作者机构：
[Zhang, Jijuan; Xue, Li; Zhang, Zhongfeng; Chen, Yang; Gui, Zhaozhen] Cent South Univ Forestry & Technol, Coll Furniture & Art Design, Changsha 410004, Peoples R China.;[Song, Feifei; Zhang, Jijuan; Zhang, Zhongfeng] Green Furniture Engn Technol Res Ctr, Natl Forestry & Grassland Adm, Changsha 410004, Peoples R China.
通讯机构：
[Zhongfeng Zhang] C;College of Furniture and Art Design, Central South University of Forestry and Technology, Changsha 410004, China<&wdkj&>Green Furniture Engineering Technology Research Center, National Forestry and Grassland Administration, Changsha 410004, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
To enhance mechanical properties and improve flame retardancy and smoke suppression of fast-growing poplar wood in wood applications, the wood was impregnated and modified. An organic phenolic prepolymer and inorganic sodium silicate was used as contrasting impregnation modifiers and wood samples were impregnated by a bionic "respiration" method with alternating positive and negative pressure. The weight percentage gain, density increase ratio, mechanical properties (bending and compressive strength and hardness), and water absorption rate of inorganic and organic-impregnated modified poplar wood (IIMPW and OIMPW, respectively) were compared and these properties in IIMPW were found to be higher than those of OIMPW with the exception of the water absorption rate which was lower than the OIMPW. This was attributed to the superior absorption of sodium silicate that also improved the impregnation, reinforcement, and dimensional stability in the IIMPW. The chemical structure, crystalline structure, internal morphology, flame retardancy, smoke suppression, and thermal stability of IIMPW and OIMPW were characterized by FT-IR, XRD, SEM, CONE, and TGA. FT-IR and XRD results showed that, although IIMPW cellulose crystallinity reduced the most, more chemical bonds were come into being in IIMPW, which explained the better physical and mechanical properties of IIMPW. Compared with OIMPW, IIMPW had better flame retardant and smoke suppression performance.
期刊：
Wood Science and Technology,2022年56(5):1487-1508 ISSN：0043-7719
通讯作者：
Ping Li<&wdkj&>Yingfeng Zuo
作者机构：
[Wu, Yiqiang; Yuan, Guangming; Zuo, Yingfeng; Zhang, Yuan; Bi, Xiaoqian] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.;[Li, Ping] Cent South Univ Forestry & Technol, Coll Furniture & Art Design, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Ping Li; Yingfeng Zuo] C;College of Furniture and Art Design, Central South University of Forestry and Technology, Changsha, People’s Republic of China<&wdkj&>College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, People’s Republic of China
摘要：
The mechanical and flame-retardant properties of sodium silicate-impregnated fast-growing poplar have been greatly improved by a wide variety of methods, which has solved the problem of insufficient supply of natural wood to a certain extent. However, sodium silicate is easily leached and has high hygroscopicity, and sodium silicate-modified poplar (SSMP) has low anti-shrink efficiency (ASE), which make it difficult to maintain its dimensional stability. Dimethylol dihydroxyethylene urea (DMDHEU) contains polyhydroxymethyl active groups that are highly reactive with wood fibers and sodium silicate. Therefore, in this study, sodium silicate and DMDHEU were used as a composite modifier to carry out vacuum-pressure-impregnation modification on fast-growing poplar to form a bridging structure. This treatment fixed the sodium silicate and improved the dimensional stability of poplar. Mechanical properties of poplar wood were improved by modifications with sodium silicate and DMDHEU. The dimensional stability was greatly improved, and the fixation of sodium silicate was improved. Compared with the SSMP, the leaching rate and ASE of SS/DDMP were reduced by 48.82% and 41.79%, respectively. XRD, FTIR, and XPS results showed that C–O–C and Si–O–C bonds were formed between DMDHEU and the wood cell walls and sodium silicate. These bonds closely bound the cellulose crystals, which reduced the number of –OH groups being accessible for water and, thus, the moisture absorption of SS/DDMP. In addition, due to the increase in crystallinity, the heat resistance was further enhanced. The cone calorimetry results showed that SS/DDMP had the lowest heat release rate and total heat release. Compared with SSMP, the mean smoke release rate (mean SPR) and total smoke release decreased by 40.38% and 40.83%, respectively. Moreover, the release of CO and CO2 decreased. In conclusion, compared with other modification methods, the use of SS/DD impregnation to modify poplar has the potential to produce good overall performance of poplar with high-dimensional stability, flame retardancy, and smoke suppression.
