Thermal Properties of Epoxy Resin/Layered Double Hydroxide Intercalated Nanocomposites / Toplinska svojstva interkaliranih nanokompozita na osnovi epoksidne smole i slojevitog hidroksida

Ca-Al layered double hydroxide (LDH) modifi ed 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 fi nal layered structure. Intercalation of benzoate anions within LDH layers was confi rmed 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 poly(oxypropylene) diamine as a curing agent. Nanocomposites prepared with different contents of LDH-B (5, 10 and 15 phr) were characterised by XRD, FTIR, TGA, differential scanning calorimetry and transmission electron microscopy (TEM). The XRD results indicated formation of intercalated nanocomposites, and TEM analysis confi rmed that LDH-B was dispersed within the matrix forming an intercalated structure, which becomes partially exfoliated in the nanocomposite with 5 phr fi ller. Results of thermal analysis showed detrimental infl uence on initial degradation temperature in comparison to the neat crosslinked epoxy, while residue at 1,000°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. / Pripravljen je Ca-Al slojeviti hidroksid (LDH) modifi ciran benzoatnim anionima (Ca4Al2(OH)12(C6H5COO)2 · x H2O, LDH-B) modifi ciranom metodom rehidratacije, tj. dodavanjem benzojeve kiseline i CaO u smjesu vode i acetona, kojom se trikalcijev aluminat (Ca3Al2O6) pretvara u kona ni slojeviti hidroksid. Interkalacija benzoatnih aniona unutar LDH slojeva potvr ena je rendgenskom difrakcijom (XRD), spektroskopijom u infracrvenom podru ju (FTIR) i termogravimetrijskom analizom (TGA). Interkalirani nanokompoziti na osnovi epoksidne smole i LDHB pripravljeni su in situ polimerizacijom, uz polioksipropilen diamin kao umre ivalo. Uzorci s razli itim udjelom LDH-B (5, 10 i 15 phr) ispitivani su XRD-om, FTIR-om, TGA-om, razlikovnom pretra nom kalorimetrijom i transmisijskom elektronskom mikroskopijom (TEM). Rendgenska difrakcija pokazala je nastajanje interkaliranih nanokompozita, a TEM analiza potvrdila raspr enje LDH-B unutar matrice i nastajanje interkalirane strukture, uz djelomi no raslojavanje u nanokompozitu s 5 phr punila. Toplinska analiza pokazala je smanjenje po etne temperature degradacije u usporedbi s