In the previous paper, the relation between sulfidation and dissolution in emulsion xanthation of cellulose with varying amounts of carbon disulfide added at the constant alkali concentration (S-W curve) was examined, and it was found that S-W curve may be characterized by A
3 and (A
2/A
3-1) as a measure of reactivity of dissolving pulp, and (%-3) may be calculated from S-W curve as a measure of filterbility of viscose prepared by the conventional process. A
3 shows the average amount of dissolved per unit amount of carbon disulfide during the reaction, and (A
2/A
3-1) shows the non-uniformity of the S-W curve, and (%-3) is the amount of the dissolved during the last stage of reaction of emulsion xanthation (see Fig. 1).
In this paper, the effects of the degradation of pulp on the S-W curve were studied to make clear the relations between the S-W curve and the properties of pulp.
The results are as follows:
1) The shape of S-W curve is not effected by the lateral order or average degree of polymerization of cellulose alone.
2) When the pulp is degradated, the values of A
3 and (A
2/A
3-1) are varied in different ways according to the kind of pulp and methods of degradation. These values are influenced principally by the properties of the fraction which is dissolved in the last stage of reaction during emulsion xanthation (“hard soluble fraction”).
3) The “hard soluble fraction” of dissulving sulfite pulp is less effected by the acid hydrolysis in comparison with the fraction of dissolving sulfate pulp. Degradation with the irradiation to ultra violet ray as well as degradation with air aging of alkali cellulose scarecely effects on “hard soluble fraction”.
4) The fact that acid treatment increases the reactivity of pulp, found by T. Kleinert and others, may be explained by the increase of solubility of “hard soluble fraction” winh the acid hydrolysis.
5) The “hard soluble fraction” does not seem a particular, inherent part of pulp, but related to the morphological structure of fiber which is attacked by cooking and bleaching.
6) From the above, the follwing conclusion may be drawn, that is these characteristics of S-W curve, A
3and (A
2/A
3-l) are appropriate for measuring the reactivity of dissolving pulp.
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