Plasticized Poly Vinyl Chloride Research Articles

Pollution characteristics, sources, and health risks of phthalate esters in ambient air: A daily continuous monitoring study in the central Chinese city of Nanchang

In recent years, the atmospheric pollution caused by phthalate esters (PAEs) has been increasing due to the widespread use of PAE-containing materials. Existing research on atmospheric PAEs lacks long-term continuous observation and samples from cities in central China. To investigate the pollution characteristics, sources, and health risks of PAEs in the ambient air of a typical city in central China, daily PM2.5 samples were collected in Nanchang from November 2020 to October 2021. In this study, the detection and quantification of six significant PAE contaminants, namely diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), Di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DnOP), and diisodecyl phthalate (DIDP), were accomplished using gas chromatography and mass spectrometry. The results revealed that the concentrations of DEP, DnBP, DEHP, and DnOP were relatively high. Higher temperatures promote the volatilization of PAEs, leading to an increase in the gaseous and particulate PAE concentrations in warm seasons and winter pollution scenarios. The results of principal component analysis show that PAEs mainly come from volatile products and polyvinylchloride plastics. Using positive matrix factorization analysis, it is shown that these two sources contribute 67.0% and 33.0% in atmosphere PAEs, respectively. Seasonally, the contribution of volatile products to both gaseous and particulate PAEs substantially increases during warm seasons. The residents in Nanchang exposed to PAEs have a negligible non-cancer risk and a potential low cancer risk. During the warm seasons, more PAEs are emitted into the air, which will increase the toxicity of PAEs and their impact on human health.

Effect of ionic liquids on structure and electromechanical properties of plasticized polyvinyl chloride (PVC) gels

Polyvinyl chloride (PVC) gels, as electroactive polymers, have various applications in the fields of soft actuators and sensors. The relationship between the structure and electromechanical properties of PVC gels, however, has not been fully understood so far. In this work, the effect of different alkyl chain length of 1-allyl- imidazolium cations of tetrafluoroborate (BF4)-based ionic liquid (IL) on structure, mechanical and dielectric properties, bending actuation, sensing and electroadhesion properties of plasticized polyvinyl chloride/dibutyl adipate (PVC/DBA) gel were investigated. The interaction between DBA and ILs in PVC/DBA/IL gels leads to the disruption of interactions between inter-DBA molecules and subsequent formation of DBA-rich phases with DBA/IL complexes. The number of DBA-rich phases in PVC/DBA/IL gels increases as the alkyl chain length of the cation in IL increases, due to an enhanced interaction between DBA and ILs with an increase in the alkyl chain length of the cation in IL. The Young's modulus of the PVC/DBA gel was slightly reduced, while the dielectric constant significantly increased when IL was added. Additionally, the bending actuation properties and capacitance pressure sensing sensitivity of the PVC/DBA/IL gel increased with an increase in the alkyl chain length of the cation of IL. However, there was an opposite trend observed for electroadhesion peel strength. Among the studied PVC/DBA/IL gels, the bending displacement, pressure sensing sensitivity, and electroadhesion peel strength of PVC/DBA/IL gel with 3.2 wt% of 1-allyl-3-butylimidazolium tetrafluoroborate ([ABIM]BF4) increased by 2.6 times, 7.5 times, and 1.7 times compared to PVC/DBA gel, respectively. These results provide new insights into understanding the relationship between structure and electromechanical properties of PVC gels for their application in actuation, sensing, and electroadhesion integrated soft grippers.

Poly(vinyl chloride)/Nanocarbon Composites for Advanced Potentiometric Membrane Sensor Design.

