Vinyl Chloride Research Articles

Electrochemical low valent cobalt-catalyzed addition of aryl and vinyl chlorides to α-ketoamides via C-Cl bond activation.

The development of an electrochemical cobalt catalyzed C-Cl bond activation at room temperature for the nucleophilic addition of aryl and vinyl chlorides to α-ketoamides is described. The overall method operates through an electrochemically induced low valent cobalt catalyst that oxidatively adds to aryl or vinyl chlorides affording medicinally important 3-hydroxy oxindole and 3-hydroxypyrrolidinone scaffolds. The development of an enantioselective version using a chiral pyrox ligand is also demonstrated.

Synthesis of tunable thickness-to-diameter ratio microcapsules via a diffusion-controlled process for temperature-responsive release.

Designing microcapsules with a complicated functionalized shell to respond to an external stimulus has attracted much attention for triggered release; however, simplifying the synthesis process remains a significant challenge. Herein, we initially propose a novel, simple synthesis strategy that utilizes a mixed solvent as the organic phase to control the diffusion of common monomers during interfacial polymerization, resulting in the successful preparation of microcapsules with tunable thickness-to-diameter ratios (T/D). The morphology of microcapsules is confirmed by scanning electron microscopy. We also observe that the T/D of the designed microcapsules progressively increases as the diffusion of monomers occurs, and the glass transition temperature of microcapsules is controlled. Furthermore, microcapsule-based crosslinking agents are applied to investigate the crosslinking reaction of poly(vinyl chloride). Rotational rheometer results indicate that the microcapsules exhibit an excellent external stimulus response, precisely triggering release at the predetermined temperature. This simple approach for the preparation of microcapsules with tunable physical properties has great potential for triggered release in diverse applications.

High-performance transparent hybrid (ionic and dielectric) gel actuator system based on poly(vinyl chloride)/dibutyl adipate/ionic liquid gels operating at a low applied voltage

This study presents a transparent hybrid (ionic and dielectric) gel actuator system based on polyvinyl chloride (PVC) and ionic liquid (IL) gels with dibutyl adipate (DBA) as the plasticiser.

Excellent dielectric energy storage performance achieved by synergistically increasing the permittivity and breakdown strength of poly(vinylidene chloride-co-vinyl chloride) with a stabilized conformation

The increased conformational barrier endows P(VDC-VC) with superior dielectric energy storage performance.

Novel environmentally sustainable plasticizers based on ricinoleic acid for polyvinyl chloride: structure and properties

Two environmentally friendly plasticizers with different structures were synthesized based on ricinoleic acid from non-food crop sources with good plasticizing effect, migration, and volatility resistance.

The role of absorption mechanism on the optimization of processing commercial polymers under high repetition rate femtosecond laser irradiation

The response of three of the most used commercial polymers (poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET) and polypropylene (PP)) under irradiation with high repetition rate (1 kHz–1 MHz) femtosecond (450 fs) multi-pulse (N = 10–1500) laser at λ = 343 nm, 515 nm (1.40 J/cm2 for both former wavelengths) and 1030 nm (1.70 J/cm2) is reported, obtaining a study on how the absorption mechanism influences the processing efficiency for these materials. Tunable ablation depth and diameters are accomplished by modifying repetition rates at a constant fluence and number of pulses. The results highlight the role of absorption mechanism, repetition rate ranges and thermal properties of the materials for benefiting ablation efficiency. Furthermore, the use of high repetition rates improves the laser processing, reducing extended thermal effects and increasing ablation uniformity.

Theoretical investigation of the OH-initiated atmospheric degradation mechanism of CX2CHX (X = H, F, Cl) by advanced quantum chemical and transition state theory methods.

Halogenated olefins are anthropogenic compounds with many industrial applications but at the same time raising many environmental and health concerns. Gas-phase electrophilic addition of the OH radical to the olefinic CC bond represents the primary sink for these chemicals in the atmosphere, with the degree and type of halogenation playing a significant role in their overall reactivity. In this work, we present a theoretical investigation of the reaction mechanisms and kinetics for the reactions between the OH radical and CH2CH2 (ethylene, ETH), CF2CHF (trifluoroethylene, TFE) and CCl2CHCl (trichloroethylene, TCE), simulated by state-of-the-art protocols and methods, with the aim of providing a detailed interpretation of the available experimental results, as well as new data of relevance to tropospheric chemistry. Specifically, potential energy surfaces (PESs) are obtained using the jun-Cheap (jChS) composite scheme, whereas temperature and pressure dependent rate coefficients and product distributions in the 100-600 K temperature range are calculated within the Rice-Ramsperger-Kassel-Marcus/master equation (RRKM/ME) framework. The rates for barrierless channels are obtained from variable reaction coordinate-variational transition state theory (VRC-VTST) combined with the two transition state model. While the reactions with ETH and TFE proceed mainly via the formation of addition adducts at P = 1 atm and T = 298 K, the dominant channel for TCE is the Cl-elimination reaction. Global rate constants for the two halogenated olefins, TFE and TCE, are found to be pressure-independent, contrary to the case of ETH. The computed rate constants, as well as their temperature and pressure dependence, are in remarkable agreement with the available experimental data, and they are used to derive atmospheric lifetimes (τ) for both TFE and TCE as a function of altitude (h) in the atmosphere, by taking into account variations in the rate coefficients (k (T, P)) and [OH] concentration.

