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Materials (Basel, Switzerland) Nov 2020The traditional methods for preparing magnesium aluminum layered double hydrotalcite (MgAl-COLDHs) in industry include coprecipitation and hydrothermal methods. Both...
The traditional methods for preparing magnesium aluminum layered double hydrotalcite (MgAl-COLDHs) in industry include coprecipitation and hydrothermal methods. Both these methods have the disadvantages of high preparation cost and complicated water washing process. Using Mg(OH), Al(OH), and CO as raw materials in this work, the MgAl-CO LDHs are successfully prepared by mechanochemical method, which solves the shortcomings of traditional preparation method and realizes the conversion and utilization of CO resource. The prepared MgAl-CO LDHs are evaluated as a heat stabilizer in poly(vinyl chloride) (PVC). The result indicates that, when 2.4 phr MgAl-CO LDHs, 0.3 phr ZnSt, and 0.3 phr of zinc acetylacetonate are added to the PVC, the thermal stability time of PVC can reach 190 min, which is better than PVC containing commercial MgAl-CO LDHs. Meanwhile, its processing performance is basically the same as the PVC containing commercial MgAl-CO LDHs.
PubMed: 33227994
DOI: 10.3390/ma13225223 -
Materials (Basel, Switzerland) Oct 2018A simple approach to decorate multi-walled carbon nanotube (MWCNT)⁻reduced graphene oxide (RGO) hybrid nanoparticles with zinc oxide (ZnO) nanorods is developed to...
A simple approach to decorate multi-walled carbon nanotube (MWCNT)⁻reduced graphene oxide (RGO) hybrid nanoparticles with zinc oxide (ZnO) nanorods is developed to improve the electrical and mechanical properties of poly(vinyl chloride) (PVC)/MWCNT⁻RGO composites. The ZnO nanorods act as "joint" in three-dimensional (3D) MWCNT⁻RGO networks and the hybrid particles strongly interact with PVC chains via p-π stacking, hydrogen bonds, and electrostatic interactions, which we confirmed by scanning electron microscopy (SEM) and Raman analysis. By introducing the ZnO nanorods, the RGO⁻ZnO⁻MWCNT hybrid particles increased 160% in capacitance compared with MWCNT⁻RGO hybrids. Moreover, the addition of RGO⁻ZnO⁻MWCNT to PVC resulted in the mechanical properties of PVC being enhanced by 30.8% for tensile strength and 60.9% for Young's modulus at the loadings of 2.0 weight percent (wt.%) and 1.0 wt.%, respectively. Meanwhile, the electrical conductivity of PVC increased by 11 orders of magnitude, from 1 × 10 S/m to 1 × 10 S/m for MWCNT⁻ZnO⁻RGO loading at 5.0 wt.%.
PubMed: 30380755
DOI: 10.3390/ma11112139 -
International Journal of Occupational... Dec 2013
Topics: Alcohol Drinking; Allergens; Automobile Driving; Coal Mining; Environmental Exposure; Humans; Magnetic Resonance Imaging; Mental Health; Motor Activity; Occupational Injuries; Sensory Thresholds; Signal Transduction; Teaching; Tobacco Smoke Pollution; Tumor Suppressor Protein p53; Vinyl Chloride
PubMed: 24464561
DOI: 10.2478/s13382-013-0168-1 -
Environmental Health Perspectives Oct 1981The National Institute for Occupational Safety and Health (NIOSH) in early 1974 began industrial hygiene studies of vinyl chloride exposed workers. Three VC monomer...
The National Institute for Occupational Safety and Health (NIOSH) in early 1974 began industrial hygiene studies of vinyl chloride exposed workers. Three VC monomer plants, three VC polymerization plants, and seven PVC fabrication plants were surveyed. V polymerization plant workers and workers in one job category in VC monomer plants were exposed to average levels above 1 ppm. The highest average exposure was 22 ppm. NIOSH health hazard evaluation studies since these initial surveys have primarily shown nondetectable levels of vinyl chloride. A NIOSH control technology study in 1977 showed that exposure levels in VC polymerization plants had been drastically reduced but exposure levels above 1 ppm were still found in several cases.
