Designs of conductive polymer composites with exceptional reproducibility of positive temperature coefficient effect: A review

Pristine carbon nanotubes (CNTs) and functionalized carbon nanotubes (f-CNTs) were introduced into conductive poly(methyl methacrylate)/graphene nanoplatelet (PMMA/GNP) composites to achieve a synergistic effect in the enhancement of the conductivity and the reduction in the percolation threshold by forming a 3-Dimensional(3-D) hybrid structure. Both the in-plane and perpendicular electrical properties were investigated. The synergies of hybrid fillers in the in-plane direction were more dependent on the total filler loading, while those in the perpendicular direction were significantly influenced by the GNP/CNT or GNP/f-CNT ratios. Typically, a schematic diagram of the evolution of the 3-D conductive pathways of PMMA/GNP/f-CNT composite at different GNP/f-CNT ratios was presented to explain this phenomenon. Moreover, tunable conductivity anisotropy (defined as the ratio of in-plane conductivity to perpendicular conductivity) ranging from 0.01 to 1000 was achieved, simply by constructing different conductive structures at various filler loadings or ratios in composites. Graphical abstract The synergistic effect of GNPs and f-CNTs varies with the microstructural conductive network evolution at different filler ratios.

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“…This indicates that the large aggregates and poor distribution of CNTs in Fig. 2 facilitated the formation of conductive networks [59].…”

Section: Electrical Properties Of the Binary Composite Filmsmentioning

confidence: 94%

Electrically conductive polymer composite containing hybrid graphene nanoplatelets and carbon nanotubes: synergistic effect and tunable conductivity anisotropy

Luo¹,

Yang

Schubert

2021

Adv Compos Hybrid Mater

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“…The PTC switching temperature typically corresponds to the melting temperature of the polymer [39]. The melting temperature of POE is about 61.1 °C and HDPE is about 126.1 °C as seen in Figure 4.…”

Section: Electrical Properties Of Hdpe/cb and Hdpe/poe/cbmentioning

confidence: 99%

Effects of POE and Carbon Black on the PTC Performance and Flexibility of High-Density Polyethylene Composites

Xue

Cai

et al. 2021

Advances in Polymer Technology

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High-density polyethylene (HDPE)/carbon black (CB) is widely used in positive temperature coefficient (PTC) composites. In order to expand its applications to fields that need good flexibility, polyolefin elastomer (POE) was incorporated into HDPE/CB composites as a secondary thermoplastic elastomer phase to provide flexibility. The effects of POE and CB content on the PTC performance and flexibility were investigated. Micro morphology and crystallization behavior are closely related to PTC properties. SEM was conducted to reveal phase morphology and filler dispersion, and DSC was conducted to research crystallization behavior. The results show that the incorporation of 18 wt.% POE can decrease the percolation threshold of conductive carbon black from 22.5 wt.% to 16 wt.%. When the CB content is 30 wt.%, the room temperature resistivity gradually increases with the increasing content of POE because of the barrier effect of POE phase, and the PTC intensity is gradually enhanced. Meanwhile, the PTC switching temperature shifts down to a lower temperature. The incorporation of 18 wt.% POE significantly increases the elongation at break, reaching an ultrahigh value of 980 wt.%, which means great flexibility has been achieved in HDPE/POE/CB composites. This work provides a new method of fabricating PTC composites with balanced electrical and mechanical properties.

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“…In particular, the resistivity increased exponentially from 0.47 to 0.90 Ω•cm between −15 and 50 • C. The increase in resistance of PLA/CB might be due to the increased gap between adjacent CB particles dispersed in the composite as the PLA matrix expands with increasing temperature. The increased gap not only leads to breakage of the conducting chains [30], but also interferes with the electron tunneling through the gap [31][32][33]. These causes resulted in the elimination of electrically conductive paths with a consequent increase in the resistivity.…”

Section: Temperature-dependent Resistivity Change Of the 3d Printed Smentioning

confidence: 99%

Resistance Temperature Detectors Fabricated via Dual Fused Deposition Modeling of Polylactic Acid and Polylactic Acid/Carbon Black Composites

Jeon

Hong

Park

et al. 2021

Sensors

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Planar-type resistance temperature detectors (P-RTDs) were fabricated via fused deposition modeling by dual nozzle extrusion. The temperature-sensing element of the fabricated sensor was printed with electrically conductive polylactic acid/carbon black (PLA/CB) composite, while the structural support was printed with a PLA insulator. The temperature-dependent resistivity change of PLA/CB was evaluated for different stacking sequences of PLA/CB layers printed with [0°/0°], [−45°/45°], and [0°/90°] plies. Compared to a PLA/CB filament used as 3D printing source material, the laminated structures exhibited a response over 3 times higher, showing a resistivity change from −10 to 40 Ω∙cm between −15 and 50 °C. Then, using the [0°/90°] plies stacking sequence, a P-RTD thermometer was fabricated in conjunction with a Wheatstone bridge circuit for temperature readouts. The P-RTD yielded a temperature coefficient of resistance of 6.62 %/°C with high stability over repeated cycles. Fabrication scalability was demonstrated by realizing a 3 × 3 array of P-RTDs, allowing the temperature profile detection of the surface in contact with heat sources.

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Designs of conductive polymer composites with exceptional reproducibility of positive temperature coefficient effect: A review

Cited by 37 publications

References 128 publications

Electrically conductive polymer composite containing hybrid graphene nanoplatelets and carbon nanotubes: synergistic effect and tunable conductivity anisotropy

Electrically conductive polymer composite containing hybrid graphene nanoplatelets and carbon nanotubes: synergistic effect and tunable conductivity anisotropy

Effects of POE and Carbon Black on the PTC Performance and Flexibility of High-Density Polyethylene Composites

Resistance Temperature Detectors Fabricated via Dual Fused Deposition Modeling of Polylactic Acid and Polylactic Acid/Carbon Black Composites

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