Organoclay Research Articles

Property Investigation of Poly (Ethylene Co-vinyl Acetate)/Poly (l-Lactic Acid)/Organo Clay Nanocomposites

In this study, EVAc/PLA/organo clay nanocomposites were prepared via solution mixing method. The SEM images were used to investigate the morphology of nanocomposites revealing no phase separation or agglomeration of disperse phase in EVAc/PLA blends and nanocomposites. SAXS spectra confirmed the intercalated morphology of nanocomposites. Soil burial test were carried out and the rate of degradation of the samples were measured indirectly. Oxygen gas permeability of EVAc was slightly decreased by adding PLA to the matrix, when small loads of clay caused dramatic improvement in barrier properties. Melt rheological frequency sweep test illustrated the compatibility of EVAc with low contents of PLA. Tensile test cleared that increasing PLA’s content and clay’s load in EVAc results in increase in tensile strength and modulus of the composite.

Impact of mercury speciation on its removal from water by activated carbon and organoclay

Mercury (Hg) speciation can affect its removal efficiency by adsorbents. This study assessed the removal of dissolved inorganic Hg(II) species (Hg(II)*), β-HgS nanoparticles (HgS NP), and Hg complexed with dissolved organic matter (Hg-DOM) by three sorbents: activated carbon (AC), sulfur-impregnated activated carbon (SAC), and organoclay (OC). The effect of ionic composition, solution ionic strength, and natural organic matter (NOM) concentration on the removal of each Hg species was also evaluated. The three adsorbents were all effective in removing Hg(II)*, Hg-DOM, and HgS NPs. Increasing ionic strength decreased the removal of Hg(II)* species due to the formation of ionic Hg species with lower affinity for the sorbents. Added NOM decreased the removal of Hg(II)* and HgS NPs by all sorbents with the OC sorbent being most susceptible to NOM fouling. On a surface area-normalized basis, the OC removed all types of Hg species better than the AC and SAC samples. Moreover, adsorbed Hg-DOM transformed to a β-HgS phase on the OC, but not for AC and SAC. These studies indicate that both Hg speciation and the water quality parameters need to be considered when designing sorbent-based emission controls to meet Hg removal targets.

Nanoengineered Sorbents To Increase the Persistence of the Allelochemical Carvone in the Rhizosphere

This study investigates the changes in sorption/desorption, dissipation, and leaching of the two enantiomeric forms of the allelochemical carvone, R-carvone and S-carvone, after amending an agricultural soil sample with two nanoengineered sorbents: biochar (BC) and organoclay (OCl). The sorption of carvone enantiomers was nonenantioselective and similarly improved by the addition of OCl and BC to the soil. However, OCl-amended soil showed reversible sorption, whereas BC-amended soil displayed sorption-desorption hysteresis. Dissipation of carvone enantiomers was enantioselective. Both amendments increased the half-life of the enantiomers in the soil. This effect was more pronounced for BC-amended soil and for S-carvone. Leaching of R- and S-carvone through soil columns was scarce in unamended soil (<7%), due to their rapid degradation during leaching, and null for OCl- and BC-amended soil, for which much of the applied R- and S-carvone remained in the top 0-5 cm of the amended soil layer. Addition of biochars and organoclays could help increase the persistence of carvone enantiomers in the rhizosphere, which may favor their use as residual pest-management substances.

B10 Nonionic organoclays for environmental uses

B10 Nonionic organoclays for environmental uses

Removal Properties of Anionic Dye Eosin by Cetyltrimethylammonium Organo-Clays: The Effect of Counter-Ions and Regeneration Studies.

