cutting unit at 79.9911 hours, the head unit at 677.5324 hours, and the hydraulic unit at 424.1550 hours. Maintenance planning is based on the IRRO (Inspection, Repair, Replace, Overhaul) method. The total maintenance cost for the period 2025 is Rp 35,093,903, which reduces the cost by 8.5% compared to 2023.

Life Cycle Analysis Study of Plastic Flower Pot Products

Some flower pots are made of plastic materials. Plastic waste is a global environmental issue with varying quantities and types in different countries. One source of plastic pollution is low-durability plastic pots, commonly used for seeding in agriculture, horticulture, and forestry. Waste from these plastic pots is difficult to decompose by soil microbes, thus posing an environmental contamination risk. Life Cycle Analysis (LCA), also known as life cycle assessment, is a method to measure the environmental impacts of products, such as biofuels. In LCA, researchers prepare an inventory of the resources used (e.g., fossil fuels and raw materials) and substances produced (e.g., greenhouse gases, solid waste, and other pollutants) throughout the full life cycle of production, transportation, and use of the product in question. From this inventory, researchers conduct impact assessments that estimate the final effects on human health, ecosystem function, and depletion of natural resources. This study aims to assess the life cycle analysis of plastic flower pot products from their initial material stage to their disposal as waste, in order to gain insights into the potential for minimizing their environmental impact. The results of research where the production of 600 ml plastic flower pot bottles required 28 grams of plastic resin per bottle, as well as energy for the production and transportation processes. Plastic packaging production produces defective products.

Insight into the fate of bioplastic and similar plant-based material debris in aquatic environments via continuous monitoring of their leachate composition – Release of carbon, metals, and additives

Currently, the environmental problems associated with plastic production and waste, such as the consequences of worldwide pollution of natural waters with microplastics, have led to the seeking of alternative materials that can at least partially replace conventional petroleum-based plastics. Substitute materials include bioplastics and similar plant-based materials or their composites. However, their fate when disposed of in unintended environments (e.g., water bodies) remains largely unknown, while such information is highly desirable prior to massive expansion of exploiting such materials. This study aims to contribute filling this knowledge gap. Specifically, 19 different types of bioplastic and similar plant-based material debris (corresponding to the size of microplastics) were kept in long-term contact with water to mimic their behaviour as water pollutants, and the leachates were continuously analysed. Eighteen of the 19 investigated materials released significant amounts of dissolved organic carbon—up to 34.0 mg per g of debris after 12 weeks of leaching. Each leachate also contained one or more of the following elements: Al, B, Ba, Ca, Fe, K, Mg, Mn, N, Na, P, Si, Ti, and Zn. Non-targeted analysis aimed at providing more specific insight into the leachate composition tentatively revealed 91 individual chemicals, mostly fatty acids and other carboxylic acids, phthalates, terephthalates, adipates, phenols, amides, alcohols, or organophosphates. Based on the compound characteristics, they might be additives, non-intentionally added substances, as well as their degradation products. In general, the current results imply that bioplastics and similar plant-based materials should be considered complex materials that undergo industrial processing and comprise additives rather than harmless natural matter. Additionally, various compounds can release from the bioplastic and similar plant-based material debris when deposited in water. It might have consequences on the fluxes of carbon, metals and specific organic contaminants, and it resembles some properties of conventional petroleum-based microplastics.

Nationwide meta-analysis of microplastic distribution and risk assessment in China's aquatic ecosystems, soils, and sediments

Microplastic (MP) accumulation has recently become a pressing global environmental challenge. As a major producer and consumer of plastic products, China’s MP pollution has garnered significant attention from researchers. However, accurate and comprehensive investigations of national-level MP pollution are still lacking. In this study, we systematically collated a national MP pollution dataset consisting of 7766 water, soil, and sediment sampling sites from 544 publicly published studies, revealing the spatiotemporal distribution and potential risks of MP pollution in China. The results indicate that MP distribution is influenced by various regional factors, including economic development level, population distribution, and geographical environment, exhibiting considerable range and complexity. MP concentrations are generally higher in economically prosperous areas, but the degree of pollution varies significantly across different environmental media. Given the uncertainty and lack of standardized data in traditional microplastic risk assessment methods, this article highlights the urgency of developing a comprehensive big data and artificial intelligence (AI)-based regulatory framework. This work provides a substantial amount of accurate MP pollution data and offers a fresh perspective on leveraging AI for microplastic pollution regulation.

A Valuable Source of Promising Extremophiles in Microbial Plastic Degradation.

