Search Results (651)

Conductive polymer composites with a segregated structure are a promising route to obtaining electrically active materials at low filler loadings. In this work, aminated graphene (AmG) was used as a functional conductive filler for the fabrication of composites with a segregated structure based on polyvinyl chloride (PVC) and poly(vinylidene fluoride-co-tetrafluoroethylene) (P(VDF-TFE)). AmG was comprehensively characterized by electron microscopy, core-level and near-edge spectroscopy, optical spectroscopy, and electrical measurements. The synthesized AmG contained 14.34 at.% nitrogen, with amines accounting for 81.44% of the nitrogen-related spectral intensity, corresponding to an amine concentration of 11.78 at.%. AmG also exhibited a restored π-conjugated network, intrinsic conductivity of 20–33 S/cm, and a crumpled-flake morphology favorable for interfacial contact with polymer particles. At a filler loading of only 1 wt.%, the segregated composites reached electrical conductivity up to 1.3–1.4 × 10⁻⁴ S/cm, exceeding those of the unfilled polymers by seven orders of magnitude. At 11 GHz, the AmG-filled P(VDF-TFE) composite showed 15.1 dB attenuation for a theoretical thickness of 30 mm, transmitting no more than 3% of the incident radiation. These results identify AmG as a functional conductive filler for segregated electrically conductive polymer composites and demonstrate that the combination of amine-containing surface chemistry, restored electrical conductivity, and crumpled morphology enables conductive interparticle network formation in PVC- and P(VDF-TFE)-based composites at only 1 wt.% filler loading. Full article

The expansion of climate monitoring networks has generated an increasing accumulation of end-of-life meteorological sensors, creating a specialized stream of waste electrical and electronic equipment (WEEE) that remains largely unaddressed in developing countries. This study presents a material characterization and sustainable management framework for obsolete meteorological sensors installed in automatic weather stations in Ecuador. A hybrid methodological approach was applied, combining field inventory of 16 stations, gravimetric measurements, and analysis of manufacturer technical specifications to estimate material composition and recovery potential. Results show that 65–90% of the total sensor mass consists of recyclable materials, including aluminum, stainless steel, copper, glass, and engineering polymers. A smaller fraction contains components requiring controlled management due to the potential presence of hazardous additives, such as PVC (polyvinyl chloride) elements and electronic microdevices. Based on these findings, a multi-phase management protocol is proposed, incorporating selective disassembly, material segregation, traceability mechanisms, and processing under extended producer responsibility principles. The framework supports circular economy strategies and offers a replicable model for improving sustainability in climate monitoring infrastructure and specialized WEEE management in low- and middle-income countries. Full article

The current approach to coastal oyster reef restoration currently relies on conventional plastics, raising concerns about plastic pollution. Therefore, developing biodegradable alternatives, such as nano-montmorillonite-modified polylactic acid materials (PLA), has become a priority. This study compared oyster recruitment on PLA substrates with that on four conventional plastic substrates (polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET) and polyvinylidene chloride (PVDC)) through field experiments, examining how PLA substrate thickness and surface roughness influence oyster recruitment. Additionally, we evaluated the responses of oyster populations and associated macroinvertebrate communities after ten months of restoration using PLA-based versus polyethylene (PE) shell-bag reefs. The results showed no significant difference in oyster recruitment between PLA and conventional plastic substrates (p > 0.05). However, increasing the thickness and surface roughness of the PLA substrates significantly enhanced the recruitment of juvenile oysters (p < 0.05). After ten months, there was no significant difference in oyster abundance between PLA and PE shell bag reefs; however, there was a significant difference in resident macroinvertebrate abundance, with abundances markedly higher on PLA reefs (1372 ± 220 ind./m² vs. 545 ± 90 ind./m²; p < 0.05). This study highlights the potential of PLA as a promising alternative to conventional plastics. However, its rapid degradation limits its applicability in high-energy environments. Furthermore, given that a comprehensive assessment of the microplastic risks associated with its degradation has not yet been conducted, large-scale application is not currently recommended. Full article

