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PANI-co-PIN/Cu–Al2O3 nanocomposites synthesised via in situ polymerization showed excellent electrical and NH3 gas sensing properties.

This work focused on the preparation of biopolymer blend nanocomposites from chitin (CT) and cashew tree gum (CTG) with different contents of copper sulphide nanoparticles (CuS) by solution casting method. The formation of nanocomposites have been characterized by FT infrared (FTIR), UV spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), thermogravimetry (TGA), differential scanning calorimetry (DSC) and impedance analysis. The characteristic absorption of nanoparticles in the FTIR spectra and shift in UV spectra of blend composites revealed the strong interaction between CuS nanoparticles and the polar segments of CT/CTG blend. With the increase in dosage of nanoparticles, a decrease in amorphous domains has been noted in the XRD scans. The uniform distribution of nanoparticles in CT/CTG network has been confirmed by the SEM analysis. HRTEM of the blend composites reveals the formation of hemispherical nanoparticles with a diameter of 15–30 nm. The glass transition temperature of blend composites increased with the addition of nano-CuS in the polymer matrix. Compared to the pure CT/CTG blend, the prepared nanocomposite showed higher thermal stability. Mechanical properties such as tensile strength and hardness of the blend nanocomposites were greatly enhanced by the reinforcement of CuS into the CT/CTG matrix. The AC conductivity and dielectric properties of the nanocomposites increased with the concentration of fillers and the magnitude of these properties was higher than the pure polymer blend.

Metal oxide nanofillers are a special type of additives in rubber composites that impart special qualities such as thermal resistance, tensile strength, electrical conductivity and heat capacity to rubbers. The heat conductivity of metal oxide through the rubber matrix reduces the vulcanization time of the rubber nanocomposites. Hence, the present work focused on the enhancement of these properties in natural rubber (NR) using zinc ferrite (ZnFe2O4) nanoparticles were prepared by a simple two-roll mill mixing technique. Structure, morphology, crystalline nature, cure characteristics, swelling, thermal and mechanical properties of the NR composites containing ZnFe2O4 were analysed in detail. FTIR and UV analysis proved the interaction of zinc ferrite with the macromolecular chain of NR. The XRD patterns of composite films revealed a decrease in amorphousness of NR with well-dispersed crystalline peaks of nanoparticles in the polymer. SEM images evidenced the morphological changes caused by dispersing zinc ferrite in the NR matrix. TEM analysis showed the uniform attachment of nanoparticles in the polymer. Glass transition temperature obtained from DSC was improved with the addition of zinc ferrite. The results from TGA showed that the presence of ZnFe2O4 in the polymer matrix greatly increases the thermal stability of NR. The metal oxide nanofiller significantly reduced the cure and scorch time of the NR composites. The mechanical properties of rubber nanocomposites showed that the addition of ZnFe2O4 improved their modulus, tensile strength, hardness, abrasion resistance and heat build-up, whereas the elongation at break and resilience decreases. The permeation and diffusion of nanocomposites were observed to be diminished with the size of penetrating solvents and also with the loading of filler. Overall, zinc ferrite nanoparticles could be used as a potential filler for improving the processability, mechanical strength, thermal stability and solvent resistance of natural rubber.

