The Fracture Behavior For The Composites Of Polypropylene-wollastonite-polyolefin Elastomer

Fracture behavior of polymers is an important factor for using and choosing polymer materials. There are many methods to study the fracture behavior of polymers, such as linear elastic fracture mechanics and J-integral analysis. A new method, the essential work of fracture (EWF) method, has gained attention recently. This method shows its advantages in studying the fracture toughness of ductile polymeric materials and has been investigated and applied by increasing number of researchers.This paper investigated the fracture behavior of PP-wollastonite-POE composites under low strain rates. It also studied the relationship between the microstructure of the material and the fracture parameters. The theoretical foundation of this work is the EWF method. The effect of the wollastonite content on the fracture parameters was discussed. The optimum wollastonite content to achieve the maximum We changes with the particle size of the wollastonite, suggesting that there are an optimum particle size as well as wollastonite content for the toughness of the composite. The effect of wollastonite on the fracture toughness was mainly achieved through their influence on the properties in necking and tearing processes after yielding, while the effect of wollastonite on the plastic deformation energy was mainly achieved through their influence on the properties before yielding. The effect of wollastonite content on mechanical and crystallization properties of the composite was studied. The results show that the impact strength decreases as the wollastonite content increases. However, the composition with high impact strength has lower specific essential energy of fracture and lower long-term fracture resistance, indicating that EWF is a better indicator of long-term fracture properties than the impact strength. DSC results show that the presence of wollastonite hinders crystallization of the PP.