Study On Characterization Of Wood Preservation Drying And Integrated Treatment

Proper preservation and drying for the wood is one of the effective paths to prolong the useful life period of the wood, improve the service performance of the wood, reduce the consumption of the wood, protect the ecological environment and utilize properly the wood and save the wood. It is increasingly evident that the conflict confronted by us is that the wood is in shortly supply relative to the demand required by the market at a serious shortage of forest resources in China. Therefore it is important to optimize the preservative-treated and drying process of the wood, research the environmental protection, high efficiency, energy-saving of the integrated technique for pressure and vacuum preservative-treated and drying of the wood. It is great significance to improve the quality of the preservative-treated and drying process wood and production efficiency, reduce energy consumption and save the wood efficiently.The thesis is closely focusing on resolving the practical problem of the production period too long, environmental pollution severity and the quality of the preservative-treated and drying process wood difficult to ensure. It is mainly to analyze the influence factors of the vacuum-pressure preservative-treated process; optimize the preservative-treated and drying process of the wood; to research the drying technical of preservative-treated wood; to analyses microscopic constitution of the preservative-treated wood; test and analyses mechanical property, glue bond property, surface painting property and provide a theoretical basis for determining the proper integrated technique of preservative-treated and drying of the wood. The results are as follows:(1) In order to obtain the reasonable vacuum-pressure the preservative-treated process of wood, this paper analyzes the influence factors of the wood preservative-treated process with the method of orthogonal experimental design. Preservative concentration is the main factors to influence the wood preservative retention of Pinus massoniana Lamb and Populus tomentosa Carr. It reached extremely significant level; pressure is the secondary main factors to influence the wood preservative retention of Pinus massoniana Lamb and Populus tomentosa Carr. It reached significant level; Pressure duration pre-vacuum duration are no significant to influence the wood preservative retention of Pinus massoniana Lamb. Pre-vacuum duration is few significant to influence the wood preservative retention of Populus tomentosa Carr. Pressure duration is no significant to influence the wood preservative retention of Populus tomentosa Carr.(2)The reasonable vacuum-pressure the preservative-treated process of wood is obtained with the method of orthogonal experimental design and the variance analysis. It shows that 1.2 percent preservative concentration, 1.2MPa pressure, 1h pressure duration,30minutes pre-vacuum duration are the optimization preservative-treated process of the Pinus massoniana Lamb and that 1.2 percent preservative concentration, 1.5MPa pressure, 2h pressure duration, 45minutes pre-vacuum duration are the optimization preservative-treated process of the Populus tomentosa Can.(3) Laboratory test for toxicity of wood preservatives to decay fungi with Pinus massoniana Lamb and Populus tomentosa Carr. The result shows that the weight loss percentage of wood is less than 10% with vacuum-pressure process and ACQ-D preservatives and reaches the strong durability gradation.(4) Drying temperatures is strongly influence the preservatives leaching rate of the preservative-treated. The percentage of preservatives leached from the preservative-treated Pinus massoniana Lamb increased as the drying temperatures higher. Integration production efficiency and the preservatives leaching rate influenced by the drying temperatures, the proper drying temperatures of preservative-treated Pinus massoniana Lamb is around 70℃. The percentage of preservatives leached from the preservative-treated Populus tomentosa Can increased as the drying temperatures higher.the percentage of the preservatives leached from the lumber was decreased small while the 20mm, 30mm preservative-treated Populus tomentosa Can were dried at the drying temperatures 75℃and the 40mm preservative-treated Populus tomentosa Can was dried at the drying temperatures 70℃with depression wet and dry bulb.(5) The MOE, MOR and the compressive strength parallel to grain of preservative-treated Pinus massoniana Lamb and Populus tomentosa Can wood were decreased with increasing the drying temperatures and the preservative retention.