OS15-1-2 Deformation Behavior and Molecular Orientation in Polyolefinic Thermoplastic Elastomers

Abstract

The deformation process in polyolefinic thermoplastic elastomers (TPE) prepared by dynamic vulcanization of iPP/EPDM blends was investigated by FTIR spectroscopy and wide angle x-ray diffraction. The molecular orientation of the EPDM domains in TPE was higher than that of iPP matrix in TPE at the high uniaxial strain whereas the molecular orientation of the pure iPP at the high strain was strong. The molecular and crystallite orientation of EPDM in TPE was released whereas the orientation of iPP in TPE remained when the strain was released. The deformation of EPDM domains showed the elastic deformation and dominated the TPE deformation at the high uniaxial strain, after the fracture of iPP matrix phase occurred in the equatorial iPP region neighboring elongated rubber domains at the low strain. The elasticity of TPE was caused by the EPDM domains.