Gamma radiation induced maleation of polypropylene using supercritical CO2:: preliminary results

The charging of maleic anhydride (MA) and dicumyl peroxide (DCP) into polypropylene matrices has been carried out by CO:! in supercritical conditions. The grafting of MA into polymer chains was done through gamma irradiation in CO2 atmosphere (0.1MPa, 25 degrees C). The grafting was successful and the amount of grafted anhydride was dependent on the amount of MA and DCP charged into the polypropylene matrix. The presence of grafted succinic anhydride was shown by FT-IR spectroscopy and its amount was determined through a calibration curve derived from standard samples. The effect of swelling due to supercritical CO2, maleic anhydride grafting and gamma irradiation on the molecular structure and molecular weight of the modified polypropylene has been investigated through dynamic-mechanical tests in the melt state and through calorimetric analysis. (C) 2000 Elsevier Science Ltd. All rights reserved.