Vinyl Chloride Research Articles

Human Health Risk Assessment of Chlorinated Hydrocarbons in Groundwater Based on Multi-Pathway Analysis

The rapid development of the global chemical industry has led to widespread groundwater contamination, with frequent pollution incidents posing severe threats to water safety. However, there has been insufficient assessment of the health risks posed by chlorinated hydrocarbon contamination in groundwater around chemical industrial parks. This study evaluates the chlorinated hydrocarbon contamination in groundwater at a chemical park and conducts a multi-pathway health risk assessment, identifying the key risk pollutants. In addition, sensitivity analysis of the primary exposure pathways was performed using the Monte Carlo method. The results indicate severe exceedance of pollutant concentrations with widespread diffusion. Carcinogenic risks were mainly driven by vinyl chloride, whose oral cancer slope factor was significantly higher than that of other substances, while non-carcinogenic risks were dominated by trichloro-ethylene, which had the lowest reference dose. Both carcinogenic and non-carcinogenic risks through the drinking water pathway accounted for approximately 90% of the total risk, whereas the risk contribution from dermal contact was negligible. Although boiling water can partially reduce the risks, its effect on high-concentration pollutants is limited. Additionally, sensitivity analysis showed that pollutant concentration was the primary influencing factor for risk values, followed by exposure duration. The findings of this study provide a scientific basis for effectively formulating pollution control measures and ensuring the drinking water safety of nearby residents.

On the atmospheric budget of 1,2-dichloroethane and its impact on stratospheric chlorine and ozone (2002–2020)

Abstract. The chemical compound 1,2-dichloroethane (DCE), or ethylene dichloride, is an industrial very short-lived substance (VSLS) whose major use is as a feedstock in the production chain of polyvinyl chloride (PVC). Like other chlorinated VSLSs, transport of DCE (and/or its atmospheric oxidation products) to the stratosphere could contribute to ozone depletion there. However, despite annual production volumes greatly exceeding those of more prominent VSLSs (e.g. dichloromethane), global DCE observations are sparse; thus, the magnitude and distribution of DCE emissions and trends in its atmospheric abundance are poorly known. In this study, we performed an exploratory analysis of the global DCE budget between 2002 and 2020. Combining bottom-up data on annual production and assumptions around fugitive losses during production and feedstock use, we assessed the DCE source strength required to reproduce atmospheric DCE observations. We show that the TOMCAT/SLIMCAT 3-D chemical transport model (CTM) reproduces DCE measurements from various aircraft missions well, including HIPPO (2009–2011), ATom (2016–2018), and KORUS-AQ (2016), along with surface measurements from Southeast Asia, when assuming a regionally varying production emission factor in the range of 0.5 %–1.5 %. Our findings imply substantial fugitive losses of DCE and/or substantial emissive applications (e.g. solvent use) that are poorly reported. We estimate that DCE's global source increased by ∼ 45 % between 2002 (349 ± 61 Gg yr−1) and 2020 (505 ± 90 Gg yr−1), with its contribution to stratospheric chlorine increasing from 8.2 (± 1.5) to ∼ 12.9 (± 2.4) ppt Cl (where ppt denotes parts per trillion) over this period. DCE's relatively short overall tropospheric lifetime (∼ 83 d) limits, although does not preclude, its transport to the stratosphere, and we show that its impact on ozone is small at present. Annually averaged, DCE is estimated to have decreased ozone in the lower stratosphere by up to several parts per billion (< 1 %) in 2020, although a larger effect in the springtime Southern Hemisphere polar lower stratosphere is apparent (decreases of up to ∼ 1.3 %). Given strong potential for growth in DCE production tied to demand for PVC, ongoing measurements would be of benefit to monitor potential future increases in its atmospheric abundance and its contribution to ozone depletion.

Contrasting Kinetics of Highly Similar Chloroalkane Reductive Dehalogenases.

Chloroform and trichloroethanes are pervasive groundwater contaminants for which bioremediation has been an effective treatment strategy. Reductive dehalogenase (RDase) enzymes from organohalide-respiring bacteria are essential for their remediation under anaerobic conditions. RDases are responsible for dehalogenating these chlorinated solvents, leading to their removal. This work explores the kinetic characteristics of three closely related Dehalobacter chloroalkane-reductases─TmrA, CfrA, and AcdA─and identifies differences between their activity on chloroform (CF), 1,1,1-trichloroethane (TCA), and 1,1,2-TCA. The side-by-side comparison of these enzymes has emphasized that TmrA and AcdA are specialized toward CF with both having a 4-fold higher maximum specific activity (Vmax) on CF than 1,1,1-TCA, whereas CfrA has very similar rates on both CF and 1,1,1-TCA. AcdA is the most sensitive to substrate inhibition by CF and 1,1,2-TCA and inhibition by a common cocontaminant trichloroethene. Finally, the reduction of 1,1,2-TCA, which can produce both 1,2-dichloroethane and vinyl chloride, was assessed for each enzyme. Interestingly, each enzyme has a distinct preference for the major product it produces, indicating a favored reaction pathway. Despite over 95% sequence identity, TmrA, CfrA, and AcdA exhibit substantial differences in kinetic behavior, highlighting the importance of understanding such nuances for informed bioremediation strategies.