Microplastics (MPs), i.e., plastic particles <5 mm, and nanoplastics (NPs), i.e., plastic particles <1 µm, are widespread in the environment. MPs and NPs (MNPs) have also been detected in human tissues. Environmental MNPs exhibit diverse physicochemical properties such as size, shape, and surface degradation. However, most experimental studies have used pristine MNPs, which poorly represent real-world conditions, and only a limited number of studies have focused on preparing environmentally relevant MNPs. Therefore, we focused on the key physicochemical properties of MNPs, particularly their shape, size, and surface degradation, using polyvinyl chloride (PVC) as the model polymer. In this study, fragment and spherical PVC-MNPs were utilized, and surface degradation was introduced through exposure to vacuum ultraviolet (VUV) radiation at a wavelength of 172 nm. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) analysis revealed the formation of additional carbonyl groups after VUV exposure. We investigated the cytotoxic effects of the degraded and non-degraded PVC-MNPs on A549, Caco-2, and THP-1 cells. The results indicated that the degraded PVC-MNP-treated groups induced higher cytotoxic effects than those in the non-degraded groups. Notably, the degraded PVC-NPs induced stronger cytotoxicity than the degraded PVC-MPs. These findings highlight the potential health risks associated with environmental MNPs. Full article

Reliable quantification of microplastics in water remains challenging because most Raman-based methods require filtration, drying, or complex flow systems, which can lead to particle loss and signal instability. Here, we propose a simple dual-laser Raman strategy for the direct, real-time quantification of microplastics in water without pretreatment. By simultaneously integrating backscattering and transmission geometries using two identical 532 nm lasers, spatial variations in Raman scattering cross-sections, arising from particle motion and focal depth fluctuations, are effectively mitigated. The dual-laser configuration enhances Raman intensity by approximately 1.5-fold compared with backscattering and threefold compared with transmission alone (p < 0.001), enabling robust real-time detection with a temporal resolution of 0.1 s. Accurate particle counting is demonstrated using polystyrene (PS) standard beads and further validated for polyamide 6 (PA6) and polyvinyl chloride (PVC) particles with irregular morphologies and broad size distributions, with no false-positive events observed. By prioritizing simplicity and quantitative reliability over ultimate size resolution, the proposed strategy provides a practical approach for routine monitoring of microplastics in drinking water and industrial aqueous systems. Full article

Aging populations have intensified the demand for thermally comfortable and energy-efficient housing, particularly for elderly residents whose diminished thermoregulatory capacity renders them disproportionately vulnerable to indoor temperature fluctuations. Existing senior apartments in cold-climate regions frequently fail to meet age-specific thermal comfort standards, yet systematic retrofit optimization frameworks explicitly tailored to elderly occupants remain scarce. This study presents a data-driven multi-objective optimization framework for building envelope retrofitting, which is validated using on-site temperature measurements from a representative 1980s brick–concrete senior apartment building in Beijing. The framework integrates Latin Hypercube Sampling (LHS) for design space exploration, a Long Short-Term Memory (LSTM) surrogate model for simultaneous prediction of three performance objectives, and Non-dominated Sorting Genetic Algorithm II (NSGA-II) for Pareto-optimal solution generation, with final selection performed via a weighted Mahalanobis distance-based Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS). Optimization targets—annual energy consumption, indoor thermal discomfort hours, and retrofit cost—are parameterized using the age-sensitive comfort thresholds specified in GB 50340-2016. The LSTM surrogate achieved R² values of 0.91–0.93 across all objectives with training–testing differences below 0.02. The optimal retrofit package—Polyvinyl Chloride (PVC) Low Emissivity (Low-E) double-glazed windows (5 + 6A + 5), glass fiber roof insulation (65.25 mm), and Extruded Polystyrene (XPS) external wall insulation (65.39 mm)—reduces annual energy consumption by 47.1% (from 40,867 to 21,626 kWh) and annual thermal discomfort hours by 62.4% (from 2454 °C·h to 923 °C·h). SHapley Additive exPlanations (SHAP)-based sensitivity analysis further identifies wall U-value and roof thickness as the dominant performance drivers. A reproducible and computationally efficient pathway is provided by the proposed framework for evidence-based envelope retrofit decision-making in existing senior residential buildings. Full article

Over the past decades, global plastic demand has steadily increased due to the favorable physicochemical properties of these materials, including low weight, durability, versatility, and low production cost. Among synthetic polymers, polyvinyl chloride (PVC) is one of the most widely produced, accounting for approximately 10% of global polymer production. Suspension polymerization is commonly used for its manufacture because of its high productivity and suitable operational control; however, this process is associated with considerable energy consumption and emissions with potential environmental impacts. In this work, the Waste Reduction (WAR) Algorithm was applied to evaluate the environmental performance of a PVC production process with mass integration and direct water recycling. The Potential Environmental Impact (PEI) was quantified under four scenarios, considering both generation and output rates, as well as different fuel sources. The results showed that the environmental performance of the system strongly depends on the selected system boundaries and on the incorporation of energy-related effects. Under the gate-to-gate scope considered, some scenarios exhibited negative net PEI generation values, indicating that the PEI associated with the outlet streams was lower than that of the inlet streams within the modeled system. However, when energy consumption was included, it became the main contributor to total PEI, reaching 2560 and 3070 PEI/day in Cases 3 and 4, respectively. The toxicological assessment showed that ATP was the only category with positive PEI generation, while natural gas presented the lowest potential environmental impact among the energy sources evaluated. Overall, the process showed comparatively favorable environmental performance within the assumptions and methodological boundaries of the WAR analysis. Full article

