Stearyl Trimethyl Ammonium Research Articles

Effects of modified palygorskite on performance, crystallization and rheology of polyphenylene sulfide

In this work, Pal-Fe3O4 was prepared by magnetic modification of purified palygorskite (Pal), and then STAC@Pal-Fe3O4 was prepared by organic modification of Pal-Fe3O4 with Stearyl trimethyl ammonium chloride (STAC). The preparation conditions of STAC@Pal-Fe3O4 were optimized by orthogonal experiment. Some characterization results such as X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) showed that palygorskite had been successfully modified. In addition, STAC@Pal-Fe3O4/polyphenylene sulfide (PPS) nanocomposites were prepared by melt blending method. The mechanical properties, rheological properties and crystallization properties of STAC@Pal-Fe3O4/PPS nanocomposites were studied. When the mass fraction of STAC@Pal-Fe3O4 in PPS was 2.5 wt%, the tensile strength and impact strength of STAC@Pal-Fe3O4/PPS nanocomposites were 65.06% and 366% higher than those of pure PPS, respectively. Thermogravimetric analysis showed that STAC@Pal-Fe3O4 improved the thermal stability of PPS. The non-isothermal crystallization behavior of STAC@Pal-Fe3O4/PPS nanocomposites was studied by DSC method and Rheonaut technology for simultaneous rheology and FTIR, respectively. The results showed that STAC@Pal-Fe3O4 can significantly improve the crystallization rate and crystallinity of PPS. Rheological studies presented that STAC@Pal-Fe3O4 had strong compatibility with PPS.

Application of Surface-Modified Nanoclay in a Hybrid Adsorption-Ultrafiltration Process for Enhanced Nitrite Ions Removal: Chemometric Approach vs. Machine Learning

Herein, we report the results of a study on combining adsorption and ultrafiltration in a single-stage process to remove nitrite ions from contaminated water. As adsorbent, a surface-modified nanoclay was employed (i.e., Nanomer® I.28E, containing 25-30 wt. % trimethyl stearyl ammonium). Ultrafiltration experiments were conducted using porous polymeric membranes (Ultracel® 10 kDa). The hybrid process of adsorption-ultrafiltration was modeled and optimized using three computational tools: (1) response surface methodology (RSM), (2) artificial neural network (ANN), and (3) support vector machine (SVM). The optimal conditions provided by machine learning (SVM) were found to be the best, revealing a rejection efficiency of 86.3% and an initial flux of permeate of 185 LMH for a moderate dose of the nanoclay (0.674% w/v). Likewise, a new and more retentive membrane (based on PVDF-HFP copolymer and halloysite (HS) inorganic nanotubes) was produced by the phase-inversion method, characterized by SEM, EDX, AFM, and FTIR techniques, and then tested under optimal conditions. This new composite membrane (PVDF-HFP/HS) with a thickness of 112 μm and a porosity of 75.32% unveiled an enhanced rejection efficiency (95.0%) and a lower initial flux of permeate (28 LMH). Moreover, molecular docking simulations disclosed the intermolecular interactions between nitrite ions and the functional moiety of the organonanoclay.

The effect of quaternary ammonium salts with different chain lengths on copper filling behavior in blind holes of printed circuit board

