Abstract: The chemical composition and basic wood density of three fast-growing hardwoods(Populus euramericana, Eucalyptus grandis×E.urophylla and Acacia mangium) chips were analyzed. The pulping properties of three different hardwood pulps made by PRC-APMP technology were studied. The results showed that higher contents of polysaccharide and 1% NaOH extractive were identified in populus than those in eucalyptus and acacia. Eucalyptus had the highest lignin content, whereas the holocellulose content was lowest than that of populus and acacia. The basic density of eucalyptus was 0.45 g/cm³, which was larger than that of acacia(0.43 g/cm³) and populus (0.39 g/cm³). The PRC-APMP pulping process was carried out under the condition of impregnating with NaOH 5.5% and H₂O₂ of 5.0%. As a result, acacia showed the highest pulp yield, which was up to 83.8%, while the pulp yield of populus and eucalyptus were 82.4% and 81.3% respectively. A highest pulp brightness of 78.2%(ISO) was achieved for eucalyptus, while the brightnesses for populus and acacia were 75.3%(ISO) and 70.7%(ISO), respectively. Under the same beating degree, it was found that acacia pulps possessed the highest tensile strength index, but required more refining energy. Populus pulps showed higher tearing index than that of acacia and eucalyptus pulps, due to its longer fiber length. In contrast, eucalyptus pulps exhibited the highest apparent bulk the lowest tensile strength as well.

Key words: fast-growing hardwood, wood properties, chemi-mechanical pulping, PRC-APMP