Polymer nanocomposites filled with carbon nanoparticles (CNPs) are a hot topic in materials science. This article discusses the current research on the use of these materials as interfacial electron transfer films for solid contact potentiometric membrane sensors (SC-PMSs). The results of a comparative study of plasticized poly (vinyl chloride) (pPVC) matrices modified with single-walled carbon nanotubes (SWCNTs), fullerenes-C60, and their hybrid ensemble (SWCNTs-C60) are reported. The morphological characteristics and electrical conductivity of the prepared nanostructured composite films are reported. It was found that the specific electrical conductivity of the pPVC/SWCNTs-C60 polymer film was higher than that of pPVC filled with individual nanocomponents. The effectiveness of this composite material as an electron transfer film in a new potentiometric membrane sensor for detecting phenylpyruvic acid (in anionic form) was demonstrated. Screening for this metabolic product of phenylalanine in body fluids is of significant diagnostic interest in phenylketonuria (dementia), viral hepatitis, and alcoholism. The developed sensor showed a stable and fast Nernstian response for phenylpyruvate ions in aqueous solutions over the wide linear concentration range of 5 × 10-7-1 × 10-3 M, with a detection limit of 10-7.2 M.

Effect of spontaneous degradation of ion-selective optodes receptor materials on sensors performance. Where is the catch?

Interest in application of biodegradable polymers as matrix for ion-selective sensors, including optodes is likely to increase. However, finding an alternative for plasticized poly(vinyl chloride) or polyacrylates, requires among others consideration if spontaneous changes in these materials affect the analytical performance of sensors. In this work we study ion-selective optodes prepared using biodegradable matrix: p-polycaprolactone and acetyl tributyl citrate using classical constituents: optically silent ionophore and chromoionophore as optical transducer. The effect of spontaneous changes of sensor constituents on its performance was studied. It was confirmed that hydrolysis of receptor is occurring leading to change of the matrix composition. Surprisingly it was found that the key factor affecting performance of sensor is spontaneous transformation of the dye embedded within it, typically considered as stable within the sensor matrix. N-octadecanoyl-Nile blue, i.e. chromoionophore I, undergoes acidic hydrolysis leading to formation of Nile blue and Nile red, and ultimately resulting in decreased sensor performance. The hydrolysis of chromoionophore in plasticized polycaprolactone matrix is significantly affected by incorporation of carbon dioxide to the solution containing nanoprobes. As model sensors hydrogen or potassium ions selective optodes were tested.

Trash into treasure: Chemical upcycling of poly(ɛ-caprolactone) waste plastic to plasticizer with excellent plasticizing performance and migration resistance

In recent years, with the increasingly serious environmental pollution, the achievement of a truly circular materials economy approach to sustainability has attracted the attention of scientists. In this paper, we proposed an approach that combined the chemical recycling of poly(ɛ-caprolactone) (PCL) plastic with the synthesis of a green plasticizer to promote the development of plastics' reutilization. An efficient alcoholysis strategy was employed to achieve the precise chain scission of PCL into short-chain PCL (sc-PCL), which was subsequently blended with polyvinyl chloride (PVC). The excellent compatibility of PVC/sc-PCL blend was characterized through differential scanning calorimetry (DSC) and solubility parameters. Thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) confirmed that the thermostability and plasticity of the plasticized PVC samples were superior to those of most commercial plasticizers' plasticized samples. Meanwhile, the exceptional extraction and migration resistance of PVC/sc-PCL implied that sc-PCL was capable to modify PVC as an ideal plasticizer. The flexible macromolecular structure of sc-PCL and the high percentage of polar ester groups made sc-PCL closely entangled with PVC, thus exhibiting excellent plasticizing properties. This trash into treasure strategy was also applicable to commercial PCL products, which will open up a new direction for chemical recycling of plastics as well as design and synthesis of green plasticizers.

