scholarly journals Supercritical Fluids-Assisted Processing Using CO2 Foaming to Enhance the Dispersion of Nanofillers In Poly(Butylene Succinate)-Based Nanocomposites and the Conductivity

Author(s):  
An Huang ◽  
Xincheng Song ◽  
Fan Liu ◽  
Haokun Wang ◽  
Lihong Geng ◽  
...  

Abstract With the rapid development of electronic information technology, traditional metal conductive materials can no longer satisfy the needs of a wider industry. Poly(butylene succinate)/multiwalled carbon nanotubes (PBS/CNT) conductive polymer nanocomposites with varied CNT content were prepared by a HAAKE torque rheometer. The addition of CNT significantly improved the crystallization, viscoelasticity, and mechanical properties as well as thermal and electrical conductivity. Conductivity of the PBS/CNT nanocomposite with 5 wt.% CNT increased from 8.23×10− 15 S·m− 1 of pure PBS to 33.3 S·m− 1, an increase of 16 orders of magnitude. Moreover, the electrical percolation threshold φc of the PBS/CNT nanocomposites was 2.8 wt.% and the critical index was 1.56, showing that the conductive network structure was between 2D and 3D and 2D network structure dominated. To further improve the conductivity, microcellular foams were successfully fabricated by batch foaming with supercritical fluids (scCO2). The electrical conductivity of the PBS/CNT foam with 5 wt.% CNT reached 67.8 S·m− 1 and it was 104% higher than the corresponding solid nanocomposite.

2021 ◽  
pp. 096739112110012
Author(s):  
Qingsen Gao ◽  
Jingguang Liu ◽  
Xianhu Liu

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Penwisa Pisitsak ◽  
Rathanawan Magaraphan ◽  
Sadhan C. Jana

A thermotropic liquid crystalline polymer (LCP) was blended with polycarbonate (PC) and multiwalled carbon nanotube (CNT) with the goal of improving electrical conductivity and mechanical properties over PC. The LCP was anticipated to produce fibrillar domains in PC and help improve the mechanical properties. The study was carried out using two grades of LCP—Vectra A950 (VA950) and Vectra V400P (V400P). The compounds contained 20 wt% LCP and 0.5 to 15 wt% CNT. The compounds were prepared by melt-blending in a twin-screw minicompounder and then injection molded using a mini-injection molder. The fibrillar domains of LCP were found only in the case of PC/VA950 blend. However, these fibrils turned into droplets in the presence of CNT. It was found that CNT preferentially remained inside the LCP domains as predicted from the value of spreading coefficient. The electrical conductivity showed the following order with the numbers in parenthesis representing the electrical percolation threshold of the compounds: PC/CNT (1%) > PC/VA950P/CNT (1%) > PC/V400P/CNT (3%). The storage modulus showed improvements with the addition of CNT and VA950.


Author(s):  
Xiaolong Gao ◽  
Yao Huang ◽  
Xiaoxiang He ◽  
Xiaojing Fan ◽  
Ying Liu ◽  
...  

Electrically conductive polymer composites are in high demand for modern technologies, however, the intrinsic brittleness of conducting conjugated polymers and the moderate electrical conductivity of engineering polymer/carbon composites have highly constrained their applications. In this work, super high electrical conductive polymer composites were produced by a novel hot embossing design. The polydimethylsiloxane (PDMS) composites containing short carbon fiber (SCF) exhibited an electrical percolation threshold at 0.45 wt%, and reached a saturated electrical conductivity of 49 S/m at 8 wt% of SCF. When reduced the sample thickness from 1.0 mm to 0.1 mm by the hot embossing process, a compression-induced percolation threshold occurred at 0.3 wt%, while the electrical conductivity was further enhanced to 378 S/m at 8 wt% SCF. Furthermore, the additional of a second nanofiller of 1 wt%, such as carbon nanotube or conducting carbon black further increased the electrical conductivity of the PDMS/SCF (8 wt%) composites to 909 S/m and 657 S/m, respectively. The synergy of the densified conducting filler network by the mechanical compression and the hierarchical micro-/nanoscale filler approach has realize super high electrical conductive yet mechanical flexible polymer composites for modern flexible electronics applications.


2020 ◽  
Vol 38 (3A) ◽  
pp. 431-439
Author(s):  
Akram R. Jabur

Conductive polymer films were prepared of polyvinyl alcohol (PVA) with (0, 2, 4, 6, 8, and 10) wt. % multiwalled carbon nanotubes (MWCNTs) by electrospinning technique. The morphologies of the synthesized films were tested by scanning electron microscopy (SEM). Average fiber diameters gauged statically was (115nm) for (PVA/10 wt. % MWCNT film) while (170nm) for pure PVA electro spun film. Electrical conductivity (EC) of Polymeric nanofiber films improve by increasing MWCNT addition concentration from (3.69 × 10-7 S/ cm) for the pure (PVA) film to (1.24 ×10-2 S/cm) for the film with 10 wt. % MWCNT. The maximum stress of PVA film were increased by adding MWCNTs concentration, the modulus of elasticity was enhanced from 12.87 MPa for pure PVA to 49.89 MPa for PVA/8wt% MWCNT.