The rapid and defect free blind hole copper super filling is the key technology to ensure the quality and development of printed circuit boards (PCBs). The linear quaternary ammonium compounds with a low molecular weight are expected to act as a potential suppressor for blind hole copper filling. Here, three quaternary ammonium salts with different molecular chain lengths (the dodecyl trimethyl ammonium chloride, the cetyl trimethyl ammonium chloride and the stearyl trimethyl ammonium chloride) were selected to study the effects of the molecular chain length of quaternary ammonium salt on the copper filling behavior of the PCB blind holes. The electrochemical results show that the three quaternary ammonium salts show greater inhibition ability on copper deposition compared with the traditional additives (polyethylene glycol (PEG) and Cl−) and furthermore, the suppressor effect becomes stronger with the increase of molecular weight. The blind hole copper filling experiment of PCB is also carried out to study the copper filling capacity of three quaternary ammonium salts. The filling experiment reveals that compared with the traditional suppressors (PEG and Cl−), the filling quality of blind hole copper is significantly improved when the three quaternary ammonium salts are used as suppressors. Moreover, under the coordination of accelerator (bis (3-sulfopropyl) disulfide (SPS)), the three quaternary ammonium salts can realize more rapid copper super filling without chloride ion in the electrolyte. Cross-section and surface morphological analysis further illuminates that the quaternary ammonium salt as an suppressor can also more effectively inhibit the deposition of copper on the PCB surface and reduce the roughness of the copper layer. The present results imply that quaternary ammonium salts have greater advantages for copper filling and are expected to replace traditional suppressors as new suppressors.

Tuning redox ability of Zn3In2S6 with surfactant modification for highly efficient and selective photocatalytic C-C coupling

Heterogeneous photocatalytic C-C coupling is a green and efficient approach to producing valuable chemicals. The strategies for guiding effective photocatalyst design are desired but still limited. Here, we report visible-light-driven highly selective photocatalytic C-C coupling of benzyl alcohol over surfactant-modified Zn3In2S6 semiconductors. A complete switch of product selectivity from benzyl aldehyde (91.5 %) to C-C coupling products (96.5 %) is obtained by the modification of Zn3In2S6 with stearyl trimethyl ammonium bromide (STAB). This modification assists the formation of sulfur vacancies on Zn3In2S6 to enhance charge carrier separation, thereby increasing the photocatalytic activity. The selectivity switch is mainly attributed to increasing conduction band position of Zn3In2S6 by surfactant modification which strengthens the reduction ability of photogenerated electrons to induce the reversible reduction of benzyl aldehyde to ketyl radicals, and partially to the poor oxidation ability of the material that inhibits the oxidation of ketyl radicals to benzyl aldehyde. Encouragingly, this universal protocol has been successfully applied to a series of aromatic alcohols and biomass-derived furanic alcohols to selectively produce C-C coupling products.

Polyhydroxybutyrate-Based Nanocomposites for Bone Tissue Engineering.

Bone-related diseases have been increasing worldwide, and several nanocomposites have been used to treat them. Among several nanocomposites, polyhydroxybutyrate (PHB)-based nanocomposites are widely used in drug delivery and tissue engineering due to their excellent biocompatibility and biodegradability. However, PHB use in bone tissue engineering is limited due to its inadequate physicochemical and mechanical properties. In the present work, we synthesized PHB-based nanocomposites using a nanoblend and nano-clay with modified montmorillonite (MMT) as a filler. MMT was modified using trimethyl stearyl ammonium (TMSA). Nanoblend and nano-clay were fabricated using the solvent-casting technique. Inspection of the composite structure revealed that the basal spacing of the polymeric matrix material was significantly altered depending on the loading percentage of organically modified montmorillonite (OMMT) nano-clay. The PHB/OMMT nanocomposite displayed enhanced thermal stability and upper working temperature upon heating as compared to the pristine polymer. The dispersed (OMMT) nano-clay assisted in the formation of pores on the surface of the polymer. The pore size was proportional to the weight percentage of OMMT. Further morphological analysis of these blends was carried out through FESEM. The obtained nanocomposites exhibited augmented properties over neat PHB and could have an abundance of applications in the industry and medicinal sectors. In particular, improved porosity, non-immunogenic nature, and strong biocompatibility suggest their effective application in bone tissue engineering. Thus, PHB/OMMT nanocomposites are a promising candidate for 3D organ printing, lab-on-a-chip scaffold engineering, and bone tissue engineering.

