Correlating Monomer Ratio Variances in Flax Middle Lamella Lignin to Drafting Force Instability
Low S/G monomer ratios in flax middle lamella increase lignin cross-linking, elevating wet drafting force variability and driving yarn count instability.
Thermal Plasticization
Polymer Softening
Softening transitions of amorphous structural polymers upon heating represent a fundamental physical change in organic materials. In linen processing, thermal plasticization of lignin and hemicellulose occurs when the flax fibres are exposed to hot water during the wet spinning process. This heating lowers the viscosity of the non-cellulosic binding agents, allowing the individual technical fibres to slide past each other more easily.
The transition permits the extraction of finer yarns than would be possible at room temperature.
Spinning Facilitation
Softened binding polymers are necessary for achieving high drafting ratios without breaking the continuous fibre strand. This thermal plasticization enables the rollers to draw the fibre bundles out into a thin, cohesive structure before twisting. When the water temperature is maintained at sixty degrees Celsius, the lignin achieves the optimal state of plasticity for processing.
This thermal control ensures that the spun yarn has high uniformity and a low defect rate.
Cooling Recovery
Immediate cooling of the drawn strand after twisting restores the rigidity of the lignin matrix, thereby locking the fibres into their new configuration. If the yarn is not cooled quickly, the polymers remain soft, which can lead to structural deformation and yarn breakages during the winding phase. The stability of the wound package thus relies on this rapid temperature reduction.