scholarly journals Comparison of Three Interfacial Conductive Networks Formed in Carbon Black-Filled PA6/PBT Blends

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2926 ◽  
Author(s):  
Hansong Li ◽  
Xinlin Tuo ◽  
Bao-Hua Guo ◽  
Jian Yu ◽  
Zhao-Xia Guo
Keyword(s):  
Carbon Black ◽  
Polymer Blends ◽  
High Efficiency ◽  
Network Formation ◽  
Polyamide 6 ◽  
Formation Mechanisms ◽  
Network Structures ◽  
Practical Applications ◽  
Electrical Percolation ◽  
Carbon Fillers

Interfacial localization of carbon fillers in cocontinuous-structured polymer blends is well-known as a high-efficiency strategy for conductive network formation. However, a comparison with interfacial localization of carbon fillers in sea-island-structured polymer blends is lacking. Here, three types of highly efficient conductive networks formed on the basis of interfacial localization of carbon black (CB) in polyamide 6 (PA6)/poly(butylene terephthalate) (PBT) blends with different blend compositions (80/20, 50/50 and 20/80 vol/vol) were investigated and compared in terms of electrical resistivity, morphology as well as rheological and mechanical properties. The order of the electrical percolation threshold of CB in the three blends is 50/50 < 20/80 < 80/20, which can be attributed to different network structures. The rheological percolation thresholds are close to the electrical ones, confirming the formation of CB networks. The formation mechanisms for the three types of CB network structures are analyzed. All the three types of PA6/PBT-6 vol% CB composites showed improved tensile strength compared with PA6/PBT blends, being in favor for practical applications.

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.

scholarly journals Effect of polyamide 6 on the morphology and electrical conductivity of carbon black-filled polypropylene composites

2017 ◽  
Vol 4 (12) ◽  
pp. 170769 ◽  
Author(s):  
Xuewei Zhang ◽  
Jiang Liu ◽  
Yi Wang ◽  
Wei Wu
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Plastic Material ◽  
Conductive Polymer ◽  
Polyamide 6 ◽  
Surface Resistivity ◽  
Electric Industry ◽  
Polypropylene Composites ◽  
Electrical Percolation ◽  
Double Percolation

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 .

Modeling the electrical percolation of mixed carbon fillers in polymer blends

Carbon ◽  
2014 ◽  
Vol 70 ◽  
pp. 233-240 ◽  
Author(s):  
Zhuo-Yue Xiong ◽  
Bo-Yuan Zhang ◽  
Li Wang ◽  
Jian Yu ◽  
Zhao-Xia Guo
Keyword(s):  
Polymer Blends ◽  
Electrical Percolation ◽  
Carbon Fillers

scholarly journals Chemical Modification of Combusted Coal Gangue for U(VI) Adsorption: Towards a Waste Control by Waste Strategy

2021 ◽  
Vol 13 (15) ◽  
pp. 8421
Author(s):  
Yuan Gao ◽  
Jiandong Huang ◽  
Meng Li ◽  
Zhongran Dai ◽  
Rongli Jiang ◽  
...  
Keyword(s):  
Structural Analysis ◽  
High Efficiency ◽  
Low Cost ◽  
Chemical Activation ◽  
Cost Effective ◽  
Coal Gangue ◽  
Order Kinetic ◽  
Practical Applications ◽  
Detailed Structural Analysis ◽  
Alkaline Conditions

Uranium mining waste causes serious radiation-related health and environmental problems. This has encouraged efforts toward U(VI) removal with low cost and high efficiency. Typical uranium adsorbents, such as polymers, geopolymers, zeolites, and MOFs, and their associated high costs limit their practical applications. In this regard, this work found that the natural combusted coal gangue (CCG) could be a potential precursor of cheap sorbents to eliminate U(VI). The removal efficiency was modulated by chemical activation under acid and alkaline conditions, obtaining HCG (CCG activated with HCl) and KCG (CCG activated with KOH), respectively. The detailed structural analysis uncovered that those natural mineral substances, including quartz and kaolinite, were the main components in CCG and HCG. One of the key findings was that kalsilite formed in KCG under a mild synthetic condition can conspicuous enhance the affinity towards U(VI). The best equilibrium adsorption capacity with KCG was observed to be 140 mg/g under pH 6 within 120 min, following a pseudo-second-order kinetic model. To understand the improved adsorption performance, an adsorption mechanism was proposed by evaluating the pH of uranyl solutions, adsorbent dosage, as well as contact time. Combining with the structural analysis, this revealed that the uranyl adsorption process was mainly governed by chemisorption. This study gave rise to a utilization approach for CCG to obtain cost-effective adsorbents and paved a novel way towards eliminating uranium by a waste control by waste strategy.