Optimization of innovative optical sensor for zirconium determination and capturing from environmental samples

A highly sensitive bulk optode membrane, specifically engineered for the identification of zirconyl (ZrO2+) ions, has been successfully created. The membrane is composed of plasticized polyvinyl chloride (PVC), dibenzodylmethane (DBM) acting as the chromoionophore, 2-amino-4-(3-chlorophenylazo)pyridine-3-ol (ACPAP) serving as the ionophore, and sodium tetraphenylborate (NaTPB) included as an ionic additive. The sensing membrane undergoes a color change from orange to blue when exposed to ZrO2+ ions at pH 6.5. The preparation parameters of the sensor and the determination of ZrO2+ ions were meticulously optimized. In addition to showcasing reproducibility, extended stability, and a comparatively long lifespan, the suggested sensor membrane displays remarkable selectivity for ZrO2+ ions, effectively discerning them from a spectrum of alkaline earth, heavy and transition metal ions, and actinides. The sensor delivers a calibration response tailored for ZrO2+ ions across a concentration spectrum spanning 7.5–185 ng mL−1, establishing limits of quantification and detection at 7.3 and 2.2 ng mL−1, respectively. Demonstrating a rapid response within a timeframe of under 5.0 min. The sensor consistently delivered highly reproducible results, as evidenced by relative standard deviation (RSD) of 1.67 % and 1.55 % for Zr4+ concentrations at 100 and 150 ng mL−1.This underscores the precision and reliability of the sensor. Regeneration of the optode can be easily accomplished by employing 0.05 M HCl. Effectively employed across a spectrum of samples, including water, soil, plant materials, and ore solutions, the proposed optical sensor proves to be a valuable instrument for determining ZrO2+ ions in diverse environmental and analytical scenarios.

Application of a dual depressant system and microwave irradiation for flotation-based Separation of Polyethylene Terephthalate, Polyvinyl Chloride, and Polystyrene Plastics

The absence of an effective technique for the individual separation of plastics within a plastic mixture remains a paramount concern in the domain of plastic waste management. Recently introduced, the floatation technique has emerged as a method for segregating specific plastics, such as polystyrene (PS), polyethylene terephthalate (PET), and polyvinyl chloride (PVC), from mixed waste streams. This separation process involves the utilization of traditional dual depressants (chemical agents). The study investigated the impact of pre-microwave irradiation of plastic surfaces at varying microwave output powers (20-100%) on the floatation behavior of each plastic. Additionally, the influence of depressant concentration (200-1600 mg/L) on plastic floatation was examined. The results revealed that pre-microwave irradiation at different output powers and varying depressant concentrations significantly affected the sink-float behavior of the studied plastics, with the exception of PET. It was observed that the microwave irradiation altered the number and type of active sites on the plastics' surfaces. Notably, there was no discernible regular trend in the flotation of plastic with an increase in microwave output power. The outcomes were substantiated by conventional identification techniques, including contact angle (θ) measurement, scanning electron microscopy (SEM) images, and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) spectra analysis. Equations derived through the use of the design of experiment software (Design-Expert®) demonstrated a commendable alignment between the predicted and actual values of plastic flotation. This underscores the efficacy of the applied methodology in forecasting and validating the outcomes of the floatation process.

High-efficiency co-liquefaction of low-rank coal and PAEs-rich PVC waste in supercritical water: Products upgrading and dechlorination

