Burning Polyvinyl Chloride Research Articles

Quantitative structure–property relationships on direct photolysis of PCDD/Fs on surfaces of fly ash

Fly ash samples containing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were generated by combustion of polyvinyl chloride, wood, high-density polyethylene and styrene. By partial least-squares (PLS) regression, quantitative structure–property relationship (QSPR) models were developed for photolysis half-lives (t 1/2) of PCDD/Fs adsorbed on fly ash surfaces and irradiated by UV-B of simulated sunlight. Quantum chemical descriptors computed by PM3 hamiltonian were used as predictor variables. The cross validated value for the optimal QSPR model was 0.678, indicating robustness and good predictive abilities of the model. The QSPR results showed that the stability of the PCDD/F molecules increased with the increase of chlorine atoms in the parent molecules. Increasing the energy of the highest occupied molecular orbital (E HOMO), the energy of the lowest unoccupied molecular orbital (E LUMO), E LUMO+E HOMO and E LUMO-E HOMO values of the PCDD/Fs led to decrease of log t 1/2 values. Increasing the most negative atomic charge on the oxygen atom of PCDD/Fs led to elevated log t 1/2 values. The log t 1/2 values of PCDD/Fs increased with the decrease of the largest negative atomic charge on a carbon atom.

Emission Characteristics of PCDD/Fs, PCBs, Chlorobenzenes, Chlorophenols, and PAHs from Polyvinylchloride Combustion at Various Temperatures

The effect of temperature on polyvinylchloride (PVC) combustion using a downstream tubular furnace was investigated for the formation of polycylcic aromatic hydrocarbons (PAHs) and chlorinated compounds. As the temperature increased, higher levels of PAHs were generated. Chlorinated compounds reached a peak at 600°C, with low emissions recorded at 300 and 900°C. There was a close correlation (R2 = 0.97) among polychlorinated bi-phenyls (PCBs), hexachlorobenzene, pentachloroben-zene, and polychlorinated dibenzo-p-dioxins and poly-chlorinated dibenzofurans (PCDD/Fs). PAHs at all temperatures were analyzed in the gas phase. PCDD/Fs and PCBs were emitted as a solid phase at 300 and 600°C and as a gas phase at 900°C. For some PAHs, chloroben-zenes, and PCDD/Fs, a mathematical equation between the gas and solid phase and the reciprocal temperature in semilog proportion was derived. The proposed equation, which is log (amount in gas phase/amount in solid phase) = −A/T + B, where T is the temperature of the furnace and A and B are constants, for these species relating their gas/solid distributions showed a good relationship.

Analysis and structure prediction of chlorinated polycyclic aromatic hydrocarbons released from combustion of polyvinylchloride

Chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) released from combustion of polyvinylchloride (PVC) at different furnace temperatures were investigated. A laboratory-scale tube-type furnace with electric heating was utilized to control combustion conditions. Glass fabric filters and adsorbents were used to collect the combustion emissions. Following Soxhlet extraction, concentration and column chromatography purification, isomers separation, selective detection and identification of Cl-PAHs were performed on GC/MS system on the basis of retention data and mass spectra. Their quantification was accomplished by using external standard calibration technique. About 18 Cl-PAHs were determined, most of which were monochlorinated derivatives of naphthalene, biphenyl, fluorene, phenanthrene, anthracene, fluoranthene and pyrene. Only two dichlorophenanthrenes or anthracenes were identified. The possible positions of chlorine atoms attached to the aromatic rings are predicted by quantitative structure–property relationship. The levels of these compounds were in the range of 0.30–29.08 μg/g PVC. The relationship between the formation of Cl-PAHs and PAHs was discussed.

Photolysis of polycyclic aromatic hydrocarbons adsorbed on spruce [Picea abies (L.) Karst.] needles under sunlight irradiation

Photolysis of polycyclic aromatic hydrocarbons (PAHs) sorbed on surfaces of spruce [Picea abies (L.) Karst.] needles under sunlight irradiation was investigated. PAHs were produced by combustion of polyvinyl chloride (PVC), wood, high-density polyethylene (HDPE), and styrene in a stove. The factors of sunlight irradiation on the surfaces of spruce needles were taken into consideration when investigating the kinetic parameters. The photolysis of the 18 PAHs under study follows first-order kinetics. The photolysis half-lives range from 15 h for dibenzo(a,h)anthracene to 75 h for phenanthrene. Photolysis of some PAHs on surfaces of spruce needles may play an important role on the fate of PAHs in the environment.

