摘要
杉木存在结构疏松、材质轻软、强度低等缺陷,对其进行浸渍改性是提高其性能的重要方法,然而传统有机树脂浸渍改性存在释放有毒害气体、易燃等危害人居环境安全的严重问题。鉴于此,采用无机物质对杉木进行浸渍改性可显著提高杉木力学性能、尺寸稳定性、阻燃抑烟等性能,实现低值杉木的高值化利用。以硅酸钠为浸渍改性剂,硫酸盐、钙盐和磷酸盐复配物为固化剂,通过仿生呼吸法制得硅酸盐改性杉木。探讨了硅酸钠模数、硅酸钠质量分数、浸渍压力、浸渍时间、呼吸次数和呼吸频率(负压时间/正压时间)对改性杉木质量增加率和力学性能的影响,并采用扫描电子显微镜(SEM)和热重分析仪(TGA)对其微观形貌和耐热性能进行了表征。结果表明,当硅酸钠模数为3.4、硅酸钠浓度为30%、浸渍压力为0.5 MPa,浸渍时间为3 h、呼吸次数为6次、呼吸频率为2∶4时,改性杉木的质量增加率、抗弯强度、抗压强度和三切面硬度均为最佳。经过硅酸盐仿生改性后,改性杉木的横切面和纵切面都被硅酸盐较好填充,这也是杉木力学性能提高的原因。TGA分析表明,与杉木素材相比,改性杉木的耐热性能显著提高。
Abtract:Chinese fir has some major drawbacks,such as loose structure,light and soft,low strength,etc.Impregnation modification is an important method to improve its properties.However,the traditional organic resin impregnation modification had the serious problems of releasing toxic gas,inflammable,etc.In view of this,the mechanical properties,dimensional stability,fire resistance and smoke suppression of Chinese fir can be significantly improved by impregnation of inorganic materials,which can convert low grade Chinese fir into the high value wood products.The silicate modified Chinese fir was prepared by the bionic respiration method,in which,sodium silicates were used as the impregnating modifier,and the compound of sulfate,calcium salt and phosphate were as the curing agents.The effects of sodium silicate modulus,sodium silicate concentration,impregnation pressure,impregnation time,breathing times and respiration rate(negative pressure time/positive pressure time) on the weight percentage gain and mechanical properties of modified Chinese fir were studied.The micro morphology and heat resistance of the modified wood were characterized by the scanning electron microscopy(SEM) and thermogravimetry(TGA).The results showed that,when the sodium silicate modulus was 3.4,the sodium silicate concentration was 30%,the impregnation pressure was 0.5 MPa,the impregnation time was 3 h,the breaths time was 6 times,and the respiration rate was 2:4,the weight percentage gain,bending strength,compressive strength and three section hardness of the modified Chinese fir were the best.After the silicate biomimetic modification,the transverse section and longitudinal section of the modified Chinese fir were filled with silicates,which was also the reason for the improvement of the mechanical properties of Chinese fir.The TGA analysis showed that the heat resistance of the modified Chinese fir was significantly improved compared with that of unmodified Chinese fir.
作者
李萍
张源
左迎峰
吕建雄
王向军
吴义强
LI Ping;ZHANG Yuan;ZUO Yingfeng;LYU Jianxiong;WANG Xiangjun;WU Yiqiang(College of Materials Science and Engineering,Central South University of Forestry and Technology,Changsha 410004,China;Research Institute of Wood Industry,Chinese Academy of Forestry,Beijing 100091,China;Tianying(Guangdong)Wood Industry Technology Limited Company,Jiangmen 529700,Guangdong,China)
出处
《林业工程学报》
CSCD
北大核心
2020年第6期57-63,共7页
Journal of Forestry Engineering
基金
湖南省科技重大专项(2017NK1010)
湖湘青年英才计划(2019RS2040)
国家自然科学基金项目(31770606)
湖南省研究生科研创新项目(CX20190600)。
关键词
杉木
木材改性
硅酸盐
仿生呼吸法
物理力学性能
耐热性能
Chinese fir
wood modification
silicate
bionic respiration method
physical and mechanical properties
heat resistance
