Thermal and flammability properties of polypropylene/carbon nanotube nanocomposites

Kashiwagi, Takashi; Grulke, Eric A.; Hilding, Jenny; Groth, Katrina M.; Harris, Richard H.; Butler, Kathryn M.; Shields, John R.; Kharchenko, S B.; Douglas, Jack F.

doi:10.1016/j.polymer.2004.03.088

Cited by 603 publications

(421 citation statements)

References 34 publications

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“…The weight of the sample was continuously measured by a sensitive weight device and mass loss rate was calculated by taking the time derivative of the weight. The observed mass loss rate in this device correlates well with heat release rate (a direct measure of the size of a fire) of polymer-CNT nanocomposites [22,36] and polymer-clay nanocomposites [37]. The apparatus consists of a stainless-steel cylindrical chamber that is 1.70 m tall and 0.61 m in diameter.…”

Section: Methodsmentioning

confidence: 80%

“…In attempts to achieve well-dispersed CNTs in a polymer, functionalization of the CNT walls [9,10], use of surfactants [11], controlled duration of sonication of mixtures of CNTs in various solvents [12,13,14,15,16], in situ polymerization under sonication [17], in situ bulk polymerization [18], high speed mechanical stirring [19,20], and compounding using a twin screw extruder [21,22] have been used. The dispersion of the CNTs in the polymer was mainly determined by taking images using transmission electron microscopy (TEM), scanning electron microscopy (SEM), or optical microscopy.…”

Section: Introductionmentioning

confidence: 99%

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Relationship between dispersion metric and properties of PMMA/SWNT nanocomposites

Kashiwagi

Fagan

Douglas

et al. 2007

Polymer

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169

113

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Particle spatial dispersion is a crucial characteristic of polymer composite materials and this property is recognized as especially important in nanocomposite materials due to the general tendency of nanoparticles to aggregate under processing conditions. We introduce dispersion metrics along with a specified dispersion scale over which material homogeneity is measured and consider how the dispersion metrics correlate quantitatively with the variation of basic nanocomposite properties. We then address the general problem of quantifying nanoparticle spatial dispersion in model nanocomposites of single wall carbon nanotubes (SWNT) dispersed in poly(methyl methacrylate) (PMMA) at a fixed SWNT concentration of 0.5 % using a 'coagulation' fabrication method. Two methods are utilized to measure dispersion, UV-Vis spectroscopy and optical confocal microscopy. Quantitative spatial dispersion levels were obtained through image analysis to obtain a 'relative dispersion index' (RDI) representing the uniformity of the dispersion of SWNTs in the samples and through absorbance. We find that the storage modulus, electrical conductivity, and flammability containing the same amount of SWNTs, the relationships between the quantified dispersion levels and physical properties show about four orders of magnitude variation in storage modulus, almost eight orders of magnitude variation in electric conductivity, and about 70 % reduction in peak mass loss rate at the highest dispersion level used in this study. The observation of such a profound effect of SWNT dispersion indicates the need for objective dispersion metrics for correlating and understanding how the properties of nanocomposites are determined by the concentration, shape and size of the nanotubes. conditions. We introduce dispersion metrics along with a specified dispersion scale over which material homogeneity is measured and consider how the dispersion metrics correlate quantitatively with the variation of basic nanocomposite properties. We then address the general problem of quantifying nanoparticle spatial dispersion in model nanocomposites of single wall carbon nanotubes (SWNT) dispersed in poly(methyl methacrylate) (PMMA) at a fixed SWNT concentration of 0.5 % using a 'coagulation' fabrication method. Two methods are utilized to measure dispersion, UV-Vis spectroscopy and optical confocal microscopy. Quantitative spatial dispersion levels were obtained through image analysis to obtain a 'relative dispersion index ' (RDI) representing the uniformity of the dispersion of SWNTs in the samples and through absorbance. We find that the storage modulus, electrical conductivity, and flammability † This was carried out by the National Institute of Standards and Technology (NIST), an agency of the US Government and is not subject to copyright in the US. ‡ Correspondence to: T. Kashiwagi (E-mail: takashi.kashiwagi@nist.gov) 1 property of the nanocomposites correlates well with the RDI. For the nanocomposites containing the same amount of SWNTs, the relationships betw...

