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A facile solvent casting technique has been reported in the fabrication of surface hydroxylated ZnFe2O4 (h‐ZFO) nanoparticles (NPs) filled with poly(vinylidene fluoride) (PVDF) as a matrix. The h‐ZFO filler particles are synthesized from neat ZnFe2O4. The dielectric and electric performance of polymer‐based composites is much related to the interface binding between filler particles and polymer matrix. In this work, the surface alternation technique employed a new path is developed to improve the compatibility between ZFO particles and the PVDF matrix. These PVDF‐ZFO composites were studied by X‐ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The h‐ZFO‐PVDF and ZFO‐PVDF composites are carefully analyzed by dielectric and electric properties by a wide range of frequencies. However, the morphological analysis exhibits uniform dispersion of the h‐ZFO NPs in the PVDF matrix. The h‐ZFO‐PVDF composites have a dielectric constant of about 35 for 1.5 wt.% of filler contents. Moreover, the h‐ZFO‐PVDF composites have lower dielectric loss than PVDF‐ZFO composites. It is suggested that the strong interaction between h‐ZFO filler particles and the PVDF matrix is the main reason for the improvement of dielectric properties. The outcomes of these methods have great potential for making high dielectric constants and relatively suppressed loss PVDF‐ZFO composites for advanced practical applications. [ABSTRACT FROM AUTHOR]

Graphite nanopowder/poly (vinylidene fluoride) (GNP-PVDF) composite films were prepared by using polystyrene 2% divinyl benzene (PDB) via a solution casting technique. The composites had a higher dielectric constant (≈ 76) and relatively lower dielectric loss (<1), than that of the composite GNP-PVDF and pristine PVDF at 1000 Hz. The AC electrical conductivity spectrum well obeyed Jonscher's universal power law. The investigation of the polarisation–electric field loop showed a higher remnant polarisation (3. 15 μC/cm2), when compared with PVDF. It is believed that the PDB-modified GNP-PVDF composites would be a promising material for electronic applications. [ABSTRACT FROM AUTHOR]

Mg doped bismuth ferrite (BiFeO3; BFO) ceramics named as Bi1−xMgxFeO3(BMO), with x = 0, 0.1, 0.15 and 0.2 were synthesized by solid state reaction routes. The structural characterization of the ceramics suggested that there was a slight distortion in the rhombohedral structure of BFO in the doped ceramics. The microstructural analysis revealed that the ceramics were distributed uniformly and homogeneously in Mg doped bismuth ferrite (BMO) as compared to that of pure BFO. The dielectric measurement showed that BMO possessed an enhanced dielectric and electrical properties than that of pure BFO. The ferroelectric measurements signified that BMO possessed comparatively high remanent polarization and lower coercive field than that of pure BFO indicating its (BMO's) enhanced ferroelectric properties. The optical properties illustrated that BMO had comparatively narrower optical energy band gap as compared to that of pure BFO. Hence Mg doped BFO (BMO) having good dielectric, electrical, ferroelectric and narrow band gap could have broader applications in opto-electronic devices than that of pure BFO. [ABSTRACT FROM PUBLISHER]

ABSTRACT In this work, we prepared a series of poly(vinylidene fluoride) (PVDF)-surface functionalized BiFeO3 (h-BFO)-Sodium dodecyl sulfate (SDS) composite films by solvent casting method to investigate the effect of SDS in the composites. The X-ray diffraction confirmed that the structure of h-BFO significantly changed in the PVDF-(h-BFO)-SDS composite in comparison with the rhombohedral structure of pure BiFeO3. The microscopic study illustrated that the composite with a higher percentage of SDS content facilitated the dispersion as well as proper distribution of ceramic particles in the polymer matrix. The presence of different functionalities of respective polymer and the modified fillers was confirmed by FTIR Spectrophotometer. The dielectric and electrical study done by Impedance Analyzer revealed that the SDS treated surface functionalized composites showed relatively higher dielectric properties than that of two phase composites and pure polymer. Finally, the ferroelectric properties of the composite films done by P-E loop tracer revealed that the SDS-treated composites showed an enhanced remanent polarization. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45040. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated the mechanics and morphology of polyphenylene sulfide/liquid crystalline polymer blends compatibilized with a maleic anhydride grafted copolymer. A corotating twin-screw extruder was used to prepare blends of thermotropic liquid crystalline polymer (LCPA-950). It was observed that the compatibilizer played a role in the viscosity of the compatibilized in situ composite.

