CHANGE WITH EXTENSION OF MOLECULAR ORIENTATION OF HARD ELASTIC POLYPROPYLENE

Abstract

Change with extension of the molecular orientation of hard elastic polypropylene has been studied by use of x-ray diffraction, birefringence and polarized dye-fluorescent intensity distribution method. The degree of orientation of the c-axis oriented crystals decreases slightly with extension, which is inferred to be not due to the bending of crystals but due to the rotation because the sharpness of the crystalline diffraction remains unchanged under high extension, though the width becomes slightly larger. Birefringence decreases remarkably after yielding point because the negative contribution of the form birefringence due to the void formation. The change of the polarized dye-fluorescent intensity distribution showed that the molecular orientation decreases with extension, suggesting that dye-dichroism in this case was related to the crystalline orientation but not to the amorphous orientation.