Structure and mechanical properties of PP/EPDM/attapulgite ternary blends

Polypropylene(PP)/ethylene-propylene-diene copolymer (EPDM)/fibrillar silicate attapulgite (AT) ternary blends were first prepared via the two-step melt blending process, by which the AT was blended with EPDM prior to compound with PP. Structure and mechanical properties of the blends were investigated. According to the analysis of TEM and DMA test, it was concluded that as for PP/EPDM/AT ternary blends, the typical "sea-island" morphology was observed, and the morphology of encapsulated structure like sandbag was formed in PP matrix besides neat EPDM dispersion domain, where EPDM encapsulated fibrillar silicate AT. The most-odds diameter (D_m), the number-average diameter (D_n) and the weight-average diameter (D _w) of dispersed particles decreased with increasing EPDM. PP/EPDM/AT ternary blends showed higher yield strength and dynamic modulus than the corresponding PP/EPDM binary systems due to the reinforcement of AT. PP/EPDM/AT ternary blend (100/20/5) possessed the balanced yield strength (21.9MPa) and impact strength (47.7 kj·m^-2), relative to 23.0MPa and 9.4kJ·m^-2 of PP. The micromechanical deformation process-mainly debonding of dispersed particles and shear yielding was mainly responsible for impact resistance of the ternary blends.