The silylation of borosilicate with APTS ((gamma-aminopropyl)triethoxysilane) is studied as a tool to improve zeolite incorporation in PI (polyimide) films. Among other experimental parameters, a quantification of the zeolite outer surface silanols is performed in order to determine the most appropriate silylation conditions. Xylene sorptions, NMR (nuclear magnetic resonance) spectroscopy, and measurements of the specific surface of the zeolites were performed to characterize the silylation. Finally, the silylated zeolite was incorporated in PI films on which tensile strength, density, and xylene sorption were measured.