Synchrotron Ultrasmall-Angle X-ray Scattering Studies on Tensile Deformation of Poly(1-butene)

Abstract

Real-time synchrotron ultrasmall-angle X-ray scattering measurements were performed during the tensile deformation of crystalline phase I poly(1-butene) (P1B). For comparison, high-density polyethylene (HDPE) was also studied. During tensile deformation, the main contribution to the scattering intensity is due to platelike cavities in the case of P1B, whereas very rarely such cavity scattering is observed in the case of HDPE. At small deformations, the platelike cavities were found to occur only in those lamellae whose normals are perpendicular to the stretching direction. This effect is due to the blocky substructure of the crystalline lamellae. At large orientations these cavities reorient turning their normal gradually perpendicular to the stretching direction; this effect is due to the preferential orientation of the polymer chains. Nevertheless, a fraction of the cavities with their normal parallel to the stretching direction are preserved at large deformation. It was found that there exists a critical thickness of cavities below which no stable cavity could be observed. The strain of the cavities with their normal parallel to the stretching direction is proportional to the macroscopic strain but with smaller values.

Uniaxial deformation of overstretched polyethylene: In-situ synchrotron small angle X-ray scattering study

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Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

“…Despite active researches focusing on the cavitation triggered around the yield point, an agreement on explaining the cavitation mechanism is still not yet reached. Two general but distinctly different concepts emphasizing different locations of cavitation initiation in a spherulite have been separately proposed Galeski et al. suggested the nucleation and growth of cavities in the amorphous phase between two adjacent crystalline lamellae in the equatorial region of a spherulite while Men et al.…”

Critical roles of molecular dynamics in the superior mechanical properties of isotactic-poly(1-butene) elucidated by solid-state NMR

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