Browsing by Author "Kalathi, J.T."

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A facile synthesis of halloysite nanotubes based polymer nanocomposites for glass coating application
(Elsevier Ltd, 2018) Buruga, K.; Kalathi, J.T.
Halloysite-based polymethyl methacrylate (HNT-PMMA) and polystyrene (HNT-PS) nanocomposite coatings for glasses were synthesized by ultrasound-assisted solution blending method. The coatings were then dip-coated on four different types of soda-lime glass and the spectral, mechanical properties of the coated glasses were analyzed. The coated glass samples displayed a better scratch resistance and surface hydrophobicity, compared to uncoated samples, without any significant changes in their inherent spectral properties. The thermal and mechanical properties (Tg and tensile strength) of the nanocomposites were also enhanced compared to neat polymers. The improvement in thermal and scratch resistance of the coatings is ascribed to the inclusion of halloysite nanotubes (HNTs) in the polymer matrix. Hence, HNT-based PMMA/PS nanocomposite coatings can be effectively used for glasses in automotive and architectural applications. © 2017 Elsevier B.V.
A review on functional polymer-clay based nanocomposite membranes for treatment of water
(Elsevier B.V., 2019) Buruga, K.; Song, H.; Shang, J.; Bolan, N.; Kalathi, J.T.; Kim, K.-H.
Water is essential for every living being. Increasing population, mismanagement of water sources, urbanization, industrialization, globalization, and global warming have all contributed to the scarcity of fresh water sources and the growing demand of such resources. Securing and allocating sufficient water resources has thus become one of the current major global challenges. Membrane technology has dominated the field of water purification due to its ease of usage and fabrication with high efficiency. The development of novel membrane materials can hence play a central role in advancing the field of membrane technology. It is noted that polymer-clay nanocomposites have been used widely for treatment of waste water. Nonetheless, not much efforts have been put to functionalize their membranes to be selective for specific targets. This review was organized to offer better insights into various types of functional polymer and clays composite membranes developed for efficient treatment and purification of water/wastewater. Our discussion was extended further to evaluate the efficacy of membrane techniques employed in the water industry against major chemical (e.g., heavy metal, dye, and phenol) and biological contaminants (e.g., biofouling). © 2019 Elsevier B.V.
CFD modeling and simulation of catalytic pyrolysis of heavy oils in a tapered fluidized bed reactor
(Walter de Gruyter GmbH, 2025) Gowtham, C.; Kalathi, J.T.
A fluidized bed reactors (FBRs) have been widely used for catlytic cracking, combustion, gasification, pyrolysis and other applications. However, to improve the performance of FBRs, a better understanding of its flow behaviour is required, especially when multiphases are present. In this research work, we have studied the hydrodynamics and performance of FBR for the catalytic pyrolysis of heavy oil into lighter fractions using a Computational Fluid Dynamics (CFD) approach. The eight-lump kinetic model was used to model the pyrolysis of heavy oil. The effect of riser geometry on the pyrolysis was investigated using a 2D transient Eulerian and the granular flow models. The fluid flow behaviour in tapered-in and tapered-out reactors (risers) for two different tapering angles (1° and 2°), conventional cylindrical reactor and pyrolysis at two different temperatures (600°C and 700°C) are studied, and the results are compared. The yield of pyrolysis products from the cylindrical riser is validated using previous mathematical models and experimental results from the literature. The results of the present CFD model for the cylindrical riser are in concert with the experimental results reported in the literature. The yields of light olefins, ethene, propene and butene are 48 wt%, 18 wt%, 34 wt%, respectively, at 700° as higher temperature favours a better yield of pyrolysis products. The same CFD model is extended to study the tapered riser geometries, and the simulation results support that the tapered-in geometry favours the pyrolysis, resulting in the higher conversion of gas oil compared to cylindrical riser due to increased residence time of solids (catalysts) and hence better contact with the fluid phase for the reactions. © 2025 Walter de Gruyter GmbH, Berlin/Boston.
Effects of Solvents on Structure, Morphology and Thermal Stability of Polystyrene-HNTs Nanocomposites by Ultrasound Assisted Solution Casting Method
(Elsevier Ltd, 2017) Buruga, K.; Kalathi, J.T.
