Lv P, Wang Z, Hu Y, Yu M (2008) Effect of metallic oxides in polypropylene composites containing melamine phosphate and pentaerythritol. Plastics Rubber and Composites 37(7), 311-318. [In English]

Web link: http://dx.doi.org/10.1179/174328908x314325

Keywords:

Metallic oxide; Polypropylene; Intumescent flame retardant; Char; Morphology; Nano-indentation; fire retardant polymers; intumescent systems; thermal-degradation; ester; formation; mechanism; mixtures; fillers

Abstract: The effect of metallic oxide in the intumescent flame retardant (IFR) polypropylene (PP) composites containing melamine phosphate (MP) and pentaerythritol (PER) is studied. The flammability of the composites was characterised by limiting oxygen index (LOI), UL-94 and cone calorimeter tests. It is found that, in the case of the IFR composites containing metallic oxides, all of them have higher LOI values than the composites without them, and composites with 1% zirconium dioxide (ZrO(2)) or 1% dichromium trioxide (Cr(2)O(3)) can achieve the V-0 rating. The cone calorimeter results show that the composite containing 1% Cr(2)O(3) has a lower heat release rate than the IFR composite, and the incorporation of titanium dioxide (TiO(2)), lanthanum trioxide (La(2)O(3)), zirconium dioxide (ZrO(2)) and Cr(2)O(3), leads to a major decrease in the peak CO emission. Scanning electron microscopy reveals that the surface of the intumescent char is strongly modified in the presence of the metallic oxide. Moreover, the mechanical properties of the composites and the intumescent chars are studied.