Photodegradation of PCDD/Fs adsorbed on spruce ( Picea abies (L.) Karst.) needles under sunlight irradiation

Spruce ( Picea abies (L.) Karst.) needles were exposed to exhaust gas containing polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/Fs) generated by combustion of polyvinyl chloride, wood, high-density polyethylene, and styrene. Photodegradation of PCDD/Fs adsorbed on spruce needles under sunlight irradiation was studied. The photodegradation of PCDD/Fs follows pseudo-first-order reaction kinetics, with photolysis half-lives ranging between 40 and 100 h. The photolysis rates of PCDF congeners are higher than PCDD congeners with the same chlorinated substitutions. Higher chlorinated PCDD/Fs tend to photolyze slowly. The wax components in spruce needles may act as proton donors and accelerate the photolysis rate. C–Cl cleavage through the addition of protons to PCDD/F molecules may be an important route for PCDD/Fs photodegradation.

Effect of copper chloride on the emissions of PCDD/Fs and PAHs from PVC combustion.

The influences of temperature, air flow and the amount of copper chloride upon the types and amount of the toxic emissions such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs) during combustion of polyvinyl chloride (PVC) were investigated. The mechanism concerning the effect of temperature and copper chloride on the PCDD/Fs and PAHs formation was discussed. The results shown that without copper chloride, trace amounts of PCDD/Fs and large amounts of PAHs were found in the emissions from the pure PVC combustion under various combustion conditions. The addition of copper chloride enhanced PCDD/Fs formation, but it seems that the formation of PAHs decreased with increasing amount of copper chloride, and greater total amount of PAHs were produced at the higher temperature under our experimental conditions.

Particulates Generated from Combustion of Polymers (Plastics)

ABSTRACT Yiannis A. Levendis is a professor in the Department of Mechanical, Industrial, and Manufacturing Engineering at Northeastern University. He holds a B.S. and an M.S. in mechanical engineering from the University of Michigan and a Ph.D. in environmental engineering from the California Institute of Technology. Brooke Shemwell is a graduate research assistant in the Department of Mechanical, Industrial, and Manufacturing Engineering at Northeastern University. This is an experimental study on the characterization of particulate (soot) emissions from burning polymers. Emissions of polystyrene (PS), polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), and polyvinyl chloride (PVC) plastics were studied. Combustion took place in a laboratory-scale, electrically heated, drop-tube furnace at temperatures of 1300 and 1500 K, in air. The nominal bulk (global) equivalence ratio, φ, was varied in the range of 0.5-1.5, and the gas residence time in the nearly isothermal radiation zone of the furnace was ≈ 1 sec. The particulate emissions were size-classified at the exit of the furnace, using a multi-stage inertial particle impactor. Results showed that both the yields and the size distributions of the emitted soot were remarkably different for the five plastics burned. Soot yields increased with an increasing bulk equivalence ratio. Combustion of PS yielded the highest amounts of soot (most highly agglomerated), several times more than the rest of the polymers. More soot was emitted from PS at 1500 than at 1300 K. Substantial amounts of soot agglomerates were larger than 9 μm. At 1500 and 1300 K, 35 and 29% of the soot mass, respectively, was PM2 (2 μm or smaller). Emissions from PE and PP were remarkably similar to each other. These polymers produced very low emissions at f< 0.5, but emissions increased drastically with f, and most of the soot was very fine (70-97% of the mass was PM2, depending on f). Emissions from the combustion of PMMA were comparatively low and were the least influenced by the bulk f, and 79–95% of the emissions were PM2. Combustion of PVC yielded the lowest amounts of soot; moreover, only 13–34% of the mass was PM2. On a comparative basis, at 1500 K, the following ranges of particulate yields were PM2: 19–75 mg/g of PS, 8–36 mg/g of PE, 1.5–47 mg/g of PP, 11–20 mg/g of PMMA, and 2–8 mg/g of PVC, depending on f. These comparative results demonstrate that PS produces the highest amounts of fine particulates, followed by PP, PE, and PMMA, and then PVC. Burning these materials with excess oxygen drastically reduces the par-ticulate emissions of PE and PP, substantially reduces those of PS, and mildly reduces those of PMMA and PVC.

Mutagenic substances in pyrolysate obtained by burning polyvinylchloride-product at 1000°C

In order to detect possible mutagenic substances in pyrolysate obtained by burning polyvinyl chloride product (PVC-P) at approximately 1000°C, mutagenicity of rough extracts obtained by extraction with various solvents for the products was investigated by means of reversion mutation assay using Salmonella typhimurium TA98 and TA100 with or without microsomal metabolic activation (S9 mix). Strong mutagenicity in TA98 without S9 mix was observed in acetone-extract of PVC-P. The extract was fractionated into acidic, neutral and basic by liquid–liquid distribution and the mutagenicity in TA98 without S9 mix was found in the neutral fraction. Identification of mutagenic substances in the neutral fraction from acetone extract, which showed the strongest mutagenicity, was attempted by means of thin layer chromatography and capillary gas chromatography. The results suggest that mutagenic substances from pyrolysate of PVC-P are benzanthrone and an isomer of benzo( c)cinnoline. The results also suggest that burning wastes containing plastic products is not always safe even if at 1000°C and further research on the problem is necessary.

