Preparation,characterization, and dynamic adsorption–desorption studies on polypyrrole encapsulated TiO2 nanoparticles

Binary doped polypyrrole (PPy) encapsulated Titania (TiO₂) nanoparticles were prepared by oxidative polymerization using FeCl₃ as oxidant in presence of camphorsulfonic acid (CSA) as surfactant. Both FeCl₃ (oxidant) and camphorsulfonic acid (surfactant) also act as dopant and hence thus prepared polypyrrole/Titania (TiO₂@PPy) is termed as binary doped nanocomposite i.e. FeCl₃ dopes polypyrrole by oxidation mechanism while camphorsulfonic acid dopes polypyrrole by protonic doping mechanism. The TiO₂@PPy coreshell nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetry, differential scanning calorimetry (DSC), field emission‐scanning electron microscopy (FE‐SEM), and inductance‐capacitance‐resistance (LCR) measurements. The results indicated that the structural and electrical properties of the TiO₂@PPy coreshell nanocomposites were significantly influenced by the extent of TiO₂ nanoparticles loading of polypyrrole. The direct current (DC) electrical conductivity of the as‐prepared TiO₂@PPy coreshell nanocomposites was higher than that of PPy. As‐prepared TiO₂@PPy coreshell nanocomposites were also studied for their dielectric losses for alternating current (AC) which is useful characteristic for their application in the fabrication of charge storing devices. TiO₂@PPy coreshell nanocomposites showed synergistic effect of combining components in improving their alcohol sensing properties. This improvement may be attributed to the adsorption on and desorption from alcohols TiO₂@PPy interface of the nanocomposites and alcohol vapors causing decrease in depletion region. The TiO₂@PPy coreshell nanocomposites were observed to show better reproducibility of electrical conductivity and fast self‐recovery during the alcohol vapor sensing process. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43411.     

Thermal stability of HCl‐doped‐polyaniline and TiO2 nanoparticles‐based nanocomposites

Electrically conductive HCl doped polyaniline (Pani) : titanium dioxide (TiO₂) nanocomposites thin films were prepared by in‐situ oxidative polymerization of aniline in the presence of different amounts of TiO₂ nanoparticles. Later film casting was done using N‐Methyl‐2‐pyrrolidone (NMP) as a solvent. The formation of Pani : TiO₂ nanocomposites were characterized by Fourier Transform Infra‐Red spectroscopy (FTIR), x‐ray diffraction (XRD) and thermogravimetric analysis (TGA). The stability of the nanocomposites in terms of direct‐current electrical conductivity retention was studied in air by isothermal and cyclic techniques. The films of Pani : TiO₂ nanocomposites were observed thermally more stable under ambient environmental conditions than pure polyaniline film. The stability was seen to be highly dependent on the content of TiO₂ nanoparticles in the nanocomposite films. Due to their high stability, such type of nanocomposites can find place as a replacement material for pure polyaniline in electrical and electronic devices. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of polypyrrole using TiO2 nanotube@poly(sodium styrene sulfonate) as dopant and template

A polypyrrole (PPy) using TiO₂ nanotube@poly(sodium styrene sulfonate) (TiO₂@PSS) as dopant and template was synthesized by chemical oxidation polymerization. The template TiO₂@PSS consisting of a TiO₂ nanotube core and PSS on the surface was prepared by a “grafting from” approach. PPy on the layer of TiO₂@PSS (TiO₂@PSS/PPy) was characterized by transmission electron microscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy (XPS), Fourier‐transform infrared spectrometry (FTIR), Raman spectroscopic analysis, UV‐visible (UV‐vis) spectroscopy, thermo gravimetric analysis, and electrical conductivity analysis. Results showed that TiO₂@PSS/PPy was successfully fabricated. The electrical conductivity of the TiO₂@PSS/PPy nanocomposites at room temperature was 11.6 S cm⁻¹, which was higher than that of the PPy (4.2 S cm⁻¹). This result was consistent with those based on FTIR, UV‐vis spectroscopy, and XPS analyses. The nanocomposites have nanoparticle size and controllable morphology and thus potential applications in photoelectrochemical devices, photocatalytic devices, conductive inks, electronic printing sensors, and electrodes. POLYM. COMPOS., 37:462–467, 2016. © 2014 Society of Plastics Engineers     

