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The dramatic changes the world and the expectations of potential users have pushed researchers working in flexible foam pressure sensor (FFPS) fabrication to develop more affordable and high-performance materials. Among various materials, polymer foamed-based nanocomposites are a preferred choice due to their excellent mechanical properties, good chemical properties, and easy control. Moreover, the use of nanofillers such as carbon nanotubes (CNTs), carbon black (CB), and graphene in the polymer matrix has greatly improved the properties of the sensors. Therefore, this review focuses on the recent advances in FFPS by using different types of nanofillers in shape and structure. Accordingly, developments in the fabrication of FFPS, including dip coating, spray coating, sputtering, and in situ polymerization are also discussed. Special attention has been paid to identifying the underlying mechanism to maximize pressure sensing and improve the performance of FFPS. Suggestions for future developments in the area of sensing devices applied in health monitoring are also presented. [ABSTRACT FROM AUTHOR]

Stretchable conductors are important ingredients in the new emerging wearable systems. Here, intrinsically stretchable con-ductors (ISCs) based on carbon nanomaterials with a good balance of properties are prepared through synergistic combination of graphene and carbon black (CB) into the matrices of thermoplastic polyurethane (TPU). The inks are prepared through mixing graphene and CB with adjustable mass ratios in TPU by ball-milling, which can be used for blade-coating or 3D-printing. The ISCs prepared by drying the inks at room temperature afford an initial conductivity of 12.5 S cm-1 with an elongation of 140%, or 62.5 S cm-1 with an elongation of 20%, comparable to the carbon nanotube based ISCs. The whole performance is better than those of composites with only one filler (graphene or CB), suggesting the synergistic effect between graphene and CB. Furthermore, the composites with binary fillers have stable electromechanical properties for 1000 cycles of stretching and releasing. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor for the determination of triclosan (TCS) based on acetylene black (AB)/carbon nanotube (CNT)/cetyl sulphonyl betaine (SB16) was prepared. The composite AB/CNT/SB16 sensor was constructed using AB electrode with CNT and SB16 as sensitising materials. Sensor performance was evaluated by cyclic voltammetry, scanning electron microscopy and electrochemical impedance spectroscopy analyses. The linear equation was Ip(μA) = 19.16CTCS(μM) + 0.1319(R2 = 0.9823), and the linear range of the prepared method for the detection of TCS was from 0.01 μM to 2.0 μM with a detection limit of 6.18 nM. The sensor also displayed excellent selectivity, repeatability, and stability for TCS determination. Finally, the sensor was successfully used to detect TCS in real commodity samples, with a relative standard deviation from 0.56% to 2.32%, consistent with the results of high-performance liquid chromatography. [ABSTRACT FROM AUTHOR]

In this work, XLPE/MWCNT and XLPE/CB nanocomposites have been prepared in order to investigate AC electric field and water effects on electrical aging of XLPE. The mechanical, AC breakdown strength and AC conductivity were tested and the morphologies after 30 days electrical aging were observed using an optical microscope. The results showed that all samples exhibit excellent insulation properties and mechanical properties. Compared with CB addition, the MWCNT composites exhibit better resistance to electrical aging, with the length of electrical aging-induced microcracks in the MWCNT blends decreasing from 104 to 22 µm, and the width decreasing from 87 to 17 µm, which means a reduction of ∼80% compared of values for neat XLPE in both length and width. However, the XLPE/CB composites have a tendency to promote electrical aging. The mechanism is revealed by comparing the results of the fibrous MWCNTs with the spherical CBs. [ABSTRACT FROM AUTHOR]

Carbonaceous nanomaterials (CNMs) are universally being used to make commodities, as they present unique opportunities for development and innovation in the fields of engineering, biotechnology, etc. As technology advances to incorporate CNMs in industry, the potential exposures associated with these particles also increase. CNMs have been found to be associated with substantial pulmonary toxicity, including inflammation, fibrosis, and/or granuloma formation in animal models. This study attempts to categorize the toxicity profiles of various carbon allotropes, in particular, carbon black, different multi-walled carbon nanotubes, graphene-based materials, and their derivatives. Statistical and machine learning-based approaches were used to identify groups of CNMs with similar pulmonary toxicity responses from a panel of proteins measured in bronchoalveolar lavage (BAL) fluid samples and with similar pathological outcomes in the lungs. Thus, grouped particles, based on their pulmonary toxicity profiles, were used to select a small set of proteins that could potentially identify and discriminate between the toxicity profiles associated within each group. Specifically, MDC/CCL22 and MIP-3β/CCL19 were identified as common protein markers associated with both toxicologically distinct groups of CNMs. In addition, the persistent expression of other selected protein markers in BAL fluid from each group suggested their ability to predict toxicity in the lungs, i.e. fibrosis and microgranuloma formation. The advantages of such approaches can have positive implications for further research in toxicity profiling. [ABSTRACT FROM AUTHOR]

