Viscosity Measurement
Pulp samples undergo a controlled dissolution process to determine the chain length of cellulose molecules through iso 5351. This standardized procedure evaluates the fluid resistance of dissolved fibres by measuring the time a specific volume takes to pass through a capillary tube of known dimensions. Such results quantify the degree of polymerization that remains after the chemical pulping process, which provides the necessary data for assessing fibre strength before mechanical processing begins.
A reduction in flow time indicates shorter cellulose chains, while longer flow times confirm superior fibre structural integrity suitable for high-durability linen products.
Processing Impact
The laboratory environment maintains precise temperature controls to avoid thermal degradation of the dissolved samples. Precise calibration of the copper ethylenediamine solvent ensures that the solvent maintains the required chemical capacity for full dissolution without interference from atmospheric oxygen. Small deviations in solvent concentration alter the resulting viscosity readings, which necessitates frequent verification against certified reference materials.
Variations in the resulting viscosity values dictate the suitability of specific pulp lots for different spinning techniques in Chinese spinning mills.
Commercial Valuation
Contractual agreements often define a minimum viscosity threshold to guarantee the tensile performance of the final yarn produced from the supplied flax pulp. Buyers reject shipments where the viscosity falls beneath the established limit, because weak fibres cause excessive breakage during high-speed spinning operations. Mill operators use these laboratory outputs to decide the blend ratios of different fibre lots to stabilize the mechanical properties of the finished output.
Fibre quality relies on maintaining consistent cellulose chain length throughout the chemical modification stages.
