| Abstract: | The deformation mechanism for linear low-density polythylene (LLDPE) has been studied by electron microscopy, infrared spectroscopy, and pulsed nuclear magnetic resonance. Morphologically, the lamellae in the polar region of a spherulite are aligned in parallel to the drawing direction and then unfolded into microfibrils with drawing. The lamellae in the equatorial region are curved, corrugated, and unfolded partially. Actually, microfibrils are formed with transformation of both lamellae and some amorphous molecules throughout the drawing. Restraint of molecular mobility for the amorphous region increases with drawing, but mobility for the immobile region (lamellae and microfibrils) remains constant. Orientation of the trans-methylene sequences in amorphous regions proceeds with extension. These results can explain the changes of the s-s curve behavior. |