Over the past decades, plastics have been increasingly employed to package foods and beverages. Furthermore, foods, nowadays, are kept in contact with plastics for far longer periods than ever before. A number of conventional polymers, i.e., polyethylene (PE), Polypropylene (PP), Ethylene Vinyl Acetate (EVA), Εthylene vinyl alcohol (EVOH) polystyrene (PS), Polyvinyl chloride (PVC), Polyvinylidene chloride (PVDC), polyethylene terephthalate (PET), Polycarbonate (PC), polyethylene naphthalate (PEN), Polyamides (PAs), Polyacrylonitrile (PAN) as well as biodegradable polymers-[Polylactide (PLA)] are used commercially in food packaging applications. Potential interaction of food with the packaging container includes: permeation, migration and flavor scalping. Most food and beverage containers are lined with plastics mainly polyolefins, which due to their low polarity tend to absorb volatile compounds of similar polarity. Absorption of flavor compounds by polymers involves both partitioning and diffusion through the plastic. Absorption is influenced by (i) polymer properties such as polarity, morphology, glass transition temperature, density, free volume, crystallinity and surface area, (ii) flavor compound properties such as structure, concentration, and polarity, and (iii) external factors such as temperature, time of contact, relative humidity and the proximity of other compounds. Based on the above, it is apparent that flavor scalping should be among one of the food packaging industry priorities in order to efficiently preserve the quality of packaged food flavor. This review highlights the various factors affecting the scalping process, as well as the consequences of flavor scalping in various food and beverage commodities. The review covers the period 1990–2925 and used the LitChemPlast data base for literature search. Full article

Background/Objectives: Phthalates are a group of organic compounds widely used for enhancement in flexibility and transparency of polyvinyl chloride (PVC) products. Exposure to phthalate-containing substances has been shown to affect brain function, particularly in learning and memory processes. Quercetin is a plant-derived flavonoid with remarkable anti-oxidant and anti-inflammatory potential. This study investigated the possible protective effects of quercetin on spatial learning and memory, histomorphometric changes, and hippocampal expression of inflammatory cytokines (TNF-α and IL-6) in male mice exposed to di(2-ethylhexyl) phthalate (DEHP). Methods: A total of 42 male mice were divided into seven groups. Quercetin was administered orally at doses of 25 and 50 mg/kg/day, either alone or in combination with DEHP (200 mg/kg/day). Following the final day of the treatment, spatial learning and memory were assessed by the Morris Water Maze test. Hippocampal tissues were sampled for Nissl, H&E, and immunofluorescence staining. Quantitative real-time PCR was used to measure the expression of TNF-α and IL-6. Results: The DEHP group exhibited significant impairments in learning and memory, neuronal damage, and cellular disorganization in the hippocampus, along with increased astrocyte activation and elevated expression of TNF-α and IL-6. On the other hand, quercetin supplementation significantly reduced these inflammatory markers and histological damages and also improved spatial learning and memory. Conclusions: Overall, quercetin improves cognitive function that is associated with attenuating astrocyte activation and inflammation. Full article

While the utilization of waste polymers in asphalt mixtures is widely studied, the specific influence of additive geometry on performance mechanisms remains underexplored. This study presents a multi-scale performance assessment of asphalt mixtures modified with waste Polyvinyl Chloride (PVC) foils. Waste PVC foils were processed into two distinct geometries, “Wiry” and “Random”, and incorporated into mixture at dosages ranging from 5% to 12.5% by weight of bitumen via the dry process. At the macro-scale, Semi-Circular Bending, Hamburg Wheel Tracking, Repeated Creep, and Modified Lottman tests were conducted. At the micro-scale, Scanning Electron Microscopy and EDS analyses were employed to investigate interfacial adhesion. The results demonstrated that the “Wiry” geometry significantly outperformed the “Random” by establishing a three-dimensional reinforcement network. Specifically, the mixture modified with 7.5% “Wiry” PVC yielded the highest Flexibility Index of 24.17, representing a 3.7-fold improvement. Furthermore, this optimum dosage enhanced high-temperature stability and maintained moisture resistance (TSR > 85%), whereas dosages exceeding 10% caused agglomeration and performance loss. Microstructural imaging indicated that the fibrous morphology and calcite-rich surface of the “Wiry” additive facilitate superior mechanical interlocking. Consequently, this study suggests that optimizing waste PVC geometry is as critical as dosage for maximizing the durability and sustainability of flexible pavements. Full article

