Plastic Products Research Articles

In search of poly-3-hydroxybutyrate (PHB): A comprehensive review unveiling applications and progress in fostering a sustainable bio-circular economy

The escalating demand for economical and durable materials has propelled plastics into an indispensable facet of daily human life, dominating commercial and industrial sectors. The global plastic production of 1.1 billion tons by 2050 exacerbates concerns. The COVID-19 pandemic has further intensified the issue, reaching an alarming 0.3–0.4 billion tons annually. Urgent action is imperative to curtail the drastic environmental impact. Various strategies, particularly microbial involvement in plastic production and degradation, must be implemented to address this. Poly-3-Hydroxybutyrate (PHB) microbial polyesters present a promising alternative to conventional plastics because of their biodegradable nature, thus offering a sustainable solution to plastic pollution. PHBs are employed in divergent industries, including agriculture, medicine, nanotechnology, food, and tissue engineering. This comprehensive review addresses the gap in the literature by encompassing a wide range of topics related to PHBs, their associated enzymes, metabolic pathways, and applications. It also provides an in-depth analysis, highlighting the significance of diverse microbial communities in both the synthesis and degradation of biopolymers. Strategies for augmenting PHA production and leveraging waste products for circular economy initiatives are also discussed, emphasizing the need for innovative solutions to address the global plastic crisis.Top of Form This review highlights two critical strategies for tackling plastic pollution: introducing alternative materials like bioplastics and leveraging biological recycling with microbial assistance. Adopting bio-based circular economy strategies, implementing comprehensive 6 R waste management practices, strengthening plastic pollution regulations, and raising social awareness can significantly improve eco-friendly plastic waste management, diminish pollution, and enhance socio-economic conditions, thus benefiting economies worldwide.

Advancements in Synthetic Biology for Enhancing Cyanobacterial Capabilities in Sustainable Plastic Production: A Green Horizon Perspective

This comprehensive review investigates the potential of cyanobacteria, particularly nitrogen-fixing strains, in addressing global challenges pertaining to plastic pollution and carbon emissions. By analyzing the distinctive characteristics of cyanobacteria, including their minimal growth requirements, high photosynthetic efficiency, and rapid growth rates, this study elucidates their crucial role in transforming carbon sequestration, biofuel generation, and biodegradable plastic production. The investigation emphasizes cyanobacteria’s efficiency in photosynthesis, positioning them as optimal candidates for cost-effective bioplastic production with minimized land usage. Furthermore, the study explores their unconventional yet promising utilization in biodiesel production, mitigating environmental concerns such as sulfur emissions and the presence of aromatic hydrocarbons. The resulting biodiesel exhibits significant combustion potential, establishing cyanobacteria as a viable option for sustainable biofuel production. Through a comprehensive assessment of both achievements and challenges encountered during the commercialization process, this review offers valuable insights into the diverse contributions of cyanobacteria. Its objective is to provide guidance to researchers, policymakers, and industries interested in harnessing bio-inspired approaches for structural and sustainable applications, thereby advancing global efforts towards environmentally conscious plastic and biofuel production.

High-throughput transcriptomics toxicity assessment of eleven data-poor bisphenol A alternatives

