Acetone Dispersion Research Articles

Nanocomposites Produced with the Addition of Carbon Nanotubes Dispersed on the Surface of Cement Particles Using Different Non-Aqueous Media

The inclusion of carbon nanotubes (CNTs) in cementitious composites has been studied due to their electrical, thermal, and mechanical enhancing properties. Considering the hydrophobic characteristics of CNTs, these nanomaterials need to be well dispersed in the aqueous media in which they are inserted to guarantee those gains. Among the methods applied to produce such composites is the dispersion of CNTs on the surface of anhydrous cement particles using non-aqueous suspensions such as acetone, ethanol, or isopropanol. Even though those non-aqueous media have been individually studied by researchers, comparisons of the efficiency of CNTs dispersion was not found in the literature. Therefore, as a novelty, the present article aims to analyze the influence of the addition of the multi-walled CNTs dispersed in the cited three types of non-aqueous suspensions on the cement paste’s electrical and mechanical properties. Pastes containing 0%, 0.5%, and 1.0% of CNTs were prepared on the surface of anhydrous cement particles using a pre-dispersion technique based on simultaneous sonication and mechanical agitation in the three cited media. Tests to determine electric-volumetric resistivity, compressive strength, and splitting tensile strength were performed. It was observed that acetone dispersion decreases the cement paste’s electrical resistivity, even without the addition of CNTs. The cementitious composites with CNTs demonstrated increased mechanical strength (both compressive and tensile) using all three dispersion media. Statistical analysis (analysis of variance—ANOVA—and Tukey’s Test) was performed to evaluate the significance of the results.

Some characteristics of purpurin-18synthesised from chlorophyll a of Spirulina

Research and synthesis of photosensitive purpurin 18 (Pp-18) from nature is one of the topics that many research groups are interested in and developing. In this study, the authors defined some characteristics of Pp-18 synthesised from chlorophyll a - a substance isolated from Spirulina. The results showed that Pp-18 had good dispersion in acetone at 478.5 nm (R2=0.98285) and reached 98%. Fluorescence spectroscopy of Pp-18 in acetone was measured at a concentration of 70 ppm, wavelengths 365.39, 417.62, and 557.96 nm. The fluorescence lifetime of Pp-18 in acetone solution was 2.85 ns.

Nonlinear optical limiting effect of graphene dispersions at 1064 nm.

We study the nonlinear optical limiting effect of graphene dispersions in ethanol and acetone at a wavelength of 1064 nm. The nonlinear optical limiting effect of graphene dispersion under three different linear transmittances (about 70%, 80%, and 90%), two different thicknesses (1 and 3 cm), and two different solvents (ethanol and acetone) are measured. The influences of concentration, thickness, and solvent on the nonlinear optical limiting effect of the graphene dispersion are analyzed. The experimental results show that the concentration and solution thicknesses have great influence on the optical limiting ability of graphene dispersions. The graphene dispersions with ethanol and acetone as solvents can be used to achieve excellent nonlinear optical limiting effects. The optical limiting ability of the graphene dispersion in acetone is better than that of the graphene dispersion in ethanol.

Synthesis and Characterization of Lignin-grafted-poly(ε-caprolactone) from Different Biomass Sources

Modification of lignin with poly(ε-caprolactone) is a promising approach to valorize industrial low-value lignins and to advance the bioeconomy. We have synthesized lignin grafted poly(ε-caprolactone) (lignin-g-PCL) copolymers via ring-opening polymerization of ε-caprolactone with different types of lignins of varying botanical sources (G-type pine lignin, S/G-type poplar lignin, and C-type Vanilla seeds lignin) and lignin extraction methods (Kraft and ethanol organosolv pulping). The lignin-g-PCL copolymer showed remarkably improved compatibility and dispersion in acetone, chloroform, and toluene in comparison to non-modified lignins. The structure and thermal properties of the lignin-g-PCL were investigated using Fourier-transform infrared spectroscopy (FTIR), 31P nuclear magnetic resonance (NMR), 2D heteronuclear single quantum correlation (HSQC) NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). We have found that all the technical lignins were reactive to the copolymerization reaction regardless of their plant source and isolation methods. The molecular weights of the synthesized lignin-g-PCL copolymers were positively correlated with the content of aliphatic lignin hydroxyls, suggesting that the copolymerization reaction tends to occur preferentially at the aliphatic hydroxyls rather than the phenolic hydroxyls of lignin. Thermal analyses of the lignin-g-PCL copolymers were studied, and in general, a reduction of melting temperature and crystallinity percentage in comparison to the neat PCL was observed. However, the thermal behavior of lignin-g-PCL copolymers varied depending on the lignin feedstocks employed in the copolymerization reaction.

