A comparative study of fracture behavior between carbon black/poly(ethylene terephthalate) and multiwalled carbon nanotube/poly(ethylene terephthalate) composite films (original) (raw)
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Among the numerous potential uses of carbon nanotubes (CNT), its utilization to fortify polymers was given careful consideration. This reason can be because of the remarkable firmness, magnificent quality, and the low thickness of CNT. This has given various chances to the innovation of new material frameworks for applications requiring high quality and high modulus. Exact control over preparing factors, including safeguarding flawless CNT structure, uniform scattering of CNT inside the polymer grid, compelling filler– lattice interfacial communications, and arrangement/introduction of polymer chains/CNT, add to the composite strands' unrivalled properties. Consequently, manufacture techniques assume an imperative part in deciding the composite filaments' microstructure and extreme mechanical conduct. The present best in the class of polymer/CNT elite composite filaments, particularly concerning processing– structure– execution, were looked into in this commitment. Future re...
The present study is concerned with a method for producing a reinforced polymer by introducing Carbon Nanotube into the polymeric host. It aims to investigate the tensile characteristics of Multiwall Carbon Nanotubes (MWCNTs) reinforced epoxy composites. Tensile test specimens of the composite were fabricated by increasing concentration of surface modified MWCNTs using molding method at room temperature. The investigation clearly exhibits the 1.25wt.% of epoxy/MWCNTs nanocomposites have enhanced tensile characteristics. These results suggest that targeted chemical modification of the carbon nanotube surface is an effective way to enhance the mechanical properties of carbon nanotube-polymer composites. The optimum loading of MWCNTs in polymeric host has been evaluated.
High strain rate behavior of multi-walled carbon nanotubes–polycarbonate composites
Composites Part B: Engineering, 2013
Multi-walled carbon nanotubes-polycarbonate composites (MWCNT-PC) were prepared by a two-step method of solvent casting followed by compression molding and their dynamic impact strength was studied. Split Hopkinson Pressure Bar (SHPB) was deployed as the instrument for impact testing of the composite samples. The impact tests were performed under varying strain rates ranging from 1096 to 4017/s. The present studies report the stress-strain behavior of MWCNT-PC composites under a high strain rate of 2000-2600/s. A comparison of stress at various strains ranging from 5% to 20% was done by varying MWCNT concentration in the range 0.1, 0.5, 1, 2 and 5 wt.% in PC. Stress tolerance of these composites was studied to analyze effectiveness of small amounts of carbon nanotubes (CNTs) for impact/stress absorption in comparison to pure PC samples. It was found that the stress behavior for specific strains varies with concentration of CNTs in polycarbonate. At very low (about 0.1 wt.%) and high concentrations (about 5 wt.%) of carbon nanotubes the stress did not vary much as compared to pure PC for the above mentioned strain range. At concentration levels of 0.5, 1 and 2 wt.% CNTs, the impact absorption (nearly 105 MPa) increased by 10-20% as compared to pure PC (nearly 90 MPa) depending upon the amount of strain in the samples. The role of functionalized CNTs in impact studies was also studied by using 0.5 wt.% and 2 wt.% functionalized MWCNT. The use of functionalized CNTs was found to result in reduced impact absorption (nearly 95 MPa) as compared to as-synthesized CNTs (nearly 105 MPa). The effect of concentration of CNTs on impact strength of MWCNT-PC composites was analyzed by studying the SEM images of composite samples after impact.
