NOPR Community:

Effect of condensation product on bright zinc electrodeposition from sulphate bath

Sat, 01 Sep 2001 00:00:00 GMT

Title: Effect of condensation product on bright zinc electrodeposition from sulphate bath Authors: Naik, Y Arthoba; Venkatesha, T V; Nayak, P Vasudeva Abstract: Zinc electroplating is carried out in presence of condensation product formed between -Alanine and Glutaraldehyde. The bath constituents are optimized through Hull cell experiments. Operating parameters such as pH, temperature, current density are also optimized. Current efficiency and throwing power are measured. Polarization study reveals high shift of potential towards negative direction in the presence of addition agents. Corrosion resistance test indicated good protection of steel by the coating. IR spectrum of the deposit shows the inclusion of the compound. SEM photomicrographs show fine grained deposit in the presence of addition agent. The consumption of brightener in the lab scale is 8 mL for 1000 amp-hour. Page(s): 390-395

Synthesis, characterisation and evaluation of heated rubber seed oil and rubber seed oil-modified alkyd resins as binders in surface coatings

Sat, 01 Sep 2001 00:00:00 GMT

Title: Synthesis, characterisation and evaluation of heated rubber seed oil and rubber seed oil-modified alkyd resins as binders in surface coatings Authors: Aigbodion, A I; Pillai, C K S; Bakare, I O; Yahaya, L E Abstract: Rubber seed oil (RSO) heated at 300 ± 5°C for six hours and RSO-modified alkyd resins were evaluated as binders for surface coatings. During heating of rubber seed oil, the bulk viscosity varied exponentially with time. GPC analysis showed that RSO consists of a very high molecular weight fraction that is uncommon in vegetable oil in addition to free fatty acid, mono-di-, tri-glycerides and oligomeric tryglycerides. Values of _n and _w of 7393 and 13076 respectively were found for RSO. Heated rubber seed oil (HRSO) gave _n of 475 and _w of 599: while RSO-modified alkyd samples of oil contents of 40% (I), 50% (II) and 60% (III) gave _n of 3234, 1379 and 3304 respectively; and _w of 6186, 2147 and 8406 respectively. HRSO is narrowest in size distribution compared to RSO and all the alkyd samples as indicated by their polydispersity indices. RSO was found to be semi-drying as the film remained tacky after long period (about 48h) of exposure. Heating enhanced its drying ability. The HRSO films exhibited reasonable pencil hardness and excellent resistance to acid and salt solution but poor resistance to alkali solution compared to the alkyd samples. The drying ability and chemical resistance of HRSO and RSO-modified alkyd were greatly enhanced by modification with cashewnut shell liquid-formaldehyde resin (10% wl w). Page(s): 378-384

The History of Iodine From Discovery to Commodity

Thu, 01 Nov 2001 00:00:00 GMT

Title: The History of Iodine From Discovery to Commodity Authors: Wisniak, Jaime Abstract: The discovery of iodine by accident and the turning of this event into its industrial manufacturing constitutes a fascinating chapter in the development of chemical technology. We see in it how political and economical events brought drastic changes in the raw materials used and the production technologies. From a strictly European activity it turned into an important economic commodity for Chile and Japan. Page(s): 518-526

Synthesis and characterization of new polycrown ether (schiff base)

Thu, 01 Nov 2001 00:00:00 GMT

Title: Synthesis and characterization of new polycrown ether (schiff base) Authors: Dutta, Pradip Kumar Abstract: A semirigid 32-membered ring dialdehyde crown ether, bis (5-aldoxy-1, 3-phenylene)-32-crown-10 (3), has beensynthesized in one step using 3,5-dihydroxy benzaldehyde (1) and tetra (ethylene glycol) dichloride (2) in the presence of sodium hydride in DMF. A direct polycondensation reaction of bis (5-aldoxy-1 ,3-phenylene)-32-crown-10(3) and diamines (5) in DMF formed a high molecular weight poly crown ether (schiff base). The polymers are characterized by viscometry, elemental analysis, IR and NMR spectroscopies. The polymers are soluble in common organic solvents. The thermal characteristics of the polymers have been studied by TGA and DTA. Page(s): 515-517