Plastics have accumulated in open environments, such as oceans, rivers, and land, for centuries, but their effect has been of concern for only decades. Plastic pollution is a global challenge at the forefront of public awareness worldwide due to its negative effects on ecological systems, animals, human health, and national economies. Therefore, interest has increased regarding specific circular economies for the development of plastic production and the investigation of green technologies for plastic degradation after use on an appropriate timescale. Moreover, biodegradable plastics have been found to contain potential new hazards compared with conventional plastics due to the physicochemical properties of the polymers involved. Recently, plastic biodegradation was defined as microbial conversion using functional microorganisms and their enzymatic systems. This is a promising strategy for depolymerizing organic components into carbon dioxide, methane, water, new biomass, and other higher value bioproducts under both oxic and anoxic conditions. This study reviews microplastic pollution, the negative consequences of plastic use, and the current technologies used for plastic degradation and biodegradation mediated by microorganisms with their drawbacks; in particular, the important and questionable role of extremophilic multi-enzyme-producing bacteria in synergistic systems of plastic decomposition is discussed. This study emphasizes the key points for enhancing the plastic degradation process using extremophiles, such as cell hydrophobicity, amyloid protein, and other relevant factors. Bioprospecting for novel mechanisms with unknown information about the bioproducts produced during the plastic degradation process is also mentioned in this review with the significant goals of CO2 evolution and increasing H2/CH4 production in the future. Based on the potential factors that were analyzed, there may be new ideas for in vitro isolation techniques for unculturable/multiple-enzyme-producing bacteria and extremophiles from various polluted environments.

Assessing the Effectiveness of the Plastic Ban in the City of Bangalore in Addressing the Market Failure Associated with It

The Bruhat Bengaluru Mahanagara Palike Solid Waste Management (BBMP-SWM) Bye-laws, 2019 was passed by the BBMP in 2019 to ensure proper waste management in the city alongside new rules on the consumption of plastic. According to the Karnataka state plastic board, every citizen, on an average, consumes 16kgs of plastic every month. The extended essay aims towards answering the question “To what extent has the Bruhat Bengaluru Mahanagara Palike Solid Waste Management (BBMP-SWM) Bye-laws, 2019 helped in reducing the negative externalities caused by the overconsumption of single-use plastic.” This study will be examining the effects of this law on the production and consumption of single-use plastics. Through this policy, the BBMP aims to revise the 2016 Karnataka State plastic Ban and enforce it in a stricter manner. This topic is significant as an estimated 20% of the 4000-tonne waste produced by the city consists of plastic. Plastics are not biodegradable, which increases pollution. Through this ban, the Bruhat Bengaluru Mahanagara Palike aims to reduce the external cost caused by reducing plastic consumption. Even if the plastic is marked as “recyclable” over 90% of the plastic is never actually recycled. India has been generating over 3.5 million tonnes of plastic every year. In 2017, plastic resulted in over 2.3 million premature deaths in India because of this, India made it onto the top 10 list along with China and The United States. Hence, the topic is of significant investigation. Over the years, there have been a lot of plastic bans implemented by the government. The most recent one is the Central plastic ban of 2021. Single use plastic does not biodegrade, it breaks down into smaller microplastics which continue polluting the environment.

Use of modified polycaprolactone polymer in food packaging applications: a review

Objective: Plastic production in the world is constantly increasing and plastics have been degraded in nature for many years. This situation turns into a major environmental disaster that people and living organisms will encounter. In addition, packaging films that can be applied to foods safely and extend the shelf life of foods with their functional properties are needed. Polycaprolactone (PCL) is a biodegradable polymer produced by synthetic processes and has been frequently investigated in food packaging studies in recent years. Due to its flexibility, biocompatibility and thermoplasticity, the use of PCL and its copolymers in packaging film applications is becoming widespread. Disadvantages such as low mechanical and thermal resistance can be eliminated by adding fillers, mixing with other polymers or using multi-layers. This study aims to compile recent studies on the use of PCL polymer modified by various methods as food packaging. Conclusion: In the literature, there are many interesting studies on the making composite of PCL with different methods. Nanoclays to improve mechanical and gas barrier properties; nanometals and plant materials to impart antimicrobial properties; innovative additives such as oxygen scavengers, photosynthesizing agents, antimicrobial peptides are used in the modification of PCL. In this review, it was revealed that the modifications contribute to PCL polymer in terms of stiffness and gas barrier properties and add antimicrobial and antioxidant character to the polymer.

