CNTs@SiO_(2)核壳结构纳米线对水泥力学性能及微观结构的影响  

Effect of CNTs@SiO_(2)Core-Shell Nanowires on the Mechanical Properties andMicroscopic Structure of Cement

作　　者：朱建平[1] 张素娟 高飞 张文艳[1] ZHU Jianping;ZHANG Sujuan;GAO Fei;ZHANG Wenyan(School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China)

机构地区：[1]河南理工大学材料科学与工程学院,河南焦作454003

出　　处：《材料导报》2023年第16期125-130,共6页Materials Reports

基　　金：国家自然科学基金(51908198);绿色高性能建筑材料河南省杰出外籍科学家工作室(GZS2021003);河南省重大公益专项(201300311000)。

摘　　要：碳纳米管由于良好的力学性能被广泛应用于水泥基材料的增韧,但是碳纳米管与水泥基材料界面结合弱的问题亟需解决。本研究采用自组装的方法,对多壁碳纳米管表面进行包覆改性,合成二氧化硅包覆碳纳米管的核壳结构纳米线(CNTs@SiO_(2))。将原始碳纳米管(O-CNTs)、纯化碳纳米管(P-CNTs)以及CNTs@SiO_(2)掺入水泥中,研究碳纳米管对水泥材料力学性能的影响,并结合水化热、X射线衍射分析(XRD)、热分析(TG-DTG)、扫描电子显微镜分析(SEM)等测试方法,探究其对水泥基材料力学性能的影响机理。相比O-CNTs及P-CNTs,CNTs@SiO_(2)的掺入可显著提高水泥的早期力学性能,随着掺量的增加,抗折强度呈现先增加后降低的趋势;当CNTs@SiO_(2)的掺量为0.08%(质量分数,下同)时,对水泥的抗折强度改善效果最好,3 d抗折强度可提高18.8%。其原因是掺入CNTs@SiO_(2)提高了水泥水化反应速率,其表面的纳米SiO_(2)与硬化体中的氢氧化钙反应形成二次水化产物,提升了界面结合力,从而提高了水泥的力学性能。本研究为水泥基材料用碳纳米管的改性提供新的思路。Carbon nanotubes could be widely used to enhance the flexural toughness of cement-based materials due to the excellent mechanical properties.However,the weak interfacial adhesion between carbon nanotubes and cement-based materials is an urgent problem need to be solved.In this research,the surface of multi-walled carbon nanotubes was modified by self-assembly method,and the core-shell structure nanowires(CNTs@SiO_(2))of silicon dioxide coated carbon nanotubes were synthesized.The original carbon nanotubes(O-CNTs),purified carbon nanotubes(P-CNTs)and CNTs@SiO_(2)were incorporated into cement to investigate the influence of carbon nanotubes on the mechanical properties of cement-based materials.Hydration heat,X-ray diffraction analysis(XRD),thermal analysis(TG-DTG),scanning electron microscopy analysis(SEM)and other test methods were applied to explore the mechanism of their effect on the mechanical properties of cement-based materials.Compared with O-CNTs and P-CNTs,the incorporation of CNTs@SiO_(2)can significantly improve the early mechanical properties of cement,and with the increase of content of CNTs@SiO_(2),the flexural strength shows a tendency to increase first and then decrease;when the content of CNTs@SiO_(2)is 0.08%(mass fraction,the same below),the effect of improving the flexure strength of cement is the best,and the 3 d flexural strength can be increased by up to 18.8%.The reason is that the incorporation of CNTS@SiO_(2)promoted the hydration rate of cement,the nano-silica on the surface of CNTs@SiO_(2)could react with the calcium hydroxide in the hardened cement to form a second hydration product,which enhanced the interfacial adhesion.Therefore,the mechanical properties of cement are improved.The research provides a new idea for the modification of carbon nanotubes on the cement-based materials.

关 键 词：多壁碳纳米管 二氧化硅 表面包覆改性 力学性能 微观结构 

分 类 号：TQ172.1[化学工程—水泥工业]