Quantitative Method
Standardized chemical and microscopic test methods determine the mass percentage of individual fibre components in blended textile products. In commercial linen testing, ISO 1833 fiber analysis specifies chemical dissolution and manual separation techniques to isolate flax from cotton, viscose or synthetic fibres in woven and knitted goods. The standard governs fabric composition labelling and import tariff compliance, terminating at the analytical threshold where chemically modified bast fibres cannot be distinguished from natural cellulose.
Dissolution Procedure
Testing laboratories prepare dry fabric specimens by removing non-fibrous materials like sizing compounds, oils and finishing resins through solvent extraction. The procedure applies selective chemical reagents to dissolve specific fibre types while leaving the remaining fibres intact. For instance, zinc chloride or sulfuric acid solutions dissolve viscose or cotton components without degrading the structural flax residue when temperature and exposure time are strictly controlled.
Technicians wash, dry and weigh the undissolved flax residue to calculate mass percentages corrected for official moisture regain values. Microscopic cross-section analysis supplements chemical dissolution when testing blends containing visually similar natural cellulosic fibres.
Method Limit
Laboratory protocols enforce precise temperature controls during chemical exposure to prevent non-target fibre degradation. Reagent concentration errors invalidate mass fraction calculations for multi-component yarns.
