Untreated MMT Research Articles

Development of Flame-Retarded Nanocomposites from Recycled PET Bottles for the Electronics Industry.

Recycled polyethylene-terephthalate (rPET) nanocomposites of reduced flammability were prepared by combining aluminum-alkylphosphinate (AlPi) flame retardant (FR) and natural montmorillonite (MMT), in order to demonstrate that durable, technical products can be produced from recycled materials. During the development of the material, by varying the FR content, the ratio and the type of MMTs, rheological, morphological, mechanical and flammability properties of the nanocomposites were comprehensively investigated. Related to the differences between the dispersion and nucleation effect of MMT and organo-modified MMT (oMMT) in rPET matrix, analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and Differential Scanning Calorimetry (DSC), mechanical properties of the nanocomposites changed differently. The flexural strength and modulus were increased more significantly by adding untreated MMT than by the oMMT, however the impact strength was decreased by both types of nanofillers. The use of different type of MMTs resulted in contradictory flammability test result; time-to-ignition (TTI) during cone calorimeter tests decreased when oMMT was added to the rPET, however MMT addition resulted in an increase of the TTI also when combined with 4% FR. The limiting oxygen index (LOI) of the oMMT containing composites decreased independently from the FR content, however, the MMT increased it noticeably. V0 classification according to the UL-94 standard was achieved with as low as 4% FR and 1% MMT content. The applicability of the upgraded recycled material was proved by a pilot experiment, where large-scale electronic parts were produced by injection molding and characterized with respect to the commercially available counterparts.

Effect of mechanochemical treatment on structure and electrical properties of montmorillonite

This study investigates the effect of grinding on the structure of montmorillonite (MMT). Both XRD and IR analyses indicate a gradual breakdown of the mineral layers and a decrease of the crystallinity with grinding. The prolonged grinding is accompanied with an amelioration of oxidant capacity of MMT which could be attributed to the conversion of structural Fe2+ to Fe3+ cations caused by adsorbed atmospheric oxygen and/or to the exposition of more Fe3+ cation to the surface of the mineral. The evolution of acidity of MMT during grinding has been carried out by determining the point of zero charge (pHpzc) of MMT and the pH of the aqueous suspension of MMT. It was shown that pHpzc increases with grinding from 6.2 to 8.1 respectively for untreated MMT and that ground for 30 min. On the other side the pH of MMT suspension increases from 4.75 to 8.18 respectively for untreated MMT and that ground for 75 min. These two results indicate that acidity of MMT has been lost during grinding. TGA analysis shows that the thermal decomposition of the ground MMT for 90 min takes place in a single step. This behavior has been explained by the formation of less tightly bound hydroxyl groups. Electrical and dielectric properties have been studied using impedance spectroscopy. It has been established that grinding is accompanied by an increase of dc conductivity and dielectric constant in the range of MHz. Moreover, it has been observed a shift of bound water relaxation frequency to lower frequency. These changes could be attributed to the enhancement of mobility of interlayer cations and to the perturbation of the state of interlayer water which could be connected to the defects in the octahedral sheet rather than being entirely localized at the interlayer space of MMT.

Synthesis of polyurethane/clay nanocomposites based palm oil polyol coating

In this study, we investigated the Polyurethane paint based on palm oil with the addition of nanoparticles montmorillonite as a heat-resistant. The composites with 1 wt%, 3 wt% and 5 wt% of bentonite filler content obtained by synthesizing in situ were investigated and compared to the neat polyurethane matrix material. The processing of bentonite for montmorillonite was done through several stages including: sedimentation, ultrasonication, dried, sieved with a 200 mesh sieve, then characterized. Untreated MMT were isolated and modified with CTAB. The addition of MMT into polyurethane, as much as 5% wt, can increase the heat as evidenced by the TGA test. The TGA results indicated an enhanced thermal stability, as compared to the neat polyurethane. The onset degradation of neat polyurethane and weight reduction began at a temperature of 50150°C and completely decomposed at the temperatures of 380°C and for PU MKS-MMT reduction, the initial weight started at a temperature of 150-200°C in 5 %wt and decomposed in the end at a temperature of 490°C. In this research, we also tested the gloss adhesive polyurethane with the addition of MMT; the result stated that the addition of 5%wt MMT can improve the adhesion of polyurethane. The addition of MMT in polyurethane can also enhance the gloss polyurethane compared with polyurethane coated without the addition of MMT.

