Synergistic Effect Of Carbon Nanotubes Research Articles

Thermal and Morphological Study of Epoxy Matrix with Chemical and Physical Hybrid of Nanoclay/Carbon Nanotube

Synergistic effects of nanoclay (NC) and carbon nanotube (CNT) as a physical and chemical hybrid on the properties of epoxy matrix were studied. The chemical hybrid of CNT-NC (CNC) was synthesized by high-temperature decomposition of methane on NC supports. The formation of CNTs on the NC surface was confirmed by transmission electron microscopy, scanning electron microscopy (SEM) and Raman spectroscopy. As-prepared CNCs were subsequently added into an epoxy matrix to make epoxy-CNC composites. The mixture of purified CNTs and NC as the physical hybrid of CNT-NC (PNC) was introduced into the epoxy matrix in order to fabricate epoxy-PNC composites. The relationship between the type of filler with the thermal and morphological performance of the epoxy-CNT-NC composite hybrids was investigated. The exfoliation characteristics of NCs and CNTs in epoxy nanocomposites were analyzed using x-ray spectroscopy (EDX) and SEM studies, respectively. Thermal behavior of the epoxy nanocomposites was studied by thermo-gravimetric-differential thermal analysis (TGA/DTG), the heat deflection temperature (HDT) test and dynamic mechanical analysis (DMA). The results indicated that the thermal characteristics of the epoxy including the degradation temperature (T deg), HDT and glass transition temperature (T g) relatively increased with the introduction of all the nanofillers, NC, CNT, PNC and CNC. The synergistic effects of CNT and NC were found to be more marked for the chemical hybrid compared to the physical one. In the case of CNC, it was observed that the CNTs attached to the clay sheets form a unique structure in which a 2D NC has several 1D CNTs attached to it. The enhanced homogeneous dispersion of NCs and CNTs in epoxy-CNC was clearly observed compared to epoxy-PNC.

Synergistic effect of carbon nanotubes and copper particles in an epoxy-based nanocomposite using electroless copper deposited carbon nanotubes: Part I – Mechanical properties

In this study, the mechanical properties of epoxy nanocomposites reinforced by different contents of copper (Cu)-coated multiwalled carbon nanotubes (MWCNTs) are evaluated and discussed. Electroless deposition process is employed for Cu metallization of the MWCNTs. The functionalization step (as one of the prerequisite steps for deposition process) is carried out using hybrid approach with Triton and HNO3. The functionalized and Cu deposited MWCNTs are characterized by Fourier transform infrared, Raman spectroscopy, thermogravimetric analysis, atomic absorption spectroscopy, and scanning electron microscopy. For comparison, functionalized MWCNT–epoxy nanocomposites are also fabricated through the same fabrication process. Our results indicate that applying functionalized MWCNTs are more effective for enhancing tensile properties. On the contrary, Cu-coated MWCNT–epoxy nanocomposites show more improvement in flexural and impact behaviors. Accordingly, compared to neat epoxy, enhancement of up to ∼51% and ∼95% respectively in flexural strength and impact resistance are achieved by the addition of 0.1 wt% Cu-coated MWCNT.

Effects of Carbon Fillers on Crystallization Properties and Thermal Conductivity of Poly(phenylene sulfide)

Differential scanning calorimetry and polarized optical microscopy methods were used to investigate the crystallization behavior and isothermal crystallization kinetics of poly(phenylene sulfide) (PPS)/carbon nanotube (CNT) and PPS/CNT/carbon fiber (CF) composites. In this article, the influences of CNT and CF on PPS crystallization behavior are explained. The thermal conductivity properties of composites were studied using the laser flash method. The results show that CNT increased crystallization temperature and rate and thermal conductivity greatly improved at 8 wt.% CNT content. In addition, the crystallization and thermal performance of PPS are significantly improved via synergistic effects of CNT and CF in the composites.

