Application of intumescent flame retardant containing aluminum diethyphosphinate, neopentyl glycol, and melamine for polyethylene

A novel intumescent flame retardant (IFR) composed of aluminum diethyphosphinate, neopentyl glycol, and melamine was incorporated into linear low-density polyethylene (LLDPE). The flame retardancy, thermal properties, and flame retardant mechanism of the materials were investigated. The chemical structures of composites were characterized by Fourier-transform infrared spectroscopy. Samples with thicknesses of 3 mm achieved the UL-94 V-0 rating during vertical burning tests, and the limiting oxygen index was 26.9% when 28 wt% IFR was introduced. The results of the thermogravimetric analysis showed that the addition of the IFR promoted the degradation and carbonization of the materials initially, increased the amount char residue, and improved the thermal stabilities of the composites at high temperatures. Cone calorimeter tests indicated that the peak value of the heat release rate was considerably reduced with the incorporation of the IFR. The digital photographs and scanning electron microscopy images of the char residue after cone calorimeter tests showed the formation of compact and thermally stable char layers on the polymer composites surfaces.