Tensile properties of carbon nanotube fibres described by the fibrillar crystallite model

Abstract

This work presents a model that successfully describes the tensile properties of macroscopic fibres of carbon nanotubes (CNTs). The core idea is to treat the fibres as a network of crystallites, similar to the structure of highperformance polymer fibres, with tensile properties defined by the crystallite orientation distribution function (ODF), shear modulus and shear strength.Synchrotron small-angle X-ray scattering measurements on individual fibres are used to determine the initial ODF and its evolution during in-situ tensile testing. This enables prediction of tensile modulus, strength and fracture envelope, with remarkable agreement with experimental data for fibres produced in-house with different constituent CNTs and for different draw ratios, as well as with literature data. The parameters extracted from the model include: crystallite shear strength, shear modulus and fibril strength. These are in agreement with data for commercial high-performance fibres, although * Corresponding authors high compared with values for single-crystal graphite and short individual CNTs. The manuscript also discusses the unusually high fracture energy of CNT fibres and exceptionally high figure of merit for ballistic protection.The model predicts that small improvements in orientation would lead to superior ballistic peformance than any synthetic high-peformance fiber, with values of strain wave velocity (U 1/3 ) exceeding 1000m/s.

Elastic Damper Based on the Carbon Nanotube Bundle

“…Moreover, CNTs are flexible, lightweight, good heat and electricity conductors, thus being useful in a number of applications [12][13][14][15]. The most important mechanical applications of CNTs are high-strength ropes [2,16], fibers [17][18][19][20][21], polymer-and metal-matrix composites [22][23][24], solid lubricants [24,25], etc.…”

“…It should be pointed out that tension [2,[16][17][18][19][20][21] and compression [26][27][28][29][30][31][32][33] of vertically aligned CNT brushes and forests have been extensively studied. Note that CNTs grow in vertical direction and compression of vertically aligned CNTs means that they are compressed along their axis, while compression of horizontally aligned CNTs means that they are compressed normal to their axis.…”

Mechanical Response of Carbon Nanotube Bundle to Lateral Compression

“…In addition, they are flexible, have low weight, high thermal and electrical conductivity, which makes them very promising for a number of applications [13][14][15][16]. CNT forests are produced by means of various experimental techniques [17][18][19][20][21] and used for making super-strong ropes [7,22], fibers [23][24][25][26][27], fillers for composite materials [28][29][30], solid lubricants [30][31][32][33], etc.…”

“…Mechanical properties of vertically aligned CNT forests and brushes have been tested with respect to tension [7,[22][23][24][25][26][27] and compression [34][35][36][37][38][39][40][41]. Lateral compression of CNT bundles or isolated CNTs is also of interest [42][43][44][45][46].…”

Understanding cooperative loading in carbon nanotube fibres through in-situ structural studies during stretching

“…The present mechanical study was conducted on few-layer MWCNTs fibres, as reported in a previous work [5]. Their tensile properties were determined from a minimum of 10 conventional uniaxial tensile tests per sample type.…”