This study encompasses the synthesis, characterization, optical properties, thermal, mechanical, and electrical characteristics of a series of in situ polymerized poly (methyl methacrylate) (PMMA) with different contents of polyindole (PIN) composites. The formation of composites was characterized by FTIR, UV-visible, XRD, FE-SEM, AFM, DSC and TGA. Tensile testing techniques was used to determine mechanical properties such as tensile strength, modulus, hardness and impact strength of PMMA/PIN. Impedance spectroscopy was used to study the electrical properties of the prepared composites. The interaction between the NH moiety of indole and ester groups of PMMA was established through FTIR. The optical bandgap energy determined from UV spectroscopy shows a declining trend, whereas the refractive index grows significantly with the loading of indole up to 5 wt%. The decrease in broadness and intensity of the XRD peak confirmed the presence of an indole component in the PMMA matrix. The holes in the surface morphology of PMMA was changed into uniformly dispersed particles, confirming the dispersion of PIN in the PMMA matrix. The surface roughness obtained from AFM increases with the addition of PIN to PMMA. DSC measurements show that the glass transition temperature of the polymer increases with the inclusion of the indole moiety. TGA indicates that the addition of PIN has a positive effect on the thermal stability of PMMA/PIN composites. The results of mechanical testing showed an increase in Youngs modulus, tensile strength, and impact strength with the addition of PIN. The AC impedance results show an increase in the dielectric constant and conductivity of PMMA with the PIN addition. PMMA/PIN composites with high tensile strength, conductivity and dielectric constant can be used in the fabrication of optoelectronic devices and EMI shielding.

This work focused on the preparation of chlorinated nitrile rubber (Cl-NBR)/hydroxyapatite (HA) nanocomposites by an open two-roll mixing mill. The formation of nanocomposites was characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The dielectric properties and flame retardancy of polymer nanocomposites were analyzed with special attention to the loading of HA nanoparticles. Diffusion and permeation properties of petroleum solvents through the prepared Cl-NBR/HA composites were also investigated in detail as a function of filler content, different temperatures and nature of solvent. The incorporation of HA in Cl-NBR has been endorsed by FTIR analysis. The XRD showed the crystalline peaks of HA in the polymer chain. SEM images revealed that the nanoparticles were uniformed distributed in the polymer network with spherically shaped particles. TGA results indicated that the thermal stability of nanocomposites was remarkably higher than the pure Cl-NBR and the thermal stability increases with the loading of nanoparticles. The dielectric study observed a decreasing dielectric constant with increasing frequency, and the maximum property was obtained for 7 phr HA filling in Cl-NBR. The flame resistance of the polymer composites was greatly enhanced by the incorporation of nanoparticles. The diffusion, sorption and permeation constants were found to decreased with increase in HA content. The solvent uptake decreases with the size of the penetrant molecules, and the mechanism of transport of Cl-NBR composite was anomalous in nature. The enthalpy and entropy changes of the nanocomposites were analyzed from the diffusion data. The composite containing 7 phr HA sample showed higher dielectric properties and better solvent resistance properties.

The current article aims to develop poly (butyl methacrylate) (PBMA) nanocomposites with enhanced electrical and mechanical properties by incorporating neodymium oxide (Nd2O3) nanoparticles between the PBMA chains. The morphological, thermal and structural profiles of the PBMA nanocomposites reinforced with different loading of Nd2O3 nanoparticles were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The SEM images revealed that the morphology of the PBMA was significantly influenced by the insertion of Nd2O3. The uniform dispersion of Nd2O3 in the polymer composite was visible at 5 wt% loading of nano-filler. The main crystalline peaks of Nd2O3 nanoparticles in the amorphous PBMA structure were revealed by the X-ray diffraction analysis. The thermal stability of PBMA was greatly enhanced by the dispersion of Nd2O3 in the PBMA matrix. The tensile strength and elongation at break of the composites were measured and both results showed the enhanced mechanical properties of PBMA due to the reinforcement of Nd2O3 nanoparticles. The various parameters affecting the increased tensile strength of composite by the incorporation of nanoparticles were studied by different theoretical modeling. The electrical properties such as dielectric constant and the dielectric loss tangent (tan δ) of PBMA nanocomposites were enhanced with the addition of nanoparticles. Also, the DC conductivity of polymer composites was estimated and the applicability of different theoretical models for predicting the conductivity properties of PBMA/Nd2O3 nanocomposites were examined.