The organo-clays (OCs) were prepared by a cation exchange reaction between surfactant (cetyltrimethylammonium, C16TMA) from different counterions (Bromide, Chloride, and Hydroxide). The effect of the counterions was investigated on the physico-chemical properties of the prepared organo-clays. The highest uptake of organic cations (1.60 mmol/g) was achieved using cetyl trimethylammonium bromide solution and the lowest value (0.93 mmol/g) was obtained after modification with cetyl trimethylammonium hydroxide solution starting from the same initial ratio of mmol/g of clay greater than 2.40. The arrangement of C16TMA cations within the interlayer space was assumed to be perpendicular with a tilt angle of 32° to the plane of clay sheets instead of being parallel to the clay surface using C16TMAOH solution at the same ratio. Different techniques were used to characterize these materials. The thermal stability of these organ-clays was investigated using an in-situ X-ray diffraction (XRD) technique. The decomposition of the surfactant moiety occurred at temperatures higher than 215 °C and was accompanied with a shrinkage of the basal spacing value to 1.42 nm. These materials were applied in the removal of an acid dye “eosin.” The removed amount of eosin depended on the initial concentrations and the content of surfactants in the organo-clays. The removal of eosin was found to be an endothermic process. The maximum amount of 90 mg/g was achieved. The preheated treatment temperature of two selected OCs did affect the removal properties of eosin. A progressive reduction was observed at temperatures higher than 200 °C. The regeneration of spent OCs was studied and acceptable removal efficiency was maintained after 4 to 6 cycles depending on the used initial concentrations.

PREPARATION AND CHARACTERIZATION OF POLYPROPYLENE/PLASTICIZED CORN STARCH BLENDS: EFFECT OF ORGANO-MAGHNITE CLAY AND COMPATIBILIZER ON THE MORPHOLOGICAL, MECHANICAL AND THERMAL PROPERTIES

A biobased nanocomposite was prepared from polypropylene (PP) and thermoplastic starch (TPS). Different percentages of polypropylene-grafted-maleic anhydride are added to the two phases to improve their compatibility. This system was reinforced with organoclay, modified by alkylammonium. The compatibilizer effect and TPS on morphology and properties of PP/organoclay nanocomposites obtained by melt compounding are studied. A good dispersion of filler into polymer matrix is demonstrated by X-ray diffraction. Exfoliated structure with improved compatibility between PP and TPS are obtained using MA-g-PP compatibilizer. Scanning electron microscopy proved strong interfacial adhesion between the components. 7% wt of MA-g-PP compatibilizer and 30% wt of TPS without compatibilizer induce an increase in modulus. Tensile strength and elongation decreased in all materials. TGA-DTA showed an increase in decomposition temperature of compatibilized materials.

The Effect of Acetylation on the Hydrolytic Degradation of PLA/Clay Nanocomposites

In this study, the hydrolytic degradation of Poly(lactic acid) (PLA) and acetylated PLA (PLA-Ac)–clay nanocomposites were investigated. The organo clay was obtained by ion exchange reaction using cetyl tri methyl ammonium bromide (CTAB). Nanocomposites containing 2, 5 and 8% mass ratio of organo clay (CTAB-O) were prepared. PLA and its organo clay nanocomposites were characterized by scanning electron microscope (SEM), thermo gravimetric analysis (TGA) and X-ray diffraction (XRD) to determine the morphology before and after hydrolytic degradation. Fourier transform infrared (FTIR) analyses of PLA and PLA-Ac were also obtained. The hydrolytic degradation of polymers and their composites were investigated in the phosphate buffered saline solution (PBS). The results showed that controlled hydrolytic degradation was observed in the samples with end group modification of PLA. While weight loss of PLA films was 28%, that of PLA-Ac films was 18% after 60 days degradation time. The weight loss was obtained as 29.5 and 25.5% for PLA-5 wt% organo clay (PLA/5CTAB-O) and PLA-Ac-5 wt% organo clay (PLA-Ac/5CTAB-O) nanocomposites films, respectively. It was also observed that thermal degradation of PLA-Ac was much more than that of PLA. Hydrolytic degradation increased depending on organo clay content. The end group modificated PLA results in controlled hydrolytic degradation. While hydrolytic degradation in polymer films occurred as surface erosion, bulk erosion was observed in composite films.

