Article

# Synthesis and characterization of polyvinyl acetate/montmorillonite nanocomposite by in situ emulsion polymerization technique

Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran
(Impact Factor: 1.44). 05/2010; 66(9):1255-1265. DOI: 10.1007/s00289-010-0399-2

ABSTRACT

Exfoliated polyvinyl acetate/montmorillonite nanocomposite (PVAc/MMT) was prepared via in situ emulsion polymerization. The
resulting PVAc with various organophilic MMT contents was investigated. In the nanocomposite latex preparation, sodium lauryl
sulfate (SLS), ammonium persulfate (APS), and poly (vinyl alcohol) (PVA) are used as anionic emulsifier, conventional anionic
initiator, and stabilizer, respectively. The samples were characterized using elemental analysis, X-ray diffraction (XRD),
scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM). The XRD and AFM
results demonstrate that the MMT well dispersed at molecular level in the PVAc matrix. Thermal properties of the nanocomposite
were studied by using differential scanning calorimetric analysis (DSC). The exfoliated PVAc/MMT nanocomposite showed a higher
glass transition temperature and a better thermal stability compared to the pure PVAc.

KeywordsNanocomposite–Emulsion polymerization–Polyvinyl acetate–Montmorillonite–Exfoliation–Thermal properties

3 Followers
·
• Source
##### Article: Effects of inorganic nanofillers on the thermal degradation and UV-absorbance properties of polyvinyl acetate
[Hide abstract]
ABSTRACT: The effects of calcium carbonate (CaCO3) and calcium sulfate (CaSO4) nanoparticles on the thermal and UV-absorbing properties of polyvinyl acetate (PVAc) were analyzed in this study. Nanoparticles of CaCO3 and CaSO4 were synthesized by in situ deposition technique. The size and shape of nanoparticles were recognized by X-ray diffraction and scanning electron microscope (SEM) analyses which confirmed that the particle was having a diameter of 25–33 nm. In this technique, the surface modification of nanoparticles was done by non-ionic polymeric surfactant. PVAc/CaCO3 and PVAc/CaSO4 nanocomposites film samples with an average thickness of 30 µm and in the mass ratio of nanoparticles (0–4% (w/w)) were prepared by solution mixing technique. Chemical, structural, and elemental characterizations of nanocomposites were done by, fourier transform infrared, SEM, and energy dispersive X-ray spectroscopy analyses, respectively. Thermal properties of pure polymer and nanocomposites were characterized through differential scanning calorimetric, thermogravimetric, and differential thermogravimetry techniques. The glass transition temperature of nanocomposites increases with increase in content of nanoparticles. It may be due to the interaction between inorganic and organic components. The thermogravimetric analysis results indicate that the thermal degradation temperatures of nanocomposites were enhanced upon the addition of nanosized inorganic fillers. The thermal results show that PVAc/CaSO4 nanocomposites were more thermally stable than PVAc/CaCO3 nanocomposites. The addition of nanoparticles affects degradation mechanism and consequently improves thermal stability of PVAc. The reduction of polymer chain mobility and the tendency of nanoparticles to eliminate free radicals were the principal effects responsible for these enhancements. The ultraviolet–visible (UV–Vis) absorbance spectra of PVAc and its nanocomposites films show that the intensity of absorbance increases with increasing filling content, suggesting that nanocomposites films have greater UV-shielding property.
Journal of Thermal Analysis and Calorimetry 01/2013; 111(1). DOI:10.1007/s10973-011-2153-x · 2.04 Impact Factor
• ##### Article: Magnetic cobalt-zinc ferrite/PVAc nanocomposite: Synthesis and characterization
[Hide abstract]
ABSTRACT: Metal oxide nanoparticles are the subject of current interest because of their unusual optical, electronic, and magnetic properties. In this work, cobalt zinc ferrite ($${\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4}$$) nanoparticles have been synthesized successfully through redox chemical reaction in aqueous solution. The synthesized $${\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4}$$ nanoparticles have been used for the preparation of homogenous polyvinyl acetate-based nanocomposite ($${\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} /{\text{PVAc}}$$) 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 $${\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4}$$ confirmed that the formed nanoparticles are single crystalline. According to TEM micrographs, the synthesized $${\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4}$$ 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 $${\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4}$$ 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 $${\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} /{\text{PVAc}}$$ nanocomposites was markedly less than that of $${\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4}$$ magnetic nanoparticles. However, the nanocompoites exhibited super-paramagnetic behavior at room temperature under an applied magnetic field.
Iranian Polymer Journal 01/2012; 22(1). DOI:10.1007/s13726-012-0098-y · 1.81 Impact Factor
• ##### Article: Preparation and characterization of exfoliated poly(vinyl acetate-co-methyl methacrylate)/Cloisite 30B nanocomposite
[Hide abstract]
ABSTRACT: 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.
Polymer Bulletin 04/2012; 68(6). DOI:10.1007/s00289-011-0665-y · 1.44 Impact Factor