Inorganic Montmorillonite Research Articles

Antibacterial Dental Adhesive Containing Cetylpyridinium Chloride Montmorillonite.

Oral bacteria cause tooth caries and periodontal disease. Much research is being conducted to prevent both major oral diseases by rendering dental materials' antimicrobial potential. However, such antimicrobial materials are regarded as 'combination' products and face high hurdles for regulatory approval. We loaded inorganic montmorillonite with the antimicrobial agent cetylpyridinium chloride, referred to below as 'CPC-Mont'. CPC-Mont particles in a 1, 3 and 5 wt% concentration were added to the considered gold-standard self-etch adhesive Clearfil SE Bond 2 ('CSE2'; Kuraray Noritake) to render its antibacterial potential (CSE2 without CPC-Mont served as control). Besides measuring (immediate) bonding effectiveness and (aged) bond durability to dentin, the antibacterial activity against S. mutans and the polymerization-conversion rate was assessed. Immediate and aged bond strength was not affected by 1 and 3 wt% CPC-Mont addition, while 5 wt% CPC-Mont significantly lowered bond strength and bond durability. The higher the concentration of the antimicrobial material added, the stronger the antimicrobial activity. Polymerization conversion was not affected by the CPC-Mont addition in any of the three concentrations. Hence, adding 3 wt% CPC-Mont to the two-step self-etch adhesive rendered additional antimicrobial potential on top of its primary bonding function.

Cotransport of nano-hydroxyapatite and different Cd(II) forms influenced by fulvic acid and montmorillonite colloids

Soil colloids can affect the cotransport of nanoparticles and pollutants. In this study, the influencing mechanisms of organic fulvic acid (FA) and inorganic montmorillonite colloid (MONT) on the cotransport of nHAP and Cd(II) were investigated. Column experiments combined with Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, attachment efficiency calculation and two-site kinetic retention model were applied to study the mechanisms. Results showed that the co-existence of FA or MONT made the transport of nHAP improved by 58–75% and 33–59%, respectively. Both of them could improve the stability of nHAP particles and enhance electrostatic repulsion between nHAP particles and sand. Retention of nHAP in the sand was mainly caused by secondary energy minimum and physical straining. The co-existence of FA or MONT changed the amount of adsorbed species of Cd(II) and decreased the retardation effect of nHAP on Cd(II) transport. With increasing FA concentration, soluble FA·Cd and suspended nHAP·FA·Cd complexes in the system increased. Transport of soluble Cd(II) and total Cd(II) were strengthened due to the concentration effect of FA and the improved stability of nHAP particles. With increasing MONT concentration, the amount of soluble Cd(II) decreased, but that of colloidal Cd(II) (nHAP·Cd and MONT·Cd) increased. Due to the stronger effect of colloidal Cd(II) change than that of the soluble Cd(II) change, the transport of total Cd(II) was improved by 34–57%. The findings of this study can help to understand the fate of nanoparticles and Cd(II) in natural water and soil.

Toward multifunctionality of PEO/PMMA/MMT hybrid polymer nanocomposites: Promising morphological, nanostructural, thermal, broadband dielectric, and optical properties

Different compositional ratio organic polymer blend (PB) matrices of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) and these matrices with inorganic montmorillonite (MMT) nanoclay dispersed PEO/PMMA/MMT hybrid polymer nanocomposites (HPNCs) were prepared through solution-cast followed by melt-press technique. The structures and properties of these PB and HPNCs were comprehensively characterized using several advanced techniques: scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, broadband dielectric spectroscopy (2×101–109 Hz), and ultraviolet–visible (UV–Vis) spectroscopy. The effects of PEO/PMMA blend compositional ratio and the MMT nanofiller concentration on the homogeneity, nano- to micro-sized structures of these PBs and the hybrid composites, variation in intercalated MMT structures, melting temperature of PEO crystallites, and degree of crystallinity were explored. Dielectric dispersion and relaxation processes, electrical conductivity, UV–Vis absorbance with energy band-gap, and other optical parameters of these nanocomposites were influenced by the amounts of constituents and polymer–polymer and polymer–nanofiller interphases in these PB and HPNC materials. The dielectric results showed that these materials were low-permittivity nanodielectrics over a wide radio-frequency range (∼105–109 Hz), but a considerable increase in dielectric permittivity with the decrease in frequency from 105 to 2×101 Hz was predominantly governed by the interfacial polarization which confirmed them as tunable-type dielectrics. The promising multifunctional macro-scale properties and their relationship with the nano-scale structural variables indicated that these state-of-the-art engineered HPNCs were flexible and tunable nanodielectrics and also controllable optical properties smart-materials for advances in polymer-based device technologies.

