Flammability of Polymers

Assignment B Flammability of polymers Combustion and Decomposition of polymers Most polymers atomic number 18 made up of smaller hydrocarbons repeat to form a yearn chain molecule. In heat up generally the passe-partout polymer remains mostly in inconstant. The king-size polymer molecules decompose via pyrolysis (Thermochemical decomposition without oxygen) creating passing reactive free radicals which in turn help rifle down more of the long chain. In the heat the molecules perpetually decompose in the condensed microscope stage ( upstanding or liquid) into smaller scummy molecular weight, highly volatilizable molecules. These small molecules vaporize and gravel fire easily if the temperature rises in a higher place fervor temperature. Decomposition gear up out run as long as the temperature is enough to continue thermal decomposition and in turn hightail it the flames with volatile compounds. An example of the decomposition of a polymer (polyethene) to smaller molecules is shown on a lower floor (derived from plat examples on Sciencedirect.com and Uclan.ac.

uk): Initiation - polymer chain [pic] + HEAT file name extension (many possible combinations) [pic] + [pic] [pic] + CH2=CH2 [pic]+ [pic] Termination- (Gas phase) Volatile species organize (again many possible forms) CH2=CH2 CH2=CH-CH3 CH3-CH3 [pic] These smaller molecules essentially fuel the polymer to shorten more once ignited. The flame heats the polymer causing it to decompose further , relinquish more fuel for the flames. This! creates a self sustaining hit the ceiling cycle. When the flames burn longer and pull in hotter larger molecules will r all(prenominal) their ignition temperature and burn creating a fiercer fire. COMBUSTION CYCLE DIAGRAM The diagram above shows the combustion cycle of a polymer. The phase boundary shows what narrate each part happens. The pyrolysis of the polymer happens in the condensed phase as a solid or a liquid. This is the state in which the heat...If you lack to tug a full essay, order it on our website: OrderCustomPaper.com

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