The Precipitation of Alkaline-Earth Metal Polyacrylate Hydrate Powders from Aqueous Solution: Ionic Equilibria, Precipitate Compositions and Morphologies

✍ Scribed by Dr. A. Packter; S. Sabir

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 263 KB
• Volume: 21
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.2170210205

✦ Synopsis

The precipitation of barium, strontium, calcium and magnexium polyacryate hydrates was studied from equivalent aqueous solutions of initial concentrations 0.03 M to 0.30 M a t ambient temperature: sodium polyacrylate (m.wt = 30,000 t o 300,000) was added t o metal chloride solution. The final yields of precipitate increased with decreasing solubility and/or peptisation (Ba > Sr > Ca > Mg) and increasing molecular weight of the polyacrylate; the precipitates had the compositions [BaA(COO), 1 1 -2 H2OIn, [SrA(COO), -. 1 -2 H2OIn, [CaA(COO), -2 H,OIn and [MgA(COO), . 2 H,O],. The final yields of the precipitates from sodium polyacrylate solutions were far lower and these had the compositions [NaZ,M1 -,CA(COO), . 2 H,O], ; A = -CH -CH, -CH -.

The metal polyacrylate hydrate powders consisted of microcrystalline 'spherules' ; their average diameters were from 0.03-0.05 pm (for lower m.wt products) t o 0.01 t o 0.02 p,m (for higher m.wt products).