Impact of the spatial distribution of high content of carbon nanotubes on the electrical conductivity of glass fiber fabrics/epoxy composites fabricated by RTM technique (original) (raw)
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Journal of Applied Physics, 2013
Multiwall carbon nanotubes (CNTs) were directly grown on woven carbon fibers using chemical vapor deposition technique and iron acetate as a catalyst. These CNTs grown woven carbon fibers were further infused with epoxy resin to fabricate fiber reinforced nanocomposites. Both electric and mechanical properties of these composites were studied and found that the electric resistivity of composite reduced significantly as the amount of CNTs on woven carbon fiber increased. For the neat composite without CNTs, the resistivity observed was 25 XÁm, while it was only 0.2 XÁm for the composite with 3.3 wt. % of CNTs grown on woven carbon fiber. The flexure test results showed a 34% increase in strength and 126% increase in stiffness for 1.65 wt. % CNTs grown on woven carbon fiber. V C 2013 AIP Publishing LLC. [http://dx.
Polymer Composites, 2015
Hybrid composites containing endless glass fiber reinforcement and surface-functionalized carbon nanotubes (CNTs) dispersed in the matrix phase were produced by resin transfer molding (RTM). An efficient surface modification of the nanotubes enhances the compatibility with the matrix system and the dispersion quality, enabling the impregnation process via liquid composite molding. We assessed the quality of the RTM process by newly developed methodologies for the quantification of the filtering of CNTs. First, we established a method to analyze the CNT length distribution before and after injection for thermosetting composites to characterize length-dependent withholding respectively the size distribution of nanotubes in the hybrid composites. Second, the resulting test laminates were locally examined by Raman spectroscopy and compared to reference (nanocomposite) samples of known CNT content to non-destructively quantify the local CNT concentration along the resin flow path. Moreover, the thermal and mechanical properties of the modified composites were investigated. The nanocomposites containing 0.5 wt% surfacefunctionalized CNTs exhibited superior ductility and increased fracture toughness. Glass fiber hybrid composites containing 0.5 wt% functionalized CNTs in the resin phase exhibited increased fracture toughness in mode I and a slight deterioration in mode II due to the constrained formation of hackles. POLYM. COMPOS.,
The hierarchical structure and properties of multifunctional carbon nanotube fibre composites
Carbon, 2012
The axial mechanical, electrical and thermal properties of carbon nanotubes (CNTs) can be exploited macroscopically by assembling them parallel to each other into a fibre during their synthesis by chemical vapour deposition. Multifunctional composites with high volume fraction of CNT fibres are then made by direct polymer infiltration of an array of aligned fibres. The fibres have a very high surface area, causing the polymer to infiltrate them and resulting in a hierarchical composite structure. The electrical and thermal conductivities of CNT/epoxy composites are shown to be superior to those of equivalent specimens with T300 carbon fibre (CF) which is widely used in industry. From measurements of longitudinal coefficient of thermal expansion (CTE) of the composites we show that the CTE of CNT fibres is approximately À1.6 • 10 À6 K À1 , similar to in-plane graphite. The combination of electrical, thermal and mechanical properties of CNT fibre composites demonstrates their potential for multifunctionality.
Polymer, 1999
To avoid electrostatic charging of an insulating matrix an electrical conductivity above s 10 Ϫ6 Sm Ϫ1 is needed. At present, the most common practice to achieve this conductivity is to use a conductive filler such as carbon black. In this work, untreated catalytically-grown carbon nanotubes were dispersed in an epoxy matrix. After curing the epoxy, the electrical properties of the composite were measured in order to relate the filler volume fraction to the electrical conductivity. The intense stirring process used to disperse the carbon nanotubes has made it possible to achieve a matrix conductivity around s 10 Ϫ2 Sm Ϫ1 with filler volume fractions as low as 0.1 vol.%. These figures represent an advance on best conductivity values previously obtained with carbon black in the same epoxy matrix. These low filler fractions ensure that the mechanical properties of the matrix are not compromised.
Effective formulation and processing of nanofilled carbon fiber reinforced composites
RSC Adv., 2015
This work describes a successful approach toward the development of a carbon fiber-reinforced composite based on an optimized nanofilled resin for industrial applications. The epoxy matrix is prepared by mixing a tetrafunctional epoxy precursor with a reactive diluent which allows reduction of the viscosity of the epoxy precursor and facilitation of the dispersion of 0.5% wt multiwall carbon nanotubes. The proper choice of the viscosity value and the infusion technique allow improvement of the electrical properties of the panels. The obtained in-plane electrical conductivity is about 20 kS m À1 , whereas a value of 3.9 S m À1 is achieved for the out of plane value. Such results confirm that the fibers govern the conduction mechanisms in the direction parallel to the fibers, whereas the percolating path created by the effective distribution of carbon nanotubes achieved by resin formulation and adopted processing approach lead to a significant enhancement of the overall electrical performance of the composites.
