Alkali Solubility

Test Procedure

Technicians immerse a weighed specimen of dry fibre into a ten percent sodium hydroxide solution for a fixed duration at a set temperature. The protocol requires consistent stirring to ensure the entire mass contacts the reagent evenly. After the reaction completes, a filtration step separates the undissolved solid remains from the liquid phase.

Workers then wash and dry the remaining fibre mass until a constant weight appears on the scale. Comparing this final weight against the initial dry specimen reveals the percentage of matter lost to the solvent.

Material Interpretation

Damage from over-bleaching or acid hydrolysis creates low molecular weight fragments that dissolve readily. High values indicate significant fibre degradation, which negatively impacts the tensile strength and performance of finished garments. Lower results confirm that the cellulose retains its structure and resists chemical breakdown.

Mill quality departments monitor these levels to prevent manufacturing defects that weaken the final thread.

Technical Boundary

Lab analysis of this metric applies exclusively to cellulosic materials like cotton or linen. Synthetic fibres do not respond to this reagent in the same manner, so the test provides no useful data for polyester or nylon blends. Presence of synthetic resins or crosslinking agents can mask the actual degradation level by preventing the solvent from reaching the fibre.

Accurate results depend upon the complete removal of all surface finishes before the test commences.