Nanoclay Content Research Articles

Eco‐friendly bio‐based composites of cassava starch and natural rubber compatibilized with nanoclays

AbstractBiocomposite films from cassava starch (CS) blended with natural rubber (NR) compatibilized with nanoclay were prepared. Three types of nanoclays, that is, montmorillonite (MMT), kaolinite (KAO) and intercalated kaolinite (DKAO) were used with various content of 2, 4, 6 and 8 wt%, respectively. The mechanical property, water vapor transmission and water solubility of CS/NR composite films were investigated and the interaction of constituents in the CS/NR composites was also characterized by using x‐ray diffraction, Fourier‐transform infrared spectroscopy, scanning electron microscope and dynamic mechanical analysis. The results revealed that the addition of clays considerably improved both the tensile property and water resistance over the pristine starch and CS/NR film. Biocomposite film with 4 wt% of MMT exhibited minimum water vapor transmission and solubility in water content. The tensile strength of CS/NR composites significantly increased while the elongation at break of composites tended to decrease with the increasing nanoclay content. Both mechanical and physical properties were attributed to strong interaction by forming the intercalated structure of MMT and exfoliated structure of DKAO within biocomposites while less interaction was obtained in the case of KAO. The compatibilizing effect of nanoclay in CS/NR composites was also indicated that the glass transition temperature (Tg) of NR or CS‐glycerol phase shifted to higher Tg than that of CS/NR film.

Fabrication of Electrospun Cellulose Acetate/Nanoclay Composites for Pollutant Removal.

The creation of eco-friendly clay-based composites for pollutant removal by adsorption still remains a challenge. This problem might be successfully solved by the development of electrospun polymer-clay composites. For the first time in this study, a one-step fabrication of cellulose acetate (CA) fibers filled with commercially available nanoclays (NCs) was described. The optimal ratio at which CA/NCs dispersions remained stable was accomplished by varying the nanoclay concentration with respect to CA. Furthermore, the selected solvent system and the electrospinning conditions allowed for the successful fabrication of electrospun CA/NC composites. It was found that the composites' surface morphology was not affected by the incorporated nanoclays and was the same as that of the electrospun CA fibers. The performed analyses clearly showed that CA and nanoclays did not react during the electrospinning process. It was found that the distribution of nanoclay layers probably was a mixture of intercalated and exfoliated structures. Notably, the type of the nanoclay strongly influenced the adsorption ability of CA/NC composites toward Cr(VI) ions and MB dye. These results suggested that the fabricated CA/NC composites are suitable for pollutant removal due to their specific structure.

Rheological characterization of ultra-high performance concrete for 3D printing

The authors recently developed a 3D-printable ultra-high performance fiber-reinforced concrete (3DP-UHPFRC) for additive construction of structural members with significantly reduced reliance on steel bars. This study investigates the rheological behavior of the developed 3DP-UHPFRC. The effects of two major factors affecting the performance of 3DP-UHPFRC, namely steel fiber volume (0, 1%, and 2%) and nano-clay (NC) content (0, 0.1%, and 0.2% by binder mass) on workability, static yield stress, dynamic yield stress, and apparent viscosity were determined. Test results showed that the inclusion of steel fibers and NC reduced the workability and led to a significant increase in the static yield stress, dynamic yield stress, and apparent viscosity. However, the effect of NC content on the rheological properties became negligible in the mixtures made with 2% fiber content. Similarly, the effect of steel fiber volume became negligible in the mixtures made with 0.2% NC. In addition, the influence of changes in rheology due to the addition of steel fiber and NC on the extrudability and buildability of the mixtures were investigated by 3D-printing of 500 mm high hollow columns with three different print speeds. The results showed all mixtures exhibited satisfactory extrudability (i.e., no blockage of extruder or tearing of filaments was observed). In addition, the buildability of the mixtures increased as the steel fiber and NC contents increased.

