A Drying Technique for the Determination of the Bound Water in Pulp Fibers

Abstract

A drying method involving the use of a thermobalance was employed to determine the bound water in mechanical and chemical pulp fibers. The precision of this method is dependent on the uniformity of the test materials. The coefficient of variability of bound water determination on mechanical pulps ranged from 15 to 18% based on one in dividual sample. This variability decreased in chemical pulps, 10 to 12%, and about 2% in α-cellulose. For a precision superior to ±10% (95% confidence level) a minimum of 10 individual mechanical pulp samples have to be tested. Similary, seven and one tests have to be made on chemical pulps and α-cellulose, respectively. The method should be useful to the study of the drying behavior of homogenous materials such as low-yield pulps and cotton or other textile materials.