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Synthesis of a Solid Superacid and Its Application in Flame-Retardant Poly(vinyl chloride) Material.ACS Omega Apr 2019TiO/PO solid superacid was synthesized by using the precipitation immersion method and characterized by means of X-ray diffraction (XRD) and an energy-dispersive...
TiO/PO solid superacid was synthesized by using the precipitation immersion method and characterized by means of X-ray diffraction (XRD) and an energy-dispersive spectrometer; it was added into flexible poly(vinyl chloride) (PVC) composites as a flame retardant. The smoke suppression and flame retardance of TiO/PO accompanied by SbO were investigated through the limiting oxygen index (LOI), cone calorimetry test, and thermogravimetry analysis (TGA). The results indicated that the LOI value of PVC/SbO/(TiO/PO ) reached to 32.3%, which is higher by 6% than that of neat PVC (26.3%). In addition, SbO/(TiO/PO ) greatly reduced the peak heat release rate and total heat release simultaneously in comparison to using SbO separately, suggesting a significant synergistic effect between TiO/PO and SbO on improving the flame retardancy of the PVC. Further, results of TGA and differential thermal analysis showed that the thermal stability of the composites was greatly improved. For the Fourier transform infrared analysis, SbO/(TiO/PO ) leads to a large amount of functional group surplus, which specifically indicates that its carbon residue increases. The surface of the char formed after combusting of the PVC compounds was observed through scanning electron microscopy. It is found that the solid superacid can promote decomposition, pyrolysis, and cross-linking of PVC into the compact and continuous char layer on the surface of the material, which improved the flame retardancy and smoke suppression of PVC.
PubMed: 31459848
DOI: 10.1021/acsomega.9b00368 -
Cardanol Groups Grafted on Poly(vinyl chloride)-Synthesis, Performance and Plasticization Mechanism.Polymers Nov 2017Internally plasticized poly(vinyl chloride) (PVC) materials are investigated via grafting of propargyl ether cardanol (PEC). The chemical structure of the materials was...
Internally plasticized poly(vinyl chloride) (PVC) materials are investigated via grafting of propargyl ether cardanol (PEC). The chemical structure of the materials was studied by FT-IR and ¹H NMR. The performace of the obtained internally plasticized PVC materials was also investigated with TGA, DSC and leaching tests. The results showed that grafting of propargyl ether cardanol (PEC) on PVC increased the free volume and distance of PVC chains, which efficiently decreased the glass transition temperature (). No migration was found in the leaching tests for internally plasticized PVC films compared with plasticized PVC materials with commercial plasticizer dioctyl phthalate (DOP). The internal plasticization mechanism was also disscussed according to lubrication theory and free volume theory. This work provides a meaningful strategy for designing no-migration PVC materials by introducing cardanol groups as branched chains.
PubMed: 30965920
DOI: 10.3390/polym9110621 -
British Journal of Industrial Medicine Feb 1984The results of a follow up study of the incidence of cancer and the mortality in a cohort of 454 male workers producing vinyl chloride and polyvinyl chloride are...
The results of a follow up study of the incidence of cancer and the mortality in a cohort of 454 male workers producing vinyl chloride and polyvinyl chloride are presented. The study population was restricted to employees with more than one year's work experience in the study plant between 1950 and 1969 and the cohort was followed up from 1953 to the end of 1979. Twenty three new cases of cancer were observed compared with 20.2 expected; one case of liver angiosarcoma was found. Five cases of lung cancer were found (2.8 expected) and four cases of malignant melanoma of the skin were observed (0.8 expected). The possibility of a causal relationship between exposure to vinyl chloride and the development of malignant melanomas is discussed.
Topics: Adult; Aged; Chemical Industry; Follow-Up Studies; Humans; Male; Middle Aged; Neoplasms; Norway; Occupational Diseases; Occupations; Polyvinyl Chloride; Polyvinyls; Time Factors; Vinyl Chloride; Vinyl Compounds
PubMed: 6691932
DOI: 10.1136/oem.41.1.25 -
Polymers Jan 2023Primer is widely used to prepare bonding of chlorinated poly(vinyl chloride) (CPVC) pipe. The study examined the influences of primer and its major component, acetone,...