Silica fillers are often added to elastomer to improve performance in commercial applications. Mixing with different nanofillers in the presence of different curative systems is expected to improve interchain crosslinking between the filler and the elastomer. ZnO is a common curative for many functional elastomers, the authors have tried the possibility of using nanosilica filler and surface modified (Zn ion coated) nanosilica filler in the presence of different curative systems. The surface modified silica offers good results in the development of advanced materials for enhanced mechanical properties and thermal stability. The use of Zn ion coated nanosilica filler led to an increase in the adhesion at interfaces between the modified filler and elastomer matrix. The modified nanosilica filler (Zn ion coated), showed high tensile strength, tensile modulus, hardness, thermal stability and dynamic modulus in the presence of ammonium benzoate curative system as compared to hexamethylenetetramine (HMT) and 4,4′ methylene-bis-(cyclohexalaminecarbamate) (diak IV). The modified silica filler containing composites clearly revealed the predominant interfacial adhesion rather than chemical crosslinking in the presence of ammonium benzoate curative system. [ABSTRACT FROM AUTHOR]

Vamac GR is generally cured by amine curative systems but in some cases peroxide is also used. Here both the curative systems amine (DPG and MDA) as well as peroxide (Varox DCP 40C) have been used. Mixing with different nanofillers in the presence of different curative systems is expected to improve interchain cross-linking between the filler and the elastomer. ZnO is a common curative for many functional elastomers. The possibility of using nanosilica filler and surface modified (Zn-ion coated) nanosilica filler has been tried. The surface modified silica offers good results in the development of advanced materials for enhanced mechanical properties and thermal stability. The use of Zn-ion coated nanosilica filler leads to an increase of the adhesion at the interfaces between the modified filler and the elastomer matrix. The modified nanosilica filler (Zn-ion coated) shows higher mechanical properties, thermal stability, as well as higher dynamic modulus in comparison to the peroxide curative system. The modified silica filler containing composites clearly reveals the predominant interfacial adhesion rather than chemical cross-linking in the presence of an amine curative system. [ABSTRACT FROM AUTHOR]

A Zn-ion coated nanosilica filler has been developed and tested as vulcanizing activator and reinforcing filler for poly(epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether); Hydrin 400. In this study ZnO has been replaced by the Zn-ion coated nanosilica filler with the aim of studying the dual role of this nanofiller. The Zn-ion coated nanosilica filler proved to be a better reinforcing and curing agent than the ZnO added from outside. Poly(epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether) and ethylene thiourea (NA22) was more reinforcing with high state of cure when Zn-ion coated nanosilica filler was used in presence of mercaptobenzoimidazole, in comparison to the peroxide curative system. However, the peroxide cure system offers better thermal stability. ZnO, when added from outside, is less reinforcing than Zn-ion coated nanosilica filler because of improved elastomer–filler surface interaction. [ABSTRACT FROM AUTHOR]

Polyetherimide/Multiwall carbon nanotube (MWNTs) nanocomposites containing as-received and modified (COOH-MWNT) carbon nanotubes were prepared through melt process in extruder and then compression molded. Thermal properties of the composites were characterized by thermo-gravimetric analysis (TGA). Field emission scanning electron microscopy (FESEM) images showed that the MWNTs were well dispersed and formed an intimate contact with the polymer matrix without any agglomeration. However the incorporation of modified carbon nanotubes formed fascinating, highly crosslinked, and compact network structure throughout the polymer matrix. This showed the increased adhesion of PEI with modified MWNTs. Scanning electron microscopy (SEM) also showed high degree of dispersion of modified MWNTs along with broken ends. Dynamic mechanical analysis (DMA) results showed a marginal increase in storage modulus (E') and glass transition temperature (T(g)) with the addition of MWNTs. Increase in tensile strength and impact strength of composites confirmed the use the MWNTs as possible reinforcement agent. Both thermal and electrical conductivity of composites increased, but effect is more pronounced on modification due to formation of network of carbon nanotubes. Addition of acrylic elastomer to developed PEI/MWNTs (modified) nanocomposites resulted in the further increase in thermal and electrical properties due to the formation of additional bond between MWNTs and acrylic elastomers at the interface. All the results presented are well corroborated by SEM and FESEM studies.