WOOD RESEARCH Volume 62, Number 4, 2017
Lijie Qu, Jiali Zhang, Zhenyu Wang, Zhengbin He, and Songlin Yi

Effects of ultrasonic pretreatment on the drying characteristics of Eucalyptus grandis × Eucalyptus urophylla

In this paper, wood pretreatments were carried out at an ultrasound intensity of 300 W and a frequency of 40 kHz for 60 min, and the ensuing drying process used a temperature of 60 °C. The study analyzed the pretreated wood before and after ultrasonic pretreatment via drying dynamics, electron microscope scanning, and Fourier transform infrared spectroscopy. The results showed that ultrasonic pretreatment successfully improved the effective water diffusivity, decrease the drying time, reduce the amount of extractives on the inner wood pores, and create microchannels in the wood, resulting in improved heat and mass transfer rates. These results indicate that ultrasonic pretreatment is an effective method for the drying of eucalyptus.

WOOD RESEARCH Volume 64, Number 1, 2019
Jing Qian, Jinpeng Li, Zhenyu Wang, Lijie Qu, Yu Ding, Songlin Yi, and Zhengbin He

Effects of wax and dimethyl silicone oil mixed impregnation on dimensional stability of two hardwoods

In this experiment, cocobolo (Dalbergia retusa Hesml.) and African padauk (Pterocarpus soyauxii) specimen were selected before treating with wax, wax + 20% dimethyl silicone oil, wax + 40% dimethyl silicone oil at 120°C for 3 h and 6 h respectively. The weight gain percentage (WPG), radial swelling coefficients (RS), tangential swelling coefficients (TS), chemical composition and strength of hydroxyl groups were investigated. The results indicated that three factors affect dimensional stability, including the impregnation time, tree species and ratio of wax /dimethyl silicone oil. The degree of a melioration in the dimensional stability increase as the impregnation time increase from 3h to 6h. The effect of the impregnation on the dimensional stability of the African padauk was better than that of the cocobolo. Wax+ 40% dimethylsilicone oil was the optimal condition in this study. Wax and dimethylsilicone oil mixed impregnation can improve the dimensional stability to a certain extent, which provides a new idea for the wood modification.