Grafting Acrylic Acid onto Pre-irradiated Polypropylene by Reactive Extrusion

Polypropylene functionalized with acrylic acid(PP-g-AA)was prepared by coupling electron beam(EB)pre-irradiation treatment with reactive extrusion process.The grafting samples were characterized by chemical titration,FTIR,polarized light microphotographs,DSC and WAXD.The study showed that grafting degree(Gd)increased with increasing irradiation dose and then leveled off;the Gd increased linearly with the AA concentration rising.It was observed that crystallization temperature of the grafted sample increased and crystallite size decreased,which can be attributed to the heterogeneous nucleating action of grafting chain.The MFR and mechanical properties measurements proved that serious degradation of PP occured in the stage of pre-irradiation and extruding process.Meanwhile,a mechanism of grafting reactions was proposed tentatively.