In this study, the nominal tensile strength, Young's modulus and Weibull scale and shape parameter of the nominal tensile strength distribution of the MWCNTs synthesized by a thermal chemical vapor deposition (CVD) method were investigated by conducting uniaxial tensile tests. In addition, the structural defects which induced the failure of the MWCNTs were observed by a transmission electron microscope (TEM). TEM observations revealed that the MWCNTs exhibited several types of structural defects: discontinuous flaws such as holes, kinks and bends and remnant catalysts even though crystalline graphene layers were aligned with the MWCNT axis. The nanotube tested in this study fractured at the structural defects such as discontinuous flaws and kinks and bends, suggesting that the tensile strength of the CVD-grown MWCNTs used in this study was dominated by the above-mentioned structural defects. The tensile-loading experiments demonstrated that the nominal tensile strength, Young's modulus and Weibull scale and shape parameter of the as-grown MWCNTs were 5.2 ± 2.1 GPa, 210 ± 150 GPa, 5.9 GPa and 2.7, respectively. The MWCNTs used in this study showed larger Weibull scale parameter values compared with both the CVD-grown and arc-discharge-grown MWCNTs evaluated an earlier study. This suggested that there was an optimal nanotube structure for increasing nominal tensile strength; not too weak but also not too strong inter-tube coupling to permit an adequate load transfer between the nanotube walls and thus a consequent clean break fracture. We also investigated the effects of the thermal annealing on the mechanical properties of the MWCNTs. The structural changes observed after annealing led to no significant impact on the nominal tensile strength of the MWCNTs, which was mainly due to incomplete removal of the structural defects by thermal annealing.
Mechanical Engineering Journal, 2017
In this study, the nominal tensile strength, Young's modulus and Weibull scale and shape parameter of the nominal tensile strength distribution of the MWCNTs synthesized by a thermal chemical vapor deposition (CVD) method were investigated by conducting uniaxial tensile tests. In addition, the structural defects which induced the failure of the MWCNTs were observed by a transmission electron microscope (TEM). TEM observations revealed that the MWCNTs exhibited several types of structural defects: discontinuous flaws such as holes, kinks and bends and remnant catalysts even though crystalline graphene layers were aligned with the MWCNT axis. The nanotube tested in this study fractured at the structural defects such as discontinuous flaws and kinks and bends, suggesting that the tensile strength of the CVD-grown MWCNTs used in this study was dominated by the above-mentioned structural defects. The tensile-loading experiments demonstrated that the nominal tensile strength, Young's modulus and Weibull scale and shape parameter of the as-grown MWCNTs were 5.2 ± 2.1 GPa, 210 ± 150 GPa, 5.9 GPa and 2.7, respectively. The MWCNTs used in this study showed larger Weibull scale parameter values compared with both the CVD-grown and arc-discharge-grown MWCNTs evaluated an earlier study. This suggested that there was an optimal nanotube structure for increasing nominal tensile strength; not too weak but also not too strong inter-tube coupling to permit an adequate load transfer between the nanotube walls and thus a consequent clean break fracture. We also investigated the effects of the thermal annealing on the mechanical properties of the MWCNTs. The structural changes observed after annealing led to no significant impact on the nominal tensile strength of the MWCNTs, which was mainly due to incomplete removal of the structural defects by thermal annealing.
STRUCTURE AND PROPERTIES OF CARBON NANOTUBE REINFORCED NANOCOMPOSITES
2000
Carbon nanotubes (CNT) possess many unique characteristics that promise to revolutionize the world of structural ma- terials resulting in significant impact on our capability to build lighter, smaller and higher performance structures for aerospace and many other industrial ap- plications. When the CNT are aligned, micromechanical studies showed the po- tential of an order of magnitude increase in mechanical properties
Small but strong: A review of the mechanical properties of carbon nanotube-polymer composites
Carbon, 2006
The superlative mechanical properties of carbon nanotubes make them the filler material of choice for composite reinforcement. In this paper we review the progress to date in the field of mechanical reinforcement of polymers using nanotubes. Initially, the basics of fibre reinforced composites are introduced and the prerequisites for successful reinforcement discussed. The effectiveness of different processing methods is compared and the state of the art demonstrated. In addition we discuss the levels of reinforcement that have actually been achieved. While the focus will be on enhancement of Young's modulus we will also discuss enhancement of strength and toughness. Finally we compare and tabulate these results. This leads to a discussion of the most promising processing methods for mechanical reinforcement and the outlook for the future.