Effects of carbon‐coated titanium dioxide nanoparticles as a photostabilizer on the photodegradation of rigid poly(vinyl chloride)

In this study, nanocomposites of rigid poly(vinyl chloride) (UPVC) using the synthesized carbon‐coated titanium dioxide (TiO₂) nanoparticles and commercial powder of titanium dioxide (with rutile structure) were prepared by melt blending. The presence of carbon‐coated TiO₂ nanoparticles with rutile structure in UPVC matrix led to an improvement in photo stability of UPVC nanocomposites in comparison with commercial UPVC. The photocatalytic degradation behavior of nanocomposites was investigated by measuring their structural changes, surface tension, and mechanical and morphological properties before and after UV exposure for 700 h. It was found that mechanical and physical properties of UPVC nanocomposites are not considerably reduced after UV exposure in the presence of carbon‐coated TiO₂ nanoparticles even in small percentage of nanoparticles in comparison with the presence of commercial TiO₂ particles. Therefore, it can be concluded that UPVC/TiO₂ nanocomposite with low content of carbon‐coated TiO₂ nanoparticles(0.25 wt %) illustrated high stability under light exposure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40228.     

Preparation and characterization of conductive and magnetic PPy/Fe3O4/Ag nanocomposites

In this article, conductive and magnetic nanocomposites composed of polypyrrole (PPy), magnetite (Fe₃O₄) nanoparticles (NPs), silver (Ag) NPs, have been successfully synthesized with a two step process. First, the PPy/Fe₃O₄ was prepared by the ultrasonic in situ polymerization. Next, the PPy/Fe₃O₄/Ag was synthesized through the electrostatic adsorption. The products were characterized by fourier‐transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), Thermogravimetric (TG), conductivity and magnetization analysis, and the results showed that the Ag NPs with the good conductivity coated uniformly on the surface of PPy/Fe₃O₄ and improved the conductivity of PPy/Fe₃O₄/Ag composites. In addition, as compared with PPy/Fe₃O₄, PPy/Fe₃O₄/Ag composites also have the excellent electro‐magnetic property and enhanced thermostability. POLYM. COMPOS., 35:450–455, 2014. © 2013 Society of Plastics Engineers     

A novel route for the synthesis of poly(2‐hydroxyethyl methacrylate) grafted TiO2 nanoparticles via surface thiol‐lactam initiated radical polymerization

Hybrid nanocomposites of poly(2‐hydroxyethyl methacrylate) (PHEMA) and TiO₂ nanoparticles were synthesized via surface thiol‐lactam initiated radical polymerization by following the grafting from strategy. Initially, TiO₂ nanoparticles were modified by 3‐mercaptopropyl trimethoxysilane to prepare thiol functionalized TiO₂ nanoparticles (TiO₂? SH). Subsequently, surface initiated polymerization of 2‐hydroxyethyl methacrylate was conducted by using TiO₂? SH and butyrolactam as an initiating system. The anchoring of PHEMA onto the surface of TiO₂ nanoparticles was investigated by FTIR, ¹H‐NMR, XPS, TGA, and XRD analyses. The experimental results indicated a strong interaction between PHEMA and TiO₂ nanoparticles owing to covalent bonding. The TEM and SEM images of PHEMA‐g‐TiO₂ showed that the agglomeration propensity of TiO₂ nanoparticles was significantly reduced upon the PHEMA functionalization. The molecular weight and polydispersity index of the cleaved PHEMA from the surface of TiO₂ nanocomposites were estimated by GPC analysis. An improved thermal property of the nanocomposites was observed from TGA analysis. PHEMA‐g‐TiO₂ nanocomposites were found to be highly dispersible in organic solvents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and characterization of polypyrrole/TiO2 nanocomposites by reverse microemulsion polymerization and its photocatalytic activity for the degradation of methyl orange under natural light

