Formulation of novel fire retardant additives for biobased insulation material

Abstract

This study deals with the development of novel fire-retardant formulations to reduce the flammability of a low density rigid insulation panel made from hemp shiv glued with a thermosetting bio-binder. The objective is to identify possible substitutes to conventional fire-retardants, which are free from ammonium salts or boron compounds. The effect of the different treatments on the thermal decomposition of hemp shiv was analyzed by TGA/DA. The fire reaction of the insulation panel made of treated hemp shiv and bio-binder was characterized using the standardized cone calorimeter test. Two conventional treatments are used as references: a commercial ammonium phosphate/sulfate flame-retardant and a commonly used flame-retardant composition based on boric acid. Results showed that magnesium sulfate heptahydrate, phosphoric acid, sulfuric acid, functionalized silica particles and a combination of these could provide better fire retardancy effect than the conventional treatment based on boric acid. However, some treatments were not compatible with the selected panel formulation because they hindered the thermosetting binder polymerization leading to poor mechanical properties.