Dispersion of carbon nanotubes in ultrahigh‐molecular‐weight polyethylene by melt mixing dominated by elongation stress

Yin, Xianze; Yang, Li; He, Guangjian; Feng, Yi; Wen, Jinyu

doi:10.1002/pi.5553

Cited by 14 publications

(4 citation statements)

References 30 publications

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“…For the electrical performance of all nanocomposites, it is not difficult to understand why the conductivity of the ISBS x% nanocomposites has a similar inverted S‐shaped trend as the OBSH loading further increases. Overall, extensive research about the elongation rheology suggests that the dynamic elongation deformation field is more effective at the dispersion of nanoparticles in a short thermal‐mechanical history than shear flow field . Owing to the convergent and divergent flow in the vane mixer, the bubbles are endowed with the special capacity of repeated compression and expansion.…”

Section: Resultsmentioning

confidence: 99%

Homogeneous dispersion of multiwalled carbon nanotubes via in situ bubble stretching and synergistic cyclic volume stretching for conductive LDPE/MWCNTs nanocomposites

Yang

Tong

et al. 2019

Polymer Engineering & Sci

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Low-density polyethylene (LDPE)/multiwalled carbon nanotubes (MWCNTs) nanocomposites with different foaming agent (OBSH) contents were innovatively prepared via In Situ Bubble Stretching (ISBS) and synergistic cyclic volume stretching. The cyclic convergent and divergent flow makes the MWCNTs repeatedly subjected to bubble stretching, which is conducive to the efficient dispersion of MWCNTs in the matrix. The thermal weight loss of neat OBSH and nanocomposite were characterized by thermal gravimetric analyzer (TGA), which indicated that the OBSH in the nanocomposite had been completely decomposed into gas during the plasticizing transport process. The results of morphology showed that the moderate content of OBSH had better dispersion effect on MWCNTs. At optimal OBSH content, the OBSH could generate enough gas and larger bubbles per unit time to provide greater expansion forces to do much for the dispersion of MWCNTs. The dynamic mechanical analysis (DMA) was further carried out and also proved that the content of OSBH was an important factor for the dispersion of MWCNTs. Moreover, the relationship between the OBSH content and conductivity was discussed in details. The improvement in conductive properties of nanocomposites associated with the use of the method can be attributed to a more homogeneous dispersion of MWCNTs. POLYM. ENG.

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Section: Resultsmentioning

confidence: 99%

Homogeneous dispersion of multiwalled carbon nanotubes via in situ bubble stretching and synergistic cyclic volume stretching for conductive LDPE/MWCNTs nanocomposites

Yang

Tong

et al. 2019

Polymer Engineering & Sci

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“…The second step involves the melt blending of nanocomposites compound. The dried HDPE pellets were premixed with the wetted EG in a predetermined proportion and added successively to a vane mixer and mixed at 30 rpm . The evaporation of free water can be effectively prevented due to the porous structure of EG and the positive displacement transport properties of the vane mixer.…”

Section: Methodsmentioning

confidence: 99%

“…The dried HDPE pellets were premixed with the wetted EG in a predetermined proportion and added successively to a vane mixer and mixed at 30 rpm. 21 The evaporation of free water can be effectively prevented due to the porous structure of EG and the positive displacement transport properties of the vane mixer. The processing temperature of the feeding unit was set to 160 °C, and the mixing unit was set to different temperatures and mixing times.…”

Section: Sample Preparationmentioning

confidence: 99%

Cost-Effective Fabrication of High-Density Polyethylene/Graphene Nanocomposites by an In Situ Exfoliation Method Based on a Series Explosion Effect

Zhong

Xie³

et al. 2022

Ind. Eng. Chem. Res.

