- Author
- Parker, W. J.
- Title
- Simultaneous Unzipping Model for the Decomposition of Cellulose and the Effect of Flame Retardants.
- Coporate
- National Bureau of Standards, Washington, DC
- Book or Conf
- University of Utah. Fire Prevention and Control: A Major Societal Problem. Polymer Conference Series. June 4-9, 1973, Salt Lake City, UT, 1-41 p., 1973
- Keywords
- fire prevention | fire suppression | flame retardants | decomposition | cellulose | unzipping | pyrolysis | weight loss | char | thermogravimetric analysis | flame retardant treatments | decomposition | unzipping | levoglucosan
- Abstract
- A simplified model for the decomposition of cellulose is presented along with the effects of flame retardants on this model. The basic hypothesis is that above 275 deg C cellulose decomposes through the similtaneous unzipping of all of its molecules, thus accounting for the constant rate of decomposition observed over most of the pyrolysis period. There is only one controlling reaction, namely unzipping, which dominates the pyrolysis at temperatures of concern in fires. The rate of decomposition is proportional to the number of molecules present which is essentially constant over most of the decomposition period. The lengths of the molecules decrease lineraly with time. After the oxygen links are broken during the unzipping process, 60 percent of the severed units are converted to levoglucosan and the remainder goes into char production. The action of the flame retardants is to increase the rate of decomposition and the amount of char produced. Direct action of the flame retardant on the levoglucosan causes the increase in char produced, and thus the reduction in flammability of the volatiles released.