N. Raghavendra

Mechanical behavior of organo-modified Indian bentonite nanoclay fiber-reinforced plastic nanocomposites

The aim of the research was to examine the influence of organo-modified Indian bentonite (IB) nanoclay dispersed in vinylester on the mechanical properties of nanoclay/vinylester/glass nanocomposites. Nanoclay was organically modified using cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) by cation exchange method and dispersed in vinylester using ultrasonication and twin screw extrusion. XRD of nanoclay/vinylester revealed exfoliation at 4 wt.% nanoclay indicating uniform dispersion in the polymer. DSC results showed improvement in glass transition temperature by 22.3% in 4 wt.% nanoclay/vinylester/glass when compared with that of vinylester/glass. Nanoclay/vinylester/glass with 4 wt.% nanoclay showed 29.23%, 23.84% and 60.87% improvement in ultimate tensile strength (UTS), flexural strength (FS) and interlaminar shear strength (ILSS) respectively when compared with those of vinylester/glass. The mode of tensile failure examined by SEM showed no agglomeration of nanoclay in 4 wt.% nanoclay/vinylester/glass specimens.

Combined influence of organo-modified Indian bentonite nanoclay and fire retardants on thermal and fire behavior of vinylester

This article reports synergetic effect of naturally available Indian bentonite nanoclay and fire retardants on the thermal and fire retardation behavior of vinylester. Indian bentonite nanoclay organically modified with hexadecyltrimethylammonium bromide by cation exchange capacity method, along with aluminum trihydroxide and magnesium hydroxide were dispersed in vinylester and tested. Addition of 30% aluminum trihydroxide and 4 wt% Indian bentonite increased the glass transition temperature of vinylester by 24.4%; decreased thermal degradation by 47%, vertical burning rate by 54% and horizontal burning rate by 72%; and increased limiting oxygen index by 56.6% and microhardness by 49.6%.

DEVELOPMENT AND CHARACTERIZATION OF TITANIUM PHOSPHATES (TIP2O7) AND LITHIUM TITANIUM PHOSPHATE (LITIP2O7) AND THEIR THERMAL AND ELECTRIC PROPERTIES.

In this present study, the Titanium phosphates (TiP2O7) and Lithium titanium phosphate (LiTiP2O7) materials were synthesized by using soft hydrothermal method at moderate pressure and temperature conditions. The resultant materials were characterized by using P-XRD, SEM, EDAX, FTIR, TGA, DSC and Electrochemical impedance spectra (EIS). From P-XRD, confirms the well crystalline rhombohedral phase and was found to be in the range below 100 nm. FTIR spectra indicated that there is an increase in the degree of splitting and stretching of the vibration bands, whereas the splitting of vibration bands and polymerization of [PO4] decreased as the Ti ions. The TGA/DSC studies revealed that, these materials display endothermic reactions due to the liberation of ligands and diffusion. Thermal stability of the materials improved and the dielectric constant decreases. AC conductivity measurements for both the samples were carried and results are plotted. From AC conductivity studies, it is observed that the ionic conductivity of dc conductance of sample was measured show the frequency dependence dc capacitance of LiTiP2O7 material. The frequency response dc capacitance also depends on doping with titanium.

Comparative Study of Different Immobilization of Strontium inLiSr2(PO4)3 Crystal through Hydrothermal Process

The main objective of the present study was to synthesis the different immobilization of Sr+2 in LiSr2(PO4)3crystals using soft hydrothermal method at moderate pressure and temperature conditions.The powder X-ray diffraction confirms that, the synthesized LiSr2(PO4)3material has very good phase purity and crystalline with rhombohedralstructure.The energy-disperse X-ray (EDX) spectroscopic analysis shows their elemental composition correlating well with that of the strontium.Observation through a Scanning Electron Microscope (SEM) shows that microstructures of good quality and exhibited smooth surface, sub transparent and sub vitreous lustre. The FTIR studies was used to determine whether the bond structures were affected from the doping or not and revealed that the presence of O-H molecules and minute structural variations of synthesized materials.The TGA graph, temperature vs. weight % loss decreases with increasing the temperature showsLithium strontium phosphateas thermally stable so it is used as some optoelectronic device applications.The electrical conductivity of LiSr2(PO4)3was investigated as a function of the nature of the transition-metal cation. Impedancemeasurementshow that the materials have relatively good ionic conductance.