PPy/TiO₂ nanocomposites were successfully prepared by reverse microemulsion polymerization and used as an effective photocatalyst for the degradation of methyl orange. Titanium dioxide (TiO₂) was modified by silane coupling agent to improve the dispersity before the polymerization. X‐ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier‐transform infrared spectra were carried out to characterize the morphology and structure of the samples. TEM analysis shows that TiO₂ particles are deposited by polypyrrole (PPy) and the existence of PPy mitigates the agglomeration of TiO₂. XRD spectra reveal that the deposition of PPy does not change the structure of TiO₂ particles. Uv–vis analysis shows that the PPy/TiO₂ nanocomposites have a higher photocatalytic activity under natural light than neat TiO₂. The highest degradation rate occurs when the mass ratio of PPy to TiO₂ is kept at 0.02. POLYM. COMPOS., 34:1076–1080, 2013. © 2013 Society of Plastics Engineers     

Effect of electrical properties on gas sensitivity of polypyrrole/cds nanocomposites

In the present work, polypyrrole (PPy) nanocomposites were synthesized using ferric chloride (FeCl₃) as an oxidant by in situ polymerization at room temperature. Cadmium sulfide (CdS) nanoparticles were synthesized by ultrasonication technique with size ranging between 60 and 110 nm. The PPy/CdS nanocomposites were prepared by taking 1–3 wt % loading of CdS to measure the electrical conductivity. The PPy nanocomposites were characterized by using FTIR, X‐ray diffraction, UV, and SEM. Furthermore, these PPy/CdS nanocomposites were investigated to study their effect of electrical properties on gas sensitivity of ammonia and LPG. The nanocomposites showed improvement in conductivity and sensing response toward 250 ppm NH₃ was found to be maximum (4.2) compared with 100 and 500 ppm NH₃ gas, whereas in the case of LPG, it showed sensitive response. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42379.     

Fabrication of core–shell nanocomposites with enhanced photocatalytic efficacy

The current study establishes the unprecedented involvement in the evolution and production of novel core–shell nanocomposites composed of nanosized titanium dioxide and aniline‐o‐phenylenediamine copolymer. TiO₂@copoly(aniline and o‐phenylenediamine) (TiO₂@PANI‐o‐PDA) core–shell nanocomposites were chemically synthesized in a molar ratio of 5:1 of the particular monomers and several weights of nano‐TiO₂ via oxidative copolymerization. The construction of the TiO₂@PANI‐o‐PDA core–shell nanocomposites was ascertained from Fourier transform IR spectroscopy, UV–visible spectroscopy and XRD. A reasonable thermal behavior for the original copolymer and the TiO₂@PANI‐o‐PDA core–shell nanocomposites was investigated. The bare PANI‐o‐PDA copolymer was thermally less stable than the TiO₂@PANI‐o‐PDA nanocomposites. The core–shell feature of the nanocomposites was found to have core and shell sizes of 17 nm and 19–26 nm, respectively. In addition, it was found that the addition of a high ratio of TiO₂ nanoparticles increases the electrical conductivity and consequently lowers the electrical resistivity of the TiO₂@PANI‐o‐PDA core–shell nanocomposites. The hybrid photocatalysts exhibit a dramatic photocatalytic efficacy of methylene blue degradation under solar light irradiation. A plausible interpretation of the photocatalytic degradation results of methylene blue is also demonstrated. Our setup introduces a facile, inexpensive, unique and efficient technique for developing new core–shell nanomaterials with various required functionalities and colloidal stabilities. © 2018 Society of Chemical Industry     

TiO2‐Oligoaldaramide nanocomposites as efficient core‐shell systems for wood preservation