Isobaric Vapor–Liquid Equilibria for Separation of the n-Propanol and Water Azeotropic System with the Addition of a Choline Chloride–Ethylene Glycol-Based Deep Eutectic Solvent as an Entrainer

Isobaric Vapor–Liquid Equilibria for Separation of the <i>n</i>-Propanol and Water Azeotropic System with the Addition of a Choline Chloride–Ethylene Glycol-Based Deep Eutectic Solvent as an Entrainer

Engineering Cr−O−Ti structure towards boosted vinyl chloride destruction: Oxygen species evolution and reaction mechanism

Engineering Cr−O−Ti structure towards boosted vinyl chloride destruction: Oxygen species evolution and reaction mechanism

Ethyl chloride poisoning from inhalational misuse: clinical features and outcomes

Introduction Ethyl chloride misuse remains a prevailing concern due to its accessibility, but detailed descriptions of the features of toxicity are limited to sporadic reports, resulting in knowledge gaps in their clinical features and diagnosis. Objective To describe the clinical features, treatment, and outcomes of patients reported in the literature who developed toxicity from inhalational use of ethyl chloride. Methods We reviewed relevant literature over the past 50 years and analyzed the characteristics and outcomes of patients with toxicity from the inhalational use of ethyl chloride. Results A total of 21 studies from 1979 to 2024 were identified, making available 22 patients for analysis. Their median age was 40 years (range 16–62 years), and there were more than four times as many males as females. Ethyl chloride-containing cleaning solvents (8/22, 36%) were most commonly used. Regular inhalation of ethyl chloride was documented in approximately two-thirds of the patients (14/22, 66%), with a median duration of five months of misuse (range 2–360 months). A large proportion of patients (15/22, 68%) inhaled ethyl chloride again within a week from the onset of toxicity. Although features of cerebellar dysfunction were very common at presentation (13/16, 81%), abnormalities on neuroimaging studies were rare. Death occurred in more than a quarter of cases (6/22, 27%), with patients either already deceased or dying shortly after. Half (3/6) of these deaths were directly attributable to the development of lethal cardiac dysrhythmias. Conversely, most survivors either improved or fully recovered within a few days to weeks (14/16, 88%), independent of their presenting symptoms, clinical signs, and the treatments they received. Discussion Ethyl chloride users are likely young or middle-aged males, and clinical features of toxicity can range from transient neurological symptoms to cardiac dysrhythmias and death. The prominence of neurotoxicity may be attributed to the lipophilic nature of ethyl chloride and its tendency to accumulate in neural tissue, while cardiac dysrhythmias have been attributed to cardiac sensitization to catecholamines through ethyl chloride-induced inhibition of potassium, calcium, and sodium channels. Conclusions Toxicity from the inhalational misuse of ethyl chloride should be considered in young or middle-aged males presenting with acute cerebellar dysfunction. We recommend that suspected cases undergo telemetric monitoring for 24 h, especially when tachycardia and/or palpitations are present, as deaths from lethal cardiac dysrhythmias are not uncommon.

Gas check prevention during calendering of poly(vinyl chloride) films using poly(caprolactone)‐based additives

AbstractGas checks on poly(vinyl chloride) (PVC) calendered films are a common but not well understood surface quality defect that causes delays and resource wastage during the manufacturing of plastic sheets and films. Three modified poly(caprolactone) (PCL)‐based additives of differing molecular weights were used as a secondary plasticizer in PVC with the goal of preventing the formation of gas checks without modifying the calendering process conditions. To better understand gas check prevention processes, the effects of the PCL‐based additives on the thermal, mechanical, rheological, and chemical properties of PVC blends were assessed. A high molecular weight (2000 g/mol) PCL‐based additive was unable to prevent gas checks in PVC blends, unlike the lower molecular weight (540 g/mol and 900 g/mol) additives. Chemical and physicochemical properties affect the prevention or reduction of gas checks showing that the acid values and molecular weights of the PCL‐based additives are related to the number of gas checks. In contrast, physical properties, including rheological ones like complex viscosity or the storage and loss moduli that were previously hypothesized to be important factors in preventing gas check formation, were not significantly impacted by the addition of the secondary plasticizer. Furthermore, the acid value was observed to be related to the reduction in gas checks, likely due to the interaction of the dispersed functional acid groups with the entrapped air. Consequently, the effectiveness of the additive in eliminating gas checks declines as the acid value decreases.Highlights Low concentrations of PCL‐based additives prevent gas checks on PVC films. They do not significantly affect the physical/mechanical properties of films. Higher molecular weight additives are beneficial, but only below 2000 g/mol. The effectiveness of PCL‐based additives increases with acid value.