Primer is widely used to prepare bonding of chlorinated poly(vinyl chloride) (CPVC) pipe. The study examined the influences of primer and its major component, acetone, on CPVC's mechanical properties. Two types of CPVC product, sheet and pipe, were used in the mechanical testing. Sheet specimens were immersed in acetone or primer for 40 and 10 min, respectively, i.e., the maximum allowable time without mass loss, and then dried in air before the mechanical testing. Pipe (ring) specimens were treated either through immersion in acetone or primer for 30 min or in contact with these solvents locally on the inner surface for 2.5 h, and then air dried for 10.5 days before the mechanical testing. Results showed that CPVC's strength decreased after the absorption of these solvents, and air dry could remove acetone but not completely primer. The study also showed that pipe specimens by local contact with primer could generate brittle fracture. In view that sheet specimens always fractured in a ductile manner, brittle fracture of the pipe specimens could not be caused by CPVC degradation. Rather, strength decrease in the local region could provide a plausible explanation for the brittle fracture behavior, though further investigation is needed.
PubMed: 36771790
DOI: 10.3390/polym15030489 -
ACS Omega Sep 2021As a filler to be inserted into poly(vinyl chloride) (PVC), low-cost olive pits flour (OPF) and precipitated bio-calcium carbonate (PBCC)-produced PVC/OPF/PBCC...
As a filler to be inserted into poly(vinyl chloride) (PVC), low-cost olive pits flour (OPF) and precipitated bio-calcium carbonate (PBCC)-produced PVC/OPF/PBCC composites have been used with high stability and rigidity compared to PVC. Hydrogen bonding is generated between OH cellulose in OPF and H in PVC. Composite tensile modulus increased in PVC grid in the presence of PBCC and OPF, possibly because of a filler restriction effect on the polymer chains. The hardness also increased as both OPF and PBCC increased. The mechanical tendency of the PVC/OPF composite was improved by adding a low content of PBCC particles with the PVC network, resulting in a smart distribution in the range of 10% by weight, and it was reduced by adding more than that percentage. The successful distribution of PBCC in PVC/OPF composite strengthened the mechanical path. The morphology and possible interface adhesion of components in the composite were demonstrated by scanning electron microscopy (SEM). The PVC SEM images showed a homogeneous, smart, and consistent surface, while the PVC/60 wt % OPF SEM images showed a large number of voids that suggested weak PVC/OPF interactions. The SEM images showed outstanding PBCC distribution in the PVC/OPF matrix for the PVC/50 wt % OPF/10 wt % PBCC composite. Due to the accumulation of PBCC particles producing cavities, the distribution of particles became nonhomogeneous at percentages above 10 wt %. At a low filler material, better spread of PBCC particles in the PVC grid was achieved. Owing to the polarity of OPF, the HO absorption and thickness swelling of PVC/OPF/PBCC composites showed higher amounts than PVC. PBCC improved the thermal stabilization and the neutralization of Cl negative ions as an acid acceptor of secondary PVC stabilization.
