- Author
-
Myers, R. E.
|
Dickens, E. D., Jr.
|
Licursi, E.
|
Evans, R. E.
- Title
- Ammonium Pentaborate: An Intumescent Flame Retardant for Thermoplastic Polyurethanes.
- Coporate
- Goodrich (B. F.) Research and Development Center, Brecksville, OH
- Journal
-
Journal of Fire Sciences,
Vol. 3,
No. 6,
432-449,
November/December 1985
- Keywords
-
flame retardants
|
thermal decomposition
- Abstract
- Ammonium pentaborate (APB) is shown to be an effective intumescent, char-forming additive for thermoplastic polyurethanes (TPU). As little as 5 to 10 parts of APB, added to a flame retarded TPU, provides a 7 to 10-fold improvement in burn-through resistance. The APB/TPU char is characterized by its glassy, multicellular structure which provides virtually instanteous thermal protection to heat-sensitive substrates and is able to resist thermo-oxidative degradation. In contrast to its behavior in polyurethanes, APB is found to be somewhat less effective as an intumescent additive for several non-urethane polymers such as natural rubber, polyester resin, polyamide and polyvinyl chloride. A mechanism is proposed to account for the unique nature of the APB/TPU system. It is suggested that, via a series of chemical reactions, APB redirects the thermal decomposition of the polyurethane thereby producing less volatiles and increased char.