Pros and cons of melt annealing on the properties of MWCNT/polypropylene composites

Gentile, Gennaro; Ambrogi, Veronica; Cerruti, Pierfrancesco; Maio, Rosa Di; Nasti, Giuseppe; Carfagna, Cosimo

doi:10.1016/j.polymdegradstab.2014.08.018

Cited by 18 publications

(15 citation statements)

References 47 publications

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“…) showing fewer network forming. This is consistent with some literature findings which observed a lowering of rheological percolation threshold as CNT dispersity increases . At the high shear rate, η * in the 1 wt% nanocomposite became lower than for the neat PP, implying a stronger shear thinning behavior in the presence of both MA‐ g ‐PP and f‐MWNT.…”

Section: Resultssupporting

confidence: 92%

“…Rheology is a powerful tool for probing the molecular level motion and microstructure of the filled polymer systems because the linear viscoelastic response of the nanocomposites are highly dependent on both the filler dispersion and the interaction between fillers and polymers that altered because of other additives such as compatibilizer or filler functionalization . Ma et al reported that the acid treated MWNTs in epoxy resin with good dispersion exhibited lower complex viscosity and G ′ than that with poor dispersion state sample processed using untreated MWNT.…”

Section: Resultsmentioning

confidence: 99%

“…) suggests deviation from terminal behavior ( G ′~ω 2 ), and should be attributed to the formation of polymer‐filler network, rather than filler‐filler network. More specifically, if this is due to CNT–CNT networks, the effect would be stronger in the MA‐ g ‐PP/f‐MWNT‐based sample since better f‐MWNT dispersion facilitates the filler network formation .…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Rheological behavior of polypropylene nanocomposites with tailored polymer/multiwall carbon nanotubes interface

Wang

Gulgunje

Ghoshal

et al. 2019

Polymer Engineering & Sci

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Maleic anhydride grafted polypropylene (MA-g-PP) or polypropylene (PP) was noncovalently coated onto acid functionalized multiwall carbon nanotube (f-MWNT) through solution mixing. These coated f-MWNTs and pristine MWNT (p-MWNT) were melt microcompounded with neat PP to form PP/f-MWNT and PP/p-MWNT nanocomposites at 0.1-1 wt% MWNT concentration. Complex viscosity and tan δ (ratio of loss modulus to storage modulus) behavior of these systems were studied using dynamic frequency sweep test, while relaxation time, activation energy, and melt homogeneity were also calculated and compared. Among the three types of samples, PP/f-MWNT masterbatch-based nanocomposite demonstrated not only the presence of interphase but also good processability. As a consequence, increase of both the crystallization rate in the presence of shear and the melt elasticity during annealing were found only in the masterbatchbased samples but not in the PP/p-MWNT. The mechanism of such increased melt elasticity was attributed to the formation of the space-spanning network, which is consistent with the Cole-Cole plot showing similar behavior to the branched polymers in the literature. This has implications in polymer processing due to suggested changes in the balance between melt strength and polymer flow. Nanocomposite rheological behavior has also been correlated with the mechanical properties.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Rheological behavior of polypropylene nanocomposites with tailored polymer/multiwall carbon nanotubes interface

Wang

Gulgunje

Ghoshal

et al. 2019

Polymer Engineering & Sci

View full text Add to dashboard Cite

show abstract

“…To this aim, it is necessary to counterbalance the attraction energy between particles due to Van der Waals interaction [21][22][23]. For these systems, a concentration percolation threshold is defined that is the critical concentration of nanoparticles that leads to the formation of a continuous network within the material.…”

Section: A N U S C R I P Tmentioning

confidence: 99%

Double percolation of multiwalled carbon nanotubes in polystyrene/polylactic acid blends

Nasti

Gentile

Cerruti

et al. 2016

Polymer

Self Cite

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“…Mutation of the macromolecular architecture can be related to various events, such as changes in molecular weight and molecular weight distribution [22] or in the physical or chemical connectivity between polymer molecules within a gel [23]. Thermally induced phase separation can take place in polymer blends or block copolymers [24], while flocculation of nanoparticles can be experienced in polymer-based composites [25], and gelation phenomena [26] or fast degradation reactions can occur when measurements are performed at high temperatures (melt state) [27].…”

Section: Introductionmentioning

confidence: 99%

Structure Evolution of Epoxidized Natural Rubber (ENR) in the Melt State by Time-Resolved Mechanical Spectroscopy

et al. 2020

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In this work, time-resolved mechanical spectroscopy (TRMS) was used to accurately characterize the rheological behavior of an epoxidized natural rubber (ENR) containing 25 mol% of epoxy groups. Conventional rheological tests are not suitable to characterize with accuracy the frequency-dependent linear viscoelastic behavior of materials, such as ENR, in a transient configurational state. For this reason, TRMS was used to determine the true rheological behavior of ENR, as well as to gain some insights into the changes of its macromolecular architecture under the dynamic conditions experienced during the measurements. The constructed master curves for the moduli revealed a gradual transition of the ENR rheological state from liquid-like to solid-like through the formation of an “elastic gel” throughout the bulk of the polymer. Furthermore, the evolution of the stress relaxation modulus revealed a slow relaxation mechanism, resulting from thermally activated reactions in the molten state attributed to the formation of crosslinks. Finally, the crosslink density evolution was estimated from the TRMS data and compared with results derived from equilibrium solvent-swelling measurements. These demonstrated the accuracy of the TRMS data in the prediction of the structural changes that can take place in polymers during processing.

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Pros and cons of melt annealing on the properties of MWCNT/polypropylene composites

Cited by 18 publications

References 47 publications

Rheological behavior of polypropylene nanocomposites with tailored polymer/multiwall carbon nanotubes interface

Rheological behavior of polypropylene nanocomposites with tailored polymer/multiwall carbon nanotubes interface

Double percolation of multiwalled carbon nanotubes in polystyrene/polylactic acid blends

Structure Evolution of Epoxidized Natural Rubber (ENR) in the Melt State by Time-Resolved Mechanical Spectroscopy

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