Polymer-clay nanocomposites are extensively investigated as they are economical in comparison with other nanofillers and drastically enhances various physical and engineering properties of polymers. Among various clays used for polymer-nanocomposites, Halloysite nanotubes (HNTs) have gained tremendous attention as they have unique structure and properties. In the present work we have successfully synthesised polystyrene-HNT nanocomposites by ultrasound assisted solution intercalation method. In this method solvent plays a very crucial role in enhancing the overall properties of resultant nanocomposites as arrangement of filler in the polymer matrix depends upon how well the solvent is able to disperse filler which inturn enhances polymer properties. Hence in this work solvents toluene, benzene, chloroform, dichoromethane (DCM), tetrahydrofuran (THF) and carbontetrachloride (CCl4) were used for synthesis of nanocomposites and effect of these solvent on structure, morphology and thermal stability of nanocomposites was investigated. As per the characterization analysis, toluene was found to be the best solvent for synthesis of nanocomposites with enhanced properties and use of ultrasound aided in uniform distribution of clay in polymer matrix. Increase in basal spacing on sonication was revealed by x-ray diffraction (XRD) analyses. Scanning electron microscopy (SEM) results revealed uniform dispersion of filler inside the matrix on using acoustic cavitation as it promotes proportionate distribution of filler into the polymer matrix. Fourier transform and infrared (FT-IR) results confirmed encapsulation of HNTs into polymer. Differential scanning calorimetry (DSC) reports illustrated increase in glass transition temperature (Tg) on incorporating HNTs. Â© 2017 Elsevier Ltd.
Fabrication of ?-MPS-Modified HNT PMMA Nanocomposites by Ultrasound-Assisted Miniemulsion Polymerization
(2018) Buruga, K.; Kalathi, J.T.
Halloysite nanotubes (HNTs) were modified with ?-methacryloxypropyltrimethoxysilane (?-MPS) to improve their interaction with the polymer, and the modified HNTs (MHNTs) were subsequently used for the synthesis of MHNT polymethylmethacrylate (PMMA) nanocomposites by miniemulsion polymerization assisted by ultrasound. Reduced agglomeration of HNTs due to modification with ?-MPS was evident from scanning electron microscopy analysis. Modification of HNTs and exfoliation of MHNTs in the polymer nanocomposite were confirmed by the presence of their respective characteristic peaks in Fourier-transform infrared spectra and x-ray diffraction patterns. Transmission electron microscopic analysis showed that the surface of the MHNTs differed significantly from that of unmodified HNTs. MHNT PMMA nanocomposite exhibited significantly higher glass-transition temperature (Tg) compared with neat PMMA or unmodified HNT PMMA nanocomposite. Hence, such modification of HNTs along with miniemulsion polymerization assisted by ultrasound is a promising approach to achieve better dispersion of HNTs in the polymer and to obtain nanocomposites with enhanced properties. 2018, The Minerals, Metals & Materials Society.
Fabrication of ?-MPS-Modified HNT–PMMA Nanocomposites by Ultrasound-Assisted Miniemulsion Polymerization
(Minerals, Metals and Materials Society 184 Thorn Hill Road Warrendale PA 15086, 2018) Buruga, K.; Kalathi, J.T.
Halloysite nanotubes (HNTs) were modified with ?-methacryloxypropyltrimethoxysilane (?-MPS) to improve their interaction with the polymer, and the modified HNTs (MHNTs) were subsequently used for the synthesis of MHNT–polymethylmethacrylate (PMMA) nanocomposites by miniemulsion polymerization assisted by ultrasound. Reduced agglomeration of HNTs due to modification with ?-MPS was evident from scanning electron microscopy analysis. Modification of HNTs and exfoliation of MHNTs in the polymer nanocomposite were confirmed by the presence of their respective characteristic peaks in Fourier-transform infrared spectra and x-ray diffraction patterns. Transmission electron microscopic analysis showed that the surface of the MHNTs differed significantly from that of unmodified HNTs. MHNT–PMMA nanocomposite exhibited significantly higher glass-transition temperature (Tg) compared with neat PMMA or unmodified HNT–PMMA nanocomposite. Hence, such modification of HNTs along with miniemulsion polymerization assisted by ultrasound is a promising approach to achieve better dispersion of HNTs in the polymer and to obtain nanocomposites with enhanced properties. © 2018, The Minerals, Metals & Materials Society.
