Физика процесса получения древесины с прочностью стали

Abstract

This review summarizes the processes followed in sequence by modifying the samples of natural wood in ultrasound, constituents compactioning and pulsed magnetic field. It is shown that the processing of samples by ultrasound allows plasticizing one of the major component of wood - lignin as effective as when it is exposed to highly toxic ammonia, previously used for this purpose. When plasticizing lignin is transferred from the glass in a plastic condition allowing to perform three-dimensional compaction of sample without its destruction. Then the most probable processes of absorption of ultrasound by wood samples are analyzed. Three-dimensional compaction of plasticized samples with their subsequent three-dimensional processing can significantly increase the hardness of the modified material. After compaction relaxation processes occur in samples. Therefore, analysis of the optimal parameters of thermal influence is made allowing speeding up the completion of these processes and stabilizing the new mechanical characteristics. Further impacts on such samples of relatively weak pulsed magnetic fields allow getting the material, not inferior in terms of mechanical properties to metallic specimens. Analysis of the processes occurring in such action in the wood samples suggests the hypothesis of the origin of additional covalent bonds such as C-O-C between macromolecules of cellulose. Further, the review discusses the possibility of such bonds. It has been shown that an important feature during exposure of sample to magnetic field is co-directivity of magnetic force lines and wood fibers. Exactly at such orientation of the samples in the field the maximum effect is achieved. Then the causes of this feature of magnetic influence are analyzed and the main conclusions are made; and assumptions about the possible use are made.