Abstract

In order to improve the fire performance of composite materials, halogen-free flame retardant (diamonium hydrogen phosphate- DAP) was studied in an attempt to obtain UL-94 ratings for composite PVC-wood flour (PVC-WF). The fire behaviors and thermal stability properties were evaluated using UL- 94 vertical test, LOI test and thermogravimetric analysis (TGA). The UL- 94 test results show that V-0 rating is achieved at 1.5 wt% of DAP loading. The incorporation of halogene-free flame retardant (FR) increases the flame retardant properties as well as the amounts of charred residues protecting the mixture from further degradation. This assertion can be accepted when observing that the char residual of PVC-WF/DAP mixture at 600 oC is much higher than that of neat PVC-WF. The char layer may limit the amount of fuel available and insulate the underlying composite material from the flame and, thus, inhibit further degradation. This FR is a promising candidate that could replace the halogenbased flame retardant.