MOSIEWICKI mirna Alejandra
congresos y reuniones científicas
Preparation and characterization of nanocomposite films based on chitosan and magnetite
Composites obtained with chitosan as a biocompatible polymeric matrix and a dispersed phase of iron oxide nanoparticles can be used in the development of valuable materials with potential applications in fields like biomedicine or biotechnology. Particularly, the interest in nanomagnetite based films is related with the fact that even embedded in a polymer matrix, these nanoparticles can be oriented using an external magnetic field. Some of the potential applications of these systems are as targeting drug carriers, hyperthermia local inductors for cancer therapy, pollutant removals, biosensors and magnetic cell separators1-2. In this work, the physical, mechanic and magnetic characteristics of nanomagnetite-chitosan composite films obtained by a simple processing method are presented3.The films were prepared by casting of solutions containing chitosan, iron salts and occasionally glycerol (to evaluate the effect of a plasticizer). Once the films were dried, magnetite nanoparticles were precipitated by immersing the films in a concentrated sodium hydroxide solution. The films were finally washed with distilled water until neutral pH. To estimate the nanoparticle size in the composites, DRX measurements were carried out and the results obtained were in agreement with those found by TEM observations. The last technique allowed also to determine that the nanoparticles precipitated in non-plasticized films have a narrow size distribution and are well dispersed into the chitosan matrix. The overall analysis of data obtained from thermogravimetric analysis, infrared spectroscopy and moisture sorption tests indicated that different but strong interactions between nanomagnetite particles and chitosan matrix took place. Consequently the nanocomposites are less thermally stable, but also less hydrophilic than the corresponding matrices. Additionally, the presence of magnetite causes important changes in the superficial microstructure of the films that led to different contact angles and to a more fragile but stiff behavior as particle concentration increases. The curves of magnetization versus temperature demonstrated that super-paramagnetic behavior was obtained for composite films containing 5, 7, and 10 wt % magnetic nanoparticles (MNP), while in the less concentrated samples the diamagnetic contribution of the matrix is the dominant magnetic effect. Moreover, plasticized samples showed lower magnetization and higher coercitivity than unplasticized ones for the same nanomagnetite content.1.Mürbe, J., Rechtenbach, A., Töpfer, J., Synthesis and physical characterization of magnetite nanoparticles for biomedical applications // Mater. Chem. Phys. ? 2008 ? Vol. 110 ? P. 426-433. 2.Yuwei, C., Jianlong, W. Preparation and characterization of magnetic chitosan nanoparticles and its application for Cu(II) removal // Chemical Engineering Journal ? 2011 ? Vol 168 ? P. 286?292.3.Kloster, G. A., Marcovich, N. E., Mosiewicki, M. A. Composite films based on chitosan and nanomagnetite. European Polymer Journal,, 2015.