Novel elastomeric blend nanocomposites of chlorinated nitrile rubber (Cl-NBR) and chlorinated ethylene-propylene-diene rubber (Cl-EPDM) with different contents of nano-hydroxyapatite (HA) were prepared. The formation of blend nanocomposite was analyzed by FTIR, XRD, TEM, SEM and TGA. The fire resistance, dielectric behavior and diffusion of petroleum fuels through the blend membrane had been investigated as a function of nanoparticle loading. The FTIR revealed the absorption band of HA in the rubber blend indicated the effective interaction between HA nanofiller and the rubber blend. XRD plots indicated a reduction in amorphous region of rubber blend with the addition of nanoparticles. TEM and SEM images revealed the uniform dispersion of nanoparticles in the rubber blend. TGA results indicated that the thermal stability of rubber blend nanocomposite was higher than Cl-NBR/Cl-EPDM blend. Increased fire resistance of blend composites obtained from limiting oxygen index demonstrated that hydroxyapatite nanoparticles were served as an excellent fire-retardant additive for Cl-NBR/Cl-EPDM blend. Improvement in dielectric constant with the loading of nanoparticles indicated the reinforcement of blend matrix by the HA nanoparticles. The solvent uptake of blend nanocomposite decreased up to 7 phr HA-loaded sample. A decrease in solvent uptake was also observed with the increase in molecular size of the penetrant molecules. The mechanism of diffusion was anomalous in nature. Overall, the sample with 7 phr of HA-filled rubber blend showed a remarkable increase in dielectric properties, flame resistant and minimum solvent uptake.

Thermoplastic nanocomposites based on poly (butyl methacrylate) (PBMA) with various contents of neodymium oxide (Nd2O3) nanoparticles were synthesized through one-step free radical polymerization method. The structural, morphological and thermal properties of the nanocomposites were studied by Fourier transform infrared (FTIR) spectroscopy, ultraviolet (UV)–visible spectroscopy, high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and thermogravimetry and differential scanning calorimetry (DSC). The effect of different volume fraction of Nd2O3 nanoparticles on temperature-dependent AC conductivity of polymer nanocomposites was also analysed. The FTIR and UV spectra confirmed the incorporation of Nd2O3 nanoparticles in PBMA chain through the shift in characteristic absorption bands of nanocomposite compared to pure PBMA. TEM images indicated that Nd2O3 nanoparticles were sheathed by PBMA chain. The SEM images revealed better compatibility between the PBMA and Nd2O3 nanoparticles. The thermal transition studied by DSC showed an enhanced glass transition temperature of PBMA by the inclusion of Nd2O3 nanoparticles. Similarly, the thermal degradation of the composite was elevated by the insertion of nanoparticles. The AC conductivity of nanocomposite was higher than pure PBMA and the electrical conductivity increased with the temperature and frequencies. The activation energy and exponential values of the composite revealed that the system follows small polaron hopping mechanism.

Nitrile rubber (NBR) has been extensively used in high oil resistance application such as in automotive seals and gaskets. Due to the poor mechanical strength of NBR, the performance of these products undergoes deterioration when it is in contact with hot oils and solvents. The aim of the present work is to investigate the molecular transport of petroleum fuels and oil through chlorinated NBR (Cl-NBR) with respect to different contents of chlorine. It also focuses on the effect of chlorine content on the alternating current (AC) conductivity and dielectric properties of Cl-NBR for flexible electronic applications. The transport characteristics of petroleum fuels through the NBR and Cl-NBR membranes have been studied by a simple sorption gravimetric analysis in the temperature range 27–50°C. The diffusion results have been explained in terms of the size of liquid molecules and the diffusion mechanism was found to follow the anomalous trend. The diffusion, sorption, solvent uptake, and permeation constants were investigated and were found to decrease with increase in the level of chlorine content in NBR matrix. The activation energy for diffusion and permeation processes were increased and reached maximum value for Cl-NBR (22% Cl content). The oil resistance property of Cl-NBR was significantly higher than pure NBR. The swelling of Cl-NBR in ASTM oil was three times lower than NBR. The electrical conductivity and dielectric properties of NBR was found to be increased with the increase in chlorine content of NBR. NBR showed the AC conductivity value of 7.24 S cm−1 at 106 Hz, while the Cl-NBR with 24% chlorine showed the conductivity value of 4.69 S cm−1. The higher AC conductivity and dielectric properties, solvent, and oil resistance of Cl-NBR than that of NBR suggests that the Cl-NBR can be used as multifunctional materials for flexible nano-electronic devices and high-performance oil-resistant applications.