With the extensive use of phthalates (PAEs)-rich polyvinyl chloride (PVC) plastic products, the recycling of PAEs-rich PVC waste has become a great challenge. Meanwhile, the efficient utilization of low-rank coal is important in China due to the abundant reserves. In this study, a high-efficiency co-liquefaction treatment of PAEs-rich PVC waste and low-rank coal (Inner Mongolia lignite) was developed by using supercritical water (SCW) process based on the interaction between the two kinds of waste. The effects of temperature, time, solid-to-liquid ratio (MCoal+PVC:MH2O), and mass ratio of coal-to-PVC (MCoal:MPVC) on the co-liquefaction conversion, composition of liquefied oil and dechlorination of PVC waste were investigated. The co-liquefaction of low-rank coal and PAEs-rich PVC waste had a significant positive synergistic effect with a maximum synergistic efficiency of 7.53% in the temperature range of 350–450 °C. The conversion ratio of low-rank coal and PAEs-rich PVC waste by SCW co-liquefaction increased from 59.71% to 74.92% with the increase of reaction temperature from 350 to 450 °C. PAEs-rich PVC waste could be almost completely dechlorinated (>98%) by the SCW co-liquefaction process, and more than 90% of the DEHP could be decomposed. The addition of PAEs-rich PVC waste resulted in a significant decrease of the percentage of heteroatom-containing compounds in the oil products by the co-liquefaction. At 450 °C, the co-liquefaction oil contained 69.16% of hydrocarbons and 6.14% of phenolic compounds. Different from supercritical water gasification, the purpose of SCW co-liquefaction in this study is to improve the coal liquefaction conversion ratio and oil quality by introducing the PAEs-rich PVC waste. The synergistic SCW treatment of PAEs-rich PVC waste and low-rank coal has good application prospects in products upgrading of low-rank coal and safe recycling of PAEs-rich PVC waste plastics.

EVALUATION OF THE THERMAL-OXIDATIVE STABILITY OF A HALOGEN-CONTAINING PLASTICIZER-FIRE RETARDANT

The importance of assessing the indicators of thermal-oxidative stability of plasticizers that are part of polymer compositions for ensuring high performance indicators during their processing and operation of finished products is noted. When using brominated organic compounds of the aromatic series, a short burning time of polymer compositions and a significant smoldering time have been established. The use of flame retardants containing a halogen in the aliphatic radical leads to a decrease in the smoldering time and an increase in the duration of combustion due to a decrease in the thermal stability of the material at the stage of decomposition. It is indicated that bromine-containing compounds give the best inhibition effect compared to chlorine-containing compounds due to a decrease in the carbon-bromine bond breaking energy compared to the carbon-chlorine bond energy. The decomposition parameters of the brominated plasticizer-fire retardant have been established. It is shown that the thermal decomposition of the brominated plasticizer occurs in two stages, corresponding to the elimination of bromine from the aliphatic radical in the temperature range 473 K – 573 K and the decomposition of phthalic acid esters in the range 603 K – 623 K. The beginning of intensive decomposition corresponds to 443 K. The maximum of the first stage of decomposition is at the point corresponding to 501 K, the second - 606-623 K. It was noted that the bromine-free plasticizer decomposes intensively, starting from 503 K and reaches the maximum decomposition rate at 611 K. The maximum loss of the bromine-free plasticizer was established at 27%, brominated - 50.9% of the mass of the sample. It has been confirmed that the presence of bromine atoms in the plasticizer adversely affects its thermal stability. The influence of the degree of halogenation of an unsaturated plasticizer on the nature of its thermal-oxidative degradation in the temperature range corresponding to the technological parameters of processing polymeric materials at elevated temperatures of 413-443 K has been studied. It is shown that an increase in the content of bromine in the plasticizer when performing technological operations for the processing of polymer compositions in the specified temperature range and the duration of exposure to elevated temperatures within one hour does not significantly affect the mass fraction of bromine in the plasticizer. A kinetic equation for the reaction of thermal decomposition of a bromine-containing plasticizer-flame retardant of the phthalate type, accompanied by the elimination of hydrogen bromide, is proposed. The activation parameters of the hydrogen bromide evolution reaction were determined for the temperature range of maximum decomposition of a brominated phthalate plasticizer with a bromine content in the range of 5% – 25%. It is shown that the activation energy of hydrogen bromide elimination depends on the bromine content in the plasticizer and decreases by 23% with an increase in the degree of bromination. It is shown that the temperature range of maximum decomposition of the brominated fire retardant plasticizer, corresponding to 473 K – 573 K, allows using it as a secondary plasticizer for polyvinyl chloride without reducing the thermal stability of the base.