The rapidly growing concern over the hazardous impact of phthalates on the environment and public health has led to a critical need for alternative and environmentally friendly plastics. Plasticizers developed from natural materials represent one possible solution. This paper explores four types of renewable feedstocks (sorbitol/polyols, glycerin, cardanol from cashew nutshell liquid, and limonene from citrus peels) as sources for developing alternative plasticizer systems. Key areas explored include the type of feedstock utilized, the methods used for extracting or processing the feedstocks, the nature of the chemical modification processes (e.g., esterification, epoxidation, etherification, or reactive grafting) applied to generate the respective plasticizers, and the resultant physical and mechanical properties. The performance of each plasticizer system in polymers such as PVC, PLA, and polysaccharide-based bioplastics is evaluated, alongside the compatibility with biological tissues, toxicological properties, biodegradability, and chemical migration into food simulants. The feasibility of each family of plasticizers is also assessed from an economic perspective, including availability of the feedstocks, economies of scale associated with large-volume production, and competitive pricing relative to established petroleum-derived plasticizers. Overall, sorbitol/polyol and glycerin derivative families have reached a level of maturity that provides a good balance of processability, food-contact safety, and biodegradability. Cardanol-based systems provide an attractive option where aromatic functional groups and combined plasticization–stabilization effects are needed. Limonene-derived plasticizer systems appear promising for use in PLA, but their broader utility may be limited by volatility, strong odors, and susceptibility to oxidation. Common issues identified across all four families include chemical migration into food products, regulatory approval, and the need for detailed life-cycle assessments. Full article

The present study aimed to investigate the effects of polyvinyl chloride microplastics with different sizes on the growth, intestinal and hepatic health of turbot (Scophthalmus maximus L.) at 3 and 9 weeks of exposure. Three diets were formulated: a control diet with no microplastics, a diet containing 2% micrometer-sized plastics (MPs), and a diet containing 2% nanoplastics (NPs), with four replicates (40 fish/tank, 12 tanks total). The results showed that MPs and NPs had no significant effects on the growth performance of turbot. Analyses of intestinal histology and gene expression (intestinal barrier-related and antioxidant-related genes) indicated that the turbot intestine exhibited a certain degree of tolerance and adaptability to MPs and NPs exposure. Observations of liver histology and analyses of gene expression (inflammatory cytokines, apoptosis-related, and antioxidant-related genes) revealed that the liver damage induced by microplastics in turbot exhibited obvious size-dependent and time-cumulative effects, with NPs exerting a stronger impact. Compared with MPs, long-term exposure to NPs can induce obvious intestinal microbiota dysbiosis in turbot. In summary, particle size and exposure duration are important factors regulating the impacts of PVC microplastics on the intestinal and hepatic health of turbot. Full article

Polyvinyl chloride (PVC) is widely used in engineering applications; however, its inherent thermal instability associated with dehydrochlorination limits its processing window and long-term performance. While blending with thermoplastic polyurethane (TPU) and plasticization are common strategies to improve flexibility, their combined influence on the thermal behavior and stability of PVC, particularly when bio-based plasticizers are employed, has not been thoroughly investigated. In this study, the thermal behavior and stability of PVC/TPU blends plasticized with glycerol diacetate monolaurate, a bio-based plasticizer derived from waste cooking oil, were investigated. Dynamic mechanical analysis (DMA) and Fourier transform infrared spectroscopy (FTIR) were used to examine segmental mobility and intermolecular interactions, while scanning electron microscopy (SEM) provided insight into microstructural organization. Thermal stability was evaluated through conductivity-based dehydrochlorination measurements, complemented by thermogravimetric and derivative thermogravimetric analyses (TGA/DTG) to assess degradation behavior. The results showed that neither TPU nor the bio-plasticizer alone improved the resistance of PVC to dehydrochlorination. In contrast, ternary PVC/TPU/bio-plasticizer blends exhibited a pronounced delay in HCl evolution, accompanied by a more homogeneous phase distribution and interaction-driven modification of the molecular environment. TGA/DTG analysis indicated that this stabilization arises from altered degradation kinetics rather than a simple shift in degradation onset. Overall, the findings clarify the thermal behavior of PVC-based blends and demonstrate a sustainable formulation approach for achieving flexible and thermally balanced PVC materials while reducing reliance on potentially toxic phthalate plasticizers. Full article