The effect of organo-modified silicate nanolayers on the oxygen and water vapor barrier properties of poly(lactic acid)

For improving the oxygen and water vapor barrier properties of poly(lactic acid) (PLA), a new series of PLA-based nanocomposite films containing an organoclay (OC) and a hydrogel were prepared via the solvent casting method. The synthesized hydrogel was used in a PLA system combined with and without the reactive organo-modified clay. Montmorillonite and the protonated form of SABO®STAB UV 94 were used to prepare the OC via an ion-exchange reaction. The modification of silicate layers was investigated by FTIR, XRD, and TGA techniques. The char residue of the OC obtained was 28% lower than that of the neat montmorillonite, which indicated the presence of SABO in the silicate layer structure. In the presence of the OC, the hydrogel showed a synergistic effect to enhance the barrier properties of PLA. The water vapor permeability decreased from 0.243 to 0.224 g/m2·24 hr in PLA/hydrogel-OC nanocomposite containing 3 mass% each of the hydrogel and OC (PSH 6) compared to the neat PLA. Also, the oxygen permeability of PSH 6 was 37% lower than that of the neat PLA.

Influence of modifying agents of organoclay on the properties of nanocomposites based on acrylonitrile butadiene rubber

Solvent blending of organoclay (OC) in polystyrene in combination with melt mixing with acrylonitrile butadiene rubber (NBR) are applied to provide acrylonitrile butadiene rubber/clay nanocomposites. Clay structures based on the prepared 1,12 dibromododecylhydroxyuronium and bromo dodecyl hydroxyuronium as cationic surfactants were prepared. Colloidal suspension of each organoclay in toluene was mixed separately with polystyrene giving two types of polystyrene-organoclay composites. The prepared polystyrene-organoclay PS-OC composites were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The results indicate the formation of polystyrene-organoclay composites with intercalated and partial exfoliated structures. The rheometric study demonstrate an increase in minimum and maximum torques with an increase in cure rate index (i.e. faster scorch and cure times) for the PS-OC (6 phr) incorporated NBR compound compared to unfilled NBR. This effect is more significant with NBR/PS-OC1 composites in comparison to NBR/PS-OC2 composites at the same loading indicating the nanoreinforcement effect of clay on the mechanical properties of these composites. Compounds filled with PS-OC1 exhibit higher tensile strength, Young’s modulus and less elongation at break compared to those compounds filled with PS-OC2. The higher stiffness of PS-OC1/NBR composites reflects the enhancement in hardness of these compounds with respect to those containing PS-OC2. Further increasing of PS-OC loading results in a significant decrease of the properties. This is due to a possible agglomeration formation of PS-OC in rubber matrix. Furthermore, the results of reinforcement of polymers with nanosized particles indicate a promising application of the organoclay and nanocomposites that affords high performance materials.

Enhancing the rheological properties and thermal stability of oil-based drilling fluids by synergetic use of organo-montmorillonite and organo-sepiolite

Abstract This work focused on improving the rheological properties and thermal stability of oil-based drilling fluids by using the mixture of organo-montmorillonite (OMt) and organo-sepiolite (OSep) as the rheological additive. OMt and OSep were prepared in water. X-ray diffraction (XRD), scanning electron microscope and transmission electron microscope were applied to characterize the structure of organoclays (OC). The OC/oil gels were characterized using an appropriate XRD method. Dynamic rheological test was used to appraise the rheological behavior, viscosity, gel strength and thixotropy of OC/oil fluids aged at different temperatures. OMt firstly swelled in oil at low temperature, and then exfoliated above 150 °C. OSep maintained its crystal structure all the time. The mixing of these two OC did not obviously influence their structures. However, the gel formation ability was promoted, resulting in improvement of rheological properties and thermal stability of oil-based drilling fluids. The nanolayers of OMt and nanofibers of OSep interweaved with each other, reinforcing the network structure and protected them form collapse at high temperatures. The mixture of OMt and OSep with mass proportion of 50% for each displayed the optimal rheological properties and thermal ability.