Fire Detection Using Quartz Crystal Microbalance Chemical Sensors

The new application of piezoelectric quartz-crystal microbalance (QCM) sensors to fire detection is described. The QCM sensors are coated with plasma organic films which are sensitive to vapors emitted from burning polyvinyl chloride (PVC) cables and epoxy resin circuit boards. These vapors must be distinguished because these sensors also respond to humidity. Principal component analysis reveals that this system can discriminate between vapors emitted from burning materials and humidity. Vapor discrimination is also described using the Kohonen's Learning Vector Quantization (LVQ).

Application of plasma-polymer-film-coated sensors to gas identification using linear filters

A chemical sensing system that uses a new type of sensor film and digital signal processing of sensor dynamic responses is described. It consists of quartz-crystal microbalances coated with plasma-polymer films. The sensor dynamic responses include information about the target gases, and are described by linear filters the coefficients of which reflect the sensor's dynamics and which can extract the dynamic parameters, even when the gas concentrations change, using multiple sensors with different dynamic characteristics. This method is applicable to various uses under practical conditions. The application of the proposed method to a fire-alarm system is described. This system can discriminate between the gases from burning polyvinyl chloride (PVC) cables and circuit boards, Finally, some simulation results indicate that it is significant for these sensors to have different dynamic properties when the sensors' outputs are greatly disturbed by noise.

Acute and Long-Term Effects of Polyvinylchloride (PVC) Smoke on the Respiratory System of the Baboon and a Comparison with the Effects of Hydrogen Chloride (HCl

The acute and long-term effects of smoke produced by flaming and nonflaming combustion of PVC were investigated in the baboon and com pared with those produced by HCl. Four groups of three anesthetized adult male baboons ( Papio cynocephalus) were exposed for 15 minutes to air (con trols), flaming or nonflaming PVC smoke containing a targeted 5000 ppm con centration of HCl, or to HCl at a targeted concentration of 5000 ppm. The ani mals responded to flaming or nonflaming PVC smoke with an increase in frequency and minute volume, accompanied by decreased arterial pH and PaO2 and increased PaCO2 values. Although pulmonary function tests, CO2 chal lenge tests, or arterial blood gas measurements in PVC smoke-exposed animals showed sporadic differences from controls at 90, 180, or 360 days postexposure, the results did not indicate the development of impaired pulmonary function. These results were consistent with the absence of exposure-related respiratory tract pathology, although an inflammatory cell response was noted in the minor airways of one animal exposed to flaming PVC smoke. The effects of flam ing or nonflaming PVC smoke were generally similar to those of HCl, in dicating that HCl is retained in the upper respiratory tract, even in the pres ence of particulates in smoke.

Combined wet oxidation and alkaline hydrolysis of polyvinylchloride

In view of the widespread aversion to burning polyvinylchloride (PVC) together with municipal waste, we have attempted an alternative approach to its decomposition. This paper describes a combined wet oxidation/alkaline hydrolysis yielding water soluble, biodegradable products. Experiments were carried out at temperatures from 180–260°C and reaction times of 8–24 min. The chloride liberated provides information on the rate constants. Considering the measured Cl − and Chemical Oxygen Demand (COD) values, we find hydrolysis and oxidation processes to be interdependent. The main products are Cl − and CO 2, the rest comprising a range of water-soluble compounds, a small, Cl-free residue, and a recognizable amount of H 2.

Acute health effects among firefighters exposed to a polyvinyl chloride (PVC) fire.

Firefighters are frequently being called on to fight fires that are chemical in nature. In the aftermath of a chemical fire in Plainfield, New Jersey on March 20-21, 1985, the authors conducted a retrospective cohort study which surveyed 80 firefighters exposed to burning polyvinyl chloride (PVC) as well as 15 nonexposed firefighter subjects. By means of an 81-item symptom checklist, exposed firefighters reported more frequent and severe symptoms at 5-6 weeks post incident. This was true for a total symptomatology score as well as 19 individual items. Some of the items with an elevated risk were consistent with exposure to hydrogen chloride, the main pyrolysis product of polyvinyl chloride. Other items with an elevated risk appeared to be related to smoke inhalation while others seemed psychosocial in nature. Analyses conducted within the exposed firefighter group showed that fighting the fire the first day, being a truckman, and residence within 1 mile (1.6 km) of the firehouse were significant risk factors for high total symptom scores. These risk factors may have been associated with level or duration of exposure to the toxic substances produced during the fire.

