The Relation Between Hemicellulose Contents in Pulp and Its Paper Strength

Abstract

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).

Kraft Cooking and Bleaching Ability of Lowdensity Acacia Wood and Hardwoods with Varying Chemical Characteristics of Lignin

“…The bleached pulp sheets obtained by using a high mixture ratio of Acacia hybrid wood lowered hemicellulose(xylan)content in this study. Therefore, in line with the previous study by Migita and others 13) , it is expected that paper properties such as breaking length, bursting strength, and folding endurance, except tearing strength, should decrease with decreasing xylan content. However, although sheet properties tended to decrease with increasing mixture ratio of Acacia hybrid wood, the ─ 121 ─ extent of decrease was small and did not affect the quality of paper products.…”