Bisphenol A (BPA), a widely used chemical in the production of plastics and epoxy resins, has garnered significant attention due to its association with adverse health effects, particularly its endocrine-disrupting properties. Regulatory measures aimed at reducing human exposure to BPA have led to a proliferation of alternative chemicals used in various consumer and industrial products. While these alternatives serve to reduce BPA exposure, concerns have arisen regarding their safety and potential toxicity as regrettable substitutes. Previous efforts have demonstrated that in vitro high-throughput transcriptomics (HTTr) studies can be used to assess the endocrine-disrupting potential of BPA alternatives, and this strategy produces transcriptomic points-of-departure (tPODs) that are protective of human health when compared to the PODs from traditional rodent studies. In this study, we used in vitro HTTr to assess the potential for toxicity of eleven data-poor legacy chemicals sharing structural similarities to BPA. Human breast cancer MCF-7 cells were exposed to BPA and 11 alternatives at concentrations ranging from 0.1 to 25 μM to assess toxicity. Analysis of global transcriptomic changes and a previously characterized estrogen receptor alpha (ERα) transcriptomic biomarker signature revealed that 9 of 11 chemicals altered gene expression relative to controls. One of the chemicals (2,4′-Bisphenol A) activated the ERα biomarker at the same concentration as BPA (i.e., 4,4′-BPA) but was deemed to be more potent as it induced global transcriptomic changes at lower concentrations. These results address data gaps in support of ongoing screening assessments to identify BPA alternatives with hazard potential and help to identify potential candidates that may serve as safer alternatives.

Encapsulation and release of tetrabromobisphenol A in microplastics: Trade-off in their individual toxicity to Xenopus tropicalis tadpoles

The toxicity of microplastics (MPs) to aquatic animals is closely related to the presence and release kinetics of contained additives, as most plastic products contain various additives. However, the relationship between the occurrence and release of additives from MPs, and their individual or combined toxicity remains unclear. In this study, the nanoscale distribution and release of tetrabromobisphenol A (TBBPA, a common flame retardant with endocrine-disrupting effect) in polystyrene (PS) MPs, and the long-term (60 days) toxicity of TBBPA and MPs containing TBBPA (at doses of 0 %, 1 %, 10 %, w/w) to Xenopus tropicalis tadpoles were investigated. Exposure to 10 μg/L TBBPA alone was the most toxics, while the encapsulation of TBBPA in MPs significantly delayed its lethal toxicity to tadpoles by inhibiting the rapid and extensive release of TBBPA. PS MPs alone and MPs containing 10 % TBBPA exhibited delayed survival toxicity compared to TBBPA alone, whereas PS MPs containing 1 % TBBPA did not show this effect but inhibited growth. These findings suggest that chronic toxicity assessments should be based on long-term (months or even years) exposure experiments due to the encapsulation-controlled slow release of toxic additives.

Methodology Approach for Microplastics Isolation from Samples Containing Sucrose.

The growing production and use of plastics significantly contribute to microplastics (MPs) contamination in the environment. Humans are exposed to MPs primarily through the gastrointestinal route, as these particles are present in beverages and food, e.g., sugar. Effective isolation and identification of MPs from food is essential for their elimination. This study aimed to evaluate factors influencing the isolation of MPs from sucrose solutions to determine optimal conditions for the process. Polyethylene particles were used to test separation methods involving chemical digestion with acids and filtration through membrane filters made of nylon, mixed cellulose ester, and cellulose acetate with pore sizes of 0.8 and 10 µm. The effects of temperature and acid type and its concentration on plastic particles were examined using scanning electron microscopy and µ-Raman spectroscopy. The results indicate that increased temperature reduces solution viscosity and sucrose adherence to MPs' particles, while higher acid concentrations accelerate sucrose hydrolysis. The optimal conditions for MPs' isolation were found to be 5% HCl at 70 °C for 5 min, followed by filtration using an efficient membrane system. These conditions ensure a high recovery and fast filtration without altering MPs' surface properties, providing a reliable basis for further analysis of MPs in food.

Sustainable Plastic Waste Management in Thanjavur District: An Evaluation Using Fuzzy AHP and Neutrosophic TOPSIS