Sensitive analytical detection of nitrite using an electrochemical sensor with STAB-functionalized Nb2C@MWCNTs for signal amplification

An electrochemical sensor based on stearyl trimethyl ammonium bromide - functionalized niobium carbide@multi-walled carbon nanotubes (Nb2C@MWCNTs-STAB) for signal amplification was successfully constructed for sensitive detection of nitrite (NO2−). Niobium carbide@multi-walled carbon nanotubes (Nb2C@MWCNTs) with high electrical conductivity and water dispersibility were first prepared in a one-pot hydrothermal synthesis, after which cationic STAB was added to overcome the negative surface charge on the Nb2C@MWCNTs. The electrostatic attraction between Nb2C@MWCNTs-STAB and NO2− was improved by the STAB, which enhanced the sensitivity of the constructed sensor for NO2−. Under optimized conditions, Nb2C@MWCNTs-STAB/GCE exhibited excellent analytical performance for detection NO2− with two wide liner ranges (0.1–100 μmol L−1 and 100–2000 μmol L−1) and a limit of detection of 0.022 μmol L−1. Nitrite recovery tests in milk and spinach samples showed recoveries in the range of 89.82–104.52%. The NO2− residues in ham and pickled vegetable (cedrela sinensis) samples were analysed using the presented sensor and a spectrophotometric method, with no significant difference found between the results of the two methods.

Pharmaceuticals Removal by Adsorption with Montmorillonite Nanoclay.

The problem of purifying domestic and hospital wastewater from pharmaceutical compounds is becoming more and more urgent every year, because of the continuous accumulation of chemical pollutants in the environment and the limited availability of freshwater resources. Clay adsorbents have been repeatedly proposed as adsorbents for treatment purposes, but natural clays are hydrophilic and can be inefficient for catching hydrophobic pharmaceuticals. In this paper, a comparison of adsorption properties of pristine montmorillonite (MMT) and montmorillonite modified with stearyl trimethyl ammonium (hydrophobic MMT-STA) towards carbamazepine, ibuprofen, and paracetamol pharmaceuticals was performed. The efficiency of adsorption was investigated under varying solution pH, temperature, contact time, initial concentration of pharmaceuticals, and adsorbate/adsorbent mass ratio. MMT-STA was better than pristine MMT at removing all the pharmaceuticals studied. The adsorption capacity of hydrophobic montmorillonite to pharmaceuticals decreased in the following order: carbamazepine (97%) > ibuprofen (95%) > paracetamol (63–67%). Adsorption isotherms were best described by Freundlich model. Within the pharmaceutical concentration range of 10–50 µg/mL, the most optimal mass ratio of adsorbates to adsorbents was 1:300, pH 6, and a temperature of 25 °C. Thus, MMT-STA could be used as an efficient adsorbent for deconta×ating water of carbamazepine, ibuprofen, and paracetamol.

Molecular interaction for quasi-binary mixture of N-acyl amino sulfonate amphoteric surfactant from castor oil and stearyltrimethyl ammonium bromide

The micellization behavior and the molecular interaction of quasi-binary mixture constituted by an amphoteric sodium N-acyl amino sulfonate based on castor oil (AAS-CO) with a cationic stearyltrimethyl ammonium bromide (STAB) in aqueous solution at 298.15 K were investigated using both the tensiometry and the conductometry and the two techniques were adopted to determine the mixed critical micelle concentration (cmc). Based on the regular solution theory and in the framework of the pseudophase separation model, Rubingh’s model and Clint’s model were adopted to estimate the mole fractions and the activity coefficients in mixed micelle, the interaction parameters between quasi-one AAS-CO and STAB. Also, thermodynamic parameters were obtained by thermodynamic models. Synergistic interaction between surfactants and non-ideal mixing were observed in the entire range of composition in this investigation. The addition of quasi-one AAS-CO into aqueous solution can induce the alteration of interaction behavior between surfactants, which can be explained rationally by the shielding effect, the electrostatic repulsion and the steric hindrance. Thermodynamic parameters imply that it appears an enthalpically spontaneous behavior in the process of micellization and there exists a largest negative deviation of free energy change of micellization from the ideal case at the optimum composition in which a maximum synergism happens. These findings will help with understanding the molecular interaction between quasi-one component and other one in surfactant mixtures.

