聚乙烯亚胺改性介孔二氧化硅SBA-15微观结构的小角X射线散射及正电子湮没谱学研究  

Small angle X-ray scattering and positron annihilation spectroscopy of polyethyleneimine functionalized ordered mesoporous silica SBA-15 microstructure

作　　者：尹昊 宋通 彭雄刚 张鹏[1] 于润升[1] 陈喆[2] 曹兴忠[1,4] 王宝义 Yin Hao;Song Tong;Peng Xiong-Gang;Zhang Peng;Yu Run-Sheng;Chen Zhe;Cao Xing-Zhong;Wang Bao-Yi(Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;School of Materials Science and Engineering,Wuhan Institute of Technology,Wuhan 430205,China;China Automotive Technology&Research Center Co.,Ltd.,Tianjin 300162,China;University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]中国科学院高能物理研究所,北京100049 [2]武汉工程大学材料科学与工程学院,武汉430205 [3]中国汽车技术研究中心有限公司,天津300162 [4]中国科学院大学,北京101408

出　　处：《物理学报》2023年第11期197-203,共7页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2019YFA0210002);国家自然科学基金(批准号:12275299,11875055)资助的课题.

摘　　要：SBA-15由于具有高比表面积、孔容大、孔径可调、热稳定性好和成本相对低廉等优点,在吸附、分离、催化和纳米材料等领域具有广泛的应用前景,而利用有机官能团改性SBA-15已经成为当前材料的热点之一,但有机官能团的引入势必会影响材料的孔结构,进而影响其性能.因此,如何更全面地表征材料的孔结构也成为人们关注的焦点.采用小角X射线散射(SAXS)技术对PEI/SBA-15介孔分子筛的孔结构进行表征,利用相关函数和弦长分布理论得到了聚乙烯亚胺改性介孔二氧化硅(PEI/SBA-15)的孔结构和周期性信息,结合正电子湮没寿命谱(PALS)技术进行比较.结果表明:随着PEI质量分数的增加,PEI/SBA-15介孔分子筛的周期性结构没有发生明显变化,通过弦长分布(CLD)函数得到的孔径尺寸也仅从8.3 nm降至7.6 nm.利用PALS获得了2种长寿命组分τ3和τ4,其中τ3反映了SBA-15基体内部的无规微孔结构,而τ4反映SBA-15六方孔道的尺寸,与SAXS结果相比,介孔孔径具有相同的变化趋势.通过结合SAXS和PALS技术,可以更加深入地揭示材料中微观结构的演变,从而为未来功能纳米复合材料的结构表征提供一种独特的方法.Owing to its advantages of high specific surface area,large pore volume,adjustable pore size,good thermal stability and relatively low cost,SBA-15 has a wide range of application prospects in adsorption,separation,catalysis,nanomaterials and other fields.And the use of organic functional groups to modify SBA-15 has become one of the hot spots of research on materials,but the introduction of organic functional groups will inevitably affect the pore structure of material,affecting its performance.Therefore,how to more comprehensively characterize the pore structure of material has received much attention.In this work,small angle X-ray scattering(SAXS)technique is used to characterize the pore structure of PEI/SBA-15 mesoporous molecular sieve.The pore structure and periodicity information of PEI/SBA-15 are obtained by using correlation function and string length distribution theory,and compared with those obtained by positron annihilation lifetime spectroscopy(PALS)technique.The results show that the periodic structure of PEI/SBA-15 mesoporous molecular sieve does not change significantly with the increase of PEI mass percent,and the pore size of PEI/SBA-15 mesoporous molecular sieve only decreases from 8.3 nm to 7.6 nm by the chord length distribution function.Two long-life components,τ3 andτ4,are obtained by PALS,andτ3 reflects the random pores structure in SBA-15 matrix,whileτ4 denotes the size of SBA-15 hexagonal pores.Compared with the results of SAXS,the mesoporous pore size obtained by PALS technique shows the same trend.By combining SAXS technique and PALS technique,the evolution of material microstructure can be revealed in more depth,thus providing a unique method for studying the structural characterization of functional nanocomposites in the future.

关 键 词：小角 X 射线散射 SBA-15 分子筛 正电子湮没寿命谱 

分 类 号：TB332[一般工业技术—材料科学与工程] O561[理学—原子与分子物理]