Intercalation Pathways and Mechanical Properties of Epoxy Clay Hybrid Nanocomposites | NIST (original) (raw)
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Epoxy-montmorillonite clay nanocomposites: Synthesis and characterization
Journal of Applied Polymer Science, 2004
Nanocomposites of epoxy resin with montmorillonite clay were synthesized by swelling of different proportions of the clay in a diglycidyl ether of bisphenol-A followed by in situ polymerization with aromatic diamine as a curing agent. The montmorillonite was modified with octadecylamine and made organophilic. The organoclay was found to be intercalated easily by incorporation of the epoxy precursor and the clay galleries were simultaneously expanded. However, Na-montmorillonite clay could not be intercalated during the mixing or through the curing process. Curing temperature was found to provide a balance between the reaction rate of the epoxy precursor and the diffusion rate of the curing agent into the clay galleries. The cure kinetics were studied by differential scanning calorimetry. The exfoliation behavior of the organoclay system was investigated by X-ray diffraction. Thermogravimetric analysis was used to determine the thermal stability, which was correlated with the ionic exchange between the organic species and the silicate layers. The morphology of the nanocomposites was evaluated by scanning electron microscopy.
Synthesis and characterization of new nanocomposites based on epoxy resins and organophilic clays
Polymer International, 2007
Epoxy-clay nanocomposites were synthesized using different types of modified montmorillonite, either with a classic quaternary ammonium salt or with protonated adducts synthesized by reacting resorcinol diglycidyl ether with monoamines (benzylamine or cyclohexylamine). The chemical structure was investigated using Fourier transform infrared and 1 H NMR spectrometry. The nanocomposite structures were confirmed using X-ray diffraction analysis and transmission electron microscopy. The influence of the montmorillonite modifier on the glass transition temperature of the cured composites was studied using dynamic mechanical analysis.
Characterization of Natural and Modified Clays to the Development of Polymeric Nanocomposites
Macromolecular Symposia, 2011
Bentonite is a technical term applied to layered silicates of very thin granulation, mainly composed by minerals of the smectites group. Montmorillonite, a phylossilicate with layers as thick as 1 nm, is the most common structure in the bentonite clay. The polarity of these materials is incompatible with most of the usual polymers and in order to overcome this problem, chemical modifications are often necessary. The purpose of this work is to evaluate the chemical and physical characteristics of different bentonites by comparing their product data sheets, their performance in the water Foster swelling and their response to chemical modifications of their surfaces structures. The samples were characterized by infrared spectroscopy and X-ray diffraction analysis. All bentonite samples showed effective intercalations of the modifying agent on their surface structures. This behavior showed the possibility of usage of these materials in the polymer layered silicates nanocomposites preparations.
Clay-Epoxy Nanocomposites: Processing and Properties
JOM Journal of the Minerals, Metals and …, 2007
The work described in this paper is focused on evaluating the effect of the processing method and nanoclay (montmorillonite) content on the ten-sile, compressive, and impact proper-ties of clay-epoxy nanocomposites. Nanocomposites are synthesized by two methods: ...
Journal of Applied Polymer Science, 2009
Polystyrene (PS) nanocomposites were prepared by the free-radical polymerization of styrene in the presence of organically modified montmorillonite (MMT) clays. MMT clay was modified with a low-molecularweight and quarternized block copolymer of styrene and 4-vinylpyridine [poly(styrene-b-4-vinylpyridine) (SVP)] with 36.4 wt % PS and 63.6 wt % poly(4-vinylpyridine) (P4VP). Special attention was paid to the modification, which was carried out in different compositions of a solvent mixture of tetrahydrofuran (THF) and water. The swelling behavior of the MMT clay was studied by an Xray diffraction technique. The diffraction peak shifted to lower 2y angles for all of the modified clays, which indicated the intercalation of the quarternized SVP copolymer into the MMT layers in different degrees. Higher interlayer distances, which showed a high degree of block copolymer insertion, were obtained for solvent compositions with THF in water. The resultant nanocomposites were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, thermogravimetric analysis, and dynamic mechanical analysis. The desired exfoliated nanocomposite structure was achieved when the MMT modification was conducted in 50 or 66 wt % THF, whereas the other modifications all resulted in intercalated structures. The resulting exfoliated nanocomposite was found to have better thermal stability and dynamic mechanical performance compared to the others, even with 2% clay loading.
