Influence of the nonionic surfactants’ nature on the structures and properties of organo-montmorillonites

Preparation and Characterization of TCPP-CaMMT Nanocompound and Its Composite with Polypropylene

Based on the molecular dynamics method, the tris-(1-chloropropan-2yl) phosphate (TCPP)/montmorillonite (MMT) molecular model was established to study the binding energy and microstructure changes in TCPP and MMT. The theoretical simulation results showed that TCPP can enter the MMT layer and increase the layer spacing. From this, an organic intercalated Ca-montmorillonite TCPP-CaMMT was prepared by a very simple direct mixing method using flame retardant TCPP as a modifier. Polypropylene (PP) composites were prepared by TCPP, CaMMT, and TCPP-CaMMT. The microstructures of TCPP-CaMMT nanocompounds and PP composites were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results showed that TCPP-CaMMT nanocompounds could be exfoliated into nanosheets in PP. The flame retardancy and mechanical properties of PP/TCPP-CaMMT samples were studied by limited oxygen index (LOI) measurements and tensile tests. The PP/TCPP-CaMMT composites showed better LOI, tensile strength, and elongation at break than the machine-mixed PP/TCPP + CaMMT.

Preparation of Intercalated Organic Montmorillonite DOPO-MMT by Melting Method and Its Effect on Flame Retardancy to Epoxy Resin

An intercalated organic montmorillonite DOPO-MMT was prepared through the melting method using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as a modifier. Epoxy resin (EP) composites were prepared with DOPO-MMT, DOPO, MMT, and the physical mixtures of DOPO+MMT as flame retardants. The microstructure of the flame retardants and EP samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The flame retardant properties, thermal stability, and residual char structure of the EPs were studied by the limited oxygen index (LOI) test, the UL-94 vertical burning test, thermogravimetric analysis (TGA), the differential scanning calorimeter (DSC) test, the cone calorimeter (CONE) test as well as other characterization methods. The results showed that the intercalated organic montmorillonite DOPO-MMT can be successfully prepared by the melting method and that the MMT is evenly dispersed in the EP/DOPO-MMT composite in the form of nanosheets. The EP/DOPO-MMT nanocomposites showed the optimal flame retardancy (LOI, UL-94, PHRR, etc.) among the EPs with DOPO, MMT, and the physical mixture of DOPO+MMT. The flame-retardant grade of the material reached V-0.

Modification of Bentonite with Cationic and Nonionic Surfactants: Structural and Textural Features

Surfactant-modified clay minerals are known for their good sorption properties of both organic and inorganic compounds from aqueous solutions. However, the current knowledge regarding the effect of both cationic and nonionic surfactants on the properties of bentonite is still insufficient. Bentonite, with montmorillonite as the base clay, was modified with hexadecethyltrimethylammonium bromide (a cationic surfactant) in the amount of 1.0 cation exchange capacity (CEC) of bentonite and varying concentrations of t-octylphenoxypolyethoxyethanol (Triton X-100, a nonionic surfactant). We aimed to improve the understanding of the effect of nonionic and cationic surfactants on clay minerals. The modified bentonites were characterized by X-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TG/DTA), Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (SEM) and specific surface area and pore volume (BET). According to our results, the presence of a cationic surfactant significantly increased the amount of the adsorbed nonionic surfactant. Moreover, an increase in the concentration of nonionic surfactants is also associated with an increase in the effectiveness of the modification process. Our results indicate that the amount of nonionic surfactant used has a significant effect on the properties of the obtained hybrid material. Modification of bentonite with a nonionic surfactant did not cause an expansion of the interlayer space of smectite, regardless of the presence of a cationic surfactant. The modification process was found to significantly decrease the specific surface area of bentonite. Improvement of hydrophobic properties and thermal stability was also observed.

Separation Emulsion via Non-Ionic Surfactant: An Optimization

Achieving emulsion stability in the petroleum industry is a major challenge due to several problems encountered in the oil refining process, such as corrosion in equipment, high-pressure drops in pipelines, and catalyst poisoning in upstream facilities. Thus, several methods are applied for emulsion treatment and chemical treatment using surface-active agents, a fundamental method in the petroleum industry. The present work investigated the performance of a non-ionic surfactant in separating water in a crude oil emulsion via the bottle test technique. Then, a Fractional Factorial Design (2K−1) was used to characterise the effect of significant variables. In particular, a Pareto chart was employed and factors such as demulsifier dosage, toluene concentration, pressure, sitting time, and temperature were investigated. Accordingly, the parameters applied were further analysed using a Central Composite Design (CCD) based on the Response Surface Method (RSM). The experimental results based on analysis of Variance (ANOVA) show that demulsifier dosage, temperature, and sedimentation times were the main variables affecting the dehydration process, with the highest F-values being 564.74, 94.53 and 78.65 respectively. The increase in the surfactant dosage before critical concentration, temperature and sitting time leads to boosting dehydration efficiency. In addition, a mathematical model was established for the variables, with a coefficient of determination value of 0.9688. Finally, numerical optimisation was performed on the variables and the results show that the optimal values are 1000 ppm, 15.5 mL, −400 mmHg, 120 min, and 90 °C, for demulsifier dosage, toluene concentration, pressure, sitting time, and temperature, respectively.