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Book ChapterDOI

Mechanical properties of isolated carbon nanotube

01 Jan 2018-Vol. 173, pp 173-199
TL;DR: In this article, the elastic and inelastic properties of isolated single and multi-walled carbon nanotubes, determined using tedious experiments and elaborated computational methods, and their dependence on nanotube physical/chemical properties.
Abstract: Due to their exceptionally high specific strength and specific stiffness, single- and multiwalled carbon nanotubes (SWCNTs and MWCNTs) are widely used as reinforcement in metallic, ceramic, and high-performance polymer matrices. The mechanical properties, including stiffness, strength, and bending characteristics, of carbon nanotubes (CNTs) are greatly influenced by a number of factors, including CNT diameter, chirality, number of concentric walls in MWCNTs, chemical functionalization, surface defects, and so forth. However, the challenges associated with the separation of a single CNT and its experimental characterization lead to less reliable and varying estimations of mechanical properties. This chapter presents a careful overview of the elastic and inelastic mechanical properties of isolated single- and multiwalled carbon nanotubes, determined using tedious experiments and elaborated computational methods, and their dependence on nanotube physical/chemical properties.
Citations
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Journal ArticleDOI
TL;DR: In this article, the electrical, mechanical and thermal properties of ultrahigh-molecular-weight polyethylene (UHMWPE) nanocomposites reinforced with 0.1 and 10.0% graphene nanoplatelets are reported.
Abstract: Here, we report the electrical, mechanical and thermal properties of ultrahigh-molecular-weight polyethylene (UHMWPE) nanocomposites reinforced with 0.1 wt% to 10 wt% of graphene nanoplatelets (GNP). The electrical conductivity of GNP/UHMWPE nanocomposites shows percolation threshold at 3.0 wt% of GNP. A significant increase in electrical conductivity from 10−15 S cm−1 for neat UHMWPE to 10−5 S cm−1 at 3.0 wt% GNP loading of GNP/UHMWPE nanocomposite (i.e. 10 orders of magnitude higher) is due to the formation of an almost three-dimensional conductive network. The highest value of electrical conductivity (1.09 S cm−1) is observed at 10.0 wt% of GNP loading. The elastic modulus and yield strength increase by 30% and 21%, for the addition of 0.5 wt% and 1.0 wt% of GNP, respectively, while fracture toughness and the ultimate tensile strength decrease significantly above 0.5 wt% GNP loading. This study demonstrates the fabrication of GNP/UHMWPE bio-nanocomposites, which exhibit electrical properties useful for smart biomedical implants.

61 citations

Journal ArticleDOI
TL;DR: In this paper, the authors report highly strain-tolerant and sensitive strain sensors based on carbon nanostructures (CNS)-polydimethylsiloxane (PDMS) nanocomposites.
Abstract: Here, we report highly strain-tolerant and sensitive strain sensors based on carbon nanostructures (CNS)-polydimethylsiloxane (PDMS) nanocomposites. CNS consist of clusters of aligned multiwall carbon-nanotubes (MWCNT) with high degree of entanglement and wall sharing between nanotubes. The unique features of CNS result in nanocomposites with very low electrical percolation threshold (0.05 wt% CNS), strong linear-piezoresistive-response up to 110% strain, and high sensitivity with gauge factor ranging from 8 to 47. We also present a simple analytical model for predicting resistivity evolution as a function of stretch considering incompressible hyperelastic behavior of CNS/PDMS nanocomposites. CNS/PDMS nanocomposites also show good hysteresis performance and stability up to 100 repetitive stretch/release cycles for 30% maximum strain. Tunable sensitivity and linear piezoresistivity coupled with high stretchability of CNS/PDMS nanocomposites demonstrated here suggest their potential for applications in wearable health and fitness monitoring devices.

58 citations

Journal ArticleDOI
TL;DR: High sensitivity of CNT/UHMWPE nanocomposites coupled with linear piezoresistive response up to 100% strain demonstrates their potential for application in artificial implants as a self-sensing material.

53 citations

Journal ArticleDOI
TL;DR: In this article, carbon nanotubes (CNTs) and graphene nanoplatelets (GNP) are combined with UHMWPE to form a nearly two-dimensional conductive network.
Abstract: Ultra-high molecular weight polyethylene (UHMWPE)-based conductive nanocomposites with reduced percolation and tunable piezoresistive behavior were prepared via solution mixing followed by compression molding using carbon nanotubes (CNT) and graphene nanoplatelets (GNP). The effect of varying wt% of GNP with fixed CNT content (0.1 wt%) on the mechanical, electrical, thermal and piezoresistive properties of UHMWPE nanocomposites was evaluated. The combination of CNT and GNP enhanced the dispersion in UHMWPE matrix and lowered the probability of CNT aggregation as GNP acted as a spacer to separate the entanglement of CNT with each other. This has allowed the formation of an effective conductive path between GNP and CNT in UHMWPE matrix. The thermal conductivity, degree of crystallinity and degradation temperature of the nanocomposites increased with increasing GNP content. The elastic modulus and yield strength of the nanocomposites were improved by 37% and 33%, respectively, for 0.1/0.3 wt% of CNT/GNP compared to neat UHMWPE. The electrical conductivity was measured using four-probe method, and the lowest electrical percolation threshold was achieved at 0.1/0.1 wt% of CNT/GNP forming a nearly two-dimensional conductive network (critical value, t = 1.20). Such improvements in mechanical and electrical properties are attributed to the synergistic effect of the two-dimensional GNP and one-dimensional CNT which limits aggregation of CNTs enabling a more efficient conductive network at low wt% of fillers. These hybrid nanocomposites exhibited strong piezoresistive response with sensitivity factor of 6.2, 15.93 and 557.44 in the linear elastic, inelastic I and inelastic II regimes, respectively, for 0.1/0.5 wt% of CNT/GNP. This study demonstrates the fabrication method and the self-sensing performance of CNT/GNP/UHMWPE nanocomposites with improved properties useful for orthopedic implants.

46 citations

Journal ArticleDOI
TL;DR: The facile green-chemistry approach reported here can be readily applied to any other 1D and 2D materials and solves key challenges associated with existing buckypaper manufacturing methods.
Abstract: A combination of carbon nanotubes (CNT) and graphene in the form of macroscopic hybrid buckypaper (HBP), exhibits a unique set of properties that can be exploited for many emerging applications. Here, we present a simple, inexpensive and scalable approach for the synthesis of highly conductive auxetic graphene/CNT HBP via wet-filtration-zipping and demonstrate the electrical, electrochemical and mechanical performance (tensile, mode I and mode III fracture) of synthesized HBP. An overall increase in electrical conductivity of 247% is observed for HBP (50 wt.% graphene and 50 wt.% CNT) as compared to BP (100 wt.% CNT) due to effective electronic percolation through the graphene and CNT. As a negative electrode for lithium-ion batteries, HBP shows 50% higher gravimetric specific capacity and 89% lower charge transfer resistance relative to BP. The graphene content in the HBP influences the mechanical performance providing an auxetic structure to HBP with large negative Poisson's ratio. The facile green-chemistry approach reported here can be readily applied to any other 1D and 2D materials and solves key challenges associated with existing buckypaper manufacturing methods. The potential of the synthesis method to integrate with current cellulose paper manufacturing technology and its scalability demonstrate the novelty of the work for industrial scale production.

20 citations