Safety Concerns in dealing with Hazards involving Polymeric materials
Chemistry plays a significant role in modern society and specifically Organic Chemistry contributes to the Economy and Development of Nations. The uniqueness of Organic Chemicals originates from the special property of Carbon atom arising out of SP3 Hybridization and the possibility of Carbon atom linking with another carbon atom or other atoms, forming compounds or Functional groups which can again link with one another forming lengthy chain, called polymers. The property of the polymers can be engineered to cater to the specific need, by introducing proper groups / elements like OH, NO2, CN, F, or Cl. Physical parameters like Hardness, Melting point, Thermal conductivity, Electrical resistance and Chemical properties like Flammability, Detonatability, Flame retardancy can be modified by selecting suitable groups while producing the monomer and by conditioning the polymerization process, thus yielding a variety of materials for the use of society.
But the unfortunate side effects are the hazards involved in manufacture, transportation, storage and handling them like: Explosion, Fire hazard, Toxicity, Pollution and Environmental degradation as these Polymers are made up of Carbon and other hazardous materials like F, Cl, NO2, CN etc. The Fire Service and EH&S Personnel must be aware of the potential hazards, the hazardous materials encountered in their area of control and the means of mitigating the incident and very importantly the ways and means of self protection.
Safety Concerns in dealing with Hazards involving Polymeric materials
The Organic polymers find their use in almost every walks of modern life- be it clothing, furniture, automobiles, house interiors, house hold articles, Piping systems, computers etc. The manufacture, transport and storage of the products as well as the raw materials involve hazards like accidents, spillage, fire and environmental Pollution. Though these industrial polymers are not explosive in nature, they do burn at elevated temperature encountered in any fire mishap. The general characteristics of the polymers while burning are: melting of the polymer, depolymerization, volatilization of the monomers, burning / explosion of the vapors and emission / spreading of products of combustion. If the polymeric substance involved in the mishap is large, so is the CO formation due to partial combustion resulting from reduced Oxygen supply. There is a possibility of asphyxiation also because of the depletion of Oxygen during the fire mishap. A few examples are discussed below.
PVC
PVC, Poly vinyl Chloride having Carbon, Hydrogen , Nitrogen (in the form of Cyanide group) and plasticizers like Di Octyl Phthalate, is a very common material finding use in many Plastic articles, to name a few: Piping Systems, casing of electric wires, house hold articles and building materials. These materials, as well their raw material- Ethylene Chloride and the intermediate VCM (Vinyl Chloride Monomer, CH2=CH Cl), are being produced, transported, stored in large quantities, posing severe hazards. VCM is a highly hazardous material, explosive as well as carcinogenic. On thermal decomposition, PVC produces CO2, CO, soot (C), HCl gas, polychlorinated dibenzofurans and polychlorinated dibenzo-p-dioxins (as cited in Chemistry of Some Polymeric Materials, p. 688). All these are dangerous: CO is deadly poisonous, HCl gas is highly corrosive affecting lungs, CO2 is asphyxiating, the dioxins have acute as well as chronic ill effects and soot adsorbs these dioxins and ingests them into human body. PVC normally contain some un polymerized VCM. The VCM volatilizes at the elevated temperature encountered in any fire mishap, and it is very dangerous to inhale this as it is a known carcinogen (as cited in Chemistry of some polymeric materials, P688).
Polyacrilonitrile
Poly acrilonitrile is the polymer of Vinyl Cyanide, commonly known as Acrilonitrile, having Carbon, Hydrogen and Nitrogen (Cyanide group) in it’s molecule along with significant amount of Plasticizers. It is used in the manufacture of textiles, plastics and rubber (P689). Though it is fairly stable thermally, undergoes thermal decomposition at elevated temperatures, producing CO2, CO, soot and HCN. Tsuchiya (1977) asserts under smoldering conditions, say 300 to 400 OC, where there is limited supply of Oxygen, the concentration of CO as well as HCN is likely to be fatal (p. 272, 275, 276). Hathaway et al. 1991 reports “270 ppm of HCN is fatal after 6 to 8 minutes, 181 ppm after 10 minutes and 135 ppm after 30 minutes of inhalation”.
