Weight Basis
Absolute weight of a textile specimen after removing non-fibrous additives and moisture represents the pure polymer content. Calculating the clean dry fiber mass provides a base for determining commercial invoiced weight or fiber blend percentages. This value excludes oils, waxes, finishings and hygroscopic water.
Calculation Baseline
Verification occurs at the laboratory stage where bone dry weights are adjusted by standard moisture regain values. Commercial transactions rely on clean dry fiber mass to ensure payments cover actual polymer content rather than surface lubricants or atmospheric humidity.
Extraction Protocol
Scouring with petroleum ether or an aqueous solution removes spinning oils before the sample undergoes oven drying. The clean dry fiber mass emerges as the final weighing result after the specimen reaches constant weight at 105 degrees Celsius. Subsequent steps apply a specific percentage for regain to calculate the final commercial mass.
Analytical Limit
Chemical degradation of delicate fibers during scouring or overheating in the oven can introduce errors into the calculation. Natural impurities like vegetable matter in wool require additional manual or chemical removal to arrive at an accurate clean dry fiber mass. Results fluctuate if the scouring efficiency is low or if the drying time is insufficient to remove internal moisture.
Testing for this value is necessary when verifying claims about the pure fiber content of a delivery.