(6) The bond strength of preservative-treated Pinus massoniana Lamb and Populus tomentosa Can wood were improved with increasing drying temperatures. The bond strength of preservative-treated Pinus massoniana Lamb and Populus tomentosa Can wood were decreased with increasing preservative retention.(7) There is no negative impact on the surface painting property of preservative-treated and drying Pinus massoniana Lamb and Populus tomentosa Can wood.(8) The distribution of preservative in the three section of preservative-treated and drying wood was observed with the electronic microscope. For the preservative-treated and drying Pinus massoniana Lamb wood, in the transverse section, the preservative was found in the tracheid, resin canal and wood ray. In the tangential section, the preservative was found surrounding the resin canal. In the radial section, the preservative was found in the tracheid, wood ray, fenestriform cross-field pit and surrounding pit of the tracheid wall. The preservative in the spring wood is more than in the autumn wood. It was mainly found in the cross field of the wood ray and tracheid. For the preservative-treated and drying Populus tomentosa Can wood, in the transverse section, the preservative was found in the vessel. In the radial section, the preservative was found in the wood ray field that it has little filling material, and the surrounding of the vessel wall pit. In the tangential section, the preservative was mainly found near the vessel wall pit, vessel wall and vessel molecule.(9) The distribution of preservative in the preservative-treated and drying wood was observed with the electronic microscope., the preservative the preservative-treated and drying Pinus massoniana Lamb wood, was found surrounding pit of the tracheid wall. The preservative was mainly found near the vessel wall pit. Thus, the preservative-treated wood in the drying process, the lower drying temperatures can supply sufficient fixation time of the preservative; the higher drying temperatures easily lead to the preservative was not accreted effective and moved by the water, and accreted to the surface of the wood and leached quickly.(10) The transverse section SEM micrograph of preservative-treated and drying Pinus massoniana Lamb and Populus tomentosa Carr wood was observed. The transverse section cells of preservative-treated and drying wood were separated and distorted. The dehiscence degree of autumn wood changed less than the spring wood. The dehiscence degree of Pinus massoniana Lamb wood changed more than the Populus tomentosa Carr wood. The distortion and dehiscence among the cell walls of the preservative-treated wood are the main factors to influence the material strength decreasing.(11) The FTIR was analyzed between untreated and preservative-treated and drying Pinus massoniana Lamb and Populus tomentosa Carr wood with the different preservative-treated and drying process. The results indicated that the main absorb band of the preservative-treated wood with treated different preservative-treated and drying process has small influence. The preservative-treated and drying Pinus massoniana Lamb at 3408cm^-1 band and Populus tomentosa Carr wood at 3337cm^-1 band, the -OH expansion vibration absorption peak decreased it is concluded that complex reaction were generated between the -OH and the copper of preservative. The preservative-treated and drying Pinus massoniana Lamb at 1662cm^-1 band and Populus tomentosa Carr wood at 1667cm^-1 band, the absorption peak of conjugate C=O visibly decreased at band, it is concluded that complex reaction were generated between the conjugate C=O and the copper of preservative. The preservative-treated and drying Pinus massoniana Lamb at 1600cm^-1 band and Populus tomentosa Carr wood at 1603cm^-1 band, the absorption peak of benzene ring diminished after a sort, it is concluded that ACQ-D has little influence on the lignin of the preservative-treated Pinus massoniana Lamb wood and Populus tomentosa Carr. The rangeability in main field of the preservative-treated Pinus massoniana Lamb wood changed more than the Populus tomentosa Carr wood.(12) Preservation and drying for the wood were firstly treated and studied at the same time, while the organic connection of the two procedures can reduce the occurrence of wood drying flaw effectively and also can simplify the operation, and reduce the labor intensity. The quality of the preservation and drying for the wood can controlled by highly automation production and reduce the environmental pollution. Based on the preliminary examination and combined the integrated machine for pressure and vacuum wood modification and drying, the technique of optimization and automation production was obtained. The main mechanical strength of the wood integrated by the preservative-treated and drying were decreased small, the technique fit for the industrialization.