THE SWELLING OF PULP FIBERS DERIVED FROM THE ETHANOL-BASED ORGANOSOLVPROCESS

The ALCELL(R) process is an ethanol-based organosolv pulping process t hat is currently under development. The swelling of this novel solvent pulp fiber in ethanol-water mixtures was investigated experimentally as a function of ethanol concentration. The delta-value theory was the n applied to account for the experimental results. The centrifugation technique was used to determine the fiber swelling, expressed as milli liters per gram of moisture-free fibers. The experimental results show that the fiber swelling decreases continuously as the ethanol concent ration increases. The delta-value theory indicates that the swelling o f pulp fibers reaches a maximum when its delta-value is close to that of the solvent. Based on the atomic and functional group contributions of cellulose, the delta-value of pulp fibers was calculated to be 19. 3 (cal/cm(3))(0.5). The delta-value of the ethanol-water mixture decre ases from 22.41 to 12.08 (cal/cm(3))(0.5) when the ethanol concentrati on increases. It was concluded that the effect of the ethanol concentr ation on the swelling of the ALCELL fibers could be accounted for by t he delta-value theory.