Introduction: The amount of plastic garbage has increased in tandem with the steady growth in the use of plastic products worldwide. Since plastics are lightweight, inexpensive, and durable, they are highly appreciated in a variety of industries, including electronics, building, packaging, healthcare, and agriculture). Plastic's cost, adaptability, resistance to corrosion, durability, and ease of production all contribute to its rising demand.With changes to the Plastic Waste Management Rules, India has made managing single-use plastics a top priority. Objectives: The research provides an extensive examination of the methods used to manage plastic garbage in Thanjavur's rural villages. Examining household behaviors and waste production trends, it reveals a wide range of plastic kinds, including polystyrene (PS), polypropylene (PP), high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polyethylene terephthalate (PET). Methods: The research uses a Multi-Criteria Decision Making (MCDM) approach that combines the Neutrosophic Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) for alternative ranking with the Fuzzy Analytic Hierarchy Process (FAHP) for criteria weighting. Although it uses fuzzy logic to address ambiguity and uncertainty in decision-making processes, the Fuzzy AHP approach is applied in a manner similar to that of AHP. Results: Egestas diam in arcu cursus euismod quis viverra nibh. Convallis aenean et tortor at risus viverra. Sit amet justo donec enim diam. Sem et tortor consequat id. Purus gravida quis blandit turpis. Consectetur adipiscing elit duis tristique sollicitudin nibh sit amet commodo. Eget duis at tellus at urna condimentum mattis pellentesque. Auctor elit sed vulputate mi sit amet. Conclusions: This study determines that, among the available options, Polyethylene Terephthalate (PET) is the best option by applying the fuzzy analytic hierarchy process (Fuzzy AHP) to balance these criteria. PET exhibits potential because of its economic and environmental advantages, but its effective application necessitates customized strategies that take into account the infrastructure constraints and socioeconomic characteristics of the local area. Programs for raising community knowledge and participation are crucial in promoting sustainable waste management techniques, as the study emphasizes.

Evaluation of Bisphenol S (BPS) toxicity on the reproductive system of Channa striatus: Insights for environmental risk assessment

Aquatic ecosystems face significant exposure to endocrine-disrupting chemicals (EDCs), which can mimic, block, or alter the synthesis of endogenous hormones. Bisphenol A (BPA), a widely known EDC, has been phased out from consumer products due to concerns about its potential impacts on human health. In its place, bisphenol S (BPS), an organic compound, has been increasingly used in the production of polycarbonate plastics, epoxy resins, thermal receipt papers, and currency. Vitellogenin (Vtg), a yolk precursor protein synthesized in the liver and present in oviparous fish, particularly males, serves as a pertinent biomarker for studying the effects of estrogenic EDCs on fish. This study aimed to assess the impact of BPS on reproductive parameters and hepatic vitellogenin expression in Channa striatus. The LC50 of BPS was determined to be 128.8 mg/L. Experimental groups included control and BPS-exposed fish, with sub-lethal concentrations of BPS (1 mg/L, 4 mg/L, and 12 mg/L) administered and effects monitored at seven- and twenty-one-day intervals. Significant decreases in gonadosomatic index (GSI), ova diameter, and fecundity were observed in BPS-exposed Channa striatus. Hepatic Vtg mRNA expression was downregulated in female and upregulated in male following BPS exposure. Serum hormone analysis confirmed the estrogenic activity of BPS. These findings underscore BPS's ability as an endocrine disruptor to interfere with hormone synthesis and disrupt spermatogenesis and oogenesis processes in Channa striatus. This research contributes to understanding the endocrine-disrupting effects of BPS on aquatic organisms, highlighting potential ecological implications and the need for continued monitoring and regulatory considerations.

Cobalt nanoparticles attenuate microplastic-induced vascular endothelial injury via Nrf2 pathway activation

The widespread utilization of plastic and cobalt alloy products in industries and medicine has led to the increased presence of their degradation byproducts, microplastics (MPs), and cobalt nanoparticles (Co NPs), in the environment and organisms. While these particles can circulate throughout the body via the circulatory system, their specific adverse effects and mechanisms on the vascular system remain unclear. Employing scanning electron microscope (SEM) analysis and other methodologies, we demonstrate the potential adsorption and aggregation phenomena between MPs and Co NPs. In vitro experiments illustrate that ingestion of either MPs or Co NPs compromises vascular endothelial cell function and induces the generation of reactive oxygen species (ROS). Notably, this effect is markedly attenuated when a combination of MPs and Co NPs is administered compared to MPs alone. Additionally, zebrafish experiments validate our in vitro findings. Mechanistic studies have demonstrated that both MPs and Co NPs induce aberrant Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. Intriguingly, a weaker activation level is observed when these agents are administered in combination compared to when they are administered individually. Our study provides novel insights into the interaction between MPs and Co NPs and their detrimental effects on vascular endothelial cells.

