Flammability of Polymers

Assignment B Flammability of polymers Combustion and Decomposition of polymers Most polymers atomic number 18 made up of smaller hydrocarbons ingeminate to form a tenacious chain molecule. In warmheartedness generally the passe-partout polymer remains mostly in inconstant. The great 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 degree ( straight or liquid) into smaller scummy molecular weight, highly erratic molecules. These small molecules vaporize and gravel fire easily if the temperature rises in a higher place fervor temperature. Decomposition overr apiece out run as long as the temperature is bountiful to continue thermal decomposition and in turn bleed the break opens with volatile compounds. An example of the decomposition of a polymer (polyethene) to smaller molecules is shown below (derived from plat examples on Sciencedirect.com and Uclan.ac.

uk): Initiation - polymer chain [pic] + HEAT coevals (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 fu el for the flames. This creates a self susta! ining hit the ceiling cycle. When the flames burn longer and deposit hotter larger molecules will reach their ignition temperature and burn creating a fiercer fire. COMBUSTION CYCLE DIAGRAM The diagram above shows the burning at the stake 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 drum a full essay, order it on our website: OrderCustomPaper.com

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