Optimization of mechanical and color properties of polystyrene/nanoclay/nano ZnO based nanocomposite packaging sheet using response surface methodology

Abstract In this study, a new interesting ternary nanocomposite based on polystyrene (PS), nanoclay and zinc oxide nanoparticles (ZnO) has been suggested as a food packaging material. Effects of ZnO (0–2 wt%) and organoclay (Cloisite® 15 A) nanoparticles (0–7.01 wt%), on mechanical and color properties of the general purpose polystyrene (GPPS) sheets were quantitatively investigated using the response surface methodology (RSM). The structural features and surface morphology of resulted nanocomposites and the dispersion quality of nanoparticles in the polymer matrix were studied by scanning electron microscopy (SEM(and X ray diffraction (XRD) analysis. SEM and XRD results showed that the presence of ZnO nanoparticles improved the distribution of organoclay (OC) in the GPPS matrix and vice versa. Regression models were developed for ultimate tensile strength (UTS), strain at break (SB), Young’s modulus (YM), lightness (L) inedx, yellowness index (YI) and whiteness index (WI) as a function of ZnO and organoclay concentrations. Linear and quadratic terms of regression models showed a significant influence on the UTS. In the case of L index, the linear term of organoclay and for SB, linear terms of both nanoparticles effects were significant. The optimized variables were found to be 0.81% ZnO and 0.57% organoclay for a maximum desirability of 0.805.

Effect of organo clay on curing, mechanical and dielectric properties of NR/SBR blends

Natural rubber (NR) and styrene butadiene rubber (SBR) based elastomeric blends reinforced with organically modified Sodium bentonite clay were prepared by two roll mills. Vulcanization parameters such as minimum and maximum torque values scorch and cure times are measured by Oscillating Disc Rheometer. Mechanical properties such as Tensile strength, modulus at 100%, 200% and 300% elongation and elongation at break and Hardness were measured by Universal testing machine and Durometer Shore A hardness meter respectively. Dielectric properties such as dielectric constant (ε’), dissipation factor (tanδ) and volume resistivity (ρv) were measured at room temperature. The curing studies show that torque values are increasing in NR/SBR blends by increase NR content. The scorch and optimum cure time in NR/SBR blends reinforced organo modified clay was found through increase in the SBR content. This may be due to better processing safety of the NR/SBR blends reinforced with organo modified clay. Mechanical properties show that addition of SBR in blends, tensile strength, elongation modulus increases, but 100% modulus slightly increases and no change was observed in Hardness. Dielectric studies show that dielectric constant of NR and SBR rubbers are almost same, it may due to their non-polar nature. But addition of SBR in NR/SBR blend, dielectric constant gradually increases and maximum value observed at 50/50 ratio. But no considerable change was observed in dissipation factor. Frequency dependant resistivity shows that volume resistivity was not changed with respect to frequency up to 3.5 kHz and beyond that the frequency dependence resistivity was found.

Peelable clay/PE nanocomposite seals with ultra-wide peelable heat seal temperature window

Abstract This study shows that the controlled dispersion and distribution of nanoclay in clay/polyethylene (PE) nanocomposites result in peelable sealants with an ultra-wide peelable heat-seal temperature window (ΔTp). Different nanoclays, unmodified montmorillonite (Mt) and organo-modified Mt. (OMt), were examined for their capacity to generate peelable clay/PE nanocomposites in a melt-blending film extrusion process. Clay/PE nanocomposite films containing 6 mass% organoclay (OC) exhibited a cohesive peel behavior with a ΔTp of about 12°C while PE film containing 6 mass% unmodified clay resulted in microcomposite with a lock seal performance. With the same mass% of OC, a much lower peel strength with a significantly broad ΔTp of 45°C was achieved mainly due to the fine dispersion of OMt when PE-grafted-maleic anhydride (PE-g-MA) was used as a compatibilizer. WAXD and TEM results confirmed that a substantial enhancement in the dispersion and distribution of intercalated nanoclays was achieved with PE-g-MA compatibilizer. Finally, an ultra-wide ΔTp of over 100°C was obtained for compatibilized OC/PE nanocomposite sealant containing only 3 wt% OC with partially exfoliated microstructure indicating that the exfoliation of nanoclay is in favor of peelability. The peel fracture mechanics of the clay/PE nanocomposite sealants were examined through T-peel test and SEM imaging. The results showed that the dispersion and distribution of nanoclay along with the interfacial adhesion between nanoclay and matrix are the key factors controlling the peel performance of the sealants.