Accelerating microplastic contamination in 210Pb dated sediment cores from an urbanized coastal lagoon (NW Mexico) since the 1990s

The ubiquity of microplastics (MP) across all ecosystems raises concerns about their potential harm to the environment and living organisms. Sediments are a MP sink, reflecting long-term accumulation and historical anthropogenic impacts. Three 210Pb-dated sediment cores were used to understand the temporal variations of MP abundances (particles kg−1) and fluxes (particles m−2 year−1) within the past century in Estero de Urías Lagoon, an urbanized coastal lagoon in the Mexican Pacific. MP particles, extracted from sediments by density separation (saturated NaCl solution) were counted using a stereomicroscope, under visible and ultraviolet light on Nile red (NR) stained filters. The polymer composition was determined in ∼10 % of the suspected MP particles using Fourier Transform Infrared spectrometry. Fibers (66 to 89 % of the total particles) predominated over fragments (11 to 34 %). Before 1950, no MP particles were detected. Polyethylene terephthalate (PET) was the prevalent synthetic polymer (up to 50 % of the particles), while semisynthetic cellulosic fibers were predominant, underscoring the broader scope of anthropogenic contamination. Suspected MP abundances (NR stained filters) were highest in the core collected at the innermost area, which was attributed to the lagoon's hydrodynamics, since current velocities decrease from the proximal to the distal area to the sea. From the regression between MP fluxes and time elapsed since sediments deposited, the cores showed consistent accelerated increases of MP burial since mid-20th century, most likely because of the increasing availability of plastic products and population growth, with the consequent increment in plastic waste and wastewater releases. Our findings emphasize the growing MP pollution challenges at EUL, which may directly impact subsistence fishing and shrimp aquaculture activities, threatening local livelihoods and food sources; and also highlight the need for improved waste management and pollution control strategies in rapidly industrializing regions, to protect both aquatic ecosystems and human populations dependent on fishing products.

Catalyst free PET and PEF polyesters using a new traceless oxalate chain extender.

Plastic material performance is strongly correlated to the polymer's molecular weight. Obtaining a sufficiently high molecular weight is therefore a key goal of polymerization processes. The most important polyester polyethylene terephthalate (PET) and the new polyethylene furanoate (PEF) require metal catalysts and time-consuming production processes to reach sufficiently high molecular weights. Metal catalysts, which are typically antimony or tin for polyesters, end up in the plastic products which may result in sustainability and ecological challenges. When the less reactive comonomer isosorbide is introduced to produce (partly) biobased materials with enhanced thermal properties, such as polyethylene-co-isosorbide furanoate (PEIF), reaching high enough molecular weight becomes even more challenging. This study presents an easily implementable approach to produce high molecular weight PET and PEF polyesters and their isosorbide copolyesters PEIT and PEIF by coupling lower molecular weight polymer chains by the reactive diguaiacyl oxalate (DGO) chain extender. DGO is so reactive, that the use of metal catalysts can be completely avoided and it helps avoiding an extra solid-state polymerization step. In addition, DGO distinguishes itself from typical chain extenders by its ability to be completely removed from the resulting polymer, thereby avoiding the inherent drawbacks associated with typical chain extenders.

