Deformation-induced crystalline structure evolutions of isotactic poly-1-butene

Abstract

The deformation-induced crystalline structure evolutions of isotactic poly-1-butene (iP-1-B) during uniaxial stretching at different temperatures (45 and 75 °C) were investigated with in situ wide-angle X-ray scattering (WAXS) technology. The form I of iP-1-B was employed in this study. The obtained data on structure evolutions revealed that orientations would occur when the applied stress reached a critical value, while the orientation mechanisms are different at the two investigated temperatures. The crystallinity at 75 °C declines fast during deformation, and the orientation is caused by the melting disparity between the crystals parallel and perpendicular to the stretching direction. The high crystalline content during stretching at 45 °C maintains throughout the tensile process and the rotation of crystalline blocks results in the orientation. A brief schematic diagram was given to clarify the routes of orientation at the two temperatures.