Faculty Publications
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Item 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. © 2017 Elsevier Ltd.Item 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.Item 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.Item 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.Item 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.