Comparative aspects on the epoxidation of soybean oil and high oleic soybean oil

AbstractSoybean oil (SO) epoxidation is an extensively studied method to generate a sustainable plasticizer for polyvinyl chloride (PVC). Standard soybean oil is composed of triglycerides whose fatty acids are primarily unsaturated linoleic, oleic, and linolenic acids. High oleic soybean oil (HOSO) is collected from a soybean variety higher in oleic acid than other acids. The present study focused on a preliminary comparison of the epoxidation reaction behavior between SO and HOSO, conducted isoperibolically and without catalysts. The experimental data were modeled by a kinetic model. Considerable differences in the temperature and oxirane index profiles suggest that the epoxidation of HOSO tends to be faster and with a more intense heat release rate than the epoxidation of SO, which was confirmed by the results of estimated kinetic constants. The data collected and shared herein suggest that a first epoxy group generated may cause steric hindrance to slow the epoxidation in the second and third double bonds of the oil.

Organocatalyst Promoted Efficient Synthesis of Carboxylic Acid Esters and its Application as Plasticizer for Polyvinyl Chloride

AbstractThe present work is related to the synthesis of a carboxylic acid ester using lab synthesized triphenylphosphonium triflate catalyst and its application as a plasticizer for polyvinyl chloride (PVC) processing. The high thermal stability of this organocatalyst allows the synthesis of terephthalic acid di‐esters with high boiling alcohols such as 1‐butanol, 2‐ethyl hexanol with higher yield in the range of 55–97 %. Different ester derivatives like dioctyl phthalate (DOP), dioctyl terephthalate (DOTP), n‐butyl benzoate, dibutyl terephthalate, dibutyl phthalate, and di‐dodecanol terephthalate have been synthesized using triphenylphosphonium triflate organocatalyst. These synthesized ester derivatives are characterized using 1H NMR, GC‐MS and HPLC. The purity of different synthesized esters was in the range of 80–99 %. The synthesized Dioctyl terephthalate (DOTP) was used as a plasticizer in PVC and compared the results with commercial DOP plasticizer performance for PVC. The PVC/DOTP composition exhibited comparable performance in terms of mechanical properties like tensile and flexural strength and modulus. No significant change found in hardness and impact strength of both the compositions. Ease of processing observed in case of PVC/DOTP composition due to lower torque as compared to PVC/DOP composition. This indicates DOTP can be a potential alternative to the traditional dioctyl phthalate (DOP) plasticizer for PVC processing.

The influence of phenolic resin modified by cardanol on improving the processability of PVC

Polyvinyl chloride (PVC) is a kind of plastic widely used in different industries, and it is a hard and brittle polymer that requires the use of plasticizers to improve processability. Phthalates are small molecule plasticizers of PVC, which are easy to volatilize and migrate while improving the processing properties of PVC. We propose alternatives based on phenolic resin prepolymer modified by cardanol (CPF), which were added to PVC as reactive plasticizer and can improve the processability of PVC. The effects of CPF on the rheological properties and migration resistance of plasticized PVC were studied, and the changes in the physical properties of blends were also discussed. The results showed that the viscosity of PVC melt can be reduced by two orders of magnitude by adding 30 wt% prepolymers at 180°C compared with PVC without CPF, which indicated that CPF can be used to reduce the processing temperature of PVC. The test results of migration resistance showed that the mass loss rate of the blend with 30 wt% prepolymers was less than 1 wt% after curing, however, the mass loss rate of the blend with 30 wt% dioctyl phthalate (DOP) was more than 12% after 5 days of testing. When the PVC/CPF mass ratio was between 60/40-70/30, the maximum values of tensile strength and elastic modulus are 64.4 MPa and 3.2 GPa, respectively, which showed the addition of CPF could significantly improve the tensile strength and elastic modulus of the blend system compared with PVC without CPF. Especially, the thermal stability of CPF is better than that of DOP, CPF exhibits the maximum thermal decomposition temperature (410°C), higher than that of DOP (170°C), which can adapt to higher processing temperature.