Mechanical Character Analysis of Pineapple Fibre Epoxy Composite with Nanoclay Quantity Variation

Epoxy based hybrid composites are extremely wide used materials in the polymer engineering field and always have a demand for their versatile applications. Nano clay is yet another trending substance handled by many researchers due to their enhanced abrasion characteristics. This research was performed to investigate the effect of dispersing nanoclay into epoxy matrix and further coupled with pineapple fibers to fabricate a hybrid composite of excellent mechanical property. 4 layers of Pineapple fiber mats were compression moulded with epoxy nanoclay blend to obtain composite specimens of 4mm thickness. Nanoclay was added into epoxy resin at four different weight ratios (2%, 4%, 6%, and 8%) to form four different combinations of matrix materials into which pineapple fiber mats were reinforced individually at a constant weight ratio of 25%. The enhancement of mechanical and abrasion rate of the hybrid composites were matched with those of the neat Epoxy/Pineapple fiber composites that are currently being developed as alternatives for brake pads. Moisture absorption rate of the composites were analysed to ASTM D570 and Morphology was inspected using Field Emission Scanning Electron Microscope (FESEM). The results depicted optimum mechanical performance at 4 wt% nanoclay infused epoxy/pineapple fiber composite that had a tensile strength of 166.75 MPa, flexural strength of 801.15 MPa and impact strength of 148.76 kg/sq. m. The least abrasion rate was detected in the composite with 8 wt% nanoclay content, resulting in an abrasion rate of 0.1064 g/m.

A novel method to develop nanocomposite bimodal foams containing expandable polymeric microballoons: microstructural characteristics

This study aims to develop a novel technique in manufacturing nanocomposite bimodal foams containing expandable polymeric microballoons. Low density polyethylene syntactic foams were prepared via injection molding process, afterwards, a batch refoaming method was utilized to create bimodal structure. The effects of microballoon and nanoclay content and foaming time and temperature on microstructure and physical properties of foams were investigated. The results revealed that refoaming leads to a considerable decrease in density due to nucleation of microcells along with re-expansion of microballoons, as well as CO2 diffusion in voids between the matrix and microballoon surfaces. Microballoon content has no significant effect on cell size of bimodal foams, while a great growth in cell density was observed as its content increased. Results also indicated that at low and high foaming temperature and time, melt strength and gas loss are the overcoming phenomena, respectively leading to an optimal processing temperature and time.

Experimental investigation of nano materials applicability in Hot Mix Asphalt (HMA)

• The efficacy of using Nano materials in Hot Mix Asphalt (HMA) was examined. • The effect of CNT and NC, loading frequency and temperature on dynamic modulus and resilient modulus were investigated. • Nano materials (CNT and NC) led to higher stiffness improved Dynamic stability rutting resistance and moisture resistance of HMA. • The optimized percentage of CNT and 1.5% CNT with NC in HMA was determined to be 1.5% and 6%, respectively. • MEP and regression techniques was developed in predicting the dynamic modulus of the nano material modified HMA. Nanotechnology for asphalt modification and incorporating nanomaterials into Hot Mix Asphalt (HMA) to deal with road failure have gained popularity recently. Researchers have reported the improved performance of asphalt modified by nanomaterials but most of the study is limited to binder modification using nanomaterials. The utilization of Nanomaterials in HMA can significantly improve the performance indicators in the form of extension in pavement service life and decrease pavement distresses. The Nanomaterials reinforcement of HMA can enhance pavement performance indicators, including low and high-temperature dynamic modulus and stability and enhancement in rut resistance and stiffness modulus. Nano Materials modified is a suitable solution to improve the mechanical properties of HMA. The current study objectives focus on the experimental investigation of Nano Materials such as Carbon Nano Tubes (CNT) and Nano Clay (NC) applicability in HMA. CNT and NC percentages used in HMA to the weight of bitumen are 0.5%, 1.5%, 2.5% and 2%, 4%, 6%, 8%. Conventional and Nanomaterial modified asphalt mixes were subjected to performance tests such as Simple Performance Tester (SPT), Dynamic Stability and Rutting, Tensile Strength Ratio (TSR), and Resilient Modulus ( M R ) using UTM-25. The present study further aimed to predicting dynamic modulus of nanomaterial modified HMA through Artificial intelligence (AI) modeling using Multi Expression Programming (MEPX) and Regression modelling with validation. Results have indicated that the addition of CNT and NC has improved HMA properties such as enhancement in dynamic modulus and dynamic stability and improves stiffness, rut resistance, and moisture resistance. It has been observed that 1.5% CNT with 6% NC content by weight of bitumen in asphalt mixtures outperformed other CNT and NC percentages. Moreover, Dynamic stability and Rut resistance have been improved by 820% and 64.7%, respectively, while resilient modulus increased by 309% and moisture susceptibility has been reduced by 22.26%. Overall, the asphalt mixtures with 1.5% CNT with 6% NC content has the best results.

