Broad-band electrical conductivity of carbon nanofibre-reinforced polypropylene foams

Antunes, Marcelo; Mudarra, M.; Velasco, José Ignácio

doi:10.1016/j.carbon.2010.10.032

Cited by 100 publications

(80 citation statements)

References 49 publications

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“…This is similar to the fluctuation induced tunnelling model, which was shown to take place in carbon nanotube filled polymers as a result of variations in nanotube-nanotube energy barriers due to local temperature fluctuations [38]. Although dispersion of graphene particles was shown to improve during cell growth, graphene particles trapped within the cell walls should also be pushed closer to each other as the cell walls get smaller during cell growth [14,41], the composite foam conductivities did not improve drastically compared to neat PC and solid composite PC 05GnP. At low frequencies, sample PC 05GnP1 showed the greatest electrical conductivity (  = 9 x10 -13 S/cm) and critical frequency ( c ≈1 Hz).…”

Section: Electrical Conductivitysupporting

confidence: 72%

“…For instance, it has been reported that the foaming process itself can promote ordering of polymer chains [12][13], which could then promote the orientation of nanoparticles. It has been shown that the creation of a cellular structure in composite materials (by means of a foaming process) enhanced electrical conductivity through a tunnelling-like mechanism because of reduced distance between fillers [14]. It has also been stated that the enhancement of electrical conductivity of materials leads to 3 improved electromagnetic interference shielding [15][16][17][18], however, alignment of conductive fillers could have an adverse effect on electromagnetic interference shielding [19].…”

Section: Introductionmentioning

confidence: 99%

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Enhanced electromagnetic interference shielding effectiveness of polycarbonate/graphene nanocomposites foamed via 1-step supercritical carbon dioxide process

et al. 2016

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Abstract:The dielectric and electromagnetic interference (EMI) shielding properties of polycarbonate/graphene nanocomposites foamed using supercritical carbon dioxide were studied as a function of their cellular and composite morphology. Foamed polycarbonate filled with 0.5% (by weight) graphene exhibited enhanced EMI shielding effectiveness, which was found to depend on cellular and composite morphology in a complex manner.Foamed composites presented a maximum specific EMI shielding effectiveness of ~39 dB.cm 3 /g, which is approximately 35 times greater than that of unfoamed composite (1.1 dB.cm 3 /g). In addition, the relative permittivity was found to increase up to 3.25 times. The results suggest that graphene filled polymer foams can enhance the performance of electronic devices, opening up the possibility of using these materials in electronic applications.

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Section: Electrical Conductivitysupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Enhanced electromagnetic interference shielding effectiveness of polycarbonate/graphene nanocomposites foamed via 1-step supercritical carbon dioxide process

et al. 2016

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“…The demand of new lightweight materials with improved transport properties for applications in electrostatic discharge, fuel system components, and electromagnetic interference shielding [29,30]. In their study, they emphasized the importance of particle alignment during cell generation and the importance of this on thermal conductivity of the PP.…”

Section: Polypropylene-based Foamsmentioning

confidence: 99%

“…This indicates the importance of cell morphology on the electrical properties of the polymer foams. An accurately developed cellular structure may help to develop foams for semi-conducting lightweight materials [29][30][31].…”

Section: Polypropylene-based Foamsmentioning

confidence: 99%

Thermoplastic Foams: Processing, Manufacturing, and Characterization

Altan¹

2018

Recent Research in Polymerization

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Polymer foams have wide application area due to their light weight, resistance to impact, high thermal insulation, and damping properties. Automotive, packing industry, electronic, aerospace, building construction, bedding, and medical applications are some of the ields that polymer foams have been used. However, depending on their cell structure-open or closed cell-polymer foams have diferent properties and diferent application areas. In this work, the most used thermoplastic foams with closed cells such as polypropylene, polyethylene, and polystyrene or polylactic acid have been focused. Their melt strength, degree of crystallinity for semi-crystalline ones, and viscosity have great importance on cell morphology. Cells in small diameter with high dense in polymer matrix are preferable. However, obtaining ine cells is not easy in each case, and it is still under investigation for some polymers. There are several ways to improve cell morphology, and one of them is addition of nanoparticle to the polymer. During foaming process, nanoparticles behave like nucleating agent that cells nucleate at the boundary between polymer and the nanoparticle. Besides, foaming agents contribute the homogenous dispersion of the nanoparticles in the polymer matrix, and this improves the properties of the polymer foams and generates multifunctional material as polymer nanocomposite foams.

