EFFECTS OF PHOS-b-PMAA ADDITIVE AND pH ON THE FORMATION OF CALCIUM CARBONATE COMPOSITE MICROPARTICLES

The influence of environmental pH on the crystallization of calcium carbonate microparticles from supersaturated aqueous solutions in the presence of poly(p-hydroxystyrene-b-methacrylic acid) PHOS-b-PMAA, was investigated. The formation of CaCO3/PHOS-b-PMAA microparticles under different polymer concentrations at pH = 12, when both copolymer blocks are ionized, was compared to microparticles preparation at pH = 9.5, when only the PMAA block is ionized. The morphology of the composites was investigated by scanning electron microscopy and atomic force microscopy, and the polymorphs characteristics by X-ray. diffraction and Raman spectroscopy. The particles mean size and circularity was followed by flow particle image analysis and the polymer presence into the composite particles was evidenced by thermogravimetric analysis, particles charge density and zeta potential.