Improving the Hydrophobicity of Plasticized Polyvinyl Chloride for Use in an Endotracheal Tube.

An endotracheal tube (ETT) is a greatly appreciated medical device at the global level with widespread application in the treatment of respiratory diseases, such as bronchitis and asthma, and in general anesthesia, to provide narcotic gases. Since an important quantitative request for cuffed ETTs was recorded during the COVID-19 pandemic, concerns about infection have risen. The plasticized polyvinyl chloride (PVC) material used to manufacture ETTs favors the attachment of microorganisms from the human biological environment and the migration of plasticizer from the polymer that feeds the microorganisms and promotes the growth of biofilms. This leads to developing infections, which means additional suffering, discomfort for patients, and increased hospital costs. In this work, we propose to modify the surfaces of some samples taken from commercial ETTs in order to develop their hydrophobic character using surface fluorination by a plasma treatment in SF6 discharge and magnetron sputtering physical evaporation from the PTFE target. Samples with surfaces thus modified were subsequently tested using XPS, ATR-FTIR, CA, SEM + EDAX, profilometry, density, Shore A hardness, TGA-DSC, and biological antimicrobial and biocompatibility properties. The obtained results demonstrate a successful increase in the hydrophobic character of the plasticized PVC samples and biocompatibility properties.

Effects of biodegradable and conventional microplastics on the intestine, intestinal community composition, and metabolic levels in tilapia (Oreochromis mossambicus)

Despite growing interest in conventional microplastics (CMPs) and their toxicological effects on aquatic species, little is known about biodegradable microplastics (BMPs) and their corresponding implications for aquatic life. Here, tilapia (Oreochromis mossambicus) were semi-statically exposed for 14 days to the bio-based plastic polylactic acid (PLA, 100 μg/L, 2.52 ± 0.46 μm) and the petroleum-based plastic polyvinyl chloride (PVC, 100 μg/L, 1.58 ± 0.36 μm). The results showed that ingesting the above two types of microplastics (MPs) led to oxidative stress in the fish gut, and damage to gut tissues and organelles, and PLA resulted in more obvious gut tissue edema than PVC. Furthermore, PLA caused increased levels of gut microbiota dysbiosis and a decrease in the abundance of the genus Cetobacterium, which is linked to vitamin B-12 synthesis, whereas an opposite relationship was observed on PVC. Metabolomic analysis indicated that PVC caused a significant down-regulation of orotic acid, co-metabolite of folic acid with vitamin B-12, while PLA did not affect orotic acid, which may lead to the accumulation of folic acid in fish. The joint analysis found that MPs disturbed gut metabolism homeostasis, implying that abnormal gut microbiota metabolites may be a key mechanism for MPs to induce tissue damage and oxidative stress in the gut. Overall, this study systematically illustrates the differential toxic effects of BMPs and CMPs on tilapia through gut microbiota and metabolite interactions, which will contribute to assessing the risks of BMPs to organismal health.

Investigation of Cinnamic Acid Derivatives as Alternative Plasticizers for Improved Ductility of Polyvinyl Chloride Films.

This study investigates the viability of cinnamic acid derivatives as alternative plasticizers for polyvinyl chloride (PVC) films by addressing concerns about conventional phthalate-based options that pose health and environmental risks. By theoretical modeling, this research evaluates the compatibility between various cinnamic acid-based plasticizers and the PVC matrix, which suggests their potential effectiveness. Additionally, the incorporation of these plasticizers notably enhances the tensile properties of PVC films, particularly in terms of ductility and elongation at break by surpassing the neat PVC. Moreover, cinnamic acid-based plasticizers induce a drop in the glass transition temperature and storage modulus by, thereby, enhancing flexibility and reducing brittleness in the material. Although a slight reduction in the onset degradation temperature is observed, it does not impede the industrial processing of PVC plastisols at temperatures up to 190 °C. Optically, plasticized films exhibit high transparency with minimal UV and visible light absorption, which renders them suitable for applications necessitating clarity. The water vapor transmission rate analysis indicates increased permeability, influenced by molecular volumes. Atomic force microscopy reveals a compacted, homogeneous surface structure in most plasticized films, which signifies improved film quality. Thus, utilizing cinnamic acid derivatives as PVC plasticizers offers substantial mechanical and structural benefits, while compatibility ensures effective integration by contributing to environmentally sustainable PVC formulations with enhanced performance.