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“…Electrical conductivity of nano-composite foams is much less studied. Works on the electrical properties of nanoreinforced polymeric foams are rather sporadic [3][4][5][6][7][8][9][10]. The relationship between the resulting electrical conductivity and the density of the rigid foams for given CNT concentrations was reported in [6] but only recently described further [10].…”

mentioning

confidence: 99%

Sensing strain and damage in polyurethane/MWCNT nano-composite foams using electrical measurements

Baltopoulos¹,

Αθανασόπουλος²,

Fotiou³

et al. 2013

Express Polym. Lett.

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The addition of carbon nano-fillers (nanofibers (CNF), nanotubes (CNT) etc.) into plastics has been shown to affect the various properties of the resulting material and effectively increase the electrical conductivity of the system by several orders of magnitude [1]. This is attributed to the formation of a conductive network of the conductive nanofillers, which can be described as a percolated network. The increased electrical conductivity of the nano-reinforced materials has given rise to their use in various applications [2]. Polymeric foams (e.g. Rigid PolyUrethane (PUR)) represent a very interesting and useful sub-group, finding vast range of applications due to their versatility. In structural applications, they are commonly used due to the weight saving capabilities they can offer in the design (e.g. as sandwich cores). Combining nano-fillers with foam materials, nanoreinforcement of foams has been developed and studied the past decade, but mainly focused on the mechanical and thermal properties. Electrical conductivity of nano-composite foams is much less studied. Works on the electrical properties of nanoreinforced polymeric foams are rather sporadic [3][4][5][6][7][8][9][10]. The relationship between the resulting electrical conductivity and the density of the rigid foams for given CNT concentrations was reported in [6] but only recently described further [10]. 40Sensing strain and damage in polyurethane-MWCNT nano-composite foams using electrical measurements A. Baltopoulos, N. Athanasopoulos, I. Fotiou, A. Vavouliotis Abstract. This work deals with the damage identification in polymeric foams through the monitoring of the electrical resistance of the system. To assess this idea electrically conductive rigid Poly-Urethane (PUR) foams at various densities were prepared. Multi-Wall Carbon Nanotubes (MWCNT) were dispersed in the host polymer at various concentrations through high shear mixing to provide electrical conductivity to the system. The PUR/MWCNT foams exhibited varying electrical conductivity on a wide range of densities and nano-filler contents. The prepared foams were subject to compression tests. Electrical resistance was recorded online during the tests to monitor the change of the bulk property of the materials. A structural-electrical cross-property relation was exhibited. The distinctive phases of foam compression were successfully identified from the electrical resistance profile recorded during the tests. A characteristic master curve of the change of electrical resistivity with respect to load and damage is proposed and analyzed. It was shown that the found electrical resistance profile is a characteristic of all the MWCNT contents and depends on density and conductivity. MWCNT content contributes mainly to the sensitivity of electrical sensing in the initial stage of compression. Later compression stages are dominated by foam microstructural damage which mask any effect of CNT dispersion. Micro-structural observations were employed to verify the experimental findings and curves.Keywo...

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Broad-band electrical conductivity of carbon nanofibre-reinforced polypropylene foams

Cited by 100 publications

References 49 publications

Enhanced electromagnetic interference shielding effectiveness of polycarbonate/graphene nanocomposites foamed via 1-step supercritical carbon dioxide process

Enhanced electromagnetic interference shielding effectiveness of polycarbonate/graphene nanocomposites foamed via 1-step supercritical carbon dioxide process

Thermoplastic Foams: Processing, Manufacturing, and Characterization

Sensing strain and damage in polyurethane/MWCNT nano-composite foams using electrical measurements

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