The graft copolymerization of acrylic acid onto isotactic polypropylene has been investigated. The grafting was carried out using benzoyl peroxide initiator. Grafting is essentially a surface phenomenon and takes place, mostly, in amorphous region of the fiber. Emphasis, therefore, was placed on various pretreatment techniques for swelling of the fiber, viz, pretreatment with toluene and 1,1'2,2'tetrachloroethane, ultrasound, and photoirradiation. Process parameters, characterization study such as IR spectroscopy, TGA, and DTA, and properties such as tensile properties, melting temperature, dyeability towards basic dyes, and ion exchange properties were investigated. Benzene was found to be the most suitable solvent for initiator as against the acetone. Tenacity was found to be increased with increase in graft yield and reached to maximum at about 5% graft add-on, and then decreased with further increase in graft add-on. Proportionally, a converse effect was reported in the study of elongation to break. Thermal stability of polypropylene was found to be improved because of grafting. The grafted polypropylene also showed satisfactory dyeability toward basic dyes and also exhibits very good ion exchange properties. (c) 2006 Wiley Periodicals, Inc.