摘要
【目的】为有效提升人工林杉木物理力学性能,以无机硅酸钠(Na_(2)SiO_(3))溶液为浸渍改性剂,硫酸镁(MgSO_(4))溶液为固化剂,采用真空–加压循环浸渍方法制备硅镁凝胶改性杉木,探究硫酸镁的添加量和不同浸渍工艺对改性杉木浸渍效果和性能的影响,并优化浸渍工艺为硅镁凝胶改性杉木的规模生产提供理论依据。【方法】通过单因素试验探讨硫酸镁和硅酸钠的摩尔比、浸渍时间、浸渍压力与负/正压时间比4个因素对杉木试件改性效果的影响,在此基础上设计L_(9)(3^(4))正交试验优化浸渍工艺参数。由最佳工艺制得硅镁凝胶改性杉木与硅酸钠改性杉木,考察其质量增加率、顺纹抗压强度、硬度、吸水率、抗流失率、耐热性等性能和微观形貌表征,对比两种改性杉木之间及与未处理杉木的差异。【结果】综合单因素和正交试验结果得到:以硫酸镁和硅酸钠的摩尔比为1∶2的MgSO_(4)溶液和Na_(2)SiO_(3)溶液改性杉木,浸渍时间2 h、浸渍压力0.3 MPa和负/正压时间比2∶1的条件下制得的硅镁凝胶改性杉木性能最佳。对比未处理杉木,硅镁凝胶改性杉木的抗压强度、端面硬度、弦切面硬度和径切面硬度分别提升81.1%、73.1%、52.6%和37.2%,吸水率由129.3%降至73.3%。SEM结果显示硅镁凝胶改性杉木中硫酸镁成功浸入杉木管胞与硅酸钠反应并将其固化,导致其沉积物形貌不同,相比硅酸钠改性杉木其抗流失性提升了22.1%。TGA曲线中硅镁凝胶改性杉木的质量损失速率显著降低,由于无机组分的浸入,残余质量提升了27.09%。【结论】杉木经硅镁凝胶改性后,密度和强度增加,耐水性能改善,硬度、抗流失性及热稳定性显著提高,较硅酸钠改性杉木更具性能和应用方面的优势。
[Objective]Impregnation modification can effectively improve the physical-mechanical properties of Chinese fir plantation wood.Herein,the sodium silicate(Na_(2)SiO_(3))and magnesium sulfate(MgSO_(4))was selected as impregnation modifier and fixing agent,separately.A silica-magnesium gel modified Chinese fir wood was manufactured using a vacuum-pressure cyclic impregnation method.In detail,the impregnation process conditions including MgSO_(4) content were further explored,which provided a theoretical basis for large-scale production of the silica-magnesium gel modified Chinese fir wood.[Method]Through the single factor experiment,the effects of four factors,the molar ratio of magnesium sulfate to sodium silicate(n(Mg)∶n(Si)),impregnation time,impregnation pressure and the ratio of positive and negative pressure time,on the modification effect of Chinese fir wood were investigated.The L_(9)(3^(4))orthogonal experiment was designed based on these single factor experiments to optimize the impregnation parameters.Properties such as mass increasing rate,compressive strength along grain,hardness,water absorption rate,leach resistance,thermal stability and micro-morphology characteristics of the material were investigated.Moreover,the silica-magnesium gel modified Chinese fir wood prepared by the optimal technical condition was compared with the sodium silicate modified Chinese fir wood and the untreated Chinese fir wood.[Result]According to the orthogonal and single-factor tests,the optimal process parameters for the silica-magnesium gel modified Chinese fir wood were followings:the MgSO_(4) solution and Na_(2)SiO_(3) solution with n(Mg)∶n(Si)of 1∶2,impregnation time of 2 h,impregnation positive pressure of 0.3 MPa and negative/positive pressure time ratio of 2∶1.Compared with untreated Chinese fir wood,the compressive strength,cross section hardness,tangential section hardness and radial section hardness of the silica-magnesium gel modified Chinese fir wood increased by 81.1%,73.1%,52.6%and 37.2%,respectively,and water absorption rate decreased from 129.3%to 73.3%.The results of scanning electron microscopy showed that the MgSO_(4) in the silica-magnesium gel modified Chinese fir wood was successfully immersed into the tracheid of Chinese fir wood and reacted with Na_(2)SiO_(3),resulting in different morphology deposits,with a leach resistance increased by 22.1%compared with that of sodium silicate modified Chinese fir wood.A decrease in the mass loss rate of silica-magnesium gel modified Chinese fir wood was observed,and the residual mass was increased by 27.09% due to the impregnation of the inorganic components.[Conclusion]The physical mechanical properties including density,mechanical strength,water resistance,hardness,leach resistance and thermal stability are significantly increased compared with regular fir wood.Compared with the sodium silicate modified Chinese fir wood,it has more performance and application advantages.
作者
王燕
张源
李萍
袁光明
李新功
王向军
左迎峰
Wang Yan;Zhang Yuan;Li Ping;Yuan Guangming;Li Xingong;Wang Xiangjun;Zuo Yingfeng(College of Materials Science and Engineering,Central South University of Forestry and Technology,Changsha 410004,Hunan,China;College of Furniture and Art Design,Central South University of Forestry and Technology,Changsha 410004,Hunan,China;Tianying(Guangdong)Wood Industry Technology Limited Company,Jiangmen 529700,Guangdong,China)
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2022年第8期125-133,共9页
Journal of Beijing Forestry University
基金
国家自然科学基金项目(32171708)
湖南省教育厅科学研究优秀青年项目(21B0238)
湖湘青年英才计划(2019RS2040)
湖南省科技创新计划(2021RC4062)。
关键词
人工林杉木
硅镁凝胶
浸渍工艺优化
抗压强度
抗流失性
Chinese fir plantation wood
silicon magnesium gel
optimization of impregnation process
compressive strength
leach resistance
