Acrylics: A Literature Review of Thermal Decomposition Products and Toxicity

1988 ◽  
Vol 7 (2) ◽  
pp. 139-200 ◽  
Author(s):  
P.K. Johnston ◽  
E. Doyle ◽  
R.A. Orzel
Keyword(s):  
Thermal Decomposition ◽  
Literature Review ◽  
Combustion Products ◽  
Standard Test ◽  
Test Material ◽  
Decomposition Products ◽  
Time To Death ◽  
Thermal Decomposition Products ◽  
Order Of Magnitude ◽  
Acrylate Polymers

A comprehensive literature review on the thermal decomposition products and combustion toxicity of acrylics is presented. The types of products produced by the thermal decomposition of acrylic polymers vary widely. At lower temperatures, simple methacrylate polymers are degraded almost entirely to monomer, whereas simple acrylate polymers are degraded primarily to chain fragments and the alcohols corresponding to the ester groups. More complex methacrylate and acrylate polymers appear to be degraded primarily to the olefins corresponding to the ester groups. The major products formed through the thermal decomposition of polyacrylonitrile include HCN, NH3, CO, CO2, and various nitrile compounds. The decomposition of acrylonitrile copolymers (e.g., acrylic and modacrylic fibers) can result in the release of additional compounds. In general, modacrylic combustion products appear to be more acutely toxic than those of other acrylic materials tested or wood. Modacrylic produced a shorter time to incapacitation and time to death than poly(methyl methacrylate) in the FAA test, and, in the NBS test, the LC50 was more than fivefold lower than that for polyacrylonitrile. In addition, the LC50 of modacrylic in the University of Pittsburgh test was an order of magnitude lower than that for the standard test material, Douglas fir.

Polypropylene: A Literature Review of the Thermal Decomposition Products and Toxicity

1988 ◽  
Vol 7 (2) ◽  
pp. 221-242 ◽  
Author(s):  
V. Purohit ◽  
R.A. Orzel
Keyword(s):  
Thermal Decomposition ◽  
Literature Review ◽  
Aromatic Hydrocarbons ◽  
Combustion Products ◽  
Aliphatic Hydrocarbons ◽  
Fixed Temperature ◽  
Decomposition Products ◽  
Time To Death ◽  
Thermal Decomposition Products ◽  
The University

This report presents a comprehensive literature review of the thermal decomposition products of polypropylene evolved under pyrolytic and oxidative conditions and the acute toxicity of combustion products of this polymer. Generally, the pyrolysis products of polypropylene (300–700°C) were aliphatic saturated and unsaturated hydrocarbons. The combustion of polypropylene in air (200–600°C) produced oxygenated hydrocarbons, aromatic hydrocarbons, aliphatic hydrocarbons, CO, CO2, and H2O. In general, as combustion temperature and time increased, the proportions of oxygenated and aliphatic hydrocarbons decreased, whereas the proportion of aromatic hydrocarbons increased. Using the University of San Francisco/National Aeronautical and Space Administration (USF/NASA) method under the fixed temperature program, time to death in mice caused by the combustion products of polypropylene decreased as the temperature was increased. Under the rising temperature mode, time to death decreased when polypropylene was combusted under airflow as compared to no airflow conditions. CO levels generated by the combustion of polypropylene were sufficient to produce the lethal effects observed. Using a test method developed at the University of Michigan, the combustion products of polypropylene were found to be 26 times more toxic under dynamic conditions (rising temperature) than under static conditions (fixed temperature).

Flexible Polyurethane Foam: A Literature Review of Thermal Decomposition Products and Toxicity

1989 ◽  
Vol 8 (6) ◽  
pp. 1139-1175 ◽  
Author(s):  
R. A. Orzel ◽  
S. E. Womble ◽  
F. Ahmed ◽  
H. S. Brasted
Keyword(s):  
Thermal Decomposition ◽  
Literature Review ◽  
Polyurethane Foam ◽  
Combustion Products ◽  
Test Methods ◽  
Decomposition Products ◽  
Thermal Decomposition Products ◽  
Flexible Polyurethane Foam ◽  
Flexible Polyurethane ◽  
Combustion Toxicity

This report presents a comprehensive literature review of the toxicity of the combustion products of flexible polyurethane foam and the thermal decomposition products of this polymer. Combustion toxicity results obtained using different test methods but measuring the same toxicologic endpoints were compared. That is, time to incapacitation and time to death using the USF and FAA test methods were compared. Also, LC50 values using the DIN, NBS, and University of Pittsburgh tests were compared. The results indicate that despite the use of different test methods, foam densities, formulations, fire retardants, and other additives, combustion toxicity data were generally considered comparable when similar endpoints were compared. Neither CO nor HCN appeared to be the primary cause of death due to the combustion products of flexible polyurethane foam, although they were probably contributory factors. Under conditions of oxidation and pyrolysis, polyurethane foams decomposed into a liquid polyol component and a “yellow smoke.” The polyol decomposed into CO, CO2, and low-molecular-weight hydrocarbons including ketones, ethers, and/or esters. At high temperatures (greater than 800°C), the “yellow smoke” decomposed into HCN and other nitrogen-containing compounds such as acetonitrile, acrylonitrile, and benzonitrile. Twice as much HCN was produced under pyrolytic conditions as in oxygen-rich atmospheres. Various amounts and types of other combustion compounds were produced, depending on the temperature and oxygen availability.

