Effect Of Multi-walled Carbon Nanotube Content Research Articles

Carbon Nanotube Reinforced Intermetallic

Iron aluminides (Fe3Al) based composite with different amounts of multi-walled carbon nanotube (MWNT) have been prepared by using spark plasma sintering. Effect of MWNTs content on the mechanical properties was investigated. The compressive yield strength and fracture toughness of the 3 vol% MWNTs–Fe3Al composite, compared with the monolithic Fe3Al, were enhanced 73.6% and 40%, respectively. The main reinforced mechanisms include MWNTs pulling-out, crack deflection, bridging and MWNTs rupture. The defects and aligning direction of MWNTs in the matrix are also the factors that affect the mechanical properties of composites as prepared.

Composite Cathode Structure and Binder for High Performance Lithium-Sulfur Battery

Ball milling in combination with heat treatment was used to prepare sulfur-based composite cathode materials incorporating multi-walled carbon nanotubes (MCNTs) for Li-S battery. The structure and morphology of the as-prepared cathode materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of MCNT content and binder type on the capacity,cyclability and self-discharge behavior of a sulfur-based cathode were systematically investigated. Results show that the appropriate amount of MCNTs is 5%-8% (w,mass fraction) and the use of β-cyclodextrin as a water-soluble binder to fabricate the cathode results in the best electrochemical performance. When the Li-S battery was half charged at room temperature,there was almost no self-discharge during storage for 30 d. The charging capacity was 687.7 mAh.g-1 during the 1st cycle and 623.8 mAh.g-1 during the 100th cycle for the cathode at a current rate of 0.1C. Therefore,90.7% of the capacity was retained.

Water transport behavior of chitosan porous membranes containing multi-walled carbon nanotubes (MWNTs)

In this work, the effects of MWNTs content on water transport behaviors and tensile properties of prepared chitosan porous membranes were investigated. In the case of chitosan membrane using low molecular weight PEG6000 as a porogen, a percolation-like behavior of water transport rate was observed for the first time in composite membranes with a critical MWNTs content (5 wt%). The water flux of composite membrane with 10 wt% MWNTs (128.1 L/m 2 h) is 4.6 times that of neat one (27.6 L/m 2 h). This could be understood as due to the formation of MWNTs network located among the pore network of chitosan membrane at high MWNTs content, where the hollow nanochannel of MWNTs and their interspaces could provide a new transport channel for water. In contrary, when high molecular weight PEG10000 is used as the porogen, a decreased water flux of the prepared composite membrane is found with increase of MWNTs content. In this case, a strong compatibilizing effect of MWNTs on chitosan/PEG10000 blends is observed, resulting in a decreased pore size and poor water flux of the membranes. Furthermore, a greatly improved tensile strength of chitosan porous membranes has been achieved by adding MWNTs, no matter which molecular weight PEG is used as porogen. Our work provides a novel way to improve water flux and/or control the pore size of polymer porous membranes by using MWNTs.

Effect of chemical functionalization of multi-walled carbon nanotubes with 3-aminopropyltriethoxysilane on mechanical and morphological properties of epoxy nanocomposites

Nanocomposites based on epoxy resin and different weight percentages of unmodified, oxidized, and silanized multi-walled carbon nanotubes (MWCNTs) were prepared by cast molding method. Effects of MWCNTs content on the flexural properties were examined. The results showed that as the loading of the MWCNTs increased, improved flexural strength and flexural modulus were observed. The mechanical properties decreased when the MWCNTs content exceeded 0.2 wt.% due to agglomeration of MWCNTs. These results prove the effect of functionalization on the interfacial adhesion between epoxy and MWCNTs. This was further confirmed by morphology study of fractured surfaces of nanocomposites by SEM and TEM.

Mechanical and thermal properties of epoxy nanocomposites reinforced with amino-functionalized multi-walled carbon nanotubes

The functionalized multi-walled carbon nanotubes (MWNTs) with amino groups were prepared after such steps as oxidation, the addition of carboxyalkyl radicals, acylation and amidation. Besides oxidated-MWNTs/epoxy nanocomposites, amino-functionalized MWNTs/epoxy nanocomposites, in which MWNTs with amino groups acted as a curing agent and covalently attached into the epoxy matrix, were fabricated. Subsequently, the effects of MWNT content on the mechanical and thermal properties for the two systems were investigated. It is found that both the tensile strength and impact strength enhance with the increase of MWNT addition, and the most significant improvement of the tensile strength (+51%) and especially impact strength (+93%) is obtained with amine-treated MWNTs at an 1.5 wt.% content. Moreover, the thermal stability of the nanocomposites also distinctly improves. The improvement of the properties of the amine-treated MWNTs system is more remarkable than those of o-MWNTs system. The reasons for these changes were discussed.