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

The charging of maleic anhydride (MA) and dicumyl peroxide (DCP) into polyp ropylene 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 t he amount of grafted anhydride was dependent on the amount of MA and DCP ch arged into the polypropylene matrix. The presence of grafted succinic anhyd ride was shown by FT-IR spectroscopy and its amount was determined through a calibration curve derived from standard samples. The effect of swelling d ue 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 a nd through calorimetric analysis. (C) 2000 Elsevier Science Ltd. All rights reserved.