Showing papers by "Anjanapura V. Raghu published in 2014"
TL;DR: In this paper, the intrinsic epoxy groups on the graphene were utilized for reaction with stearic acid to minimize the negative impact of the normal functionalization method on the π-electronic system of graphene.
Abstract: Graphene, prepared by the thermal reduction of graphite oxide (GO), was modified with stearic acid to enhance its lipophilicity. A novel method, using the intrinsic epoxy groups on the graphene, was utilized for reaction with stearic acid to minimize the negative impact of the normal functionalization method on the π-electronic system of graphene. Gravimetric analysis, thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) showed that the stearic acid was effectively attached to the graphene. In addition, Raman spectroscopy and electric conductivity of the graphene showed that this novel modification method, utilizing intrinsic defects, did not damage the π-electronic system of the sp2 bonded carbons. The dispersion of graphene in a low density polyethylene (LDPE) matrix was enhanced; consequently, the reinforcing effect in tensile testing was improved by the lipophilic modification. The crystallization behavior observed by differential...
186 citations
TL;DR: In this paper, mixed matrix membranes of polyvinyl alcohol loaded with zeolite particles having different silica alumina ratio were prepared and used in the pervaporation dehydration of ethanol and isopropanol (IPA) from their aqueous mixtures.
Abstract: Mixed matrix membranes of poly(vinyl alcohol) loaded with zeolite particles having different silica alumina ratio were prepared and used in the pervaporation dehydration of ethanol and isopropanol (IPA) from their aqueous mixtures. The membranes were characterized by physicochemical techniques that revealed higher interaction between polymer and zeolite particles having higher alumina than those with lower alumina in the zeolite framework. Both, membrane selectivity to water and flux were increased as the alumina content in the zeolite increases. Separation factors of zeolite with lower alumina incorporated membranes were, respectively, 236 and 334 for the feed mixture compositions of 4 wt% water in ethanol and 10 wt% water in IPA at 30°C. On the other hand, membranes containing zeolites with higher alumina content showed slightly higher separation factors of 349 and 568, respectively, for the same feed mixtures at 30°C. Such an incremental improvement in membrane performance with increase in alumina content in the zeolite framework is attributed to favorable interaction between zeolite particles and the polymer matrix. POLYM. ENG. SCI., 54:1774–1782, 2014. © 2013 Society of Plastics Engineers
106 citations
TL;DR: In this article, the para-toluene sulfonic acid (p-TSA) treated clay (5, 10 and 15 W.% loadings) particles were inserted into NaAlg matrix to derive the composite membranes that showed enhanced pervaporation performance for isopropanol separation.
85 citations
TL;DR: In this article, four novel segmented polyurethanes (PUs) based on 4,4′-{oxy-1,4-diphenyl bis(nitromethylidine) diol with different diisocyanates have been prepared by solution method and the structures of ODBNMD and PUs have been confirmed by Fourier transform infrared (FTIR), nuclear magnetic resonance (1H-NMR), UV-visible, and fluorescence spectroscopies.
Abstract: Four novel segmented polyurethanes (PUs) based on4,4′-{oxy-1,4-diphenyl bis(nitromethylidine)}diphenol (ODBNMD) diol with different diisocyanates such as 4,4′-diphenylmethane diisocyanate, toluene 2,4-diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate have been prepared by solution method. The structures of ODBNMD and PUs have been confirmed by Fourier transform infrared (FTIR), nuclear magnetic resonance (1H-NMR and 13C-NMR), UV-visible, and fluorescence spectroscopies. The segmented PUs were further characterized by thermogravimetry (TGA), differential scanning calorimetry (DSC), and wide-angle X-ray diffraction. FTIR confirmed hydrogen bonding interactions, whereas TGA and DSC suggested that introduction of aromatic/phenyl ring in the main chain considerably increased the thermal stability. POLYM. ENG. SCI., 54:24–32, 2014. © 2013 Society of Plastics Engineers
62 citations