Characterization of PP/EPDM/HDPE Ternary Blends: The Role of Two EPDM with Different Viscosity and Processing Method

Abstract

In this work, PP/EPDM/HDPE ternary blends were applied. Morphologies and melt crystallization behavior, rheological property and mechanical properties of these blends were studied by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), dynamic rheology analysis and mechanical properties tests. It was found that the viscosity of EPDM had greatly effect on the morphology of PP/EPDM/HDPE blends. The more perfect encapsulation structure (core of HDPE and shell of EPDM) can be formed in the PP/EPDM/HDPE 70/20/10 blend with lower viscosity EPDM2 and the Notched Izod impact strength of blend was greatly improved. The melting points of PP and HDPE in PP/EPDM1/HDPE blend decrease with the content of phenolic resin varying from 0.5 wt% to 1.5 wt% in two processing methods (the direct extrusion and lateral injection method). The ternary blends of PP/EPDM/HDPE prepared by two methods with different content of phenolic resin showed different rheological behavior: The storage (G’) and loss modulus (G'’) of blends obtained by the direct extrusion are slightly higher for low frequency region than that by the lateral injection technique in general opinion. The tensile strength of PP/EPDM1/HDPE blend added 0.5 wt% phenolic resin in direct extrusion is highest.

Keywords:

• Core-shell morphology
• Mechanical property
• Melt behavior
• Rheological property
• Ternary blends

ACKNOWLEDGMENTS

The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (Contract No. 50903050 and 20874066).

Notes

Note: Tm’, Tm stands for the starting temperature of molten peak and the peak temperature; b and c represent the direct extrusion and lateral injection technique, respectively.