Synergistic effects of carbon nanotubes and carbon black on the fracture and fatigue resistance of natural rubber composites

ABSTRACTThe quasi‐static fracture and dynamic fatigue behaviors of natural rubber composites reinforced with hybrid carbon nanotube bundles (CNTBs) and carbon black (CB) at similar hardness values were investigated on the basis of fracture mechanical methods. Mechanical measurement and J‐integral tests were carried out to characterize the quasi‐static fracture resistance. Dynamic fatigue tests were performed under cyclic constant strain conditions with single‐edged notched test pieces. The results indicate that synergistic effects between CNTBs and CB on the mechanical properties, fracture, and fatigue resistance were obtained. The composite reinforced with 3‐phr CNTBs displayed the strongest fatigue resistance. The synergistic mechanisms and dominating factors of quasi‐static and dynamic failure, such as the dispersion state of nanotubes, hybrid filler network structure, strain‐induced crystallization, tearing energy input, and viscoelastic hysteresis loss, were examined. The weakest fatigue resistance of the composite filled with 5‐phr CNTBs was ascribed to its strikingly high hysteresis, which resulted in marked heat generation under dynamic fatigue conditions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42075.

Competitive adsorption of heavy metal ions on carbon nanotubes and the desorption in simulated biofluids

Carbon nanotubes (CNTs) had meaningful adsorption capacities for Pb2+, Cu2+, Zn2+ and Cd2+, while Pb2+ showed the highest adsorption in the competitive adsorption evaluations. The desorption behaviors of heavy metal ions were completely different in various biofluids, where the desorption was significantly influenced by pH and the presence of proteins/other cations. The desorption was most effective in simulated stomach juice, and much less effective in other simulated biofluids. More Pb2+ stuck to CNTs than others, resulting in less desorption. Interestingly, the competitive desorption behaviors of four ions were largely changed comparing to the individual desorption behaviors. The implications to the biosafety evaluations and synergistic effects of CNT are discussed.

Synergistic effect of carbon nanotubes and clay platelets in reinforcing properties of silicone rubber nanocomposites

ABSTRACTFine powders of montmorillonite (MMT)/multiwalled carbon nanotube (MWCNT) hybrids have been prepared by simple grinding of MWCNT with MMT in different weight ratios of MMT to MWCNT (10 : 1, 6 : 1, 3 : 1, 1 : 1, and 1 : 3) and characterized by wide‐angle X‐ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. These studies have established the formation of the exfoliated structures of MMT/MWCNT (1 : 1) hybrid, in which MWCNTs exist in the state of single nanotubes that are adsorbed and intercalated on the surface and in between the MMT nanoplatelets. The hybrid has subsequently been used as reinforcing nanofiller in the development of high‐performance silicone rubber (SR) nanocomposites, and a remarkably synergistic effect of MMT and MWCNT on SR properties has been observed. The tensile strength of SR containing 1% w/w of the MMT/MWCNT (1 : 1) hybrid is improved by 215%, whereas the SR filled with MMT or MWCNT alone showed an improvement of 46 and 25%, respectively, over that of unfilled SR. In addition, SR/1 wt % MMT/MWCNT (1 : 1) nanocomposites also exhibit the maximum improvement in thermal stability corresponding to 10% weight loss by 70°C, crystallization and melting temperatures increased by 8 and 6°C as inferred from thermogravimetric analysis and differential scanning calorimetry, respectively. This approach is promising for the preparation of high‐performance SR nanocomposites by using different dimension nanofillers together. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41818.

Synergistic effect of carbon nanotubes and layered double hydroxides on the mechanical reinforcement of nylon-6 nanocomposites

Synergistic effect in network formation of nylon-6 (PA6) nanocomposites containing one dimensional (1D) multi-walled carbon nanotubes (CNTs) and two dimensional (2D) layered double hydroxide (LDH) platelets on improving the mechanical properties has been studied. Mechanical tests show that, with incorporation of 1 wt% LDHs and 0.5 wt% CNTs, the tensile modulus, the yield strength as well as the hardness of the ternary composite are greatly improved by about 230%, 128% and 110% respectively, as compared with neat PA6. This is mainly attributed to the unique, strong interactions between the CNTs and the LDHs as well as the jammed network-like structure thus formed between the nanofillers, as confirmed by the morphological observations. As compared with the binary nanocomposites, a much enhanced solid-like behavior in the terminal region of the rheological curves can clearly be observed for the ternary system, which also indicates the formation of a percolating filler network.

