Effects of Morphology and Interfacial Strength on Mechanical Properties of Ternary Polypropylene Blends with Ethylene-Propylene-Rubber (EPR) and Talc: Molecular Dynamics Study
In order to clarify the influences of the morphology and interfacial strength on the microstructural deformation and micro-damage evolution process, a coarse-grained molecular dynamics (MD) simulation is conducted on a mesoscopic specimen of the thermoplastic polypropylene (PP) blended with the ethylene-propylene rubber (EPR) and talc under uniaxial tension. The studied morphologies are two types. The first morphology is composed of three independent phases of PP, EPR and talc. The second morphology consists of core-shell structure of EPR and talc in PP matrix. The first morphology shows that the micro-damage initiates at the interface between PP matrix and talc particle. Then, the micro void is generated there leading to the fibrils of the PP matrix and EPR particles. The second morphology indicates that the micro-damage initiates at the interface between EPR and talc. Meanwhile, the effects of the interfacial strengths of PP-EPR and PP-talc in the first morphology, and PP-EPR and EPR-talc in the second morphology on the macroscopic mechanical properties are further investigated. It appears that the elastic modulus is larger in the first morphology than that in the core-shell structure. It is also found that the maximum stress depends more strongly on the interfacial strength of PP-EPR than the morphological types. It is indicated that the absorbed strain energy is sensitive to both the morphology and the interfacial strength of PP-EPR.
JSMME 2 (11), 1369-1388, 2008