Adsorption behaviour of clomazone on inorganic and organically modified natural montmorillonite from Bogovina (Serbia)

AbstractThe adsorption behaviour of the herbicide clomazone on inorganic and organically modified montmorillonite from the Bogovina deposit in Serbia was investigated. Montmorillonite was modified first with NaCl and then with organic complexes such as hexadecyltrimethylammonium bromide (HDTMA) and phenyltrimethylammonium chloride (PTMA). Changes in the surface properties and morphology of the montmorillonite before and after the modification with various concentrations of organic complexes were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Adsorption of clomazone on all examined samples was investigated using the batch adsorption method. Montmorillonite modified with HDTMA-bromide displayed greater uptake of the clomazone compared to the PTMA-montmorillonite, and both organically modified montmorillonites displayed greater uptake of the herbicide compared to the inorganic montmorillonite. Comparing the Freundlich coefficient and maximum adsorbed clomazone quantity values obtained by Langmuir model, the levels of adsorption of clomazone decreased in the following order: HDTMA-montmorillonite with 1.00 cation-exchange capacity (CEC) saturation > HDTMA-montmorillonite with 0.75 CEC saturation > PTMA-montmorillonite with 1.00 CEC saturation > PTMA-montmorillonite with 0.75 CEC saturation > HDTMA-montmorillonite with 0.50 CEC saturation > HDTMA-montmorillonite with 0.25 CEC saturation > PTMA-montmorillonite with 0.50 CEC saturation > PTMA-montmorillonite with 0.25 CEC saturation > Na-montmorillonite > raw sample. The type and content of an organic cation plays an important role in the behaviour of clomazone in a solid/liquid system. It is concluded that organically modified montmorillonite from Bogovina might be used as an effective adsorbent for clomazone.

High-barrier polymeric multilayer film with organic and interactive materials

Barrier or encapsulate films are indispensable components of organic electronic devices. The stability of organic electronic devices strongly depends on the efficiency of these barrier films, for they prevent device degradation and moisture penetration in the device. In this study, a hybrid composite multilayer film, comprising an interactive composite layer sandwiched between two composite organic layers, was devised. The middle interactive composite layer (COMM) comprised inorganic montmorillonite dispersed throughout an epoxy and phenoxy polymer (POL) matrix. The external organic composite layers (POL-EZ) consisted of POL and the newly synthesized eugenol benzoxazine (EZ) composite. The new multilayer film exhibited excellent transparency, tensile strength, chemical resistance, and stability. The POL-EZ/COMM/POL-EZ/PET film (where PET denotes polyethylene terephthalate and was used as the substrate) exhibited a remarkable moisture permeation rate of 7.140 × 10−3 gm-2 day-1. Moreover, the multilayer film could be easily processed via roll-to-roll coating processes. Thus, the newly fabricated barrier film is an exceptional candidate for commercialization as barrier films for organic electronic devices.