To study the Effect of Organophilic Nano-clay on Creep Stiffness of Asphalt Binder at Low Temperatures

Abstract: The asphalt binder must be modified to extend the service life of flexible pavements. As the temperature outside drops, the pavements shrink and develop internal stresses. The pavement may break if this contraction happens quickly enough because it won't have time to relax these stresses. Due to the cracking's orientation with respect to the flow of traffic, this form of fracture is frequently referred to as a "thermal crack" or a "transverse crack.". The purpose of this article is to assess how adding nanoclay to asphalt binder changes its performance at low temperatures. The stiffness and stress relaxation time of a material can be measured with a Bending Beam Rheometer (BBR). It is ideal for asphalt binders to be able to release built-up tensions and not become overly stiff at low temperatures. The BBR test was carried out to investigate the low-temperature behaviour of asphalt binder. Test samples were prepared by adding varying nanoclay content and test temperatures were defined. Three small beams of each percentage were prepared and tested after conditioning at defined test temperatures. Results of modified asphalt binder were assessed and contrasted to unmodified asphalt binder to optimize the nanoclay content. The study revealed that increment in nanoclay amount increased the creep stiffness of asphalt binder. İt was concluded from the study that improvement of creep stiffness played a key role towards the low-temperature performance. The maximum increase in creep stiffness was found by the addition of 5 % nanoclay at -16 °C

Potential improvements in montmorillonite-nanoclay-modified Cold-Mix Asphalt

Over the years, Cold-Mix Asphalts (CMAs) used principally for pothole patching and partial-depth repairs in Ghana have performed abysmally. Given the convenience, environmental friendliness and low cost associated with CMA production, the use of the material in Ghana is likely to continue for a long time to come. Therefore, to justify it continual use in road maintenance, especially pothole patching, the material must be improved in quality considerably beyond what currently pertains to achieve a more successful product. Fillers used in bituminous mixtures have been identified as having the potential to improve mixture properties positively. In view of this, in the quest to improve CMAs, montmorillonite- nanoclay filler (pulverized clay particles of size 1-100 nm) was incorporated in CMAs formulated from five dense gradation regimes adopted from the Asphalt Institute M-19 Specification. The nanoclay filler was added from 1-3% by weight of aggregate at 1% incremental levels. Using the Marshall Mix Design procedure, mixture properties (Stability, Flow, Optimum Bitumen Content and Voids) were accordingly determined. It was observed that when montmorillonite nanoclay was introduced as a filler in the cold mixes, all the gradation groups recorded improvements in their stability at each nanoclay content. At 2% nanoclay content, all the mixtures yielded optimum values. The increase in stability can be attributed partly to the increase in adhesion between bitumen and aggregate and also partly to the possible increase in inter-particle friction occasioned by the presence of the nanoclay particles which add to the rigidity of the compacted matrix. However, on the contrary, flow values increased significantly. In between the nanoclay contents, from 1-2% and 2-3%, average flow increased by 1.8% and 12%, respectively. The same could be said of the Optimum Bitumen Content which increased for all gradation groups when nanoclay was added. The increase in Optimum Bitumen Content can be said to be accountable for the flow increases realized for mixtures with nanoclay. Even though high stability reflects the bitumen binding strength and the internal friction, a benchmark of the interlocking and friction resistance of aggregates, the high flow values observed are also indicative of the potential susceptibility of the cold mixes to rutting deformation, especially at elevated temperatures.

The Elastic Modulus and Damage Stress-Strain Model of Polypropylene Fiber and Nano Clay Modified Lime Treated Soil under Axial Load.

