S042013 Fabrication and Evaluation of Carbon Nanotube/Alumina Composites by Pressureless Sintering and Influence of Carbon Nanotube Tensile Strength on Their Composite Mechanical Properties

This paper aims to investigate the effect of co-milling-assisted exfoliation of graphite into polyethylene and alumina matrices on the mechanical properties of the composites. Tensile mechanical properties of composite materials based on polyethylene reinforced with graphite and graphite-derived fillers at 0–0.75 wt% loading were investigated, while hardness and flexural properties of alumina composites with 0.25 wt% loading of the same additives were assessed. Exfoliated graphite, applied at 0.25–0.75 wt% in pre-exfoliated form or in a co-milling-assisted fashion, has been demonstrated to be effective in enhancing the tensile strength of polyethylene composites. Similar enhancement in hardness and flexural properties was observed in alumina composites with 0.25 wt% loading of the exfoliated graphite. Co-milling-assisted exfoliated graphite nanoplatelets additive introduction has been found to effect a more desirable mechanical properties enhancement in the composites investigated in this study.

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Influence of Defect Number, Distribution Continuity and Orientation on Tensile Strengths of the CNT-Based Networks: A Molecular Dynamics Study

Nanoscale Research Letters ◽

10.1186/s11671-022-03656-w ◽

2022 ◽

Vol 17 (1) ◽

Author(s):

Xian Shi ◽

Xiaoqiao He ◽

Ligang Sun ◽

Xuefeng Liu

Keyword(s):

Mechanical Properties ◽

Molecular Dynamics ◽

Tensile Strength ◽

Carbon Nanotube ◽

Electronic Devices ◽

Underlying Mechanism ◽

Force Transmission ◽

Tensile Direction ◽

Defect Number ◽

Number Distribution

Abstract Networks based on carbon nanotube (CNT) have been widely utilized to fabricate flexible electronic devices, but defects inevitably exist in these structures. In this study, we investigate the influence of the CNT-unit defects on the mechanical properties of a honeycomb CNT-based network, super carbon nanotube (SCNT), through molecular dynamics simulations. Results show that tensile strengths of the defective SCNTs are affected by the defect number, distribution continuity and orientation. Single-defect brings 0 ~ 25% reduction of the tensile strength with the dependency on defect position and the reduction is over 50% when the defect number increases to three. The distribution continuity induces up to 20% differences of tensile strengths for SCNTs with the same defect number. A smaller arranging angle of defects to the tensile direction leads to a higher tensile strength. Defective SCNTs possess various modes of stress concentration with different concentration degrees under the combined effect of defect number, arranging direction and continuity, for which the underlying mechanism can be explained by the effective crack length of the fracture mechanics. Fundamentally, the force transmission mode of the SCNT controls the influence of defects and the cases that breaking more force transmission paths cause larger decreases of tensile strengths. Defects are non-negligible factors of the mechanical properties of CNT-based networks and understanding the influence of defects on CNT-based networks is valuable to achieve the proper design of CNT-based electronic devices with better performances. Graphical Abstract

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The influence of functionalization time of carbon nanotube on the mechanical properties of the epoxy composites

Journal of Composite Materials ◽

10.1177/0021998317701988 ◽

2017 ◽

Vol 51 (12) ◽

pp. 1693-1701 ◽

Cited By ~ 4

Author(s):

EA Zakharychev ◽

EN Razov ◽

Yu D Semchikov ◽

NS Zakharycheva ◽

MA Kabina

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Tensile Strength ◽

Elastic Modulus ◽

Carbon Nanotube ◽

Composite Materials ◽

Polymer Composites ◽

Epoxy Composites ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

This paper investigates the structure, length, and percentage of functional groups of multi-walled carbon nanotubes (CNT) depending on the time taken for functionalization in HNO3 and H2SO4 mixture. The carbon nanotube content and influence of functionalization time on mechanical properties of polymer composite materials based on epoxy matrix are studied. The extreme dependencies of mechanical properties of carbon nanotube functionalization time of polymer composites were established. The rise in tensile strength of obtained composites reaches 102% and elastic modulus reaches 227% as compared to that of unfilled polymer. The composites exhibited best mechanical properties by including carbon nanotube with 0.5 h functionalization time.

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Prediction of tensile strength of polymer carbon nanotube composites using practical machine learning method

Journal of Composite Materials ◽

10.1177/0021998320953540 ◽

2020 ◽

pp. 002199832095354 ◽

Cited By ~ 5

Author(s):

Tien-Thinh Le

Keyword(s):

Machine Learning ◽

Mechanical Properties ◽

Tensile Strength ◽

Carbon Nanotube ◽

Polymer Matrix ◽

Mean Squared Error ◽

Gaussian Process Regression ◽

Weight Fraction ◽

Percentage Error ◽

Input Variables

This paper is devoted to the development and construction of a practical Machine Learning (ML)-based model for the prediction of tensile strength of polymer carbon nanotube (CNTs) composites. To this end, a database was compiled from the available literature, composed of 11 input variables. The input variables for predicting tensile strength of nanocomposites were selected for the following main reasons: (i) type of polymer matrix, (ii) mechanical properties of polymer matrix, (iii) physical characteristics of CNTs, (iv) mechanical properties of CNTs and (v) incorporation parameters such as CNT weight fraction, CNT surface modification method and processing method. As the problem of prediction is highly dimensional (with 11 dimensions), the Gaussian Process Regression (GPR) model was selected and optimized by means of a parametric study. The correlation coefficient (R), Willmott’s index of agreement (IA), slope of regression, Mean Absolute Percentage Error (MAPE), Root Mean Squared Error (RMSE) and Mean Absolute Error (MAE) were employed as error measurement criteria when training the GPR model. The GPR model exhibited good performance for both training and testing parts (RMSE = 5.982 and 5.327 MPa, MAE = 3.447 and 3.539 MPa, respectively). In addition, uncertainty analysis was also applied to estimate the prediction confidence intervals. Finally, the prediction capability of the GPR model with different ranges of values of input variables was investigated and discussed. For practical application, a Graphical User Interface (GUI) was developed in Matlab for predicting the tensile strength of nanocomposites.

