Nanocomposites based on neodymium-doped titanium dioxide (Nd-TiO 2 )/poly(n-butyl methacrylate) (PBMA) have been prepared by an in situ polymerization of butyl methacrylate monomer with varying concentrations of Nd-TiO 2 nanoparticles. The resulting nanocomposites have been analyzed by ultraviolet (UV)-Visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis, and impedance analyzer (TGA). The results of UV and FTIR spectroscopy have indicated the interaction of nanoparticles with the PBMA matrix. Spherically shaped nanoparticles with an average size of 10-25 nm have been revealed in the TEM and their homogeneous dispersion, and interaction of polymer matrix has been confirmed by SEM and XRD studies. The thermal stability and glass transition temperature of the composites were significantly enhanced by the addition of nanoparticles. The AC conductivity and dielectric properties of nanocomposites have been found to be higher than pure PBMA, and the maximum electrical properties have been observed for 7 wt% composite. The reinforcing nature of the nanoparticles in PBMA has been reflected in the improvement in tensile strength measurements. The result indicated that the tensile strength of nanocomposites have greatly enhanced by the addition of Nd-TiO 2 nanoparticles whereas the elongation at break decreases with the loading of nanofillers. To understand the mechanism of reinforcement, tensile strength values have been correlated with various theoretical modeling. The research has been found to be promising in the development of novel materials with enhanced tensile strength, dielectric constant, and thermal properties, which may find potential applications in energy storage and nanoelectronic devices. J. VINYL ADDIT. TECHNOL., 25:9-18, 2019.

Nanocomposites based on poly (n-butyl methacrylate) (PBMA) with various concentrations of titanium dioxide (TiO 2 ) nanoparticles were synthesised by in situ free radical polymerisation method. The formation of nanocomposite was characterised by FTIR, UV, XRD, DSC, TGA, impedance analyser and flame retardancy measurements. FTIR and UV spectrum ascertained the intermolecular interaction between nanoparticles and the polymer chain. The XRD studies indicated that the amorphous region of PBMA decreased with the increase in content of metal oxide nanoparticles. The SEM revealed the uniform dispersion of nanoparticles in the polymer composite. The DSC and TGA studies showed that the glass transition temperature and thermal stability of the nanocomposites were increased with the increase in the concentration of nanoparticles. The conductivity and dielectric properties of nanocomposites were higher than pure PBMA and the maximum electrical property was observed for the sample with 7 wt% TiO 2 . As the concentration of nanoparticles increased above 7 wt%, the electrical property of nanocomposite was decreased owing to the agglomeration of nanoparticles in the polymer. Nanoparticles could impart better flame retardancy to PBMA/TiO 2 composite and the flame resistance of the materials improved with the addition of nanoparticles in the polymer matrix.

Electrically conductive nanocomposite system based on poly(butyl methacrylate) (PBMA) with different contents of neodymium-doped titanium dioxide (Nd-TiO2) was prepared by in situ free radical polymerization method. The effect of Nd-TiO2 on the morphology and structural properties of the composites was carried out by scanning electron microscope (SEM) and X-ray diffraction analysis (XRD). The temperature-dependent AC conductivity and DC electrical conductivity of PBMA/Nd-TiO2 nanocomposites were studied with respect to the different volume fraction of Nd-TiO2 nanoparticles. SEM and XRD patterns revealed the uniform dispersion and structural regularity of nanoparticles in the polymer matrix. The AC conductivity of PBMA and its composites were found to be increased with an increase in temperatures and frequencies. The activation energy and exponential factor were analyzed from AC conductivity and both results indicate the hopping conduction mechanism present in PBMA/Nd-TiO2 nanocomposite, which is responsible for the variation of conductivity with temperature also. The DC conductivity of nanocomposites was higher than pure PBMA and the conductivity increases with increase in the concentration of Nd-TiO2 nanoparticles. Experimental and theoretical investigations based on McCullough, Bueche, Scarisbrick, and Mamunya modeling were carried out to observe the DC conductivity differences induced by the addition of Nd-TiO2 nanoparticles in PBMA matrix. Among the various modeling studied here, Mamunya model shows better agreement with the experimental conductivity.

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Using free radical polymerization process a series of samarium-doped titanium dioxide (Sm 3+ -doped TiO 2 ) nanoparticles containing poly (n-butyl methacrylate) (PBMA) composites were synthesized. The fabricated samples were characterized by XPS, FTIR, UV, XRD, DSC, TGA, flame retardancy studies, and impedance analyser. The shift in FTIR peak of the nanocomposites to higher wavenumber indicates the interfacial interaction between nanoparticles and PBMA. The UV spectra indicated that the metal oxide nanoparticles could enhances the interfacial interaction in the polymer composites. SEM images showed the uniform dispersion of nanoparticles into the macromolecular chain of PBMA. XRD patterns of the composites indicated the ordered arrangement of nanoparticles within the polymer and the regularity of the chain improved by the increase in concentration of nanoparticles. Better flame resistance and thermal stability were attained by the addition of nanoparticles. The flame retardancy and thermal stability of the composites were improved with the increase in concentration of Sm 3+ -doped TiO 2 . The glass transition temperatures of the composites were much enhanced by the increase in weight percentage of nano-filler. The AC conductivity, dielectric constant and dielectric loss tangent of the composites were higher than the pure PBMA and these properties enhanced with the loading of nanoparticles up to 7 wt.% and thereafter the values decreases.