Using polypropylene fiber (PPF) and nano clay modified lime treated soil (LS), the static and dynamic properties of fiber modified lime treated soil (FLS), nano clay modified lime treated soil (NLS), and fiber nano clay composite modified lime treated soil (NFLS) were studied. Through the unconfined compressive strength (UCS) test and dynamic triaxial test of FLS, NLS, and NFLS, the static and dynamic elastic modulus characteristics at 7 day curing age were explored, and the damage stress–strain model was established. The results show that: (1) Polypropylene fiber and nano clay can significantly enhance the mechanical properties of NFLS. Nano clay can promote the reaction between lime and soil to produce calcium silicate hydrate (C-S-H) and calcium aluminate hydrate (C-A-H), thus improving the strength of NFLS, and UCS can be increased by up to 103%. Polypropylene fiber can enhance the ductility of NFLS and increase the residual ductility strength, and the residual strength can be increased by 827%. (2) Nano clay can enhance the static and dynamic elastic modulus of modified lime treated soil. The static and dynamic elastic modulus of NLS, FLS, and NFLS are linear with the change of polypropylene fiber and nano clay content. The static and dynamic elastic modulus of NLS, FLS, and NFLS are linear, exponential, and logarithmic, respectively. (3) The mesoscopic random damage model can characterize the stress–strain relationship of NFLS. Polypropylene fiber and nano clay can improve the ductility and strength of modified LS, and the composite addition of polypropylene fiber and nano clay can improve the ability of modified LS to resist damage.

Direct and Reactive Dyes Recovery in Textile Wastewater Using Calcinated Hydrotalcite

Growing environmental conservation concerns have led researchers to seek the means to treat and recover wastewater. The textile industry dumps vast quantities of wastewater from textile dyes. By means of clays, dye waste can be separated and reused for other industrial processes. Clay absorption varies depending on the type of dye employed because factors like the reactivity of the dye molecule and its size are very important during the absorption process. The absorption capacity of calcined hydrotalcite at several concentrations was compared in a 0.05 g • L-1 solution of four distinct dyes: Direct Blue 199, Direct Red 23, Direct Blue 71 and Reactive Yellow. Dyes have different molecular weights because the weight of reactive dyes is considerably lighter than that of direct dyes, which is why the Lambert-Beer lines of each dye are previously considered. We worked with a 5 g • L-1 clay concentration to introduce the dye into the clay by stirring for 24 h in 100 ml of each dye solution before filtering it and leaving it to dry. In all cases, the dye absorption by nanoclay was nearly absolute and the initial solution was very clean, which are excellent results from the wastewater treatment point of view. Color measurement was performed by a Jasco V-670, double-beam spectrophotometre between 190-2700 nm. Differences in color were calculated and represented in CIE-Lab* color space diagrams. Finally, thermogravimetric (TGA) and X-ray diffraction (XRD) analyses were carried out to ensure both nanoclay-dye interactions and hydrotalcite structure recovery. No large differences were observed under these conditions, which reinforces the idea of using low nanoclay concentrations.

Introducing a new approach to preparing bionanocomposite sponges based on poly(glycerol sebacate urethane) (PGSU) with great interconnectivity and high hydrophilicity properties for application in tissue engineering

In this study, a three-dimensional porous structure of poly(glycerol sebacate urethane) (PGSU) comprising nano-clay and polyacrylic acid (PAAc) was synthesized through a two-step synthesis route. Particulate leaching technique by introducing spun sugar as porogen was also performed as a fabrication method. It was hypothesized that the introduction of spun sugar with its filamentous shape would create interrelated pores required for cell adhesion and proliferation. Polarity, stiffness, and swelling capacity of PGSU would be enhanced by eco-friendly in-situ polymerization of PAAc and the contribution of biocompatible nanoclay. After characterizing the synthesis of PGSU-based scaffolds, viscoelastic behavior, hydrophilicity, and biocompatibility of scaffolds were evaluated. Doubling of swelling capacity in dry state and decrement of water contact angle (WCA) approved the effect of polar carboxyl groups of PAAc in the improvement of polarity and hydrophilicity of PGSU. DMTA results in dry and wet states demonstrated that increasing the concentration of nanoclay and the presence of PAAc chains led to the increase in the storage modulus while the elastic behavior at body temperature was preserved. Eventually, the feasibility of the porous structure of PGSU-based scaffolds in tissue engineering became clear by in vitro biocompatibility test and significant cell adhesion in plasma-treated PGSU/PAAC/nanoclay. Accordingly, introducing clay nanoparticles and in-situ polymerization of acrylic acid, together with porous structure, make PGSU a suitable substrate for cellular interactions.

