scholarly journals Achieving a low electrical percolation threshold and superior mechanical performance in poly(l-lactide)/thermoplastic polyurethane/carbon nanotubes composites via tailoring phase morphology with the aid of stereocomplex crystallites

RSC Advances ◽  
2017 ◽  
Vol 7 (18) ◽  
pp. 11076-11084 ◽  
Author(s):  
Zhenwei Liu ◽  
Hongwei Bai ◽  
Yuanlin Luo ◽  
Qin Zhang ◽  
Qiang Fu
Keyword(s):  
Carbon Nanotubes ◽  
Percolation Threshold ◽  
Mechanical Performance ◽  
Thermoplastic Polyurethane ◽  
Phase Morphology ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

We demonstrate a facile strategy to fabricate highly conductive PLLA/TPU/CNTs composites with very low percolation threshold and good stiffness–toughness balance via constructing stereocomplex crystallites in PLLA melt to tailor phase morphology.

scholarly journals A Numerical Study on Electrical Percolation of Polymer-Matrix Composites with Hybrid Fillers of Carbon Nanotubes and Carbon Black

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yuli Chen ◽  
Shengtao Wang ◽  
Fei Pan ◽  
Jianyu Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Electrical Percolation ◽  
Hybrid Fillers ◽  
Nonlinear Relation ◽  
Electrical Percolation Threshold

The electrical percolation of polymer-matrix composites (PMCs) containing hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.

scholarly journals Melt-Mixed 3D Hierarchical Graphene/Polypropylene Nanocomposites with Low Electrical Percolation Threshold

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1766 ◽  
Author(s):  
Thomas Gkourmpis ◽  
Karolina Gaska ◽  
Davide Tranchida ◽  
Antonis Gitsas ◽  
Christian Müller ◽  
...  
Keyword(s):  
Percolation Threshold ◽  
Mechanical Performance ◽  
Pristine Graphene ◽  
Melt Mixing ◽  
Electrical Percolation ◽  
Β Phase ◽  
Polypropylene Nanocomposites ◽  
Electrical Percolation Threshold ◽  
Filler Dispersion ◽  
Mixed Systems

Graphene-based materials are a family of carbonaceous structures that can be produced using a variety of processes either from graphite or other precursors. These materials are typically a few layered sheets of graphene in the form of platelets and maintain some of the properties of pristine graphene (such as two-dimensional platelet shape, aspect ratio, and graphitic bonding). In this work we present melt mixed graphene-based polypropylene systems with significantly reduced percolation threshold. Traditionally melt-mixed systems suffer from poor dispersion that leads to high electrical percolation values. In contrast in our work, graphene was added into an isotactic polypropylene matrix, achieving an electrical percolation threshold of ~1 wt.%. This indicates that the filler dispersion process has been highly efficient, something that leads to the suppression of the β phase that have a strong influence on the crystallization behavior and subsequent thermal and mechanical performance. The electrical percolation values obtained are comparable with reported solution mixed systems, despite the use of simple melt mixing protocols and the lack of any pre or post-treatment of the final compositions. The latter is of particular importance as the preparation method used in this work is industrially relevant and is readily scalable.

scholarly journals Using an Ionic Liquid to Reduce the Electrical Percolation Threshold in Biobased Thermoplastic Polyurethane/Graphene Nanocomposites

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 435 ◽  
Author(s):  
Nora Aranburu ◽  
Itziar Otaegi ◽  
Gonzalo Guerrica-Echevarria
Keyword(s):  
Ionic Liquid ◽  
Percolation Threshold ◽  
Thermoplastic Polyurethane ◽  
Melt Mixing ◽  
Graphene Nanocomposites ◽  
Electrical Percolation ◽  
Twin Screw ◽  
Electrical Percolation Threshold ◽  
A Minor ◽  
Positive Effect