Impact of diatomit on the transport behavior of unmodified and carboxyl-modified nanoplastics in saturated porous media

Due to the extensive use of plastic products and unreasonable disposal, nanoplastics contamination has become one of the important environmental problems that mankind must face. The composition and structure of porous media can determine the complexity and diversity of the transport behavior of nanoplastics. In this study, the influence of diatomite (DIA) on the nanoplastics transport in porous media is investigated by column experiments combined with XDLVO interaction energy and transport model. Results suggest that the recovery rates of unmodified polystyrene nanoparticles (PSNPs) and carboxyl-modified polystyrene nanoparticles (PSNPs-COOH) in the porous media containing DIA decreases compared with that in the pure quartz sand (QS), and the BTCs showed a “blocking” pattern. The presence of DIA inhibits the transport of both PSNPs and PSNPs-COOH, but the inhibition is not significant. This may be because the presence of DIA provides more favorable deposition sites for PSNPs and PSNPs-COOH to some extent. However, since DIA itself carries a certain negative charge, this can only play a role in compressing the double electric layer for PSNPs and PSNPs-COOH with the same negative charge, and cannot destabilize them. The migration capacity of PSNPs and PSNPs-COOH is strongest in the DIA-QS porous media at pH = 7, and is weak at pH = 9 and pH = 5. The inhibition of migration at pH = 9 can be attributed to the dissolution of the DIA surface under alkaline conditions and the formation of pore and defect structures, which provide more deposition sites for PSNPs and PSNPs-COOH. The presence of humic acid (HA) leads to an increase in the mobility of PSNPs and PSNPs-COOH, and the mobility is enhanced with HA concentration. The mobility of PSNPs and PSNPs-COOH in DIA-QS decreases with ionic valence and ionic strength, and PSNPs-COOH is more significantly inhibited compared to PSNPs.

Study of Injection Molding Process to Improve Geometrical Quality of Thick-Walled Polycarbonate Optical Lenses by Reducing Sink Marks.

This study investigates the challenges and potential of conventional injection molding for producing thick-walled optical components. The research primarily focuses on optimizing process parameters and mold design to enhance product quality. The methods include software simulations and experimental validation using polycarbonate test samples (optical lenses). Significant parameters such as melt temperature, mold temperature, injection pressure, and packing pressure were varied to assess their impact on geometric accuracy and visual properties. The results show that lower melt temperatures and higher mold temperatures significantly reduce the occurrence of dimensional defects. Additionally, the design of the gate system was found to be crucial in minimizing defects and ensuring uniform material flow. Effective packing pressure was essential in reducing volumetric shrinkage and sink marks. Furthermore, we monitored the deviation between the predicted and actual defects relative to the thickness of the sample wall. After optimization, the occurrence of obvious defects was eliminated across all sample thicknesses (lenses), and the impact of the critical defect, the sink mark on the planar side of the lens, was minimized. These findings demonstrate the substantial potential of conventional injection molding to produce high-quality thick-walled parts when these parameters are precisely controlled. This study provides valuable insights for the efficient design and manufacturing of optical components, addressing the growing demand for high-performance thick-walled plastic products.

Adsorption behavior of heavy metals onto microplastics derived from conventional and biodegradable commercial plastic products

This study extensively explored the adsorption behavior of heavy metals (Pb+2, Ni+2, Cu+2, Zn+2, and Cd+2) onto microplastics (MPs). The particle sizes of MPs ranged from 0.149 to 0.25 mm. The microplastics were generated from commercial products manufactured from both conventional (polyethylene (PE) bottle, polystyrene (PS) spoon, and polyethylene terephthalate (PET) egg carton) and biodegradable (polylactic acid (PLA) spoon, and polylactic acid (PLA) egg carton) plastics. The study also considered the influence of solution pH on the adsorption capacity of heavy metals. Regarding the adsorption potential for Cu+2, the ranking was as follows: PLA-egg (1408 μg·g−1) > PLA-spoon (735 μg·g−1) > PE-bottle (315 μg·g−1) > PET-egg (283 μg·g−1) > PS-spoon (237 μg·g−1). PLA MPs showed the highest adsorption capacity due to the lower thermal stability and higher presence of surface oxygen functional groups. Moreover, the adsorption capacities of the five metals onto PLA-spoon and PLA-egg decreased in the following order: Pb (1785 μg·g−1) > Zn (1267 μg·g−1) > Cd (748 μg·g−1) > Cu (735 μg·g−1) > Ni (722 μg·g−1), and Pb (1520 μg·g−1) > Ni (1412 μg·g−1) > Cu (1408 μg·g−1) > Zn (1118 μg·g−1) > Cd (423 μg·g−1), respectively. The SEM-EDS, FTIR and XPS results demonstrated that surface oxygen-containing functional groups play an important role during the adsorption process. This study extended its analysis to quantify the metal content of the post-adsorption MPs, revealing uneven adsorption of heavy metals onto the MPs. This implies that the diversity of commercial plastic products may result in significant variations in their ability to adsorb heavy metals, underscoring the importance of effectively managing discarded commercial plastic products.

