六种木材的微波处理实验研究

Experimental Study of Six Species of Wood Treated by Microwave

微波处理可以破坏木材的微观结构,有效提高木材的流体渗透性。为探究微波处理木材流体渗透性改善机理,同时为人工林木材的功能化改性研究提供理论依据,文章对杉木、落叶松、樟子松、毛白杨、泡桐及尾巨桉六种木材进行微波处理实验。从扫描电镜图片中可以看出,微波处理后,微波处理材会产生射线薄壁细胞之间或与轴向组织的胞间层处产生破坏、闭塞纹孔的打开、纹孔膜破坏、细胞壁破坏及内含物重新分布等变化。微观结构的破坏导致处理材力学性能下降。其中,微波处理后樟子松、杉木、落叶松、尾巨桉、毛白杨及泡桐的抗弯弹性模量(MOE)较处理前分别下降了31.1%、35.4%、45.6%、5.5%、24.4%和23.2%;抗弯强度(MOR)分别下降了38.4%、29.4%、67.2%、9.1%、34.0%和29.1%。同时,不同树种木材中不同的微观结构破坏形式造成处理材不同的吸水性测试结果。而根据微波处理材的吸水性及力学性能测试结果,可以选择适合用于微波处理后进行功能化改性处理的树种。

Lumber microwave treatment results in structure changes of treated,it will enhance liquid permeability of treated lumber to make it easier for functional processing. In order to uncover the mechanism of permeability increase during microwave treatment,six species of wood were treated by high intensity microwave in present study.,Microstructure changes such as the separation of the ray parenchyma with axial tissue,unfolding of the aspirated pit,broken up in the wood cell wall,the distribution change of the tyloses in pores were found in Scanning Electron Microscopy( SEM) pictures taken before and after microwave treatment. These microstructure changes resulted in the mechanical properties decrease,in which the MOE decreased by 31. 1% 、35. 4% 、45. 6% 、5. 5% 、24. 4% and 23. 2% respectively for Chinese Fir( Cunninghamia lanceolata( Lamb.) Hook.),Siberian Larch( Larix gmelini( Rupr.) Rupr.),Mongolian Scotch Pine( Pinus Sylvestris L. var.),Chinese White Poplar( Populus tomentosa Carr.),South China Paulownia( Paulownia australis Gong Tong),( E. urophylla× E. grandis),while MOR decreased by 38. 4% 、29. 4% 、67. 2% 、9. 1% 、34. 0% and 29. 1%. Besides,different kinds of microstructure changes existed in different wood can also result in different water absorption rate changes for treated lumbers.According to the tests results,the species which are suitable for functional processing can be determined.