Fabrication of Modified MMT/Glass/Vinylester Multiscale Composites and Their Mechanical Properties

Montmorillonite (MMT) may become a preferred filler material for fiber‐reinforced polymer (FRP) composites due to its high aspect ratio, large surface area, and low charge density. In the present paper, MMT/glass/vinylester multiscale composites are prepared with untreated and surface‐treated MMT clay particles with an MMT content of 1.0 wt%. Effects of surface treatment on mechanical properties of MMT/glass/vinylester multiscale composites are investigated through tensile and bending tests, which revealed enhanced mechanical properties in the case of surface‐treated MMT. Thermal properties are studied through thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). X‐Ray diffraction is performed to investigate the interaction between MMT and the matrix. Fourier Transform Infrared (FTIR) is also performed for both untreated and surface‐treated MMT. Furthermore, Field Emission‐Scanning Electron Microscope (FE‐SEM) is conducted to investigate the path of fracture propagation within the composite surface, showing that the surface‐treated MMT based multiscale composite has better interactions with the host matrix than the untreated MMT multiscale composites. These composites with enhanced mechanical strength can be used for various mechanical applications.

Analysis of conditions for the preparation of BSA/MMT composites

AbstractThis study describes a new method for protein fixation that has high, stable, and good repeatable fixation effect without deactivating protein. This method involves intercalating bovine serum albumin (BSA) into montmorillonite (MMT) under different experimental conditions, i.e., the concentration of coupling agent KH570, pH values, ionic strength, and the impact of buffers. The study showed the interaction of buffer systems with pH values had the most significant influence on adsorption quantity. The existence of the buffer increased the adsorption quantity and helped with slow protein releasing, while the phosphate buffer worked better than acetate buffer. More BSA was adsorbed on KH570 treated than untreated MMT, and among the treated samples the most protein released was on MMT treated with KH570 in 100% ethanol and in the acetate buffer solution. Adsorption quantity of the BSA initially increased and then decreased with the increase of the ionic strength. The research on the preparation of MMT/BSA materials provides further information on the study of protein composites.

Emission of volatile organic compounds during processing and use of organoclay-based nanocomposites

Polymer based nanocomposites are a new broad class of materials widely used in a large range of applications as they generally exhibit improved properties compared with the neat polymer. These materials have been known for a few decades and they have been widely studied in academia and industries, regarding their preparation and properties characterization. More recently, environmental, health and public concerns related to air quality have imposed severe worldwide rules regarding the emissions of Volatile Organic Compounds (VOCs), odours and nanoparticles from such materials. Indeed some studies have shown that they may exhibit some risks to human health. In this study, measurements of VOCs, odours and nanoparticles emissions have been carried out on polyether-block-amide copolymer (PEBA) clay nanocomposites. Both the processing and the storage stages have been investigated. These measurements revealed that nanocomposites based on Cloisite™ 30B exhibit stronger odour than sodium montmorillonite (MMT) and that this may constitute a significant drawback for industrial applications despite their outstanding properties. This behaviour has been explained considering the nature of the emitted VOCs (Volatile Organic Compounds). Particularly it has been highlighted that potentially unhealthy compounds can be emitted during the storage of the material. Moreover, another processing route has been tested as an alternative to the use of organo-modified clays. This consists in injecting water during extrusion, with the aim of dispersing untreated MMT in order to get an exfoliated morphology. Measurements have revealed that in addition to substantial savings that can be achieved using this method, it also reduces emissions both during processing and further use, as compared with conventional processes.

