Anomalous dyeing behaviour has been found when regular acrylic fibre treated in hydrochloric acid, in which the sulphonic acid group was present entirely in the acid form, was dyed in neutral condition with azo and anthraquinone disperse dyes. In the very early stages of dyeing there was an abnormally high degree of dye exhaustion, with bathochromic (azo) or hypsochromic (anthraquinone) colour changes on the fibre. These phenomena gradually disappeared after prolonged dyeing, with normal adsorption equilibria and colours eventually being obtained. The results were explained on the basis of protonation by the sulphonic acid groups of treated fibre which occurs at the azo nitrogen or the amino nitrogens of the substituents in the 1-or 1,4-positions of anthraquinone. The normal adsorption equilibria after prolonged dyeing was attributed to hydrolysis of the cyano side group to form carboxylic acid. This produces ammonia to liberate neutral dye from the protonated dye cation adsorbed electrostatically by the sulphonic acid anion of the treated fibre.

The effect of hemicellulose contents in pulp on beating rate and strength of paper made from it was studied.In this study two methods were used, one the adding method (adding isolated hemicellulose to the standard pulp) and the other the extracting method (removing hemicellulose stepwisely).In the former when the hemicellulose is isolated with drastic agents, chemical nature of hemicel lulose is liable to change, so that it is impossible to say that the isolated hemicellulose will act in the same manner as it does in the original state. Therefore extracting method was employed in the present research.For the preparation of chlorite holocellulose, thin pieces of beech and aspen wood were treated with hot acidified sodium chlorite. These chlorite holocelluloses were treated with KOH solution under nitrogen gas, in order to minimize the oxidation of cellulose. For hemicellulose extraction, KOH solutions of various concentration (from 0.3 to 20 %) were used in order to get a series of pulp in which the hemicellulose content was stepwisely arranged.The beating rate and the sheet strength of this series of pulp were examined. From the result of this study, it was concluded that there appeared to be the optimum hemicellulose content in pulp as for as the paper strength was concerned. Other observations were also made with regard to the result observed.(Received 18. 7. 1955) Fig. 1. Relation between the hemicellulose content and the beating rate (beech pulp). Fig. 2. Relation between the hemicellulose content and the beating rate (aspen pulp).

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