It is essential the personnel, attending to the mishap caused by fire or explosion involving such hazardous Polymers, should be aware of the modalities of handling the situation, ensure selection of relevant fire extinguishers, and use appropriate personnel protective equipments like Gas mask, Oxygen cylinder, Fire resistant clothing / Aprons to protect themselves and to effectively mitigate the effects of the mishaps.
But the unfortunate side effects are the hazards involved in manufacture, transportation, storage and handling them like: Explosion, Fire hazard, Toxicity, Pollution and Environmental degradation as these Polymers are made up of Carbon and other hazardous materials like F, Cl, NO2, CN etc. The Fire Service and EH&S Personnel must be aware of the potential hazards, the hazardous materials encountered in their area of control and the means of mitigating the incident and very importantly the ways and means of self protection.
Safety Concerns in dealing with Hazards involving Polymeric materials
The Organic polymers find their use in almost every walks of modern life- be it clothing, furniture, automobiles, house interiors, house hold articles, Piping systems, computers etc. The manufacture, transport and storage of the products as well as the raw materials involve hazards like accidents, spillage, fire and environmental Pollution. Though these industrial polymers are not explosive in nature, they do burn at elevated temperature encountered in any fire mishap. The general characteristics of the polymers while burning are: melting of the polymer, depolymerization, volatilization of the monomers, burning / explosion of the vapors and emission / spreading of products of combustion. If the polymeric substance involved in the mishap is large, so is the CO formation due to partial combustion resulting from reduced Oxygen supply. There is a possibility of asphyxiation also because of the depletion of Oxygen during the fire mishap. A few examples are discussed below.
PVC
PVC, Poly vinyl Chloride having Carbon, Hydrogen , Nitrogen (in the form of Cyanide group) and plasticizers like Di Octyl Phthalate, is a very common material finding use in many Plastic articles, to name a few: Piping Systems, casing of electric wires, house hold articles and building materials. These materials, as well their raw material- Ethylene Chloride and the intermediate VCM (Vinyl Chloride Monomer, CH2=CH Cl), are being produced, transported, stored in large quantities, posing severe hazards. VCM is a highly hazardous material, explosive as well as carcinogenic. On thermal decomposition, PVC produces CO2, CO, soot (C), HCl gas, polychlorinated dibenzofurans and polychlorinated dibenzo-p-dioxins (as cited in Chemistry of Some Polymeric Materials, p. 688). All these are dangerous: CO is deadly poisonous, HCl gas is highly corrosive affecting lungs, CO2 is asphyxiating, the dioxins have acute as well as chronic ill effects and soot adsorbs these dioxins and ingests them into human body. PVC normally contain some un polymerized VCM. The VCM volatilizes at the elevated temperature encountered in any fire mishap, and it is very dangerous to inhale this as it is a known carcinogen (as cited in Chemistry of some polymeric materials, P688).
Polyacrilonitrile
Poly acrilonitrile is the polymer of Vinyl Cyanide, commonly known as Acrilonitrile, having Carbon, Hydrogen and Nitrogen (Cyanide group) in it’s molecule along with significant amount of Plasticizers. It is used in the manufacture of textiles, plastics and rubber (P689). Though it is fairly stable thermally, undergoes thermal decomposition at elevated temperatures, producing CO2, CO, soot and HCN. Tsuchiya (1977) asserts under smoldering conditions, say 300 to 400 OC, where there is limited supply of Oxygen, the concentration of CO as well as HCN is likely to be fatal (p. 272, 275, 276). Hathaway et al. 1991 reports “270 ppm of HCN is fatal after 6 to 8 minutes, 181 ppm after 10 minutes and 135 ppm after 30 minutes of inhalation”.
It is essential the personnel, attending to the mishap caused by fire or explosion involving such hazardous Polymers, should be aware of the modalities of handling the situation, ensure selection of relevant fire extinguishers, and use appropriate personnel protective equipments like Gas mask, Oxygen cylinder, Fire resistant clothing / Aprons to protect themselves and to effectively mitigate the effects of the mishaps.
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