A facile synthesis of halloysite nanotubes based polymer nanocomposites for glass coating application
(2018) Buruga, K.; Kalathi, J.T.
Halloysite-based polymethyl methacrylate (HNT-PMMA) and polystyrene (HNT-PS) nanocomposite coatings for glasses were synthesized by ultrasound-assisted solution blending method. The coatings were then dip-coated on four different types of soda-lime glass and the spectral, mechanical properties of the coated glasses were analyzed. The coated glass samples displayed a better scratch resistance and surface hydrophobicity, compared to uncoated samples, without any significant changes in their inherent spectral properties. The thermal and mechanical properties (Tg and tensile strength) of the nanocomposites were also enhanced compared to neat polymers. The improvement in thermal and scratch resistance of the coatings is ascribed to the inclusion of halloysite nanotubes (HNTs) in the polymer matrix. Hence, HNT-based PMMA/PS nanocomposite coatings can be effectively used for glasses in automotive and architectural applications. 2017 Elsevier B.V.
High-Intensity Ultrasound-Assisted Low-Temperature Formulation of Lanthanum Zirconium Oxide Nanodispersion for Thin-Film Transistors
(American Chemical Society service@acs.org, 2020) Pujar, P.; Madaravalli Jagadeeshkumar, K.K.; Naqi, M.; Gandla, S.; Cho, H.W.; Jung, S.H.; Cho, H.K.; Kalathi, J.T.; Kim, S.
The process complexity, limited stability, and distinct synthesis and dispersion steps restrict the usage of multicomponent metal oxide nanodispersions in solution-processed electronics. Herein, sonochemistry is employed for the in situ synthesis and formulation of a colloidal nanodispersion of high-permittivity (?) multicomponent lanthanum zirconium oxide (LZO: La2Zr2O7). The continuous propagation of intense ultrasound waves in the aqueous medium allows the generation of oxidant species which, on reaction, form nanofragments of crystalline LZO at ?80 °C. Simultaneously, the presence of acidic byproducts in the vicinity promotes the formulation of a stable as-prepared LZO dispersion. The LZO thin film exhibits a ? of 16, and thin-film transistors (TFTs) based on LZO/indium gallium zinc oxide operate at low input voltages (?4 V), with the maximum mobility (?) and on/off ratio (Ion/Ioff) of 5.45 ± 0.06 cm2 V-1 s-1 and ?105, respectively. TFTs based on the compound dielectric LZO/Al2O3 present a marginal reduction in leakage current, along with enhancement in ? (6.16 ± 0.04 cm2 V-1 s-1) and Ion/Ioff (?105). Additionally, a 3 × 3 array of the proposed TFTs exhibits appreciable performance, with a ? of 3-6 cm2 V-1 s-1, a threshold voltage of -0.5 to 0.8 V, a subthreshold swing of 0.3-0.6 V dec-1, and an Ion/Ioff of 1-2.5 (×106). © © 2020 American Chemical Society.
Hybrid strategies for the treatment of latex-like wastewater from industries
(Elsevier, 2024) Raagasweatha, R.K.; Ahamed, A.; Mahalingam, H.; Kalathi, J.T.
Water, a vital part of daily life, is given special attention. Sadly, the wastewater generation rate is growing faster than its recycling rate due to various anthropogenic activities. The need for innovations in treating wastewater to meet freshwater requirements encourages the application of different advanced techniques in wastewater treatment. The advanced oxidation process, a tertiary treatment technique, has proven successful for many industrial effluent treatments. This chapter discusses the use of Fenton’s oxidation coupled with ultrasonication (US) as an efficient treatment for treating industrial wastewater containing emulsion polymers. The predominant presence of emulsion polymers in the untreated wastewater from industries, such as coatings and dispersions, creates a latex-like wastewater with characteristics similar to the latex wastewater produced in the rubber processing industries. This type of wastewater is typically characterized by very high TSS and COD values, thus making it impossible for conventional wastewater treatment plants to successfully reduce the COD/BOD values below acceptable discharge limits. In this chapter, an attempt is made to treat industrial wastewater samples containing emulsion polymers by combining sonolysis and Fenton oxidation. Photo-Fenton oxidation (PFO) and US techniques were carried out in different combinations, and the best COD reduction of ~97% was achieved by a combination featuring an initial 30min US (36kHz, 500W) followed by PFO (40min) and simultaneous US (36kHz) and PFO (40min). This corresponds to approximately 50% reduction in treatment time which can be deployed for treating latex-like wastewater in industries, whereas a COD reduction of 92% is achieved with PFO alone in 70min. However, the initial rate of COD reduction is more prominent with the combination of sonication. Hybrid processes such as US-PFO could be viable and effective options for achieving the best results in the treatment of industrial wastewater. © 2025 Elsevier Ltd. All rights reserved.