Exploring the efficacy of ecolabels as a marketing strategy: Insights from the emerging bioplastic packaging market

AbstractThe packaging industry's significant role in plastic production and environmental pollution underscores the need for more sustainable alternatives. Bioplastics emerge as a promising solution, yet consumer understanding of this innovative material often lags, particularly in emerging markets. This study thus aims to explore effective marketing strategies for communicating bioplastic packaging to shape consumer adoption and disposal practices in such markets. Through a case study approach, we examine the role of ecolabels as a marketing tool across key sectors of the bioplastic packaging supply chain. Drawing upon the signalling theory, we identify key characteristics of effective signals, including costly signalling, visibility, clarity, fitness, consistency and credibility, which should be integrated into a broader context of ecolabels design in order to encourage consumer adoption and responsible disposal. Our study also identifies instances where noises from the environment may have little impact and where communication gaps hinder feedback loops between consumers and producers.

Stochastic dynamics mass spectrometric and Fourier transform infrared spectroscopic structural analyses of composite biodegradable plastics

<p>The (partial) replacement of synthetic polymers with bioplastics is due to increased production of conventional packaging plastics causing for severe environmental pollution with plastics waste. The bioplastics, however, represent complex mixtures of known and unknown (bio)polymers, fillers, plasticizers, stabilizers, flame retardant, pigments, antioxidants, hydrophobic polymers such as poly(lactic acid), polyethylene, polyesters, glycol, or poly(butylene succinate), and little is known of their chemical safety for both the environment and the human health. Polymerization reactions of bioplastics can produce no intentionally added chemicals to the bulk material, which could be toxic, as well. When polymers are used to food packing, then the latter chemicals could also migrate from the polymer to food. This fact compromises the safety for consumers, as well. The scarce data on chemical safety of bioplastics makes a gap in knowledge of their toxicity to humans and environment. Thus, development of exact analytical protocols for determining chemicals of bioplastics in environmental and food samples as well as packing polymers can only provide warrant for reliable conclusive evidence of their safety for both the human health and the environment. The task is compulsory according to legislation Directives valid to environmental protection, food control, and assessment of the risk to human health. The quantitative and structural determination of analytes is primary research task of analysis of polymers. The methods of mass spectrometry are fruitfully used for these purposes. Methodological development of exact analytical mass spectrometric tools for reliable structural analysis of bioplastics only guarantees their safety, efficacy, and quality to both humans and environment. This study, first, highlights innovative stochastic dynamics equations processing exactly mass spectrometric measurands and, thus, producing exact analyte quantification and 3D molecular and electronic structural analyses. There are determined synthetic polymers such as poly(ethylenglycol), poly(propylene glycol), and polyisoprene as well as biopolymers in bags for foodstuffs made from renewable cellulose and starch, and containing, in total within the 20,416–17,495 chemicals per sample of the composite biopolymers. Advantages of complementary employment in mass spectrometric methods and Fourier transform infrared spectroscopy is highlighted. The study utilizes ultra-high resolution electrospray ionization mass spectrometric and Fourier transform infrared spectroscopic data on biodegradable plastics bags for foodstuffs; high accuracy quantum chemical static methods, molecular dynamics; and chemometrics. There is achieved method performance |<em>r</em>| = 0.99981 determining poly(propylene glycol) in bag for foodstuff containing 20,416 species and using stochastic dynamics mass spectrometric formulas. The results highlight their great capability and applicability to the analytical science as well as relevance to both the fundamental research and to the industry.</p>

The time for ambitious action is now: Science-based recommendations for plastic chemicals to inform an effective global plastic treaty

The ubiquitous and global ecological footprint arising from the rapidly increasing rates of plastic production, use, and release into the environment is an important modern environmental issue. Of increasing concern are the risks associated with at least 16,000 chemicals present in plastics, some of which are known to be toxic, and which may leach out both during use and once exposed to environmental conditions, leading to environmental and human exposure. In response, the United Nations member states agreed to establish an international legally binding instrument on plastic pollution, the global plastics treaty. The resolution acknowledges that the treaty should prevent plastic pollution and its related impacts, that effective prevention requires consideration of the transboundary nature of plastic production, use and pollution, and that the full life cycle of plastics must be addressed. As a group of scientific experts and members of the Scientists' Coalition for an Effective Plastics Treaty, we concur that there are six essential “pillars” necessary to truly reduce plastic pollution and allow for chemical detoxification across the full life cycle of plastics. These include a plastic chemical reduction and simplification, safe and sustainable design of plastic chemicals, incentives for change, holistic approaches for alternatives, just transition and equitable interventions, and centering human rights. There is a critical need for scientifically informed and globally harmonized information, transparency, and traceability criteria to protect the environment and public health. The right to a clean, healthy, and sustainable environment must be upheld, and thus it is crucial that scientists, industry, and policy makers work in concert to create a future free from hazardous plastic contamination.

