The chemical modification of plasticized PVC films with amino thiophenol in mixtures of DMF/H2O has been studied. The degree of modification and the distribution of modified groups within the films were determined using Raman spectroscopy and FTIR-ATR. The amounts of plasticizer (bis-2-ethylhexyl phtalate, DOP) bleached out during the reaction and the amount of dimethylformamide (DMF) penetrated into the film were analysed in control reactions without the reactant using H-1 NMR spectroscopy and Raman spectroscopy. Reaction kinetics and surface selectivity of the modification reaction were compared with the corresponding reactions of PVC films without plasticizer. (C) 2003 Elsevier Science Ltd. All rights reserved.