In this article, a kind of conical cup-stacked carbon nanotubes (CSCNTs) grown by the microwave irradiation of the mixture of ferrocene and carbon black nanoparticles is reported. They are characterized by the long-cone shape, the nearly unchanged wall thickness and the huge hollow core. SEM and TEM analyses reveal that they are formed by the stacking of the truncated conical graphene layers precipitated from the surfaces of catalysts. The motions and coalescences of catalysts result in the increase of catalyst size during reaction. At the same time, the inner diameter of the truncated conical graphite layer precipitated from the surface of catalyst can increase with the catalyst size continuously. As a result, the as-grown CSCNTs have the conical hollow core and almost unchanged wall thickness. To the best of our knowledge, this kind of conical CSCNTs has been reported for the first time. [ABSTRACT FROM AUTHOR]

A rapid, effective and sensitive method to quantitatively determine six fungicide residue was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC–MS/MS). The target compounds were extracted by using acetonitrile and the sorbent used for clean-up in this modified QuEChERS analytical method were biochar, multiwalled carbon nanotubes (MWCNT) and graphitized carbon black (GCB). Results indicated that the MWCNT (10 mg) was the most effective sorbent in removing pigment. This method was validated on spinach, tomato, cucumber, celery, lettuce, rape, pakchoi, romaine lettuce and eggplant matrices spiked at three concentration levels of 0.01, 0.1 and 1 mg kg−1. It exhibited recoveries between 73.1% and 118.2% with RSD values below 20%. Matrix-matched calibrations were performed with the coefficients of determination >0.9901 between concentration levels of 0.01–1 mg kg−1. The limit of quantity (LOQ) for six pesticides ranged from 0.0036 to 0.011 mg kg−1. The developed method was satisfactorily applied to determine pesticide residues in market vegetable samples. [ABSTRACT FROM AUTHOR]

Current paper provides a comprehensive review of carbon nanostructure supported hydrodesulfurization (HDS) catalysts as well as serving as a guide to explore such compounds. In this venue, variety of such structures including activated carbon (AC), carbon black (CB), carbon black composite (CBC), carbon nanotubes (CNT) of single and multi-walled nature, carbon nanofibers (CNF), graphite, graphene as graphene oxide (GO) and reduced graphene oxides (rGO) and fullerenes have been discussed and their physiochemical properties have been provided. Moreover, a thorough comparison of the active phase distribution and catalyst morphology and the reaction pathways of carbon and commonly used γ-Al2O3 supports performed. This study further emphasizes upon the desirable weaker interactions between carbon based materials and the active metal phases as well as pore size distributions and specific surface area, which are all key factors leading to better HDS performance of such materials. Nonetheless, some shortcomings of these materials also mentioned. Ultimately, the effects of carbonaceous species on solubility, dispersion capabilities and chemical stabilities toward obtaining highly effective catalysts discussed. [ABSTRACT FROM AUTHOR]

The use of polystyrene-based materials has become very important due to a wide range of industrial applications. Different types of nanofillers such as fullerene, carbon black, graphite, graphene, and carbon nanotube have been used with polystyrene to attain high-performance materials. Fabrication and unique properties of composites are considered here. Use of fullerene to improve thermal stability of polystyrene/fullerene composite has been explored. Polystyrene /carbon black composite have found to improve thermal, electrical, and rheological properties. Polystyrene/graphite nanosheet composite have been used in different applications due to mechanical and electrical properties. Polystyrene/carbon nanotube composite have been studied for enhanced tribological properties. [ABSTRACT FROM AUTHOR]

Controlling the chemistry on the surface of new carbon materials is a key factor to widen the range of their applicability. In this paper we show a grafting methodology of polyalkylamines to the surface of carbon nanomaterials, in particular, carbon nanotubes and a carbon black. The aim of this work is to reach large degrees of covalent functionalization with hyperbranched polyethyleneimines (HBPEIs) and to efficiently preserve the strong chelating properties of the HBPEIs when they are fixed to the surface of these carbon materials. This functionalization opens new possibilities of using these carbon nanotubes-based hybrids. The results show that the HBPEIs are covalently attached to the carbon materials, forming hybrids. These hybrids emerge from the reaction of amine functions of the HBPEIs with carbonyls and carboxylic anhydrides of the carbon surface which become imine and imide bonds. Thus, due to the nature of these bonds, the pre-oxidized samples with relevant number of C=O groups showed an increase in the degree of functionalization with the HBPEIs. Furthermore, both the acid-base properties and the coordination capacity for metal ions of the hybrids are equivalent to that of the free HBPEIs in solution. This means that the chemical characteristics of the HBPEIs have been efficiently transferred to the hybrids. To reach this conclusion we have developed a novel procedure to assess the acid-base and the coordination properties of the hybrids (solids) by means of potentiometric titration. The good agreement of the values obtained for the hybrids and for the free HBPEIs in aqueous solution supports the reliability of the procedure. Moreover, the high capacity of the hybrids to capture Ni2+by complexation opens new possibilities of using these hybrids to capture high-value metal ions such as Pd2+and Pt2+. Hyperbranched polyethylenimines are covalently fixed to the surface of carbon materials, so the chemical characteristics of the amines are transferred to the hybrid materials. [ABSTRACT FROM AUTHOR]