Tailored montmorillonite nanoparticles and their behaviour in the alkaline cement environment

This is the first time an analytical protocol is proposed to investigate and live-monitor the behaviour of montmorillonite nanoparticles, of different natures, in alkaline cement environment (pH of 12–13). In this study inorganic and organomodified montmorillonite nanoparticles were characterised via TEM, XRD, SEM-EDX and TGA. The inorganic montmorillonite used consisted of a purified montmorillonite commercially available as HPS-clay, and an organomodified montmorillonite, namely XDB-organoclay, consisted of purified montmorillonite modified with Noramonium MB2HT salt. Both montmorillonite nanoparticles were tailored to increase their compatibility with the hydrating cement environment. This gave rise to three different slurries: (i) reference-slurry, (ii) inorganic-slurry, and (iii) organic-slurry. The slurries were characterised and investigated through UV/vis, to measure suspension quality in terms of physical stability and rheological properties, and by AFM and FTIR to determine the chemical stability. The results indicated that the organic-slurry can offer a good stability, preventing aggregation of the clay particles at the targeted pH (13). The inorganic-slurry showed a reduction in surface charge and increased double layer repulsion. At pH13 it was possible to obtain dispersion of the reference slurry although it underwent gelation and became viscous. The research findings informed that the inorganic slurry favours miscibility of the montmorillonite nanoparticles with cement particles and offers additional nucleation sites for CSH. Therefore it can be considered an alternative to organomodified montmorillonite as an addition in cement based materials.

Influence of the organic complex concentration on adsorption of herbicide in organic modified montmorillonite

ABSTRACTThis study was undertaken to determine the impact of the organic complex concentration on the adsorption of herbicide (acetochlor) at the surface of the organic modified montmorillonite. In this work, natural montmorillonite from Bogovina (Boljevac municipality, Serbia) was used for organic modification. Cation-exchange capacity of this montmorillonite was determined using a methylene blue method (86 mmol/100 g of clay). Montmorillonite has been modified first with NaCl and then with hexadecyltrimethylammonium bromide (HDTMA-bromide) organic complex. Saturation of cation exchange capacity (CEC) was 50%, 100%, and 150%. Changes in the properties of the inorganic and organic montmorillonite have been examined using the X-ray diffraction, Fourier transform infrared spectroscopy, and batch equilibrium method. Montmorillonite modified with HDTMA-bromide demonstrated higher uptake of the herbicide, compared to the inorganic montmorillonite. Comparing the values Freundlich coefficients in batch equilibrium method, it can be seen that the adsorption of acetochlor decreased in the series: 0.5 CEC HM > 1 CEC HM > 1.5 CEC HM > NaM.

Physicochemical and Mechanical Properties of Gelatin Reinforced with Nanocellulose and Montmorillonite

Organic rodlike cellulose nanocrystals extracted from sisal fibers and inorganic montmorillonite based on silicate layers were employed to develop bionanocomposites based on gelatin matrix. Bionanocomposites with cellulose na... | Find, read and cite all the research you need on Tech Science Press

Preparation and Characterization of Cellulose/Montmorillonite Hybrid Membranes

The compounding of cellulose and inorganic Montmorillonite (MMT) on microscale molecular level has high potential to greatly improve the thermal stability, decay resistance and other properties of cellulose fibres. Pristine Algerian MMT was first sodium modified as Na-MMT, then organically modified as organophilic OMMT by using Octadecylamine. With OMMT and fibrous cellulose from waste cotton, cellulose/MMT composites were prepared via incorporation from solution process and characterized by XRD, FTIR and TGA. Dimethyl Acetamide/Lithium Chloride (DMAc/LiCl) solvent system was used for dispersing cellulose and clay. Results show that the preparation of OMMT was very successful; the X-ray diffraction results revealed that the interlayer spacing (2.17nm) for OMMT was increased compared with that (1.24nm) for Na-MMT. The composites exhibit higher thermal stability; addition of OMMT can considerably increase the decomposition temperature of cellulose matrix. An increase in thermal stability with clay content was observed by thermal analysis.

