Synergistic effects of sepiolite on intumescent flame retardant polypropylene

Abstract

Abstract. In this paper, the effects of sepiolite as a synergistic agent on the flame retardancy of intumescent flame retardant polypropylene (PP/IFR) were studied using the limiting oxygen index (LOI), the UL-94 test, thermogravimetric analysis (TGA), laser Raman spectroscopy (LRS), cone calorimeter test (CCT) and scanning electron microscopy (SEM), and the IFR system mainly consisted of the ammonium polyphosphate modified with γ-aminopropyltriethoxysilane coupling agent, melamine and dipentaerythritol. The results from the LOI and UL 94 tests show that sepiolite added to the PP/IFR system has a synergistic flame retardant effects with the IFR system. The TGA results reveal that sepiolite enhances the thermal stability of the PP/IFR composite and increases the char residue formation. The cone calorimeter results indicate that the heat release rate, mass loss rate, total heat release and average specific extinction area of the PP/IFR/sepiolite composite decrease in comparison with the PP/IFR composite. The LRS measurements provide useful information on the carbonaceous microstructures. The morphological structures observed by SEM have demonstrated that sepiolite promote the formation of the reinforced and homogeneous char barrier on the surface of the composites. Simultaneously, the Young's modulus and flexural modulus of the PP/IFR composites are also much better improved with the increase of sepiolite added.

Effect of phosphorous-containing modified poly(vinyl alcohol) on the mechanical and flame retardant properties of polypropylene

“…From the curves it can be observed that neat MPP showed one weight loss step between 400 and 500°C, while all blends displayed an additional degradation step in the 200-300°C temperature range. This additional weight loss process has been attributed to the decomposition of the additives initiated by thermal dehydration reactions, as confirmed by massive water evolution detected through mass spectrometry [11]. This step appeared at a slightly lower temperature in B15 with respect to the other blends, probably due to its higher content of -OH groups.…”

Synergistic Effect of Phosphorus-Containing Montmorillonite with Intumescent Flame Retardant in Polypropylene

“…[1][2][3] Nevertheless, IFR's relatively low flame retardant efficiency impedes their actual commercial applications. To overcome this disadvantage, many synergists, including zeolites, [4,5] iron powder, [6] fumed silica, [7] rare earth oxide, [8] sepiolite, [9] ultrafine full-vulcanized powdered rubber, [10] montmorillonite (MMT), [11] etc., have been introduced to improve the flame retardant efficiency of IFR.…”

Synergistic Effect of Organic Vermiculite on the Flame Retardancy and Thermal Stability of Intumescent Polypropylene Composites

“…Among the synergistic agents, silicate has attracted great attention in recent years because of its low cost, easy availability and high efficiency. Up to now, the study on synergistic effects of silicate have mainly focuses on montmorillonite, kaolin, sepiolite and silica, [5][6][7][8][9][10][11][12] but little investigation has been made on vermiculite (VMT). [13] The VMT is a 2:1 layer type of the mica group silicates which consists of octahedrally coordinated cations, typically Mg, Ca, Al, and Fe, sandwiched by tetrahedrally coordinated cations, typically Si and Al.…”