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Synthesis and characterization of epoxy resin/layered double hydroxide nanocomposites

Ca-Al hydroxide with layered double hydroxide-ike structure modified by the incorporation of benzoate anions (Ca4Al2(OH)12(C6H5COO)2 · ; x H2O, LDH-B) was prepared by a variant of the rehydration method, by adding benzoic acid and CaO into mixture of water and acetone used to convert tricalcium aluminate (Ca3Al2O6) into final layered structure. Modification of layers with benzoate anions was confirmed by Fourier transform infrared spectroscopy (FTIR). Nanocomposites based on an epoxy resin and LDH-B were prepared by in situ polymerisation, with polyoxypropylene diamine as a curing agent. Nanocomposites prepared with different contents of the LDH-B (5, 10, and 15 %) were characterised by X-ray diffraction analysis (XRD), FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). XRD results indicated that the characteristic layered structure of the LDH-B had disappeared, and TEM analysis confirmed that LDH-B was partially dispersed within the matrix forming an intercalated structure, which becomes partly exfoliated in the sample with 5 % filler. Results of thermal analysis showed somewhat improved thermal properties in comparison to the neat epoxy resin, while the glass transition temperature initially decreases but then increases to values over that of neat epoxy resin for the sample with 15 % filler.

epoxy ; layered nanofiller ; morphology ; nanocomposites ; thermal stability

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