Characterization of Nano Clay Modified Asphalt Cement

Abstract: In order to enhance the service life of flexible pavements, asphalt binder must be modified. The aim of this research is to compare the physical and mechanical properties of virgin and Nano clay modified asphalt cement. These properties include viscosity values and rutting resistance. Nano clay were incorporated in asphalt binder in various percentages ranging from 3%, 3.5% to 5% of the asphalt weight. The viscosity (Cst) and rutting resistance of the modified asphalt binders were evaluated and compared to an unaltered binder. The addition of Nano clay as a modifier improved the asphalt's properties. The results of the study revealed an increase in viscosity and decrease in binder penetration. Consequently, the viscosity and rutting resistance of the modified asphalts increase with the increase in Nano clay content. While the viscosity and rutting resistance values decrease when the modifier content is increased to 5%. Hence the best improvements in the modified asphalt binders were obtained with 4.5% Nano clay content. Keywords: Organo philic clay, asphalt cement, Hamburg wheel tracker (HWTT), rutting, viscosity, rotational viscometer (RV).

PROPERTIES OF THE WATER-RESISTANT PLYWOOD GLUED WITH PF RESIN WITH THE ADDITION OF TANNIN FILLER AND NANOCLAY

The conducted study was aimed at finding the phenol-formaldehyde adhesive formulation containing both the nanoclay and the tannin filler which allows to manufacture water-resistant plywood characterized by the improved properties. The research assumed the application of six experimental variants having a different proportions of the mentioned components which were compared with the mixture prepared according to the industrial recipe. Properties of liquid mixtures such as their gelation time and viscosity were investigated. Moreover, thedifferential scanning calorimetry (DSC) was performed. The manufactured plywood panels were tested in terms of bonding quality, bending strength and modulus of elasticity. Studies have shown that after the adjustment in components proportions it is possible to achieve the proper viscosity level of adhesive mixtures. The results also indicated that thesuitable amount of nanoclay can contribute to the acceleration of resin gel time, however, the DSC analysis showed no effect on its reactivity. The nanoclay concentrations ranging from 2 to 4 pbw (parts by weight) per 100 g of adhesive positively influenced the bonding quality of plywood. Furthermore, there was no clear tendency in case of the effect of applied formulation on the modulus of elasticity and bending strength of plywood. The mixture containing 3 pbw of nanoclay and 5.3 pbw of tannin filler was distinguished as the most beneficial taking intoaccount the improvement in theproperties of manufactured plywood.

Moisture absorption and spectroscopic studies of epoxy clay nanocomposite

Epoxy resins are prone to serious moisture absorption inspite of their inherent advantages, which can be mitigated by the incorporation of montmorillonite nanoclay that provide tortuous path to flow of moisture. Moisture absorption studies of epoxy clay nanocomposites is carried out, to analyse the effect of nanoclay content, immersion media and immersion temperature. Nanocomposites prepared in 0.5, 1 and 1.5 wt% using magnetic stirring and ultrasonication and neat epoxy specimen were immersed in distilled water and artificial seawater maintained at 28 and 38 °C till saturation. Fick’s and Langmuir’s models were applied to calculate the kinetic parameters from the water absorption graphs. Atomic force microscopy (AFM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope with energy dispersive X-ray (SEM–EDX) characterizations were performed. Diffusivity is least for nanocomposite containing 0.5 wt% nanoclay at both temperatures in both medium. However, it is least when the medium is distilled water. As the temperature of immersion medium increases, the diffusivity also increases. Saturation moisture uptake increased with increase in nanoclay content, because of the residual hydrophilic nature of nanoclay. AFM and XRD analysis revealed better dispersion and exfoliated structure of nanoclay respectively at 0.5 wt% loading. FTIR spectroscopy was applied to identify the chemical bonds that helped in proposing the reaction mechanism of the nanocomposite synthesis. Spectra comparison of dry and wet specimens complimented the moisture absorption data by showing lower infrared transmittance in wet specimens. With Increase in nanoclay content, the transmittance decreased corresponding to increase in saturation moisture uptake for distilled water immersed specimens. SEM–EDX analysis distinguished between the cations entered from the artificial seawater and cations that were still present in the nanoclay.