GO film on flexible substrate: An approach to wearable colorimetric humidity sensor

Graphene and graphene oxides have outstanding electrical and optical properties, making it particularly interesting in the field of gas sensing. In this study, colorimetric humidity sensor based on graphene oxide (GO) thin film on different substrates was fabricated by using dip coating technique. The fabrication conditions that influence the humidity response were systematically investigated and optimized. Our results indicated that GO thin film on metallized polyethylene terephthalate (mPET) film displayed poor resolution and sensitivity if it was fabricated from aqueous dispersion. However, both spectra resolution and reflectance color of GO film on mPET are enhanced, if it was fabricated from acetone dispersion. It was attributed to the wetting property of solvent that help to form uniform d-spacing of GO sheet assemblies as revealed from XRD analysis. Bending test of the formed GO film on mPET showed an extreme spectra stability upon 10,000 cycles of bending, suggesting that the devices are quite suitable for flexible device applications in both personal physiological condition monitoring and environment condition change detection.

Superacid-Catalyzed Preparation of Highly Dispersible Zirconium Oxide and Titanium Oxide Nanoparticles Without Hydrocarbon Units.

Highly dispersible, hydrocarbon-free zirconium oxide and titanium oxide nanoparticles (ZrO₂-NTf₂- NP and TiO₂-NTf₂-NP) were successfully prepared via the simple sol-gel reactions of zirconium tetra-n-butoxide and titanium tetra-n-butoxide, respectively, using a water/methanol mixed solution of the bis(trifluoromethanesulfonyl)imide superacid. ZrO₂-NTf₂-NP could be dispersed in acetone, ethanol, methanol, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and water, whereas TiO₂-NTf₂-NP could be dispersed in acetone, DMF, DMSO, and water. The number-average particle sizes of ZrO₂-NTf₂-NP and TiO₂-NTf₂-NP were determined to be 3.6±0.6 nm and 5.8±1.1 nm; these values were obtained by dynamic light-scattering measurements of the acetone dispersions (1.0 w/v%). Highly dispersible ZrO₂ nanoparticles could be prepared using other acid catalysts containing trifluoromethyl groups, such as trifluoromethanesulfonic acid and trifluoroacetic acid. In contrast, dispersible TiO₂ nanoparticles could not be prepared using these acid catalysts.

Morphology stability of polymethylmethacrylate nanospheres formed in water–acetone dispersion medium

The aim of this study is to develop a manufacturing technique of polymethylmethacrylate (PMMA) nanospheres to produce a more stable opal template. Water–acetone mixture was used as a dispersion medium to synthesize a PMMA opal structure. Morphology features, IR vibrational spectra and glass transition temperatures of the PMMA nanospheres formed in the water–acetone dispersion medium (nanospheres A) have been studied comparing with the same prepared in distilled water solution without acetone (nanospheres B). A dependence of a shrinkage degree of the nanoparticles on the acetone volume has been investigated. It has been revealed that under an electron beam action the shrinkage degree of the nanospheres A is in the range of 7–16% while the shrinkage of the nanospheres B is 18–25% at the same conditions. The nanospheres A are less flexible and soft as compared to the nanospheres B. Additionally, an ability of the PMMA nanoparticles fabricated in the water–acetone dispersion medium to form the ordered opal structures is demonstrated to be the similar to the nanospheres B.

Flexible graphene-coated carbon fiber veil/polydimethylsiloxane mats as electrothermal materials with rapid responsiveness

Flexible electrothermal mats with rapid responsiveness were prepared by spray-coating of graphene nanoplates (GNP) acetone dispersion on carbon fiber veil and following curing of polydimethylsiloxane (PDMS) on the mats. Morphological feature, electrical property, and electrothermal behavior of the mats with different area density from 55 to 20 g m−2 were investigated. Scanning electronic microscope (SEM) confirmed that pristine graphene nanoplates were uniformly deposited on the surface of carbon fiber resulting in volume resistance decreased substantially. Compared with the carbon fiber veil without coated GNP, the electric heating behavior of graphene-coated carbon fiber/PDMS mats were improved largely, such as the stead-state maximum temperature reached 297 °C, the maximum heating rate reached 5°Cs−1 tested by an infrared camera, the maximum power density reached 11.11 kW m−2. The respond time from room temperature 25 °C–200 °C was only 40 s tested by infrared thermal image. Even under high twisting/bending state or continuous stepwise voltage changes, the graphene-coated carbon fiber/PDMS mats retained stable electrical heating performance in aspects of temperature responsiveness and steady-state maximum temperature.