Protein Corona-Directed Cellular Recognition and Uptake of Polyethylene Nanoplastics by Macrophages.

The widespread use of plastic products in daily life has raised concerns about the health hazards associated with nanoplastics (NPs). When exposed, NPs are likely to infiltrate the bloodstream, interact with plasma proteins, and trigger macrophage recognition and clearance. In this study, we focused on establishing a correlation between the unique protein coronal signatures of high-density (HDPE) and low-density (LDPE) polyethylene (PE) NPs with their ultimate impact on macrophage recognition and cytotoxicity. We observed that low-density and high-density lipoprotein receptors (LDLR and SR-B1), facilitated by apolipoproteins, played an essential role in PE-NP recognition. Consequently, PE-NPs activated the caspase-3/GSDME pathway and ultimately led to pyroptosis. Advanced imaging techniques, including label-free scattered light confocal imaging and cryo-soft X-ray transmission microscopy with 3D-tomographic reconstruction (nano-CT), provided powerful insights into visualizing NPs-cell interactions. These findings underscore the potential risks of NPs to macrophages and introduce analytical methods for studying the behavior of NPs in biological systems.

Fabricating High Strength Bio-Based Dynamic Networks from Epoxidized Soybean Oil and Poly(Butylene Adipate-co-Terephthalate).

Amid the rapid development of modern society, the widespread use of plastic products has led to significant environmental issues, including the accumulation of non-degradable waste and extensive consumption of non-renewable resources. Developing healable, recyclable, bio-based materials from abundant renewable resources using diverse dynamic interactions attracts increasing global attention. However, achieving a good balance between the self-healing capacity and mechanical performance, such as strength and toughness, remains challenging. In our study, we address this challenge by developing a new type of dynamic network from epoxidized soybean oil (ESO) and poly(butylene adipate-co-terephthalate) (PBAT) with good strength and toughness. For the synthetic strategy, a thiol-epoxy click reaction was conducted to functionalize ESO with thiol and hydroxyl groups. Subsequently, a curing reaction with isocyanates generated dynamic thiourethane and urethane bonds with different bonding energies in the dynamic networks to reach a trade-off between dynamic features and mechanical properties; amongst these, the thiourethane bonds with a lower bonding energy provide good dynamic features, while the urethane bonds with a higher bonding energy ensure good mechanical properties. The incorporation of flexible PBAT segments to form the rational multi-phase structure with crystalline domains further enhanced the products. A typical sample, OTSO100-PBAT100, exhibited a tensile strength of 33.2 MPa and an elongation at break of 1238%, demonstrating good healing capacity and desirable mechanical performance. This study provides a promising solution to contemporary environmental and energy challenges by developing materials that combine mechanical and repair properties. It addresses the specific gap of achieving a trade-off between tensile strength and elongation at break in bio-based self-healing materials, promising a wide range of applications.