Effects of Different Ion Erosion on the Hydration Mechanism and Microstructure of Nano-Clay Single-Liquid Grouting Material

The effect of nano-clay (NC) on hydration and microstructure of grouting materials was investigated under different erosion conditions. Six different contents of NC specimens were prepared. This study investigated the effect of NC on the mechanical properties and microstructure of grouting materials under chloride ion erosion and standard curing conditions (SCCs), using ultrasonic pulse velocity (UPV), uniaxial compressive strength (UCS), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The experimental results demonstrated that the nano-core effect can promote the formation of the core reaction of grouting materials and accelerate the hydration process. With the NC increase, the hydration products of ettringite (AFt) and calcium silicate hydrate (C-S-H) also increases. Under chloride ion erosion, it was obtained that when NC was less than 2%, the UCS and UPV were improved. As the NC content is 2%, the hydration reaction is the most appropriate. However, under high humidity conditions, as the NC content is 1%, the amount and density of AFt increased and the formation of C-S-H gel enhanced. The hydration reaction inhibited, and the mechanical properties of grouting materials decreased when NC was further increased. It indicated that the complex underground engineering environment affected the hydration mechanism of nano-grouting materials.

Light Microscopy of Medium-Density Rigid Polyurethane Foams Filled with Nanoclay.

Practical applications and mathematical modelling of the physical and mechanical properties of medium-density rigid polyurethane foams require knowledge of their structure. It is necessary to determine structural characteristics without destroying the foams and measuring each element. A methodology is described for the use of light microscopy on environmentally sustainable, medium-density rigid polyurethane foams (in the density region of ≈210–230 kg/m3), by the analysis of two types of light microscopy images: (1) Cutting surface images; and (2) Through-cutting surface images. The dimensions of structural elements of polyurethane foams, filled with the nanoclay Cloisite-30B at concentrations of 0.0%, 0.25%, 0.50%, 1.0%, 2.0%, 3.0%, and 5.0% from the mass of the filled reacting mixture, are estimated. Probability density functions of projections of bubbles’ diameters and struts’ length are determined using images in three mutually perpendicular planes. A mathematical model is developed for the restoration of the actual dimensions of bubbles’ diameters using data of cutting circles’ diameters. Intercalation and exfoliation of the filler’s Cloisite-30B mono-layers is evaluated via the basal spacing by X-ray diffraction at a 5 wt.% concentration of nanoclay.

Fabrication and characterization of multifunctional nanoclay and TiO2 embedded polyamide electrospun nanofibers and their applications at indoor air filtration

The multifunctional polyamide-6 (PA-6) electrospun nanofibers were fabricated for indoor air filtration. Nanoclay (NC) was used as nanoadsorbent, and TiO2 was preffered as nanocatalyst for photocatalytic oxidation of toluene. The main responses of study were selected as characterization (fiber diameter, tensile strength, air permeability and water vapor transmission) and performance parameters (adsorption and oxidation of toluene). These parameters of nanofibers ranged from 75.8 to 135.9 nm for fiber diameter, 0.51–3.47 MPa for tensile strength, 11.6–19.0 mm/sn for air permeability, 119.9–309.4 g/m2.h for water vapor permeability, 7.0%-43.7% adsorption efficiency at 15 min, and 7.4–12.6% oxidation efficiency at 66 min. The increase in NC content decreased the air permeability values and increased the tensile strength values of nanofibers. The adsorption efficiencies of nanofibers increased from 7% to 28.9, 35.3 and 43.7% with increasing NC ratios (0.0–0.025–0.05–0.5%). The highest CO2 production was obtained for nanofiber having 0.05% of NC and 1% of TiO2 at low UV light energy and short filtration time.

