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Franklin D.S.,Manonmaniam Sundaranar University | Guhanathan S.,Muthurangam Government Arts College Autonomous
Iranian Polymer Journal (English Edition) | Year: 2014

Hydrogels are three-dimensional polymeric networks with segments of hydrophilic groups. Stimuli-responsive hydrogels have played attractive role toward much research due to slight modification of environment by abrupt changes in swelling behavior. In this study, a series of pH-sensitive biocomposite hydrogels were acquired through solvent-free green approach by utilization of diethylene glycol (DEG), citric acid (CA), acrylic acid (AA) and hydroxyapatite (HA). Incorporation of hydroxyapatite (HA) prepared from waste eggshells with ACD resulted in the biocomposite hydrogel (ACD–HA). The synthesized biocomposite hydrogel was examined by various characterization techniques, viz., spectral (FTIR), powder X-ray diffraction (XRD) technique, thermal (TGA and DTG), morphological (SEM) and swelling equilibrium studies. In addition, HA was surface treated with two different silane-based coupling agents, namely 3-aminopropyltrimethoxysilane (AMS) and vinyltriethoxysilane (VES) on the performance properties of biocomposite hydrogels. The results of the studies revealed that VES-treated ACD–HA had superior properties than AMS-treated ACD–HA and untreated ACD–HA on overall properties of biocomposite hydrogels. Hence, the decreasing order of swelling equilibrium behavior in various pH, viz., 4.0, 6.0, 7.4, 8.0, 10.0, has been listed as ACD–HA–VES > ACD–HA–AMS > ACD–HA > ACD. The observations indicated that hydrogels’ adaptability with pH-tuned properties may have greater potential in eco-friendly approaches such as metal ion removal, dye removal and agrochemical release. © 2014, Iran Polymer and Petrochemical Institute.

Elango G.,Government Arts College | Guhanathan S.,Muthurangam Government Arts College Autonomous
Asian Journal of Chemistry | Year: 2011

Three copolyesters were synthesized using 2,3-butane diol with phthaloyl chloride. 2,5-Ditertiary butyl quinol, 1,2-propane diol and 1,5-naphthalene diol were used as another diols for the synthesis of random copolymer. Thermal studies were carried out using DSC and TGA. Results of the investigation confirm relatively new entry copolymers in the family of thermally stable copolymers.

Geetha K.,Muthurangam Government Arts College Autonomous
Journal of Applied Pharmaceutical Science | Year: 2013

The present investigation reports, the novel synthesis of Copper and Copper oxide nanoparticles using Chemical reduction method and its physicochemical characterization. The nanoparticles have been prepared using Copper (II) succinate as precursor. Copper nanoparticles are initially formed and subsequently oxidized to copper oxide. As reported the nanoparticles were characterized by UV-visible spectroscopy, Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction measurements (XRD) and scanning electron microscopy (SEM). SEM analysis exhibited nanoparticles with an average diameter of about 45nm. XRD analysis revealed broad pattern of fcc crystal structure of copper metal and cubic cuprites structure for Cu2O. The antimicrobial properties of copper nanoparticles were investigated using Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. The bactericidal effects of copper nanoparticles were studied based on diameter of inhibition zone in disk diffusion tests of nanoparticles dispersed in batch cultures. The copper nanoparticles showed excellent activity against Escherichia coli and Staphylococcus aureus, with excellent inhibition zones of 14 mm and 10 mm, respectively. Bacterial sensitivity to nanoparticles was found to vary depending on the microbial species. © 2013 Arunachalam Dinesh Karthik and Kannappan Geetha.

Franklin D.S.,Manonmaniam Sundaranar University | Guhanathan S.,Muthurangam Government Arts College Autonomous
Journal of Applied Polymer Science | Year: 2015

Utilization of hydrogels in a simple, low-cost, solventless. and greener approach toward the pH-responsive hydrogels which comprise of citric acid (CA) with varying glycol unit viz., ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) were prepared along with methacrylic acid (MAA). The formations of pre-polymer and hydrogels were confirmed using 13C-NMR and FT-IR spectral techniques. Thermal studies (TGA, DTA, and DSC) and morphology (SEM) of various hydrogels have been investigated. Swelling studies of hydrogels at different pH ranging from 4.0 to 10.0 have also been performed. The results of swelling studies imply that the percentage of swelling is comparatively higher at neutral pH than acidic and alkaline pH. The reciprocal relationship was identified among thermal stability and swelling behavior of hydrogels while increasing the chain length from EG to TEG. © 2015 Wiley Periodicals, Inc.

Karpagam S.,Vellore Institute of Technology | Guhanathan S.,Muthurangam Government Arts College Autonomous | Sakthivel P.,Vellore Institute of Technology
Polymer Bulletin | Year: 2012

Partially conjugated monobenzo 18-crown-6 substituted oligo (p-phenylenevinylene) (MB-OPV) was synthesized via Wittig route. Formation of the oligomer was characterized by spectral (FTIR, 1H NMR, and 13C NMR), elemental and gel permeation chromatography analysis. The morphology of the oligomer film of one-dimensional (1D) and three-dimensional (3D) architectures were observed using atomic force microscopy. The oligomer showed excellent photoluminescence (PL) of bluish green emission at shorter wavelength of 542 nm. Stability of the polymer and glass transition temperature was determined by TGA/DSC. The dielectric properties such as dielectric constant and loss factor for the oligomer have also been studied with respect to change of frequency (50 Hz-5 MHz) and temperature (30-90 °C). The value of dielectric constant decreased with increasing frequency which indicates that the major contribution comes from orientation polarization. The value of dielectric constant increased with increasing temperature which is due to greater freedom of movement of the dipole molecular chains within the oligomer at high temperature. © Springer-Verlag 2011.

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