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 [MeOOCCH(2)(Ph)(2)PCH(2)CH(2)P(Ph)(2)CH(2)COOMe]Br(2) (DP-Br(2)) 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 (d(001)) 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 (31)P and (29)Si NMR in the solid state. TGA curves showed that at about 400 degrees 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 (R) 30B) as well as unmodified MMT (Dellite HPS) were used as filler for PUR foams, together with Al-hypophosphite. Thermal stabilities were compared.