Synthesis and characterization of thermoplastic composites filled with γ‐boehmite for fire resistance

This paper explores the use of boehmite as a fire retardant in low‐density polyethylene and polyamide 6. The structure and morphology of the filler are characterized by X‐ray diffraction and scanning electron microscopy. The water content of our boehmite is estimated about 30% by thermogravimetric analysis. The filler/matrix interactions in nanocomposites are investigated by means of thermo‐physical measurements: differential scanning calorimeter and thermogravimetry. The resulting morphology shows particles individually dispersed in the matrix. The fire tests present a fire‐resistance effect at low filler content despite a different behavior as a function of the matrix. For instance, with only 2% volume of boehmite, the burning time of LDPE composite is significantly increased by 15%. At the same filler content in PA6, the burning time is solely increased by 4.5%. On the other hand, the limiting oxygen index is increased by +7.0% (only 2.6% with LDPE composites).