Homogeneous core‐shell systems were obtained with a growth, in controlled steps, of several oligoamides on TiO₂ nanoparticles. Derivatives of natural compounds, such as l ‐tartaric acid and α,α′‐trehalose, were used as diesters in the polycondensation reactions with ethylenediamine. TiO₂ anatase was chosen because of its high photo‐activity and its antimicrobial activity. The TiO₂ nanoparticles had been previously activated then functionalized using two different coupling agents, and finally, the TiO₂‐oligoamide nanocomposites were synthesized using two synthetic pathways. The final products were characterized by ¹H NMR, ¹³C NMR, FT‐IR, and transmission electron microscope. These nanocomposites can show improved properties in comparison with the single components (TiO₂ nanoparticles or oligoamides), which are useful in many fields, such as antimicrobial coatings for surfaces in cultural heritage conservation. A nanocomposite (TiO₂‐polyethylenetartaramide) was used for applicative studies, and it has shown a good efficacy against fungal attack by Trametes versicolor on wood specimens (Fagus sylvatica). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42047.     

Synthesis of polypyrrole‐modified TiO2 composite adsorbent and its adsorption performance on acid Red G

The adsorption–desorption characteristics of Acid Red G (ARG) on the polypyrrole‐modified TiO₂ (PPy/TiO₂) composite as a novel adsorbent was investigated. PPy/TiO₂ was synthesized via the in‐situ polymerization of pyrrole monomer in the prepared TiO₂ sol solution. Results from X‐ray diffraction and Fourier transform infrared spectra indicated the formation of the PPy/TiO₂ composite. The adsorption experiments showed that the modification of PPy substantially improved the adsorption and regeneration abilities of PPy/TiO₂. The adsorption equilibrium was achieved in a short time of 20 min, and the adsorption kinetics followed the pseudo‐second‐order model. The Langmuir adsorption isotherm was found for PPy/TiO₂, with the maximum adsorption capacity of 179.21 mg/g. The regeneration experiments showed that PPy/TiO₂ could be successfully regenerated by simple alkali‐acid treatment. The adsorption efficiency of the regenerated PPy/TiO₂ adsorbent for ARG was still greater than 90% after regeneration for 10 times. Additionally, the adsorption efficiency of PPy/TiO₂ for the ARG effluent was still higher than 78% after adsorption–desorption for four times. It is expected that the PPy/TiO₂ composite can be considered as a stable adsorbent for the removal of dye. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mechanical properties and nonisothermal crystallization kinetics of polyamide 6/functionalized TiO2 nanocomposites

Titanium dioxide (TiO₂) nanoparticles were pretreated with excessive toluene‐2,4‐diisocyanate (TDI) to synthesize TDI‐functionalized TiO₂ (TiO₂‐NCO), and then polymeric nanocomposites consisting of polyamide 6 (PA6) and functionalized‐TiO₂ nanoparticles were prepared via a melt compounding method. The interfacial interaction between TiO₂ nanoparticles and polymeric matrix has been greatly improved due to the isocyanate ( NCO) groups at the surface of the functionalized‐TiO₂ nanoparticles reacted with amino groups ( NH₂) or carboxyl ( COOH) groups of PA6 during the melt compounding and resulted in higher tensile and impact strength than that of pure PA6. The nonisothermal crystallization kinetics of PA6/functionalized TiO₂ nanocomposites was investigated by differential scanning calorimetry (DSC). The nonisothermal crystallization DSC data were analyzed by the modified‐Avrami (Jeziorny) methods. The results showed that the functionalized‐TiO₂ nanoparticles in the PA6 matrix acted as effective nucleation agents. The crystallization rate of the nanocomposites obtained was faster than that of the pure PA6. Thus, the presence of functionalized‐TiO₂ nanoparticles influenced the mechanism of nucleation and accelerated the growth of PA6 crystallites. POLYM. COMPOS., 35:294–300, 2014. © 2013 Society of Plastics Engineers     

Retracted: Effect of surface‐treated TiO2 on non‐isothermal crystallization behavior of poly trimethylene terephthalate nanocomposites