2017 ◽  
Vol 4 (12) ◽  
pp. 170769 ◽  
Author(s):  
Xuewei Zhang ◽  
Jiang Liu ◽  
Yi Wang ◽  
Wei Wu

Carbon black (CB)-filled polypropylene (PP) with surface resistivity between 10 6 and 10 9  Ω sq −1 is the ideal antistatic plastic material in the electronics and electric industry. However, a large amount of CB may have an adverse effect on the mechanical properties and processing performance of the material, thus an improved ternary system is developed. Blends of CB-filled PP and polyamide 6 (PA6) have been prepared by melt blending in order to obtain electrically conductive polymer composites with a low electrical percolation threshold based on the concept of double percolation. The morphological developments of these composites were studied by scanning electron microscopy. The results showed that CB particles were selectively dispersed in PA6 phases due to the good interaction and interfacial adhesion between CB and PA6. At the same CB loadings, the surface resistivity of PP/PA6/CB composite was smaller than that of PP/CB composite system, which indicated the better conductivity in the former composite. The increasing amount of PA6 in the composites changed the morphology from a typical sea–island morphology to a co-continuous morphology. What is more, with 8 wt% of CB and PP/PA6 phase ratio of 70/30 in which the PP and PA6 phases formed a co-continuous structure, the electrical conductivity of the composite peaked at 2.01 × 10 5  Ω sq −1 .


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Nishata Royan Rajendran Royan ◽  
Abu Bakar Sulong ◽  
Jaafar Sahari ◽  
Hendra Suherman

Carbon nanotubes (CNTs) have a huge potential as conductive fillers in conductive polymer composites (CPCs), particularly for bipolar plate applications. These composites are prepared using singlefiller and multifiller reinforced multiwalled carbon nanotubes (MWCNTs) that have undergone a chemical functionalization process. The electrical conductivity and mechanical properties of these composites are determined and compared between the different functionalization processes. The results show that UV/O3-treated functionalization is capable of introducing carboxylic functional groups on CNTs. Acid-treated CNT composites give low electrical conductivity, compared with UV/O3-treated and As-produced CNTs. The in- and through-plane electrical conductivities and flexural strength of multifiller EP/G/MWCNTs (As-produced and UV/O3-treated) achieved the US Department of Energy targets. Acid-treated CNT composites affect the electrical conductivity and mechanical properties of the nanocomposites. These data indicate that the nanocomposites developed in this work may be alternative attributers of bipolar plate requirements.


Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 56 ◽  
Author(s):  
Xiaolong Gao ◽  
Yao Huang ◽  
Xiaoxiang He ◽  
Xiaojing Fan ◽  
Ying Liu ◽  
...  

Electrically conductive polymer composites are in high demand for modern technologies, however, the intrinsic brittleness of conducting conjugated polymers and the moderate electrical conductivity of engineering polymer/carbon composites have highly constrained their applications. In this work, super high electrical conductive polymer composites were produced by a novel hot embossing design. The polydimethylsiloxane (PDMS) composites containing short carbon fiber (SCF) exhibited an electrical percolation threshold at 0.45 wt % and reached a saturated electrical conductivity of 49 S/m at 8 wt % of SCF. When reducing the sample thickness from 1.0 to 0.1 mm by the hot embossing process, a compression-induced percolation threshold occurred at 0.3 wt %, while the electrical conductivity was further enhanced to 378 S/m at 8 wt % SCF. Furthermore, the addition of a second nanofiller of 1 wt %, such as carbon nanotube or conducting carbon black, further increased the electrical conductivity of the PDMS/SCF (8 wt %) composites to 909 S/m and 657 S/m, respectively. The synergy of the densified conducting filler network by the mechanical compression and the hierarchical micro-/nano-scale filler approach has realized super high electrically conductive, yet mechanically flexible, polymer composites for modern flexible electronics applications.


2020 ◽  
Vol 1010 ◽  
pp. 638-644
Author(s):  
Mohd Pisal Mohd Hanif ◽  
Abd Jalil Jalilah ◽  
Mohd Fadzil Hanim Anisah ◽  
Arumugam Tilagavathy

Biopolymer-based conductive polymer composites (CPCs) would open up various possibilities in biomedical applications owing to ease of processing, renewable resource and environmentally friendly. However, low mechanical properties are a major issue for their applications. In this study, the investigated the conductivity of chitosan/ PEO blend films filled with carbonized wood fiber (CWF) prepared by solution casting. The effect of CWF was also investigated on tensile properties and their morphological surfaces. The tensile results from different ratios of chitosan/PEO blend films without CWF show that the tensile strength and modulus increased with the increase of chitosan content and chitosan/PEO blend film with 70/30 ratio exhibited the best combination of tensile strength and flexibility. However, a reduction of tensile strength was observed when CWF amount was increased while the modulus of the tensile shows an increment. The film also exhibited higher electrical conductivity as compared to low chitosan ratio. The addition of CWF greatly enhanced the conductivity three-fold from 10-10 to 10-6 S/cm. The electrical conductivity continued to increase with the increase of CWF up to 30wt%. The surface morphology by Scanning Electron Microscopy (SEM) exhibits the absence of phase separation for the blends indicating good miscibility between the PEO and chitosan. Incorporation of CWF into the blend films at 5wt% showed agglomeration. However, the increase of CWF created larger agglomerations that formed conductive pathways resulting in improved conductivity. FTIR analysis suggested that intermolecular interactions occurred between chitosan and PEO while CWF interacts more with the protons of PEO.


Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1355
Author(s):  
Astrid Diekmann ◽  
Marvin C. V. Omelan ◽  
Ulrich Giese

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.


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