Study On Compression Of Fast-growing Poplar And Effect On Its Properties With New Additive

The fast-growing poplar treated by high temperature and pressure steam was made by compression. Through testing the physical and the mechanical properties of the specimens which were not compressed and the specimens which were compressed, the effects of all factors on MOE, MOR, TS, RS were studied. On the base of the analysis, a new sort of additive was used to compressed wood, the effect of additive upon the properties of the compressed wood was researched. The results from the experiment showed:It was feasible to manufacture compressed wood with fast-growing poplar by hot temperature and pressure steam pressing. Experiment showed that MOE and MOR of the compressed wood increased magnificently and the dimensional stability of compressed wood was much better than the one made by hot pressing. Through the orthogonal experiment, the best technological parameters of producing the compressed wood were drawn: compression ratio was 30%, temperature was 190°C, moisture content before compression was 45%.The dimensional stability of the compressed wood improved greatly when the compressed wood was made with additive impregnation. Experiment indicated that MOE and MOR decreased to a certain extent, TS and RS dropped dramatically. The dimensional stability improved to a great extent. Synthetically, the compressed wood with good properties could be made by new additive impregnation with the concentration of 9%.The infrared spectrum of specimens showed that cellulose, hemicellulose and lignin in wood cell chemically changed during hot-pressing with high temperature and pressure steam, which destroyed the hydrophile group. The moisture absorption of compressed wood decreased and the dimensional stability improved.The micro structure of specimens showed that cell had a large deformation after the poplar was compressed which reduced the inter-space such as cell cavity. But the cell wall had not been destroyed and it kept its integrality. Furthermore, new additive did fill the wood cell cavity. It reduced the dimensional transfiguration of compressed wood after compression and improved its dimensional stability.