In this research, the effect of cerium dioxide (CeO2) nanoparticles on electrical properties of poly(butyl methacrylate) (PBMA) has been investigated. Polymer nanocomposites reinforced with variable contents of CeO2 nanoparticles (3, 5, 7 and 10 wt%) were fabricated by an in situ polymerization method. The formation of nanocomposites was analyzed by FTIR, XRD, SEM and TEM analysis. Also, the AC and DC conductivities of CeO2 nanoparticles-reinforced PBMA were systematically studied with respect to different loadings of CeO2 fillers. The FTIR, XRD and morphological studies revealed that the nanoparticles were well inserted and uniformly dispersed into the macromolecular chain of PBMA. The AC conductivity of PBMA/CeO2 composite increases not only with the loading of nanoparticles but also with the temperature of the system. The activation energy determined from AC electrical conductivity was found to decrease with the frequency and temperature. DC conductivity of the nanocomposites was increased with the insertion of nanoparticles into PBMA. The DC conductivity of all the composites was greater than pure PBMA. The applicability of different theoretical models such as Scarisbrick, Bueche and McCullough equations was compared with the experimentally determined DC conductivity of PBMA/CeO2 nanocomposites. These models fail to explain the conductivity of polymer composite in the entire loading of fillers. Hence, a new theoretical model is proposed in this study and it shows good agreement with the experimentally observed conductivity values.

This paper describes the preparation, characterization and electrical properties of polyindole (PIN)/phenothiazine (PTZ) blend nanocomposite with different contents of nickel oxide (NiO) nanoparticles. Ultraviolet–Visible spectroscopy and Fourier transform infrared spectroscopic characterizations were carried out to investigate the extent of chemical interactions between PIN/PTZ blend and NiO nanoparticles. Morphological studies carried out using scanning electron microscopy and transmission electron microscopy showed the formation of globular composite particles with a size in 15–25 nm range. X-ray diffraction study of the resultant composites reveals the distribution of sharp crystalline peak of NiO in the blend. Thermogravimetric results confirmed that the rate of degradation of the composite was lower as compared to the pure polymer blend and the thermal stability of the blend increases with the loading of nanoparticles. An investigation of the electrical properties of the prepared nanocomposites revealed that AC conductivity, dielectric constant and dielectric loss of composite increased in proportion to the increase in NiO loading. Current–voltage measurements (I–V curve) showed that the PIN/PTZ/NiO composites have much higher electrical conductivity than pure polymer blend. The gas sensing measurement for PIN/PTZ blend with different contents of NiO nanoparticles toward ammonia gas were investigated.

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.

This work focuses on the preparation of styrene–butadiene rubber (SBR)/zinc sulfide (ZnS) nanocomposites using a simple and inexpensive two-roll mill mixing technique. The structural, morphological and thermal properties of the nanocomposites were analyzed by FT-IR, UV–visible spectroscopy, XRD, SEM and DSC measurements. The results of the spectroscopic studies revealed the interaction of ZnS nanoparticles with SBR through the shift in the peaks of UV and FT-IR spectra. The XRD and SEM studies showed that the nanoparticles were well inserted into the macromolecular structure of SBR. The glass transition temperature of the composites increased with the addition of nanoparticles. The dielectric constant of nanocomposite with different loading of nanoparticles was carried out in the frequency range 100–106 Hz. The dielectric properties of nanocomposites were higher than that of pure SBR. In addition, the diffusion and transport properties of organic solvents through SBR/ZnS nanocomposites were studied in detail as a function of ZnS content. The polymer–solvent interaction parameter, enthalpy and entropy of sorption data were estimated from the transport properties. The high dielectric constant of these nanocomposites infers that ZnS is one of the ideal nanofiller for the development of high-k materials for flexible energy storage applications.