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Correlation between Porosity and Electrical-Mechanical Properties of Carbon Nanotube Buckypaper with Various Porosities

Journal of Nanomaterials ◽

10.1155/2015/945091 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 6

Author(s):

Ling Liu ◽

Qiaoxin Yang ◽

Jingwen Shen

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Carbon Nanotube ◽

The Other ◽

Positive Pressure ◽

Filtration Method ◽

Elongation At Break ◽

Conductive Materials ◽

Wide Range ◽

Electrical Conductivities

Porous carbon nanotube (CNT) buckypapers (BPs) with various porosities were obtained by using a positive pressure filtration method. The porosity of the BPs fell into a wide range of 11.3–39.3%. Electrical conductivities and tensile mechanical properties of the prepared BPs were then measured and correlated with the porosity of the CNT BPs. Results demonstrated that the conductivities, tensile strength, and elastic modulus of the BPs could decrease by increasing their porosity. The elongation at break of the BPs on the other hand did increase significantly, suggesting improved toughness of the BPs. The obtained electrical conductivity and tensile strength of the porous BPs can reach nearly 0.6 S/m and 26 MPa, respectively, which may be potentially useful in composites reinforcement and conductive materials.

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Crystallization behavior and mechanical properties of poly(lactic acid) complex fiber toughened by carbon nanotube nanocapsules

Textile Research Journal ◽

10.1177/0040517517705629 ◽

2017 ◽

Vol 88 (14) ◽

pp. 1616-1627 ◽

Cited By ~ 2

Author(s):

Shu-qiang Liu ◽

Gai-hong Wu ◽

Yun-chao Xiao ◽

Hong-xia Guo ◽

Fen-juan Shao

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Lactic Acid ◽

Thermal Properties ◽

Carbon Nanotube ◽

Crystallization Behavior ◽

Poly Lactic Acid ◽

Acid Complex ◽

Main Obstacle ◽

Industrial Areas

Poly(lactic acid) (PLA) fiber, owing to its biocompatibility and biodegradability, could be widely used in many related industrial areas. However, high brittleness has been the main obstacle to expanding its applications. So in this paper, carbon nanotube (CNT) nanocapsules were designed to toughen PLA and further reported their effect on the crystallization behavior and mechanical properties of PLA complex fiber. These designed CNT nanocapsules successfully solved the agglomeration of CNTs within the PLA matrix as well as the compatibility issue. In addition, the morphological, mechanical, optical and thermal properties of PLA complex fibers were also studied. The addition of CNT nanocapsules obviously improved the crystallization behavior of PLA fiber. Furthermore, compared with pure PLA, the tensile strength of PLA complex fiber was enhanced by 30.62% and the elongation by 32.2%, so the designed CNT nanocapsules could be used as a toughener for PLA fiber. This research benefits the extension of PLA applications where toughness is an important factor.

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STRAIN-INDUCED CRYSTALLIZATION AND MECHANICAL PROPERTIES OF NBR COMPOSITES WITH CARBON NANOTUBE AND CARBON BLACK

Rubber Chemistry and Technology ◽

10.5254/rct.12.88955 ◽

2012 ◽

Vol 85 (2) ◽

pp. 207-218 ◽

Cited By ~ 7

Author(s):

Sang-Ryeoul Ryu ◽

Jong-Whan Sung ◽

Dong-Joo Lee

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Carbon Nanotube ◽

Carbon Black ◽

Scanning Calorimetry ◽

Multiwalled Carbon ◽

Extension Ratio ◽

The Matrix ◽

Strain Induced Crystallization ◽

Induced Crystallization

Abstract The mechanical properties and strain-induced crystallization (SIC) of elastomeric composites were investigated as functions of the extension ratio (λ), multiwalled carbon nanotube (CNT) content, and carbon black (CB) content. The tensile strength and modulus gradually increase with increasing CNT content when compared with the matrix and the filled rubbers with same amount of CB. Both properties of rubber with CB and CNT show the magnitude of each CNT and CB component following the Pythagorean Theorem. The ratio of tensile modulus is much higher than that of tensile strength because of the CNT shape/orientation and an imperfect adhesion between CNT and rubber. The tensile strength and modulus of the composite with a CNT content of 9 phr increases up to 31% and 91%, respectively, compared with the matrix. Differential scanning calorimetry (DSC) analysis reveals that the degree of SIC increases with an increase in CNT content. Mechanical properties have a linear relation with the latent heat of crystallization (LHc), depending on the CNT content. As the extension ratio increases, the glass-transition temperature (Tg) of the composite increases for CB- and CNT-reinforced cases. However, the LHc has a maximum of λ = 1.5 for the CNT-reinforced case, which relates to a CNT shape and an imperfect adhesion with rubber. Based on these results, the reinforcing mechanisms of CNT and CB are discussed.

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