ABS particles with core-shell structure and nano-CaCO3 particles were employed to modify hard PVC simultaneously.The phase morphology and fracture behavior of the composites were investigated by means of transmission electron microscope (TEM)

scanning electron microscope (SEM) and mechanical tests.Based on reasonable assumptions and material parameters obtained by the true stress-strain curve

finite element simulation employing the two-dimensional representative volume element model was carried out to explore the effects of ABS and CaCO3 particles on the fracture behavior of the composites.Results showed that ABS and CaCO3 particles have a synergistic toughening effect at nano-CaCO3 contents lower than 12 phr.The TEM observation revealed that the ABS particles deformed mainly by cavitation rather than interfacial debonding.The finite element analysis(FEA) results indicated that the blend yields when local yielding areas in the matrix begin to interconnect throughout the interstitial matrix between the particles.The predicted yield stresses for the PVC/ABS binary blend and the PVC/ABS/nano-CaCO3 ternary composite are consistent with experimental values.Moreover

the FEA results implied that both ABS and CaCO3 particles could toughen the PVC matrix

and the well-dispersed CaCO3 particles had a better toughening effect.If the CaCO3 particles are agglomerated

however

the large crevices between CaCO3 agglomerates and PVC matrix would initiate cracks at the interface and lead to decrease of mechanical properties.