Self-reported short- and long-term respiratory effects among PVC-exposed firefighters.

Firefighters exposed to burning polyvinyl chloride (PVC) were studied to assess respiratory effects at 5-6 wk post-incident and again 22 mo following the fire. Exposed subjects reported significantly more frequent and severe respiratory symptoms at both time points than did firefighter controls. In longitudinal analyses, a number of symptoms persisted over time, and acute symptom scores were significantly correlated with chronic scores. At Time 2, approximately 18% of exposed firefighters, compared with none of the controls, reported that since the time of the PVC exposure, a physician had told them that they had either asthma and/or bronchitis.

Combustion of polyvinylchloride - an important source for the formation of PCDD/PCDF

Report is given on the combustion and pyrolysis conditions. The analytical procedure is described. During combustion and pyrolysis of pure polyvinylchloride (PVC) and PVC-cable sheathings in an air atmosphere, PCDD/PCDF are formed in significant amounts up to the ppm range. In general furans were formed predominantly. Especially higher levels of octa- and heptachlorinated furans were generated in the pyrolysis experiments, whereas lower chlorinated furans were produced predominantly by combustion.

The Combustion Toxicology of Polyvinylchloride Revisited

The combustion toxicology of polyvinylchloride (PVC) has been studied exten sively against a background of increasing understanding of the relevance of the toxicity of combustion products in fires. Most materials have a similar toxic potency and demonstrate asphyxia and irritancy when thermally decomposed. Hydrogen chloride is a major toxicant produced by PVC, which accounts for the irritancy shown by PVC combustion products. Carbon monoxide is also pro duced which becomes the most significant toxicant if the hydrogen chloride levels are reduced, which can occur rapidly in fires. The toxic potency lies within the range of 300-3000 mg/l. mins, which is similar to the majority of polymeric materials whether natural or synthetic.

The role of molybdenum in flame retardancy and smoke retardation

Molybdenum compounds have been known for a long time to act as flame retardants in cellulosics. More recent interest in various materials, especially plastics, that would require reduction in both flammability and smoke has increased the potential for molybdenum compounds in such applications. This paper gives details of work carried out at Climax Molybdenum Company to develop effective formulations for reduced flammability and smoke formation in various plastic systems employing molybdenum compounds such as MoO 3, (NH 4) 4Mo 8O 26, Moly FR-21 etc. In some typical plasticised polyvinyl chloride formulations these compounds were shown to be effective both as flame retardants and as smoke suppressants. Similar results were obtained with some reinforced halogenated polyesters. These polyesters are known to produce large amounts of smoke; considerable reductions were realised by the addition of molybdenumcontaining materials. The use of molybdenum compounds in similar applications in other plastic systems is discussed. Studies of burning polyvinyl chloride samples treated with molybdenum or antimony have shown that all the molybdenum remains in the char, whereas over 90% of the antimony has volatilised; this indicates that these two materials have different mechanisms of flame retardancy.

Polyvinyl Chloride in Fires

<h3>To the Editor.—</h3> The article "Polyvinyl Chloride Toxicity in Fires" by Dyer and Esch (235:393-397, 1976) contains a number of factual errors and certain misleading inferences. In three places, the combustion of polyvinyl chloride (PVC) is said to produce chlorine and phosgene. In fact, these two materials have never been demonstrated to occur in the pyrolysis or combustion of PVC (<i>Journal of Polymer Science</i>8:1887-1890, 1970;<i>Journal of Applied Polymer Science</i>13:377-391,1969;<i>British Polymer Journal</i>3:186-193, 1971;<i>Journal of Applied Chemistry</i>17:366, 1967). The authors point out, correctly, that hydrochloric acid and carbon monoxide are the main toxic combustion products of PVC but tie these to possible toxic synergy with chlorine or phosgene. It is wrong to raise the specter of toxicants which are not really there. In another instance, vinyl chloride is said to be produced. In work by Boettner et al (<i>Journal of Applied Polymer Science</i>13:377-391, 1969),

Acute inhalation-intoxication by combustion of polyvinylchloride.

The pulmonary effects of an acute intoxication by inhalation of gases produced by combustion of polyvinylchloride are studied in 20 persons.

Polymer pyrolysis: hydrogen cyanide from the open burning of orlon.

Abstract While designing a freshman chemistry laboratory experiment to demonstrate the production of hydrogen chloride by burning polyvinyl chloride, we happened to recall the analogy between inorganic cyanide and halide. Orlon (“polyvinyl cyanide”) might, when burned, produce hydrogen cyanide. Subsequent experimentation confirmed the production of this highly toxic gas during the combustion of Orlon.