Adsorption of terpenes from Eucalyptus globulus onto modified beidellite

Abstract The study aims to combine between the valorization of the adsorption ability of the clay mineral and essential oil with insecticidal effect for synthesis of a powder formulation investigated as natural insecticide. The insecticidal formulation created by the adsorption of the terpenes from Eucalyptus globulus essential oil onto the Tunisian clay classed beidellite (Bd). Furthermore, modified beidellite was investigated for increasing the amount of terpenes adsorbed. Organoclays (OC) were prepared by hexadecyltrimethyl ammonium (HDTMA) and didodecyldimethyl ammonium bromide (DDDMA) intercalation in the interlayer space of Bd. The OC was characterized by X-ray diffraction (XRD), Fourier transformed infrared (FTIR) analysis and Textural analysis by nitrogen adsorption desorption (BET method) in order to confirm the success of organic modification. After adsorption studies, the kinetic models are examined. Results show the adsorption of terpenes onto Bd and modified Bd flows the pseudo-second-order model. Moreover, the adsorption ability of terpenes from Eucalyptus globulus oil is enhanced after organic modification, especially HDTMA.

Effects of Impregnation of Organoclay in the Thermo-Physico-Mechanical Properties of Recycled Composite Aluminates as Barrier Material

This paper provides information on the effects of organoclay (OC) impregnation in the thermal, physical and mechanical properties of recycled composite materials. The raw material was a flexible industry trimmings from a food packaging manufacturing plant. Various material testing standards were employed to determine the properties of the recycled materials. Results showed that the recycled material has significant effect in retarding the linear rate of burning due to the yielded ρ – value equal to zero (0). The resistance factors showed that the recycled material is potential as insulation, barrier, or roofing tile. These information is an indication that impregnation of OC enhanced the recycled material to be thermal resistant, gas and water vapor barrier and as potential barrier material.

Mechanical hysteresis, interface and filler–filler structural breakdowns in ethylene vinyl acetate organoclay composites internally lubricated via radiolytically degraded PTFE microparticles

ABSTRACTInclusion of two or more distinct fillers (hybrid fillers) in a matrix is envisaged to entail synergetic advantages. This study reports synthesis and property evaluation of a novel hybrid filler‐based polymer composite containing two types of fillers with distinct attributes namely mechanical reinforcement and internal lubrication. Poly(tetrafluoroethylene) micro‐particles (PTFEMP) were synthesized via radiolytic‐mechanical degradation and used as an internal lubricant for organoclay (OC) reinforced ethylene vinyl acetate (EVA) matrix. Mechanical hysteresis, nonlinear and linear small amplitude oscillatory shear rheology, morphology, small angle X‐ray scattering (SAXS), dynamic coefficient of friction (DCoF), surface wetting and thermoxidative stability of binary and ternary composites were investigated. In EVA/OC composites, PTFEMP acted as an internal lubricant and reduced DCoF in a volume fraction‐dependent fashion. OC and PTFEMP both increased the mechanical hysteresis of EVA; though the magnitude of hysteresis was much less in PTFEMP. Intriguingly, PTFEMP reduced mechanical hysteresis of EVA/OC composites that is work done during loading and unloading stress–strain cycles was considerably reduced with the inclusion of PTFEMP in EVA/OC composites. SAXS results revealed mass fractals and the presence of an interfacial layer in EVA/OC composites but not in EVA/PTFEMP composites. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 509–519

Effect of nanoclay localization on the peel performance of PE based blend nanocomposite sealants

Polyethylene (PE) based clay polymer nanocomposites (CPN) are of great importance to generate peelable seals in packaging industry. This study shows the significant effect of organoclay (OC) localization in PE-based blend sealants on their peel properties, for the first time. Two different immiscible blends composed of PE/ethylene-methyl acrylate copolymer (EMA) and PE/ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA-GMA) were examined for their potential to generate peelable seals upon addition of organo-modified montmorillonite (OMt). WAXD results and TEM observations reveal that OC is localized at the interface of PE/EMA phases while it is localized within the dispersed EMA-GMA phase in the PE/EMA-GMA blend, which is in agreement with the thermodynamic predictions. The incorporation of 4 phr OC converts the lock seal behavior of the PE/EMA blend seal to a peelable behavior over a wide peelable heat seal temperature range (over 35°C). In contrast, the OC/PE/EMA-GMA nanocomposite sealant, in which OC is mostly located within the EMA-GMA phase, shows lock seal performance similar to the PE/EMA-GMA neat blend.

