Three commercially available adhesion promoters based on silanes were used to modify montmorillonite. The short and highly reactive 3-aminopropyltrimethoxysilane (APS) is not able to expand the silicate layers. 3-(2-aminoethyl)aminopropyltrimethoxysilane (AEAPS) and 3-(6-aminohexyl)aminopropyltrimethoxysilane (AHAPS) can be used for a cation exchange reaction in montmorillonite, but the layer distance in the modified clay material is rather low, especially for AHAPS. So mixtures with surfactants were used to modify montmorillonite. With dimethyldistearylammonium chloride as comodifier three ways of preparation of silanized organoclay were tested. Two of them lead only to a rather low content of silane adhesion promoter according to elemental analysis. After compounding with PP-g-MA a reaction of the primary amino group of the silane with PP-g-MA can be shown by IR-spectroscopy. Some samples were made in an amount sufficient for preparing composites on a Berstorff extruder and specimens were made by injection moulding. These were tested according to CAMPUS conditions showing increased mechanical properties in comparison to not silanized montmorillonite nanocomposites, although TEM pictures prove a worse distribution of clay.