The nonlinear optical properties of phenothiazine-iodine (PTZ-I) charge transfer complexes (CTC) in three different proportions were investigated by z-scan set up using Nd: YAG laser at 532 nm wavelength, 7 ns pulse width and 10 Hz repetition rate as excitation source. The interaction between phenothiazine and iodine was analysed using FTIR spectroscopy. The morphological changes after the formation of CTC were observed with the help of scanning electron microscopy and optical microscopy. The CTC system displayed an absorption in the UV-Visible region, which is attributed to the charge transfer between constituents. Optical nonlinearity was observed to be maximum when the molar ratio between phenothiazine and iodine is 1:1, and it strongly depends on the electron donor-acceptor proportion. Optical limiting threshold values of the studied samples are comparable to many reported values. The excellent nonlinear optical properties exhibited by PTZ-I CTC make them promising candidates in nonlinear optical applications.

Among the unique properties of polymer nanocomposites, electrical conductivity deserves a prominent place due to their wide applications in conducting adhesive, electromagnetic shielding and sensors. The present work focuses on the effect of cerium-doped titanium dioxide (Ce-TiO2) nanoparticles on the conductivity studies of poly (n-butyl methacrylate), or PBMA, nanocomposites at different temperatures. The frequency-dependent alternating current (AC) electrical conductivity of PBMA/Ce-TiO2 nanocomposites has been found to increase with increase in temperature and the concentration of Ce-TiO2 nanoparticles. The activation energy calculated from the AC electrical conductivity has been found to decrease with frequency and increasing temperatures. The frequency exponent factor also showed a decrease with frequency, indicating the hopping conduction in the nanocomposites. The maximum AC conductivity has been observed for the composites with 7 wt.% sample. The direct current (DC) conductivity of PBMA/Ce-TiO2 composites was also enhanced with the addition of Ce-TiO2 nanoparticles. Experimental and theoretical investigations based on Scarisbrick, Bueche, McCullough and Mamunya modeling were undertaken to understand the observed DC conductivity differences induced by the addition of Ce-doped TiO2 nanoparticles to PBMA matrix. The experimental conductivity showed good agreement with the theoretical conductivity observed using the Mamunya model.

Polypyrrole (PPy)/silver doped titanium dioxide (Ag-TiO2) nanocomposites were prepared using simple and inexpensive in situ chemical oxidative polymerisation. The nanocomposites were characterised by Fourier transform infrared (FTIR), UV-Vis spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), alternating current (AC) and direct current (DC) conductivity measurements. Furthermore, the ammonia gas sensing properties of PPy and its nanocomposites were explored thoroughly. The FTIR spectrum confirmed the formation of a polymer nanocomposite when the characteristic bands of the PPy shifted to a lower wavenumber region. The UV-Vis spectrum revealed that all the absorption peaks of the composite were shifted to a higher wavelength in comparison with PPy. The shifts in absorption peaks were due to the strong interfacial interaction between the nanoparticles and polymer chain. SEM images showed that the nanoparticles were well shaped spherical particles with the uniform dispersion in the PPy. XRD results revealed that the crystallinity of the nanocomposite increased with an increase in concentration of nanoparticles. TGA analysis showed that the thermal stability of the nanocomposite was enhanced compared to pure PPy. From the DSC analysis, it was clear that the glass transition temperature of the nanocomposite increased when the concentration of metal oxide nanoparticles was augmented. The fabricated composites showed excellent sensitivity and fast response to ammonia gas at room temperature. The electrical conductivity, dielectric constant and dissipation factor of the nanocomposites significantly increased with an increase in the concentration of metal oxide nanoparticles in the PPy matrix.