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Section: Methodsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Relationship between dispersion metric and properties of PMMA/SWNT nanocomposites

Kashiwagi

Fagan

Douglas

et al. 2007

Polymer

Self Cite

169

113

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“…In literature, usually the employ of carbon nanotubes as flame retardant additives has been well documented. Indeed, their highly elongated shape and thus the high aspect ratio play a crucial factor in the reduction of the flammability of some polymers such as polypropylene [21,22], poly methyl methacrylate [23] and poly ethylene vinyl acetate [24]. Analogously, carbon nanofibers can behave similarly to carbon nanotubes as flame retardants promoting the in situ formation of a continuous network structured protective layer from the tubes.…”

Section: -Combustion Behaviormentioning

confidence: 99%

“…One of the most promising applications involves the improvement in flame retardancy properties of polymers added with nanofillers. The possibility to reduce flammability of numerous polymers using nanoclays have been shown by many authors and several mechanisms are proposed [5][6][7][8][9][10][11][12][13][14][15][16][17]. Indeed, nanocomposite systems are a new attractive alternative to conventional commercial flame retardants.…”

Section: Introductionmentioning

confidence: 99%

“…Nowadays, the most common approach to nanocomposite fire retardants is based on the use of layered silicates characterized by a large aspect ratio. Carbon nanotubes and carbon nanofibers are suitable candidate as flame retardant: Kashiwagi and coworkers [13,14] demonstrated that multi-walled carbon nanotubes can be used for reducing the flammability properties of polypropylene, and that it is possible also to use single walled carbon nanotubes for poly(methyl methacrylate) for the same purpose [15]. These fillers are also used as reinforcement.…”

Section: Introductionmentioning

confidence: 99%

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Poly(ethylene terephthalate)-carbon nanofiber nano composite for fiber spinning; properties and combustion behavior

Alongi¹,

Frache

2010

E-Polymers

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Carbon nanofiber (CNF)-polyethylene terephthalate (PET) blends were previously prepared by melt blending and, subsequently, melt spun in order to obtain nanostructured fibers characterized by high flame retardant properties and resistance to the combustion. The morphological analysis showed that CNFs are homogeneously distributed and finely dispersed within PET matrix. The mechanical properties in tensile testing of the fibers change in the presence of CNFs: the elongation at break increases, whereas the tenacity and the tensile strength decrease. The combustion tests by cone calorimetry reveal a relevant decrease of heat release rate, total heat evolved and total smokes released by the nanocomposites as compared to neat PET.

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Carbon Nanotubes and Nanocomposites for Electrical and Thermal Applications

Wang

Veca

et al. 2005

Encyclopedia of Inorganic Chemistry

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The extraordinary electrical and thermal properties of individual carbon nanotubes have prompted predictions on their potentials for ultimately forming polymeric nanocomposites. A significant barrier for the predicted nanocomposites is the severe bundling and insolubility of carbon nanotubes. Chemical modification and functionalization have been demonstrated as being effective in the debundling and solubilization of carbon nanotubes for their homogeneous dispersion into polymer matrices for desired high‐quality nanocomposites. More elegant is the approach to use polymers that are structurally identical or maximally similar to the matrix polymers in the nanotube functionalization to ensure full compatibility of the functionalized nanotubes with the corresponding polymer matrix. Several representative examples are presented, along with discussion on the benefits and issues concerning the polymeric nanocomposites thus obtained. For superior electrical properties, there is experimental evidence suggesting that the nanotube dispersion in the polymer matrix plays an important role. More promising is the use of separated metallic carbon nanotubes for a much enhanced performance in conductive nanocomposites and in related applications, such as transparent conductive films. For highly thermal conductive polymeric nanocomposites, on the other hand, the feasibility of using carbon nanotubes to achieve the desired performance has yet to be convincingly demonstrated experimentally. Nevertheless, the available results do suggest significant effects of the nanotube dispersion and alignment on thermal conductivities of the nanocomposites.

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Thermal and flammability properties of polypropylene/carbon nanotube nanocomposites

Cited by 603 publications

References 34 publications

Relationship between dispersion metric and properties of PMMA/SWNT nanocomposites

Relationship between dispersion metric and properties of PMMA/SWNT nanocomposites

Poly(ethylene terephthalate)-carbon nanofiber nano composite for fiber spinning; properties and combustion behavior

Carbon Nanotubes and Nanocomposites for Electrical and Thermal Applications

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