PET is a semicrystalline thermoplastic polyester used in many fields. For a variety of applications, however, it is necessary to impart desired properties by introducing specific functional groups on the surface. Aminolysis of PET fibers with diamines (1,2-diaminoethane, 1,6-diaminohexane, 3,6-dioxa-1,8-diaminooctane, and 4,9-dioxa-1,12-diaminododecane) gives amino functional groups on the surface. The effects of temperature, reaction time, diamine concentration, and solvent employed for the grafting were studied. The graft yield was observed to increase with temperature, reaction time, and diamine concentration. Aminolysis affects greatly the geometry and surface morphology of PET fibers as observed by scanning electronic microscopy and atomic force microscopy in tapping mode. A decrease of fibers diameter and an increase of surface heterogeneity and roughness due to chemical degradation is observed. Amino groups on the surface were used to prepare glycosylated fibers by reductive amination or amidation with different carbohydrates as maltose, maltotriose, and maltohexaose. The study reveals that the yield is dependent on the initial amino groups' surface concentration and the molar mass of the carbohydrate. These surfaces could benefit to a wide range of applications in the biomedical field. (C) 2007 Wiley Periodicals, Inc.