Mechanical properties of a carbon fabric-reinforced epoxy composite with carbon nanotubes and a flame retardant

2016 ◽  
Vol 7 (5) ◽  
pp. 630-644 ◽  
Author(s):  
Martin Kadlec ◽  
Robin Hron ◽  
Liberata Guadagno

Purpose The purpose of this paper is to present the mechanical and morphological characterization of new multifunctional carbon fibre-reinforced composites (CFRCs) that are able to overcome two of the main drawbacks of aeronautical composite materials: reduced electrical conductivity and poor flame resistance. Multiwall carbon nanotubes and glycidyl POSS (GPOSS) were used to simultaneously enhance electrical conductivity and flame resistance. The effect of these two combined components on the mechanical and morphological properties of the manufactured CFRCs was analysed. Design/methodology/approach This paper describes the mechanical test results obtained for interlaminar shear strength, three-point bending, and tensile and fracture toughness in mode I tests. Carbon fibre-reinforced epoxy resin plates were manufactured in two series with blank resin and CNT+flame retardant GPOSS-enhanced resin. Findings The mechanical properties were decreased by no more than 10 per cent by combined influence of CNTs and GPOSS. Agglomerates of CNTs were observed using scanning electron microscopy. The agglomerates were large enough to be visible to the naked eye as black spots on the delaminated fracture surface. The decrease of the mechanical properties could be caused by these agglomerates or by a changed fibre volume content that was affected by the difficult infusion procedure due to high resin viscosity. Originality/value If we consider the benefit of CNTs as a nanofiller to increase electrical conductivity and the GPOSS as a component to increase the flame resistance of the resin, the decrease of strength seems to be insignificant.

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3140
Author(s):  
Kamil Dydek ◽  
Anna Boczkowska ◽  
Rafał Kozera ◽  
Paweł Durałek ◽  
Łukasz Sarniak ◽  
...  

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.


2011 ◽  
Vol 6 (3) ◽  
pp. 155892501100600 ◽  
Author(s):  
Eric Devaux ◽  
Carole Aubry ◽  
Christine Campagne ◽  
Maryline Rochery

Polylactide (PLA) was mixed with 4 wt.% of carbon nanotubes (CNTs) to produce electrical conductive multifilament yarns by melt spinning process for humidity detection. Thanks to a variation of electrical conductivity, this flexible sensor could detect the moisture presence. The introduction of plasticizer was necessary to ensure higher fluidity and drawability of the blend during the spinning process. The plasticizer modifies the crystallinity and the mechanical properties of the yarns. The effectiveness of this sensor (PLA/4 wt.% CNTs fibres) sensitive to humidity, is optimal when the spinning conditions are adapted. In this way, the temperature and the rate of the drawing roll were reduced. The influence of these parameters on the crystallinity, the mechanical properties and the sensitivity of the yarns were studied. Once the appropriate spinning conditions found, one humidity sensitive yarn was processed and the repeatability and efficient reversibility of its sensitivity were highlighted.


2018 ◽  
Vol 24 (8) ◽  
pp. 1337-1346 ◽  
Author(s):  
Marzio Grasso ◽  
Lyes Azzouz ◽  
Paula Ruiz-Hincapie ◽  
Mauro Zarrelli ◽  
Guogang Ren

Purpose Recent advancements of 3D printing technology have brought forward the interest for this technique in many engineering fields. This study aims to focus on mechanical properties of the polylactic acid (PLA) feeding material under different thermal conditions for a typical fusion deposition of 3D printer system. Design/methodology/approach Specimens were tested under static loading within the range 20ºC to 60ºC considering different infill orientations. The combined effect of temperature and filament orientation is investigated in terms of constitutive material parameters and final failure mechanisms. The difference between feeding system before and post-3D printing was also assessed by mechanical test on feeding filament to verify the thermal profile during the deposition phase. Findings The results in terms of Young’s modulus, ultimate tensile strength (UTS), strain at failure (εf) and stress at failure (σf) are presented and discussed to study the influence of process settings over the final deposited material. Fracture surfaces have been investigated using an optical microscope to link the phenomenological interpretation of the failure with the micro-mechanical behaviour. Experimental results show a strong correlation between stiffness and strength with the infill orientation and the temperature values. Moreover, a relevant effect is related to deformed geometry of the filament approaching glass transition region of the polymer according to the deposition orientation. Research limitations/implications The developed method can be applied to optimise the stiffness and strength of any 3D-printed composite according to the infill orientation. Practical implications To avoid the failure of specimens outside the gauge length, a previously proposed modification to the geometry was adopted. The geometry has a parabolic profile with a curvature of 1,000 mm tangent to the middle part of the specimen. Originality/value Several authors have reported the stiffness and strength of 3D-printed parts under static and ambient temperature for different build parameters. However, there is a lack of literature on the combination of the latter with the temperature effects on the mechanical properties which this paper covers.


