Study On Veneer Compression Of Fast-Growing Wood Of Poplar

Poplar veneer compression is a new technology. Following plasticity theory of wood, three phases of intenerating, compressing, shaping were processed to improve physical and mechanical capability. This technology expands the using area of plantation-grown Poplar, and improves its worthiness. Four factors were considered in this test including steaming time, compressing temperature, pressure and shaping time. Single factors tests were taken to found out the effect of factors on recovery rate. Tests of Between-Subjects Effects were taken to found the best technique parameters. Physical and mechanical capabilities were compared between original veneer and treated veneer.The study showed that:1. It is feasible to produce compressed veneer by using Poplar. With compressing temperature improved, pressure expanded and shaping time lengthen, air-drying recovery rate dropped, wetting recovery rate dropped, boiling recovery rate dropped too. However, the recovery rates dropped first, and then risen with steaming time lengthen.2. In four factors, the effect of compressing time was the most significant, and then was the steaming time and pressure;the effect of compressing temperature was the least. The best technique parameter was got: 160℃ compressing temperature, 6 MPa pressure, 10 min compressing time, 20 min steaming time. By these techniques parameters, the recovery rate is only 4.735%.3. Physical and mechanical capabilities were compared between original veneer and treated veneer, the density and rigidity of compressing veneer was larger than that of original veneer.4. The microstructure of original veneer and treated veneer was observed. The result showed that, with veneer compressed, fiber and canal of it were compressed, and deformed. Cell well of Polar almost wasn't destroyed, but the cell interspaced was decreased, and the bore deformed too, and even wrecked.