Transport of uncharged redox species through an organic thin film analyzed under pseudo-impermeable boundary conditions

The mathematical models that are typically employed for describing the responses of chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) of guest species that diffuse into an impermeable host material have been adapted for the case of an electrode covered with an organic thin film (TF). The mathematical solution has been used for simulating and fitting the electrochemical responses of ferrocene-methanol (FcMeOH) on the surface of a working electrode modified with a TF of highly plasticized polyvinyl chloride. The analysis of chronoamperometric profiles allows us to determine the diffusion coefficient and the concentration of the electroactive species in the TF. Also, from those values is possible to estimate values for the partition coefficient of FcMeOH between an aqueous solution and an organic film, as well as for the film thickness.The EIS responses exhibited remarkable consistency with the CA results. In the high frequency range, the TF system displayed a Warburg-type behavior, while at low frequencies, Nyquist's plot revealed a pronounced capacitive behavior due to the limited insertion of FcMeOH. The fit of CA and EIS responses yielded a set of resistance and capacitance values from which it is possible to infer that the diffusion resistance is significantly larger than the charge transfer resistance and that there are no trapping sites that could be associated with imperfections in the lattice of PVC. To our knowledge, this is the first instance where a model developed for the electrochemistry of insertion has been adapted to elucidate the partitioning of redox species between two immiscible liquids, followed by a charge transfer electrode process.

Accurate determination of 11 representative phthalates and di(2-ethylhexyl) terephthalate in polyvinyl chloride using isotope dilution-gas chromatography/mass spectrometry

Phthalates are mainly used as plasticizers in polyvinyl chloride (PVC). However, prolonged exposure to phthalates poses considerable risks to human health. Consequently, the utilization of phthalates in consumer products is subject to regulations, with a defined threshold of 0.1 %. In this study, we developed an accurate and simultaneous method for determination of 11 representative phthalates and a non-phthalate plasticizer (di(2-ethylhexyl) terephthalate, DEHT) in PVC as a higher-order reference method. Homogeneously prepared PVC samples, each containing approximately 0.1 % of the target plasticizer compounds, were analyzed using gas chromatography-mass spectrometry (GC–MS) with deuterium-labeled phthalates and DEHT. The developed method could effectively separate and quantify all target plasticizers without interference with each other and potential overlap between the isomeric forms of phthalates, di-isodecyl phthalate, and di-isononyl phthalate. The developed method has high-order metrological quality, exhibiting exceptional selectivity, accuracy, repeatability (≤ 2.17 %), reproducibility (≤ 2.16 %), and relative expanded uncertainty (≤ 5.6 %). This analytical method is thus suitable for accurately assessing the target plasticizer levels in PVC products for ensuring compliance with the established 0.1 % threshold. This method was successfully applied to quantify twelve distinct plasticizers in PVC products obtained from the Korean market, validating its effectiveness and reliability in real-world scenarios.