Deformation Estimation of Textureless Objects from a Single Image.

Deformations introduced during the production of plastic components degrade the accuracy of their 3D geometric information, a critical aspect of object inspection processes. This phenomenon is prevalent among primary plastic products from manufacturers. This work proposes a solution for the deformation estimation of textureless plastic objects using only a single RGB image. This solution encompasses a unique image dataset of five deformed parts, a novel method for generating mesh labels, sequential deformation, and a training model based on graph convolution. The proposed sequential deformation method outperforms the prevalent chamfer distance algorithm in generating precise mesh labels. The training model projects object vertices into features extracted from the input image, and then, predicts vertex location offsets based on the projected features. The predicted meshes using these offsets achieve a sub-millimeter accuracy on synthetic images and approximately 2.0 mm on real images.

Screening the release of chemicals and microplastic particles from diverse plastic consumer products into water under accelerated UV weathering conditions

Photodegradation of plastic consumer products is known to accelerate weathering and facilitate the release of chemicals and plastic particles into the aquatic environment. However, these processes are complex. In our presented pilot study, eight plastic consumer products were leached in distilled water under strong ultraviolet (UV) light simulating eight months of Central European climate and compared to their respective dark controls (DCs). The leachates and formed plastic particles were exploratorily characterized using a range of chemical analytical tools to describe degradation and leaching processes. These techniques covered (a) microplastic analysis, showing substantial liberation of plastic particles further increased under UV exposure, (b) non-targeted mass spectrometric characterization of the leachates, revealing several hundreds of chemical features with typically only minor agreement between the UV exposure and the corresponding DCs, (c) target analysis of 71 organic analytes, of which 15 could be detected in at least one sample, and (d) metal(loid) analysis, which revealed substantial release of toxic metal(loid)s further enhanced under UV exposure. A data comparison with the US-EPA’s ToxVal and ToxCast databases showed that the detected metals and organic additives might pose substantial health and environmental concerns, requiring further study and comprehensive impact assessments.

Advanced green capture of microplastics from different water matrices by surface-modified magnetic nanoparticles

The extensive production and application of plastic in recent decades has resulted in the presence of microplastics (MPs) in different water bodies. Considered as contaminants of emerging concern (CECs), MPs are accessible to a wide range of organisms and can act as vectors for the transport of other persistent organic pollutants. The existing technologies to remove microplastics from wastewaters and prevent their intrusion in nature, still present several limitations, resulting in an urgent need to develop novel, fast, cost-effective and greener alternatives. In this work, the magnetophoretic capture of MPs by their assembly with magnetic nanoparticles through either electrostatic interactions or molecular forces is investigated. For the experimental assessment, magnetic nanoparticles were synthesized by hydrothermal coprecipitation and solvothermal decomposition methods, while polyethylene (PE) microspheres were selected as model microplastic pollutants. As a noteworthy novelty, thermal decomposition and coprecipitation particles were functionalized with amino groups and sodium alginate (SA), respectively, resulting in a modification of their surface properties and enhanced electrostatic or molecular interactions with MPs. After preliminary experiments, a concentration of 1.3 g L-1 and a contact time of 20 min between magnetic nanoparticles and MPs, were selected as operating conditions to assess the influence of the functional groups on the capture performance. The influence of other variables in the process was also evaluated, including the magnetic nanoparticles synthesis method, the pH of the medium, varied in the range 4–8, and the water constituents that may be present in water bodies. Results demonstrated that the presence of different types of polar groups on the surface of the magnetic nanoparticles make them interact towards MPs through electrostatic attraction or molecular forces, considerably enhancing the capture performance of bare magnetic nanoparticles. This work represents a step forward in the development of new and reliable techniques for the environmentally friendly capture of microplastics from polluted waters.