Morphological and Chemical Analysis of Low-Density Polyethylene Crystallized on Carbon and Clay Nanofillers.

Interest in carbon and clay-based nanofillers has grown in recent years. The crystallization behavior of low-density polyethylene (LDPE) was studied using a variety of notable nanofillers used in engineering applications and prepared using a solution crystallization method. Carbon nanotubes (CNTs), graphene oxide nano-platelets, clay (montmorillonite), and modified clay (surface-modified with trimethyl stearyl ammonium) were used to induce heterogeneous crystallization of LDPE. The crystallized LDPE samples, imaged using scanning and transmission electron microscopy, revealed different microstructures for each nanohybrid system, indicating these various nanofillers induce LDPE lamellae ordering. The underlying interactions between polymer and nanofiller were investigated using FTIR spectroscopy. X-ray diffraction (XRD) was used to determine crystallinity. This work examines how the differences in morphology and chemical structure of the nanofillers induce changes in the nucleation and growth of polymer crystals. These results will provide guidance on functional design of nano-devices with controlled properties.

Regeneration of Spent Bleaching Earth for PLA Nanocomposite Filler

This paper concerns on regeneration of spent bleaching earth (SBE) as a filler in biodegradable nanocomposite. The nanocomposite were produced from two different production methods, solvent casting and extrusion. SBE can be used as filler after being regenerated by removing oil and impurities. A regeneration method for SBE was conducted using chemical treatment. Regeneration process was proved to be succesful as shown in FTIR with the absence of peak at 2850 cm—1 – 2930 cm−1 and 1730 cm−1 indicating the disappearance of free fatty acids and ester bonds from regenerated bleaching earth (RBE). The RBE was then applied as filler for PLA-Nanocomposite, biodegradable plastic, a suitable substitute for conventional plastic. The production of nanocomposite used two different surfactants, namely octadecyl amine (ODA) and trimethyl stearyl ammonium chloride (TSC) at two different concentration (20 mmol and 40 mmol). The mechanical property of PLA-Bentonite nanocomposite was then analyzed for tensile strength and permeability. The highest tensile strength and lowest gas permeability was obtained by nanocomposite that used 40 mmol TSC as surfactant, with 12.48 MPa and 0.017 g/day, respectively. Moreover, addition of regenerated bleaching earth to PLA-Nanocomposite during production using extrusion and solvent casting had slight different effect. XRD pattern of all extruded PLA-nanocomposite samples indicated the formation of exfoliated structure, as shown in XRD pattern with very low intensity peak around 2 nm at 2? = 5, while only a few of samples of PLA-nanocomposite created by solvent casting indicating the same structure.

Effect of Modified Nanoclay Surface Supported Nickel Catalyst on Carbon Dioxide Reforming of Methane

The activity and stability of modified nanoclays surface supported nickel (Ni/NC-x) catalyst were investigated and compared to unmodified nanoclay surface supported nickel (Ni/NC) catalyst in dry reforming reaction (500–800 °C). The nickel metal was loaded on modified nanoclay surface with different alkylammonium modifiers—trimethylstearyl ammonium (NC-T), methyl dihydroxy-ethyl hydrogenated tallow ammonium (NC-M), aminopropyltriethoxysilane and octadecylamine (NC-A), and dimethyl dialkyl amine (NC-D) by using the impregnation method. As a results, the surface area and pore volume of Ni/NC-x catalysts were 1.70–3.96 and 2.33–4.33 times higher than that of Ni/NC catalyst, respectively. A longer chain of alkylammonium ions of modifier enhanced the intercalation of the modifier molecules into the interlayer of the nanoclay. Among these catalysts, the highest surface area of Ni/NC-T catalyst could facilitate the Ni metal dispersion and smaller size of NiO, resulting in the stronger interaction between Ni and NC-T support. It then gave the highest CO2 and CH4 conversions and H2/CO ratio. In addition, H2 and CO yields of Ni/NC-T catalyst were 1.21 and 1.20 times higher than that of Ni/NC catalyst, respectively. Moreover, the modified nanoclays surface supported nickel catalyst could reduce the carbon formation during the reaction.

