In-Situ Polymerization of Poly (Methyl Methacrylate)/MgAl Layer Double Hydroxides Nanocomposites with High Dispersion an
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0942-W11-30
In-Situ Polymerization of Poly (Methyl Methacrylate)/MgAl Layer Double Hydroxides Nanocomposites with High Dispersion and Enhanced Physics Properties Tsung-Yen Tsai, Shau-Wen Lu, and Fu-Shou Li Dept of Chemistry, Center for Nanotechnology, R&D Center for Membrane Technology, Chung Yuan Christian University, 200, Chung Pei Road, Chung Li City, TAIWAN, 32023, Taiwan
ABSTRACT Poly(methyl methacrylate)/MgAl layer double hydroxides (PMMA/MgAl LDH) nanocomposites were prepared by in situ free radical polymerization with the organic modified MgAl-K2 LDH in the methyl methacrylate monomer and initiator of benzoyl peroxide. The morphologies of MgAl-K2 LDH and PMMA/MgAl-K2 LDH nanocomposites were investigated by transmission electron microscopy (TEM) and powder X-ray diffraction, indicated that the MgAl-K2 LDH were dispersed in PMMA matrix with 1, 3, 5, and 7phr to form PMMA/MgAl-K2 LDH nanocomposites with heterogeneous morphologies comprising both exfoliated and intercalated PMMA/MgAl-K2 LDH nanocomposites. The thermal and mechanical characterization were carried out by thermogravimetric analysis (TGA) 、differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The properties of PMMA/MgAl-K2 LDH nanocomposites exhibit the better thermal and mechanical properties for the application of membranes. Keywords: Nanocomposite, Layer Double Hydroxides (LDH), PMMA, Membrane INTRODUCTION Recently, the most interest in composites has been focused on the development of polymer/clay nanocomposites, prepared by dispersing clay minerals in a polymer matrix and achieved a synergetic combination of mechanical, physical, and thermal properties at extremely low loadings of the inorganic species [1-4]. As far as we are aware; however, these kinds of nanocomposites have been mainly focused on the polymer/layered silicate system. Clays have been studied widely because they are naturally occurring minerals that are commercially available, and exhibit plenty of morphologies with a higher aspect ratio and cation exchange capacities. Noteworthy,
the aspect ratio, layered charge and composition of these natural clays were unable to be changed. The layered double hydroxides (LDHs) have received considerable attention because of their properties as catalysts, anion exchangers, and biological-carrier materials for the immobilization [5–7]. Nevertheless, LDHs have been used to prepare nanoscale organic/inorganic hybrid materials to develop new functional materials such as biological, environmental, agricultural, and pharmaceutical materials and so on [8,9]. The LDHs can be represented by the ideal formula [M2+1-xM3+x(OH)2]x+An-x/n．m H2O, where M2+ and M3+ are divalent and trivalent metal cations, such as Mg2+ and Al3+, respectively. Symbol A, in the ideal formula of LDH, is an anion, such as CO32-, SO42-, and NO3-. Because of their highly tunable properties, LDHs are considered as a new emerging class of the most favorable layered crystals for preparation of multifunctional polymer/layered materials nanocomposites [10].
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