Skin-Core Structure and Processing Effects
topic
Rapid surface quenching during melt spinning creates a skin layer (0.5–3 µm) with higher orientation and different crystallinity than the core. Skin is formed under high stress conditions; detected by etching cross-sections with NaOH and SEM imaging. Skin-core differences cause heterogeneous dye uptake (leading to ring dyeing), differential shrinkage, and surface mechanical properties distinct from bulk. More pronounced in thick monofilaments.
Role
Skin-core structural heterogeneity is a practical cause of quality problems (uneven dyeing, surface pilling, differential shrinkage) and an important concept for understanding the limitations of surface treatments and the basis of fibre cross-section engineering.