改性巴基管水泥基复合材料的力学性能及表征

The Flexural Strengths and Characteristics of the Cement-based Composite Reinforced with Acid-treated Multi-walled Carbon Nanotubes

巴基管水泥基复合材料是一种新型功能材料。尝试先对多壁巴基管(MWCNTs)进行表面氧化修饰,然后用表面活性剂超声分散法及混合浇注法,制备了巴基管水泥基材料(MWCNTs/CC或AT-MWCNTs/CC)。采用三点弯曲法测试了MWCNTs/CC及AT-MWCNTs/CC的抗弯折强度;用FT-IR对MWCNTs,AT-MWCNTs,MWCNTs/CC及AT-MWCNTs/CC的表面基团进行了对比分析;用SEM观察了MWCNTs/CC及AT-MWCNTs/CC的显微结构。结果表明:力学性能优异的MWCNTs直接混合到水泥中不仅没有起到增强作用,还会降低MWCNTs/CC的抗折强度,而改性的AT-MWCNTs能使AT-MWCNTs/CC的抗折强度比空白试件Plain/C高23.1%,且离散度低;FT-IR图显示AT-MWCNTs表面带有许多MWCNTs所没有的含氧亲水基团,相应AT-MWCNTs/CC的特征吸收峰也丰富许多;SEM图显示MWCNTs于MWCNTs/CC中与松散的水化产物间结合弱,而AT-MWCNTs表面覆盖了许多的水化产物,与质地致密的水化产物间结合力强,整体粘结界面好。

Carbon nanotubes/cement composite is a novel functional material. Acid-oxidization is applied to modify the surface of multi-walled carbon nanotubes （MWCNTs）, and afterwards, the cement-based composites reinforced with MWCNTs or AT-MWCNTs （MWCNTs/CC,or AT-MWCNTs/ CC） are prepared with surfactant ultrasonic dispersion and subsequent mix-casting method. Their flexural strengths are acquired with three-point bending test method, the surface characteristics of MWCNTs,AT-MWCNTs,MWCNTs/CC and AT-MWCNTs/CC are compared and analyzed with FT-IR apparatus,and the microstructures of MWCNTs/CC and AT-MWCNTs/CC are observed by SEM. The results show that, the flexural strength of MWCNTs/CC is lower than that of the reference, but AT-MWCNTs with surface modification exhibits good reinforcement to the matrix, and the enhancement amplitude of the strength of AT-MWCNTs/CC with respect to that of the reference is up to 23.1% ,and the homogeneity is better. Many hydrophilic active groups are found on the surface of AT-MWCNTs, which is hardly found on the surface of MWCNTs, and the correspondent absorption peaks of AT- MWCNTs/CC are much richer. SEM micrographs show that most MWCNTs have only weak bonding with loose hydration product, while there is many hydration products encapsulating AT-MWCNTs, exhibiting strong bonding force and good interfacial bond between AT-MWCNTs and the dense hydration product.