Preparation and characterization of layered double hydroxides - PMMA nanocomposites by solution polymerization

Layered double hydroxides (LDH)-poly( methyl methacrylate) ( PMMA) intercalated-exfoliated nanocomposites were synthesized by solution polymerization of methyl methacrylate (MMA) in the presence of aminobenzoate organically-modified LDH. Preparations of 4-aminobenzoate organically modified LDHs were carried out by applying a chemical coprecipitation reaction. Structural and compositional details of LDH-AB were obtained with Fourier transformed infrared (FT-IR) spectroscopy, Al-27 magic-angle spinning nuclear magnetic resonance (Al-27 MAS NMR), elemental analysis (EA), inductively coupled plasma (ICP) atomic absorption spectrometry and X-ray diffraction (XRD). The morphology of the LDH-AB in the PMMA matrix was identified by employing transmission electron microscopy (TEM), XRD, and UV/ visible transmission spectroscopy. The thermal properties of the nanocomposites were enhanced and their Tg values as well as the decomposition temperatures shifted to a high temperature region as identified by the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). For example, the Tg value and the decomposition temperature of the nanocomposites with 6.4% LDH-AB increased by 19 degrees C and 24 degrees C, respectively.