In this investigation, modification of polypropylene (PP) with an objective to obtain packaging film with improved gas barrier properties has been studied. The chemical reaction of PP resin with hexamethylene diisocyanate and toluene diisocyanate was monitored by Fourier transform infrared spectroscopy, wherein the appearance of new peaks at 3333 cm(-1) for -N-H stretching, 1620-1641 cm(-1) for -(C=O)-NH stretching and 1552-1578 cm(-1) corresponding to -N-H bending in an amide moiety was observed for both the modified PP films. Films of excellent clarity and uniform thickness were obtained by the extrusion of cross-linked polypropylene. The barrier, mechanical, optical, and thermal properties of the modified PP films were studied. The results clearly indicated significant changes in gas barrier and mechanical properties. Food compatibility of the films was evaluated by overall migration in to different food simulants. (C) 2010 Wiley Periodicals, Inc. Adv Polym Techn 28:233-245,2009; Published online in Wiley InterScience (www.interscience.wileycom). DOT 10.1002/adv.20168