Progress in mercury-free catalysts for acetylene hydrochlorination

Developing mercury-free catalysts for efficient acetylene hydrochlorination to produce vinyl chloride monomer is crucial for the environment, human health and sustainability.

Significance of Volatile Organic Compounds to Secondary Pollution Formation and Health Risks Observed during a Summer Campaign in an Industrial Urban Area.

The chemical complexity and toxicity of volatile organic compounds (VOCs) are primarily encountered through intensive anthropogenic emissions in suburban areas. Here, pollution characteristics, impacts on secondary pollution formation, and health risks were investigated through continuous in-field measurements from 1-30 June 2020 in suburban Nanjing, adjacent to national petrochemical industrial parks in China. On average, the total VOCs concentration was 34.47 ± 16.08 ppb, which was comprised mostly by alkanes (41.8%) and halogenated hydrocarbons (29.4%). In contrast, aromatics (17.4%) dominated the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) with 59.6% and 58.3%, respectively. Approximately 63.5% of VOCs were emitted from the petrochemical industry and from solvent usage based on source apportionment results, followed by biogenic emissions of 22.3% and vehicle emissions of 14.2%. Of the observed 46 VOC species, hexachlorobutadiene, dibromoethane, butadiene, tetrachloroethane, and vinyl chloride contributed as high as 98.8% of total carcinogenic risk, a large fraction of which was ascribed to the high-level emissions during ozone pollution episodes and nighttime. Therefore, the mitigation of VOC emissions from petrochemical industries would be an effective way to reduce secondary pollution and potential health risks in conurbation areas.

Effect of Cu modification to Ru/HZSM-5 catalysts on the catalytic combustion of vinyl chloride

The redox capacity of Ru–2Cu/HZSM-5 catalyst is improved by Cu modification, resulting in increased activity for catalytic combustion of VC.

Beyond Plastics on pyrolysis moratorium, packaging reduction and banning vinyl chloride and PVC

On January 3, 2024, Beyond Plastics reported that the city of Youngstown, Ohio, has adopted a one-year moratorium on pyrolysis or gasification or combustion of tires, chipped tires, plastics, and electronic waste in the city of Youngstown, Ohio. The city council voted unanimously on December 20, 2023; Mayor Jamael Tito Brown signed the bill on December 26, 2023; and it went into effect immediately on December 26, 2023.

Visible light-induced halogen-atom transfer by N-heterocyclic carbene-ligated boryl radicals for diastereoselective C(sp3)-C(sp2) bond formation.

Photoinduced halogen-atom transfer (XAT) has rapidly emerged as a programmable approach to generate carbon-centered radical intermediates, mainly relying on silyl and α-aminoalkyl radicals as halogen abstractors. More recently, ligated boryl radicals have also been proposed as effective halogen abstractors under visible-light irradiation. In this study, we describe the use of this approach to enable C(sp3)-C(sp2) bond formation via radical addition of carbon-centered radicals generated via XAT onto chloroalkynes. Our mechanistic investigation reveals a complex interplay of highly reactive radical intermediates which, under optimized conditions, delivered the targeted vinyl chlorides in excellent yields and Z : E ratios. Finally, we demonstrated the synthetic value of these products in transition metal-based cross-coupling reactions.

THERMAL DEGRADATION OF POLY(VINYL CHLORIDE)/POLYSTYRENE BLENDS IN THE PRESENCE OF DERIVATIVES OF Hura crepitans SEED OIl.