2,6-Dibromogallates as a new building block for controlling π-stacking, network formation and mirror symmetry breaking

2021 ◽  
Author(s):  
Ohjin Kwon ◽  
Xiaoqian Cai ◽  
Azhar Saeed ◽  
Feng Liu ◽  
Silvio Poppe ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Building Block ◽  
Mirror Symmetry ◽  
Network Formation ◽  
Network Structures ◽  
Π Stacking ◽  
Bicontinuous Cubic ◽  
Substituted 1 ◽  
End Group

Achiral multi-chain (polycatenar) compounds based on the 2,7-diphenyl substituted [1]benzothieno[3,2-b]benzothiophene (BTBT) unit and a 2,6-dibromo-3,4,5-trialkoxybenzoate end group lead to materials forming bicontinuous cubic liquid crystaline phases with helical network structures...

scholarly journals Vacancy tuned thermoelectric properties and high spin filtering performance in graphene/silicene heterostructures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zainab Gholami ◽  
Farhad Khoeini
Keyword(s):  
Electric Fields ◽  
High Spin ◽  
High Efficiency ◽  
Practical Applications ◽  
External Electric Fields ◽  
Ferromagnetic Exchange ◽  
High Spin Polarization ◽  
Filtering Effect ◽  
Spin Switching ◽  
Spin Filtering

AbstractThe main contribution of this paper is to study the spin caloritronic effects in defected graphene/silicene nanoribbon (GSNR) junctions. Each step-like GSNR is subjected to the ferromagnetic exchange and local external electric fields, and their responses are determined using the nonequilibrium Green’s function (NEGF) approach. To further study the thermoelectric (TE) properties of the GSNRs, three defect arrangements of divacancies (DVs) are also considered for a larger system, and their responses are re-evaluated. The results demonstrate that the defected GSNRs with the DVs can provide an almost perfect thermal spin filtering effect (SFE), and spin switching. A negative differential thermoelectric resistance (NDTR) effect and high spin polarization efficiency (SPE) larger than 99.99% are obtained. The system with the DV defects can show a large spin-dependent Seebeck coefficient, equal to Ss ⁓ 1.2 mV/K, which is relatively large and acceptable. Appropriate thermal and electronic properties of the GSNRs can also be obtained by tuning up the DV orientation in the device region. Accordingly, the step-like GSNRs can be employed to produce high efficiency spin caloritronic devices with various features in practical applications.

scholarly journals Ruthenium Sensitizers and Their Applications in Dye-Sensitized Solar Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-21 ◽  
Author(s):  
Yuancheng Qin ◽  
Qiang Peng
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Low Cost ◽  
Dye Sensitized Solar Cells ◽  
Ruthenium Complexes ◽  
Practical Applications ◽  
Photovoltaic Energy ◽  
Dye Sensitized ◽  
Sensitized Solar Cells ◽  
Excellent Stability

Dye-sensitized solar cells (DSSCs) have attracted considerable attention in recent years due to the possibility of low-cost conversion of photovoltaic energy. The DSSCs-based ruthenium complexes as sensitizers show high efficiency and excellent stability, implying potential practical applications. This review focuses on recent advances in design and preparation of efficient ruthenium sensitizers and their applications in DSSCs, including thiocyanate ruthenium sensitizers and thiocyanate-free ruthenium sensitizers.

scholarly journals Kinetic analyses of vasculogenesis inform mechanistic studies

2017 ◽  
Vol 312 (4) ◽  
pp. C446-C458 ◽  
Author(s):  
Kaela M. Varberg ◽  
Seth Winfree ◽  
Chenghao Chu ◽  
Wanzhu Tu ◽  
Emily K. Blue ◽  
...  
Keyword(s):  
Network Formation ◽  
De Novo ◽  
Structural Connectivity ◽  
Maternal Diabetes ◽  
Time Correlation ◽  
Network Structures ◽  
Cellular Mechanisms ◽  
Kinetic Measurements ◽  
Over Time

Vasculogenesis is a complex process by which endothelial stem and progenitor cells undergo de novo vessel formation. Quantitative assessment of vasculogenesis is a central readout of endothelial progenitor cell functionality. However, current assays lack kinetic measurements. To address this issue, new approaches were developed to quantitatively assess in vitro endothelial colony-forming cell (ECFC) network formation in real time. Eight parameters of network structure were quantified using novel Kinetic Analysis of Vasculogenesis (KAV) software. KAV assessment of structure complexity identified two phases of network formation. This observation guided the development of additional vasculogenic readouts. A tissue cytometry approach was established to quantify the frequency and localization of dividing ECFCs. Additionally, Fiji TrackMate was used to quantify ECFC displacement and speed at the single-cell level during network formation. These novel approaches were then implemented to identify how intrauterine exposure to maternal diabetes mellitus (DM) impairs fetal ECFC vasculogenesis. Fetal ECFCs exposed to maternal DM form fewer initial network structures, which are not stable over time. Correlation analyses demonstrated that ECFC samples with greater division in branches form fewer closed network structures. Additionally, reductions in average ECFC movement over time decrease structural connectivity. Identification of these novel phenotypes utilizing the newly established methodologies provides evidence for the cellular mechanisms contributing to aberrant ECFC vasculogenesis.