2019 ◽  
Vol 48 (3) ◽  
pp. 197-201
Author(s):  
Buqin Xu ◽  
Guilong Xu ◽  
Hui Qiao ◽  
Yun Liang ◽  
Jin Yang ◽  
...  

Purpose The flammability of poly-acrylate (PA) resin is a major disadvantage in applications that require flame resistance. It has been reported that a flame-retardant PA resin could be prepared by covalent incorporate phosphorous containing monomer with vinyl group via free radical polymerization, and the prepared modified PA resin is expected to exhibit better flame resistance than those by an additive approach. However, the phosphorus-containing monomers reported previously are made from expensive or toxic materials, and the production procedure is tedious and under harsh reaction conditions, which are not feasible for industrial application. Therefore, the purpose of this paper is the preparation of flame-retardant PA resin modified by epoxy resin phosphorous acid (EPPA) and the study of its flame retardancy. Design/methodology/approach EPPA is first prepared by epoxy resin E-51 and phosphorous acid and then used to prepare phosphorous containing PA resin by free radical polymerization. The flame retardancy of the prepared EPPA-modified PA (EPPA-PA) resin is studied. Findings The results show that EPPA can graft onto the PA polymer chain by free radical polymerization, the flame retardancy of the EPPA-PA resin increases as the EPPA content increasing. The flame retardancy of EPPA-PA resin prepared reaches 27.8% and can pass the V-0 rating in the UL-94 test when EPPA content is 30.0%. SEM and EDS results indicate that phosphorous element in the EPPA-PA resin shows a condensed-phase flame retardant effect. Research limitations/implications The grafting degree of EPPA cannot be accurately tested. Practical implications It is expected that the large-scale production of this epoxy resin phosphoric acid modified PA resin will enable practical industrial applications. Originality/value This method for synthesis of epoxy resin phosphoric acid modified PA resin is newfrangled.


Aerospace ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 120 ◽  
Author(s):  
Barbara Tse ◽  
Xueli Yu ◽  
Hugh Gong ◽  
Constantinos Soutis

Recycling carbon fibre is crucial in the reduction of waste from the increasing use of carbon fibre reinforced composites in industry. The reclaimed fibres, however, are usually short and discontinuous as opposed to the continuous virgin carbon fibre. In this work, short recycled carbon fibres (rCF) were mixed with flax and poly-lactic acid (PLA) fibres acting as the matrix to form nonwoven mats through wet-laying. The mats were compression moulded to produce composites with different ratios of rCF and flax fibre in the PLA matrix. Their flexural behaviour was examined through three-point-bending tests, and their morphological properties were characterised with scanning electron and optical microscopes. Experimental data showed that the flexural properties increased with higher rCF content, with the maximum being a flexural modulus of approximately 14 GPa and flexural strength of 203 MPa with a fibre volume fraction of 75% rCF and 25% flax fibre. The intimate mixing of the fibres contributed to a lesser reduction of flexural properties when increasing the flax fibre content.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Tuan Anh Nguyen

Modern flame retardants are organic compounds containing halogen or phosphorus groups and are not always well dispersed in polymers. Thus, by using a small amount of nanoclay and multiwalled carbon nanotubes (MWCNTs), they can significantly reduce the number of conventional flame retardant additives, making the material with optimal flame retardant properties. Conventional flame retardants always have some negative effects on the mechanical properties of the polymer substrate, so by using nanoclay and MWCNTs, those adverse effects can be minimized and overcome. In this work, in order to improve the mechanical properties and flame retardant of nanocomposite materials, nanoclay I.30E and MWCNTs are mixed into epoxy, with the selected percentage of 2% and 0.02% by weight, respectively, stirring mechanically for 7, 8, and 9 hours at 3000 rpm at 80°C, then performing ultrasonic vibration for 6 hours at 65°C.


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