Incorporation Of Montmorillonite Research Articles

Nanocomposite of silk fibroin nanofiber and montmorillonite: Fabrication and morphology

The purpose of our research is creating a new nanocomposite material. Generally silk fibroin (SF) is regarded as a promising base material for biomedical uses. The incorporation of montmorillonite (MMT) into SF fibers would improve physical properties of the SF fibers. We investigated a new method of combining electospun SF with MMT. Specifically, electrospun silk nanofibers were treated with methanol and dipped in a MMT suspension. We could obtain a nanosheet composite of silk nanofibers and MMT. Their ultrastructures were successfully visualized by high resolution transmission electron microscopy. This compound was comprised of individual silk nanofibers surrounded by thin layers of MMT, each with a thickness of about 1.2nm. This structure was confirmed by elemental analysis. We also performed IR, NMR and X-ray diffraction analyses in conjunction with morphological data. Conclusively we obtained a new composite of silk nanofiber and MMT, which has never been reported. Using this unique nanocomposite biological tests of its application for a scaffold for tissue engineering are under way.

Thermal stability, crystallization and mechanical properties of nylon11/montmorillonite nanocomposites

AbstractNylon 11 nanocomposites with different montmorillonite loadings were successfully prepared by melt compounding. XRD and TEM show the exfoliated nanocomposites are formed at low montmorillonite concentration (less than 2 wt%) and the intercalated nanocomposites are obtained at higher montmorillonite contents. TGA shows that the thermal stability of the nanocomposites is improved by 27 °C when the montmorillonite content is only 2wt%. At the same time, The crystallization behavior of nylon11/montmorillonite nanocomposites has been studied by means of XRD, DSC.The Avrami equation described well the isothermal crystallization behavior of nylon11 and nylon11/montmorillonite nanocomposites. The results showed that the montmorillonite acted as the nucleating agent and facilitated the crystal growth rate of nylon 11 matrix. The incorporation of montmorillonite did not change the crystal morphology of nylon 11 but increased the crystallization temperature and decreased the crystallization activation energy, which lead to a easy crystallization of nylon11. Mechanical testing shows that the Izod impact strength of all nanocomposites are higher than that of the neat nylon 11, but the tensile strength of the nanocomposites decrease at low nanofiller concentrations (less than 8wt%) and then increased, when the montmorillonite content is 10wt% ,the tensile strength of the nanocomposite is 5% improved than neat nylon 11. This is may be due to the strong interaction between the nylon 11 matrix and the montmorillonite interface.

Incorporation of montmorillonite in epoxy to obtain a protective layer prepared by electrophoretic deposition

An electrophoretic deposition (EPD) process was successfully used to obtain a composite epoxy coating containing montmorillonite. To disperse and obtain the intercalation of montmorillonite particles, a suitable procedure was optimized. This procedure did not require the use of additional chemicals and it was performed at room temperature. The microstructural analysis (TEM and XRD) confirmed that the intercalation of montmorillonite layers with epoxy was achieved. Functional characterisations (EIS and TMA) demonstrated the improved properties of the reinforced epoxy coating with respect to the simple epoxy coating. Moreover, the EPD process resulted more efficient in obtaining a montmorillonite-reinforced epoxy coating than a simple epoxy coating.

Effects of spinning conditions on structure and properties of multifunctional fibers of polyimidoamide nanocomposites

AbstractThe effects of basic fiber‐forming parameters on the porous structure, moisture absorption, and strength properties of fibers from polyimidoamide nanocomposites were examined. Beneficial fiber‐forming conditions were established in consideration of the fiber sorption and strength properties. It was found that the incorporation of montmorillonite into the fiber‐forming polymer resulted in beneficial increases in fiber porosity and internal surface area. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3323–3331, 2006

Evolution of Rubbery Plateau Region above the Melting Point of Poly(ethylene-co-vinylacetate) by the Incorporation of Montmorillonite

Poly(ethylene-co-vinylacetate) (EVA) was mixed with sodium montmorillonite (MMT) at 90/10 wt. ratio. EVA was also mixed with an organophilic montmorillonite (o-MMT) prepared by replacing Na+ in MMT with trimethylstearylammonium cation. The structure and mechanical properties of the composites were studied by scanning electron microscopy (SEM), transmission electron microscopy, wide-angle X-ray diffraction, differential scanning calorimetry, and dynamic mechanical analysis. In the EVA/MMT composite, MMT particles were poorly dispersed in the order of a few µm. The composite was opaque. By contrast, in the EVA/o-MMT composite, the exfoliated silicate layers were nicely dispersed in EVA matrix. It was a transparent material. The composite showed an interesting reinforcing effect; i.e., the rubbery plateau modulus was retained even above the melting point of EVA. The rubbery modulus seems to originate from a formation of the “house-of-cards” structure of silicate layers.