Interface Dominated Dielectric Response of PS-Fe3O4 Patchy Microspheres
(2019) Kishor, Kumar, M.J.; Kalathi, J.T.
Polymeric-inorganic interface plays a vital role in enhancing dielectric properties of patchy microspheres, Janus particles, and nanocomposites. We performed the computational modeling and simulations along with experiments to understand the phenomena behind the improved dielectric permittivity of polystyrene-iron oxide (PS-Fe3O4) patchy microspheres. We addressed the fundamental insights into the role of the interfacial region on the dielectric properties. Based on the experimental outcomes and computational simulations on dielectric behavior including polarization and electric field formation, we propose a new mechanism of charge buildup at the interface. Computational results reveal that the creation of interface bound-charges at the inorganic-polymeric interface is responsible for the improved dielectric properties. We also fabricated PS-Fe3O4 patchy microspheres by Pickering emulsion polymerization using Fe3O4 particles as a solid stabilizer. The microstructure, composition, morphology, dielectric, and thermal properties of the synthesized patchy PS-Fe3O4 particles were investigated. The dielectric permittivity (k) of the neat PS increased from ?2.9 to ?14.8 after decorating with Fe3O4 particles. Impedance response of the patchy microspheres shows that the interface of PS-Fe3O4 stores more charges than bulk PS-Fe3O4. The dielectric behavior of patchy microspheres can be engineered by tuning the shape and position of the patches. The present studies on polymer-inorganic interface provide some insights into the mechanisms that control dielectric permittivity and nonlinear conduction in an applied electric field. Copyright 2019 American Chemical Society.
Interface Dominated Dielectric Response of PS-Fe3O4 Patchy Microspheres
(American Chemical Society service@acs.org, 2019) Kishor Kumar, M.J.; Kalathi, J.T.
Polymeric-inorganic interface plays a vital role in enhancing dielectric properties of patchy microspheres, Janus particles, and nanocomposites. We performed the computational modeling and simulations along with experiments to understand the phenomena behind the improved dielectric permittivity of polystyrene-iron oxide (PS-Fe3O4) patchy microspheres. We addressed the fundamental insights into the role of the interfacial region on the dielectric properties. Based on the experimental outcomes and computational simulations on dielectric behavior including polarization and electric field formation, we propose a new mechanism of charge buildup at the interface. Computational results reveal that the creation of interface bound-charges at the inorganic-polymeric interface is responsible for the improved dielectric properties. We also fabricated PS-Fe3O4 patchy microspheres by Pickering emulsion polymerization using Fe3O4 particles as a solid stabilizer. The microstructure, composition, morphology, dielectric, and thermal properties of the synthesized patchy PS-Fe3O4 particles were investigated. The dielectric permittivity (k) of the neat PS increased from ?2.9 to ?14.8 after decorating with Fe3O4 particles. Impedance response of the patchy microspheres shows that the interface of PS-Fe3O4 stores more charges than bulk PS-Fe3O4. The dielectric behavior of patchy microspheres can be engineered by tuning the shape and position of the patches. The present studies on polymer-inorganic interface provide some insights into the mechanisms that control dielectric permittivity and nonlinear conduction in an applied electric field. © © 2019 American Chemical Society.
Investigation on the dielectric performance of PVDF-HFP/LZO composites
(Elsevier Ltd, 2020) M J, K.K.; Kalathi, J.T.
