Composite films are obtained by casting aqueous dispersions obtained by admixture of PVAc or styrene-acrylic latexes with aluminium or iron polyphosphate powders. Film extraction with solution of aqueous EDTA (a solvent for polyphosphate) yields a dense polymer film, but using a polymer solvent (chloroform) a porous monolithic solid is obtained. Composite and solvent-extracted films were characterized by SEM coupled to energy dispersive X-ray analysis, and by Raman microspectrophotometry. The results from morphological, spectral and gravimetric experiments show that the cast films are bicontinuous, indicating a strong compatibility of the organic and inorganic phases. This is assigned to ionic bonds at the interfaces, in which aluminium ions act as bridging groups.