The enhanced nonlinear optical properties of phenothiazine-iodine (PTZ-I) charge transfer complex (CTC) on composite formation with ZnS/ZnSe nanostructures are reported. The interaction between the components was confirmed by the FTIR spectra. Structural and morphological changes on nanocomposite formation were analyzed by scanning electron microscopy and X-ray diffraction spectra. The absorption and emission features of both the nanocomposites and their constituent components were studied. Nonlinear optical properties of all the samples in nanosecond regime were investigated by the Z-scan technique using Nd: YAG laser with 532 nm wavelength and 7 ns pulse width. The optical nonlinearity of PTZ-I CTC was found to be improved considerably on composite formation and the new systems can be proposed as excellent candidates for photonic devices. Enhanced optical nonlinearity of the composites could be attributed to charge/energy transfer mechanism between PTZ-I CTC and the nanostructures.

This study focused on the fabrication of poly(n-butyl methacrylate) (PBMA) nanocomposites with various concentrations of cerium-doped titanium dioxide (Ce–TiO2) nanoparticles via in situ polymerization technique. The structural characterization and the material properties of all the composites were analyzed by UV–visible, FTIR, XRD, SEM, DSC, TG, and tensile strength measurements. The UV–visible and FTIR studies confirmed the effective inclusion of Ce–TiO2 nanoparticles into the PBMA matrix. The change in amorphous morphology of PBMA to a crystalline structure was observed from the XRD pattern. The SEM morphology revealed the attachment of nanoparticles in the polymer matrix. The inclusion of Ce–TiO2 nanoparticles enhanced the glass transition temperature, and thermal stability of the PBMA matrix was revealed from DSC and TG, respectively. The tensile strength of PBMA was greatly enhanced by the addition of Ce–TiO2 nanoparticles. The AC conductivity, dielectric constant, and dielectric loss studies were also performed in the frequency range 102–106 Hz, and it was observed that addition of Ce–TiO2 nanoparticles greatly enhanced the electrical properties of PBMA. The change in dielectric constant with the addition of nanoparticles was correlated with a theoretical modeling study. This work also extended to study the role of Ce–TiO2 nanoparticles in the reinforcing mechanism of the nanocomposite by comparing the actual tensile strength of the composite with different theoretical modeling. The high dielectric constant and tensile strength of composite are beneficial in designing lightweight and highly efficient nanoelectronic materials based on the family of polybutyl acrylates.

The present work investigates the influence of loading of manganous tungstate (MnWO4) nanoparticles on the rheometric processing characteristics, crystallinity, morphology, glass transition temperature, oil resistance, transport behavior, mechanical and electrical properties of chlorinated styrene butadiene rubber (Cl-SBR). The reduction in the overall amorphous nature of Cl-SBR has been observed with the addition of nanofillers, as confirmed by X-ray diffraction studies. The maximum uniform dispersion of nanofiller in Cl-SBR has been noted at 7-phr loading, while at higher loadings, filler agglomerations have been observed in the scanning electron micrographs. An increase in the glass transition values with the addition of nanoparticles proves the reduced flexibility of the elastomer systems. The reduction in optimum cure time with the loading of nanoparticles has been found to be beneficial as far as the production rate of articles using these nanocomposites is concerned. Among the mechanical properties studies, tensile strength, modulus and tear strength registered an increase in the loading of nanofillers up to 7 phr due to the reinforcement of elastomer by the nanoparticles. The AC conductivity of Cl-SBR/MnWO4 nanocomposite increased with increasing the frequency and loading of nanoparticles. It is important that at 7-phr loading of nanoparticles, the conductivity value reaches the range of semiconductors. The superior reinforcement of Cl-SBR with 7-phr nanoparticles has been supported by the results of solvent diffusion and transport studies also. Values of solvent sorption parameters such as the energy of activation and enthalpy of diffusion have been found to be complementary to each other supporting the results obtained earlier. The reinforcing ability of the nanoparticles in Cl-SBR has been correlated with Lorentz and Park model.