摘要
在碱性条件下,木质素可部分替代苯酚与甲醛反应制备木质素基酚醛树脂,酚醛树脂经物理发泡,高温碳化工艺生成木质素基泡沫炭。为达到调控木质素基泡孔炭的泡孔结构,改善其孔径分布比例的目的,选用600℃碳化后的泡沫炭(CF-600℃)作为活化基体,利用化学试剂KOH对泡沫炭进行原位活化。研究结果表明:纯碱木质素可以部分取代苯酚,与甲醛发生缩合反应生成酚醛树脂;酚醛树脂基泡沫在450℃时有最大分解速率2.04%/min,炭收率为54.36%; 600℃碳化后的泡沫炭(CF-600℃)、900℃碳化后的泡沫炭(CF-900℃)与KOH原位活化后的泡沫炭(CF-KOH)呈玻璃网状结构,泡孔由50～300μm的泡孔及孔壁组成; 3种泡沫炭皆为无定型炭,非石墨化的炭质结构; KOH原位活化后的泡沫炭(CF-KOH)微孔比例下降,中孔比例上升,比表面积可达1 094.14 m^2/g;且3种泡沫炭的表观密度在0.10～0.15 g/cm^3之间,压缩强度最高可达0.35 MPa。
As one of natural multi-phenol polymers,lignin has chemical structure similar to polyphenols. In addition,phenol could be partially replaced by lignin under alkaline conditions,and might be reacted with formaldehyde to form the lignin-based phenolic resin. At the same time,the phenolic foam was obtained by physical foaming,which processed the lignin-based carbon foam at high carbonization temperatures. To adjust the cell structure of lignin-based carbon foam and improve its distribution ratio of pore size,the carbonized carbon foam produced at 600 ℃( CF-600 ℃)was selected as the activated matrix,and the chemical reagent KOH was applied to regulate the carbon foam. The results showed that phenol could be partially replaced by pure alkali lignin,and the phenolic resin was prepared from phenol with formaldehyde. The developed lignin based phenolic resin has good thermal stability. The maximum carbon residue could be 54.36% when the maximum decomposition rate was 2.04%/min at 450 ℃. Three types of carbon foams,i.e. CF-600 ℃ carbonized at 600 ℃,CF-900 ℃ carbonized at 900 ℃ and CF-KOH produced by the in situ regulation,were all in glass reticular structures with the sizes of bubble hole and wall pore between 50-300 μm. Compared with the carbon foam carbonized at 600 ℃( CF-600 ℃),the pore structure of the in situ regulation of carbon foam( CF-KOH) was mostly damaged,and the surface became rougher under high temperatures. The three types of carbon foams were mainly amorphous carbon,and their crystals were non-graphitized carbon structure. In the meantime,this study also found a small amount of sodium chloride crystal existed in carbonization of the carbon foam of CF-600 ℃. After activation,the in situ regulation of the carbon foam of CF-KOH was changed,which not only altered the ratio of micropores,but also increased the proportion of mesoporous,resulting in a specific surface area of1 094.14 m^2/g. Moreover,the apparent densities of carbon foams were between 0.10 and 0.15 g/cm^3,and the compression strength could reach up to 0.35 MPa.
作者
周方浪
杨静
杨海艳
邓佳
郑志锋
秦永剑
史正军
ZHOU Fanglang;YANG Jing;YANG Haiyan;DENG Jia;ZHENG Zhifeng;QIN Yongjian;SHI Zhengjun(Key Laboratory for Forest Resources Conservation and Use in the Southwest Mountains of China,Southwest Forestry University,Kunming 650224,China;University Key Laboratory of Biomass Chemical Refinery&Synthesis,Southwest Forestry University,Kunming 650224,China)
出处
《林业工程学报》
CSCD
北大核心
2019年第2期99-105,共7页
Journal of Forestry Engineering
基金
国家自然科学基金(31760195
31560195)
国家重点研发专项(2017YFD0601003)
广西林产化学与工程重点实验室资助项目(GXFC-08)