The study of the non‐isothermal crystallization behavior of poly(trimethylene terephthalate) (PTT)/TiO₂ nanocomposites using untreated and surface‐treated TiO₂ has been carried out with different theoretical models. The PTT/untreated TiO₂ and surface‐treated TiO₂ nanocomposites were prepared employing batch mixing technique with an aim to investigate the influence of the TiO₂ dispersion on the crystallization behavior. The nucleation efficiency of the TiO₂ nanoparticles has been demonstrated with the use of Avrami and Jeziorny models. Test results indicated that the PTT matrix with surface‐treated TiO₂ particles has higher crystallization temperature and melting point than those with untreated PTT/TiO₂ nanocomposites. Unlike untreated TiO₂, surface‐treated TiO₂ particles also showed less effect on the degree of crystallization of the PTT matrix. The TiO₂ nanoparticles act as a nucleating agent in the PTT matrix by reducing the t_½ of the crystallization time, thus making it easy to form crystals. © 2012 Society of Plastics Engineers     

Ferromagnetic polyaniline/TiO2 nanocomposites

Novel ferromagnetic semiconducting polyaniline PANI/TiO₂ nanocomposites were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous medium, in the presence of colloidal TiO₂ nanoparticles (d ∼ 4.5 nm), without added acid. The morphological, magnetic, structural, and optical properties of the PANI/TiO₂ nanocomposites prepared at initial aniline/TiO₂ mole ratios 80, 40, and 20 were studied by scanning electron microscopy, superconducting quantum interference device, X‐ray powder diffraction, FTIR, Raman, and UV‐Vis spectroscopies. The emeraldine salt form of linear PANI chains as well as the presence of phenazine units, branched PANI chains, and anatase crystalline structure of TiO₂ in PANI/TiO₂ nanocomposites was confirmed by FTIR and Raman spectroscopies. The electrical conductivity of synthesized composites was ∼10⁻³ S cm⁻¹. The room temperature ferromagnetic response with coercive field of H_c ∼ 300 Oe and the remanent magnetization of M_r ∼ 4.35 × 10⁻⁴ emu/g was detected in all investigated PANI/TiO₂ nanocomposites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Effect of neodymium‐doped titanium dioxide nanoparticles on the structural,mechanical, and electrical properties of poly(butyl methacrylate) nanocomposites

Nanocomposites based on neodymium‐doped titanium dioxide (Nd‐TiO₂)/poly(n‐butyl methacrylate) (PBMA) have been prepared by an in situ polymerization of butyl methacrylate monomer with varying concentrations of Nd‐TiO₂ 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‐TiO₂ 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. © 2018 Society of Plastics Engineers     

Novel Ni/polypyrrole and Cu/polypyrrole composites prepared in the presence of different acids: Synthesis and investigation of thermal stability

We report the synthesis and characterization of new organic/inorganic hybrid materials constituted of Ni(0) and Cu(0) nanoparticles and polypyrrole (PPy). Copper and nickel nanoclusters were synthesized by a chemical reduction of aqueous metal salt solutions by sodium borohydride. PPy/Ni(0) and PPy/Cu(0) composites were obtained in the presence of two different acids (H₃BO₃, CH₃COOH), by polymerizing pyrrole‐Ni and pyrrole‐Cu particles by using iron (III) chloride. The composites have been characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and magnetic susceptibility techniques. Conductivity measurements of samples were taken using four‐probe devices. The PPy/Ni(0) and PPy/Cu(0) nanocomposites doped with different acids exhibited higher conductivity values than those of homopolymers. Among all samples, Ni/PPy‐H₃BO₃ has the highest conductivity (1.42 S cm^?1). Homopolymers and composites showed a stable and increasing conductivity with increasing temperature, except Ni(0). We observed that from TGA analysis of polymers, metal composites of PPy synthesized in two different media are more stable than those of PPy‐CH₃COOH and PPy‐H₃BO₃. The magnetic susceptibility values of homopolymers and Cu are negative, whereas the other samples are positive. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Electronic properties of polypyrrole based TiO2 nanofiber composite