Topics: Air Pollutants; Air Pollutants, Occupational; Chemical Industry; Environmental Exposure; Humans; Polyvinyl Chloride; Polyvinyls; Vinyl Chloride; Vinyl Compounds
PubMed: 7333231
DOI: 10.1289/ehp.8141129 -
British Journal of Industrial Medicine Nov 1985The Association of Plastic Manufacturers in Europe maintains a register of all cases of angiosarcoma of the liver (ASL) resulting from exposure to vinyl chloride monomer...
The Association of Plastic Manufacturers in Europe maintains a register of all cases of angiosarcoma of the liver (ASL) resulting from exposure to vinyl chloride monomer (VCM). This register has recorded all known VCM related cases of the disease worldwide that have been histologically confirmed. Although likely to be incomplete, it is the most comprehensive tabulation of such cases available and, by the end of 1984, 118 men had been registered. The information from analysis of the cases currently on the register is used to make an approximate projection of the number of cases to be expected in the future. The conclusion from this projection is that the industry is reaching the halfway stage in the appearance of VCM related ASL.
Topics: Adult; Aged; Europe; Hemangiosarcoma; Humans; Liver Neoplasms; Male; Middle Aged; Occupational Diseases; Plastics; Registries; South America; Vinyl Chloride; Vinyl Compounds
PubMed: 4063218
DOI: 10.1136/oem.42.11.750 -
Environmental Health Perspectives Feb 1997One of the challenges in environmental health is to attribute a certain health effect to a specific environmental exposure and to establish a cause-effect relationship.... (Review)
Review
One of the challenges in environmental health is to attribute a certain health effect to a specific environmental exposure and to establish a cause-effect relationship. Molecular epidemiology offers a new approach to addressing these challenges. Mutations in the tumor suppressor gene p53 can shed light on past environmental exposure, and carcinogenic agents and doses can be distinguished on the basis of mutational spectra and frequency. Mutations in p53 have successfully been used to establish links between dietary aflatoxin exposure and liver cancer, exposure to ultraviolet light and skin cancer, smoking and cancers of the lung and bladder, and vinyl chloride exposure and liver cancer. In lung cancer, carcinogens from tobacco smoke have been shown to form adducts with DNA. The location of these adducts correlates with those positions in the p53 gene that are mutated in lung cancer, confirming a direct etiologic link between exposure and disease. Recent investigations have also explored the use of p53 as a susceptibility marker for cancer. Furthermore, studies in genetic toxicology have taken advantage of animals transgenic for p53 to screen for carcinogens in vivo. In this review, we summarize recent developments in p53 biomarker research and illustrate applications to environmental health.
Topics: Aflatoxin B1; Environmental Exposure; Environmental Health; Environmental Monitoring; Genes, p53; Genetic Markers; Humans; Molecular Epidemiology; Mutation; Neoplasms; Polymorphism, Genetic; Smoking; Ultraviolet Rays; Vinyl Chloride
PubMed: 9114284
DOI: 10.1289/ehp.97105s1155 -
Polymers Jan 2023Poly(vinyl chloride), PVC, has many attractive properties, including low cost of manufacture, resistance to acid and alkali corrosion, and ease of molding. However, PVC...
Poly(vinyl chloride), PVC, has many attractive properties, including low cost of manufacture, resistance to acid and alkali corrosion, and ease of molding. However, PVC suffers from aging in harsh conditions, leading to the shortening of its useful life. Stability to irradiation, for example, can be improved through the incorporation of additives to PVC. The design, synthesis, and application of new stabilizers continue to attract attention. The current work investigates the effect of three tin-cephalexin complexes on the stability of PVC on irradiation with ultraviolet (UV) light (λ = 313 nm) at 25 °C for a long duration. The PVC was blended with tin-cephalexin complexes at low concentrations (0.5% by weight), and thin films (around 40 µm) were made from the mixed materials. Various methods, including weight loss, infrared spectroscopy, and surface inspection of irradiated films were used to investigate the role played by these additives in the inhibition of PVC photodecomposition. The results confirmed that the additives led to a significant reduction in the rate of photodecomposition of the PVC blends. Tin-cephalexin complexes can absorb harmful radiation, deactivate hydrogen chloride, and scavenge high-energy species such as peroxides, therefore acting as stabilizers for PVC.
