A TGA study correlating polymer characteristics with smoke and flammability properties of polyester and phenolic resins

Because of the unacceptable amount of smoke produced from styrene cross-linked polyester composites, when tested for specific optical density of smoke generated by solid materials (ASTM E662), phenolic resins are currently under investigation as an alternative to polyesters in marine applications. Thermogravimetric analysis (TGA), NBS smoke chamber tests, oxygen index tests, flame spread tests, and toxic gas production tests have been used to study the fire and flammability characteristics of two styrene cross-linked polyester resins, Vibrin F1029 and Hetron 692TP, and three resol phenolic resins, J2018L, OCFHJ1 and Plenco 11956. Results of thermogravimetric analyses on the phenolic and polyester resins, in both air and nitrogen, indicate that the phenolic resins are superior to the polyester resins from a "smoke and flammability" point-of-view. That is, the phenolics are more stable thermally, produce less smoke, have a higher oxygen index, have a lower flame spread rating and produce less toxic gas than the polyester resins. The higher thermal stability and lower smoke release of the phenolic resins relative to the polyester resins is discussed in terms of the degradation mechanisms and degradation products of these resins.