Poly(vinyl chloride) (PVC): an updated review of its properties, polymerization, modification, recycling, and applications

Poly(vinyl chloride) (PVC): an updated review of its properties, polymerization, modification, recycling, and applications

Molecular adsorption of chloromethane and vinyl chloride on square lattice net phosphorene – A first-principles study

The advancement of two-dimensional (2D) materials after the discovery of graphene leads to the path of various 2D materials. One such 2D material is square lattice (sql) net phosphorene. Initially, the structural and dynamic stability of sql phosphorene is confirmed with regard to the formation energy and phonon-band-spectrum. The electronic properties of sql phosphorene are explored using band structure and projected density of states spectrum. Besides, the calculated band gap value of sql phosphorene is 3.174 eV which shows the semiconducting nature of the material. Owing to the structural firmness and semiconducting nature of sql phosphorene material, it is used as a sensing element for chloromethane and vinyl chloride molecules. Evidently, the adsorption of chloromethane and vinyl chloride on sql phosphorene leads to modulating the energy band gap, electron difference density, and charge transfer, which infers changes in the electronic properties of sql phosphorene. The adsorption energy range is recorded to be −0.152 eV to −0.608 eV which confirms that the chloromethane and vinyl chloride are physisorbed on sql phosphorene. The findings ensure that sql phosphorene is a proper sensing element for the detection of chloromethane and vinyl chloride molecules.

Enhancing mechanical and thermal properties of rigid poly(vinyl chloride) composites via stearic acid‐treated zinc oxide filler

Enhancing mechanical and thermal properties of rigid poly(vinyl chloride) composites via stearic acid‐treated zinc oxide filler

Use of carbon-14 labeled trichloroethene to assess degradation potential in rock core microcosms

In fractured rock aquifers contaminated with trichloroethene (TCE), the extent of groundwater plumes is impacted by degradation occurring within the rock matrix. The objective of this study was to evaluate TCE degradation in rock samples from three sites where in situ conditions may favor natural or enhanced attenuation. Intact rock core microcosms (94 total) were used to assess in situ conditions and enhancement by addition of lactate or lactate + sulfate. A key advance for this study was inclusion of carbon-14 (14C) labeled TCE in the experimental design, which enables monitoring of 14C-labeled products in addition to more readily detectable compounds associated with TCE degradation (i.e., cis-1,2-dichloroethene (cDCE), vinyl chloride, acetylene, ethene, and ethane). 14C-labeled products comprised 35–95 % of the total degradation products recovered over 9–21 months of monitoring, indicating that inclusion of 14C-TCE was essential to capturing the full potential for abiotic and biotic degradation of TCE. Microcosms infused with TCE but not 14C-TCE exhibited enrichment in δ13C-TCE, and enrichment in δ13C-cDCE in microcosms that underwent reductive dechlorination of TCE to cDCE. The results demonstrate the advantages of using diffusion-transport microcosms and 14C-TCE to document degradation of chlorinated ethenes in fractured rock aquifers.

Aging Dynamics of Polyvinyl Chloride Microplastics in Three Soils with Different Properties.

Microplastic (MP) contamination in soil has been of great concern, but the dynamic aging process and potential pathways of MPs in natural soil systems remain poorly understood. Herein, poly(vinyl chloride) microplastics (5% w/w) were weathered for 12 months in sandy soil, silty clay, and silt loam. The results showed that the continuous increase of C═O and O-H groups (rate constant, k = 0.080-0.424 m-1) with time was observed on the surface of MPs aging in sandy soil due to the leading role of •OH induced by light irradiation. In the loam soil, the abundant coating of aluminosilicates and iron oxides on the MP surface by the formation of mineral-hydroxyl groups inhibited the generation of the C═O group (k < 0.165 m-1). The k of the characteristic bond C-Cl during the first 9 months was 9.51 and 1.93 times higher in clay compared to that in sandy and loam soil, respectively, revealing that dechlorination triggered the first step of the aging process for MPs in clay owing to the participation of degrading bacteria (Phenylobacterium and Caulobacteraceae). The results provide important insights into the aging dynamics of MPs in environmentally realistic circumstance, which account for understanding the different aging processes of MPs in different soils.