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As ideal nanofillers, graphene nanosheets (GNS) are widely used to prepare high-performance graphene-reinforced nanocomposites owing to their excellent properties. However, the high manufacturing cost and low production efficiency of GNS severely restrict their large-scale application. Herein, a cost-effective melt blending approach was demonstrated for facilely preparing high-density polyethylene (HDPE)/GNS nanocomposites by using industrial-grade expanded graphite (EG). The exfoliation and dispersion of GNS in the matrix under different processing temperatures and times have been studied. A series explosion effect generated by the synergy of volumetric extensional rheology and free water can violently and fastly exfoliate pristine EG into few-layer GNS. The in situ exfoliation mechanism revealed that the synergistic effect of the explosive forces of free water and the adhesion between HDPE and GNS can destroy the van der Waals forces between the EG sheets during melt blending, thereby realizing ultrafast exfoliation and uniform dispersion of EG in the HDPE matrix. As expected, the HDPE/GNS nanocomposites showed high crystallinity, excellent thermal conductivity, high dielectric constant, and extremely low dielectric loss. This work provides a new idea for facilely fabricating high-performance polymer-based two-dimensional layered nanocomposites.

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“…To generate extensional flow inside a single extruder, Rauwendaal [ 11 ] developed a unique screw design with tapered slots in slanted flights of screws to generate bidirectional elongational flow. Xiaochun et al [ 12 ] successfully dispersed CNTs using a vane extruder, which allowed them to generate elongational flow in a circumferential direction by eccentric rotation of the rotor. Specifically, for the TSE, Carson et al [ 13 ] developed the static extensional mixing element (EME) with multiple hyperbolic contractions as a C‐D channel for generating a uniform extension rate inside the barrel of the TSE.…”

Section: Introductionmentioning

confidence: 99%

A modified blister mixing element for generating extensional flow in a twin‐screw extruder: Process characterization and dispersion state of carbon nanotubes in cyclo‐olefin polymer

Matsumoto

Tanaka

2022

Polymer Engineering & Sci

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This study aimed to improve the dispersion state of single-walled carbon nanotubes (SWCNTs) in a cyclo-olefin polymer (COP) matrix by introducing extensional flow during the compounding through a twin-screw extruder (TSE). A modified mixing element with multiple holes, called a fixed blister disc (XBD), was developed. To describe the mixing performance of XBD, the flow state was characterized via numerical simulation and acquisition of process data such as pressure drop (ΔP) at XBD and specific mechanical energy (SME), while the operational conditions of TSE were varied. The dispersion state of SWCNTs was evaluated from the viewpoint of the melt viscoelastic property, surface resistivity of extruded samples and mechanical properties of injection molded samples. Furthermore, the dispersion morphology was observed via optical microscopy and scanning electron microscopy. As a result, the mixing performance of XBD was improved by increasing the ratio of throughputs Q to screw speed N s (Q/N s ) since ΔP, which is related to extensional stress, was increased. However, the trade-off relationship between ΔP and SME was confirmed versus Q/N s . Although the dispersion state at the submicron level was markedly improved with higher SME inputs, higher ΔP reduced the largest agglomerate size and improved dispersion uniformity. Consequently, the mechanical properties were improved significantly.

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Dispersion of carbon nanotubes in ultrahigh‐molecular‐weight polyethylene by melt mixing dominated by elongation stress

Cited by 14 publications

References 30 publications

Homogeneous dispersion of multiwalled carbon nanotubes via in situ bubble stretching and synergistic cyclic volume stretching for conductive LDPE/MWCNTs nanocomposites

Homogeneous dispersion of multiwalled carbon nanotubes via in situ bubble stretching and synergistic cyclic volume stretching for conductive LDPE/MWCNTs nanocomposites

Cost-Effective Fabrication of High-Density Polyethylene/Graphene Nanocomposites by an In Situ Exfoliation Method Based on a Series Explosion Effect

A modified blister mixing element for generating extensional flow in a twin‐screw extruder: Process characterization and dispersion state of carbon nanotubes in cyclo‐olefin polymer

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