Mechanism of the Modified Carbon Nanotubes Toughening DSP Cement Mortar

2015 ◽  
Vol 723 ◽  
pp. 406-409
Author(s):  
Jing Mei Tan ◽  
Ai Guo Wang ◽  
Wen Jun Su

The analysis is made for the modification of multi-walled carbon nanotubes and the mechanical properties and microstructure of the modified carbon nanotubes toughening DSP cement mortar, the existence and toughening effect of modified carbon nanotubes on the fracture surface of materials were analyzed. Results shows that, the surface of the carbon nanotubes in the sample is covered with cement hydration products, with the carbon nanotubes in drawing state on the fracture surface and both ends of the tube connected firmly with cement materials, thus carbon nanotubes improve the toughness of materials effectively.

2016 ◽  
Vol 70 (6) ◽  
Author(s):  
Agnieszka Piegat ◽  
Anna Jędrzejewska ◽  
Robert Peƚech ◽  
Iwona Peƚech

AbstractThe influence of the chemical modification of carbon nanotubes on the mechanical, thermal and electrical properties of poly(butylene terephthalate)-based composites was investigated. Polymer composites based on poly(butylene terephthalate) were obtained via in situ polymerisation or extrusion. Commercially available multi-walled carbon nanotubes (Nanocyl NC7000) at different loadings (mass %: 0.05, 0.25, 1, 2) were used as fillers. The functionalisation process took place under a chlorine atmosphere followed by a reaction with sodium hydroxide. The effect of carbon nanotube modification was analysed according to the changes in the polymer thermal and mechanical properties. An addition of modified carbon nanotubes in the amount of 0.05 mass % improved the mechanical properties of the composites in terms of both Young’s modulus and tensile strength by 5–10 % and 17–30 % compared with composites with unmodified carbon nanotubes and neat poly(butylene terephthalate), respectively. The in situ method of composite preparation was a more effective technique for enhancing the matrix–filler interactions, although a significantly lower amount of fillers were used than in the extrusion method.


2016 ◽  
Vol 711 ◽  
pp. 232-240 ◽  
Author(s):  
Ling Shi Meng ◽  
Christopher K.Y. Leung ◽  
Geng Ying Li

This paper studies the effects of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties and durability of polymer latex-modified cement mortar. Latex-modified cementitious materials possess many advantages. However, reduction of mechanical properties due to the introduction of an amorphous structure within the cement composite has limited its application. In this study, multi-walled carbon nanotubes functionalised with carboxyl group (MWCNTs-COOH), ranging from 0% to 0.15% by weight, are added into mortar modified with 0.6 wt.% polyvinyl alcohol (PVA) latex. Mechanical properties including compressive strength and flexural strength are measured. Water absorption test and rapid chloride diffusion test are performed to assess durability performance. Results indicate considerable increase of compressive strength and flexural strength, as well as improvement in durability, by the addition of MWCNTs-COOH. With Scanning Electron Microscopy conducted on both the latex solution and cement composite, the microstructural changes resulted from MWCNT addition are revealed.


2018 ◽  
Vol 276 ◽  
pp. 21-26
Author(s):  
Gintautas Skripkiūnas ◽  
Grigory Ivanovich Yakovlev ◽  
Ekaterina Karpova ◽  
Anastasiia Gordina ◽  
Arina Shaybadullina

There are many research devoted to the influence of carbon nanotubes (CNT) on the structure and properties of cement systems. In the course of this research, the combined influence of of multi-walled carbon nanotubes (MWCNT) and polycarboxylate (PCE) plasticizer on the products of hydration and the properties of hardened cement paste was investigated. The strength characteristics of nanomodified hardened cement paste and the hydration products were determined by the usage of modern methods of physico-mechanical and physico-chemical analyses. Based on the physico-chemical investigations, it was concluded the necessity of additional experiments, associated primary with questions of uniform distribution of the nanostructures and their chemical interactions with another components of admixture and cement system.


2006 ◽  
Vol 505-507 ◽  
pp. 1075-1080 ◽  
Author(s):  
Kuang Chyi Lee ◽  
Hsin Her Yu ◽  
Shug June Hwang ◽  
Ye Shiu Li ◽  
Min Hsun Cheng ◽  
...  

In this study, the surfaces of the multi-walled carbon nanotubes (MWNTs) were treated by acrylic acid. The acid-treated MWNTs were functionalized and were characterized by Infrared spectroscopy. The MWNTs were opened at their ends by ultrasonic treating and UV irradiating. Different adding amounts of the opened MWNTs were filled to the epoxy resin, and their mechanical properties and thermal properties were measured by Instron, impact and differential scanning calorimeter (DSC), etc. The optimum adding amount of MWNTs to the epoxy resin is 2.0%, which is according to the parameters obtained from mechanical testing and Tg. The activation energy of the epoxy resin during curing can be calculated from infrared spectra according to the change of the epoxide band. The electrical conductivity of the MWNTs-filled composites was increased with proper (12.87%) amount of MWNTs adding, this is due to the networks constructed between MWNTs completely.


2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Seyed Ali Mirsalehi ◽  
Amir Ali Youzbashi ◽  
Amjad Sazgar

AbstractIn this study, epoxy hybrid nanocomposites reinforced by carbon fibers (CFs) were fabricated by a filament winding. To improve out-of-plane (transverse) mechanical properties, 0.5 and 1.0 Wt.% multi-walled carbon nanotubes (MWCNTs) were embedded into epoxy/CF composites. The MWCNTs were well dispersed into the epoxy resin without using any additives. The transverse mechanical properties of epoxy/MWCNT/CF hybrid nanocomposites were evaluated by the tensile test in the vertical direction to the CFs (90º tensile) and flexural tests. The fracture surfaces of composites were studied by scanning electron microscopy (SEM). The SEM observations showed that the bridging of the MWCNTs is one of the mechanisms of transverse mechanical properties enhancement in the epoxy/MWCNT/CF composites. The results of the 90º tensile test proved that the tensile strength and elongation at break of nanocomposite with 1.0 Wt.% MWCNTs improved up to 53% and 50% in comparison with epoxy/CF laminate composite, respectively. Furthermore, the flexural strength, secant modulus, and elongation of epoxy/1.0 Wt.% MWCNT/CF hybrid nanocomposite increased 15%, 7%, and 9% compared to epoxy/CF laminate composite, respectively.


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