Articles written in Bulletin of Materials Science
Volume 10 Issue 5 August 1988 pp 423-433
High molecular weight polyacrylamides were synthesized and successfully modified to contain up to 8·3% hydroxamate functional groups. The selective flocculation tests carried out on 1:1 iron oxide/kaolin mixtures using parent polyacrylamide, polyacrylic acid and the modified polyacrylamide, confirm the possibility of enhancing selectivity through introduction of iron chelating functional groups in commercially available polymers. Starting with a feed grade of 35% iron, 92% recovery with acceptable grade of 60% iron has been achieved using the modified polyacrylamide.
Volume 17 Issue 6 November 1994 pp 911-920
Three different ceramic powders, viz. alumina, zirconia and silicon nitride were dispersed using two polyelectrolytes, one cationic (Betz 1190) and the other anionic (Darvan-C). All powders examined during the study could be well dispersed only under conditions of polymer dosage and pH such that the working pH is at least 2 pH units away from the pHIEP of the powder-dispersant combination. The shift in the isoelectric point (IEP) of the powders were determined through electro-acoustic measurements on 1% volume suspensions. Specific free energy of interaction were also computed using a model based on the electrical double layer theory of surfactant absorption.
Volume 19 Issue 2 April 1996 pp 177-177
Volume 19 Issue 2 April 1996 pp 267-293
Recent advances in the design of fine gravity concentrators and high gradient magnetic separation devices have led to significant improvements in the recovery of tungsten values in fine and ultrafine size range. Amongst the more promising techniques of fine particles processing, encouraging results are reported on froth flotation, shear flocculation and spherical agglomeration of tungsten ore slimes. Development of highly selective reagents such as alkyl hydroxamates, phosphonic acid derivatives and alkylated nitrosonapthols is vital for enhancing separation efficiencies in the slimes size range. Froth flotation of Indian tungsten ore slimes (particularly at Degana) using appropriate reagent combinations appears promising and needs to be examined in greater detail.
Volume 34 Issue 2 April 2011 pp 261-270
Polyaniline (PANI) was synthesized by the oxidation of aniline hydrochloride in the presence of ammonium persulphate and hydrochloric acid. The polymerization reaction was carried out in several batches in different solvent media by changing the volume ratio of 𝑁,𝑁-dimethyl formamide (DMF) and water as binary solvent mixture. The dielectric constant of the polymerizationmedium for each batch reaction was determined by measuring the capacitance with change in frequency. The UV spectra of the synthesized polyaniline solutions helped us to optimize the ratio of the binary solvent to get sufficient polymer growth and processability. Thin film of processable polyaniline was then deposited on glass slides coated with polyvinyl alcohol (PVA) crosslinked with maleic anhydride (MA). FTIR and XRD studies of the coated film were also done. AFM studies further helped in the morphological study of the film deposited. Finally, conductivity and ammonia gas-sensing property of the polyaniline film were also studied.
Volume 42 | Issue 6
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