Study on the Improvement of the Permeability of <i>Eucalyptus grandis× Eucalyptus urophylla </i>by Microwave Radiation

Abstract

Low permeability of fast-growing eucalyptus wood restricts its high value in use. In order to explore effective ways of improving the permeability of eucalyptus wood, the method of applying microwave radiation to Eucalyptus urophylla (Eucalyptus grandis×Eucalyptus urophylla) is used to promote its rapid evaporation of water, by which vapor pressure highly increases inside, then vapor bubbles break through the weak points of the wood tissue, as a result, the permeability of the wood is improved. Under the same conditions, wood was tested to achieve the results of water absorption rate (WAR) and water loss rate (WLR) in water sorption measurement and saturated suction drying experiment respectively, after which the permeability, the modulus of rupture (MOR) as well as the modulus of elasticity (MOE) of the test wood are recorded. The results show that the WAR and WLR of the microwave treated wood is higher than that of the untreated wood. Thus it is concluded that microwave radiation can improve the permeability of urophylla wood. But the time of microwave pretreatment has a significant effect on the WAR and WLR, which may be associated with lower microwave power and the variability of the tested material. MOR and MOE of the test material did not change significantly after the microwave treatment.