Experimental and modeling studies of the effects of nanoclay on the oil behaviors in a water-sand system.

When oil is released into the oceans, spilled oil may get to the shoreline driven by wind and wave. This study comprehensively explored the effects of bentonite nanoclay on the oil behaviors in a water-sand system from both experimental and modeling perspectives. Four factors including nanoclay concentration, temperature, salinity, and pH have been studied. The increasing nanoclay concentration resulted in the decrease in remaining oil on sand. Higher temperature and salinity were associated with less residual oil on sand in the presence of nanoclay. The lower residual oil on sand with coexisting nanoclay was found to be at pH 7. The factorial analysis results indicated that the nanoclay concentration showed the most significant impact among these factors. Miscibility modeling results showed an increasing temperature was favorable to the nanoclay miscibility. Moreover, the effect of nanoclay on oil behavior was further revealed through the dynamic simulation, in which it can be seen the nanoclay could penetrate into oil droplets and promote the oil detachment from solid substrate. The results of this study can help understand the role of fine particles in the fate and transport of oil on shoreline and support the risk assessment and response planning after oil spill.

Improved water flux in optimized electrospun polysulfone/nanoclay membranes

AbstractWater crisis is undoubtedly one of the main global challenges and water membranes can be used to tackle this issue. In this study, electrospun polysulfone (PSU)/nanoclay membranes were fabricated. The fabrication process was optimized to achieve desirable fibers using response surface methodology, considering nanoclay concentration, electrospinning feeding rate, and voltage as the influencing factors on the membrane properties. SEM images was used to determine the average fiber diameter and imperfection factor of the fibrous composites and their hydrophilicity was assessed based on their water contact angle (CA) values. A suitable model was proposed for each property to predict its variation with the influencing parameters. The results showed that the voltage and feed rate are directly related to the average fiber diameter and CA of the membranes. Moreover, introducing hydrophilic nanoclay to the membranes improved their wettability. The optimum properties were achieved in the membrane containing 5.63 wt% nanoclay, which was electrospun at a feed rate and voltage of 0.7 mL/h, and 16 kV, respectively. Comparing the mechanical properties and water flux performance of pure PSU membranes with the optimal sample confirmed that the presence of nanoclay improved the mechanical strength and toughness of the membranes and enhanced the attainable water flux.

Unconfined Compressive Strength and Splitting Tensile Strength of Lime Soil Modified by Nano Clay and Polypropylene Fiber

Here we study the effects of nano clay and polypropylene fiber on the unconfined compression and splitting properties of lime soil. Through a series of unconfined compressive strength (UCS) tests and splitting strength (STS) tests, the mechanical properties of lime soil (LS), nano clay modified lime soil (NLS), fiber modified lime soil (FLS), nano clay and fiber composite modified lime soil (NFLS) are analyzed, and the volume calculation formula of each phase in NFLS is deduced. Nano clay content αn, porosity volume η and lime volume LVi as independent variables, and the prediction models of UCS and STS of NFLS were established. Furthermore, the microstructure of LS, NLS, FLS and NFLS was analyzed by scanning electron microscope (SEM). It can be concluded that (1) with the increase in nano clay content, the UCS and STS of LS and FLS gradually increase. With the increase in fiber content, the UCS of LS first increases and then decreases, while the UCS and STS of NLS and STS of LS increase with the increase in fiber content, and the optimal fiber content is 0.75%. (2) UCS and STS of NFLS and η/LVi meet the linear relationship. The empirical formulas of UCS and STS established in this paper have a prediction accuracy of less than 10%. The strength of NFLS can be predicted according to the dry density of the sample and the content of each component material. (3) Nano clay can fill the pores of LS and promote the pozzolanic reaction between lime and soil, while fiber mainly plays a reinforcing role in LS, so as to improve the UCS and STS of LS. In NFLS, nano clay can improve the interfacial properties between fiber and LS, so as to improve its UCS and STS. This study can provide a reference for the modification technology of lime soil.