Alkali resistance of pulp refers to the stability of pulp in an alkaline environment. The Kappa value is usually used to represent the alkali resistance of the pulp, and the higher the Kappa value, the stronger the alkali resistance of the pulp. The determination method of Kappa value is as follows:
Sample preparation: take an appropriate amount of pulp sample, add it to the acidic reagent and stir evenly.
Titration: Titrate the sample with sodium hydroxide (NaOH) solution until the color of the test solution turns light yellow. During the titration, methyl red indicator needs to be added.
Calculation: Calculate the Kappa value according to the volume of sodium hydroxide solution consumed by titration and the quality of the sample. The calculation formula of Kappa value is: Kappa value=(V1-V2)×N×0.1/M, where V1 represents the volume of titration solution, V2 represents the volume of titration solution in blank test, N represents the concentration of sodium hydroxide solution, and M represents the quality of the sample.
NBCHAO reminds you: the determination of Kappa value is based on the oxidation reaction of soluble lignin and other pigments in the sample, so the Kappa value may be affected by some factors, such as the type of pulp and the preparation method of the sample , acidity in the solution, etc. Therefore, in actual operation, it is necessary to strictly control the experimental conditions to ensure the accuracy and reliability of the experiment.