Synthesis of Linseed Oil-Based Waterborne Urethane Oil Wood Coatings.

The linseed oil glyceride (LOG) was synthesized by using a transesterification process with a glycerol/linseed oil molar ratio of 1.0. The waterborne urethane oil (WUO) wood coating was prepared by acetone process. First, dimethylolpropionic acid was reacted with hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI), followed by adding LOG at various NCO/OH molars of 0.7, 0.8, and 0.9, respectively, and the COOH-containing prepolymer was obtained. Then, the ionomer which was prepared by neutralizing prepolymer with trimethylamine, was dispersed by adding deionized water, and the water–acetone dispersion was obtained. Finally, the acetone was removed by vacuum distillation. In the whole synthesized process, the LOG and COOH-containing prepolymer could be steadily synthesized by FTIR analysis, and the weight-average molecular weight and polydispersity of COOH-containing prepolymer increased with an increase of NCO/OH molar ratios. During the water dispersion process of the ionomer acetone solution, the point of phase inversion was prolonged, meaning the solid content decreased with an increase of NCO/OH molar ratios. After acetone was removed, the color of WUO was milky-white, and it was weakly alkaline and possessed a pseudoplastic fluid behavior. The particle size of WUO increased with increasing of NCO/OH molar ratios, however, the storage stability was extended for HDI and shortened for IPDI synthesized with increasing of NCO/OH molar ratios.

Characteristics of process‐induced properties in carbon nanofibre aqueous dispersion

This work presents the experimental and statistical characterisation of carbon nanofibres (CNFs) dispersed in acetone. The purpose of the work is to study the process-induced properties in CNF aqueous dispersion. Dispersing techniques such as sonication and high shear-speed mixing were provided to disperse the CNFs. Response surface methodology was used here to design experiments and predict the nanoparticle size distribution after the dispersion. The effect of dispersing techniques and CNF concentration on nanofibre dispersion in acetone was investigated by quantitative and qualitative methods.

Fabrication of Water Jet Resistant and Thermally Stable Superhydrophobic Surfaces by Spray Coating of Candle Soot Dispersion

A facile synthesis method for highly stable carbon nanoparticle (CNP) dispersion in acetone by incomplete combustion of paraffin candle flame is presented. The synthesized CNP dispersion is the mixture of graphitic and amorphous carbon nanoparticles of the size range of 20–50 nm and manifested the mesoporosity with an average pore size of 7 nm and a BET surface area of 366 m2g−1. As an application of this material, the carbon nanoparticle dispersion was spray coated (spray-based coating) on a glass surface to fabricate superhydrophobic (water contact angle > 150° and sliding angle < 10 °) surfaces. The spray coated surfaces were found to exhibit much improved water jet resistance and thermal stability up to 400 °C compared to the surfaces fabricated from direct candle flame soot deposition (candle-based coating). This study proved that water jet resistant and thermally stable superhydrophobic surfaces can be easily fabricated by simple spray coating of CNP dispersion gathered from incomplete combustion of paraffin candle flame and this technique can be used for different applications with the potential for the large scale fabrication.

Nanocomposites based on esterified colophony and halloysite clay nanotubes as consolidants for waterlogged archaeological woods

We have designed an innovative protocol for the consolidation of waterlogged archaeological woods by using acetone mixtures of halloysite clay nanotubes and a chemically modified colophony (Rosin). Firstly, we have investigated the thermal properties of HNTs/Rosin nanocomposites, which have been prepared by means of the casting method from acetone. The HNTs content have been systematically changed in order to study the influence of the inorganic filler on the thermal stability and glass transition process of Rosin. We have observed that the thermal properties of the hybrids are affected by the specific HNTs/Rosin interactions. Then, acetone dispersions of HNTs/Rosin composites at variable filler content have been employed as consolidants for waterlogged archaeological woods. The quantitative analysis of the thermogravimetric curves have provided the amount of consolidants entrapped into the wood structure. These results have been successfully correlated to the consolidation efficiencies estimated from the analysis of the wood shrinkage volume upon drying. The attained knowledge represents the basic step to develop a green protocol for the long term protection of wooden art-works.