Reinforcement of the two-stage leaching of laterite ores using surfactants

A two-stage leaching process, namely, high-pressure acid leaching-atmospheric acid leaching, was used to treat laterite ores under mild conditions. The leaching ratio of Ni was low because of adsorption and incomplete leaching. In this work, surfactants were used as additives to boost the leaching ratio of Ni. The effect of surfactant type (cationic, anionic, and nonionic surfactants) on the leaching ratio of Ni was investigated. Leaching results showed that stearyl trimethyl ammonium chloride (STAC) apparently increased the leaching ratios of valuable metals. The variation in the physicochemical properties of the lixiviant and the residue improved the leaching ratio of Ni in the presence of STAC. Kinetics analysis indicated that the leaching process was controlled by chemical reaction.

Interaction between STAC and coal/kaolinite in tailing dewatering: An experimental and molecular-simulation study

The presence of clay minerals in coal tailings leads to a significant deterioration during the dewatering process. In this study, a cationic surfactant, stearyl trimethyl ammonium chloride (STAC), was considered to enhance the dewatering efficiency of coal tailings. The effect of STAC on coal tailing dewatering was evaluated by the filtration test. Results indicate that STAC can reduce filter cake moisture by increasing the hydrophobicity of particles, decreasing the surface tension of the filtrate, as well as neutralizing the associated charge. Furthermore, to investigate the interactions between STAC and coal tailings, the morphology of adsorbed STAC, interfacial adsorption structure, and dynamic behavior of water molecules were determined by atomic force microscopy (AFM) and molecular dynamics (MD) simulations on an atomic scale. AFM results revealed that the morphologies of STAC adsorbed on coal and kaolinite surfaces differed, owing to distinct interaction mechanisms. The adsorption of STAC on the kaolinite 001 surface is more uniform than on the 001- face and is predominantly based on monolayer adsorption through electrostatic interactions and hydrogen bonding. The MD simulation results suggest that the adsorption of STAC significantly inhibits the attachment of water molecules on coal and kaolinite surfaces. The nitrogen atoms of STAC were adsorbed to the particle surface, such that its alkyl chains were oriented towards water, thereby weakening the interaction between the particles and water. The above findings indicate that the addition of STAC can improve the hydrophobicity of coal and kaolinite effectively and thus, enhance the dewatering performance of coal tailings.

TEÑIDO DE LANA POR AGOTAMIENTO CON NANOARCILLAS Y EXTRACTOS DE ACHIOTE (BIXA ORELLANA)

Nanotechnology is used to generate new nanometric structures. The objective of this research was to develop the formation of a nanopigment using the carotenoid dyes from Achiote (Bixa Orellana) to optimize molecular compaction in 100% wool tissue. For the formation of the nanopigment, 10g of nanoclays were used: Trimethyl stearyl ammonium or Montmorillonite, K10, Halloysite and Bentonite hydrated separately in 2L of deionized water. The concentration was 0.005 g / L; then, with the achiote extracts previously separated with sodium and potassium hydroxide, a solution of 10g of solid pigment and 10g of liquid dye was made separately in 1L of demineralized water: the concentration was 0.01 g / L. The mixing for the cationic exchange between the nanoclay and the pigment is carried out at a ratio of ¼, that is, 100 ml of nanoclay in 400 ml of solid pigment. The same was done with the liquid dye; With the nanopigment formed, 17 wool tissue samples were dyed. The method used is the experimental one; the analysis used color measurement with a spectrophotometer; fastness to washing, loading and unloading to rubbing is assessed; the ultraviolet protection factor UPF of the tissue is evaluated. The Cie94 Delta-E color fastness shows significant color changes. Regarding washing and rubbing, they show differences mostly on a 5/4 scale (excellent / very good) and minimal (between medium / low) 3/2; In addition, the results of the UV-Visible Spectrophotometry measurements of the UVA sun protection factor were low in wool, therefore it was concluded that it has greater protection from ultraviolet rays: this could represent less damage to the skin.