The energy storage density of the film capacitor is crucial for optoelectronic devices. Among various dielectrics, polyvinylidene-fluoride-co-hexafluoropropylene (PVDF-HFP) copolymer is widely preferred due to its inherent high dielectric constant and breakdown strength. However, the low energy storage density and high dielectric loss (tan ?) of PVDF-HFP remains challenging in the present scenario. In this work, we demonstrated how to improve the dielectric constant and energy density of PVDF-HFP with low dielectric losses by formulating PVDF-HFP/Lanthanum Zirconium Oxide (LZO) composite ink at low temperature. We performed the computational modeling of the thin-film capacitor, consisting of PVDF-HFP/LZO as a dielectric layer, to find the optimum LZO content for achieving a high energy density. A computational model of the film capacitor and dielectric shielding was built with PVDF-HFP/LZO composites having a different LZO content to understand its effect on the electric field distribution, polarization, and energy storage density. We compared the dielectric properties of the PVDF-HFP/LZO thin-film capacitor predicted by simulations with the experimental values measured by impedance analysis. The optimum LZO content in PVDF-HFP was determined as 15 vol% to achieve a high energy storage density of 15.8 J/cm3 at 545 MV/m breakdown strength with low dielectric losses. Dielectric constant and energy storage density of the PVDF-HFP/LZO15 composite film were nearly doubled compared to that of neat PVDF-HFP by keeping dielectric losses low. © 2020 Elsevier B.V.
Low-temperature sonochemical synthesis of high dielectric Lanthanum doped Cerium oxide nanopowder
(2018) Kishor, Kumar, M.J.; Kalathi, J.T.
Lanthanum (La) doped Cerium Oxide (CeO2) nanopowder was synthesized at a relatively lower temperature (70 C), without calcination in a simple, faster, and efficient way through sonochemical method. X-ray diffraction (XRD) results confirmed the formation of a cubic fluorite structure of nanocrystalline CeO2 and lattice deformation due to La-doping in CeO2. TEM analysis revealed that the size of La-doped CeO2 particles is in the range of 20?50 nm. In addition, selective area electron diffraction (SAED) and high-resolution TEM (HRTEM) analyses portrayed the nano-crystallinity, lattice fringe pattern, and d-spacing details of La-doped CeO2 powder. Lanthanum doping in CeO2 was further confirmed by a shift in Raman band towards the lower frequency (from 464 cm?1 to 457cm?1) along with peak intensity increase. Photoluminescence (PL) emission spectra showed that emission intensity of the La-doped CeO2 at 510 nm is increased due to oxygen vacancy mediated charge transfer. All these results confirm the successful doping of La in CeO2. The La-doped CeO2 powder possesses a high dielectric constant (?r) of 106 and a low dielectric loss (tan ?) of < 0.4 % at 1 kHz. The La-doped CeO2 finds potential applications on developing devices in the field of a thin film capacitor, transistors, and solid oxide fuel cells. 2018 Elsevier B.V.
Low-temperature sonochemical synthesis of high dielectric Lanthanum doped Cerium oxide nanopowder
(Elsevier Ltd, 2018) Kishor Kumar, M.J.; Kalathi, J.T.
Lanthanum (La) doped Cerium Oxide (CeO2) nanopowder was synthesized at a relatively lower temperature (70°C), without calcination in a simple, faster, and efficient way through sonochemical method. X-ray diffraction (XRD) results confirmed the formation of a cubic fluorite structure of nanocrystalline CeO2 and lattice deformation due to La-doping in CeO2. TEM analysis revealed that the size of La-doped CeO2 particles is in the range of 20?50 nm. In addition, selective area electron diffraction (SAED) and high-resolution TEM (HRTEM) analyses portrayed the nano-crystallinity, lattice fringe pattern, and d-spacing details of La-doped CeO2 powder. Lanthanum doping in CeO2 was further confirmed by a shift in Raman band towards the lower frequency (from 464 cm?1 to 457cm?1) along with peak intensity increase. Photoluminescence (PL) emission spectra showed that emission intensity of the La-doped CeO2 at 510 nm is increased due to oxygen vacancy mediated charge transfer. All these results confirm the successful doping of La in CeO2. The La-doped CeO2 powder possesses a high dielectric constant (?r) of 106 and a low dielectric loss (tan ?) of < 0.4 % at 1 kHz. The La-doped CeO2 finds potential applications on developing devices in the field of a thin film capacitor, transistors, and solid oxide fuel cells. © 2018 Elsevier B.V.
Nanoparticle Motion in Entangled Melts of Linear and Nonconcatenated Ring Polymers
(2017) Ge, T.; Kalathi, J.T.; Halverson, J.D.; Grest, G.S.; Rubinstein, M.
