Synergistic effect of mesoporous silica SBA-15 on intumescent flame-retardant polypropylene

Mesoporous silica SBA-15 synthesized from Pluronic P123 and tetraethoxysilane was used as a synergistic agent on the flame retardancy of polypropylene (PP)/intumescent flame-retardant (IFR) system. Limiting oxygen index (LOI), UL-94 rating and thermogravimetric analysis were used to evaluate the synergistic effect of SBA-15 on PP/IFR system. It showed that PP/IFR system could reach V-0 with loading of SBA-15 ranging from 0.5 to 3 wt%, while without SBA-15 it had no rating at UL-94 test. The LOI value increased from 25.5 to 32.2 when the loading of SBA-15 was 1 wt%. The thermal stability of PP/IFR was improved in the presence of SBA-15 and the amount of the char residue at 600 degrees C was increased from 8.96 to 16.42 wt% when loading of SBA-15 varied from 0.5 to 5 wt%. Laser Raman spectroscopy (LRS) and scanning electron microscopy were employed to study the morphology of the char residue of PP/IFR system with and without SBA-15. Copyright (C) 2010 John Wiley & Sons, Ltd.