Poly(vinyl chloride) (PVC) is a versatile polymer that has found applications in various sphere of our daily life. However, it is intrinsically unstable at elevated temperatures usually employed in processing it into useful articles. The thermal stability of poly(vinyl chloride) (PVC) has been reported to improve in a blend with polystyrene (PS) and compatibility of the polymers was a factor which influenced the stabilization process. There has been no report of thermal stability of PVC/PS blends in the presence metal soap of seed oil. In this study, the thermal degradation of poly(vinyl chloride)/polystyrene (PVC/PS) blends in the absence and presence of metal soaps of Hura crepitans seed oil (HCSO) has been investigated in air and under nitrogen atmosphere. Metal soaps of Hura crepitans seed oil; Al, Ba, Ca, Mg and Zn were prepared by precipitation method involving metathesis in alcohol. Kinetics of thermal degradation of PVC and the blends were carried out titrimetrically in the temperature range 170-190 oC under nitrogen atmosphere. The interaction of the additives with PVC was studied with FTIR spectrophotometer while the melt properties of PVC and the blends were determined using differential scanning calorimeter. The thermal stability study of the polymer and the blends was carried with thermogravimetric analyzer under nitrogen and air atmospheres. In the absence of metal soaps, the kinetics of thermal degradation of PVC in PVC/PS blends, 95/5, and 90/10 ratios, measured titrimetrically under nitrogen atmosphere in the temperature range 170- 190 oC, was determined by the rates of dehydrochlorination of the polymer. The rates of dehydrochlorination were of the order, 10-2 %min-1 and showed stabilization of PVC by PS in the blends. Specifically, at 190 oC, the rates of dehydrochlorination of PVC under nitrogen atmosphere were reduced by 23.7 and 11.2% for the 95/5 and 90/10 blends respectively with calculated activation energy of 50.7kJ mol-1for the process. In the presence of HCSO soaps of Al, Ba, Ca, Mg and Zn, there were marked reductions in stabilization of PVC by PS and were associated with increased polarity of the blends. Miscibility of the blends was enhanced by the soaps, as was evident from FTIR and DSC analyses, showing from the latter, single Tgs of 98.2 and 96.2 oC for 95/5 and 90/10 blends respectively. The enhanced stability of PVC in the blends by PS and reduced stability of the polymer in the presence of metal soaps were confirmed by thermogravimetry. PS enhanced thermal stability of PVC in PVC/PS blends while the presence of metal soaps of Hura crepitans seed oil in PVC/PS blends is antithetical to thermal stability of PVC.

Risks Associated with the Presence of Polyvinyl Chloride in the Environment and Methods for Its Disposal and Utilization.

Plastics have recently become an indispensable part of everyone's daily life due to their versatility, durability, light weight, and low production costs. The increasing production and use of plastics poses great environmental problems due to their incomplete utilization, a very long period of biodegradation, and a negative impact on living organisms. Decomposing plastics lead to the formation of microplastics, which accumulate in the environment and living organisms, becoming part of the food chain. The contamination of soils and water with poly(vinyl chloride) (PVC) seriously threatens ecosystems around the world. Their durability and low weight make microplastic particles easily transported through water or air, ending up in the soil. Thus, the problem of microplastic pollution affects the entire ecosystem. Since microplastics are commonly found in both drinking and bottled water, humans are also exposed to their harmful effects. Because of existing risks associated with the PVC microplastic contamination of the ecosystem, intensive research is underway to develop methods to clean and remove it from the environment. The pollution of the environment with plastic, and especially microplastic, results in the reduction of both water and soil resources used for agricultural and utility purposes. This review provides an overview of PVC's environmental impact and its disposal options.

Acrylonitrile‐styrene‐acrylate particles with different acrylonitrile contents for improving the toughness of poly(vinyl chloride) resin

AbstractPoly(butyl acrylate) grafted styrene and acrylonitrile copolymer (PBA‐g‐SAN, ASA) with core–shell structures were prepared by emulsion polymerization technology to improve the toughness of the poly(vinyl chloride) (PVC). The mechanical properties of the PVC/ASA blends were investigated. The notch impact strength of the PVC/ASA blend could reach 1200 J/m when the 13 phr ASA was added to the PVC. This was several times more than pure PVC resin. Scanning electron microscopy analysis results indicated that the improvement in impact strength of the PVC/ASA blend was attributed to shear yielding induced by ASA particles. Additionally, subtle changes in the ratio of monomers in the shell layer led to significant fluctuations in the mechanical properties of the composites. Dynamic mechanical analysis showed that the intermolecular interaction forces between ASA particles and PVC resins played a key role in improving the toughness of PVC/ASA blend.