Silylation of Al13-intercalated montmorillonite with trimethylchlorosilane and their adsorption for Orange II

The grafting reactions between trimethylchlorosilane (TMCS) and Al13-intercalated montmorillonite were investigated using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and nitrogen adsorption–desorption isotherms. The influence of solvent on the grafting process is discussed. The grafting amount of TMCS was roughly controlled by choosing different solvents. The product prepared in anhydrous ethanol has a high specific surface area and a large pore volume but a low degree of grafting modification; by comparison, the product prepared in cyclohexane has a high loading amount of silane but a low surface area. These organic–inorganic montmorillonites have an excellent adsorption capability for the removal of the anion dye, Orange II. Orange II exists in the interlayer region, not only through the electrostatic interactions between the anionic sulfonic acid groups of Orange II and the interlayer Al polycations, but also through the hydrophobic interactions between Orange II molecules and grafted silane. With particular emphasis on the absorbents prepared in cyclohexane, the removal rate of Orange II remains at 98.7% when the initial concentration is 1000mgl−1. A continuous organic phase is formed in the interlayer space of the products prepared in cyclohexane. The removal of Orange II with this adsorbent is based on both the adsorption on the interface and the partition between the water and the interlayer organic phases.

Synthesis and Characterization of PMMA/MMT Nanocomposites

PMMA/MMT nanocomposites has been prepared by using methyl methacrylate (MMA), montmorillonite (MMT) and ethanolamine as the raw materials via an in-situ free radical polymerization process. The as-prepared nanocomposites were characterized by Fourier transformation infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results show that the poly(methyl methacrylate) and inorganic montmorillonite have been effectively combined. The structure and thermal stability of the as-prepared nanocomposites are different from the content of MMT in the nanacomposites.

Chiral poly(amide-imide)/organoclay nanocomposites derived from pyromellitoyl-bis-l-isoleucine and benzimidazole containing diamine: synthesis, nanostructure, and properties

In this study, a series of polymer–clay nanocomposite materials, consisting of organosoluble poly(amide-imide) (PAI) matrix and dispersed nanolayers of inorganic montmorillonite clay, were successfully prepared by solution dispersion technique. At first, the reactive organoclay was prepared by using protonated l-isoleucine amino acid as a swelling agent for silicate layers of Cloisite Na+. Then, organosoluble PAI containing isoleucine amino acid was synthesized through step-growth polymerization reaction of N,N′-(pyromellitoyl)-bis-isoleucine diacid and 2-(3,5-diaminophenyl)-benzimidazole under green condition using molten tetrabutylammonium bromide. This polymer was end-capped with amine end groups near the completion of the reaction to interact chemically with acidic group of organoclay. Finally, PAI/organoclay nanocomposite films containing 2%, 5%, 10%, and 15% of organoclay were prepared via solution intercalation method through blending of organoclay with the PAI solution. Dispersion of the modified clay in the PAI matrix resulted in a nanostructured material containing intercalated polymer between the silicate layers. Structures of exfoliation were confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. Thermogravimetric analysis data indicated that the addition of organoclay into the PAI matrix increased the thermal decomposition temperatures of the obtained nanocomposites compared to the pure PAI.

Comparative studies on corrosion protection properties of polyimide‐silica and polyimide‐clay composite materials

AbstractComparative studies on corrosion protection properties of polyimide‐silica‐clay composites were studied in this article. A series of polyimide‐silica (PIS), polyimide‐clay (PIC), and polyimide‐silica‐clay composites (PISC) materials, consisting of an organo‐soluble polyimide (ODA‐BSAA) matrix, inorganic silica particles prepared through the sol–gel reaction of tetraethyl orthosilicate (TEOS) and dispersed nanolayers of inorganic montmorillonite clay, were successfully prepared by solution dispersion technique. Then, all samples were characterized by FTIR, powder X‐ray diffraction patterns, transmission electron microscopy, and29Si solid‐state NMR. The main focus of this article is the comparison of the corrosion protection properties of PIS, PIC, and PISC composite materials. Normally, the aspect ratio of clay is higher than silica. Superior dispersion of clay platelets into a polymer matrix may effectively increase the length of diffusion pathways for oxygen and water. The effects of the materials composition on the corrosion protection performance, gas barrier, and optical properties, in the form of both coating and film, were also studied by electrochemical corrosion measurements (e.g., corrosion potential, polarization resistance, corrosion current, and impedance spectroscopy), gas permeability analysis, and UV‐visible transmission spectroscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Synthesis and properties of novel epoxidized soybean oilmodified phenolic resin/montmorillonite nanocomposites

