BTCA交联纳米纤维素气凝胶的结构及性能  

Structure and Properties of BTCA Cross-Linked Cellulose Nanofibril Aerogels

作　　者：郭丽敏 陈志林[1] 吕少一[1] 王思群[2] Guo Limin1, Chen Zhilin1, Lu Shaoyi1, Wang Siqun2(1. Research Institute of Wood Industry, CAF Beijing 100091 ; 2. Center for Renewable Carbon, University of Tennessee Knoxville 3799)

机构地区：[1]中国林业科学研究院木材工业研究所,北京100091 [2]美国田纳西大学可再生碳中心,诺克斯维尔379964570

出　　处：《林业科学》2018年第4期113-120,共8页Scientia Silvae Sinicae

基　　金：中央级公益性科研院所基本科研业务费专项资金(CAFINT2014K02);林业公益性行业科研专项"纳米纤维素绿色制备和高值化应用技术研究"(201504603)

摘　　要：【目的】制备基于1,2,3,4-丁烷四羧酸(BTCA)的化学交联型纳米纤维素(CNF)气凝胶,研究交联程度对CNF气凝胶化学结构、微观形貌和物理力学性能的影响规律,为下一步功能型CNF气凝胶的开发奠定基础。【方法】配制不同质量比的CNF与BTCA混合水悬浮液,采用常规冷冻干燥和后交联方法制备出具有不同交联结构的CNF气凝胶,利用傅里叶变换红外光谱仪(FTIR)、X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)和全自动比表面积孔径分析仪对气凝胶的化学结构、微观形貌、比表面积和孔径分布进行表征分析,并测试其力学性能。【结果】1)与纯CNF气凝胶相比,BTCA交联型CNF气凝胶的FTIR和XPS谱图形态均发生明显变化,FTIR谱图中羟基(—OH)吸收峰减弱而羰基(C=O)吸收峰增强,XPS谱图中C1s的C1、C2、C3能谱均有较大幅度变化,并且拟合出C4(O—C=O)能谱。2)CNF气凝胶经BTCA交联后,其孔结构由原来的缝形孔变为相对规整的柱状孔。随着BTCA含量增加,其比表面积和总孔容逐渐减小,当m(CNF)/m(BTCA)为10/1时,CNF气凝胶的比表面积和总孔容分别从原来的62.8 m^2·g^(-1)、0.21 cm^3·g^(-1)减小到35.5 m^2·g^(-1)、0.098 m^2·g^(-1),降低了将近一半;当m(CNF)/m(BTCA)达到10/4时,CNF气凝胶的整体结构变疏松、易掉渣,出现明显酯化现象。3)纯CNF气凝胶的密度仅5.76 mg·cm^(-3),在100 g载荷下的压缩率高达62.4%,压缩回弹率仅30%。随着BTCA含量增加,其密度和压缩回弹率逐渐增大,压缩率则逐渐减小,当m(CNF)/m(BTCA)为10/1时,CNF气凝胶仍表现出较低的密度(7.67 mg·cm^(-3)),压缩率略微下降(56.8%),但压缩回弹率显著增加(80.8%);当m(CNF)/m(BTCA)达到10/4时,CNF气凝胶的密度增加到9.54 mg·cm^(-3),其压缩率(下降到34%)和回弹率(增加到95%)均发生了显著变化。【结论】BTCA使CNF气凝胶形成化学键结合的交联结构,对其孔隙结构和物理力学性能产生明显影响。BTCA�【Objective】1,2,3,4-butanetetracar boxylic acid（ BTCA） cross-linked cellulose nanofibril（ CNF） aerogels were used to study the effects of cross-linking degree on the chemical characterization,morphological,and mechanical property of the CNF aerogels,which laid the foundation for further development of functional CNF aerogels.【Method】 In this paper,we prepared the cross-linked CNF aerogels with different cross-linking degrees by adjusting the addition ratio of raw materials via freeze drying and post cross-linking method. The chemical characterization,morphological,surface area,pore size distribution,and mechanical property of the CNF aerogels were analyzed by means of Fourier transform infrared spectroscopy（ FTIR）,X-ray photoelectron spectroscopy（ XPS）,Scanning electron microscopy（ SEM）,BET measurement and mechanical tests.【Result】 Results showed that： 1） Compared with those of the pure CNF aerogel,the FTIR and XPS spectra of the BTCA cross-linked CNF aerogel were changed obviously,the absorption peak intensity of hydroxyl（ —OH）was observed weaker and that of carbonyl absorption peak（ C=O） was enhanced significantly. The C1,C2 and C3 spectra of C1 s in the XPS spectrum were all greatly changed,and the C4（ O—C=O） energy spectrum was fitted. 2） The porestructure of the cross-linked CNF aerogels changed from the original irregularly shaped pores to relatively regular columnar pores. With the increase of BTCA content,the specific surface area and total pore volume gradually decreased. When the m（ CNF）/m（ BTCA） was 10/1,the specific surface area and total pore volume of CNF aerogels were reduced from62. 8 m^2·g^-1 and 0. 21 cm^3·g^-1 to 35. 5 m^2·g^-1 and 0. 098 cm^3·g^-1,respectively,reduced by nearly half. When the m（ CNF）/m（ BTCA） reached 10/4,the structure of the aerogel became loose and appeared the excessive esterification phenomenon. 3） The density of pure CNF aerogels was only 5. 76 mg·cm^-3,and its compression rate was up to 62. 4%und

关 键 词：纳米纤维素 气凝胶 1 2 3 4-丁烷四羧酸(BTCA) 化学交联 

分 类 号：S785[农业科学—林学]