Study On Compression Of Fast-Growing Wood Of Poplar

Through testing the physical and the mechanical properties of the specimens which aren't compressed and the specimens which are compressed after compressing the fast-growing wood of Populus nigra L.,,studying the effects of all factors on recovery rate, analyzing the infra red spectra and the micro structure of specimens, and groping the fixation mechanism of resilience of compression, we can draw the following results:1. It is feasible to produce compressed wood by utilize the Populus nigra L. Through the orthogonal experiment, we can draw the best technology parameters of producing compressed wood that are : moisture content before compressed is saturation which is about 160%, thickness after compressed is 2cm, compression ratio is 50%, hot press temperature is about 190℃, and the time of hot press is about 40min.2. Using the softener of CH during cooking the Populus nigra L, which can decrease the recovery ratio of compressed wood, the recovery ratio of thickness of compressed wood is only 2.1%, and the stability of size of compressed wood can be improved greatly. The permeability and the ability of extractable organic matter of CH are powerful, and CH do not damage the cell wall and harmless to the human, so it is meet the requirement of environmental protection.( the formaldehyde is not measured)3. The infra red spectra of specimens show that there are some changes of waves at the wavelength of 3400cm^-1 .which are attribute to the change of O-H in wood, at the wavelength of 2917 and 2850cm^-1 .which are attribute to the change of C-H in wood , at the wavelength of 1060cm^-1 .which are attribute to the change of C-O in wood, and at the wavelength of 1736cm^-1 , which are attribute to the change of C=O in wood. So it is clear that cellulose, hemicellulose and lignin in wood cell chemical] changes during soften and hot compress the Populus nigra L.4. The micro structure of compressed wood show that the cells, such as wooden fiber and pore, etc. are pushed, have a large deformation after the Populus nigra L be compressed. But the cell wall and the pore have not been destroyed. In the course of compressed, the fixation of compressed wood is mainly rely on the amount of hydraxyl decrease, crystallization and hot decomposition and crosslink reaction in cell wall's composition.