scholarly journals Synergistic Interfacial and Doping Engineering of Heterostructured NiCo(OH)x-CoyW as an Efficient Alkaline Hydrogen Evolution Electrocatalyst

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruopeng Li ◽  
Hao Xu ◽  
Peixia Yang ◽  
Dan Wang ◽  
Yun Li ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
High Efficiency ◽  
Low Voltage ◽  
Electrochemical Etching ◽  
Synergistic Effects ◽  
Release Kinetics ◽  
Water Electrolysis ◽  
Water Dissociation ◽  
Practical Applications ◽  
Environmentally Friendly Process

AbstractTo achieve high efficiency of water electrolysis to produce hydrogen (H2), developing non-noble metal-based catalysts with considerable performance have been considered as a crucial strategy, which is correlated with both the interphase properties and multi-metal synergistic effects. Herein, as a proof of concept, a delicate NiCo(OH)x-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition, followed by an electrochemical etching-growth process, which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction, with an overpotential of 21 and 139 mV at 10 and 500 mA cm−2, respectively. Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)x/CoyW heterogeneous interface resulted in favorable electron redistribution and faster electron transfer efficiency. The amorphous NiCo(OH)x strengthened the water dissociation step, and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H2 desorption. In addition, NiCo(OH)x-CoyW exhibited desirable urea oxidation reaction activity for matching H2 generation with a low voltage of 1.51 V at 50 mA cm−2. More importantly, the synthesis and testing of the NiCo(OH)x-CoyW catalyst in this study were all solar-powered, suggesting a promising environmentally friendly process for practical applications.

Endothelial k-RasV12 Expression Induces Capillary Deficiency Attributable to Marked Tube Network Expansion Coupled to Reduced Pericytes and Basement Membranes

2021 ◽  
Author(s):  
Zheying Sun ◽  
Scott S. Kemp ◽  
Prisca K. Lin ◽  
Kalia N. Aguera ◽  
George E. Davis
Keyword(s):  
Protein Kinase ◽  
Basement Membrane ◽  
Arteriovenous Malformations ◽  
Network Formation ◽  
Tube Formation ◽  
Small Gtpase ◽  
Basement Membranes ◽  
Formation Mechanisms ◽  
Lumen Formation ◽  
The Impact

Objective: We sought to determine how endothelial cell (EC) expression of the activating k-Ras mutation, k-RasV12, affects their ability to form lumens and tubes and interact with pericytes during capillary assembly Approach and Results: Using defined bioassays where human ECs undergo observable tubulogenesis, sprouting behavior, pericyte recruitment to EC-lined tubes, and pericyte-induced EC basement membrane deposition, we assessed the impact of EC k-RasV12 expression on these critical processes that are necessary for proper capillary network formation. This mutation, which is frequently seen in human ECs within brain arteriovenous malformations, was found to markedly accentuate EC lumen formation mechanisms, with strongly accelerated intracellular vacuole formation, vacuole fusion, and lumen expansion and with reduced sprouting behavior, leading to excessively widened tube networks compared with control ECs. These abnormal tubes demonstrate strong reductions in pericyte recruitment and pericyte-induced EC basement membranes compared with controls, with deficiencies in fibronectin, collagen type IV, and perlecan deposition. Analyses of signaling during tube formation from these k-RasV12 ECs reveals strong enhancement of Src, Pak2 (P21 [RAC1 (Rac family small GTPase 1)] activated kinase 2), b-Raf (v-raf murine sarcoma viral oncogene homolog B1), Erk (extracellular signal–related kinase), and Akt activation and increased expression of PKCε (protein kinase C epsilon), MT1-MMP (membrane-type 1 matrix metalloproteinase), acetylated tubulin and CDCP1 (CUB domain-containing protein 1; most are known EC lumen regulators). Pharmacological blockade of MT1-MMP, Src, Pak, Raf, Mek (mitogen-activated protein kinase) kinases, Cdc42 (cell division cycle 42)/Rac1, and Notch markedly interferes with lumen and tube formation from these ECs. Conclusions: Overall, this novel work demonstrates that EC expression of k-RasV12 disrupts capillary assembly due to markedly excessive lumen formation coupled with strongly reduced pericyte recruitment and basement membrane deposition, which are critical pathogenic features predisposing the vasculature to develop arteriovenous malformations.

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