Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) was employed to synthesize well-defined poly (styrene-co-butyl acrylate)/clay nanocomposites. Dodecyltrimethylammonium bromide (DDTMAB) and Vinylbenzyltrimethylammonium chloride (VBTMAC) surfactants were used as clay modifier. The classical surfactant is used to expand the interlayer gallery of montmorillonite; however, double bond of reactive modifier participates in chain propagation process and forms clayattached polymer chains. Subsequently synthesis of attached and free poly (styrene-co-butyl acrylate) chains and their composition was confirmed by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy ( 1 H NMR). Narrow distribution of nanocomposites molecular weight was confirmed by gel permeation chromatography (GPC). Partially exfoliated clay layers in the copolymer matrix were revealed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermal properties of the nanocomposites were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Thermal decomposition of the nanocomposites was hindered in the presence of nanoclay. Dynamic mechanical thermal analysis (DMTA) results show that addition of nanoclay was also resulted in enhanced storage modulus (E′) in comparison with the neat copolymer. Lower glass transition temperature of nanocomposites was displayed by DSC.
In the electronic industry, there is an enormous request for high thermal conductivity polymer. In this regard, we propose a novel synthesis route to produce magnetically alignable 2D-nanofiller. In our work, surface modification of boron nitride nanosheets (BNNs) with polyacrylamide brushes are explored. For this purpose, the postpolymerization reaction of BNNs is followed by the redox polymerization of acrylamide onto the surfaces of already hydroxyl-functionalized BNNs. Afterward, magnetic iron oxide nanoparticles are contributed to modified BNNs through polyacrylamide chelating effect. Finally, to provide high thermal conductive and magnetic responsive nanocomposites, the functionalized Fe 3 O 4 /BNNs are dispersed in epoxy matrix and aligned under an external magnetic field. According to the results of thermal conductivity studies, thermal transport of the nanocomposites increases to 0.37 W/mK by adding only 10% of functionalized Fe 3 O 4 /BNNs (at 25 °C). Mechanical and thermal properties of these nanocomposites are compared with the pristine epoxy polymer as a control sample.
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