Drying Urea Formaldehyde Resin-Modified Chinese Fir for Mining Supporting Materials

The drying characteristics of urea formaldehyde (UF) resin-impregnated Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) wood were determined by the 100 degrees C-test method and scanning electron and fluorescence microscopies to predict an optimal drying schedule. Compared with the untreated sample, the UF resin-impregnated Chinese fir wood presented a lower grade of initial checks and a faster initial drying velocity, but a higher grade of internal checks and a slower drying velocity at the later stage. The average drying velocity of the UF resin-impregnated wood was 38.9 percent lower than that of the untreated sample. The predicted drying schedule was applied to the UF resin-impregnated wood and the resulting grades of the drying characteristics were in good agreement with the required national standard values. The resulting dried UF resin-modified composite would become a potential candidate for a shallow depth rock mining supportive system with its stable mechanical performance.