Effects of Apigenin and Apigenin- Loaded Nanogel on Induction of Apoptosis in Human Chronic Myeloid Leukemia Cells

Background: Diet plays an important role in cancer prevention. Apigenin, a flavonoid with thechemical formula C15H10O5, is abundantly present in vegetables. Vegetarian foods containing flavonoids are rich sources of bioactive compounds. Flavonoids have been utilized in herbal treatment. Nanogels are drug delivery systems based on polymers and are used in tissue engineering and for drug delivery. This study was conducted to compare the effects of apigenin and a nanodrug on the viability of the K562 cell line of chronic myeloid leukemia at different durations under laboratory conditions. Materials and Methods: Chitosan was first dissolved in 1% acetic acid, and ethylene dichloride EDC and NHS were added to the solution. Then, the nanodrug was prepared by loading apigenin into stearate–chitosan nanogel (scs nanogel), and its physical and morphological characteristics were evaluated by TEM, DLS, and FTIR. Trypan blue staining, MTT assay, and flow cytometry were used to analyze the effects of various concentrations of apigenin and apigenin-loaded chitosan–stearate nanogel (APG–SCS) at 24, 48, and 72 h after they were applied to the K562 cell line. Results: The diameter of the nanodrug particles was measured using DLS and confirmed by TEM. The K562 cells treated with APG–SCS and with apigenin exhibited significant differences compared with the control (P < 0.05). Apoptosis was detected by flow cytometry. Conclusion: This study showed that the toxic effects of apigenin and the nanodrug improved with increasing concentrations and exposure durations compared to those in the control.The toxic effect of apigenin loaded into the stearate-chitosan nanogel was greater than apigenin, and the toxic effects of both materials were greater compared to the control under laboratory conditions.[GMJ.2018;7:e1008]

Copolymerization of Industrial Organochlorine Waste with Wood Pyrolysis Products for Bitumen Compositions

The work presents a new approach to the copolymerization and co-processing of industrial organochlorine waste (OCW) resulted in the production of vinyl chloride at Karpatnaftochim LLC, Kalush, Ukraine, and liquid wood pyrolysis products (LWPP) generated by the activated charcoal production at Perechyn Forestry and Chemical Plant, LLC. Kalush, Ukraine. This article highlights studies of the composition of the raw materials and the properties of the resulting products. Through the use of infrared spectroscopy and DTA analysis, the primary structure and properties of copolymers, oligomers, asphalt and bitumen products obtained from OCW and LWPP were determined. It describes the trial of the liquid products of wood pyrolysis in bitumen compositions with OCW.

Biopolymer-Based Protective Layer for Stable and Highly Reversible Zinc Metal Anodes

Zinc (Zn) metal has attracted considerable attention because of its natural abundance and stability in aqueous environments compared with lithium/sodium metal anodes. Moreover, Zn metal as anode showed a high theoretical capacity (820 mAh g−1), high energy per volume (5855 mA cm−3), and low operational potential (–0.78 V vs SHE) in electrochemical systems. However, Zn metal suffers from dendrite growth and poor plating/stripping reversibility, resulting from inhomogeneous Zn ion flux and contamination by generally used glass fiber membranes (GFs) as separators. Although studies to inhibit dendritic Zn growth have been conducted, dendritic Zn remains still a major problem during long-term cycling under practical rate and capacity conditions. In this context, it is essential to investigate Zn deposition behavior from initial nucleation to Zn growth morphologies after long-term cycling.Among the problematic factors pointed out by researchers, the irregular pore distribution of GFs causes uneven Zn ion flux. Moreover, the detached fibers after cycling contaminate the Zn anode surface, resulting in nonuniform Zn deposition and trapping of Zn metal in the separator. To stabilize Zn metal anodes, introducing a protective layer can be an effective strategy to construct ion channels with abundant functional groups for high affinity with Zn metaland protect from direct contact with GFs. Organic polymers are suitable candidates for construction of protective layer which tolerates the volume changes of Zn metal and exhibit good chemical compatibility with Zn metal.Polysaccharides are favorable for use as gel polymers, separators, and binders owing to their cost-effectiveness and good electrochemical properties. Besides, they contain various oxygen-containing groups, resulting in relatively high ionic conductivity. However, it is not sufficient to fabricate membranes for the stabilization of Zn metal using polysaccharide alone because of insufficient ion conductive properties. This problem can be solved by blending polymers with high ionic conductivities such as poly(ethylene oxide) (PEO), poly(vinylidene difluoride), and poly(vinyl chloride). Notably, PEO has mainly been used in gel polymer electrolytes. The hydroxyl groups of PEO can facilitate the transport of metal ions and ether linkages can enhance the affinity with cations, resulting high ionic conductivity.In this study, we designed a functional protective layer by blending polysaccharide and PEO and investigated Zn deposition behavior from the formation of initial nucleation to Zn growth process after long-term cycling. The protective layer, fabricated by a one-pot method, featured highly dispersed blending polymers by phase separation and contained uniformly distributed oxygen-containing functional groups. Moreover, we demonstrated that the protective layer induced the formation of regular Zn nucleation sites and smooth Zn deposition after long-term cycling under the realistic conditions required for high-energy metal battery systems. Using the Zn||Cu and Zn||Zn cells stabilized by the protective layer under low capacity (0.1 mAh cm−2), we confirmed that homogeneous initial Zn deposition patterns were induced by ex situ SEM images of Cu and Zn electrodes. Subsequently, smooth and dense Zn growth was confirmed under fast Zn plating/stripping conditions, indicating that protective layer can induce basal plane (002) dominant deposition to mitigate dendrite formation and protect physically and chemically from GFs.Based on the morphological Zn deposition behavior, we successfully fabricated a functional protective layer and significantly enhanced the electrochemical performance of Zn metal battery systems. The Zn||Cu cells with a functional protective layer showed significantly increased long-term cycling above 3850 cycles (more than 160 days) at high rate and capacity condition (2 mA cm−2 and 1 mAh cm−2). In addition, the durability of protective layer was confirmed by a high-rate test (at 10 mA cm−2). These results are consistent with those of the Zn||Zn symmetric cell tests under harsh conditions of 5 mA cm−2 and 5 mAh cm−2. Furthermore, full cell with the protective layer using vanadium disulfides as the cathode exhibited enhanced cyclability over 1000 cycles with 87 % capacity retention compared to the bare full cell that short-circuited at the 340th cycle.Our work demonstrated that there are two important factors affecting the durability of Zn anodes: (i) Zn metal surface should be protected by a smooth and dense layer with high affinity to Zn metal and ions and (ii) physical and chemical contamination from GFs. Figure 1