Phenolics: A Literature Review of Thermal Decomposition Products and Toxicity

1988 ◽  
Vol 7 (2) ◽  
pp. 201-220 ◽  
Author(s):  
P.K. Johnston ◽  
E. Doyle ◽  
R.A. Orzel
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Literature Review ◽  
Respiratory Rate ◽  
Sensory Irritation ◽  
Volatile Organics ◽  
Decomposition Products ◽  
Comprehensive Literature Review ◽  
Thermal Decomposition Products ◽  
Combustion Toxicity

A comprehensive literature review on the thermal decomposition products and combustion toxicity of phenolics is presented. The major decomposition products of phenolics appear to be CO, CO2, H2O, and methane. Smaller quantities of H2, formaldehyde, and other volatile organics, including phenol, methylphenols, and dimethylphenols, also appear to be produced. The types and quantities of thermal decomposition products and the temperatures at which they are produced depend on numerous factors, including the resin structure and formulation and the conditions of degradation. Phenolics produced products that were indicated to be more acutely toxic than other cellular plastics tested by one researcher and were described as “more toxic than wood” by another researcher. Carbon monoxide appears to be the major toxicant produced by the combustion of phenolics. Sensory irritation as indicated by reduced respiratory rate may be due to formaldehyde production; however, sensory irritation is lower than that produced by wood.

Analysis of Processes of Thermal Utilization of Biowaste

2018 ◽  
Vol 22 (5) ◽  
pp. 50-53
Author(s):  
A.V. Demin ◽  
R.Ya. Dyganova ◽  
N.N. Fakhreev
Keyword(s):  
Thermal Decomposition ◽  
Energy Efficiency ◽  
Phase Equilibria ◽  
Thermodynamic Calculation ◽  
Combustion Method ◽  
Combustion Products ◽  
Decomposition Products ◽  
Numerical Studies ◽  
Thermal Decomposition Products ◽  
Poultry Farming

The problems associated with the thermal utilization of droppings litter, which is formed at poultry farming facilities, are considered. The results of numerical studies for the biogas combustion method based on preliminary gasification of fuel are presented. A method for estimating the composition of thermal decomposition products based on the thermodynamic calculation of the chemical and phase equilibria is proposed. Calculated indicators of energy efficiency and environmental characteristics of combustion products are presented for a multi-zone combustion scheme.

Theoretical study on the formation of carbon disulfide and ammonia from thermal decomposition products of thiourea

2014 ◽  
Vol 13 (04) ◽  
pp. 1450022 ◽  
Author(s):  
Zerong Daniel Wang ◽  
Meagan Hysmith ◽  
Perla Cristina Quintana
Keyword(s):  
Thermal Decomposition ◽  
Carbon Disulfide ◽  
Density Functional ◽  
Basis Sets ◽  
Structural Isomer ◽  
Consecutive Reaction ◽  
Functional Theory ◽  
Decomposition Products ◽  
Thermal Decomposition Products ◽  
Hybrid Module

The formation of carbon disulfide ( CS 2) and ammonia ( NH 3) from the thermal decomposition products of thiourea has been studied with MP2, and hybrid module-based density functional theory methods (B3LYP, MPW1PW91 and PBE1PBE), each in conjunction with five different basis sets (6-31+G(2d,2p), 6-311++G(2d,2p), DGDZVP, DGDZVP2 and DGTZVP). The free energy changes and activation energies for all the five primitive reactions involved in the formation of CS 2 and NH 3 have been compared and discussed. The results indicate that CS 2 is most likely formed in a consecutive reaction path that consists of the addition of hydrogen sulfide ( H 2 S ) to isothiocyanic acid (HNCS) to generate carbamodithioic acid and subsequent decomposition of carbamodithioic acid. By contrast, thiocyanic acid (HSCN) as the structural isomer of isothiocyanic acid is not likely the source of CS 2.

Transport and condensation of soft a-C:H film thermal decomposition products

2003 ◽  
Vol 313-316 ◽  
pp. 460-464 ◽  
Author(s):  
A.E. Gorodetsky ◽  
R.Kh. Zalavutdinov ◽  
I.I. Arkhipov ◽  
V.Kh. Alimov ◽  
A.P. Zakharov ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Decomposition Products ◽  
Thermal Decomposition Products
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