Preparation of chitosan/different organomodified clay polymer nanocomposites: studies on morphological, swelling, thermal stability and anti-bacterial properties

B. H. Nanjunda Reddy, V. Venkata Lakshmi∗,2, K. R. Vishnu Mahesh∗∗,3, M. Mylarappa, N. Raghavendra and T. Venkatesh Department of Chemistry, Amrita School of Engineering, Bengaluru, Campus, Amrita Vishwa Vidyapeetham University, Bangalore–560035, Karnataka, India Department of Studies and Research in Chemistry, B.H̃ Road, Tumkur University, Tumkur–572103, Karnataka, India Research center, Department of Chemistry, AMC Engineering College, Bengaluru–560083, India Department of Chemistry, Dayananda Sagar College of Engineering, Sahvige Malleshwara Hills, Kumara Swamy Layout, Bangalore–560083, Karnataka, India CMRTU, RV College of Engineering, Bengaluru–560059, Karnataka, India Department of Chemistry, ACS College of Engineering, Bengaluru–560074, Karnataka, India ∗laxmimurthy@rediffmail.com, ∗∗vishnumaheshkr@gmail.com

A facile hydrothermal recovery of nano sealed MnO2 particle from waste batteries: An advanced material for electrochemical and environmental applications

This work deliberates a method for manganese (Mn) recovery as manganese oxide obtained by leaching of waste batteries with 3M sulphuric acid. The Experimental test for the recovery of Mn present within the waste dry cell batteries were carried out by a reductive leachant. Elemental composition of leached sample was confirmed by Energy Dispersive X-ray analysis (EDAX), and Surface morphology of the recovered MnO2 was examined by using Scanning Electron microscopy (SEM). Phase composition was confirmed from X-ray Diffractro meter (XRD). The obtained leached solution was treated with 4M NaOH, yielded to Manganese Dioxide with high extraction degree, while it do not touches the Zn content within the solutions. The recovered samples were characterized using XRD, EDAX, SEM and Fourier transform infrared spectrometry (FTIR). The electrochemical properties of the as-recovered sample from leached solution was examined used cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Remarkably, the 80 wt.% MnO2 displays reversibility, diffusion constant, smaller equivalent series resistance and charge transfer resistance in 0.5M NaOH showed superior results as compared to alternative electrolytes. The ideal capacitive behaviour of MnO2 electrode and nano particle was applied to photocatalytic degradation of dyes.

Organomodified Clay and its Influence on Thermal and Fire Behaviors of Clay/Fire Retardant/Poly Vinyl Ester Composites

The objective of this research was to examine the synergistic effect of organomodified nanoclay and fire retardants on the thermal decomposition, glass transition temperature and fire retardation behaviour of nanoclay/Poly vinyl ester composites. The two nanoclays such as Cloisite-15A and Cloisite-Na are used along with two fire retardants as Aluminium Tri Hydroxide (ATH) and Magnesium Hydroxide (MH) in the present study. The nanoclay/fire retardants were dispersed in poly vinyl ester using twin screw extrusion. TEM and AFM of nanoclay/Poly vinyl ester specimens revealed that 4 wt% Cloisite-15A/Poly vinyl ester exhibited exfoliation and distribution of nanoclay which were superior to that of Cloisite-Na/Poly vinyl ester. The synergistic effect of Cloisite-15A and 30 % ATH increased glass transition temperature by 18 % and reduced thermal degradation by 47 % and Limiting Oxygen Index (LOI) by 52 % when compared with that of Poly vinyl ester after the curing process in all the cases.