A novel phosphorus polyurethane FOAM/montmorillonite nanocomposite: Preparation, characterization and thermal behaviour

The preparation and characterization of the diphosphonium montmorillonite (DP-MMT) obtained by the intercalation of the quaternary diphosphonium salt [MeOOCCH2(Ph)2PCH2CH2P(Ph)2CH2COOMe]Br2 (DP-Br2) is reported with the aim to use it in the preparation of polyurethane foam-nanocomposites and in the study of their thermal behavior. DP-MMT was prepared by reaction of Dellite HPS in hot water with DP in 1:1 CEC ratio. DP-MMT was characterized by X-ray diffraction which showed a basal (d001) spacing of 1.90 nm versus 1.25 nm of the unmodified starting Dellite. The basal spacing value is consistent with a bilayer arrangement of intercalated chains. DP-MMT was characterized by 31P and 29Si NMR in the solid state. TGA curves showed that at about 400 °C the weight loss in DP-MMT is ca. 18%. DP-MMT was then used in polyurethane rigid foam (PUR) synthesis (5 wt.%). DP-MMT and commercial ammonium-modified MMT (Cloisite®30B) as well as unmodified MMT (Dellite HPS) were used as filler for PUR foams, together with Al-hypophosphite. Thermal stabilities were compared.