Preparation and characterization of exfoliated poly(vinyl acetate-co-methyl methacrylate)/Cloisite 30B nanocomposite

Poly(vinyl acetate-co-methyl methacrylate)/Cloisite 30B, P(VAc-co-MMA)/C30B nanocomposite have been prepared via emulsion polymerization method. In the nanocomposite latex preparation sodium lauryl sulfate, ammonium persulfate, and poly(vinyl alcohol) were as anionic emulsifier, conventional anionic initiator, and stabilizer, respectively. The resulting P(VAc-co-MMA)/C30B nanocomposites with various filler contents were characterized using elemental analysis, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy. The effects of various C30B contents on the polymerization rate and monomer conversion of P(VAc-co-MMA)/C30B were studied. Thermal properties of the nanocomposite were studied by dynamic mechanical thermal analysis. The XRD and TEM results demonstrated that the synthesized polymer chains were aggregated into the C30B interlayer regions and consequently complete exfoliation was produced

Magnetic cobalt-zinc ferrite/PVAc nanocomposite: synthesis and characterization

Metal oxide nanoparticles are the subject of current interest because of their unusual optical, electronic, and magnetic properties. In this work, cobalt zinc ferrite ( Co_(0.3)Zn_(0.7)Fe_2O_4 ) nanoparticles have been synthesized successfully through redox chemical reaction in aqueous solution. The synthesized Co_(0.3)Zn_(0.7)Fe_2O_4 nanoparticles have been used for the preparation of homogenous polyvinyl acetate-based nanocomposite ( Co_(0.3)Zn_(0.7)Fe_2O_4/PVAc ) via in situ emulsion polymerization method. Structural, morphological and magnetic properties of the products were determined and characterized in detail by X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The XRD patterns of the Co_(0.3)Zn_(0.7)Fe_2O_4 confirmed that the formed nanoparticles are single crystalline. According to TEM micrographs, the synthesized Co_(0.3)Zn_(0.7)Fe_2O_4 nanoparticles had nano-needle morphology with an average particle size of 20 nm. The calculated coefficient of variation (CV) of nanoparticles diameters obtained by TEM micrographs was 16.77. The Co_(0.3)Zn_(0.7)Fe_2O_4 nanoparticles were dispersed almost uniformly in the polymer matrix as was proved by SEM technique. The magnetic parameters of the samples, such as saturation magnetization (M_s) and coercivity (H_c) were measured, as well. Magnetization measurements indicated that the saturation magnetization of synthesized Co_(0.3)Zn_(0.7)Fe_2O_4/PVAc nanocomposites was markedly less than that of Co_(0.3)Zn_(0.7)Fe_2O_4 magnetic nanoparticles. However, the nanocompoites exhibited super-paramagnetic behavior at room temperature under an applied magnetic field