Variasi Jarak Antar Layer Bentonit Pada Pembuatan Nanokomposit Pla-Bentonit Sebagai Kemasan Makanan

In this study, bentonite was used as a filler in the synthesis of polylactic acid (PLA) nanocomposite. The mechanical property of PLA-Bentonite nanocomposite was treated using two different surfactants, namely octadecyl amine (ODA) and trimethyl stearyl ammonium chloride (TSC) at two different concentration (20 mmol and 40 mmol). The treatments of ODA and TSC in the matrix with regards to the basal spacing of bentonite stacks measured by X-Ray Diffraction (XRD) analysis. The results showed a significant increase in basal spacing was obtained when TSC 40 was applied for treatment. Data of Fourier Transform Infrared Spectroscopy (FTIR) suggested that this increase was caused by the incorporation of surfactant into the bentonite stacks. Most of the PLA-Bentonite nanocomposite can form intercalation structure, while a sample containing TSC 40 formed exfoliation structure. This exfoliation structure resulted in a film with the best tensile strength and water vapor permeability compared to the others. The film containing TSC 40 showed the lowest reduction in water activity, almost similar to the bread sample wrapped using conventional plastic. The bread wrapped with TSC 40 film was not grown by fungi as opposed to the conventional plastic, showing the potential of the nanocomposite film as food packaging.

Effect of Emulsifier on the Structure and Properties of Waterborne Silicone Antifouling Coating

Three-component waterborne silicone antifouling coatings, which could cured at room temperature, were prepared, respectively, with cationic (stearyl trimethyl ammonium bromide) or anionic (sodium dodecyl benzene sulfonate) silicone emulsion as a film-forming substance, γ-methacryloxypropyltrimethoxysilane as a curing agent and dibutyltin dilaurate as a catalyst. The effect of emulsifier on the structure and properties of silicone coating was studied. The results showed that the coating with cationic silicone emulsion had high crosslinking density, and its surface is smooth. The surface of the coating prepared by the anionic silicone emulsion is rough. Emulsifier type had no obvious effect on the surface free energy of the waterborne silicone coating. The coatings have the characteristics of low surface energy and excellent bacterial desorption properties. Stearyl trimethyl ammonium bromide in the cured coating can reduce the adhesion of marine bacteria on the coating surface. Both the emulsifiers can inhibit the activity of Navicula Tenera. The waterborne silicone coating prepared by cationic silicone emulsion has better comprehensive mechanical properties and antifouling performance.

Study of STAB- and DDAB-modified sepiolite tructures and their adsorption performance for emulsified oil in produced water

Electrostatic adsorption and hydrophobicity constitute the main functions of effective removal of emulsified oils (EOs) in produced water. Here, sepiolite (Sep) is modified with single-chain and double-chain organic cation surfactants, stearyl trimethyl ammonium bromide (STAB) and dimethyl dioctadecyl ammonium bromide (DDAB). Analyses of SEM, CA and ζ-potential indicated that individually-dispersed Sep fibers modified to form Sep fibrous aggregates with a more hydrophobic and electropositive surface, which greatly improved EOs adsorption and oil-water separation efficiency, and EOs removal efficiency exceeded 99%. The maximum adsorption capacities were 957.0 mg/g for STAB-Sep and 1031.5 mg/g for DDAB-Sep, suggesting that modified Sep with double chains exhibited a high affinity for EOs. Both the Langmuir and the Freundlich isotherms could be used to explain the adsorption process. Thermodynamic parameters proved that the adsorption process was a spontaneous endothermic physical process. This study provides a theoretical foundation for the design of high-efficiency and low-cost organoclay adsorbents.