Carbon nanotubes (CNTs) were integrated in glass fibres epoxy composites by either including CNTs in the fibre sizing formulation, in the matrix, or both. The effects of such controlled placement of CNTs on the thermophysical properties (glass transition temperature and coefficient of thermal expansion) and the Mode I interlaminar fracture toughness of the composites were studied. The present method of CNT-sizing of the glass fibres produces an increase of almost +10% in the glass transition temperature and a significant reduction of À31% in the coefficient of thermal expansion of the composites. Additionally, the presence of CNTs in the sizing resulted in an increased resistance of crack initiation fracture toughness by +10%, but a lowered crack propagation toughness of À53%. Similar trends were observed for both instances when CNTs were introduced only in the matrix and in combination of both matrix and sizing.
Fibers
An electrophoretic deposition (EPD) prototype was developed aiming at the continuous production of carbon nanotube (CNT) deposited carbon fiber fabric. Such multi-scale reinforcement was used to manufacture carbon fiber-reinforced polymer (CFRP) composites. The overall objective was to improve the mechanical performance and functionalities of CFRP composites. In the current study, the design concept and practical limit of the continuous EPD prototype, as well as the flexural strength and interlaminar shear strength, were the focus. Initial mechanical tests showed that the flexural stiffness and strength of composites with the developed reinforcement were significantly reduced with respect to the composites with pristine reinforcement. However, optical microscopy study revealed that geometrical imperfections, such as waviness and misalignment, had been introduced into the reinforcement fibers and/or bundles when being pulled through the EPD bath, collected on a roll, and dried. These...
Polymer, 2006
Nanostructured modification of polymers has opened up new perspectives for multi-functional materials. In particular, carbon nanotubes (CNTs) have the potential to realise electrically conductive polymers with improved or retaining mechanical performance. This study focuses on the evaluation of both, the electrical and thermal conductivity of nanoparticulate filled epoxy resins. We discuss the results with regard to the influence of the type of carbon nanotube (SWCNT, DWCNT and MWCNT), the relevance of surface-functionalisation (amino-functionalisation), the influence of filler content (wt% and vol%), the varying dispersibility, the aspect ratio and the specific surface area.
Multi-Functional Carbon Fibre Composites using Carbon Nanotubes as an Alternative to Polymer Sizing
Scientific Reports, 2016
Carbon fibre reinforced polymers (CFRP) were introduced to the aerospace, automobile and civil engineering industries for their high strength and low weight. A key feature of CFRP is the polymer sizing-a coating applied to the surface of the carbon fibres to assist handling, improve the interfacial adhesion between fibre and polymer matrix and allow this matrix to wet-out the carbon fibres. In this paper, we introduce an alternative material to the polymer sizing, namely carbon nanotubes (CNTs) on the carbon fibres, which in addition imparts electrical and thermal functionality. High quality CNTs are grown at a high density as a result of a 35 nm aluminium interlayer which has previously been shown to minimise diffusion of the catalyst in the carbon fibre substrate. A CNT modified-CFRP show 300%, 450% and 230% improvements in the electrical conductivity on the 'surface', 'through-thickness' and 'volume' directions, respectively. Furthermore, through-thickness thermal conductivity calculations reveal a 107% increase. These improvements suggest the potential of a direct replacement for lightning strike solutions and to enhance the efficiency of current de-icing solutions employed in the aerospace industry.
Journal of Composite Materials, 2012
Damping characteristics of carbon nanotubes dispersed woven carbon fiber/epoxy composites were investigated. The composites were fabricated by an advanced resin film infusion prepreg manufacturing process based on the calendaring process using three-roll mill. Through this advanced process, well-dispersed nanocomposites containing high weight percent (up to 7 wt%) of carbon nanotubes was achieved. It was confirmed through the scanning electron microscopic images of the carbon nanotubes dispersed composites. Damping characteristics of the specimen were measured by the impact vibration test of the composites beam specimens. Considerable improvement of damping characteristics was observed in the carbon nanotubes dispersed composites, and structural damping increased as the weight percent of carbon nanotubes was increased. Damping ratio was improved up to 12.3% (at the 1st natural frequency) and 16.1% (at the 2nd natural frequency), especially in the 7 wt% carbon nanotubes dispersed spe...