To improve interactions between fibrous cellulose (FC) and polypropylene (PP), oxidatively degraded polypropylene (DgPP) and maleated polypropylene (MAPP) were studied as compatibilizers. Both compatibilizers had the same mechanism, using esterification between the OH group in FC and the reactive (gamma-lactone, acid, and maleic anhydride) groups in the compatibilizers. acid, However, the adhesion style with the ester bond was considerably different because of the arrangements of the reactive groups. DgPP had reactive groups at the polymer chain end, and the tensile behavior of the FC/PP/DgPP composite exhibited comparatively ductile behavior. However, MAPP had inner reactive groups, and the tensile behavior of the FC/PP/MAPP composite was quite brittle. Observation of these fracture surfaces suggested that the adhesion performance of the interface between FC and PP was strongly influenced by the arrangements of the reactive:e group. In addition, the performance was, influenced by the molecular weight of DgPP and by the content of maleic anhydride groups in MAPP. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 1835-1841, 2009