The motion of nanoparticles (NPs) in entangled melts of linear polymers and nonconcatenated ring polymers are compared by large-scale molecular dynamics simulations. The comparison provides a paradigm for the effects of polymer architecture on the dynamical coupling between NPs and polymers in nanocomposites. Strongly suppressed motion of NPs with diameter d larger than the entanglement spacing a is observed in a melt of linear polymers before the onset of Fickian NP diffusion. This strong suppression of NP motion occurs progressively as d exceeds a and is related to the hopping diffusion of NPs in the entanglement network. In contrast to the NP motion in linear polymers, the motion of NPs with d > a in ring polymers is not as strongly suppressed prior to Fickian diffusion. The diffusion coefficient D decreases with increasing d much slower in entangled rings than in entangled linear chains. NP motion in entangled nonconcatenated ring polymers is understood through a scaling analysis of the coupling between NP motion and the self-similar entangled dynamics of ring polymers. 2017 American Chemical Society.
Nanoparticle Motion in Entangled Melts of Linear and Nonconcatenated Ring Polymers
(American Chemical Society service@acs.org, 2017) Ge, T.; Kalathi, J.T.; Halverson, J.D.; Grest, G.S.; Rubinstein, M.
The motion of nanoparticles (NPs) in entangled melts of linear polymers and nonconcatenated ring polymers are compared by large-scale molecular dynamics simulations. The comparison provides a paradigm for the effects of polymer architecture on the dynamical coupling between NPs and polymers in nanocomposites. Strongly suppressed motion of NPs with diameter d larger than the entanglement spacing a is observed in a melt of linear polymers before the onset of Fickian NP diffusion. This strong suppression of NP motion occurs progressively as d exceeds a and is related to the hopping diffusion of NPs in the entanglement network. In contrast to the NP motion in linear polymers, the motion of NPs with d > a in ring polymers is not as strongly suppressed prior to Fickian diffusion. The diffusion coefficient D decreases with increasing d much slower in entangled rings than in entangled linear chains. NP motion in entangled nonconcatenated ring polymers is understood through a scaling analysis of the coupling between NP motion and the self-similar entangled dynamics of ring polymers. © 2017 American Chemical Society.
Performance of halloysite nanotube/poly(styrene-co-methylmethacrylate) nanocomposite coatings for the protection of soda-lime glass
(2019) Buruga, K.; Kalathi, J.T.
Polymer-based coatings for the protection of glass surfaces are used considerably in the construction and automotive industries. This research article focuses on the potential use of halloysite nanotubes (HNT)/Poly(Styrene-co-Methylmethacrylate) (PS-co-PMMA) nanocomposites as coatings for the protection of soda-lime glass. The effect of HNT content and coating thickness on the spectral properties of the glass, morphology, surface-wettability, and thermo-mechanical properties of the nanocomposite coatings were investigated and reported. The inherent spectral behavior of glass was not altered significantly by the coatings when the content of HNTs in coatings was ? 5 wt %. The coated glasses also exhibited a slight increase in the solar skin protection factor (SSPF), but notable improvement in the solar material protection factor (SMPF) when the HNT content was high in coatings. Thermogravimetric analysis (TGA) revealed that the HNT/PS-co-PMMA nanocomposite coatings possess excellent thermal stability compared to the neat copolymer. The surface wettability of coated glasses by water droplets decreased substantially due to coatings as evident from contact angle measurements. The HNT/PS-co-PMMA nanocomposites also displayed enhanced tensile strength and scratch resistance with increasing HNT content of coatings up to 5 wt%. Overall, the performance of the coated glass was enhanced by the coatings. 2018 Elsevier B.V.
Performance of halloysite nanotube/poly(styrene-co-methylmethacrylate) nanocomposite coatings for the protection of soda-lime glass
(Elsevier Ltd, 2019) Buruga, K.; Kalathi, J.T.
