Graft copolymers of polypropylene functionalized with 6 wt% of acrylic acid (PPAA) and a liquid-crystalline polyester (SBH) derived from sebacic acid, 4,4＇-dihydraxybiphenyl and 4-hydroxybenzoic acid, prepared under various conditions, as well as fractionation products of the graft copolymers were investigated by infra-red spectroscopy. The grafting was followed by measuring changes in the amount of carboxylic and aliphatic-aromatic eater groups.