Study On Properties Of Heat Treated Salix Psammophila And Populus Simonii Wood

In this thesis, salix psammophila and populus simonii were used to be test material, Steam was chosen as the heat transfer medium, the heat treatment temperature were160℃、170℃and180℃, the heat treatment time were1h、2h and3h,then samples were treated under the different heat treatment conditions. The effect of treatment temperature and time were investigated on dimensional stability, mechanical properties and so on. The major achievements of this study were summarized as follows:1. With the treatment temperature higher and the treatment time longer, MEE of salix psammophila and populus simonii treated wood were increased differently on the different heat treatment conditions. MEE maximum ratio of salix psammophila treated wood was47.77%(treatment temperature180℃, treatment timelh), MEE maximum ratio of populus simonii treated wood was53.35%(treatment temperature180℃, treatment time3h). Treatment temperature and time had significant effect on MEE of salix psammophila and populus simonii treated wood, the treatment time had significant effect on MEE of populus simonii treated wood, but the treatment time had not obvious effect on MEE of salix psammophila treated wood.2. With the treatment temperature higher and the treatment time longer, ASE of Salix psammophila and populus simonii treated wood were increased differently on the different heat treatment conditions.ASE maximum ratio of salix psammophila treated wood was43.79%(treatment temperature180℃, treatment time3h), ASE maximum ratio of populus simonii treated wood was59.39%(treatment temperature180℃, treatment time3h). Treatment temperature had significant effect on ASE of salix psammophila and populus simonii treated wood, but the treatment time had not obvious effect.3. When treatment temperature was160℃, MOE of salix psammophila and populus simonii treated wood were improved differently on the different heat treatment conditions. The maximum MOE of salix psammophila treated wood increased by39.90%, and The maximum MOE of populus simonii treated wood increased by19.13%.When the treatment temperature was higher than160℃, MOE of salix psammophila and populus simonii treated wood decreased gradually, wood mechanical strength decreased obviously. Treatment temperature had significant effect on MOE of salix psammophila and populus simonii treated wood, but the treatment time had not obvious effect. 4. With the treat temperature higher and the treat time longer, MOR of salix psammophila and populus simonii treated wood were decreased gradually on the different heat treatment conditions. Treatment temperature had significant effect on MOR of salix psammophila and populus simonii treated wood, and treatment time had significant effect on MOR of salix psammophila, but the treatment time had not obvious effect on MOR of populus simonii.5. With the treat temperature higher and the treat time longer, the content of the hemicelluloses and holocellulose of salix psammophila and populus simonii treated wood decreased differently on the different heat treatment conditions, The content of the a-cellulose and lignin of salix psammophila and populus simonii treated wood had not obvious change. Treatment temperature had significant effect on the content of the holocellulose of populus simonii treated wood, and treatment temperature and time had not effect on the content of the other of salix psammophila and populus simonii.6. With the treatment temperature higher and the treatment time longer, the relative crystallinity of salix psammophila and populus simonii treated wood were increased differently on the different heat treatment conditions. The relative crystallinity of salix psammophila increase to68.51%(treatment temperature180℃, treatment time1h), which is24.35%higher than untreated samples. And the relative crystallinity of populus simonii increase to68.51%(treatment temperature180℃, treatment time3h), which is24.35%higher than untreated samples. But treatment temperature and time have no effect on the relative crystallinity of salix psammophila and populus simonii treated wood.7. With the treatment temperature higher and the treatment time longer, the content of-OH and C=O of salix psammophila and populus simonii treated wood decreased differently on the different heat treatment conditions. But a-cellulose and lignin of wood had good thermal stability, the content of the hemicelluloses was less, and the content of the a-cellulose and the lignin had not significant variation.