Role of Polyelectrolytes in Crystallogenesis of Calcium Carbonate |
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Authors: | Amane Jada Khalil Jradi |
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Affiliation: | Institut de Chimie de Surface et Interface, 15 rue Jean Starcky, 68057 MULHOUSE, France |
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Abstract: | The effects anionic polyelectrolytes, having various molecular weights and repeating unit structures, on the crystallization of calcium carbonate in supersaturated solutions are studied. The induction times of the crystals grown in the presence of the polymers were optically evaluated; X-ray diffraction and Scanning Electronic Microscopy (SEM) analyses were performed to determine, respectively, their crystalline structures and morphologies. The polyelectrolyte is found to lengthen the induction time and to reduce the size of CaCO3 nanocrystallites, to an extent depending on the interaction efficiency between the polymer anionic repeating units and the calcium ions. Further, depending on their sizes and their crystalline structures (calcite, vaterite) the nanocrystallites aggregate and yield final calcium carbonate particles having various sizes and morphologies. The data indicate that nanocrystals having vaterite structure, as determined by X-ray analysis, give spherical CaCO3 final particles, while nanocrystals having calcite structure lead to either acicular or flower shapes of CaCO3 final particles. |
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Keywords: | crystallization electron microscopy filler mineral polyelectrolytes |
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