The novel epoxidized soybean oil-modified-phenolic resin/clay nanocomposites(ESO-M-PR/CN) was prepared. The coupling agent-benzyldimethylphenylammonium chloride [C6H5CH2N+(CH3)2C6H5Cl−, B2MP] was adopted to modify the interface between the organic and inorganic phases. The effect of the nanocomposite structure on its physical and chemical properties was discussed. During the synthesizing process of ESO-M-PR/CN, the phenol hydroxyl was etherified by ESO or ESO epoxy resin prepolymer to provide long ESO epoxy segments. Long ESO epoxy resin chain segments enhanced the crosslink density of ESO-MPR/CN. The thermal and mechanical properties exhibit a significant improvement. The temperature at which a weight loss of 5% occurs increases from 287.1 °C to 402.3 °C. The flexural strength increases by 25%, while the flexural modulus increases by 39%. Moreover, the properties of resin were enhanced by the effect of the inorganic nanoparticles, while the size of the nanomontmorillonites in the phenolic resin was characterized with a scanning electron microscope. The particle size of inorganic montmorillonites in the modified system is less than 100 nm.

Homoionic inorganic montmorillonites as fillers for polyamide 6 nanocomposites

The homoionic montmorillonites Ca-MMT, Mg-MMT, Ba-MMT and Ca-MMT intercalated with ε-caprolactam – Ca-MMT·CL were prepared from commercial Na-MMT and characterized by WAXS and TGA. They were used as fillers for nanocomposites of polyamide 6 synthesized either by anionic polymerization of ε-caprolactam (monomer casting) or by melt blending. WAXS analysis showed that the intercalation of MMT by the polyamide was complete for all nanocomposites, with only a very small fraction of exfoliated platelets being detected by TEM. The decrease in the number of layers in the MMT tactoids suggests that tactoid splitting was lower for the blended nanocomposites than for the polymerized ones. Both the rate of polymerization and the polyamide yield in the nanocomposites were comparable to those of an unfilled system. The MMT fillers, the density of which was more than twice that of the ε-caprolactam in which they were suspended, sedimented during the first stage of polymerization. TGA was used to determine the degree of sedimentation at various levels of the resulting mold. In line with the coordination of polyamide chains to the surface cations of MMT particles, the sedimentation level increased in the following sequence: Mg-MMT < Ba-MMT < Ca-MMT·CL << Na-MMT. Ca-MMT was found to be the only non-sedimenting filler suitable for use in the synthesis of polyamide nanocomposites by either monomer casting or the use of reactive injection molding (RIM) technologies.

Preparation and characterization of polyethylene‐g‐maleic anhydride–styrene/montmorillonite nanocomposites

AbstractIt is difficult to prepare polyethylene/montmorillonite by direct melt mixing because of the difference in character between polyethylene and montmorillonite. Therefore, it is necessary to modify polyethylene with polar groups, which can increase the hydrophilicity of polyethylene. At the same time, the inorganic montmorillonite should be modified with long‐chain alkyl ammonium to increase the basing space between the interlayers. Thus, through the grafting of the polar monomer onto the main chain of polyethylene by reactive extrusion, polyethylene/montmorillonite nanocomposites can be prepared by the melt mixing of the grafter and organic montmorillonite. Fourier transform infrared has been used to prove that the monomers are grafted onto polyethylene. X‐ray diffraction and transmission electron microscopy have been employed to characterize the nanocomposites. Furthermore, thermogravimetric analysis measurements show that the thermal stability of the nanocomposites is improved in comparison with that of the virgin materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 805–809, 2006

Synthesis and evaluation of a composite crosslinked copolymer as a particulate fluid diversion agent

