浸渍过程对纳米纤维素/二氧化硅复合气凝胶结构与性能研究  

Effect of Immersion Process on the Properties and Structure of Cellulose Nanofibril/Silica Composite Aerogels

作　　者：付菁菁[1,2] 何春霞[1,2] 王思群 FU Jing-jing HE Chun-xia WANG Si-qun(College of Engineering Nanjing Agricultural University, Nangjing 210031, China Key Laboratory of Intelligence Agriculture Equipment of Jiangsu Province, Nanjing 210031, China Center for Renewable Carbon, University of Tennessee, Knoxville, TN 37996, USA)

机构地区：[1]南京农业大学工学院,江苏南京210031 [2]江苏省智能化农业装备重点实验室,江苏南京210031 [3]Center for Renewable Carbon,University of Tennessee

出　　处：《光谱学与光谱分析》2017年第7期2019-2023,共5页Spectroscopy and Spectral Analysis

基　　金：林业公益化行业科研专项(201504603);国家科技支撑计划项目(2011BAD20B202-2)资助

摘　　要：纳米纤维素(CNF)气凝胶兼具传统气凝胶的优异特性和自身优良的生物相容性和可降解性,在很多领域应用前景广阔。然而纤维素自身的超亲水性严重限制了其更广泛的应用,为改善纤维素气凝胶的亲水性能,提高其综合应用性能,采用简单浸渍法在纤维素气凝胶基体中引入二氧化硅(SiO_2)颗粒制备纳米纤维素/二氧化硅复合气凝胶,利用傅里叶红外光谱仪(FTIR)分析纤维素气凝胶和复合气凝胶的化学结构;用扫描电镜(SEM)观察气凝胶的微观结构;测定气凝胶的物理、力学性能和接触角。结果表明,复合气凝胶在3 340cm^(-1)处—OH吸收峰较纤维素气凝胶均有所减弱,表明SiO_2的引入促使Si—OH形成,也降低了气凝胶的亲水性,同时有Si—CH3和Si—O—Si吸收振动峰出现,表明三甲基氯硅烷(TMCS)的改性作用以及纤维素与SiO_2颗粒之间形成稳定化学键连接。浸渍时间影响硅含量,进而影响气凝胶的密度、比表面积和孔隙率。当浸渍时间为10min时制备的复合气凝胶性能较好,其微观结构分布均匀,具有疏水性能,接触角可达152°,同时气凝胶仍具有较好的力学性能和较低密度,其压缩模量和压缩性能分别为5.91和1.38MPa,密度为0.1g·cm^(-3)。Cellulose nanofibril（CNF）aerogels combine important properties of conventional silica aerogels with their own excellent biocompatibility and biodegradability,which could be applied in various fields.However,applications for cellulose aerogels have been limited by cellulose＇s hygroscopicity.In order to improve the hydrophilicity and comprehensive properties of cellulose aerogels,the simple immersion method was used to introduce silica parties into the cellulose matrix to synthesis cellulose nanofibril/silica composite aerogels.The chemical structure of cellulose aerogel and composite aerogels was analyzed with Fourier transform infrared spectroscopy（FTIR）.The microstructure of aerogels was observed by scanning electron microscope（SEM）.The physical,mechanical properties and contact angle of aerogels were tested and analyzed.The results show that the peaks of—OH located at 3 340cm-1 in composite aerogels were all weaker compared with cellulose aerogel,which indicates that the formation of Si-OH due to the introduction of silica and also lowered the hydrophilicity of cellulose aerogel.The appearance of the peaks of Si—CH3and Si—O—Si represents the modification of trimethylchlorosilane（TMCS）and the formation of stable chemical bond between cellulose and silica particles.The silica content of the composite aerogels was affected by the immersion time,and in turn affected the density,BET surface area and porosity of aerogels.The composite aerogel had better comprehensive properties when immersed into silica sol for 10 min.It had homogeneous microstructure and hydrophobicity,with contact angle of 152°.It also had good mechanical properties and low density,the compressive modulus and strength of the composite aerogel were 5.91 and 1.38 MPa,respectively.Its density was only 0.1g·cm-3.

关 键 词：纤维素气凝胶 二氧化硅 傅里叶变换红外光谱 微观结构 疏水改性 

分 类 号：O636.1[理学—高分子化学]