Effects of Copper(II) Oxide on the Co-Pyrolysis of Waste Polyester Enameled Wires and Poly(vinyl chloride).

The emission of chlorinated pollutants is one of the main problems when recovering copper (Cu) via pyrolysis from waste enameled wires. This is mainly attributed to other wastes which possess high poly(vinyl chloride) content, such as electrical wires and cables, which are often recycled together with enameled copper wires. In this research, to control the chlorinated pollutants, copper(II) oxide (CuO) was chosen and demonstrated to be an efficient dechlorinating agent, and CuO did not introduce any impurities that influence the quality of the recovered Cu. The pyrolysis and co-pyrolysis of polyester enameled wires, PVC, and CuO were investigated, and special attention was paid to chlorinated compounds in released pyrolytic products. In particular, the co-pyrolysis of this ternary mixture was studied for the first time, and some new pyrolysis behaviors were discovered. For example, the results of Py-GC/MS analyses showed that the addition of CuO removed about 75% of the chloro-organic products, the main types of which were chloroaromatic compounds rather than the more toxic chloroesters. Moreover, pyrolysis gases were collected and characterized via ion chromatography, and the results showed that the chlorine content in the pyrolysis gases decreased by about 71%. TG analysis indicated that CuO only minimally affected the pyrolysis of polyester paint. However, through the chlorine fixation effect, CuO influenced the dechlorination and dehydrochlorination of PVC, as well as secondary reactions between HCl and pyrolysis products of polyester paint, therefore changing the products and behaviors of co-pyrolysis. Mechanism of reducing chlorine-containing pollutants and reaction mechanism of forming typical pyrolysis products closely correlated to the effects of CuO were also proposed, providing theoretical guidance for the recycling of waste enameled wires.

Rapid Assessment of Di(2-ethylhexyl) Phthalate Migration from Consumer PVC Products.

Poly(vinyl chloride) (PVC) is widely used to produce various consumer goods, including food packaging, toys for children, building materials, and cosmetic products. However, despite their widespread use, phthalate plasticizers have been identified as endocrine disruptors, which cause adverse health effects, thus leading to increasing concerns regarding their migration from PVC products to the environment. This study proposed a method for rapidly measuring the migration of phthalates, particularly di(2-ethylhexyl) phthalate (DEHP), from PVC products to commonly encountered liquids. The release of DEHP under various conditions, including exposure to aqueous and organic solvents, different temperatures, and household microwaves, was investigated. The amount of DEHP released from both laboratory-produced PVC films and commercially available PVC products was measured to elucidate the potential risks associated with its real-world applications. Furthermore, tests were performed to evaluate cytotoxicity using estrogen-dependent and -independent cancer cell lines. The results revealed a dose-dependent impact on estrogen-dependent cells, thus emphasizing the potential health implications of phthalate release. This comprehensive study provides valuable insights into the migration patterns of DEHP from PVC products and forms a basis for further research on the safety of PVC and plasticizers.