Fire Safety Science Digital Archive

The melting behavior of a number of polymers during burning, including thermoplastic and thermosetting polymers was studied by experiment and modeling. It was found that in a fire situation some thermoplastic polymers such as PP, LDPE, EVA-18 and PA6 melted significantly compared to PMMA for which the resulting melt vaporized rapidly and as a consequence there was little melt observed. On the other hand, some thermosetting resins generally did not melt or melted slightly, such as phenolic resin and epoxy resin. For the thermoplastics studied, the melting behavior affected the mass loss rates during the steady burning stage. The thermoplastics that melted significantly experienced much lower mass loss rates compared with the PMMA. This has been related to the pyrolysis mechanism of individual polymers. Generally, the polymers with a random pyrolysis process were more likely to lead to significant melting. The polymers undergoing depolymerization will lead to a rapid volatilization and therefore experienced much less melting. A numerical model for polymer burning was developed to include the melting behavior during burning. It was shown that the simulated results for the model considering melting behavior fitted in better with the cone calorimeter test results when compared to the model without considering the melting behavior.