Synergistic effect of carbon nanotubes in combination with magnesium hydroxide on the flame retardant poly(ethylene-co-vinyl acetate)

Abstract To investigate the synergistic effect of carbon nanotubes (CNTs) in combination with magnesium hydroxide (MH) on the flame retardant poly(ethylene-co-vinyl acetate) (EVA), a series of EVA-based composites filled with CNTs, MH, a mixture of MH and CNTs, and MH-modified CNTs (MH-CNTs) were prepared. Characterizations of the fillers and the composites were performed by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, and cone calorimetry. The results indicated that the presence of CNTs affected the size of the attaching MH, which was decreased to around 20 nm. MH also had an enlarged special surface area in the MH-CNTs. A synergism was found in the MH-CNTs on the thermal retardant EVA composites due to the interaction between MH and CNTs.

Synergistic effect of carbon nanotubes and n-butyl glycidyl ether on matrix modification for improvement of tensile performance of glass fiber/epoxy composites

In this work, an epoxy resin was modified by stiff multi-walled carbon nanotubes (MWCNTs) and soft n-butyl glycidyl ether (BGE) and the modified epoxy resins were employed as the matrices for improvement of the tensile performance of glass fiber reinforced composites. The results indicated that the simultaneous addition of MWCNTs and BGE led to the greatest enhancements in the composite strength and modulus, demonstrating that their simultaneous introduction yielded a synergistic effect on the matrix modification for the improvement of the tensile performance of the GF/epoxy composites. The scanning electron microscope observations showed that the modified epoxy resins were substantially coated on the surfaces of GFs while the un-modified matrix was lightly attached on the GFs. The enhancements in the composite tensile performance were attributed to two aspects of enhanced GF strength/modulus and improved interfacial adhesion for the modified matrix compared to the un-modified case.

Significantly improving infrared light-induced shape recovery behavior of shape memory polymeric nanocomposite via a synergistic effect of carbon nanotube and boron nitride

The present work studies the thermomechanical properties and infrared light-induced shape memory effect (SME) in shape memory polymer (SMP) nanocomposite incorporated with carbon nanotube (CNT) and boron nitride. The combination of CNT and boron nitride results in higher glass transition temperature, mechanical strength and thermomechanical strength. While CNTs are employed to improve the absorption of infrared light and thermally conductive property of SMP, boron nitrides facilitate heat transfer from CNTs to the polymer matrix and thus to enable fast response. A unique synergistic effect of CNT and boron nitride was explored to facilitate the heat transfer and accelerate the infrared light-induced shape recovery behavior of the shape memory polymeric nanocomposite.

Synergistic Effect of Carbon Nanotube and Polyethersulfone on Flame Retardancy of Carbon Fiber Reinforced Epoxy Composites

By using resin transfer molding (RTM) technology, carbon fiber (CF) reinforced epoxy composites (CF/Epoxy, CF/PES/Epoxy, and CF/PES-MWCNT/Epoxy) are prepared. CF is the reinforced fiber, Epoxy is the epoxy matrix, and PES-MWCNT is the multiwall carbon nanotubes doped polyethersulfone film. Their fire behavior is systematically studied according to limiting oxygen index (LOI), vertical burning test (UL94), and cone calorimeter test (CCT). Their thermal degradation process, kinetics, and flame retardant mechanism are investigated from thermogravimetric analysis (TGA) and scanning electronic microscopy (SEM). The results show that these composites can reach the highest UL94 rating with the 5VA level achieved. Moreover, introduction of PES-MWCNT improves the LOI values, reduces the total smoke production (TSP), and slightly decreases peak of heat release rate (PHRR) and total heat release (THR). This improvement in the flame retardancy results from the increased degradation activation energy (Ea) and formatio...

Synergistic effects of carbon nanotubes and exfoliated graphite nanoplatelets for electromagnetic interference shielding and soundproofing

ABSTRACTPolypropylene/carbon nanotube/exfoliated graphite nanoplatelet (PP/CNT/xGnP) composites have been fabricated to evaluate their electromagnetic interference shielding effectiveness (EMI SE) and soundproofing. An EMI SE of 36.5 dB at 1250 MHz was measured for the 80/10/10 wt % PP/CNT/xGnP composite; its sound transmission loss was more than 5 dB higher than that for pure PP at low frequencies (520–640 Hz). These results indicate simultaneous EMI SE and soundproofing. Transmission electron microscopy was used to study the microstructure and to probe synergetic effects between the CNTs and xGnPs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3947–3951, 2013

Synergistic effect of carbon nanotubes and carbon black on electrical conductivity of PA6/ABS blend

