Polymer crystallization under flow
formation mechanism of fiber structure  
When polymers are crystallized under flows such as elongational and/or shear flows the so-called shish-kebab structure is formed, which consists of long central fiber core (shish) surrounded by lamellar crystalline structure (kebab) periodically attached along the shish.  It is believed that the shish is formed by crystallization of completely stretched polymer chains and the kebabs are folded chain lamella crystals and grow to the direction normal to the shish.  The shish-kebab structure is very important from industrial viewpoint because it is structural origin of ultra-high strength and ultra-high modulus fiber. However, the formation mechanism is not still clear. In this work we have the formation mechanism of shish-kebab structure using light scattering, SR small- and wide-angle X-ray scattering , and neutron scattering to cover a very wide spatial scale. 



Schematic illustration of shish-kebab structure




Polymer, 46, 1878 (2005)
Polymer, 47, 5669 (2006)
Macromolecules, 39, 7617 (2006)
Time evolution of shishi-kebab structure in a wie scale
Effect of high molecular weight component on shish formation

Critical concentration of HMWPE is =0.5 wt %
DPLS(upper)、SAXS(middle)、WAXS(lower)

Shish-kebab structure formation depends on shear rate and strain, showing relaxation plays an important role in the formation.
SANS and SAXS of d-PE including 2.8% h-UHMWPE, showing UHMWPE forms shish