PubMed: 34568671
DOI: 10.1021/acsomega.1c02932 -
Environmental Health Perspectives Jul 2000Vinyl chloride (VC) is both a known carcinogen and a regulated chemical, and its production capacity has almost doubled over the last 20 years, currently 27 million... (Review)
Review
Vinyl chloride (VC) is both a known carcinogen and a regulated chemical, and its production capacity has almost doubled over the last 20 years, currently 27 million tons/year worldwide. According to recent reports it is still a cause for concern. VC has been found as a degradation product of chloroethylene solvents (perchloroethylene and trichloroethylene) and in landfill gas and groundwater at concentrations up to 200 mg/m(3) and 10 mg/L, respectively. Worldwide occupational exposure to VC still seems to be high in some countries (e.g., averages of approximately 1,300 mg/m(3) until 1987 in one factory), and exposure may also be high in others where VC is not regulated. By combining the most relevant epidemiologic studies from several countries, we observed a 5-fold excess of liver cancer, primarily because of a 45-fold excess risk from angiosarcoma of the liver (ASL). The number of ASL cases reported up to the end of 1998 was 197 worldwide. The average latency for ASL is 22 years. Some studies show a small excess risk for hepatocellular carcinoma, and others suggest a possible risk of brain tumors among highly exposed workers. Lung cancer, lymphomas, or leukemia do not seem to be related to VC exposure according to recent results. The mutation spectra observed in rat and human liver tumors (ASL and/or hepatocellular carcinoma) that are associated with exposure to VC are clearly distinct from those observed in sporadic liver tumors or hepatic tumors that are associated with other exposures. In rats, the substitution mutations found at A:T base pairs in the ras and p53 genes are consistent with the promutagenic properties of the DNA adduct 1,N(6)-ethenoadenine formed from VC metabolites. Risk assessments derived from animal studies seem to overestimate the actual risk of cancer when comparing estimated and reported cases of ASL.
Topics: Animals; Carcinogens; Carcinoma, Hepatocellular; Environmental Exposure; Epidemiologic Studies; Hemangiosarcoma; Humans; Liver Neoplasms; Occupational Exposure; Rats; Risk Assessment; Vinyl Chloride
PubMed: 10905993
DOI: 10.1289/ehp.00108579 -
Occupational and Environmental Medicine Oct 2017To evaluate mortality risks of angiosarcoma of the liver (ASL), primary hepatocellular carcinoma (HCC) and other cancers among 9951 men employed between 1942 and 1972 at...
Quantitative estimated exposure to vinyl chloride and risk of angiosarcoma of the liver and hepatocellular cancer in the US industry-wide vinyl chloride cohort: mortality update through 2013.
OBJECTIVE
To evaluate mortality risks of angiosarcoma of the liver (ASL), primary hepatocellular carcinoma (HCC) and other cancers among 9951 men employed between 1942 and 1972 at 35 US vinyl chloride (VC) or polyvinyl chloride plants followed for mortality through 31 December 2013.
METHODS
SMR and time-dependent Cox proportional hazards analyses were used to evaluate mortality risks by cumulative VC exposure.
RESULTS
Liver cancer mortality was elevated (SMR=2.87, 95% CI 2.40 to 3.40), and ASL and HCC were strongly associated with cumulative VC exposure ≥865 parts per million-years (ppm-years) (ASL: HR=36.3, 95% CI 13.1 to 100.5; and HCC: HR=5.3, 95% CI 1.6 to 17.7 for ≥2271 ppm-years). Excess deaths due to connective and soft tissue cancers (SMR=2.43, 95% CI 1.48 to 3.75), mesothelioma (SMR=2.29, 95% CI 1.18 to 4.00) and explosions (SMR=3.43, 95% CI 1.25 to 7.47) were seen. Mortalities due to melanoma, brain cancer, lung cancer and non-Hodgkin's lymphoma were not increased or associated with VC exposure.
CONCLUSION
The association between VC and ASL first reported in this cohort 44 years ago persisted and was strongest among workers most highly exposed. VC exposure also was associated with HCC mortality, although it remains possible that misdiagnosis of early ASLs influenced findings.
Topics: Adult; Aged; Aged, 80 and over; Cause of Death; Hemangiosarcoma; Humans; Liver; Liver Neoplasms; Male; Manufacturing Industry; Middle Aged; Occupational Diseases; Occupational Exposure; Polyvinyl Chloride; Proportional Hazards Models; Risk; United States; Vinyl Chloride
PubMed: 28490663
DOI: 10.1136/oemed-2016-104051 -
Polymers Jun 2021The thermal stability of PVC with 1 wt % of spherical porous nanosilica, prepared by roll milling at processing time varied from 1 to 20 min, was investigated by means...