PubMed: 36771851
DOI: 10.3390/polym15030550 -
British Journal of Industrial Medicine Feb 1985
Topics: Humans; Neoplasms; Occupational Diseases; Vinyl Chloride; Vinyl Compounds
PubMed: 3970874
DOI: 10.1136/oem.42.2.73 -
Polymers Mar 2019Lanthanum sulfadiazine (LaSD) was synthesized from sulfadiazine and lanthanum nitrate using water as solvent under alkaline conditions, and was used as a novel rare...
Development and Investigation of Lanthanum Sulfadiazine with Calcium Stearate and Epoxidised Soyabean Oil as Complex Thermal Stabilizers for Stabilizing Poly(vinyl chloride).
Lanthanum sulfadiazine (LaSD) was synthesized from sulfadiazine and lanthanum nitrate using water as solvent under alkaline conditions, and was used as a novel rare earth thermal stabilizer to stabilize poly(vinyl chloride) (PVC). The structure of LaSD was characterized by elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR) and thermo- gravimetric analysis (TGA). The influence of lanthanum sulfadiazine with calcium stearate (CaSt₂) and epoxidized soybean oil (ESBO) on stabilizing PVC was studied by using the Congo red test, oven discoloration test, UV-vis spectroscopy and thermal decomposition kinetics. The results showed that the addition of LaSD as a thermal stabilizer can significantly improve the initial whiteness and long-term stability of PVC. In addition, the synergies between LaSD, ESBO, and CaSt₂ can provide outstanding improvement in the long-term thermal stability of PVC. When the ratio of LaSD/ESBO/CaSt₂ is 1.8/0.6/0.6, its thermal stability time is 2193 s which is the best state for stabilizing PVC. Furthermore, comparing the reaction energy (E) and the variations in the conjugate double bond concentration in PVC samples, the order of thermal stability of PVC was PVC/LaSD/ESBO/CaSt₂ > PVC/LaSD/ESBO > PVC/LaSD. The thermal stability mechanism of LaSD on PVC was studied by the AgCl precipitation method and FTIR spectrum. The results showed that the action of LaSD on PVC was achieved through replacing unstable chlorine atoms and absorbing hydrogen chloride.
PubMed: 30960515
DOI: 10.3390/polym11030531 -
The Yale Journal of Biology and Medicine 1978The liver's role in vinyl chloride toxicity and carcinogenicity is providing a better understanding of the chemical carcinogenesis mechanism. A variety of both malignant...
The liver's role in vinyl chloride toxicity and carcinogenicity is providing a better understanding of the chemical carcinogenesis mechanism. A variety of both malignant and benign hepatic tumors has been demonstrated with prolonged exposure to vinyl chloride. The multi-system involvment of this carcinogen and toxin has provided a model for the study of chemical carcinogenesis common to both man and animal. Clinical studies have shown the usefulness of biochemical, radioisotopic, and radiological studies in the detection of toxic and carcinogenic lesions. Animal studies have demonstrated the biochemical metabolism by the liver of vinyl chloride-produced intermediates which are mutagenic in bacterial systems and may be the ultimate carcinogens. Hepatic subcellular enzyme studies prove preliminary evidence of cellular adaptation and increased detoxification. Disruption of this oxidization and detoxification balance may be the key to the malignant transformation of cells. A working hypothesis is presented which may explain the metabolism of vinyl chloride into mutagenic intermediates by the liver cell and the development of malignant transformation by extra hepatic sinusoidal lining cells, lung cells, and brain tissue.
Topics: Animals; Carcinogens, Environmental; Collagen; Cricetinae; Hemangiosarcoma; Humans; Inactivation, Metabolic; Liver; Liver Neoplasms; Mice; Models, Biological; Rats; Vinyl Chloride; Vinyl Compounds
PubMed: 566989
DOI: No ID Found