Solvent Quantification
A standardized testing procedure specifies the chemical method for determining the concentration of polyurethane in polyamide or polyester fiber blends by dissolution. Under this framework, the ISO 18260 extraction method relies on dimethylacetamide or dimethylformamide to selectively dissolve the elastane component without affecting the other fibers. This analysis is critical for confirming the fiber content declared on garments with stretch properties.
Laboratory Execution
Executing the test requires dried textile specimens to be agitated in the solvent at high temperatures for a specified duration. The residue is collected by filtration through a pre-weighed sintered glass crucible, washed with acetone, and dried to a constant weight. In the ISO 18260 extraction protocol, a specific correction factor must be applied to the residue weight to compensate for the slight solubility of the polyamide fiber in the hot solvent.
This mathematical correction prevents errors in the final composition calculation.
Polymer Separation
Selective separation of these polymer fibers is essential because even minor residue of the dissolved polymer on the fiber matrix can distort the results. To avoid this error, the washing step must be executed immediately using hot solvent to prevent the polymer from precipitating back onto the fibers.
Methodological Limit
Procedural boundaries restrict this analysis to blends that do not contain acrylic or modacrylic fibers because these synthetic polymers are also soluble in dimethylacetamide.