The thermal stability of PVC with 1 wt % of spherical porous nanosilica, prepared by roll milling at processing time varied from 1 to 20 min, was investigated by means of visual color changes, Congo red, and thermogravimetric tests (TGA and DTG), as a function of rolling time and composition of PVC matrix. The melt flow rate (MFR) measurements were realized to identify the degradation-induced changes of processing properties. A high level of gelation of the PVC matrix for all samples was verified by DSC (differential scanning calorimetry). It was found that the addition of porous nanosilica to absorb a certain volume of HCl, produced by dehydrochlorination reaction, leads to an improvement of thermal stability, an effect observed in a form of minor color changes of the samples, lower evolution of gas hydrogen chloride, and slight changes of the MFR value. It was demonstrated that the TGA measurements are not sufficiently sensible to detect the degradation of PVC at the processing conditions, i.e., at the temperature equal to 220 °C and below this temperature.
PubMed: 34201721
DOI: 10.3390/polym13132057 -
Molecules (Basel, Switzerland) Feb 2019Five Schiff bases derived from melamine have been used as efficient additives to reduce the process of photodegradation of poly(vinyl chloride) films. The performance of...
Five Schiff bases derived from melamine have been used as efficient additives to reduce the process of photodegradation of poly(vinyl chloride) films. The performance of Schiff bases has been investigated using various techniques. Poly(vinyl chloride) films containing Schiff bases were irradiated with ultraviolet light and any changes in their infrared spectra, weight, and the viscosity of their average molecular weight were investigated. In addition, the surface morphology of the films was inspected using a light microscope, atomic force microscopy, and a scanning electron micrograph. The additives enhanced the films resistance against irradiation and the polymeric surface was much smoother in the presence of the Schiff bases compared with the blank film. Schiff bases containing an ortho-hydroxyl group on the aryl rings showed the greatest photostabilization effect, which may possibly have been due to the direct absorption of ultraviolet light. This phenomenon seems to involve the transfer of a proton as well as several intersystem crossing processes.
Topics: Microscopy, Atomic Force; Microscopy, Electron, Scanning; Molecular Structure; Photolysis; Polyvinyl Chloride; Schiff Bases; Triazines; Ultraviolet Rays
PubMed: 30813367
DOI: 10.3390/molecules24040803 -
Molecules (Basel, Switzerland) Jun 2021Poly(vinyl chloride) degrades when exposed to ultraviolet light for long durations; therefore, the photostability of polymeric materials should be enhanced through the...
Poly(vinyl chloride) degrades when exposed to ultraviolet light for long durations; therefore, the photostability of polymeric materials should be enhanced through the application of additives. New organotin complexes containing 4-aminonaphthalene-1-sulfonic acid were synthesized and their role as poly(vinyl chloride) photostabilizers were evaluated. The reaction of 4-amino-3-hydroxynaphthalene-1-sulfonic acid and appropriate di- or trisubstituted tin chloride (triphenyltin chloride, tributyltin chloride, dibutyltin dichloride, and dimethyltin dichloride) in methanol under reflux gave the corresponding tin-naphthalene complexes with yields of 75%-95%. Elemental analyses and spectroscopic techniques including infrared and nuclear magnetic resonance (proton and tin) were used to confirm their structures. The tin complexes were added to poly(vinyl chloride) to produce thin films that irradiated with ultraviolet light. Various parameters were assessed, such as the weight loss, formation of specific functional groups, changes in the surface due to photoirradiation, and rate constant of photodegradation, to test the role played by the organotin complexes to reduce photodegradation in polymeric films. The results proved that organotin complexes acted as photostabilizers in these circumstances. The weight loss, formation of fragments containing specific functional groups, and undesirable changes in the surface of polymeric films were limited in the presence of organotin complexes. Organotin complexes containing three phenyl groups showed the most desirable stabilization effect. These act as efficient primary and secondary photostabilizers, and as decomposers for peroxides. In addition, such an additive inhibits the dehydrochlorination process, which is the main cause of poly(vinyl chloride) photodegradation.
PubMed: 34198519
DOI: 10.3390/molecules26123629