Use of organoclay as a stabilizer for water-in-oil emulsions under high-temperature high-salinity conditions

Emulsified polymer gels are used in near wellbore applications for water shut-off treatment to control produced water in oil and gas reservoirs. The emulsified gels are expected to separate into oil and water phases at reservoir conditions. The stability of emulsified gels, as measured by the separation time, is influenced by the emulsifier type, salinity of the mixing water, and temperature. Although a range of commercial surfactants is used as emulsifiers, their toxicity and high cost are significant drawbacks. Nowadays, various nanomaterials have been developed for quite a few applications in different fields of endeavors, due to their low cost, availability, high surface area, and most prominently environmental-friendly. The proposed alternative organoclay (OC) has been shown to enhance emulsion stability with increasing OC concentration. The total separated volume reduced by a factor of 4.8, due to the decrease in the interfacial tension, when the OC (Cloisite 15A) concentration was increased from 600 to 1000 ppm. The stability of an emulsion prepared using a 6 vol% polyethylene glycol-2 ether (PEG-2E) enhanced by a factor of ∼2 when the concentration of Cloisite 15A was increased from 300 to 1000 ppm. The separation time can be controlled by controlling the OC dose, depending on the application. A chelating agent can be used to reduce the effect of salts on emulsion stability. The OC materials have the potential to be used as cost-effective emulsifiers for PAM/PEI at high temperature (>100 °C) and high salinity (>200,000 ppm). The OC materials can be used as standalone emulsifiers or co-surfactants to enhance the performance of commercial emulsifiers.

Nanocomposite films containing organoclay nanoparticles as an antimicrobial (active) packaging for potential food application

Polyethylene nanocomposite films containing combinations of organoclay (OC) nanoparticles were prepared using extrusion molding method. The physical (X-ray diffraction [XRD] and scanning electron microscopy [SEM]), mechanical (tensile strength [TS] and elongation at break [E]) and antibacterial properties of the films against gram positive and gram negative bacteria were evaluated. XRD results showed an increase in basal reflection and intercalated-exfoliated structure prepared. SEM images revealed that Cloisite 20A had better compatibility with the polyethylene matrix in such way that it distributed homogenously in the matrix. Incorporating nanoparticles into polyethylene matrix significantly improved mechanical properties of the films in terms of TS and E parameters. Among used organoclays, Cloisite 30B, and Cloisite 15A had the most and the least antibacterial effect, respectively. A combination of three studied OCs revealed a more pronounced antibacterial effect than that of single or binary mode. Furthermore, its effect on gram negative Escherichia coli, was more pronounced than gram positive Staphylococcus aureus. Practical applications Nanocomposite films studied in this research provide bacteriostatic activities with improving mechanical properties. The main feature of this study was to use a mixture of nanoparticles for an enhanced antibacterial effect and, therefore, to reduce metallic nanoparticles' concentration in the obtained active films. Thus, such packaging material is suggested for potential use as an optimal choice for antimicrobial food packaging applications.

Synthesis of porous bentonite organoclay granule and its adsorption of tributyltin

We report a new method to synthesise porous organoclay granules which is suitable for high flow rate wastewater treatment applications. Granulation process consists of three steps: mixing natural clay powder, fine coal dust and corn starch into a homogeneous mixture; granulating in a rotating tilted pan granulator by spraying water mist; and heat treatment firstly at 190°C for 30min to solidify and then calcined at 550°C for 4h to create pores. These procedures produced very strong porous clay granules with a crushing strength of 8.41N, the permeability of the granules was 1.56×106mD and hydraulic conductivity of 1.5cm/s. To further enhance the adsorption performance, the granules were later modified by surfactant hexadecyltrimethylammonium bromide (HDTMA) and tested for its adsorption capacity for removing toxic antifouling agent tributyltin (TBT) at high flow rate. It was found that cationic HDTMA modification enhanced the TBT adsorption capacity by 20%. This new granulation method allows the mass production of porous organo clay granules while the porous granular clay is also a good substrate for coating material such as nano sized zero-valent iron to further extent its application.