Nanostructure and viscoelasticity of layered silicate nanocomposite-electrolyte supports

There is the need for novel polyelectrolytes with enhanced thermal and mechanical properties. In this report, we have reinforced a polyelectrolyte based on pol- y(dimethylaminoethylmethacrylate) (PDMAEM) using nanoclay montmorillonite (MMT), and have studied the thermal and viscoelastic properties. The protonated poly- mer (PDMAEMH) was solution mixed with functionalized MMT. Recognizing that the sort of surfactant may have a profound influence on the physical properties of the poly- mer matrix, neat MMT, and MMT treated with different surfactants (sulfobetaine and ammonia) were used, and the concentration of the nanofiller was varied from 1 to 5%w/ w. Strikingly, while PDMAEM exhibited a glass transition temperature Tg of 32 � C, the protonated PDMAEMH showed Tg ¼ 155 � C. Master curves obtained by applying the time-temperature superposition principle showed that PDMAEM behaved predominantly elastic (G 00 < G 0 ) sug- gesting an entangled polymer melt. However, PDMAEMH exhibited much longer relaxation times, a shift of ca. seven decades in frequency, suggesting that ionic interactions significantly hampered the molecular dynamics. X-ray scat- tering demonstrated that lower concentration and sulfobe- taine surfactant favored exfoliation whereas ammonia and untreated MMT favored intercalation of the nanoplates. Furthermore, an enhancement in dynamic storage shear modulus was observed for the nanocomposites exhibiting intercalated morphologies relative to those displaying an exfoliated morphology. It is then suggested that the molec- ular dynamics is further slowed down due to confinement of the macromolecules between the nanoplates. V C 2011 Wiley

Ultra-Violet Radiationcured Composites Based on Unsaturated Polyester Resin Filled with MMT and Kenaf Bast Fiber

In this study, nanocomposites based on unsaturated polyester cured by ultra-violet (UV) radiation were prepared using Kenaf bast fibre and Montmorillonite (MMT) as reinforcing agent at different percentages. MMT was modified using an ion exchange process by replacing the sodium ions with alkyl ammonium ions from Cetyltrimethylammonium Bromide (CTAB). From the results obtained, the microstructure of MMT modified with CTAB (MMT-CTAB) showed the interlayer spacing of MMT-CTAB was increased and X-ray diffraction analysis indicated that cation exchange between CTAB and MMT was evident. As for the composites prepared from untreated MMT-CTAB, it showed higher mechanical properties as compared to those prepared from untreated MMT. On the other hand, the percentage of Kenaf fiber in the nanocomposites system also plays a crucial role in determining the nanocamposites properties.

Structural Characterization of MMT Modified by Acrylamide

Carbon pillared MMT was prepared from Na-MMT modified by acrylamide. The structural behavior of the MMT and AM/modified MMT were characterized by TG-DTA and DSC. The analysis of modified MMT showed that: the lamellar structure of carbon pillared MMT increases clearly with the carbonization temperature. In the experiment temperature range, the higher the heating temperature, the more significantly carbonization properties of MMT exhibited, and the more apertures of Pillared MMT developed. In the test MMT lamellar spacing of the carbide change with the heating treatment temperature, d001 value of the MMT augmented to the largest when carbonization temperature reach 200°C; the average pore size of treated MMT was larger than untreated MMT, the pore size became the largest average at 400 °C.

Preparation of Unsaturated Polyester Liquid Natural Rubber Reinforced by Montmorillonite

The effect of liquid natural rubber (LNR) on the mechanical properties of unsaturated polyester (UP) has been studied in this article. Mechanical tests, such as impact and tensile test, have been conducted on the UP-LNR sample in order to determine the optimum LNR composition. The results showed that the tensile strength and impact energy increased with LNR and optimized at 10 phr. The optimum composition of LNR was used to prepare the composite with montmorillonite (MMT). X-ray diffraction of the composite showed the absence of peak in nanocomposites, which contain treated MMT. Scanning of electron microscopy also clearly showed that the agglomeration of clay occurs in the composite using untreated MMT, but is significantly reduced in size for the composite using treated MMT. On the other hand, the mechanical properties, such as tensile strength, tensile modulus, and impact energy, of the composites with modified MMT were also higher than the composite with unmodified MMT. The optimum composition of modified MMT in the composite was found at 4% filler loading.