Silicone rubber (SR) filled with different concentrations of carbon nanotubes (CNTs), carbon black (CB) and (CNTs/CB) hybrid fillers was fabricated by melt blending. The effects of filler type on the electrical properties and piezoresistive properties (in the region of the percolation) of the conductive SR composites were studied. Percolation threshold of CNTs, CB and (CNTs/CB) based composites was found to be 0.20, 0.255 and 0.22 volume fraction respectively. The piezoresistive sensitivity GR of these conductive SR composites, dependent on different filler types, was 0.8549, 0.7267 and 0.9361 respectively. Compared to CB/SR and CNTs/SR, CNTs/CB/SR revealed an unexpectedly high GR, which indicated that the synergistic effects have formed in CNTs/CB network. In addition, microscopic analysis (SEM) can also explain the existence of synergies. A model describing the electrical percolation of mixed carbon fillers CNTs and CB is proposed. The experimental value (0.22) of hybrid filler systems is smaller than the theoretical value (0.23), which can prove the existence of synergies once again. [ABSTRACT FROM AUTHOR]

Multiwalled nanotube (MWNT)/fluoroelastomer (FKM) composites were synthesised through a simple and cost efficient method. MWNTs were dispersed in the FKM by an open two-roll mill followed by vulcanisation inside a compression moulding machine. The morphologies and rheological and mechanical properties of the MWNT/FKM composites with different MWNT mass fractions were systematically investigated. Compared with the carbon black (CB)/FKM composites fabricated via the same method, the MWNT/FKM composites demonstrated higher degree of crosslinking and better mechanical properties. By adding 5 wt-% MWNTs in the FKM matrix, the hardness, tensile strength and abrasion resistance of the FKM were significantly improved by 12, 120 and 13% respectively. Compared to CB, MWNTs show higher reinforcing efficiency due to their higher aspect ratio and surface area that result in higher crosslink density and stronger filler–polymer interaction. [ABSTRACT FROM AUTHOR]

We investigated the influence of carbon materials on the properties of adhesives. With the aim of the development of conductive and mechanically improved adhesives, different types of multi-walled carbon nanotubes (MWNT), single-layer graphene, graphene nanoplatelets, graphite, and carbon black were dispersed into an epoxy adhesive. For inserting particles within the viscous matrices and to obtain homogenous and stable dispersions, two different methods namely a three-roll mill and a dual asymmetric centrifuge have been compared The results demonstrate that filling epoxies with carbon nanoparticles improves the conductivity differently. Measuring the electrical resistivity of MWNT-filled composites resulted in an electrical percolation starting underneath 0.1 wt.%. Further, with increasing the MWNT content, conductivity sharply increases. In contrast to the MWNT composites, other carbon nanoparticles require a higher filling content to reach similar values. With a filling ratio up to 17.0 wt.% for ACS graphene nanoplatelets 2–10 nm and the filling of 3.0 wt.% with MWNTs from Nanocyl, the lowest volume resistivities have been reached. [ABSTRACT FROM PUBLISHER]

Hollow graphitic carbon nanoparticles (HGCNs) obtained by catalytic graphitization of acetylene carbon black (ACB) were investigated using ultra-soft X-ray emission spectroscopy. The electronic structures of the ACB HGCNs were compared with those of HGCNs obtained from iron carbide-filled carbon nanocapsules (Fe3C@CNCs) and Q-graphenes. The occupation of the π sub-band decreased in the following sequence: Fe3C@CNC HGCNs > ACB HGCNs > Q-graphenes. This sequence can be explained by changes in the occupations of the C2p states due to the formation of bonds between carbon and residual metal atoms within the HGCNs. It was also found that the contribution of the overlapping ofppπ+ppσ-states in the ACB HGCN walls toward the spectra of the HGNCs was greater in comparison with the reference Q-graphenes. It was established that ACB was not fully transformed into the HGCNs. Scanning and transmission electron microscopy methods were used to study the spatial structures and morphologies of the fabricated HGCNs. [ABSTRACT FROM PUBLISHER]

Properties of natural rubber (NR) filled with hybrid fillers were compared. Loading of the primary filler, carbon black (CB), was fixed whereas that of the secondary fillers, carbon nanotube (CNT) and conductive carbon black (CCB), was varied. The increase of secondary filler loading results in loss of elasticity but the increases of viscosity, vulcanization rate, cross-link density, hardness, modulus, thermal and electrical conductivities and tan δ. Obviously, CNT gives stronger effect than CCB. However, CCB gives improvement in tensile and tear strengths when added up to 3 phr whereas the addition of CNT shows no significant effect on the strengths. [ABSTRACT FROM PUBLISHER]