engleski

Thermal properties of epoxy resin/layered double hydroxide intercalated nanocomposites

Ca-Al layered double hydroxide (LDH) modified by the incorporation of benzoate anions (Ca4Al2(OH)12(C6H5COO)2 • x H2O, LDH-B) was prepared by a variation of the rehydration method, by adding benzoic acid and CaO into a mixture of water and acetone used to convert tricalcium aluminate (Ca3Al2O6) into final layered structure. Intercalation of benzoate anions within LDH layers was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Intercalated 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 phr) were characterised by XRD, FTIR, TGA, differential scanning calorimetry and transmission electron microscopy (TEM). XRD results indicated formation of intercalated nanocomposites, and TEM analysis confirmed that LDH-B was dispersed within the matrix forming an intercalated structure, which becomes partially exfoliated in the nanocomposite with 5 phr filler. Results of thermal analysis showed detrimental influence on initial degradation temperature in comparison to the neat crosslinked epoxy, while residue at 1000 °C increases, especially for the partially exfoliated nanocomposite. The glass transition temperature decreases in comparison with the neat crosslinked epoxy, indicating poorer crosslinking of the epoxy matrix.

epoxy resin ; intercalated nanocomposite ; layered double hydroxyde (LDH) ; morphology ; thermal properties

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