AbstractTo meet the needs for polymer particulates for the flooding of oil fields, a composite crosslinked copolymer of hydrophilic monomers [acrylamide (AM) and acrylic acid (AA)] and a hydrophobic monomer [methyl methacrylate (MMA)] was synthesized. In this study, we first added a rare‐earth thermal stabilizer and inorganic montmorillonite (MMT) clay to the copolymer; this showed that the composite crosslinked copolymer exhibited good water‐swelling performance at 200°C, with gel static grade of 5, a toughness index of 1.1170, and a salinity limit of 250,000 mg/L. It also had better injection abilities. The AM/AA/MMA ratio was 4 : 1 : 0.03 w/w, the crosslinker additive content was 0.03 wt %, the thermal stabilizer additive content was 5 wt %, and the clay (MMT) additive content was 13 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4429–4433, 2006

Organo-soluble polyimde (ODA-BSAA)/montmorillonite nanocomposite materials prepared by solution dispersion technique

A series of polymer–clay nanocomposite materials, consisting of organo-soluble polyimide (ODA-BSAA) matrix and dispersed nanolayers of inorganic montmorillonite clay, were successfully prepared by solution dispersion technique and subsequently characterized by FTIR, powder X-ray diffraction patterns, transmission electron microscopy, and atomic force microscopy. Effects of the materials composition on the corrosion protection performance, gas barrier, and optical properties, in the form of both coating and film, were also studied by electrochemical corrosion measurements (e.g., corrosion potential, polarization resistance, corrosion current, impedance spectroscopy), gas permeability analysis, and UV–visible transmission spectroscopy, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1082–1090, 2005

Comparative studies of the properties of poly(methyl methacrylate)–clay nanocomposite materials prepared by in situ emulsion polymerization and solution dispersion

AbstractA series of polymer–clay nanocomposite (PCN) materials consisting of organic poly(methyl methacrylate) (PMMA) and inorganic montmorillonite (MMT) clay platelets were prepared successfully by the effective dispersion of nanolayers of the MMT clay in the PMMA framework through both in situ emulsion polymerization and solution dispersion. The as‐prepared PCN materials obtained with both approaches were subsequently characterized with wide‐angle powder X‐ray diffraction and transmission electron microscopy. For a comparison of the anticorrosion performance, a PCN material (e.g., 3 wt % clay loading) prepared by in situ emulsion polymerization, showing better dispersion of the clay platelets in the polymer matrix, exhibited better corrosion protection in the form of a coating on a cold‐rolled steel coupon than that prepared by solution dispersion, which showed a poor dispersion of the clay nanolayers according to a series of electrochemical corrosion measurements. Comparative studies of the optical clarity, molecular barrier properties, and thermal stability of samples prepared in both ways, as membranes and fine powders, were also performed with ultraviolet–visible transmission spectroscopy, molecular permeability analysis, thermogravimetric analysis, and differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1936–1946, 2004

Preparation and properties of heterocyclically conjugated poly(3‐hexylthiophene)–clay nanocomposite materials

AbstractA series of heterocyclically conjugated polymer–clay nanocomposite (PCN) materials that consisted of organic poly(3‐hexylthiophene) (P3HT) and inorganic montmorillonite (MMT) clay platelets were prepared by in situ oxidative polymerization with FeCl3 as an oxidant. The as‐synthesized PCN materials were characterized by Fourier transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (WAXRD), and transmission electron microscopy (TEM). The effects of the material composition on the anticorrosion, gas barrier, thermal stability, flammability, mechanical strength, and electrical conductivity properties of the P3HT and PCN materials were studied by electrochemical corrosion measurements, gas‐permeability analysis (GPA), thermogrametric analysis (TGA), limiting oxygen index (LOI) measurements, dynamic mechanical analysis (DMA), and a four‐point probe technique, respectively. The molecular weights of extracted and bulk P3HT were determined by gel permeation chromatography (GPC) with THF as an eluant. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3438–3446, 2004