Synergistic effect of Ca/Zn main stabilizer and maltitol auxiliary stabilizer on the thermal stability, mechanical properties, and transparency of poly(vinyl chloride)

AbstractMaltitol, a natural compound, offers a potentially eco‐friendly alternative to conventional auxiliary thermal stabilizers. Its auxiliary stabilization effect was studied by discoloration tests, Congo red tests, thermogravimetric analysis, and UV–visible spectroscopy. Additionally, x‐ray photoelectron spectroscopy and discoloration tests were used to study the stabilizing mechanisms of maltitol. Compared to dipentaerythritol, commonly used in the PVC industry, maltitol as an auxiliary stabilizer exhibits better improvement in thermal stability. This improvement is related to its melting point, ability to complex with zinc chloride, and content of hydroxyl groups. Furthermore, the addition of maltitol in PVC not only maintains good transparency of PVC basically unchanged but also improves the mechanical properties. Maltitol, as a natural, eco‐friendly, and efficient auxiliary thermal stabilizer, exhibits a promising application prospect in PVC materials.

Soft Artificial Muscle of Poly(vinyl chloride) Gel with an Imperceptible Liquid Metal Electrode.

Electrodes with high electrical conductivity, yet good flexibility and mechanical compliance, are critical for electroactive artificial muscles. Herein, a promising liquid metal (LM) electrode is proposed by transforming eutectic gallium-indium (EGaIn) LM with high surface tension into paste-like LM with solid Ga2O3 shells. The developed compliant LM electrode not only shows high conductivity and negligible additional stiffness but also displays excellent electrical stability during cyclic actuation. Based on the LM electrode, the poly(vinyl chloride) gel (PVCG) artificial muscle developed exhibits the maximum actuation strain of 18.7% at a low electric field strength of 9 V μm-1 and maintains excellent durability without obvious performance attenuation after 10,000 s. A comparison shows that the as-developed PVCG artificial muscle is superior over that based on widely used carbon electrodes. Moreover, an artificial upper limb and crawling worm were manufactured to explore the great potential of PVCG artificial muscle in the robotic field. In addition, the practical application demonstration of the PVCG artificial muscle in the biomimetics field is also successfully fulfilled through the design of reasonable structures. Due to its easy fabrication, excellent electrical conductivity, and high mechanical compliance, the newly developed LM electrode is promising for high-performance PVCG artificial muscles in bionic robots.

Influence of halloysite nanotubes on processing, structural and thermal properties of poly(vinyl chloride)/high-density polyethylene composites with wood flour

ABSTRACT The aim of this work was to investigate the effect of halloysite nanotubes (HNT) on the processing, structural and thermal properties of poly(vinyl chloride) (PVC), high-density polyethylene (HDPE), and PVC–HDPE composites with various proportions of both polymer components containing 30 wt% wood flour (WF) and 5 wt% halloysite processed in the Brabender measuring mixer. The HNT content in the composites leads to a slight increase in the maximum torque and a reduction in the gelation time for PVC and PVC–HDPE matrix composites with the 90:10 component ratio. In addition, microscopic images of these materials showed a homogeneous distribution of HNT in the polymer matrix. The addition of mineral filler to the matrix, regardless of the polymer type, resulted in a slight increase in the torque values at the kneading endpoint. The PVC–HDPE–wood flour composites are characterized by higher thermal stability at processing temperature when HNT is loaded. The introduction of 5 wt% HNT into the PVC–HDPE 90:10 30 wt% WF blend resulted in an increase of the 2% weight loss temperature by 16°C. The simultaneous use of wood flour and halloysite as fillers for PVC–HDPE blends could be an eco-efficient solution for the new composite material sector.

