The effect of phosphorus containing polyol and layered double hydroxides on the properties of a castor oil based flexible polyurethane foam

In this work the effect of the addition of a phosphorus containing polyol (E560) and different type of layered double hydroxides (LDH) to flexible polyurethane foams synthesized with a castor oil based polyol (LB50) is reported. A carbonate intercalated commercial synthetic hydrotalcite (LDH-CO3) and modified LDH with intercalated hydrogen phosphate and bis(2-ethylhexyl) hydrogen phosphate (LDH-HPO4 and LDH-HDEHP, respectively) were used. The density and the compression force deflection values of the foams increased with the addition of E560, while the effect of the different LDH depended on their dispersion degree, which was analyzed by X-ray diffraction. It was found by thermogravimetric analysis that E560 catalyzed the first degradation stage whereas LDH, especially those modified with phosphorus, showed a barrier effect which delayed the thermal degradation with respect to unfilled foams containing E560. It was also observed by pyrolysis combustion flow calorimetry that the combination of E560 with LDH led to decrease the total heat release and heat release capacity comparing to foams fully synthesized with LB50. Both E560 and LDH resulted also to decrease the peak heat release rate separately in both stages of degradation.