Viscoelastic surfactant fracturing fluids for use in coal seams: Effects of surfactant composition and formulation

Recently, viscoelastic surfactant (VES) fracturing fluids have attracted wide attention because they are highly viscoelastic and environmentally benign. To optimize fracturing fluid formulations for coal reservoir conditions, 135 groups of VES fracturing fluids were prepared. The influence of the cationic surfactant’s hydrocarbon chain lengths on water loss, wettability, viscosity, and temperature resistance were analyzed. To further improve the surfactant’s aggregation capabilities, zwitterionic surfactants were added to fracturing fluids prepared with stearyl trimethyl ammonium chloride (STAC). We found that STAC can reduce water loss more effectively during fracturing than the cationic surfactant hexadecyl trimethyl ammonium chloride (CTAC). Appropriate amounts of cocoamidopropyl betaine (CAB) increased the viscosity and temperature resistance of the fracturing fluid. It is important to note that as the concentration of sodium salicylate (NaSal) increases, the maximum viscosity of VES fracturing fluid with CAB added is twice that of a fracturing fluid without CAB.

METHANE DRY REFORMING OVER MONTMORILLONITE SURFACE MODIFICATION SUPPORTED NICKEL CATALYST

Dry reforming of methane has been taken an interest in research and development for converting greenhouse gases (CH4 and CO2) into hydrogen (H2) and carbon monoxide (CO). Clay has been considered as promising materials because of their structure, low cost and wide availability. Different surface modifications of clay directly affect the performance of catalyst in term of CH4 and CO2 conversion. This research studied nickel loaded on montmorillonite (MMT) clay support with different surface modifications on the activity in dry reforming of methane in fixed-bed reactor with reactant gases flow rate of 60 ml/min (CH4:CO2 of 1) at reaction temperature ranges of 500 – 800°C. Montmorillonite clay support with different surface modifications including trimethyl stearyl ammonium (MMT-TSA), dimethyl dialkyl amine (MMT-DDA), methyl dihydroxy-ethyl hydrogenated tallow ammonium (MMT-MDA) and aminopropyltriethoxysilan and octadecylamine (MMT-AO) were investigated. As the results, the performances of all catalysts increased with increasing reaction temperature because this reaction is endothermic reaction. Among them, Ni/MMT-TSA catalyst exhibited the highest CH4 and CO2 conversions at all reaction temperatures due to its high surface area, and high metallic surface area.

Evaluating the effect of organic reagents on short-term aging resistance of the organic rectorite asphalt by multi-indicators

The structure of organic reagents has an effect on the properties of the OREC modified asphalt. This study selected dodecyl trimethyl ammonium chloride (1231), lauryl dimethyl benzyl ammonium chloride (1227) and stearyl trimethyl ammonium chloride (1831) to modify Na-rectorite (Na-REC) and then prepared OREC modified asphalts. The objective is to evaluate the effect of organic reagents on short-term aging resistance of the OREC modified asphalt. Physical properties, rheological properties and FTIR tests were conducted. Results indicate that the introduction of Na-REC and ORECs improves the short-term aging resistance of base asphalt, and organic modifications to Na-REC have better effect. 1831-reagent endows OREC with the strongest restriction on oxygen penetration and then leads to the best short-term aging resistance of OREC modified asphalt, followed by 1227-reagent, 1231-reagent. Aging sensitivities shown by various rheological indices were compared. The result demonstrates that the complex modulus aging index and RAI (rutting resistance factor aging index) are most sensitive to rolling thin film oven aging, followed by VAI (viscosity aging index), phase angle aging index. Moreover, the atomic force microscope (AFM) was employed to evaluate the microstructure of asphalt samples. The result demonstrates that there is some absorption of Na-REC and ORECs to asphaltene, and ORECs probably hinder the transformation of asphalt from some lightweight compounds to asphaltenes more effectively than Na-REC during RTFO aging.