Materials Science and Engineering: A, 2007
In this study, the effect of montmorillonite (MMT) clay modification and concentration on the tensile behavior of MMT/epoxy nanocomposite was investigated. MMT was surface-modified using 3-aminopropyltriethoxysilane. MMT/epoxy nanocomposite samples were fabricated by mixing the unmodified and the surface-modified MMT of 2, 6, and 10 wt%, respectively, with epoxy resin. XRD analysis was performed to determine the increase of spacing between layers, after the modification. Tensile tests were performed on the MMT/epoxy nanocomposite specimens with and without the MMT modification. The results showed that the d-spacing between layers increased by more than 55% with the 3-aminopropyltriethoxysilane modification of MMT. For unmodified MMT/epoxy nanocomposite, as the concentration of clay increased the elastic modulus increased, but the tensile strength was not affected significantly. For surface-modified MMT/epoxy nanocomposite, both the elastic modulus and the tensile strength increased as the concentration of clay increased. Tensile strength and elastic modulus of surface-modified MMT/epoxy nanocomposite were larger than those of unmodified MMT/epoxy nanocomposite, and the modification effect increased with clay concentration. This occurred due to the increased exfoliation of clays along with the improved interfacial strength by the surface modification.
International Journal of Plastics Technology, 2011
Organic-inorganic hybrids involving organo-modified montmorillonite (OMMT) clay and tetraglycidyl diamino diphenyl methane epoxy (TGDDM) were prepared via in situ polymerization by the homogeneous dispersion of various percentages (1-5% w/w) of clay in epoxy matrix resin. The resulting homogeneous epoxy-clay hybrids were modified with 10 wt% of hydroxyl terminated polydiemthyl siloxane (HTPDMS) using γ-aminopropyltriethoxysilane (γ-APS) as coupling agent in the presence of tin catalyst. The siliconized epoxy-clay prepolymers were further modified separately with 15 wt% of bismaleimide (BMI) monomers and cured with diaminodiphenylmethane. The reactions involved during the curing process between epoxy resin, siloxane and BMI were confirmed by using FTIR and DSC curing analysis. The differential scanning calorimetry (DSC) show that the significant increase in glass transition temperatures in the clay filled hybrid epoxy systems than that of neat epoxy resin. The data obtained from thermal studies indicates that the appreciable improvement in hybrid systems was due to the incorporation of MMT clay, BMI and siloxane into epoxy systems. Scanning electron microscopy (SEM) of the hybrid systems show that the homogenous morphology. X-ray diffraction analysis of the clay hybrid systems shows that the amorphous diffraction patterns and the peaks are broadened and nearly disappeared after 24 h swelling, suggesting the formation of exfoliated structure.
Polymer-clay Nanocomposites, Preparations and Current Applications: A Review
Current Nanomaterials, 2016
Polymer-clay nanocomposites (PCN) are the most important nanomaterials of the current decade with wide range of applications. Montmorillonite, vermiculite, sepiolite, laponite, bentonite and attapulgite are the main classes of clay used as reinforcement in polymer nanocomposites. Clay nanocomposites show characteristic features of thermal stability, flame retardancy, barrier and anticorrosive properties. This work comprehensively review current developments and applications of polymer-clay nanocomposites in automotive, sporting goods, coating technology, packaging, insulation, building construction, electrochemical, biomedical and environmental. This work also aims to describe the importance of polymer clay nanocomposites in various fields, especially for environmental applications. Polymer clay based nanocomposites also have the potential to decontaminate and remediate aqueous systems, therefore purification and remediation of contaminated soil and air with the help of clay based nanocomposites have also been discussed.
Recent Advances in Clay/Polymer Nanocomposites
Advanced Materials, 2011
Composite materials represent one of the most active fields in the polymer industry. Many different types of fillers, carbon black, calcium carbonate, glass fibres and talc in the micrometer size range have been added to polymers to provide an improvement of the final product properties. However, this improvement is only achieved at high filler concentrations, which lead to an increase in the viscosity of the material and, hence, problems in processing.