Polymer-based coatings for the protection of glass surfaces are used considerably in the construction and automotive industries. This research article focuses on the potential use of halloysite nanotubes (HNT)/Poly(Styrene-co-Methylmethacrylate) (PS-co-PMMA) nanocomposites as coatings for the protection of soda-lime glass. The effect of HNT content and coating thickness on the spectral properties of the glass, morphology, surface-wettability, and thermo-mechanical properties of the nanocomposite coatings were investigated and reported. The inherent spectral behavior of glass was not altered significantly by the coatings when the content of HNTs in coatings was ? 5 wt %. The coated glasses also exhibited a slight increase in the solar skin protection factor (SSPF), but notable improvement in the solar material protection factor (SMPF) when the HNT content was high in coatings. Thermogravimetric analysis (TGA) revealed that the HNT/PS-co-PMMA nanocomposite coatings possess excellent thermal stability compared to the neat copolymer. The surface wettability of coated glasses by water droplets decreased substantially due to coatings as evident from contact angle measurements. The HNT/PS-co-PMMA nanocomposites also displayed enhanced tensile strength and scratch resistance with increasing HNT content of coatings up to 5 wt%. Overall, the performance of the coated glass was enhanced by the coatings. © 2018 Elsevier B.V.
PMMA-LZO Composite Dielectric Film with an Improved Energy Storage Density
(2019) Kishor, Kumar, M.J.; Kalathi, J.T.
Energy storage materials in modern electronic devices and renewable energy systems are inevitable. The incorporation of inorganic fillers into the polymer matrix is a promising option for the advancement of storage materials with high energy density. The agglomeration of inorganic fillers in the polymer matrix and phase separation remain the main obstacles to efficient applications of the composites for energy storage. Here, the primary attention was given to achieve a uniform distribution of high-k LZO (Lanthanum Zirconium Oxide) filler into a PMMA (Polymethylmethacrylate) matrix to enhance the dielectric constant and energy storage density of PMMA while keeping dielectric loss at minimum. We prepared PMMA-LZO composite films with variable LZO content by ultrasound-assisted mixing followed by spin coating the solution on ITO (Indium tin oxide) coated glass. The effect of LZO content on dielectric properties of the LZO-PMMA films was studied. Dielectric constant (k) of PMMA was found to be increased from 3.1 to 15.3 at 15 vol.% LZO loading with a dielectric loss of 0.0582. However, 10 vol.% LZO loaded PMMA showed an improved dielectric constant of 13.4 while the dielectric loss remained the same as that of the neat PMMA. The LZO-PMMA films with 10 vol.% and 15 vol.% of LZO loading exhibited maximum energy density of 5.94 J cm?3 and 6.53 J cm?3, respectively. Overall, the 10 vol.% LZO loading was found to be optimum to achieve a stable film with improved dielectric properties. This work provides a viable approach for the development of flexible, high-energy density materials with a minimum dielectric loss. 2019, The Minerals, Metals & Materials Society.
PMMA-LZO Composite Dielectric Film with an Improved Energy Storage Density
(Springer New York LLC barbara.b.bertram@gsk.com, 2019) Kishor Kumar, M.J.; Kalathi, J.T.
Energy storage materials in modern electronic devices and renewable energy systems are inevitable. The incorporation of inorganic fillers into the polymer matrix is a promising option for the advancement of storage materials with high energy density. The agglomeration of inorganic fillers in the polymer matrix and phase separation remain the main obstacles to efficient applications of the composites for energy storage. Here, the primary attention was given to achieve a uniform distribution of high-k LZO (Lanthanum Zirconium Oxide) filler into a PMMA (Polymethylmethacrylate) matrix to enhance the dielectric constant and energy storage density of PMMA while keeping dielectric loss at minimum. We prepared PMMA-LZO composite films with variable LZO content by ultrasound-assisted mixing followed by spin coating the solution on ITO (Indium tin oxide) coated glass. The effect of LZO content on dielectric properties of the LZO-PMMA films was studied. Dielectric constant (k) of PMMA was found to be increased from 3.1 to 15.3 at 15 vol.% LZO loading with a dielectric loss of 0.0582. However, 10 vol.% LZO loaded PMMA showed an improved dielectric constant of 13.4 while the dielectric loss remained the same as that of the neat PMMA. The LZO-PMMA films with 10 vol.% and 15 vol.% of LZO loading exhibited maximum energy density of 5.94 J cm?3 and 6.53 J cm?3, respectively. Overall, the 10 vol.% LZO loading was found to be optimum to achieve a stable film with improved dielectric properties. This work provides a viable approach for the development of flexible, high-energy density materials with a minimum dielectric loss. © 2019, The Minerals, Metals & Materials Society.