ABSTRACT
Polyamide complexing capsules containing a poly(acrylic acid) gel are synthesized by a two steps polymerization process with various diameters (10 microm for microcaps or 200 microm for mcaps). A cationic exchange between gel carboxylic functions and metal ions is realized. Extraction and stripping measurements show that the composition of the capsule membrane doesn't hinder the mass transfer. A model, taking account only of the diffusion in the gel phase, is studied.
Subject(s)
Drug Compounding/methods , Metals/chemistry , Acrylic Resins/chemistry , Algorithms , Excipients , Hydrogen-Ion Concentration , Ion Exchange , Kinetics , Microscopy, Electron, Scanning , Models, Chemical , Nylons/chemistry , Particle SizeABSTRACT
Polyterephthalamide microcapsules containing a poly(acrylic acid) gel as a macromolecular ligand (PAA-CAPS) were prepared using an original two step polymerization process in a water-in-oil inverse emulsion system. A polyamide microcapsule containing acrylic acid, initiator and cross-linking agent, is formed by interfacial polycondensation of terephthaloyl dichloride with hexamethylenediamine. In situ radical polymerization of the microcapsule core acrylic acid is initiated to obtain encapsulated poly(acrylic acid) gel. Reference polyamide microcapsules, i.e. without ligand (CAPS), were also synthesized. The mean diameter of synthesized microcapsules was 210 microm, and the microcapsule wall thickness was evaluated by SEM and TEM observations of microcapsule cross-section cuts. The microcapsule water content was determined by thermogravimetric experiments. The extractabilities of Cu(II), Ni(II), Co(II) and Zn(II) into PAA-CAPS were examined. The stripping of the various cations can be promoted in diluted hydrochloric acid solutions.