The study of river basins is key to understanding the dynamics of microplastic (MPs) generation, transport, and accumulation in regions where various productive activities converge and waste management is limited. The objective of this study was to characterize economic activities in the Tecolutla River basin, Mexico, to identify risk factors associated with MPs generation and release throughout the production chain. A descriptive applied research study was conducted using a structured questionnaire administered to 19 economic units distributed across seven municipalities in the Tecolutla River basin, Veracruz, Mexico. The instrument allowed for the evaluation of the use of plastic materials in inputs, production processes, final products, and waste management practices. Among the economic units analyzed (n = 19), 94.7% reported the use of polymeric materials, with a predominance of thermoplastics such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polypropylene (PP), which have a high potential for secondary fragmentation. Within the tertiary sector, accommodation and food preparation services account for the highest proportion of units with limited separation and recycling practices. Activities in the secondary sector, especially the textile and construction industries, showed a high potential for releasing this pollutant due to the use of synthetic fibers, composite materials, and the absence of retention systems. The results provide a basis for the design of mitigation strategies targeting priority productive sectors at the watershed scale. Full article

Background: The ability of synthetic plastics to persist in the environment and the accumulation of microplastics has intensified the need to explore biological mechanisms capable of interacting with, and possibly degrading, polymeric materials. Microbial enzymes that have extensive catalytic flexibility represent promising candidates in this context. Aim: This study set out to examine the molecular interaction patterns and dynamical stability of Pseudomonas aeruginosa elastase (LasB) with representative structural fragments of typical synthetic plastics to assess the suitability of the enzyme to polymer-derived substrates. Methods: The crystallographic structure of LasB (PDB ID: 1EZM) was retrieved from the Protein Data Bank and pre-prepared with the help of AutoDock4.2.6 Tools. Those polymer-derived ligands that were associated with the major industrial plastics such as polyamide (PA), polyvinyl chloride (PVC), polycarbonate (PC), poly-ethylene terephthalate (PET), polymethyl methacrylate (PMMA), and polyurethane (PUR) were retrieved in the PubChem database and geometrically optimized with the help of the MMFF94 force field. AutoDock Vina, with a specific grid box around the catalytic pocket, including Zn²⁺ ion, was used to perform molecular docking simulations. PyMOL and BIOVIA Discovery Studio software were used to analyze binding conformations, interaction residues and types of intermolecular contacts. Phosphoramidon, a known metalloprotease inhibitor, served as a positive control to confirm the docking protocol. Additional assessment of the structural stability and conformational behavior of the enzyme–ligand complexes was conducted by molecular dynamics (MD) simulations with the Desmond engine and explicit solvent model in a 50 ns trajectory using the OPLS4 force field. RMSD, RMSF, radius of gyration, hydrogen bonding analysis and solvent accessibility parameters were used to measure structural stability. Results: The docking experiment showed varying binding affinities with the test polymers. Polycarbonate (−5.774 kcal/mol) and polyurethane (−5.707 kcal/mol) had the highest in-teractions with the LasB catalytic pocket, polyamide (−5.277 kcal/mol) and PET (−4.483 kcal/mol) followed PMMA and PVC, which had weaker affinities. The following were the important residues involved in interaction networks: Glu141, His140, Val137, Arg198, Tyr114, and Trp115 that were implicated in interaction networks with hydrophobic interactions, π-cation interactions and van der Waals forces that were the major stabilization forces. MD simulations had stabilized complexes, and RMSD values were found to be within acceptable ranges of stability, and ligand-specific changes (around 1.0-3.2 A), which is also in line with stable protein-ligand systems. Phosphoramidon used as a positive control had an RMSD of 1.205 A which is within this stability range. PCA determined various ligand-bound conformational states of LasB with PA in com-pact state, PC and PVC in intermediate states and PUR, PMMA and PET in ex-panded conformations, indicating structur-al stability and adaptability of the binding pocket. Conclusion: These findings show that LasB has a structurally flexible catalytic pocket that can accommodate a wide range of polymer-derived ligands. These results offer an insight into the recognition of enzymes with polymers at the molecular level and also indicate that LasB might help in the interaction of microorganisms with synthetic plastics in environmental systems. Full article