Mechanical response and network characterization of conductive polyaniline/polyacrylamide gels

Electroactive gels based on polyaniline (PANI) and polyacrylamide (PAAm) were prepared by polymerization of aniline in the solution of linear PAAm and subsequent precipitation of PANI/PAAm dispersion in acetone. It has been shown that the composite gels are capable to swelling in water acid and base solutions and dimethyl sulfoxide. It was established by mechanical tests and dynamic oscillatory measurements that the swollen gels demonstrate the elastic response like a covalently crosslinked network but with strong physical interactions between the chains. It is supposed that the observed mechanical elasticity is due to the certain number of elastically effective chemical bonds between PANI and PAAm chains. It is proved that the structure of the samples containing space continuous phase of PANI in the network of PAAm provides them mechanical integrity, good-quality mechanical response, swelling ability and electrical activity.

Study of graphene oxide solid films prepared by Langmuir-Blodgett technology

The preparation of Langmuir ‐ Blodgett (LB) films based on graphene oxide and the study of their structure and optical properties are presented. Graphene oxide dispersions were prepared in different solvents and the stability of each solution was studied. The measurements have shown that most stable dispersions were prepared in tetrahydrofuran, but in acetone, the concentration of graphene oxide is higher. Therefore, graphene oxide monolayers were formed from acetone dispersions. The physicochemical properties of graphene oxide monolayers at the water-air interface were studied. The LB films were deposited onto solid substrates according to Y-type (transfer during downward and upward stroke of substrate) and Z-type transfer (deposition during the upward stroke only). The absorption spectra of graphene oxide LB films exhibit a broad band in the ultraviolet and visible region of the spectrum. The optical density of the film obtained according to the Y-type transfer is greater than the optical density of the film prepared according to the Z-type transfer. The transparency of the films in the visible region of the spectrum is greater than 90 %. As it was shown by SEM images, the films obtained according to the Y-type transfer are more uniform in structure.

Magnetoelectric properties of nickel nanowires-P(VDF–TrFE) composites

Multiferroic composites with very high magnetoelectric coupling composites have been elaborated by incorporating high aspect ratio magnetic nickel particles in a ferroelectric matrix P(VDF–TrFE). Nickel nanowires (NWs) were elaborated by the electrodeposition method which allows obtaining a constant aspect ratio of 250. SEM-FEG images showed a Ni NWs homogeneous dispersion in acetone or in the P(VDF–TrFE). HR-TEM images and electronic diffraction studies revealed that the Ni NWs are monocrystalline, thanks to the electrodeposition method. Magnetic measurements showed a strong anisotropy of the magnetic particles, the coercivity is higher in the parallel direction (160 Oe). This anisotropy decreased for the composites due to the diminution of the Ni NWs interactions. The piezoelectric coefficient obtained after the composite polarization was significant (7 pC N−1) under a polarization field of 60 kV mm−1. The magnetoelectric coefficient reached the value of 237 V/(m Oe) at 4 kHz. According to the previous studies, this value is the highest one found for multiferroic polymer matrix composites.

Physisorption of ionic salts to carbon nanotubes for enhancing dispersion and thermomechanical properties of carbon nanotube-filled epoxy resins

Abstract Cation–π effect on physisorption of aromatic ionic salts to multi-walled carbon nanotube (MWCNT) was demonstrated by the excess adsorption over their pre-ionized aromatic compounds through thermogravimetric analysis. Their adsorption layer on the surface of MWCNT was confirmed by high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. Ionic salt-adsorbing MWCNT showed better dispersion in acetone than pristine and pre-ionized compound-adsorbing MWCNT. Incorporation of 1 wt% ionic salt-adsorbing MWCNT is able to gel the epoxy resin at room temperature according to the rheological study. Based on our proposed model, 1 wt% fully-dispersed MWCNTs are enough to form an interconnected network in epoxy resin resulting in gelation. After crosslinking with amine curing agent, the epoxy nanocomposites incorporating 1 wt% ionic salt-adsorbing MWCNT displayed substantially higher glass and s transition temperatures than that incorporating pristine MWCNT.