Biobased thermoplastic polyurethane (bTPU)/unmodified graphene (GR) nanocomposites (NCs) were obtained by melt-mixing in a lab-scaled conventional twin-screw extruder. Alternatively, GR was also modified with an ionic liquid (GR-IL) using a simple preparation method with the aim of improving the dispersion level. XRD diffractograms indicated a minor presence of well-ordered structures in both bTPU/GR and bTPU/GR-IL NCs, which also showed, as observed by TEM, nonuniform dispersion. Electrical conductivity measurements pointed to an improved dispersion level when GR was modified with the IL, because the bTPU/GR-IL NCs showed a significantly lower electrical percolation threshold (1.99 wt%) than the bTPU/GR NCs (3.21 wt%), as well as higher conductivity values. Young’s modulus increased upon the addition of the GR (by 65% with 4 wt%), as did the yield strength, while the ductile nature of the bTPU matrix maintained in all the compositions, with elongation at break values above 200%. This positive effect on the mechanical properties caused by the addition of GR maintained or slightly increased when GR-IL was used, pointing to the success of this method of modifying the nanofiller to obtain bTPU/GR NCs.

scholarly journals Influence of Carbon Nanotube-Pretreatment on the Properties of Polydimethylsiloxane/Carbon Nanotube-Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1355
Author(s):  
Astrid Diekmann ◽  
Marvin C. V. Omelan ◽  
Ulrich Giese
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Mechanical Performance ◽  
Softening Effect ◽  
Electrical Percolation ◽  
Optimum Parameters ◽  
Lauryl Ether ◽  
Solvent Residues ◽  
Electrical Percolation Threshold ◽  
Filler Dispersion

Incorporating nanofillers into elastomers leads to composites with an enormous potential regarding their properties. Unfortunately, nanofillers tend to form agglomerates inhibiting adequate filler dispersion. Therefore, different carbon nanotube (CNT) pretreatment methods were analyzed in this study to enhance the filler dispersion in polydimethylsiloxane (PDMS)/CNT-composites. By pre-dispersing CNTs in solvents an increase in electrical conductivity could be observed within the sequence of tetrahydrofuran (THF) > acetone > chloroform. Optimization of the pre-dispersion step results in an AC conductivity of 3.2 × 10−4 S/cm at 1 Hz and 0.5 wt.% of CNTs and the electrical percolation threshold is decreased to 0.1 wt.% of CNTs. Optimum parameters imply the use of an ultrasonic finger for 60 min in THF. However, solvent residues cause a softening effect deteriorating the mechanical performance of these composites. Concerning the pretreatment of CNTs by physical functionalization, the use of surfactants (sodium dodecylbenzenesulfonate (SDBS) and polyoxyethylene lauryl ether (“Brij35”)) leads to no improvement, neither in electrical conductivity nor in mechanical properties. Chemical functionalization enhances the compatibility of PDMS and CNT but damages the carbon nanotubes due to the oxidation process so that the improvement in conductivity and reinforcement is superimposed by the CNT damage even for mild oxidation conditions.

Electrical conductivity and rheological properties of carbon black based conductive polymer composites prior to and after annealing

2021 ◽  
pp. 096739112110012
Author(s):  
Qingsen Gao ◽  
Jingguang Liu ◽  
Xianhu Liu
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Rheological Properties ◽  
Network Formation ◽  
Loss Modulus ◽  
Conductive Polymer ◽  
Complex Viscosity ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

The effect of annealing on the electrical and rheological properties of polymer (poly (methyl methacrylate) (PMMA) and polystyrene (PS)) composites filled with carbon black (CB) was investigated. For a composite with CB content near the electrical percolation threshold, the formation of conductive pathways during annealing has a significant impact on electrical conductivity, complex viscosity, storage modulus and loss modulus. For the annealed samples, a reduction in the electrical and rheological percolation threshold was observed. Moreover, a simple model is proposed to explain these behaviors. This finding emphasizes the differences in network formation with respect to electrical or rheological properties as both properties belong to different physical origins.

A promising approach to low electrical percolation threshold in PMMA nanocomposites by using MWCNT-PEO predispersions

2016 ◽  
Vol 111 ◽  
pp. 253-262 ◽  
Author(s):  
Seyed Mohammad Mir ◽  
Seyed Hassan Jafari ◽  
Hossein Ali Khonakdar ◽  
Beate Krause ◽  
Petra Pötschke ◽  
...  
Keyword(s):  
Percolation Threshold ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold
Sign in / Sign up

Export Citation Format

Share Document