Resolving High Speed Optical Fiber Fineness Discrepancies in Degummed Bast Fiber Blends
Resolving high-speed optical fiber fineness discrepancies in degummed bast fiber blends requires applying cross-sectional shape and pectin correction factors.
Fiber Lumen Collapse
Structural Change
Dehydration of the central cavity in flax cells during the drying phase causes a permanent flattening of the cell wall. This physical alteration, known as fiber lumen collapse, occurs when the liquid water within the lumen evaporates, creating high capillary tension that pulls the surrounding cellulose layers inward. The resulting cross-section changes from a hollow polygon to a flat, ribbon-like structure.
This alters the bending rigidity of the fibre.
Spinning Consequence
Winding tension and yarn density are altered by the altered shape of the dried cell walls. When fiber lumen collapse takes place, the loss of the central canal reduces the internal moisture capacity of the raw flax bundle. This makes the fibre less receptive to subsequent wetting during the wet spinning process, which is necessary to soften the pectins.
A stiffer fibre emerges from the drafting rollers.
Dyeing Behavior
Penetration of dyes and finishing agents depends on the surface area and porosity of the cell structure. Since fiber lumen collapse leaves less open volume inside the core, liquid dyes cannot settle evenly within the inner channel, meaning that color fastness and shade depth are governed almost entirely by external surface absorption. This can result in uneven color distribution if collapsed and non-collapsed fibres are mixed in the same batch.
Spinning mills must therefore control the drying temperature of the scutched flax carefully to prevent premature or uneven structural changes before the spinning process is complete, ensuring that the yarn accepts chemical treatments uniformly across the entire production lot.