Assessment of phthalate esters migration in plastic products marketed in Turkey for food use

Assessment of phthalate esters migration in plastic products marketed in Turkey for food use

Comparative analysis of additive decomposition using one-dimensional and two–dimensional gas chromatography: Part II - Irgafos 168 and zinc stearate

Plastic production has experienced a significant increase in the last sixty years due to its cost-efficiency and adaptable characteristics, leading to the extensive use of additives to improve its performance and longevity. Due to the high demand for plastic, plastic waste production has increased, contaminating the environment and living beings by leaching additives, among other substances. Pyrolysis stands out among recycling techniques because it can handle mixed polymer waste feedstock. However, understanding the pyrolyzates distribution of additives is fundamental to assessing pyrolysis process of plastic waste. This study investigated the pyrolysis product distributions of two commonly used antioxidants, namely, Irgafos 168 and zinc stearate (ZnSt), using one-dimensional gas chromatography equipped with a quadruple mass spectrometer (GC–MS) and two-dimensional gas chromatography coupled to flame ionization detector and time–of–flight mass spectrometer (GC×GC–FID/TOF–MS). While GC separation technique provided limited information on product distribution, GC×GC offered enhanced resolution and identification of the decomposition products. In the pyrolysis of Irgafos 168 at 550 °C, GC identified 18 products, while GC×GC identified 198 products, representing an increase of approximately 11-fold. Similarly, for ZnSt, GC identified 67 products, while GC×GC identified 434 products, representing a 6-fold increase. GC×GC identified decomposition products from 15 different chemical classes for Irgafos 168 and 16 chemical classes for ZnSt, compared to 4 and 11 chemical classes identified by GC, respectively. Phenols and their derivatives were the major chemical class in the decomposition products of Irgafos 168 with a yield of 9.51 wt.%. In contrast, olefinic products were the dominant ones for ZnSt, with a yield of 9.73 wt.%. The major decomposition product of Irgafos 168 and ZnSt was 2‑tert‑butyl‑methylphenol (C11H16O) and C6 olefin (C6H12) with yields of 3.88 wt.%, and 1.13 wt.%, respectively. Utilizing the GC×GC separation method improved the ability to identify decomposition products, which can ultimately lead to a better understanding of antioxidant degradation that occurs during the pyrolysis process. GC×GC also provided thorough characterization of minor and co-eluted products along with major antioxidant degradation products. Additionally, the decomposition product distribution of Irgafos 168 and ZnSt was also compared with the primary antioxidants, Irganox 1010, Irganox 1076, and BHT, studied in part 1. The analysis indicated that the olefinic chemical class was the predominant one in Irganox 1010, Irganox 1076, and ZnSt, while ketones were the major chemical class in the decomposition of BHT and phenolics had the highest yield in Irgafos 168.

Accelerated Development and Optimization of Adiponitrile Production via Kolbe Electrolysis of Biomass-Derived Precursors

