We present a small-angle X-ray scattering (SAXS) and
wide-angle
X-ray scattering (WAXS) characterization of the semicrystalline structure
of homo- and heterobicomponent core–sheath fibers melt-spun
from poly(ethylene terephthalate) (PET) and poly(phenylene sulfide)
(PPS). The two-dimensional SAXS/WAXS patterns of the various bicomponent
fibers are found to reflect the mutual influence of the components
on their thermal profiles along the spinline, leading to modified
crystallization of the PET component and a larger strain rate in the
PPS component. The predominant scattering features in the SAXS patterns
are four-point reflections, an intense equatorial streak, and a central
anisotropic diffuse scattering. The four-point reflections are attributed
to tilted crystalline lamellar stacks of PET. The lamellar stack dimensions
and the orientation of their lamellar surfaces are determined. We
find that the heterobicomponent arrangement can promote the formation
of equally spaced and uniformly sized crystallites in the PET phase
and highly oriented crystallites in the PPS phase.