Preparation and characterization of nanocomposite material based on polyurethane acrylate macromonomer

AbstractIn the present investigation, a macromonomer of polyurethane acrylate (PUA) was synthesized, and novel netlike nanocomposite materials were prepared through in situ polymerization of polyurethane acrylate macromonomers in the presence of organically modified montmorillonite (oMMT). The structure of oMMT was compared with untreated MMT by Fourier transform infrared (FTIR) and X‐ray diffraction (XRD). Transmission electronic microscopy (TEM) studies showed that the silicate layers of oMMT were dispersed homogeneously in the polymer matrix. Tensile test, impact test, and thermal gravity analysis proved that the mechanical and thermal properties of the nanocomposites are superior to those of the pure system, and the mechanical properties of the cured hybrid reach maximum while the content of oMMT is 1.5 wt%. Surprisingly, dynamic mechanical thermal analysis (DMTA) displayed that the glass transition temperature (Tg) of the nanocomposites decreased with increasing the oMMT contents. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Synthesis and interfacial properties of montmorillonite/polypyrrole nanocomposites

Montmorillonite/polypyrrole (MMT/PPy) nanocomposites were prepared by the in situ polymerization of pyrrole in the presence of MMT. The morphology of the MMT/PPy nanocomposites as examined by scanning electron microscopy differs slightly from that of the untreated MMT but markedly from that of polypyrrole. X-ray photoelectron spectroscopy (XPS) showed that the materials have MMT-rich surfaces, an indication that polypyrrole is essentially intercalated in the host clay galleries. The transmission electron microscopy showed, that the interlamellar spacing of the untreated MMT increased from 1.25 to 18.9 nm, when compared to nanocomposite MMT/10.8% PPy. Moreover, XPS highlighted the cation exchange of Na + from montmorillonite by K + (from the oxidant) and by the positively charged polypyrrole chains. Inverse gas chromatography indicated that the nanocomposites are high surface energy materials with a dispersive contribution to the surface energy ( γ S d ) reaching 200 mJ/m 2 at 150 °C, for a PPy loading of 21.4 wt%. The ( γ S d ) values of the MMT/PPy nanocomposites were correlated to the changes in the specific surface area of the MMT induced by the intercalation of polypyrrole.

Montmorillonite/polypyrrole nanocomposites. The effect of organic modification of clay on the chemical and electrical properties

Montmorillonite/polypyrrole (MMT/PPy) nanocomposites, with 15% mass loading of PPy, were prepared by the in situ polymerization of pyrrole in the presence of montmorillonite (MMT) or organo-modified montmorillonite (oMMT) in aqueous solutions containing an oxidant and an anionic surfactant. The morphology of MMT/PPy nanocomposites distinctly differs from that of the untreated MMT as shown by SEM. X-ray photoelectron spectroscopy showed that the MMT/PPy nanocomposite has an MMT-rich surface, whereas the oMMT/PPy nanocomposite surface has a rather organic nature. Due to the organic modification of MMT by the alkylammonium chloride, polymerization of pyrrole at the surface of oMMT is much more efficient in producing a conductive adlayer resulting in an enhancement of conductivity of the oMMT/PPy nanocomposites (1.1 S cm − 1 ) compared to MMT/PPy (3.1 × 10 − 2 S cm − 1 ). The difference in the behaviour of oMMT/PPy and MMT/PPy is interpreted in terms of surface energy minimization by the alkylammonium ions present at the surface of organo-modified MMT. Indeed, the dispersive contribution to the surface energy ( γ s d), as determined by inverse gas chromatography at 150 °C, was estimated to be 34.0 mJ/m 2 for oMMT, much lower than the value of 216 mJ/m 2 determined for MMT.