In this work, Polypyrrole (PPy), Titanium dioxide nanofiber (TiO₂‐nf) are prepared by oxidative polymerization and hydrothermal process respectively. The PPy/TiO₂‐nf composite is prepared by in situ oxidative polymerization in the presence of pyrrole monomer and TiO₂‐nf. The nanocomposite and TiO₂‐nf are then characterized by scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy (EDX) techniques and XRD studies. Dielectric studies of PPy/TiO₂‐nf composite is carried out in the frequency range of 1 KHz‐3 MHz at varying temperature and it shows anomalous behavior at 1MHz, where its value reaches to its minimum value of 13 at room temperature and this dip remains even at higher temperature. Impedance study is used to understand the grain and grain boundary effects of the material; frequency dependent ac conductivity has two regions separated at 1MHz, which is being explained by hopping conduction and Maxwell‐Wagner type mechanism, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40036.     

Conducting polyaniline‐titanium dioxide nanocomposites prepared by inverted emulsion polymerization

Conducting polyaniline (PAni)‐titanium dioxide (TiO₂) nanocomposites have been synthesized by the inverted emulsion polymerization method. Aqueous mixtures of aniline, a free‐radical oxidant, and/or TiO₂ nanoparticles (∼25 nm in diameter; mixture of anatase and rutile) are utilized to synthesize the hybrid nanocomposites. The polymerization is carried out in an organic solvent (chloroform, CHCl₃) in the presence of a protonic acid (hydrochloric acid, HCl) as a dopant and an emulsifier (cetyl trimethylammonium bromide). The resultant PAni‐TiO₂ nanocomposites are characterized with their structural, morphological, conducting, and optical properties. SEM and TEM images represent the PAni‐TiO₂ nanocomposites with the diameter range of 50–200 nm. Electrical conductivities are checked by standard four‐point probes method and found to be 0.38 S/cm for bulk PAni and 0.11 S/cm for PAni‐TiO₂ nanocomposites. UV–visible absorption shows two electronic bands at about 320 and 596 nm for bulk PAni and the blue‐shifted bands with the intensity changes due to the formation of PAni‐TiO₂ composites. Thermogravimetric analysis reveals that the composites have a higher degradation temperature than the PAni alone. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Synthesis and characterization of polypyrrole dodecylbenzenesulfonate‐titanium dioxide nanocomposites

Nanocomposites of polypyrrole dodecylbenzenesulfonate‐titanium dioxide have been prepared from a colloidal solution of titanium dioxide (TiO₂) nanoparticles. The DC conductivity of samples with different concentrations of TiO₂ has been investigated under dark and light. The doping effect of TiO₂ has been characterized and evaluated by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and X‐ray diffraction. TEM shows that TiO₂ nanoparticles have strong effects on the morphology of composites, and conductivity measurements show that the conductivity first increases and then decreases as the percentage of TiO₂ is increased in the composites exhibiting a maximum in conductivity at about 20 wt % of TiO₂. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of SiO2 and TiO2 nanoparticle on the properties of phenyl silicone rubber

Two types of nanoparticles TiO₂ and SiO₂ treated with silane coupling agents were incorporated into phenyl silicone rubber at a low concentration (≤1.0%) and cured by the room temperature vulcanized method. The results showed that treated TiO₂ or SiO₂ nanoparticles improved the ultraviolet (UV)‐shielding ability and enhanced the visible transmittance of the phenyl silicone rubber, compared with their respective untreated particles. Moreover, when comparing treated nanoparticles, TiO₂ was more responsible for augmenting the UV‐shielding ability of the phenyl silicone rubber, while SiO₂ played a more important role in increasing the transmittance of visible light. Low levels of nanoparticles reduced the dielectric constant of the nanocomposite; however, on reaching a critical concentration, increasing the nanoparticle content had the opposite effect. The thermal conductivity of nanocomposites increased linearly with the amount of treated nanoparticles, while SiO₂ nanocomposites exhibited better thermal conductivity than those of TiO₂. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42806.