Environmental and societal pressures are demanding a transition from fossil-based resources to renewable and sustainable feedstocks for the production of materials. In this context, biomass streams emerge as scalable candidates for creating sustainable chemicals. Electrocatalytic transformation of biomass can facilitate the production of chemicals under mild conditions and can be easily integrated with renewable energy sources. These transformations could lead to the production of sustainable monomers and polymers from biomass, significantly enhancing the sustainability of plastics production. Amongst a large number of plastics manufactured by the chemical industry, Nylon 6,6 is one of the most important fossil-derived polymers for the production of high-performance textiles and structural materials. Central to Nylon 6,6 production is adiponitrile (ADN), predominantly synthesized via energy-intensive thermochemical processes. An alternative route, electrochemical hydrodimerization of acrylonitrile (AN), although successful, still depends on fossil feedstocks. A promising sustainable source for ADN is renewable glutamic acid, derived from hydrolysis of waste proteins.1,2 This process involves transforming glutamic acid to 3-cyanopropanoic acid (CPA) and then to ADN through Kolbe electrolysis, a reaction with a historical background and multiple pathways. Our study utilizes an electrochemical reaction engineering approach to examine the Kolbe electrolysis of CPA to ADN and AN, focusing on a hierarchical research methodology. This approach allowed us to simultaneously accelerate the exploration of numerous reaction parameters while also conducting detailed studies under optimal conditions. This method has enabled us to gain deeper insights into the factors controlling reaction selectivity. We discovered that platinum electrodes favor ADN formation, with selectivity increasing at higher current densities. Optimal CPA concentrations, the presence of larger alkali cations, solvent composition, and controlled pH levels significantly influence ADN production, reducing side reactions such as the oxygen evolution reaction (OER). When using graphite electrodes, an increase in AN production was observed, with the solvent composition playing a crucial role in determining the rate of ADN formation. Our investigation has led to a deeper understanding of the electrochemical conversion of CPA to ADN, revealing key parameters that influence reaction selectivity and rate. The insights obtained from this study are not only pivotal for the specific case of ADN production but also have broader implications for a range of electrochemical decarboxylation reactions. The hierarchical research approach employed here demonstrates its potential for speeding the development of sustainable electrochemical processes. Our insights and methodology used for the electrosynthesis of ADN from biomass-derived feedstocks can be deployed to the deployed to the development of other biomass transformations advancing our ability to produce essential chemicals sustainably.

Little change in plastic loads in South Atlantic seabirds since the 1980s

Despite growing concern about the large amounts of waste plastic in marine ecosystems, evidence of an increase in the amount of floating plastic at sea has been mixed. Both at-sea surveys and ingested plastic loads in seabirds show inconsistent evidence of significant increases in the amount of plastic since the 1980s. We use 3727 brown skua Catharacta antarctica regurgitations, each containing the remains of a single seabird, to monitor changes in plastic loads in four seabird taxa breeding at Inaccessible Island, Tristan da Cunha in nine years from 1987 to 2018. Frequency of occurrence in plastic ingestion and types were compared across four near-decadal time periods (1987–1989; 1999–2004; 2009–2014 and 2018) while loads were compared among years. The number and proportions of industrial pellets among ingested plastic decreased consistently over the study period in all four taxa, suggesting that industry initiatives to reduce pellet leakage have reduced the numbers of pellets at sea. Despite global plastic production increasing more than four-fold over the study period, there was no consistent increase in the total amount of ingested plastic in any species. Plastic loads in great shearwaters Ardenna gravis, which spend the austral winter in the North Atlantic Ocean, increased in 2018, but the proportion of shearwaters containing plastic decreased. We conclude that the density of plastic floating at sea has not increased in line with global production over the last 30 years.

Fused deposition modeling of polyethylene (PE): Printability assessment for low-density polyethylene and polystyrene blends

There is a global emphasis on recycling and reuse of plastic waste. Despite constituting over one-third of the world's annual plastic production, only 10 % of polyethylene is recycled. This study explores the use of fused deposition modeling (FDM) to enable the recycling of industrial waste of low-density polyethylene (LDPE) blended with expanded polystyrene (EPS). Two LDPE/EPS ratios (50/50 and 70/30) were investigated, and two types of styrene-ethylene-butylene-styrene (SEBS) rubber were incorporated as compatibilizers. The mechanical, rheological, thermal, and morphological properties of these blends were analyzed to assess their printability. Results indicate that the use of SEBS enhances the mechanical properties, thermal stability, and morphological uniformity of the blends. Particularly, malleated SEBS exhibited superior compatibilizing ability, fostering strong interactions at the LDPE/EPS interface. The best blend, based on printability assessments, was the 50/50 LDPE/EPS ratio with a 5 wt% malleated SEBS. Consequently, this blend was extruded into feedstock filaments, and it was successfully printed via FDM. The proposed blends are anticipated to perform effectively in various applications and serve as a foundation for future development of wear-resistant materials. The outcomes of this study present a novel approach for upcycling LDPE waste while promoting sustainable FDM practices.