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Calcium carbonate microparticle growth controlled by a conjugate drug–copolymer and crystallization time
Author(s) -
Doroftei Florica,
Damaceanu Mariana Dana,
Simionescu Bogdan C.,
Mihai Marcela
Publication year - 2014
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520613030357
Subject(s) - vaterite , calcite , crystallization , chemical engineering , calcium carbonate , zeta potential , materials science , dynamic light scattering , microparticle , chemistry , polymer chemistry , nanoparticle , mineralogy , nanotechnology , composite material , engineering , aragonite
The influence of crystallization reaction time on CaCO 3 microparticle growth from supersaturate aqueous solutions, in the presence of a conjugate drug–copolymer, has been investigated. The polymer conjugate, P(NVP‐MA‐Ox), is based on poly( N ‐vinylpyrrolidone–co‐maleic anhydride) as the support and 2‐amino‐5‐(4‐methoxyphenyl)‐1,3,4‐oxadiazole as the drug. The microparticles are characterized by optical, scanning and transmission electron microscopy, dynamic light scattering, X‐ray diffraction, flow particle image analysis and particle charge density. X‐ray diffraction (XRD) investigations showed that calcite polymorph content increased with an increase in crystallization time, even if the electrostatic interactions between Ca 2+ and polyanionic sites of P(NVP‐MA‐Ox) structure conduct to an increased vaterite phase stability. The strong particle size increase after 6 h of ageing can be ascribed to partially vaterite recrystallization and adsorption of nano‐scaled calcite crystallite nuclei at microparticles surfaces. The pH stability of the particles was shown by zeta potential changes and their adsorption capacity as a function of their composition, and characteristics were tested using methylene blue. The sorption capacity of composite materials was strongly influenced by the ratio between polymorphs in the composites, and increased with the increase of calcite content and ageing time.