Some physico-chemical properties of prepared metallic soap-driers of aluminium, copper and zinc.

Abstract

Considerable work has been done on the drying effects of various soaps in surface coatings. Payne (1954) reported the drying behaviour of twenty metals and their various soaps and observed a wide range of activity of the metals with Cobalt, Vanadium and Manganese. Kirk-Othmer (1985) observed that the combination of two or more metals is preferred because each one has a specific action in the drying process e.g. lead is usually considered to be "thorough drier" and cobalt a "surface drier", manganese is more surface than thorough. Zinc retards surface drying but promotes drying by keeping the surface open for continued oxygen penetration and absorption.Driers are a group of water insoluble metallic soaps which contain either alkaline earth metals, for example Aluminium, calcium or heavy metals such as Zinc, copper e.t.c., combined with monobasic carboxylic acids of seven to twenty-two carbon atoms (Ulmanns, 2001). These drier soaps are soluble in organic solvents and are the most important group of metallic soaps used as additives in coatings (paints, vanishes, ink, lacquers) to speed up the physical change from the liquid to the solid state thereby reducing the drying time (Omeike, 1996). Primary (active) driers initiate drying process on their own, with Cobalt being the most active drier since it effects rapid surface drying and is generally used in conjunction with auxiliary driers to improve or modify the final properties of the coatings (Kirk-Othmer, 1985). Driers can be prepared by fusion or precipitation method. The precipitation process consists of two chemical steps:The present study investigates the optimum pH ranges for precipitation of Al, Cu and Zn soaps and their metal contents suitability as driers for surface coatings.Sample Collection: Palm kernel oil was obtained at Katako market in Jos Plateau State. The oil was vacuum filtered at 25 0 C. Parameters such as Acid, Iodine and Saponification numbers were determined by conventional methods. All reagents and solvents were analyte grades (AR) Preparation of Soluble Soaps:From the saponification value of the oil, calculated amount of 50 % w/v NaOH was obtained. To 500 g of the oil was added the calculated amount of 50 % w/v NaOH solution in a stepwise manner. Excess of few drops were added to ensure complete saponification. Furthermore, the soap solution formed was warmed over a steam bath while stirring for about 30 mins and thereafter overnight to solidify. The dried soap was ground into powdery form.Determination of pH of Soap: 10 g of the powdered soap was weighed and dissolved in distilled water in a 100 ml volumetric flask. This was made up to prepare 10 % soap solution. The pH of the 19 % soap solution was determined using a pH meter.Preparation of Metallic Soaps: 0.5 M solution metals salts of Aluminium (AlCl3), Copper (CuSO4. 7H2O ) and Zinc (ZnSO4) were prepared and kept in amber bottles. To 20cm 3 of 10 % soap solution was added 10 cm 3 of 0.5 M HCl and in each case, titrated against each of the metal salt solution until complete precipitat...

Metal Ion Improved Properties of Burning Candle

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A combined physical–chemical and microbiological approach to unveil the fabrication, provenance, and state of conservation of the Kinkarakawa-gami art

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