Iron-Catalyzed Synthesis of Ferrocenyl–Thioether Conjugates via C–S Cross-Coupling of Thioethers and Vinylic Chlorides: Construction, Anticancer, and Computational Studies

Iron-Catalyzed Synthesis of Ferrocenyl–Thioether Conjugates via C–S Cross-Coupling of Thioethers and Vinylic Chlorides: Construction, Anticancer, and Computational Studies

Synthesis of phosphorus-containing modifier based on phenolic epoxy resin and its application in flexible poly(vinyl chloride)/magnesium hydroxide composites

In this study, a phosphorus-containing and polyether structure modifier, phenolic epoxy phosphate ester (PEPE), was prepared by the reaction of phenolic epoxy resin (EPN) and phosphoric acid. It was used to solve the trade-off dilemma of simultaneously improving the mechanical properties and flame resistance of flexible poly (vinyl chloride) (fPVC)/magnesium hydroxide (MH) composites. The peak heat release rate, total heat release, peak smoke production rate, and total smoke production of the fPVC/MHPEPE-5 (PEPE modified MH as filler) composite were decreased by 35.31 %, 49.2 %, 40.42 %, and 27.26 %, respectively, in comparison with the fPVC/MH composite. More importantly, the fPVC/MHPEPE-5 composite passed V-0 rating in the UL-94 test, while the fPVC and fPVC/MH composite passed V-2 and V-1 rating. The presence of phosphorus compounds in the condensed phase promoted the formation of a dense char residue of the fPVC/MHPEPE-5 composite. Therefore, the heat and flammable volatiles cannot migrate between the substrate zone and the combustion zone. In the gas phase, the dilution effect of H2O reduced the concentration of oxygen and combustible volatiles. The radicals quenching effect of the primary and secondary pyrolysis products of PEPE (such as PO· and PO2·) with ·H and ·OH. radicals played a crucial role in flame extinguishing and combustion termination. In addition, the scanning electron microscopy results showed that MHPEPE performed good compatibility with the fPVC matrix. The tensile and impact strength of the fPVC/MHPEPE-5 composite was 12.19 % and 19.26 % higher than that of the fPVC/MH composite, respectively.

Passerini and thiol-ene reactions: A facile, green, and efficient route to high-performance bio-based plasticizers

The increasing global demand for sustainable alternatives to petroleum-based plasticizers, particularly in poly(vinyl chloride) (PVC) products, has intensified the exploration of bio-based options derived from renewable resources such as plant oils. Traditional bio-based plasticizers, while promising, often suffer from limitations such as low molecular weight, high volatility, and poor compatibility with PVC, thereby restricting their practical applications. To surmount this hurdle, we introduce a novel synthetic route combining the Passerini reaction with the thiol-ene click reaction, aimed at producing high-performance plant oil-based plasticizers (POPs) with enhanced ester content and molecular weight. This method offers significant advantages over traditional methods, including low reaction temperatures (≤40 ​°C), ultrahigh yield (95 ​%) when using ethanol as the solvent, and precise control over ester content. Furthermore, the key findings demonstrate that the designed and synthesized POP (bio-content, 69 ​%) produced using this method exhibits outstanding overall performance, such as excellent migration resistance, good compatibility with PVC, and high thermal stability compared to traditional plasticizers. This facile, green, and efficient method may significantly advance the adoption of bio-based plasticizers, establishing them as a viable alternative to petroleum-based counterparts.

Dry Transfer of van der Waals Junctions of Two-Dimensional Materials onto Patterned Substrates Using Plasticized Poly(vinyl chloride)/Kamaboko-Shaped Polydimethylsiloxane.

Two-dimensional (2D) materials can be transferred onto substrates with various surface structures, opening up multiple functions and applications for 2D materials in the form of suspended membranes. In this paper, we present a method for transferring exfoliated 2D crystal flakes from SiO2 substrates onto patterned substrates using a poly(vinyl chloride) (PVC) layer mounted on a polydimethylsiloxane (PDMS) stamp structure. 2D crystal flakes can be transferred onto various patterned structures such as grooves, round holes, and periodic hole or groove patterns. Our method can also be used to fabricate suspended van der Waals (vdW) heterostructures by assembling 2D crystal flakes on the PVC/PDMS stamp and then transferring them onto patterned substrates. The adhesiveness and curvature of the PVC/PDMS stamp were tuned, and a high successful transfer rate was realized due to the use of kamaboko-shaped (semicylindrical) PDMS and the addition of an appropriate amount of a high-viscosity plasticizer to the PVC layer. Taking advantage of this method, we demonstrate the facile fabrication, simply by transferring a vdW heterostructure onto an Au-coated groove substrate, of a suspended vdW field-effect transistor device with the carrier density tuned using ionic gating. This method enables the transfer of 2D crystal flakes and vdW heterostructures onto various patterned substrates, and hence it should help to advance suspended 2D materials research.

In- vitro evaluation of blood bags based on poly(vinyl chloride)/ selenium nanocomposites and exposed to electron beam irradiation

In- vitro evaluation of blood bags based on poly(vinyl chloride)/ selenium nanocomposites and exposed to electron beam irradiation