| Timber anticorrosion treatment can improve the wood property, prolong the service life of wood. Chemical preservatives used in the wood preservative treatment may do harm to human and animals’health, pollute the environment. Therefore, research the application of environmental and no chemicals added charring technology (high temperature heat treatment technology) on wood preservation is helpful to improve the use value of lumber, and has great significance for research and develop environmentally friendly anticorrosive wood.This paper used Populus platyphylla var. glauca and Mongolian Seoteh Pine with oil charring treatment and vacuum charring treatment. The effect of charring treatment was considered by temperature and time. Analyzes the influence of wood corrosion performance, physical and mechanical properties, chemical composition, etc with nine different charring treatment process. Conclusions are following.(1) The material corrosion performance with vacuum charring treatment and oil charring treatment had been improved significantly. Vacuum charring treated poplar in220℃,4h,6h and pine in220℃,2h,4h,6h reached the strong corrosion grades. Oil heat treatment with220℃,4h,6h made the weightlessness rate of poplar and pine less than10%and reached the strong corrosion level. So vacuum charring treatment was better than oil charring treatment in improving the wood corrosion resistance performance. According to the analysis of variance, the effects of temperature and time on the poplar and pine weightlessness rate were all significant.(2) The balance moisture contents, water absorptions and wet volume expansion rates of charring-treated poplar and pine were significantly reduced. Namely, the wood performance of moisture absorption and wet expansion were reduced and the wood dimensional stability was remarkablely improved. The balance moisture content of oil charring-treated wood was lower than vacuum charring-treated wood’s. The water absorbency of oil charring-treated wood was far worse than vacuum charring-treated wood. The wet volume expansion rates of two charring treatments had about the same decrease.(3) As the temperature and time of vacuum charring treatment and oil charring treatment increasing, MOR of poplar kept decreasing, and the biggest strength loss rates were44.03%,50.59%. MOE was first increased then reduced; vacuum charring-treated poplar MOE had a little change, but the differences of oil charring-treated poplar MOE in different temperatures were great. MOR of two carbonized pine were in a downward trend, maximum strength loss rates were19.41%(vacuum charring treatment),29.9%(oil charring treatment). MOE of charring-treated pine was higher than the untreated pine’; MOE of vacuum charring-treated pine first rised and then reduced, and MOE of oil charring-treated pine kept decreasing. MOR and MOE loss rates of oil charring-treated wood were greater than the vacuum charring treated wood’, so the harm of oil charring treatment to wood is greater.(4) Cellulose and alpha cellulose content of vacuum and oil charring-treated wood decreased with the increasing temperature, and the lignin content increased.(5) On the basis of infrared spectrum analysis, O-H absorption peak intensity at3411cm-1decreased obviously and free hydroxyl numbers significantly reduced, making the moisture content and hydroscopicity decreased. The absorption peaks at2914,1735,1424,1735cm-1all had different degrees of weakening, and it showed that charring treatment made the cellulose and hemicellulose of pine and poplar do pyrolytic reaction, while lignin basically had no degradation.(6) According to the performances of carbonized wood, the best carbonization process of vacuum charring-treated poplar is220℃,2h, and the best process of oil charring-treated poplar is220℃,2h. the best carbonization process of vacuum charring-treated pine is200℃,6h, and the best process of oil charring-treated pine is220℃,2h. |
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