Effects of ZnO content on microstructure and properties of maleated EPDM/zinc oxide composites

Abstract

Properties of maleic anhydride-grafted ethylene–propylene–diene terpolymer/zinc oxide (MAH-g-EPDM/ZnO) composites with varying ZnO contents were characterized by the crosslink density, average grain size of zinc oxide, and ionomeric bond formation. The crosslink densities were measured by swelling method, the average grain sizes of ZnO were determined by X-ray diffraction (XRD), and the ionomeric bond formation was observed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). By increasing the ZnO content, the crosslink density increased, the average ZnO grain size increased, and level of the ionomeric bond formation tended to increase. The modulus increased and then reached to a plateau, whereas the elongation at break decreased and then reached to a plateau with increase in the ZnO content. From the experimental results, the proper ZnO content was found to be about 5 phr. Various crosslink types formed in the MAH-g-EPDM/ZnO composite were discussed.