Solvent impact on esterification and film formation ability of nanofibrillated cellulose

In this study we have manufactured nanofibrillar cellulose and modified the fibre surface with ester groups in order to hydrophobise the surface. Nanofibrillated cellulose was chosen to demonstrate the phenomena, since due to its high surface area the effects at issue are pronounced. The prepared NFC ester derivatives were butyrate, hexanoate, benzoate, naphtoate, diphenyl acetate, stearate and palmitate. X-ray photoelectron spectroscopy, solid state NMR and contact angle measurements were used to demonstrate the chemical changes taking place on the cellulose surface. NFC ester derivatives can be prepared after a careful solvent exchange to a water-free solvent medium has been carried out. Butyl and palmitoyl esters were chosen for film forming tests due to the difference in their carbon chain lengths, and their contact angles and water vapour and oxygen permeation rates were studied. The prepared nanocellulose esters show increased hydrophobicity even at very low levels of substitution and readily form films when the films are prepared from acetone dispersions. The permeation rates suggest a potential use as barrier materials.

Controlled water adhesion and electrowetting of conducting hydrophobic graphene/carbon nanotubes composite films on engineering materials

Based on the microbumps of graphene nanosheets and the nanostructure of carbon nanotubes (CNTs), novel graphene/CNTs composite films with hierarchical micro- and nanoscale surface roughness were successfully fabricated by simply spraying the mixed acetone dispersion of graphene nanosheets and CNTs onto stainless steel substrates. The as-prepared composite films exhibited controlled surface hydrophobic, adhesive and electrowetting properties via altering the film surface structure and surface energy. Among them the composite film with a 1:5 mass ratio of graphene to CNTs showed high hydrophobicity and conductivity, low water adhesion and contact angle sensitivity to the external electric field, which would help to resolve the surface electrostatic problems and unstable hydrophobicity under applied potential that exist in many conventional insulating hydrophobic materials, and could be useful in some application fields.

Dispersion of C.I. Pigment Violet 23 in acetone using supercritical carbon dioxide

This study investigates the dispersion of 1 wt.% of C.I. Pigment Violet 23 particles in acetone using a supercritical fluid-assisted dispersion process (SFAD) with commercial dispersants. The effects of several key factors on the mean size of pigment dispersoids were investigated. These factors included the formulations of dispersants, the amount of adsorbed dispersants on the surface of pigment particles, and the temperature and pressure during the holding stage in the SFAD process. As evidenced by the experimental results, the isotherm adsorption of dispersoids was well correlated with the Langmuir isotherm model. Increasing the amount of Disperbyk-2150 dispersant adsorbed on the surface of pigment particles and holding the SFAD process at a higher temperature and pressure are both good for improving pigment dispersion in acetone.

Development of carbon conductive additives for advanced lithium ion batteries

The newly developed conductive carbon blacks C-NERGY™ Super C65 and C-NERGY™ Super C45 were studied with regard to their performance as conductive additives in positive lithium ion battery electrodes and compared to other reference conductive carbon blacks. The lowest electrical volume resistivity and highest compressibility were found for C-NERGY™ Super C45 dry-mixed with LiCoO 2 powder. Mixing by high shear forces in acetone dispersion improved the electrical resistivity and compressibility of the C-NERGY™ Super C65 containing LiCoO 2 mixture to the same level obtained for the C-NERGY™ Super C45 mixture in the same process. Acetone dispersions of C-NERGY™ Super C45 and LiCoO 2 showed the lowest viscosities attributed to the carbon black's specific BET surface area of 45 m 2 g −1 being the lowest of all carbon blacks studied. The easy dispersibility of C-NERGY™ Super C45 in LiCoO 2 could be explained by its particular surface group chemistry characterized by time-of-flight secondary ion mass spectrometry. The electrical volume resistivity of the LiCoO 2/carbon black mixtures was in line with the high current rate performance of half-cells with related LiCoO 2 electrodes. Compared to the investigated carbon blacks, the electrical volume resistivity of the graphite conductive additives C-NERGY™ KS6L and C-NERGY™ SFG6L at different concentrations in LiCoO 2 powders showed higher critical volume fractions but lower ultimate resistivity levels. Adding one of these graphites to the carbon black conductive mass improved the electrode density and, at concentrations above the critical volume fraction of the graphite component, significantly decreased the ultimate resistivity level of the LiCoO 2 electrode mass.