Abstract In this work, conductive fillers of carbon nanotubes (CNTs), carbon black (CB), and hybrid CNTs/CB were introduced into polyamide 6/acrylonitrile–butadiene–styrene (PA6/ABS) blend to prepare different conductive composites, respectively. The dispersion states of conductive fillers and the morphologies of the composites were characterized using a scanning electron microscope. The rheological properties and crystallization behaviors of representative samples were investigated using a rheometer and a differential scanning calorimetry, respectively. The electrical resistivity of different composites was measured and the results showed that CNTs and CB exhibited a synergistic effect in decreasing the electrical resistivity of the composites due to the selective distribution of both CNTs and CB in the PA6 phase and the formation of cocontinuous morphology. Furthermore, the effect of adding CNTs (or CB) on the electrical conductivity of composites already containing CB (or CNTs) was comparatively investigated.

Conductive Rubber Nanocomposites as Tensile and Pressure Sensors

A conductive silicone rubber (SR) composite, filled with both carbon nanotubes (CNT) and carbon black (CB) is prepared by a simple ball milling method. Because of the good dispersion and synergistic effects of CNT and CB, the SR composite shows improvement in mechanical properties. As well, due to the assembly of conductive pathways generated by the CNT and CB, the nanocomposite becomes highly conductive at a comparatively low concentration, with very high sensitivity for tensile and compressive stress. These outstanding properties show that the SR composite has potential applications in tensile and pressure sensors.

Silicone rubber nanocomposites containing a small amount of hybrid fillers with enhanced electrical sensitivity

A conductive silicone rubber (SR) composite, filled with both carbon nanotubes (CNTs) and carbon black (CB) is prepared by a simple ball milling method. Because of the good dispersion and synergistic effects of CNT and CB, the SR composite (SR with 2.5phr CB and 1.0phr CNT hybrid fillers) shows improvement in mechanical properties such as tensile strength and strain to failure. As well, due to the assembly of conductive pathways generated by the CNT and CB, the nanocomposite becomes highly conductive at a comparatively low concentration, with high sensitivity for tensile and compressive stress. Long-term measurement of properties shows that the SR composite maintains the excellent electrical properties under different strain histories. These outstanding properties show that the SR composite has potential applications in tensile and pressure sensors.

Synergistic effect of carbon nanotubes and decabromodiphenyl oxide/Sb 2O 3 in improving the flame retardancy of polystyrene

Brominated flame retardant polystyrene composites were prepared by melt blending polystyrene, decabromodiphenyl oxide, antimony oxide, multi-wall carbon nanotubes and montmorillonite clay. Synergy between carbon nanotubes and clay and the brominated fire retardant was studied by thermogravimetric analysis, microscale combustion calorimetry and cone calorimetry. Nanotubes are more efficient than clay in improving the flame retardancy of the materials and promoting carbonization in the polystyrene matrix. Comparison of the results from the microscale combustion calorimeter and the cone calorimeter indicate that the rate of change of the peak heat release rate reduction in the microscale combustion calorimeter was slower than that in the cone. Both heat release capacity and reduction in the peak heat release rate in the microscale combustion calorimeter are important for screening the flame retardant materials; they show good correlations with the cone parameters, peak heat release rate and total heat released.

Synergistic effect of carbon nanotube and clay for improving the flame retardancy of ABSresin

Synergistic effect between multi-walled carbon nanotubes (MWNTs) and clay on improvingthe flame retardancy of acrylonitrile–butadiene–styrene (ABS) resin was studied.Flammability properties measured by a cone calorimeter revealed that incorporation ofclay and MWNTs into ABS resin significantly reduced the peak heat releaserate (PHRR) and slowed down the whole combustion process compared to theindividually filled system based on clay or MWNTs. The flame retardancy of theABS/clay/MWNTs nanocomposites was strongly affected by the formation of anetwork structure. Linear viscoelastic properties of the ABS nanocomposites showedthat the coexistence of clay and MWNTs can enhance the network structurewhich can hinder the movement of polymer chains and improve flame retardancy.From transmission electron microscope analysis, MWNTs were shortened aftercombustion and there was no significant change in their diameters. For chars ofABS/clay/MWNTs nanocomposites, some MWNTs ran across between clay layers,indicating a strong interaction existed between clay and MWNTs. The existence of clayenhanced the graphitization degree of MWNTs during combustion. Clay can assistthe elimination of dislocations and defects and the rearrangement of crystallites.Al2O3, one of the components of clay, acts as the catalyst of graphitization.