Quantitative proteomics reveals the neurotoxicity of trimethyltin chloride on mitochondria in the hippocampus of mice

Trimethyltin chloride (TMT) is a potent neurotoxin widely used as a constituent of polyvinyl chloride plastic in the industrial and agricultural fields. However, the underlying mechanisms by which TMT leads to neurotoxicity remain elusive. In the present study, we constructed a dose and time dependent neurotoxic mouse model of TMT exposure to explore the molecular mechanisms involved in TMT-induced neurological damage. Based on this model, the cognitive ability of TMT exposed mice was assessed by the Morris water maze test and a passive avoidance task. The ultrastructure of hippocampus was analyzed by the transmission electron microscope. Subsequently, proteomics integrated with bioinformatics and experimental verification were employed to reveal potential mechanisms of TMT-induced neurotoxicity. Gene ontology (GO) and pathway enrichment analysis were done by using Metascape and GeneCards database respectively. Our results demonstrated that TMT-exposed mice exhibited cognitive disorder, and mitochondrial respiratory chain abnormality of the hippocampus. Proteomics data showed that a total of 7303 proteins were identified in hippocampus of mice of which 224 ones displayed a 1.5-fold increase or decrease in TMT exposed mice compared with controls. Further analysis indicated that these proteins were mainly involved in tricarboxylic acid (TCA) cycle and respiratory electron transport, proteasome degradation, and multiple metabolic pathways as well as inflammatory signaling pathways. Some proteins, including succinate-CoA ligase subunit (Suclg1), NADH dehydrogenase subunit 5 (Nd5), NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 4-like 2 (Ndufa4l2) and cytochrome c oxidase assembly factor 7 (Coa7), which were closely related to mitochondrial respiratory electron transport, showed TMT dose and time dependent changes in the hippocampus of mice. Moreover, apoptotic molecules Bax and cleaved caspase-3 were up-regulated, while anti-apoptotic Bcl-2 was down-regulated compared with controls. In conclusion, our findings suggest that impairment of mitochondrial respiratory chain transport and promotion of apoptosis are the potential mechanisms of TMT induced hippocampus toxicity in mice.

Metamorphosis of a Commodity Plastic like PVC to Efficient Catalytic Single-Chain Nanoparticles.

We perform the conversion of a commodity plastic of common use in pipes, window frames, medical devices, flexible hoses, etc. like polyvinyl chloride (PVC) to single-chain nanoparticles (SCNPs). SCNPs are versatile, protein-mimetic soft nano-objects of growing interest for catalysis, sensing, and nanomedicine, among other uses. We demonstrate that the metamorphosis process -as induced through metal-free click chemistry- leads to well-defined, uniform SCNPs that are stable during storage in the solid state for months. All the conversion process (from PVC isolation to PVC-SCNPs synthesis) can be run in a green, dipolar aprotic solvent and involving, when required, a simple mixture of ethanol and water (1/1 vol.) as non-solvent. The resulting PVC-SCNPs are investigated as recyclable, metalloenzyme-mimetic catalysts for several representative Cu(II)-catalyzed organic reactions. The method could be valid for the metamorphosis and valorization of other commodity plastics in which it is feasible to install azide functional groups in their linear polymer chains.

Metamorphosis of a Commodity Plastic like PVC to Efficient Catalytic Single‐Chain Nanoparticles

AbstractWe perform the conversion of a commodity plastic of common use in pipes, window frames, medical devices, flexible hoses, etc. like polyvinyl chloride (PVC) to single‐chain nanoparticles (SCNPs). SCNPs are versatile, protein‐mimetic soft nano‐objects of growing interest for catalysis, sensing, and nanomedicine, among other uses. We demonstrate that the metamorphosis process ‐as induced through metal‐free click chemistry‐ leads to well‐defined, uniform SCNPs that are stable during storage in the solid state for months. All the conversion process (from PVC isolation to PVC‐SCNPs synthesis) can be run in a green, dipolar aprotic solvent and involving, when required, a simple mixture of ethanol and water (1/1 vol.) as non‐solvent. The resulting PVC‐SCNPs are investigated as recyclable, metalloenzyme‐mimetic catalysts for several representative Cu(II)‐catalyzed organic reactions. The method could be valid for the metamorphosis and valorization of other commodity plastics in which it is feasible to install azide functional groups in their linear polymer chains.