Transformation of D-xylose into furfuryl alcohol via an efficient chemobiological approach in a benign deep eutectic solvent lactic acid:betaine-water reaction system

Biobased furfuryl alcohol (FOL) was a common building block for the production of resins, lubricants, plasticizers, organic compounds and value-added intermediates. For the effectual efficient production of FOL, a combination of chemocatalytic and biocatalytic approach was built for the transformation of D-xylose to FOL in a deep eutectic solvent (DES) lactic acid:betaine-H2O (LA:Bet-H2O) system. The furfural (FAL) yield of LA:Bet-H2O (10:90, vol/vol) for 30 min at 180 °C reached 81.6 % using D-xylose (150 g/L) as substrate in a high-pressure reactor. Using glucose as co-substrate, E. coli HMFOMUT whole cell could transform the formed FAL (125 mM) into FOL (96.8 % yield) in a conical flask at 37 °C and pH 7.0 in this LA:Bet-H2O (5:95, vol/vol) medium. In 50 mL LA:Bet-H2O, HMFOMUT cells effectually convert D-xylose-derived FAL to FOL, and 0.75 g of D-xylose formed FOL (0.384 g, 78.2 % yield) and furoic acid (FA) (0.019 g, 3.4 % yield). In the present study, a one-pot tandem method was used to effectually catalyze the synthesis of FOL from D-xylose using an effectual combination of chemocatalysis with LA:Bet and biocatalysis with E. coli HMFOMUT in a reactor. It affords a new idea for the effectual use of biomass resources to synthesize high value-added compounds, and also renders a mild, green, environmentally friendly and sustainable strategy for the manufacturing of bio-based platform derivatives.

Determination of Residual Stresses in 3D-Printed Polymer Parts.

This paper presents the results of an investigation of the possibility of the reliable determination of the residual stress-strain state in polymers and composites using a combination of bridge curvature, optical scanning, and finite element methods. A three-factor experiment was conducted to determine the strength of printed PLA plastic products. The effect of the residual stresses on the strength of the printed products was evaluated. By comparing the values of the same strength stresses, a relationship between the nature of the stresses and the strength of the samples was found. A tendency of the negative influence of tensile stresses and the opposite strengthening effect of compressive stresses was obvious, so at the same values of tensile strength, the value of residual stress of 42.9 MPa is lower than that of the fibre compression at the value of 88.9 MPa. The proposed new methods of the residual stress determination allow obtaining a complete picture of the stressed state of the material in the investigated areas of the products. This may be necessary in confirming the calculated models of the residual stress-strain state, clarifying the strength criteria and assessing the quality of the selected technological modes of manufacturing the products.

Intelligent Inspection Method and System of Plastic Gear Surface Defects Based on Adaptive Sample Weighting Deep Learning Model.

After injection molding, plastic gears often exhibit surface defects, including those on end faces and tooth surfaces. These defects encompass a wide range of types and possess complex characteristics, which pose challenges for inspection. Current visual inspection systems for plastic gears suffer from limitations such as single-category defect inspection and low accuracy. There is an urgent industry need for a comprehensive and accurate method and system for inspecting defects on plastic gears, with improved inspection capability and higher accuracy. This paper presents an intelligent inspection algorithm network for plastic gear defects (PGD-net), which effectively captures subtle defect features at arbitrary locations on the surface compared to other models. An adaptive sample weighting method is proposed and integrated into an improved Focal-IoU loss function to address the issue of low inspection accuracy caused by imbalanced defect dataset distributions, thus enhancing the regression accuracy for difficult defect categories. CoordConv layers are incorporated into each inspection head to improve the model's generalization capability. Furthermore, a dataset of plastic gear surface defects comprising 16 types of defects is constructed, and our algorithm is trained and tested on this dataset. The PGD-net achieves a comprehensive mean average precision (mAP) value of 95.6% for the 16 defect types. Additionally, an online inspection system is developed based on the PGD-net algorithm, which can be integrated with plastic gear production lines to achieve online full inspection and automatic sorting of plastic gear defects. The entire system has been successfully applied in plastic gear production lines, conducting daily inspections of over 60,000 gears.

Photochemical Aerobic Upcycling of Polystyrene Plastics via Synergistic Indirect HAT Catalysis.

Plastic pollution constitutes an evergrowing urgent environmental problem, since overaccumulation of plastic waste, arising from the immense increase of the production of disposable plastic products, overcame planet's capacity to properly handle them. Chemical upcycling of polystyrene constitutes a convenient method for the conversion of plastic waste into high-added value chemicals, suggesting an attractive perspective in dealing with the environmental crisis. We demonstrate herein a novel, easy-to-perform organocatalytic photoinduced aerobic protocol, which proceeds via synergistic indirect hydrogen atom transfer (HAT) catalysis under LED 390 nm Kessil lamps as the irradiation source. The developed method employs a BrCH2CN-thioxanthone photocatalytic system and was successfully applied to a variety of everyday-life plastic products, leading to the isolation of benzoic acid after simple base-acid work up in yields varying from 23-49 %, while a large-scale experiment was successfully performed, suggesting that the photocatalytic step is susceptible to industrial application.