Rheological properties and dispersion of multi-walled carbon nanotube (MWCNT) in polystyrene matrix

Park, Su-Dong; Han, Dong-Hee; Teng, Dayong; Kwon, Yong Hoon

doi:10.1016/j.cap.2007.10.062

Cited by 29 publications

(11 citation statements)

References 5 publications

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“…Although higher moduli are observed for the nanocomposite than for neat polyamide, the response is similar, since in both cases the viscous modulus, G ″, prevails over the elastic modulus, G ′, even at the lowest frequency investigated. The results differ from nanocomposites in which the rheological percolation is noted at low frequencies by an alteration of the terminal viscoelastic zone. This modification of the terminal or flow region owes to the formation of a polymer/nanoparticle combined network (nanoparticle‐polymer‐nanoparticle bridging), that brings about a leveling off of G ′ as frequency tends to zero, in addition to an elastic prevailing response, G ′ > G ″.…”

Section: Resultscontrasting

confidence: 88%

Rheological methods to investigate graphene/amorphous polyamide nanocomposites: Aspect ratio, processing, and crystallization

Canales

Fernández

Peña

et al. 2014

Polymer Engineering & Sci

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Nanocomposites obtained by melt mixing commercial graphene in an amorphous polyamide are investigated. No symptoms of percolation are observed, which is attributed to the low aspect ratio (fs = 20) deduced from elastic modulus data. The study of the effect of temperature and pressure on viscosity, carried out combining extrusion rheometry and PVT tests, reveals that the nanocomposites can be extruded and injected under similar conditions to pure polyamide. The time evolution of the dynamic viscoelastic functions are analyzed to investigate the crystallization process, observing that it is considerably accelerated in nanocomposites. The results represent a valuable outcome for practical applications. POLYM. ENG. SCI., 55:1142–1151, 2015. © 2014 Society of Plastics Engineers

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Section: Resultscontrasting

confidence: 88%

Rheological methods to investigate graphene/amorphous polyamide nanocomposites: Aspect ratio, processing, and crystallization

Canales

Fernández

Peña

et al. 2014

Polymer Engineering & Sci

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“…5, it is seen that the Han plots are close to the G ′ = G ″ line but none of these crosses this line. Getting close and crossing the G ′ = G ″ line implies an increased elastic behavior [1, 18, 25]. According to van Gurp‐Palmen plots presented in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…However, because of their high surface energy they easily tend to agglomerate or entangle, and therefore their dispersion within polymeric matrices remains a challenging task. To overcome this limitation, various approaches have been proposed such as using different dispersing agents [1], in situ polymerization [2], using polymer/CNTs master batches [3, 4] and functionalization of CNTs with different functional groups [5–15]. Among these, the functionalization approach has been widely used due to high efficiency and commercial availability [13–15].…”

Section: Introductionmentioning

confidence: 99%

Effect of sulfur oxyanions on lignocellulose‐derived fermentation inhibitors

Cavka

Alriksson²,

Ahnlund

et al. 2011

Biotech & Bioengineering

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Recent results show that treatments with reducing agents, including the sulfur oxyanions dithionite and hydrogen sulfite, efficiently improve the fermentability of inhibitory lignocellulose hydrolysates, and that the treatments are effective when the reducing agents are added in situ into the fermentation vessel at low temperature. In the present investigation, dithionite was added to medium with model inhibitors (coniferyl aldehyde, furfural, 5-hydroxymethylfurfural, or acetic acid) and the effects on the fermentability with yeast were studied. Addition of 10 mM dithionite to medium containing 2.5 mM coniferyl aldehyde resulted in a nine-fold increase in the glucose consumption rate and a three-fold increase in the ethanol yield. To investigate the mechanism behind the positive effects of adding sulfur oxyanions, mixtures containing 2.5 mM of a model inhibitor (an aromatic compound, a furan aldehyde, or an aliphatic acid) and 15 mM dithionite or hydrogen sulfite were analyzed using mass spectrometry (MS). The results of the analyses, which were performed by using UHPLC-ESI-TOF-MS and UHPLC-LTQ/Orbitrap-MS/MS, indicate that the positive effects of sulfur oxyanions are primarily due to their capability to react with and sulfonate inhibitory aromatic compounds and furan aldehydes at low temperature and slightly acidic pH (such as 25°C and pH 5.5).

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“…Moreover, a good knowledge of the relationship between processing conditions and properties of the nanocomposites is crucial. Most of the reported literature on nanotubes filled polymers has focussed on the quantitative [9] or qualitative [10] description of the dispersion state of nanotubes, the improvement of nanotube dispersion by polymer [11] or nanotubes [12] modifications and/or proper selection of processing parameters (e.g. extrusion rotation speed and screw design [13], shear stress [14]), also on structure [15], viscoelastic (both in solid [16] and molten [17] state), electrical (conductivity [18], resistivity [19], percolation threshold [20]), mechanical (at room [21] and high [22] temperature) or interfacial [23] properties, as well as gas permeability and thermal stability [24] of the CNT filled polymers nanocomposites.…”

Section: Introductionmentioning

confidence: 99%

Taguchi analysis of shrinkage and warpage of injection-moulded polypropylene/multiwall carbon nanotubes nanocomposites

Prashantha¹,

Soulestin²,

Lacrampe³

et al. 2009

Express Polym. Lett.

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Abstract. This paper focuses on the effect of multi-walled carbon nanotube (MWNT) addition on shrinkage and warpage properties of polypropylene (PP) injection mouldings before and after annealing. A Taguchi design of experiments has been implemented to highlight the influence and optimise processing conditions such as injection flow rate, holding pressure, back pressure and screw speed. The addition of 2 wt% of carbon nanotubes into PP significantly reduces the shrinkage and warpage of injection-moulded parts as compared to the neat PP. Skrinkage reduction up to 48% (respectively 33%) is noticed in the flow direction before (respectively after) annealing, whereas warpage reduction exceeds 55%. The sensitivity of the injection-mouldings dimensional properties to processing parameters remains roughly the same in case of neat PP and PP/MWNT nanocomposites when shrinkage is considered. It is even significantly reduced by carbon nanotubes addition when warpage is considered. Furthermore, the Taguchi method provides an efficient and effective tool to study the effects of process parameters on the warpage and shrinkage of injection moulded parts. The additive model used works well for predicting the warpage and shrinkage behaviour of PP and PP/MWNT composites.

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Rheological properties and dispersion of multi-walled carbon nanotube (MWCNT) in polystyrene matrix

Cited by 29 publications

References 5 publications

Rheological methods to investigate graphene/amorphous polyamide nanocomposites: Aspect ratio, processing, and crystallization

Rheological methods to investigate graphene/amorphous polyamide nanocomposites: Aspect ratio, processing, and crystallization

Effect of sulfur oxyanions on lignocellulose‐derived fermentation inhibitors

Taguchi analysis of shrinkage and warpage of injection-moulded polypropylene/multiwall carbon nanotubes nanocomposites

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