TIT# Nanostructure Evolution of Homogeneous Poly(ethylene-co-1-octene) as
     a Function of Strain
AUT# Stribeck, Norbert; Androsch, René; Funari, Sérgio S.;
SOU# Macromol. Chem. Phys. (2003), 204(9), 1202-1216
LOC# xv079
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ABS# Polyolefine elastomers with varying 1-octene content
     and different thermal history are studied by
     wide--angle X-ray scattering (WAXS) and small--angle
     X-ray scattering (SAXS) during drawing and after
     relaxation. The multidimensional chord distribution
     function (CDF) reveals the nanostructure made from
     crystallites in the amorphous matrix. Both lamellae and
     granular crystals are found. Lamellae do not form
     stacks. The SAXS peak is observed because each lamella
     is covered by an amorphous layer of well--defined
     thickness. Arrangement, rotation, fine chain slip and
     failure of the domains are directly observed as a
     function of elongation. During straining and relaxation
     a well oriented macrolattice with colloidal dimensions
     but short--ranging order is formed. Two processes are
     generating microfibrils, namely (1) arrangement of
     granular crystallites, and (2) irreversible disruption
     of lamellae (coarse slip) followed by arrangement of
     their fragments. The second process stabilizes the
     colloidal lattice permanently. The higher the comonomer
     content, the later the irreversible process starts.
     Quenching from the melt shifts the onset to lower
     deformation. Deformation of microfibrils is not
     homogeneous. Instead, there is a limiting long period
     that cannot be exceeded without disruption. It is
     related to the position of the maximum in the SAXS
     pattern (which is almost constant).