Butterfly patterns in crystalline polymers under uniaxial stretch.
We investigate the density fluctuations in crystalline polymers under uniaxial stretch in the order of submicrons to microns with two-dimensional ultrasmall-angle x-ray scattering. Before uniaxial stretch, we found isotropic density fluctuations obeying the mass fractal with the fractal dimension 2.6. After uniaxial stretch, the isotropic scattering pattern was transformed into the butterfly pattern. The butterfly pattern is caused by the stress-induced density fluctuations and the heterogeneous deformation associating with the spatial heterogeneity of stress field due to the distribution of crystalline and amorphous regions.
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
Mikihito
M
Takenaka
Hirofumi
H
Shimizu
Shotaro
S
Nishitsuji